Emerging Energy Technology - Sustainable

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Emerging Energy Technology
- Sustainable Approach
ISBN: 978-93-83083-73-2
First Impression: 2014
© Krishi Sanskriti
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ISBN: 978-93-83083-73-2
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Emerging Energy Technology
- Sustainable Approach
Editor:
Prof. (Dr.) Govind Chandra Mishra
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Preface
19th April, 2014
From the Desk of Editor………………
On behalf of organizing committee, I extend my heartiest and warmth welcome to
the distinguished delegates and participants of the International Conference on
“Innovative Trends in Applied Physical, Chemical, Mathematical Sciences and
Emerging Energy Technology for Sustainable Development”(APCMET-2014)
being held at Jawaharlal Nehru University, New Delhi, on 19th and 20th April, 2014,
organized by Krishi Sanskriti. Surely, this Conference will help a lot to increase your
knowledge bank. The conference is a source of powerful influence as it draws upon
the expertise from various disciplines and also able to bring together leading
authorities from academia, industry, R&D Institutions and sustainable management
societies for focusing on innovative trends in Applied Physical, Chemical,
Mathematical Sciences and Emerging Energy Technology in order to achieve
universal goal of sustainable development. The importance of this conference lies in
the fact that during this duration, the feasibility of certain policies for innovations
within the applied sciences and emerging energy technology as well as other applied
engineering subjects with a special emphasis in physical, chemical and mathematical
sciences in terms of harnessing eco-friendly technologies and its proper utilization in
order to achieve sustainable development will be explored.
This conference will act as a major forum for the presentation of innovative ideas,
approaches, developments and research projects in the area of theoretical as well as
applied aspects for sustainable development. The (APCMET-2014) committee
invited original Submissions from researchers, faculties, scientists and students that
illustrate analytical research results, review works, projects, survey works and
industrial experiences describing significant advances in the areas related to the
relevant themes and tracks of the conferences. This effort guaranteed submissions
from an unparalleled number of recognized top-level researchers. All the
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
(i)
Preface
submissions underwent a strenuous peer-review process which comprised expert
reviewers. Besides the members of the Technical Program Committee, external
reviewers were invited on the basis of their specialization and expertise. The papers
were reviewed based on their technical content, originality and clarity. The entire
process which includes the submission, review and acceptance processes was done
electronically. There were a total 194 submissions to the conference and the
Technical Program Committee selected 125 papers for presentation at the conference
and Subsequent publication in the form of edited book titled “Emerging Energy
Technology perspectives-A Sustainable Approach” published by Excellent Publishing
Hours, New Delhi. This small introduction would be incomplete without expressing
our gratitude and thanks to the General and Program Chairs, members of the
Technical Program Committees, and external reviewers for their excellent and
diligent work. Thanks to the Jawaharlal Nehru University, New Delhi, for providing
venue for this conference. Finally, we thank all the authors who contributed to the
success of the conference. We also sincerely wish that all attendees will get benefited
academically from the conference and wish them every success in their research
Endeavour.
Dr. G. C. Mishra
Editor
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
(ii)
Contents
Preface
1.
Protection of Load through Ferrite Beads Using Marx Generator
i
1
Aman Jain, Manish Pratap Singh, Apoorv Shankar, Vikram Kumar
2.
Mechanically Autonomous System for Efficient Coach Water Refilling in Indian Railways
6
Aman Kaushik
3.
Performance Analysis of Hybrid Solar Photovoltaic-Thermal Collector
12
Amit Verma, Sunita Chauhan
4.
Design and Implementation of SPWM and Hysteresis based VSI Fed Induction Motor
17
Amruta Pattnaik, Haymang Ahuja, Shubham Mittal, Nisha Kothari, Tushar Sharma
5.
A Comparative Study on TiO2and SiOx Dielectric based MOS Capacitance
25
Ashik Some, Diksha Barnwal, Arnab Shome, Birojit Chakma,
Lalaram Arya, B.S. Thoma, Aniruddha Mondal
6.
Cost- Benefit Analysis of Two-Dissimilar Units Warm Standby System Subject to
Electromagnetic Vibrations with Switch Failure
31
Ashok Kumar Saini
7.
Study on Power System Planning in India
41
Dharmesh Rai, Vinod Kumar Yadav, Syed Rafiullah, Adesh Kumar Mishra
8.
Effect of Reforms in Distribution Sector in Indian Power Scenario
48
J Sai Keshava Srinivas
9.
Biogas- An Alternative Source of Energy
53
Mohd Junaid Khalil, Kartik Sharma, Rimzhim Gupta
10.
Fuel Cell: the Future of the Electric Power System
60
Mamta Chamoli, Yuvika Chamoli
11.
The State of Art of MEMS in Automation Industries
67
Anupriya Saxena, Man Mohan Singh and Indra Vijay Singh
12.
Dynamic Economic Power Dispatch Problem Using Differential Evolution
72
Nandan Kumar Navin, Sonam Maheshwari
13.
Emission Constrained Economic Load Dispatch Problem Using
Differential Evolution Algorithm
82
Nandan Kumar Navin
14.
Pumped Storage Concept and its Potential Application in Nepalese
Hydropower Context – A Case Study of Chilime Hydropower Plant Rasuwa, Nepal
91
Niroj Maharjan, Sailesh Chitrakar, Nikhel Gurung, and Ravi Koirala
15.
Super Capacitor Power System for Sounding Rocket Payloads
100
P.P.Antony, S. Saju, R.G.Hari kumar Warrier, B.Manoj Kumar
16.
Recent Advances in Hydrogen Production
108
C. Bharadwaj Kumar, P. Sreedhar, J. Santoosh, S. S.Chaitanya.B, Y.Satya Prasad, M. Devika
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Contents
17.
Design of ADRC Load Frequency Controller for Three Area Power System
116
Pallavi Gothaniya
18.
LQR Based LFC for Two Area Interconnected Power System with AC/DC Link
124
Pallavi Gothaniya
19.
Real Time Power Generation Using Piezoelectric Ceramic Disc
for Low Voltage Appliances
133
Arpit Bansal, Akshita Jain, Rachit Agrawal, Pradeep Kumar, Ashutosh Gupta
20.
Smart and Functional Materials in Technological
Advancement of Solar Photovoltaic’s
138
R.C.Sharma and Ambika
21.
Sputtering Pressure Dependent Structural, Optical and Hydrophobic
Properties of DC sputtered Pd/WO3 thin films for Hydrogen Sensing Application
146
An Assessment of Perform Achieve and Trade Mechanism - A Case
Study of Industries in District Ropar, Punjab
155
Sonam Jain, , Amit Sanger, Ramesh Chandra
22.
Ravneet Kaur
23.
Migration of Landfill Gas From the Soil Adjacent to the Landfill
165
M. J. Khalil, Rimzhim Gupta, Kartik Sharma
24.
Self – Energy Generating Cookstove
173
Risha Mal, Rajendra Prasad, V.K. Vijay, Amit Ranjan Verma, Ratneesh Tiwari
25.
Low Cost Wind Turbines using Natural Fiber and Glass Fiber Composites
179
Rohit Rai Dadhich¹, Ramniwas Bishnoi², Virwal Pritamkumar K.³, Sanjeev Kumar
26.
Energy Security and Clean Use
185
Samarth Kohli, Sanjeev Kumar
27.
Structural and Photocatalytic Behaviour of TiO2
and α-Fe2O3-TiO2 Nanorods
194
Shanmugapriya P, Pandiyarasan V, Sanju Rani, Rajalakshmi N
28.
A Process Model to Estimate Biodiesel and Petro Diesel
Requirement and Mass Allocation Rule
201
Aprajita Chauhan, Shuchi Verma, Vinay K.Singh
29.
A Study of Select Aspects for Power Grid Corporation of India Ltd
212
Surbhi Gupta
30.
A Fully-Integrated Switched-Capacitor Voltage Converter
with higher Efficiency at Low Power
221
Swati Singh, Uma Nirmal
31.
Preparation of CuInS2 and In2S3 Thin Film for Thin Film Solar Cell
Application Using Chemical Spray Pyrolysis Technique
230
T Krishna Teja , Karthigeyan
32.
Study of Nanoporous Silica Aerogel Composite for Architectural
Thermal Insulation Application
237
Thanuja M Y, Karthigeyan
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Contents
33.
Potential of India for Ethanol as a Transportation Fuel
244
Vivek Pandey, Vatsal Garg, Niraj Singh, Deepak Bhasker, Partha Pratim Dutta
34.
Antenna Design and Optimization for RFID tag using Negative µ and ε Material
251
Shankar Bhattacharjee, Rajesh Saha, Santanu Maity
35.
Analysis of CDM Projects: An Indian Anecdote
259
Namita Rajput, Vipin Aggarwal, Ritika Ahuja
36.
Modeling and Simulation of Solar Cell Depending on
Temperature and Light Intensity
265
Shivam Dubey, Lipi Sarkar, Rishav Roushan, Santanu Maity
37.
Carbon Trading Scenario in India: A Business that
Works for Global Environment
273
Namita Rajput, Vipin Aggarwal, Ritika Ahuja
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
(v)
Protection of Load through Ferrite
Beads Using Marx Generator
Aman Jain1, Manish Pratap Singh2, Apoorv Shankar3, Vikram Kumar4
1
B-26, Manavsthali Apartments, Vasundhara Enclave, Delhi-110096
B-66/445, HWP Colony, Rawatbhata, Via Kota, Rajasthan-323307
3
D1-602, BPCL Colony, Sector-56, Noida, UP-201301
4
JSS Academy of Technical Education, Noida, UP
2
ABSTRACT
In this paper, two ferrite filters were designed. These filters were tested on a spectrum analyser.
Also, they were tested with a Marx Generator (5kV-50kV). These filters showed efficient
capability to protect the load from any unknown surge/spark.
1. INTRODUCTION
In 1989, Michael F. Stringefellow and John M. Wheeler invented a surge suppression circuit for
high frequency communication networks, having a primary line and a ground line. It included a gas
tube connected between the primary line and ground line, a bi-directional avalanche diode and one
or more ferrite beads connected in series between the primary line and ground line, and a metal
oxide varistor connected in series in the primary line.
In 2012, J. L. Kotny, X. Margueron and N. Idir introduced a high-frequency modelling method of
the coupled inductors used in electromagnetic interference (EMI) filters. These filters are intended
to reduce conducted emissions generated by power static converters towards the power grid.
The identification of the model parameters was based on the experimental approach. Simulation
results of the proposed model were compared to the experimental data obtained using the specific
experimental setup. These results made it possible to validate the EMI filter model and its
robustness in a frequency range varying from 9 kHz to 30 MHz.
In 1924, Erwin Otto Marx described an electric circuit called Marx generator. Its purpose is to
generate a high-voltage pulse from a low-voltage DC supply. Marx generators are used in high
energy physics experiments, as well as to simulate the effects of lightning on power line gear and
aviation equipment. The circuit generates a high-voltage pulse by charging a number of capacitors
in parallel, then suddenly connecting them in series.
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Aman Jain, Manish Pratap Singh, Apoorv Shankar, Vikram Kumar
Experimental Setup 1
FREQUENCY
GENERATOR
FERRITE
FILTER
CRO
Fig. 1: Block Diagram Representation of Ferrite Filter Circuit
Configuration 1: Single ferrite bead with two wound wire configuration of ferrite beads
connecting the positive terminal of function generator with one end of a wire on the bead and
connecting the other end of the other wire to the positive terminal of the CRO such that the ground
of function Generator and CRO were shorted along with the remaining ends of the two wires.
Fig. 2: Single ferrite bead with two wound wire.
Configuration 2: Tested the configuration of ferrite beads wherein one ferrite bead was connected
between the positive ends and the other connected
conne
between the ground ends of the function
generator and CRO.
Fig. 3: Single wire wound two ferrite beads in series.
Emerging Energy Technology perspectives-A
A Sustainable Approach - ISBN: 978-93-83083-73-2
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Protection of Load through Ferrite Beads Using Marx Generator
Experimental Setup 2
HIGH
VOLTAGE
POWER
SUPPLY
MARX
GENERATOR
FERRITE
FILTER
LOAD
Fig. 4: Block Diagram Representation of Setup to Test Filter Configurations
2. DESCRIPTION
High Voltage Power Supply: It is a small current high voltage power supply consisting of a 450v
inverter with an 18 stage voltage multiplier to get an output of about 7kV.
Fig. 5: High Voltage Power Supply
Here, the capacitors used are 100nF 400V film capacitors physically arranged like a ladder and 18
diodes connected in series. Supply from mains is first connected to 2MΩ resistance to limit the
current value to a minimum amount (0.11 µA). A 0.5mA fuse is connected for protection of the
circuit.
Marx Generator: Output from the power supply (7kV) is connected to the Marx generator. It is a
park generator consisting of 10 RC stages which are charged in parallel and discharged in series
thus producing a high voltage spark at each spark gap simultaneously.
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Aman Jain, Manish Pratap Singh, Apoorv Shankar, Vikram Kumar
Fig. 6: Marx Generator
Here 1MΩ, 2W, 500V carbon film resistors and 1nF, 4kV ceramic capacitors are used as RC pairs.
Also, two 4.7M, 350kV metal glazed resistors are used at the input side. These resistors have a
ballasting effect. They are used to prevent a continuous arc forming across the first gap, thus
preventing further firing of the Marx generator.
Ferrite Filter: Two configurations of ferrite filters are considered. These two are described above.
The spark from the spark gap is passed through this filter to the load.
Load: This is a simple circuit consisting of a bulb charged by a simple battery.
Result: In experimental setup 1 (Fig. 1) the input from frequency generator is passed through the
two configurations of ferrite filters and the result is seen at CRO.
When configuration 1(shown in Fig. 2) is used the CRO shows attenuation at high frequencies
which is maximum at 12.29 MHz (as shown in Fig. 7).When configuration 2 (as shown in Fig. 3) is
used the CRO shows attenuation at high frequencies which is maximum at 12.18 MHz (as shown in
Fig. 8).
Fig. 7: CRO output at 12.29 MHz for configuration 1
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Protection of Load through Ferrite Beads Using Marx Generator
Fig. 8: CRO output at 12.18 MHz for configuration 2
In experimental setup 2 (Fig 4) a Marx generator produces sparks through spark gaps. It is supplied
with a very high voltage dc supply of 5kV. The sparks produced are thrown on the test circuit
(load) through ferrite beads which acts as a filter.
The result of this setup is summarised below in Table 1.
Table 1: Summary of final result
POWER SUPPLY
[kV]
MARX
GENERATOR [ kV]
FILTER
LOAD
PROTECTION
5
50
Configuration 1
Yes
5
50
Configuration 2
Yes
3. CONCLUSION
Thus the two ferrite filters efficiently protected the load from the spark thus confirming that ferrite
beads can be used in electromagnetic compatibility applications.
There are various other fields where these filters can be used, including energy management
systems, computers, automatic lightning, AM radio equipment, factory automation equipment,
implantable medical devices, military/space electronic modules, radio controls, telecommunication,
television and monitors and various lab equipments.
REFERENCES
[1] Stringefellow F. Michael, Wheeler M. John Surge suppression circuit for high frequency communication
networks US Patent 1992; 5,124,873
[2] Kotny L. J, Margueron X, Idir N High-frequency model of the coupled inductors used in EMI filters
IEEE Transactions on Power Electronics, 2012; Volume: 27 Issue: 6
[3] E. Kuffel, W. S. Zaengl, J. Kuffel High voltage engineering: fundamentals, Newnes 2000
ISBN 0-7506-3634-3, pages 63, 70
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
5
Mechanically Autonomous System for Efficient Coach
Water Refilling in Indian Railways
Aman Kaushik
Near Khadi Bhandar, Fatwaria Mohalla
V.P.O.Beri, District-Jhajjar, Haryana-124201
ABSTRACT
Indian Railways is the biggest railway system in the world having more than 10000 trains and
115000 Km railway tracks. Amount of water wasted in Indian railways at various Water
Refilling Stations for more than 2000 trains, given the water flow rate (which generally fills one
tank of the coach in 340 seconds) is over 50000 cubic meter or 1.3 million gallons per day. Here
a small and cheap SELF CLOSING refilling mechanism is devised with estimated cost of Rs.50
that fits with existing system that is present at all the refilling stations across our country. This
mechanism consists of a pipe (7cm long) having a Lid inside it that opens up opposite to the
water flow by leverage function provided by a steel wire. This wire runs parallelly with the
rubber pipe that is attached to the coach of the train. The worker just need to pull this wire and
attach it to a specially designed hook at the coach inlet which provides the constant holding
force responsible for opening of Lid against high pressure of water. As soon as train moves or
tank is filled, this hook detaches INSTANTANEOUSLY from the wire causing Lid to close. This
detachment does not depend upon the movement of direction of the train i.e. it will work when
the train moves forward or backward also. In addition the same mechanism will be able to save
thousands of liter of water wasted in refilling stations/junctions from where the train starts also
(i.e. train is fully filled with water before running). This process wastes more water while
refilling in mid-journey. Thus water leakage is prevented till the worker arrives to close the valve
(ultimately conserving millions of gallons of water per day). Thus this self-closing mechanism is
cheaper and very efficient for our railways.
Keywords: Conservation, Wastage, Water, Railways, Environment, Water Pollution
1. INTRODUCTION
Indian Railways is the biggest railway network in the entire world. We have more than 10000
trains running on 115000 Km railway tracks. Approximately 2000 trains run over distances of more
than 1000 Km. These are the trains which consume maximum quantity of water during the journey
as refilling is mandatory for such trains. The amount of water wasted during these refilling is more
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Mechanically Autonomous System for Efficient Coach Water Refilling in Indian Railways
than 50000 cubic metre or 1.3 million gallons per day, given the water flow rate used for refilling
the train (which generally fills one tank of the coach in 340 seconds).
This makes Indian railways the biggest consumer of fresh water and also the source of its wastage.
2. MAIN REASONS OF WATER WASTAGE WHILE RE-FILLING:
Figure 1
There are primarily three main reasons for this wastage of watera) Less personnel to operate refilling. Normally only 3 or 4 personnel are allotted to do this work.
The general configuration of such long route trains is shown in Table-1 followsTable-1
So it is very much difficult for three persons to cover 467m long train.
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Aman Kaushik
b) Carelessness of personnel responsible for refilling
c) Unfavorable conditions for fast response (Walking fast on Sleepers is very difficult)
3. COACH CONFIGURATION
The capacity of a normal Indian Coach Factory coach is 500L per tank as shown in the Figure-2:
Figure-2
A coach has four of these tanks (so the total capacity is 2000L per coach). Time required to fill one
coach in mid-journey is between 3 and 4 minutes depending upon the flow of water (varies
continuously). While the time required for filling the coach while shunting or before staring is
between 15 and 20 minutes.
4. SOLUTION
Design a self-closing mechanism which is independent of all the above stated problems and fully
autonomous and that fits with the existing setup of Indian Railways. The main working principle is
as shown in Figure-3:
Figure-3
Figure-4
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Mechanically Autonomous System for Efficient Coach Water Refilling in Indian Railways
Add an extra pipe assembly to the valve of the existing pipe of the shape as shown in Figure3.Here
this assembly contains a LID which opens up against the flow of the water while refilling. For
refilling to be done, we need a large holding force for the LID in this position against the huge
force of water that is trying to close this LID down thus blocking the flow of water. It is done using
an additional wire which is connected to this LID as shown in Figure-4. This additional wire runs
parallel with the main pipe which is connected to the coach inlet pipe on other end. Now first of all,
this main pipe is attached to the coach inlet and the additional wire that runs parallel to the refilling
pipe is hooked up using a rod to a specially designed groove on the coach inlet pipe as shown in
Figure-5.
Figure-5
Figure-6
The shape of this groove is designed such that it will detach the rod that runs parallel with the
refilling pipe and in turn stop the water flow as soon as the train moves in any direction i.e. whether
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Aman Kaushik
forward or reverse. The whole system can be understood from Figure-6, where the location of each
and every part is shown is a confined space.
This solves one half of the problem i.e. when the train is refilled in mid-journey. Now for the cases
when the train is refilled before starting, a new problem arises i.e. there are many times when the
tank is full with water and starts over-flowing till the time the responsible person comes and closes
the valve. The solution of this problem is shown in Figure-7.
Here the On-Off Float type methodology is used to stop the flow from refilling pipe. As the level of
water rises inside the tank, the float rises and thus pulls the wire that is connected with the hook or
the groove. The inner shape of this hook or groove and its working methodology is as shown in
Figure 8:
Figure-8
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Mechanically Autonomous System for Efficient Coach Water Refilling in Indian Railways
So with the above mentioned techniques, all the water wastage problem while refilling the train can
be solved.
Material Specifications: a) Lid- Steel/Aluminium alloy
b) Additional Wire- Steel
c) Float for tank-Plastic
d) Pulleys- Plastic/wood
Main Features: a) Self Closing of fully autonomous.
b) Compatible with existing system of Railways.
c) Fully mechanical (any worker can tinker and modify according to need in non-availability of
material in order to avoid wastage during that time)
d) Very simple working (easy for non-trained people also, no need of extra training).
e) Fully efficient in saving water throughout the country.
Advantages: a) Very cheap (can be manufacture within Rs.70)
b) Easy to manufacture and install.
c) Rugged construction which is fit for public use and can sustain rough man-handling.
d) Eco-friendly system.
e) Highly efficient.
REFERENCES
[1] Alexander Vorontsov, Vasily Volokhovsky, Igor Morin: Strength assessment of working capacity of
steel wire ropes.
[2] Siniga Dunda and Trpimir Kujundzic: Tensile strength of steel ropes of diamond wire saws.
[3] Seok-Myeong Jang, Jang-Young Choi, You, Dae-Joon, Han-Wook Cho: The influence of mechanical
spring on the dynamic performance of a moving-magnet linear actuator with cylindrical Halbach
array, Industry Applications Conference, 2005. Fourtieth IAS Annual Meeting. Conference Record of
the 2005, 2132 - 2139 Vol. 3, 0197-2618
[4] Information on www.indianrailways.gov.in
[5] Information on www.wikipedia.com
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Performance Analysis of Hybrid Solar
Photovoltaic-Thermal Collector
Amit Verma, Sunita Chauhan
1
School of Renewable Energy and Efficiency, NIT Kurukshetra, India
*Electrical Engg. Deptt., NIT Kurukshetra, India
ABSTRACT
The idea of combining photovoltaic and solar thermal collector to provide electrical and heat
energy is not new, however it is an area of limited attention. Hybrid photovoltaic-thermal‘s have
become a focus point of interest in the field of solar energy. Integration of both (Photovoltaic
and thermal collector) provide greater opportunity for the use of renewable solar energy. This
system converts solar energy into electricity and heat energy simultaneously. Theoretical
performance analyses of hybrid PV/T’s have been carried out, also the temperature of water (as
a heat carrier) have been calculated for different seasons.
Keywords: Solar energy; Photovoltaic-Thermal; Seasonal performance Analysis
1. INTRODUCTION
Solar energy is one of renewable energy sources which have potential for future energy application.
Solar energy can generally be divided into two parts-The Photovoltaic technology which derived
from solar cell and convert into electricity and Thermal solar technology which derived from the
thermal collector and convert the solar energy into heat. Photovoltaic solar cells capable of
changing some part of solar energy into electricity while the rest of the solar energy become
waste[1].For both theoretical and practical reasons ,not all of the solar radiation energy falling on a
solar cell can be converted into electrical energy. A specific amount of energy is required to
produce a free electron and a hole in the semiconductor material .For example, in silicon the energy
minimum is 1.1 eV and this is available in radiation having a wavelength of 1.1 micrometer.
Consequently infrared radiation of longer wavelength has no photovoltaic effect in silicon but is
largely observed as heat .Energy in excess of that needed to free a bound electron is simply
converted into heat. The efficiency of the heated photovoltaic panel that exposed to sunlight will be
decreased [6]
The latest research in this field of solar energy was to gain heat energy and decrease the
temperature of photovoltaic panel simultaneously. Electrical energy and heat energy are collected
separately. Photovoltaic-thermal collectors are to design to collect heat. If the temperature will
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Performance Analysis of Hybrid Solar Photovoltaic-Thermal Collector
reduce then definitely the efficiency of PV will increase. Water or air can be used as heat carrier.
Here we used the water. This warm water can be further used for low temperature application.
Florschetz suggest a model propose by Hottel-Whillier to analysis PV/T system [2].Bhargava [3]
and Prakash[4] reported on effect of mass flow rate, air ducting sizing and the width of collector
absorber used to the performance of the PV/T system.
Othman [5] reported the double pass PV/T collector with fins absorber shows better performance.
The objective of this paper to increase the efficiency of the PV module as well as used the waste
heat for low temperature application.
Experimental Set-up
The setup consists of the water based Spiral flow PV/T collector generates electricity and produce
hot water simultaneously. The water based PV/T collector consists of spiral type tube upper part of
which consists photovoltaic cells, as the absorber gets heat up this heat will be absorbed by the
water by the conduction and it can increase the efficiency of the collector .The schematic diagram
and specification of the spiral flow type Photovoltaic-Thermal collector is shown in fig.1 and table
1
Area of PV/T
PV Cells
1×1=1m
2
Cool
Water in
Warm
out
Fig.1 Schematic dia. of Spiral-flow PV/T
Max Power (Pmax)
Open Circuit Voltage(Voc)
Max Power current(Ipm)
Efficiency (ῆ)
Solar Radiation =1000 W/m-
80W
21 V
4.63 A
8%
2
Cell temperature = 25oC
Table 1: Specification of PV/T collector
2. PERFORMANCE ANALYSIS
In order to assess the system’s performance, we should know the average solar insolation. This can
be found using the following formula [7];
Avg. Solar Irradiance = Normal solar irradiance (1367 W/m²) × cos (z)
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
(1)
13
Amit Verma, Sunita Chauhan
Where,
Cos (z) = sin δ sin φ + cos δ cos φ cos [(LAT- 12) ×15]
(2)
δ = 23.45 sin [(360/365) × (284+n)]
(3)
Where, n= no. of days
LAT = Standard time ± 4(Standard time Longitude – longitude of location) + (equation of time
correction)
(4)
Location of Kurukshetra is 29.96°N, 76.83°E. The average values of solar insolation for this
location using the above formula for various seasons are calculated.
Seasons
Summer (Mar-Jun)
Monsoon (Jul-Sep)
Winter (Dec-Feb)
Avg. Solar Irradiation (W/m²)
9:00 to
11:00 to 13:00
11:00
1027.61
1231.35
854.5
1064.3
634.38
839.38
13:00 to 15:00
1133.16
943
758.82
Table 2: Value of Avg. solar irradiation for different seasons in different time periods
To find the total heat available to the PV/T in summer (March-June) for time period 9:0011:00 a.m:
A = 1×1 = 1 m²
Q = Ib rb × A = 1027.61 W
(5)
This is the amount of power available to the PV/T collector. PV cells convert only 8% of this
power into electricity; the remaining power available in the form of heat and this heat increase the
temperature of PV/T .increasing temperature decrease the efficiency of the PV cell .To maintain the
temperature at the normal ambient temperature we can extract this heat from PV by the use of
water as heat carrier
We can determine the temperature of warm water also as.
Q´ = 1027.61×0.92 = 945.4 W
This is the amount of heat available to the absorber. Using this heat for 2 hours i.e. 9:00-11:00 a.m.
for 2.8 Kg of water at 35°C (room temperature of water in summer), we can determine the
temperature of warm water attained in the system [8];
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
14
Performance Analysis of Hybrid Solar Photovoltaic-Thermal Collector
Q´ = mass of water× [Cpw (100-Tw) + Latent heat of vaporization + Cps (Ts - 100)] / (2×60×60) (6)
945.4 = {2.8×1000[4.18 (100-35) + 2257 + 2 (Ts – 100)]} / (2×60×60)
Therefore, Ts = 51.1°C
For summer in 11:00a.m-13:00p.m time period, here we used the 3.3 Kg of water
Ts = 71.4°C
For summer in 13:00p.m-15:00p.m time period, here we used the 3.1Kg of water
Ts = 46.2°C
In a similar way, Ts can be found for monsoon and winter season to ascertain the steam
temperature. However, in case of monsoon season (July-September), the room temperature of
water is taken as 25°C and 10°C for winter season (December-February).
3. CONCLUSION
Thus, from the table below we can conclude that maximum solar intensity is received during
summer season and also, the amount of warm water obtained highest in this season.
And it will also increase the efficiency of the PV cells by extracting the extra heat from the panels
through the water as heat carrier.
Table 3 Various Values of PV power and temperature of water at different season
Summer(Mar-Jun)
Monsoon(Jul-Sep)
Winter(Dec-Jan)
9:00-11:00 11:0013:00
13:0015:00
9:0011:00
11:0013:00
13:0015:00
9:0011:00
11:0013:00
13:00-15:00
1027.61
1231.35
1133.16
854.5
1064.3
943
634.3
839.38
758.82
Total power 1027.61
available
to
PV panel (W)
1231.35
1133.16
854.5
1064.3
943
634.3
839.38
758.82
Q´ (Watts)
1132.84
1042.5
786.1
1065.2
867.56
583.6
772.22
698.11
Mass of water 2.8
(Kg)
3.3
3.1
2.3
3.1
2.6
1.7
2.2
2
Temp.
of 51.1
warm
water
(Ts in °C)
71.4
46.2
45.1
51.7
16
19.2
47
38
Avg.
Irradiance
(W/m²)
945.4
Avg. temp. of 56.2
warm
water
(Ts2 in °C)
37.6
34.73
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
15
Amit Verma, Sunita Chauhan
4. NOMENCLATURE
Cpc = Specific heat of coolant, KJ/Kg °C
Cps = Specific heat of steam, KJ/Kg °C
Ts = Temperature of steam, °C
Cpw = Specific heat of water, KJ/Kg °C
Tw = Temperature of water at room temperature, °C
Z = Zenith angle
δ = Declination angle
Φ = Latitude
LAT = Local Apparent Time (hours)
Ib = Beam Radiation, W/m2
rb = Tilt factor
A = Area of PV/T panel, m2
Q = Heat incident on PV/T collector, Watts (W)
Q΄ = Heat received by the absorber tube, Watts (W)
REFERENCES
[1] Othman M Y, Ibrahim A, Ruslan M H, Sopian K, 2013 “ Photovoltaic-thermal (PV/T) – The future
energy technology”, Renewable Energy Vol. 49,pp. 171-174
[2] Cox CH, Raghuraman P. Design considerations for flat-plate photovoltaic/thermal collectors. Solar
Energy 1985; 35:227.
[3] Bhargava AK, Garg HP, Agarwal RK. Study of a hybrid solar system- solar air heater combined with
solar cell. Solar Energy 1991; 31(5):471
[4] Prakash J. Transient analysis of a photovoltaic-thermal solar collector for co-generation of electricity&
hot air/water. Energy Conversion Management 1994; 35(11):967
[5] Tonui JK, Tripanagnostopoulos. Performance improvement of PV/T solar collectors with natural air flow
operation. Solar Energy 2008; 82(2008).
[6] G.D.Rai,”Non-conventional sources of energy “Khanna Publisher, fourth edition, pp-178-190
[7] S.P. Sukhatme, 1996, “Solar Energy-Principles of thermal collection and storage”, Tata McGraw-Hill
Publishers, Second Edition, pp. 74-93
[8] Sharma S.D., Buddhi D., Sawhney R.L., Sharma A., 2000, “Design, development and performance
evaluation of a latent heat storage unit for evening cooking in a solar cooker”, Energy Conversion and
Management, Vol. 41, pp. 1497-1508.
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
16
Design and Implementation of SPWM and
Hysteresis based VSI Fed Induction Motor
Amruta Pattnaik1, Haymang Ahuja1, Shubham Mittal2, Nisha Kothari3, Tushar Sharma4
1
EEE, NIEC, FC-26, Shastri park, Delhi-53
B.Tech, EEE, NIEC, FC-26, Shastri Park, delhi-53
1,2,3,4
ABSTRACT
This paper deals with the performance analysis of three phase induction motor drive fed by a PWM
voltage source inverter. Here we are using two types of (PWM) techniques, one is sinusoidal pulse
width modulator (SPWM) and another one is hysteresis band pulse width modulation (HBPWM)
techniques. This paper work deals mainly with the performance analysis of three phase induction
motor fed by PWM voltage source inverter in terms of phase current of inverter, rotor and stator
current , speed ,electromagnetic torque developed and total harmonic distortion in line and phase
voltage of inverter .For the implementation of the proposed drive the MATLAB/SIMLINK
environment has been used. There so many types of PWM techniques, in which SPWM and
HBPWM are one of them. The HBPWM approach has been selected for the research, since it has
the potential to provide an improved method of deriving non-linear models which is
complementary to conventional techniques. And the SPWM method, which involves the
modulation of conventional sinusoidal reference signal and a triangular carrier signal, is used here
to produce pulse width modulated output. The performance analysis of the inverter has been done
using the parameter total harmonic distortion implemented with help of FFT block.. The impact of
the PWM techniques on the performance of the inverter fed to an induction motor has been done in
terms of the waveforms for inverter phase voltage, line voltage, line current, stator current, rotor
current, rotor speed and electromagnetic torque developed by the motor.
Keywords: Induction Motor (IM) drive, MATLAB/SIMULINK, VSI, sinusoidal pulse width
modulation (SPWM), hysteresis Pulse Width Modulation, THD.
1. INTRODUCTION
Power electronic has changed rapidly during the last thirty years and the numbers of application
has been increasing, mainly due to the development of the semiconductors devices and the
microprocessor technology.[1]The dc-ac converter, also known as the inverter. The filter capacitor
across the input terminals of the inverter provides a constant dc link voltage. The inverter therefore
is an adjustable-frequency voltage source. The configuration of ac to dc converter and dc to ac
inverter is called a dc- link converter.[2]
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
17
Amruta Pattnaik, Haymang Ahuja, Shubham Mittal, Nisha Kothari, Tushar Sharma
Three phase induction motors are widely used motors for any industrial control and automation. It
is often required to control the output voltage of inverter for the constant voltage /frequency (V/F)
control of an induction motor.[2] PWM (pulse width modulation) based firing of inverter provides
the best constant of an inductor motor. Amongst the various PWM techniques, the sinusoidal PWM
and hysteresis band PWM are one of them.
In this paper we analysis the performances of induction motor in open loop. Here we used three
phase voltage source inverter which is SPWM and hysteresis PWM techniques with power IGBT is
described.[7]
2. INVERTER
Power inverter are devices which can convert electrical energy of DC from into that of AC.
Inverters can be broadly classified into two types based on their operation :
1.
Voltage Source Inverter (VSI)
2.
Current Source Inverter (CSI)
A voltage source inverter is commonly used to supply a three-phase induction motor with variable
frequency and variable voltage for variable speed applications. A voltage fed inverter (VFI) or
more generally a voltage source inverter (VSI) is one in which the dc source has small and
negligible impedance. [fig.1].The voltage at the input terminal is constant. A current source
inverter is fed with the adjustable current from dc source of high impedance that is from a constant
dc source. A voltage source inverter employing thyristor as switch, some types of forced
commutation is required ,while the VSI made up of using GTO’s, Power transistor, power
MOSFET or IGBT self commutation with base or gate drive signal for their controlled turn ON and
turn OFF.[2].
Figure1: Two Level Six Pulse Inverter
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Design and Implementation of SPWM and Hysteresis based VSI Fed Induction Motor
PWM Techniques Used To Implement
nt Inverter
Pulse width modulation is a technique in which a fixed input dc voltage is given to the inverter and
a controlled ac output voltage is obtained by adjusting the ON and OFF periods of the inverter
components. This is most popular methods of controlling the output voltage and this
thi method is
termed as the pulse width modulation technique.[6] PWM is an internal control methods and it
gives better results than an external control methods. There are number of PWM methods for
variable frequency voltage -sourced
sourced inverter. A suitable PWM technique is employed in order to
obtain the required output voltage in the side of the inverter [2]. There are many effective
techniques used to implement the three phase inverter is the Pulse Width Modulation Technique.[7]
Here we are using two types of PWM techniques as given below.
1.
Sinusoidal pulse width Modulation(SPWM)
2.
Hysteresis band Pulse Width Modulation(HBPWM)
1. Sinusoidal Pulse Width Modulation
In sinusoidal PWM three phase reference modulating signal are compared against a common
triangular carrier to generate the PWM signals for the three phases as per diagram given below [fig
2].
Fig 2. SPWM waveforms
A Sinusoidal Pulse Width Modulation technique is also known
kno as the triangulation, sub oscillation,
sub harmonic method, is very popular in industrial applications.[5] In this technique a high
frequency triangular carrier wave is compared with the sinusoidal reference wave determines the
switching instant. When the
he modulating signal is a sinusoidal of amplitude Am, and the amplitude
Emerging Energy Technology perspectives-A
A Sustainable Approach - ISBN: 978-93-83083-73-2
19
Amruta Pattnaik, Haymang Ahuja, Shubham Mittal, Nisha Kothari, Tushar Sharma
of triangular carrier wave is Ac, then the ratio m=Am/Ac, is known as the modulation index. It is to
be noted that by controlling the modulation index one can control the amplitude of applied output
voltage.[10]
2. Hysteresis band Pulse Width Modulation
The basic principle of HB PWM technique is that the sinusoidal reference of desired magnitude and
frequency is compared with the triangular signal of fixed width hysteresis band. For hysteresis
control the phase output current is fed back to compared with the reference current iref. An upper
tolerance band and lower tolerance band, taken as +/-0.5% of, iref also assigned in order to define an
acceptable current ripple level. Whenever the phase current exceeds the upper band, the upper
switch of that leg will be turned ON while the lower switch will be turned OFF. If phase current
falls below the lower band, the upper switch will be turned OFF whereas the lower switch will be
turned ON[11 ].The hysteresis band PWM has been used because of its simple implementation, fast
transient response, direct limiting of device peak current and practical insensitivity of dc link
voltage ripple that permits a lower filter capacitor[11]
Three Phase SPWM and Hysteresis band Induction Motor Drive
Three phase voltage fed PWM inverters are growing very rapidly for many drive applications such
as megawatt industrial drive etc. The main reason for using this drive is that the large series voltage
between the devices is shared and improvement of the harmonics quality at the output as compared
to the two level inverter. Now- a -days GTO devices replaced by IGBTs because of their rapid
evolution in voltage and current ratings and also higher and better switching frequency [1]. In most
variable speed drives PWM VSI are used. Usually machine design tools only consider the
fundamental harmonics of the starter voltage when calculating the losses. These losses are caused
by harmonics of the voltage and the current due to the PWM. A number of algorithms for PWM
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
20
Design and Implementation of SPWM and Hysteresis based VSI Fed Induction Motor
voltage generations are discussed are present. Here we are using SPWM and hysteresis band PWM
technique based voltage source inverter fed to an induction motor and compare the performance of
both types of PWM technique in open loop.[4] The result has been given in fig [7] & [8].
Analysis of Three Phase PWM VSI
Simulation is done on a three phase induction motor fed by a PWM inverter developed in
MATLAB /SIMULINK environment. The fig 4. Shows the SIMULINK diagram of the developed
model. The basic circuit of the proposed scheme consist of a three phase induction motor as wound
rotor type having ratings 3HP, 240V, 50Hz. The three phase induction motor drive is fed by three
phase PWM based VSI inverter. For VSI we are using six IGBT switches in a bridge form and fed
by DC voltage of 300V.
Discre te ,
Ts = 5e-005 s.
g
C
g
E
T5
E
T3
E
T1
C
C
g
po wergui
Out1
Out2
Out3
Scope
<Rotor current ir_a (A)>
Out4
g
C
C
E
i
-
<Rotor current ir_c (A)>
<Stator current is_a (A)>
C urrent Measurement2
<Stator current is_b (A)>
E
g
C
+
T2
T6
E
T4
Out6
g
<Rotor current ir_b (A)>
Out5
<Stator current is_c (A)>
<Rotor speed (wm)>
Subsystem
<Electromagnetic torque Te (N*m)>
Tm
11.9
Constant
m
A
a
B
b
C
c
Asynchronous Machine
SI Units
+ v
-
Voltage Measurement2
-Krpm
Figure4: Simulink Model for SPWM and Hysteresis PWM Based VSI Fed Induction Motor
Generation of Gating Pulses By SPWM
The gating pulses for the six IGBTs of three legs are generated. The generation of these pulses is
carried out by sinusoidal pulse width modulation technique as per fig [5].
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
21
Amruta Pattnaik, Haymang Ahuja, Shubham Mittal, Nisha Kothari, Tushar Sharma
Generation of Gating Pulses By HB PWM
The gating pulses for the six IGBTs of three legs are generated. The generation of this pulses is
carried out by hysteresis band pulse width modulation technique as per fig [6].
Figure 6: Simulink Model of Generating Of Gating Pulse By HBPWM
Convert
1
1
Out1
Da ta T ype Conversi on6
Con vert
Rel ay
Da ta T ype Conversi on
NOT
Convert
L ogi cal
Ope rator1
Da ta T ype Conversi on3
Out2
Co nvert
Con vert
Out1
2
4
3
3
Out3
Data T ype Co nve rsi o n7
Out2
Re l a y1
Data T ype Co nversi on 1
Out3
NOT
Co nvert
Out4
4
6
Out4
Logi ca l Data T ype Co nve rsi o n4
Operator
Su bsystem
Con vert
Rel ay2 Data T yp e Conversi on2
5
5
Ou t5
Data T ype Con versi on 8
Conve rt
NOT
Con vert
Logi ca l
Op era to r2
Data T ype Con versi on 5
6
2
Ou t6
Simulation Results of the SPWM AND HB PWM Fed Induction Motor Drive
Results are obtained by simulating the circuit. Here we analyse SPWM and HB PWM motor and
inverter performance
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
22
Design and Implementation of SPWM and Hysteresis based VSI Fed Induction Motor
Comparison Of THD Of Line Current For SPWM AND HB PWM Techniques
Table:1 Comparison of VSI voltage and current of SPWM and HysteresisPWM technique
S. No.
PWM Techniques
Line Current THD
(%)
Line Voltage THD
(%)
1
SPWM
8.26
31.97
2
HB PWM
4.71
31.98
3. CONCLUSION
The paper presents performance analysis of three phase induction motor fed by PWM voltage
source in under modulating range. For this purpose the MATLAB/SIMULINK approach has been
used for the implementation of the proposed drives. The three phase inverter has been
implemented. The performance analysis of the inverter has been done using the parameter total
harmonic distortion implemented with help of FFT block. The THD has been calculated for the line
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
23
Amruta Pattnaik, Haymang Ahuja, Shubham Mittal, Nisha Kothari, Tushar Sharma
current and line voltage [table 1] . The main advantage of this approach is that it shows the
performance of the motor as well as of the voltage source inverter based on different PWM
techniques. There is appreciable improvement in THD in inverter line current in HB PWM
technique, as compared to SPWM technique as given in table 1.
The motor speed is zero initially and increased to the final value as the time increase. Initially the
electromagnetic torque developed by the motor is highly oscillatory and after the transient time it
settles down to the vale which is equal to the load torque.
REFERENCES
[1] Sharma A.K,Saxen ,DTushar, Islam Shirazul&Yadav.Karun, “performance Analysis Of Three Phase
PWM Voltage Source Inverter Fed three Phase Induction Motor Drive”, International Journal of
Advance Electrical and Electronics Engineering(IJAEEE) 2013.
[2] Sharma C.S, NagwaniTali, “Simulation and Analysis of PWM Inverter Fed Induction Motor Drive”,
International Journal of Science, Engineering and Technology Research (IJSETR)” , February 2013.
[3] Zope H Pankaj, Bhangle G Pravin, Sonare Prashant, Suralkar S.R “Design and Implementation of carrier
based Sinusoidal PWM Inverter” ,(IJAEEE) October2012.
[4] Houdsworth J.A and Grant D.A, “The use of Harmonics distortion to increase output voltage of a three
phase PWM inverter” , IEEE Trans. Industry Appl., vol. IA-20, pp. 1124-1228, sept./oct. 1984.
[5] “Performance of Sinusoidal pulse Width Modulation based three phase inverter “. International
Conference on Emerging Frontiers in Technology for Rural Area (EFITRA) 2012 Proceedings published
in International Journal of Computer Application (IJCA).
[6] Kazmierkowski M.P., Krishnan R., and Blaabjerg F.,”Control in power electronics selected problem” ,
Academic Press, California, USA. 2002.
[7] Kerkman R.J., Seilbel B.J., Bord D.M. , Rowan T.M. , and Branchgate D. ,”A Simplified inverter model
for on-line control and simulation, IEEE Trans. Ind. Applicant., Vol. 27, NO. 3, pp.567-573. 1991.
[8] Dong G., “Sensorless and efficiency optimized induction motor control with associated converter PWM
schemes” ,phD Thesis, Faculty of Gradute School, Tennessee technological University, Dec.2005.
[9] “Modeling and Simulation of Modified Sine PWM VSI Fed Induction Motor Drives.” International
journal of Electrical Engineering & Technology, Vol.3, Issue 2, July- September 2012.
[10] “Understanding FACTS: concept and technology of flexible AC transmission system “, by Narain G.
Hingorani, LaszolGyugyi.
[11] “MODERN POWER ELECTRONIC AND AC DRIVES”, by Dr.Bimal K. Bose, publication year.2001.
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
24
A Comparative Study on TiO2and SiOx Dielectric
based MOS Capacitance
Ashik Some1, Diksha Barnwal1, Arnab Shome1, Birojit Chakma1, Lalaram Arya1,
B.S. Thoma1, Aniruddha Mondal1
1
Dept. of Electronics & Communication Engineering, NIT Agartala, Jirania, Tripura, 799046
ABSTRACT
The TiO2 and SiOx dielectric based n-MOS and p-MOS devices were fabricated by using e-beam
evaporation technique on Si <100> substrates (33.5 Ωcm for n-Si and 30 Ωcm for p-Si). The
TiO2 and SiOx (99.999% pure, MTI USA) have been evaporated to fabricate the 50 nm thin films
(TF) on the Si substrates. The deposition rate was kept constant at 1.2 Ao/s for both TiO2 and
SiOx material. The upper electrodes of diameter 1.5 mm were made of silver (Ag) and aluminium
(Al) metal on TiO2 and SiOx thin film (TF) respectively. The Capacitance-Voltage (C-V)
measurements were carried out on the TiO2 and SiOx based MOS devices using LCR meter
(HIOKI, 3532-50). The maximum accumulation capacitance of 7.4 pF and 6.5 pF were
measured for TiO2 based n-MOS and p-MOS respectively at 1 MHz. The carrier concentration
of 5.9 × 1018/m3 for n-Si/TiO2 TF/Ag device and 1.29 × 1021 /m3 for p-Si/TiO2 TF/Ag device were
calculated. The accumulation capacitance of 5.0 pF was measured for SiOx based p-MOS device
and the carrier concentration was measured 1.5 × 1019 /m3. Finally, compared to SiOx MOS
device the TiO2 based MOS device has larger capacitance, which may reduce the device leakage
current. Therefore, the TiO2 based high dielectric material may allow the device shrinking
process for the fabrication of modern devices.
Keywords: MOS, TF, Schottky Contact, Ohmic Contact, TiO2, SiOx
1. INTRODUCTION
With the advancement in technology, the downscaling of devices is increasing the leakage current
[1] and with continuing decrease of the gate dielectric thickness in conventional silicon MOS
devices. The thin dielectric layer reduces the Vth which results in an increase of leakage current [2].
The simple relationship between the thickness of dielectric (d) and oxide capacitance (Cox),
d= ῆA/Cox
(1)
does not hold for thin oxides. Lot of techniques have been employed to reduce the device leakage
current [3,4]. A common technique of using high dielectric thin oxide increases the capacitance and
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
25
Ashik Some, Diksha Barnwal, Arnab Shome, Birojit Chakma, Lalaram Arya, B.S.Thoma, Aniruddha Mondal
hence decreases the leakage current. The Schottky contact on the high dielectric oxide layer again
decreases the leakage current compared to Ohmic contact [5]. In case of thin oxide layer, it is very
difficult to measure the device capacitance at lower frequencies due to presence of noise [6].
Therefore, the higher frequencies are preferable to characterize the thin oxide layer based MOS
devices. Also, Capacitance (C)–Voltage (V) measurement technique is a powerful technique to find
out the MOS device quality for further improvements. This aforementioned method can be used to
calculate the important parameters like carrier concentration (Nb), flat band voltage (Vfb) as well as
other parameters easily.
In this report we have fabricated the n-MOS and p-MOS devices by using high dielectric TiO2 and
low dielectric SiOx oxide layer as gate oxide on Si substrate. The contacts were made Ohmic for i)
n-Si/SiOx TF/Al contact (p-MOS), and Schottky for ii) n-Si/TiO2 TF/Ag contact (p-MOS), iii) pSi/TiO2 TF/Ag contact(n-MOS) devices. The use of Schottky contact based devices lead to
decrease in leakage current compared to Ohmic contact devices in which tunneling occurs [7,8].
The room temperature C-V was measured for the devices and compared. The flat band voltages
(Vfb) and carrier concentration (Nb) were also calculated.
2. EXPERIMENTAL SECTION
The MOS devices were fabricated on 1cm×1cm cleaned p-type and n-type Si<100>substrate inside
e-beam evaporator at a base pressure of 10-5mbar. High purity TiO2 TF and SiOx TF (99.999%
pure, MTI USA) of thickness 50 nm were deposited separately on two substrates n-Si and p-Si at a
constant deposition rate of 1.1-1.2 A°/s. Silver (Ag) and Aluminum (Al) are deposited as the gate
electrode through Aluminium (Al) mask hole, having an area of 1.77×10-6 m2 on TiO2 TF and SiOx
TF respectively. The capacitance through the devices were measured by using LCR meter (HIOKI,
3532-50).The carrier concentration was calculated from 1/C2 v/s V graph and flat band voltage
(Vfb) obtained directly from C-V curve.
3. RESULTS AND DISCUSSIONS
Fig. 1 shows the graphs of C-V measurement for the three fabricated MOS devices done at
frequency 1MHz at room temperature with the help of LCR meter (HIOKI, 3532-50). It can be
seen from C-V curves of 50nm TF (Fig. 1) that the measured capacitance is dependent on both
frequency and bias voltage. Each curve has three different regions of accumulation, depletion and
inversion with a considerable shifting of voltage axis towards the negative bias due to the presence
of interface states which is in equilibrium with semiconductor [9]. AC measuring signal frequency
(1 MHz) is so high that the inversion layer charge Qi cannot follow high frequency (HF) variation
w.r.t changes in gate voltage (Vg) and thus assumed to be constant for a given DC bias [10]. The
gate capacitance (Cg) in inversion at HF becomes
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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A Comparative Study on TiO2and SiOx Dielectric based MOS Capacitance
Cg= (
+
-1
) .
(2)
Cg given by this equation is Cmin at HF. The flatband (Vfb) voltages shown in the graphs have been
calculated by using equations Debye length,
λD = (3)
and flatband capacitance,
CFB=
/
/
(4)
Where Nb is the calculated carrier concentration [11], shown in Table1.
50 nm
Dielectric (TiO2 or SiOx) TF
4.5
Cp (pF)
150 nm
p-Si/ SiOx TF(50 nm)/ Al contact (150 nm) at 1 MHz
5.0
Metal (Ag or Al)
contact
4.0
3.5
(a)
Si (n or p type) substrate
Vfb = 5.5 volt
(b)
3.0
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0
1 2
3
4 5
6 7
8
9 10
Volts
7.5
n-Si/ TiO 2 TF (50 nm)/ Ag contact (150 nm) at 1 MHz
6.5
p-Si/ TiO2 TF (50 nm)/ Ag contact (150 nm) at 1 MHz
6.0
Cp (pF)
Cp (pF)
7.0
6.5
5.5
(c)
Vfb = -2 volt
5.0
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10
Volts
(d)
Vfb = 8.5 volt
6.0
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10
Volts
Fig. 1. a) Schematic diagram of fabricated MOS device. Capacitance versus voltage
characteristics at 1MHz frequency for b) n-Si/SiOx TF/Al contact (p-MOS), c) n-Si/TiO2
TF/Ag contact (p-MOS), d) p-Si/TiO2 TF/Ag contact (n-MOS)
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
27
Ashik Some, Diksha Barnwal, Arnab Shome, Birojit Chakma, Lalaram Arya, B.S.Thoma, Aniruddha Mondal
Fig. 2 shows the 1/C2 v/s V characteristics. These characteristics have been used to find the carrier
concentration. The concentration (Nb) is given by
Nb=
×
× ×
(5)
where the dielectric permittivity (ῆr) of SiOx is 3.9 and of TiO2 is 80 [12] and m is the slope
obtained from 1/C2 v/s V characteristics graphs. Three readings of Nb are obtained for three
different values of slopes and their average is done to obtain final values for each graph.
0.10
n-Si/ SiOx TF (50 nm)/ Al contact (150 nm) at 1Mhz
n-Si/ TiO2 TF (50 nm)/ Ag contact (150 nm) at 1 MHz
0.035
1/(C^2)
1/(C^2)
0.08
0.06
0.04
0.030
0.025
(a)
(b)
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10
Voltage(Volts)
Voltage(Volts)
p-Si/ TiO2 TF (50 nm)/ Ag contact (150 nm) at 1 MHz
1/(C^2)
0.024
0.021
0.018
(c)
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10
Voltage(Volts)
Fig. 2. 1/C2 v/s V characteristics graphs at 1MHz frequency for a) n-Si/SiOx TF/Al contact (pMOS), b) n-Si/TiO2 TF/Ag contact (p-MOS), c) p-Si/TiO2 TF/Ag contact (n-MOS)
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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A Comparative Study on TiO2and SiOx Dielectric based MOS Capacitance
From 1/C2 v/s V characteristics, the obtained concentration of carriers is mentioned in the Table1.
Type
p-Si/TiO2 TF/Ag contact
(n-MOS)
n-Si/TiO2 TF/Ag contact
(p-MOS)
n-Si/SiOx TF/Al contact
(p-MOS)
Concentration[/
m3]
Vfb from graph Flatband Capacitance,
[volts]
Cfb [pF]
1.37×1019
8.5
6.26×1018
-2
1.56×1019
5.5
7.27
6.26
4.6
Table 1.Comparison of concentration, Vfb for a) p-Si/TiO2 TF/Ag contact (n-MOS), b) n-Si/TiO2
TF/Ag contact (p-MOS), c) n-Si/SiOx TF/Al contact (p-MOS)
4. CONCLUSION
The effect of introducing a high-k dielectric material (TiO2) with a Schottky contact w.r.t a low-k
dielectric material (SiOx) with an Ohmic contact has been studied. The presence of Schottky
contact reduces the tunneling and high-k dielectric is used to increase the value of capacitance thus
allowing shrinking of device with minimum leakage current and an increase in capacitance as
observed in C-V characteristics resulted in increased switching time.
5. ACKNOWLEDGEMENT
The authors are thankful to NIT Agartala for financial support.
REFERENCES
[1] Narendra S G, Chandrakasan A. Leakage in nanometer CMOS technologies, 2006 Newyork
[2] Alvarado U, Bistué G, Adin I.Low Power RF Circuit Design in Standard CMOS Technology, 2011;
Heidelberg: 307
[3] Jhaveri R, Nagavarapu V, Woo J C S. Effect of Pocket Doping and Annealing Schemes on the SourcePocket Tunnel Field-Effect Transistor IEEE Electron Device Lett. 2011; 58(1):80-86
[4] Roy K, Mukhopadhyay S, Mahmoodi M H. Leakage Current Mechanisms and Leakage Reduction
Techniques in Deep-Submicrometer CMOS Circuits IEEE Electron Device Lett. 2003; 91(2):305-327
[5] Husain M K, Li X V, Groot C H D. High-Quality Schottky Contacts for Limiting Leakage Currents in
Ge-Based Schottky Barrier MOSFETs IEEE Electron Device Lett. 2009; 56(3):499-504
[6] RichterC A, HefnerA R, VogelEM.A comparison of Quantum-Mechanical Capacitance-Voltage
Simulators, IEEE Electron Device Lett., 2001; 22 : 35-37.
[7] Matsuzawa K, Uchida K, Nishiyama A. Simulations of Schottky barrier diodes and tunnel transistors,
Computational Electronics, 1998; 163-165
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
29
Ashik Some, Diksha Barnwal, Arnab Shome, Birojit Chakma, Lalaram Arya, B.S.Thoma, Aniruddha Mondal
[8] Park Y, Ahn K S; Hyunsoo K. Carrier Transport Mechanism of Ni/Ag/Pt Contacts to p-Type GaN. IEEE
Electron Device Lett. 2012; 59(3):680-684
[9] Dhar J C, Mondal A, Singh N K,Chinnamuthu P.Low Leakage TiO2 Nanowire Dielectric MOS Device
Using Ag Schottky Gate Contact. IEEE T Nanotechnol. 2013; 12:948-950
[10] Walstra S V, Sah C T. Thin oxide thickness extrapolation from capacitance-voltage measurements. IEEE
Electron Device Lett. 1997; 44:1136-1142
[11] Srivastava V M. Capacitance-Voltage Measurement for Characterization of a Metal-Gate MOS Process.
Int J of Recent Trends in Engineering 2009;1(4):4-7
[12] Groner M D, George S M High-k dielectrics grown by atomic layer deposition: capacitor and gate
applications 2003; USA:327
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
30
Cost- Benefit Analysis of Two-Dissimilar Units
Warm Standby System Subject to Electromagnetic
Vibrations with Switch Failure
Ashok Kumar Saini
Banwari Lal Jindal Suiwala College, Tosham (Bhiwani) Haryana, INDIA
ABSTRACT
In this paper, we present a two-unit dissimilar warm standby systems subject to electromagnetic
vibrations(denoted as EM vibrations) with switch failure .The EM vibrations and failure rates
are constant whereas the repair time distributions are taken to be arbitrary. The EM vibrations
are non-instantaneous and cannot occur simultaneously in both the units and when there are
EM vibrations within specified limit of a unit, it operates as normal as before but if these are
beyond the specified limit the operation of the unit stop automatically so that excessive damage
of the unit is avoided and the EM vibrations goes on, some characteristics of the stopped unit
change which we call failure of the unit. We have calculated MTSF, Availability ,the expected
busy time of the server for repairing the failed unit under EM vibration in (0,t], the expected
busy time of the server for repair of dissimilar units by the repairman in(0,t], the expected busy
time of the server for repair of switch in (0,t], the expected number of visits by the repairman for
repairing the different units in (0,t], the expected number of visits by the repairman for repairing
the switch in (0,t] and cost analysis. Special case by taking repair time distribution as
exponential are discussed and graphs are drawn.
Keyword- dissimilar units, warm standby, switch failure, EM vibrations
1. INTRODUCTION
We present a two-unit dissimilar warm standby systems subject to EM vibrations with switch
failure .The EM vibrations and failure rates are constant where as the repair time distributions are
taken to be arbitrary. The EM vibrations are non-instantaneous and cannot occur simultaneously in
both the units and when there are EM vibrations within specified limit of a unit, it operates as
normal as before but if these are beyond the specified limit the operation of the unit stop
automatically so that excessive damage of the unit is avoided and when the EM vibrations goes on,
some characteristics of the stopped unit change which we call failure of the unit.
For example, when a satellite launched into its orbit around the earth there is a region of
electromagnetic field. When the satellite passes through such field some equipment present in the
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
31
Ashok Kumar Saini
satellite might be disturbed due to electromagnetic vibrations in the space which may deviate the
satellite from the orbit causing it directionless for a while. To control this situation it is possible
with the help of sensors that for some time the working of the equipment under the influence of
electromagnetic vibrations may stop and the sensors again detect where and when electromagnetic
field finished after which in the satellite, through the sensor control unit , the working of the
equipment under influence of electromagnetic vibrations starts immediately. It is assumed that all
the sensors system is perfectly working whenever needed.
2. ASSUMPTIONS
1.
The system consists of two dissimilar warm standby units. The EM vibration and failure
time of units and switch failure distributions are exponential with rates λ1, λ2, λ3 and λ4
respectively whereas the repairing rates for repairing the failed system due to EM
vibrations and due to switch failure are arbitrary with CDF G1 (t) & G2 (t) respectively.
2.
The operation of units stops automatically when EM vibrations occurs so that excessive
damage of the unit can be prevented.
3.
The EM vibrations actually failed the units. The EM vibrations are non-instantaneous and
it cannot occur simultaneously in both the units.
4.
The repair facility works on the come first serve (FCFS) basis.
5.
The switches are imperfect and instantaneous.
6.
All random variables are mutually independent.
Symbols for states of the System
Superscripts O, WS, SO, F, SFO
Operative , Warm Standby, Stops the operation , Failed, Switch failed but operable respectively
Subscripts nv, uv,ur, wr, uR
No EM vibration, under EM vibration, under repair, waiting for repair, under repair continued
respectively
Up states – 0,1,2,9 ; Down states – 3,4,5,6,7,8,10,11
States of the System
0(Onv , WSnv)
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Cost- Benefit Analysis of Two-Dissimilar Units Warm Standby System Subject to Electromagnetic
Vibrations with Switch Failure
One unit is operative and the other unit is warm standby and there are no EM vibrations in both the
units.
1(SOnv , Onv)
The operation of the first unit stops automatically due to EM vibrations and warm standby units
starts operating.
2(Fur , Onv)
The first unit fails and undergoes repair after the EM vibrations are over and the second unit
continues to be operative due to EM vibrations in it .
3(FuR , SOuv)
The repair of the first unit is continued from state 2 and in the second unit stops automatically due
to EM vibrations.
4(Fur , SOuv)
The first unit fails and undergoes repair after the vibrations are over and the other unit also stops
automatically due to EM vibrations.
5(FuR , Fwr)
The repair of the first unit is continued from state 4 and the other unit is failed due to EM
vibrations in it & is waiting for repair.
6(Onv , Fur)
The repair of the first unit is completed & it starts operation and the second unit which was waiting
for repair undergoes repair.
7(SOuv , SFOnv,ur)
The operation of the first unit stops automatically due to EM vibrations from state 0 and during
switchover to the second unit switch fails and undergoes repair.
8(Fwr , SFOnv,ur)
The repair of the switch is continued from state 7 and the first unit fails after EM vibrations and is
waiting for repair.
9(Onv , SOuv)
The first unit is operative and the warm standby dissimilar unit comes under the EM vibrations.
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
33
Ashok Kumar Saini
10(SOnv , Fur)
The operation of the first unit stops automatically due to EM vibrations and the second unit fails
and undergoes
ndergoes repair after the EM vibrations are over.
11(Fwr , FuR)
The repair of the second unit is continued from state 10 and the first unit is failed and waiting for
repair.
Emerging Energy Technology perspectives-A
A Sustainable Approach - ISBN: 978-93-83083-73-2
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Cost- Benefit Analysis of Two-Dissimilar Units Warm Standby System Subject to Electromagnetic
Vibrations with Switch Failure
Transition Probabilities
Simple probabilistic considerations yield the following expressions :
p01 = , P07 =
p09 =
, p12 =
, p14 =
P20= G1*( λ1) , P22(3) = G1*( λ1) , P72 = G2*( λ4) , P72(8) = G2*( λ4)= P78
Also other values can be defined.
We can easily verify that
P01 + P07 + P09 = 1, P20 + P22(3) = 1 , P22(3) = 1,
P60= 1 , P72+ P72(8) + P74 = 1 , P9,10= 1 , P10,2 + P10,2(11) = 1
(1)
And mean sojourn time are
)
µ 0 = E(T) = !* "#$ > &'(&
(2)
Mean Time To System Failure
We can regard the failed state as absorbing
+* ,&) = .* ,&)#/'+ ,&) + .*0 ,&)#/'+0 ,&) + .*1 ,&)
, )
+ ,&) = . ,&)#/'+ ,&) + . ,&) , + ,&) = .* ,&)#/'+* ,&) + . ,&)
+ ,&) = .0,* ,&)
(3-5)
Taking Laplace-Stiltjes transform of eq. (3-5) and solving for
.*∗ ,/) = N1(s) / D1(s)
(6)
Where
∗ ,/)
∗ ,/). , )∗ ,/)
∗ ,/)}
∗ ,/). ∗ ,/)
∗ ,/)
N1(s) = .*
{ .
+ .
+ .*0
+ .*1
0,*
∗ ,/)
∗ ,/). ∗ ,/)
.
D1(s) = 1 - .*
*
Making use of relations (1) & (2) it can be shown that .*∗ ,0) =1 , which implies
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
35
Ashok Kumar Saini
that + ,&) is a proper distribution.
6
∗ ,/)
MTSF = E[T] = 67 .*
= (D1’(0) - N1’(0)) / D1 (0)
s=0
= ( 8* +p01 8 + p01 p12 8 + p09 80 ) / (1 - p01 p12 p20 )
where
8* = 8* + 8*1 + 8*0 , 8 = 8 + 8 ,8 = 8* + 8 (3) , 80 = 80,*
Availability analysis
Let Mi(t) be the probability of the system having started from state I is up at time t without making
any other regenerative state belonging to E. By probabilistic arguments, we have
The value of M0(t), M1(t), M2(t), M4(t) can be found easily.
The point wise availability Ai(t) have the following recursive relations
A0(t) = M0(t) + q01(t)[c]A1(t) + q07(t)[c]A7(t) + q09(t)[c]A9(t)
A1(t) = M1(t) + q12(t)[c]A2(t) + q14(t)[c]A4(t) , A2(t) = M2(t) + q20(t)[c]A0(t) + q22(3)(t)[c]A2(t)
A4(t) = q46(3)(t)[c]A6(t) , A6(t) = q60(t)[c]A0(t)
A7(t) = (q72(t)+ q72(8)(t)) [c]A2(t) + q74 (t)[c]A4(t)
A9(t) = M9(t) + q9,10(t)[c]A10(t) , A10(t) = q10,2(t)[c]A2(t) + q10,2(11)(t)[c]A2(t) (7-14)
Taking Laplace Transform of eq. (7-14) and solving for 9:* ,/)
9:* ,/) = N2(s) / D2(s)
(15)
Where
> 0(s) + ;<01(s)=
> 1(s) + ;<09(s)=
> 9(s)}+=
> 2(s){ ;<01(s) ;<42(s) +
N2(s) = (1 - ;< 22(3)(s)) { =
(8)
(11)
;
? 07(s),;<72(s) + ;< 73 (s)) + ;< 09 (s);< 9,10 (s)(;< 10,2 (s) +;< 10,2 (s))}
D2(s) = (1 - ;< 22(3)(s)) { 1 - ;< 46(5)(s) ;<60(s)( ;<01(s);< 44 (s) +;<07(s) ;<74(s))
- ;
? 20(s){;<01(s);
? 12(s)+;<07(s)( ;< 72(s)) + ;< 72(8)(s) + ;< 09 (s);< 9,10 (s)
(;< 10,2 (s) +;< 10,2(11)(s))}
The steady state availability
A0 = limD→) #9* ,&)' = lim7→* #/9:* ,/)' = lim7→*
Using L’ Hospitals rule, we get
A0 = lim7→*
,7)7 G,7)
F G,7)
=
,*)
F G,*)
7 ,7)
F ,7)
(16)
Where
> 0(0) + p01=
> 1(0) + p09 =
> 9(0) ) + =
> 2(0) (p01p12 + p07 (p72
N2(0)= p20(=
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
36
Cost- Benefit Analysis of Two-Dissimilar Units Warm Standby System Subject to Electromagnetic
Vibrations with Switch Failure
+ p72(8) + p09 ))
D2’(0) = p20{ 8* + p018 + (p01 p14 + p07 p74 )8 + p07 81 + p07 81 + p09(80 + 8* )
+8 { 1- ((p01p14 + p07 p74 )}
8 = 8
,I)
H
, 81 = 81 + 8
,J)
+
1
8
1
, 8* = 8*, + 8
The expected up time of the system in (0,t] is
>
∝
Q ,S)
KL (t) = !* 9* ,N)(N So that KOL ,s) = R = the system in (0,t] is
S
,T)
TF ,T)
,)
*,
(17)
The expected down time of
K6 (t) = t- KL (t) So that KO6 ,s) = S − KOL ,s)
(18)
The expected busy period of the server for repairing the failed unit under EM vibration in
(0,t]
R0(t) = S0(t) + q01(t)[c]R1(t) + q07(t)[c]R7(t) + q09(t)[c]R9(t)
R1(t) = S1(t) + q12(t)[c]R2(t) + q14(t)[c]R4(t) , R2(t) = q20(t)[c]R0(t) + q22(3)(t)[c]R2(t)
R4(t) = q46(3)(t)[c]R6(t) , R6(t) = q60(t)[c]R0(t)
R7(t) = (q72(t)+ q72(8)(t)) [c]R2(t) + q74 (t)[c]R4(t)
R9(t) = S9(t) + q9,10(t)[c]R10(t) , R10(t) = q10,2(t) + q10,2(11)(t)[c]R2(t) (19-26)
O* ,/)
Taking Laplace Transform of eq. (19-26) and solving for V
O* ,/) = N3(s) / D2(s)
V
(27)
Where
N2(s) = (1 - ;< 22(3)(s)) { W: 0(s) + ;<01(s)W: 1(s) + ;<09(s)W: 9(s)} and D2(s) is already defined.
In the long run,
R0 =
X ,*)
F G,*)
where N3(0)= p20(W:0(0) + p01W:1(0) + p09 W:9(0) ) and D2’(0) is already defined.
The expected period of the system under EM vibration in (0,t] is
(28)
>
∝
[R ,S)
KYZ (t) = !* V* ,N)(N So that KO
YZ ,s) = S
The expected Busy period of the server for repair of dissimilar units by the repairman in (0,t]
B0(t) = q01(t)[c]B1(t) + q07(t)[c]B7(t) + q09(t)[c]B9(t)
B1(t) = q12(t)[c]B2(t) + q14(t)[c]B4(t) , B2(t) = q20(t)[c] B0(t) + q22(3)(t)[c]B2(t)
B4(t) = T4 (t)+ q46(3)(t)[c]B6(t) , B6(t) = T6 (t)+ q60(t)[c]B0(t)
B7(t) = (q72(t)+ q72(8)(t)) [c]B2(t) + q74 (t)[c]B4(t)
B9(t) = q9,10(t)[c]B10(t) , B10(t) = T10 (t)+ (q10,2(t) + q10,2(11)(t)[c]B2(t) (29-36)
Taking
O* ,/)
Laplace Transform of eq. (29-36) and solving for\
O* ,/) = N4(s) / D2(s)
\
(37)
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Ashok Kumar Saini
Where
> 4(s) + ;<46 (5)(s)$] 6(s)) +;< 07(3)(s) ;
> 4(s)
N4(s) = (1 - ;< 22(3)(s)) { ;<01(s);<14(s),$
? 74(s)($
(5)
> 10(s) )
? 09,10(s) $
+;< 46 (s)$] 6(s))+ ;<09(s);
And D2(s) is already defined.
In steady state, B0 =
^ ,*)
F G,*)
(38)
where N4(0)= p20 {( p01 p14 + p07 p74) ($]4(0) +$]6(0)) + p09 $]10(0) } and D2’(0) is already defined.
The expected busy period of the server for repair in (0,t] is
>
∝
_R ,S)
KYL (t) = !* \* ,N)(N So that KO
YL ,s) = S
The expected Busy period of the server for repair of switch in (o,t]
P0(t) = q01(t)[c]P1(t) + q07(t)[c]P7(t) + q09(t)[c]P9(t)
P1(t) = q12(t)[c]P2(t) + q14(t)[c]P4(t) , P2(t) = q20(t)[c]P0(t) + q22(3)(t)[c]P2(t)
P4(t) = q46(3)(t)[c]P6(t) , P6(t) = q60(t)[c]P0(t)
P7(t) = L7(t)+ (q72(t)+ q72(8)(t)) [c]P2(t) + q74 (t)[c]P4(t)
P9(t) = q9,10(t)[c]P10(t) , P10(t) = (q10,2(t) + q10,2(11)(t))[c]P2(t) (40-47)
Taking Laplace Transform of eq. (40-47) and solving for
O* ,/) = N5(s) / D2(s)
"
where N2(s) = ;
? 07(s ) `] 7(s) ,1 - ;< 22(3)(s)) and D2(s) is defined earlier.
In the long run , P0 =
a ,*)
F G,*)
where N5(0)= p20 p07 `]4(0) and D2’(0) is already defined.
The expected busy period of the server for repair of the switch in (0,t] is
>
∝
bR ,S)
KY7 (t) = !* "* ,N)(N So that KO
Y7 ,s) = S (39)
(48)
(49 )
(50)
The expected number of visits by the repairman for repairing the different units in (0,t]
H0(t) = Q01(t)[c]H1(t) + Q07(t)[c]H7(t) + Q09(t)[c]H9(t)
H1(t) = Q12(t)[c][1+H2(t)] + Q14(t)[c][1+H4(t)] , H2(t) = Q20(t)[c]H0(t) + Q22(3)(t)[c]H2(t)
H4(t) = Q46(3)(t)[c]H6(t) , H6(t) = Q60(t)[c]H0(t)
H7(t) = (Q72(t)+ Q72(8)(t)) [c]H2(t) + Q74 (t)[c]H4(t)
H9(t) = Q9,10(t)[c][1+H10(t)] , H10(t) = (Q10,2(t)[c] + Q10,2(11)(t))[c]H2(t) (51-58)
Taking Laplace Transform of eq. (51-58) and solving for c*∗ ,/)
c*∗ ,/) = N6(s) / D3(s)
(59)
Where
N6(s) = (1 – . 22(3)*(s)) { .∗ 01(s),. ∗ 12(s)+. ∗14(s)) +. ∗ 09 (s). ∗ 9,10 (s)}
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Cost- Benefit Analysis of Two-Dissimilar Units Warm Standby System Subject to Electromagnetic
Vibrations with Switch Failure
D3(s) = (1 - . 22(3)*(s)) { 1 - (.∗ 01(s). ∗ 14 (s) +. ∗07(s) .∗ 74(s)).46(5)*(s) .∗ 60(s)}
- .∗ 20(s){. ∗01(s). ∗ 12(s)+. ∗07(s)( .∗ 72(s)) + .∗ 72(8)(s) +
.∗ 09 (s). ∗ 9,10 (s) (. ∗ 10,2 (s) +Q 10,2(11)*(s))}
In the long run , H0 =
d ,*)
FX G,*)
(60 )
where N6(0)= p20 (p01 + p09) and D’3(0) is already defined.
The expected number of visits by the repairman for repairing the switch in (0,t]
V0(t) = Q01(t)[c]V1(t) + Q07(t)[c]V7(t) + Q09(t)[c]V9(t)
V1(t) = Q12(t)[c]V2(t) + Q14(t)[c]V4(t) , V2(t) = Q20(t)[c]V0(t) + Q22(3)(t)[c]V2(t)
V4(t) = Q46(3)(t)[c]V6(t) , V6(t) = Q60(t)[c]V0(t)
V7(t) = (Q72(t)[1+V2(t)]+ Q72(8)(t)) [c]V2(t) + Q74 (t)[c]V4(t)
V9(t) = Q9,10(t)[c]V10(t) , V10(t) = (Q10,2(t) + Q10,2(11)(t))[c]V2(t)
(61-68)
Taking Laplace-Stieltjes transform of eq. (61-68) and solving for e* ∗ ,/)
e* ∗ ,/) = N7(s) / D4(s)
(69)
(3)*
∗
∗
where N7(s) = . 07 (s). 72 (s) (1 – . 22 (s)) and D4(s) is the same as D3(s)
In the long run , V0 =
f ,*)
F^ G,*)
(70)
where N7(0)= p20 p07 p72 and D’3(0) is already defined.
Cost Benefit Analysis
The cost-benefit function of the system considering mean up-time, expected busy period of the
system under vibrations when the units stops automatically, expected busy period of the server for
repair of unit & switch, expected number of visits by the repairman for unit failure, expected
number of visits by the repairman for switch failure.
The expected total cost-benefit incurred in (0,t] is
C(t) = Expected total revenue in (0,t] - expected total repair cost for switch in (0,t]
- expected total repair cost for repairing the units in (0,t ]
- expected busy period of the system under vibration when the units automatically stop in (0,t]
- expected number of visits by the repairman for repairing the switch in (0,t]
- expected number of visits by the repairman for repairing of the units in (0,t]
The expected total cost per unit time in steady state is
C =limD→) ,g,&)/&) = lim7→* ,/ g,/))
= K1A0 - K2P0 - K3B0 - K4R0 - K5V0 - K6H0
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Ashok Kumar Saini
Where
K1 - revenue per unit up-time,
K2 - cost per unit time for which the system is under switch repair
K3 - cost per unit time for which the system is under unit repair
K4 - cost per unit time for which the system is under EM vibrations when units automatically stop.
K5 - cost per visit by the repairman for which switch repair,
K6 - cost per visit by the repairman for units repair.
3. CONCLUSION
After studying the system, we have analysed graphically that when the failure rate, EM vibration
rate increases, the MTSF and steady state availability decreases and the cost function decreased as
the failure increases.
REFERENCES
[1] Barlow, R.E. and Proschan, F., Mathematical theory of Reliability, 1965; John Wiley, New York.
[2] Dhillon, B.S. and Natesen, J, Stochastic Anaysis of outdoor Power Systems in fluctuating environment,
Microelectron. Reliab. .1983; 23, 867-881.
[3] Gnedanke, B.V., Belyayar, Yu.K. and Soloyer , A.D. , Mathematical Methods of Relability Theory,
1969 ; Academic Press, New York.
[4] Goel, L.R., Sharma, G.C. and Gupta, Rakesh Cost Analysis of a Two-Unit standby system with different
weather conditions, Microelectron. Reliab, 1985; 25, 665-659.
[5] Goel,L.R. ,Sharma G.C. and Gupta Parveen , Stochastic Behaviour and Profit Anaysis of a redundant
system with slow switching device, Microelectron Reliab., 1986; 26, 215-219.
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Study on Power System Planning in India
Dharmesh Rai1, Vinod Kumar Yadav2, Syed Rafiullah3, Adesh Kumar Mishra4
1
Student, Department of EEE, Galgotias University, U.P, India.
2
Department of EEE, Galgotias University, U.P, India.
3
Student, Department of EEE, Galgotias University, U.P, India.
4
Student, Department of EEE, Galgotias University, U.P, India.
ABSTRACT
This paper discuss the important aspects and issues related with power system planning in India.
To Enhance the facilities of power system, one must to assess load forecasting. Future load
growth in the face of uncertainties associated with future load forecasting, the type and
availability of fuel for generating units, the complexity of interconnection between different
agents and opportunities to exploit new technologies. In which manner we get suitable reliability
that can assurance a continuous power flow with reasonable and acceptable cost. The proposed
work will try to show the most tiring and main problems and issues that face electric power
system in India and effects the decision making process.
Keywords: Planning, Reliability, Cost, Load, Interconnection
1. INTRODUCTION
Power system planning is a process in which the aim is to decide on new as well as upgrading
existing system element to adequately satisfy the loads for a foreseen future. In India, power
system planning has become more difficult, but more important to provide the necessary
information to enable decision to be made today about many years in the future.
In this paper, we will consider power system planning where it is necessary to treat the system as a
whole and choose the part in the system so that they give the required technical performance and
are also economically justified. Under such a situation, the effort will be to make the system
economical and not only one particular part of the system such as generation, transmission or
distribution.
This framework should be flexible, not rigid with broad objectives of finding a plan which
guarantees a desired degree of a continuous, reliable and least cost service. Good service or, in
other words, acceptable reliability level of power system usually requires additions of more
generating capacity to meet the expected increase in future electrical demands.
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Dharmesh Rai, Vinod Kumar Yadav, Syed Rafiullah, Adesh Kumar Mishra
However, In India with vast, separately populated areas reliability–cost tradeoffs exist between
satisfying the fast load growth by investment in additional generating capacity for isolated systems
or building transmission networks to interconnect these systems and transfer power between their
load centers in case of emergencies and power shortages. Therefore, reliability and cost constraints
are major considerations in power system planning process.
2. GENERATION PLANNING
When the planning requirements have been determined, the next problem is to determine the type
and size of generation station that will be required to supply power and energy. The selection of a
site for the location of the generating stations depends on many factors including the cost of
transmitting the energy to the consumers, of transporting fuel to the stations, the viability of sound
foundations, the cost of land, the availability of cooling after and the avoidance of atmospheric
pollution. Steam station should be located at the coal pits or as near the coal as possible to avoid
transport cost and time of transport. For most economical distribution and the lowest cost of power
and energy, the power station should be located at the center of gravity of load, if a suitable site is
available. There is a trend for in the size of generator unit to be used in large power systems. This
reduces the cost per kw and improves the efficiency of the station.
Careful choice should be made of the composition and characteristics of the generation plant and it
should be possible to continue studies every time a new event occurs such as energy crisis which
may affect the conclusions reached. The choice of sitting new thermal and unclear plants is studies
as optimization problem using linear programing. The points considered are costs of production,
transport and interaction with the environment to the minimum.
3. TRANSMISSION SYSTEM PLANNING
The major transmission requirements of a power system and their associated cost are much
influenced by the location of future generation capacity. The object of transmission planning is to
select the most desirable transmission network for each of the generation expansion patterns under
consideration. Both economics and reliability are considered in the problem. The application of a
digital computer in automated transmission planning allows the system planner to consider and
investigate many alternatives quickly. The ultimate selection of generation expansion plan is ten
done by considering transmission planning allows the system planner to consider and investigate
many alternatives quickly. The ultimate selection of generation expansion plan is then done by
considering transmission as an integral part of the total cost.
A basic problem in transmission line planning is the determination of transmission adequacy under
the forced outage of various systems components. A more consistent approach to transmission
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Study on Power System Planning in India
planning would be to consider the reliability. The investment in transmission improvement is made
t the desired location in the system, in terms of an acceptable risk level at the loading point.
The transmission system planned to satisfy the bus voltage and line loadings under normal
operating condition may be adequate only if high risk level are acceptable. The cost of transmission
improvements
Increase as higher reliability levels are expected. The use of quantitative reliability criterion
facilities optimum utilization of the investments in transmission improvements.
4. DISTRIBUTION SYSTEM PLANNING
Since the system variable are quite complex, it is necessary to make a through analysis while
planning distribution system. The problem to be studied in the total system environment for the
purpose are (a) Selection of most economical combination of subtransmission and distribution
voltage levels, (b) Determination of the economical sizes of substations, and (c) Combination of
different methods of regulating voltage. Some of the important factors that should be considered
are the actual geographical distribution of lads, configuration of the existing system, step by step
expansion of the distribution system with time, and load growth and comparative reliability of the
various arrangement.
5. RELIABILITY EVALUATION
The degree of performance of the elements of the bulk electric system that results in electricity
being delivered to customers within accepted standards and in the amount desired. Reliability may
be measured by the frequency, duration, and magnitude of adverse effects on the electric supply
Reliability is one of the most important criteria which must be taken into consideration during all
phases of power system planning, design and operation. Reliability is Ability of a system to
perform its intended function. (a)Within a specified time period, (b) Under stated condition.
Reliability criterion is required to establish target reliability levels and to consistently analyze and
compare the future reliability levels with feasible alternative expansion plans. One capacity related
reliability index, known as the loss of load expectation (LOLE) method. This method computes the
expected number of days per year on which the available generating capacity is not sufficient to
meet all the period load levels and can be evaluated as:
(1)
where p(Ok) is the probability of loss of load due to the kt severe outage of size Ok; tk is the time
duration of that severe outage Ok will take; n is the total number of severe outages occurred during
that period considered. Any outage of generating capacity exceeding the reserve will result in a
curtailment of system power. Therefore, another power related reliability index, known as the
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Dharmesh Rai, Vinod Kumar Yadav, Syed Rafiullah, Adesh Kumar Mishra
expected power not served (ENS), is also used to complement the LOLE index, and can be defined
as:
(2)
Where (ENS)k is the energy not served
ed due to severe kth outage of size Ok.
6. RELIABILITY EVALUATION
In power system cost-benefit
benefit analysis, the outages cost (OC) forms a major part in the total system
cost. These costs are associated with the power demanded but cannot be served by the system due
d
to severe outages and is known as the expected power not served (e(ENS)). Outages cost will be
borne by the utility and its customers. The utility outages cost includes loss of revenue, loss of
goodwill, loss of future sales and increased maintenance and
an repair expenditure. However, the
utility losses are small compared to the losses incurred by the customers when power interruptions
occur. A residential consumer may suffer a great deal of anxiety and inconvenience if an outage
occurs during a hot summer day or deprives him from domestic activities and causes food spoilage.
For a commercial user, he will also suffer a great hardship and loss of being forced to close until
power is restored. Also, an outage may cause a great damage to an industrial customer
custome if it occurs
and disrupts the production process. Therefore, for estimating the outages cost, OC, is to multiply
the value of e(ENS) by an appropriate outage cost rate (OCR), as follows:
(3)
The total cost of supplying the electric power to the consumers is the sum of system cost that will
generally increase as consumers are provided with higher reliability and customer outages cost that
will, however, decrease as the reliability increases. This total system cost (TSC) can be expressed
in the following equation:
(4)
The prominent aspect of outage cost estimation, as noticed in the above equation, is to assess the
worth of power system reliability and to compare it with the cost of system reinforcement in order
to establish the appropriatee system reliability level that ensures both power continuity and the least
cost of its production.
7. ISOLATED AND INTERCONNECTED
NNECTED POWER SYSTEMS
SYSTEM
Interconnection of electrical power systems is an effective means of not only enhancing the overall
system reliability
lity but also reducing its operating reserve. The diversity existing between different
systems in regard to their load requirements and capacity outages will allow the systems to assist
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Study on Power System Planning in India
each other in times of emergencies and generation deficiencies. The aim
ai of this study is to specify
the reliability levels for each system individually as a result of future load growth over the next
eight years and the expected deterioration of reliability levels as a result of diminishing reserve and
capacity deficit. Afterr specifying the year that reliability level has exceeded the prescribed
reliability level, capacity addition (new generating units) can be decided upon or interconnection
with another system can be an optional solution. The interconnection reduces the amount
amo
of
generating capacity required to be installed as compared with that which would be required without
the interconnection. The amount of such reduction depends on the amount of assistance that a
system can get, the transfer capability of the tie-line
line and
a the availability of excess capacity reserve
in the assisting systems. Therefore, the study is focused on reliability evaluation of two systems
both as isolated systems and as interconnected systems. Analysis of this type explores the benefits
that may accrue
ccrue from interconnecting systems rather being isolated as well as deciding viable
generation expansion plans. The analysis represents the expansion plans for two systems as being
isolated and interconnected. Higher reliability levels and lower installation
installati and operation costs after
the proposed interconnection between these selected isolated power systems take place.
8. OUTAGES COST EVALUATION
In power system cost-benefit
benefit analysis, the outages cost (OC) forms a major part in the total system
cost. These costs
ts are associated with the power demanded but cannot be served by the system due
to severe outages and is known as the expected power not served (e(ENS)). Outages cost will be
borne by the utility and its customers. The utility outages cost includes loss of
o revenue, loss of
goodwill, loss of future sales and increased maintenance and repair expenditure. However, the
utility losses are small compared to the losses incurred by the customers when power interruptions
occur. A residential consumer may suffer a great
reat deal of anxiety and inconvenience if an outage
occurs during a hot summer day or deprives him from domestic activities and causes food spoilage.
For a commercial user, he will also suffer a great hardship and loss of being forced to close until
power is restored. Also, an outage may cause a great damage to an industrial customer if it occurs
and disrupts the production process. Therefore, for estimating the outages cost, OC, is to multiply
the value of e(ENS) by an appropriate outage cost rate (OCR), as
a follows:
(3)
The total cost of supplying the electric power to the consumers is the sum of system cost that will
generally increase as consumers are provided with higher reliability and customer outages cost that
will,
ll, however, decrease as the reliability increases. This total system cost (TSC) can be expressed
in the following equation:
Emerging Energy Technology perspectives-A
A Sustainable Approach - ISBN: 978-93-83083-73-2
45
Dharmesh Rai, Vinod Kumar Yadav, Syed Rafiullah, Adesh Kumar Mishra
(4)
The prominent aspect of outage cost estimation, as noticed in the above equation, is to assess the
worth of power system reliability and to compare it with the cost of system reinforcement in order
to establish the appropriate system reliability level that ensures both power continuity and the least
cost of its production.
9. LOAD FORECASTING AND ENERGY
ERGY REQUIREMENT
Power system planning starts with a forecast of anticipated future load requirements. The term
forecast refers to projected load requirements determined using a systematic process of defining
future loads in sufficient quantitative detail to permit important system expansion decisions to be
made. When planning to utilize the natural energy resources in India, it must be kept in mind that
implementation takes time and needs a lot of capital investment. Decision must be taken
ta
in advance
for judicious and profitable investment in various project to make them effective useful and
economical. Forecast of demand for energy are required to estimate the additional installed
capacity required to facilitate the plant maintenance programme
pr
and to estimate the plant capacity
of restricted hydro plants.
10. ISOLATED AND INTERCONNECTED
NNECTED POWER SYSTEMS
SYSTEM
Interconnection of electrical power systems is an effective means of not only enhancing the overall
system reliability but also reducing its operating
erating reserve. The diversity existing between different
systems in regard to their load requirements and capacity outages will allow the systems to assist
each other in times of emergencies and generation deficiencies. The aim of this study is to specify
the reliability levels for each system individually as a result of future load growth over the next
eight years and the expected deterioration of reliability levels as a result of diminishing reserve and
capacity deficit. After specifying the year that reliability
re
level has exceeded the prescribed
reliability level, capacity addition (new generating units) can be decided upon or interconnection
with another system can be an optional solution. The interconnection reduces the amount of
generating capacity required
quired to be installed as compared with that which would be required without
the interconnection. The amount of such reduction depends on the amount of assistance that a
system can get, the transfer capability of the tie-line
line and the availability of excess capacity reserve
in the assisting systems. Therefore, the study is focused on reliability evaluation of two systems
both as isolated systems and as interconnected systems. Analysis of this type explores the benefits
that may accrue from interconnecting systems
stems rather being isolated as well as deciding viable
generation expansion plans. The analysis represents the expansion plans for two systems as being
isolated and interconnected. Higher reliability levels and lower installation and operation costs after
the proposed interconnection between these selected isolated power systems take place.
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Study on Power System Planning in India
There are a number of upcoming issues that will affect the way electric system planning is done in
New England. These issues include:
11. EMERGING ISSUES
• Integration of wind and other intermittent resources
• Growth in renewable resources driven by the states, renewable portfolio standards and
potential federal actions that would promote use of renewables
• Accounting for the more aggressive energy efficiency growth policies
• Diversifying fuel resources
• Stricter environmental regulations
• Changes in regional and interregional cost allocation for new resources
• Additional merchant transmission projects
• Growth of smart grid technologies, and
• Governmental energy planning policies.
12. CONCLUSION
To successfully accelerate the development of Power system planning needs to be Lean and
optimal. The results show the benefits and issue associated with both reliability and cost of
interconnecting isolated systems into an integrated system. Therefore, their effects should be
anticipated and detract their effects so that possible deterioration in system reliability levels as well
as unnecessary additional expenditure can be avoid.
REFERENCES
[1] Billinton, R., Allan, R.N., 1988. Reliability Assessment of Large Electric Power Systems. Kluwer
Academic Publishers, Boston.
[2] Sullivan, R., 1977. Power System Planning. McGraw Hill, pp. 97–150
[3] Wang, E.J., 2008. Outage costs and strategy analysis for hi-tech industries. International Journal of
Quality and Reliability Management 19 (8–9), 1068–1078.
[4] M.-S. Chen, “Security Issues of Power System Interconnection,” IEEE Power Engineering Society,
General Meeting, 12-16 June 2005, Vol. 2, pp. 1797-1800.
[5] Munasinghe, M., 1979. The Economics of Power System Reliability and Planning. The World Bank
Publications, pp. 45–85.
[6] Choi, J., Watada, J., 2007. Transmission system expansion planning considering outage cost. In: Second
International Conference on Innovative Computing, Information and Control (ICICIC 2007), Kumamoto
City International Center, Kumamoto, Japan, September5–7, 2007.
[7] Government of India Ministry of Power Central Electricity Authority (February 2012), Draft on National
Electricity Plan
[8] London Economics 1990. Long Term Issues in Indian Power Sector. Report prepared for World Bank.
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Effect of Reforms in Distribution Sector
in Indian Power Scenario
J Sai Keshava Srinivas
University of Petroleum and Energy Studies,
Bidholi Campus, Via Prem Nagar, Misraspatti, Uttarakhand 248007, India
Keywords: Power, Reforms, Distribution, Electricity Act, DISCOMS
ABSTRACT
India, one of the largest Power producer in the world with an installed capacity of 237 GW is
facing a lot of issues in the Transmission and Distribution sectors. If we look across the
distribution scenario of the country, about 95% of the power is distributed through state owned
Electricity Boards (SEB’s). With the reforms of privatization in 1991, the entry to private
partners in the sector is encouraged. Even though the Electricity Act 2003 gave a provision to
the competition in the market, the sector lacks the competition due to the poor performance of
DISCOMS in the form of high ATC losses and thereby they are in huge debts. In order to
energise the health position of the DISCOMS, govt has come up with the reforms “Debt
Restructuring “and “Separation of distribution and retail supply business”.
Due to these reforms the distribution utilities in the country will have a greater relief but they
need to find out paths for the enhancement of the revenue generation in their area by adopting
latest technologies of smart metering so that same situation won’t arise again. The objective of
this paper is to analyse the financial situation of many DISCOMS in the country and the effect
of the above reforms on their financial health in the upcoming years and their expected growth
and suggest a solution that the utilities can adopt from the reforms from the Govt of India.
1. INTRODUCTION
Power is a basic infrastructure and backbone for the country’s economic growth and the per capita
consumption of electricity in any country justifies it. India being the 5th largest producers of
electricity in the world is unable to generate revenues that support and boost the generation sector
to get the investments. We have many acts ad policies supporting to the sector especially “The
Electricity Act 2003” which is crucial in promoting the competition in the sector. After
liberalization in the 1991 many private players have contributed to the industry but the growth is
being low due to many reasons and the primary reason being the problems in the Distribution
system.
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Effect of Reforms in Distribution Sector in Indian Power Scenario
This paper deals with the need for the distribution reforms and also the effects of the same on the
power sector in the nearby future.
2. INDIAN POWER SCENARIO
India having a generation capacity of 2,37,742.94 MW and a transmission capacity of 1,05,343 ckt
kms as on February 2014.The Power and demand deficit recently was only 3.3% which is the
lowest recorded in this financial year. Even though the situation seems quite satisfactory as the
Demand Supply mismatch being low to just 3% rather than 8-9% last year, the generating
companies are unable to get their return on Investment back due to the lack of revenue collection
from the state DISCOMS who are the primary procurers of the electricity.
As per recent reports the per capita consumption of electricity in India reached 917.18 KWh and
the coal consumption is 454.5 Million Tons per annum which are still to be improved in the due
course of time for the overall development of the country. The average debts of the distribution
companies in the present scenario is around 2,46,000 crore.
3. NEED FOR REFORMS
In the Indian context the revenue from the distribution is badly effected due to the high ATC
(Aggregate Technical and Commercial Losses) which constitute around about 25-27 % at National
Level. The Transmission and Distribution losses (Technical losses) are the losses which occur due
to the line losses in the power transfer have come down to around 20-22% in the country. There is
a huge need to reduce these losses as the numbers are quite high. The commercial losses include
the theft of electricity and non-metered electrical connections in any areas in the country. Because
of these high losses in the country the Distribution companies are unable to generate the revenue
for the actual energy they supplied. The other reason which influenced the revenue generation of
the Distribution companies is the tariff that is being set by the Regulatory commissions which is
quite low when compared with the generating cost.
Year
Unit Cost
Average Tariff
Gap between Cost and
Tariff
Gap as % Unit
Cost
2007-08
4.04
3.06
0.98
24%
2008-09
4.6
3.26
1.34
29%
2009-10
4.76
3.33
1.43
30%
2010-11
4.84
3.57
1.27
26%
2011-12
4.87
3.8
1.07
22%
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J Sai Keshava Srinivas
Source: “Annual Report 2011-12 on the Working of State Power Utilities and Electricity
Departments”, Planning Commission
The above table represents the costs of generation and the actual cost realized from the consumers
along with the % gap between both.
Govt of India have come up with many reforms in the country to counteract the situations by
introducing the following schemes:
•
APDRP (Accelerated Power Development and Reform Program ) Feb 2001
•
RAPDRP (Restructured Accelerated Power Development and Reform Program) July 2008
•
Debt Restructuring Plan for the Distribution Utilities Dec 2013
•
Separation of Supply and Wire business – Proposal
The above schemes in the distribution sector will help the utilities in improving their health
position and thereby improving their overall performance on a long run.
4. REFORMS ON THE INDIAN POWER SECTOR
The two recent themes are the hot topics at the moment for the distribution utilities which are
described hereunder:
5. DEBT RESTRUCTURING PLAN
Under this scheme the state DISCOMS are given an opportunity to improve their financial health
as they are involved in the accumulated debts of around 2.4 lakh crore. The Plan also threw light on
the increase in the tariff rates by decreasing the gap between the actual generation cost of power
and the revenue realized per unit. With rising fuel charges and stagnant rates, the gap rose to Rs
1.45 a unit (kilowatt per hour) in 2009-10 from 76 paisa in 1998-99.
This plan is structured in such a way that 50% of the short term liabilities are taken up by State
government. This shall be first converted into bonds to be issued by Discoms to participating
lenders, backed by a state government guarantee. State governments will take over the liability
during the next two to five years by issuing special securities in favour of participating lenders in a
phased manner; keeping in view the fiscal space available till the entire loan (50% of STL) is taken
over by state governments. The balance 50% of STL will be rescheduled by lenders and serviced
by Discoms with a principal moratorium of three years. Repayment of principal and interest would
be fully secured by a state government guarantee.
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Effect of Reforms in Distribution Sector in Indian Power Scenario
The following table represents the allocation of funds to six states under this scheme by the
government:
Phasing plan for state government securities for 50% STls of Discoms
(INR Crore)
State
Andhra Pradesh
50% of STLs
3,151
FY’13
2,211
FY’14
940
FY’15
FY’16
FY’17
Haryana
7,859
2,518
2,469
2,845
Madhya Pradesh
Punjab
585
5,823
72
881
513
1,004
1,145
1,305
1,488
Rajasthan
19,855
2,649
3,496
3,986
4,544
5,180
Tamil Nadu
Uttar Pradesh
9,573
12,967
884
1,919
2,526
2,245
2,880
2,559
3,283
2,918
3,326
Total
59,813
11,134
13,220
12,415
12,050
9,994
Out of these proposals by the GOI four states Jharkhand, Bihar and Andhra Pradesh and Tamilnadu
were offered with this package for restructuring.
6. EFFECTS OF THE REFORM
• The utility will get a temporary relief of the huge debts and will improve the financial health of
the DISCOMS.
• It will help in reducing the DISCOMS overall losses in the form of interests to be paid
• It would help them to make more PPA’s with the generation companies and thereby improve
the supply profile to the customer resulting in increase in their revenues.
• Overall with this govt initiative will help DISCOME to get back their previous state of
financial status and can supply electricity to consumers with increased reliability
7. SEPARATION OF WIRE AND SUPPLY BUSINESS:
This is a new proposal that recently came into picture from GOI for the distribution companies to
improve the competition among them and invite private participation. In this context, multiple
licensees are issued for distribution of electricity in an area and thereby increasing the competition
which leads to the reduction in the tariff of the electricity to the end consumers. In order to
implement this several amendments are to be made to the electricity act 2003, and National Tariff
Policy
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In this concept the Wire i.e. the distribution line will be maintained by one entity basically the state
electricity board in the respective states and the licensees are issued to use carry the content
through the carriage so that the licensees will pay substantial charges to the SEB.
8. EFFECTS OF THE REFORM
• With the introduction of the multiple licensees in a particular area there will be heavy
competition among the suppliers of the electricity there by the tariff of electricity decreases.
• The customers can chose the supply of their choice depending upon the reliability of the
supplier
• The state DISCOMS can receive income from the suppliers in the form of charges for the
usage of their supply lines
• The losses can be reduced as the licensees will try to maintain low losses to earn profits from
their end and there by the target of reduction of ATC losses is achieved
So in view of these two reforms let’s hope the Distribution Utilities in India will have a bright
future ahead and the Power sector is going to cherish in future with endeavours.
REFERENCES
[1] Information on http://www.cea.nic.in/
[2] Information on http://powermin.nic.in/
[3] Information on http://www.apdrp.gov.in/
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Biogas- An Alternative Source of Energy
Mohd Junaid Khalil1, Kartik Sharma2, Rimzhim Gupta3
Department of Chemical Engineering, Aligarh Muslim University, Aligarh-202002, INDIA
ABSTRACT
The objective of this paper is to analyse the production processes of biogas as an alternative
energy source. Biogas is generated from biomass by digestion under anaerobic conditions in the
presence of microorganisms in three stages involved in the combined anaerobic digestion
process. The biogas produced in anaerobic digestors could contain methane concentrations upto
80% by volume. This system can be integrated with the agricultural waste to produce biogas and
small play an important role in improving residential sanitation and economical development in
rural areas.
Keywords: biogas, biomass, anaerobic digestion, reaction parameters, renewable energy.
1. INTRODUCTION
Energy is the basis of human life. There is hardly any activity or moment that is independent of
energy. Every moment of the day we are using energy. Earlier man used muscle power, then fire
and animal power. Next, he learned to harness energy, convert it to useful form and put it to
various uses.
Energy sources are two types: they are conventional energy sources like coal, petroleum, natural
gas etc. & non-conventional energy sources like solar cells, fuel cells, thermo-electric generator,
thermionic converter, solar power generation, wind power generation, geo-thermal energy
generation, tidal power generation etc. Most of the energy consumption is from power generation,
transportation, industry, and community sectors. Moreover, the most utility energy, are taken from
fossil oil, gas and coal. Biogas, a clean and renewable form of energy, could very well be a
substitute for conventional energy sources, such as fossil fuels (coal, crude oil, natural gas). The
alternative-energy segment of the energy industry covers a broad range of sources. These sources
range from well-established technologies, such as nuclear energy and hydroelectric power, through
high-growth segments such as wind and solar power. They also include less tried and tested
alternatives, such as hydrogen-powered, fuel-cell technology for use in both electricity generation
and as an alternative to gasoline in the automotive industry.
The development of biogas energy, which is considered as an important energy resources for
future, is a fitting option to solve global environmental and energy issues in a sustainable manner.
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Mohd Junaid Khalil, Kartik Sharma, Rimzhim Gupta
It is needed on daily basis for various activities which cover both industrial and domestic
requirements. The domestic energy requirements cater for activities such as cooking, heating,
lighting and other similar domestic chores. Biomass will play a major role in the substitution of
fossil fuels with renewable resources. Renewable resources such as solar, wind, hydropower, and
biogas are potential candidates to meet global energy requirements in a sustainable way. Biogas is
naturally produced when any organic matter including landfill sites, weeds, woods, grasses, leaves,
fruits and vegetable solids wastes, wastewater treatments facilities, animal farm manure, algae,
compost, sewage and agro-food sludge decomposes under anaerobic conditions. Biogas is
comprised primarily of methane (50-70%) and carbon dioxide (25-45%) in approximately 3:2
ratio. Methane is the important component, as it is a highly flammable gas that can be utilized as
fuel for cooking, lighting, water heaters and, if the sulphur is removed, it can be used to run biogasfuelled generators to produce electricity. One main advantage of biogas is the waste reduction
potential. Biogas production by anaerobic digestion is popular for treating biodegradable waste
because valuable fuel can be produced while destroying disease causing pathogens and reducing
the volume of disposed waste products. The objective of the present article is to review and
summarize the progresses made and recent trends in biogas technologies, including anaerobic
digestion processes.
2. ENERGY CRISIS IN VIEW OF GROWING DEMAND
Many households in world are facing the problem of an inadequate energy supply. The availability
of traditional cooking fuel such as fuel wood, agricultural residues , dried dung and charcoal is also
declining, while commercial fuel are often, too expensive. Even, if the demand for energy remains
at its current level of the majority of fossil fuels will be exhausted in 21 century. Only the supply of
the coal is provided for more than 200 years. In long term, it is clean that price of supplies of the
fossil fuel will increase steadily. They will have great impact on developing countries that import
energy. In this context, renewable energy source contribute to more secure energy supply. The
renewable energy sources are better solution then fossil fuels.
3. DEPLETION OF NON-RENEWABLE RESOURCES
The extensive depletion of non-renewable resources, particularly oil, along with a higher level of
consumption will have a significant impact on the economic development of future generations.
The cost of transforming an economy from one that deplete non -renewable sources o one that is in
accordance with sustainable development are considered negative externalities for future
generations. Development is limited by availability of natural resources and current development is
approaching toward a near end due to nearby exhaustion of employed resources , because
population is growing exponentially , whereas the resources and food supply is fixed. Pollution will
further limit the availability of food. Another limiting factor is depletion of natural resources. As a
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Biogas- An Alternative Source of Energy
result raw material will become extremely expensive and the depletion of non-renewable resources
will be lead to sudden collapse of economic development.
4. NEED FOR BIOGAS
Production of the “green energy” from biogas, which is among the renewable energy sources,
provides an environmentally less damaging way of obtaining energy by reducing CO2 emission in
environment. These renewable energy sources help in fighting against climate change and
contribute to economic growth, job creation and increase in energy security. Even renewable
energy technology has an impact on environment but their impact is much less than the impact of
the fossil fuels and a nuclear fuels. Global challenge of environment protection requires modified,
environment oriented energy system for future, in order to slow down greenhouse gas emission.
One of the ways must be massive effort to increase renewable energy sources such as biogas.
5. BIOGAS PRODUCTION
Anaerobic Digestion Process. Biogas, the gas generated from organic digestion under anaerobic
conditions by mixed population of microorganisms, is an alternative energy source that began to be
utilized both in rural and industrial areas at least since 1958[2]. An anaerobic treatment system is a
complex three-step process that produces methane gas in addition to other products from the
biological digestion of sewage waste. The first stage is the hydrolysis of lipids, cellulose, and
protein. Extracellular enzymes produced by the inhabiting bacteria breakdown these
macromolecules into smaller and more digestible forms. Next, these molecules are decomposed
into fatty acids such as propionic, acetic, and butyric acid. This decomposition is performed by
several facultative and anaerobic bacteria such as clostridium, bifidobacterium, desulphovibrio,
actinomyces, and staphylococcus.
Fig.1 Flow diagram of anaerobic digestion process and end points of products
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Mohd Junaid Khalil, Kartik Sharma, Rimzhim Gupta
Finally, methanogenic bacteria such as methanobacterium, methanobacillus, methanococcus, and
methanosarcina digest these fatty acids, resulting in the formation of methane gas.
The production of methane gas is the slowest and most sensitive step of the anaerobic digestion
process because it requires specific environmental conditions for the growth of methanogenic
bacteria. The methanogenic bacteria have a limited temperature range for optimum performance,
usually in the mesophilic range (32℃–40℃). Often this requires pre-heating of the waste before
entering the digester [1].
In parallel, the rate of pre-stage reaction can be optimized by applying microaeration. Typical
reactions during anaerobic digestion are [9]:
gH c jH → 2g cI jc + 2gj
2g cI jc + gj → gc + 2gc gjjc
gc gjjc → gc + gj
gj + 4c → gc + 2c j
(1)
(2)
(3)
(4)
The biogas produced in anaerobic digesters could contain methane concentrations of until 80% in
volume, and its quality would depend on its origin (drain, anaerobic digestion of residual waters, or
treatment of residuals) [4].
Parameters in Anaerobic Digestion. There are following parameters effecting the anaerobic
digestion:
Temperature. Temperature significantly influences anaerobic digestion process, especially
inmethanogenesis wherein the degradation rate is increasing with temperature [8]. It has been
found that the optimum temperature ranges for anaerobic digestion are mesophilic (30–40℃), and
thermophilic (50–60℃) [7, 6].
pH. The range of acceptable pH in digestion is theoretically from 5.5 to 8.5. However, most
methanogens function only in a pH range between 6.7 and 7.4 [5].
C/N Ratio. It is necessary to maintain proper composition of the feedstock for efficient plant
operation. Optimum C/N ratios of the digester materials can be achieved by mixing materials of
high and low C/N ratios, such as organic solid waste mixed with sewage or animal manure.
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Biogas- An Alternative Source of Energy
Retention time. The retention time is determined by the average time it takes for organic material
to digest completely, as measured by the chemical and biological oxygen demand (COD and BOD)
of exiting effluent. Retention time ranges from 30–60 days and only about 1/3 of the tank volume
is used for active digestion [9].
6. SCOPES OF BIOGAS
Today’s fast paced world is overly dependent of energy to fulfill its various requirement related to
daily life. Biogas a clean and renewable sources comes as an efficient cost effecting method to
generate power. Biogas production is clean, low carbon technology, useful for the efficient
management and conservation of organic waste into clean renewable biogas and organic
manure/fertiliser. Biogas obtain by anaerobic digestion of cattle dung and other loose leafy organic
matter / biomass waste can be used as an energy source for various application namely cooking,
heating, space cooling/ refrigeration , electricity generation and gaseous fuel for vehicular
application. Based on availability cattle dung alone from about 304million cattle, there exist an
estimated potential of about 18240 million cubic meter of biogas generation annually kitchen waste
from intuitions, universities, restaurant , parks and garden in urban area and even non edible deoiled cake from jatropha and other plant of a very large potential.
This waste must be treated to ensure reduction in methane emission affecting climate change and or
better environment condition. In addition to gas fuel, bio gas plant provides high quality organic
manure with soil nutrient which in turn improve soil fertility. Thus there is a huge scope for the
installation of medium size biogas plant in the country. This can be translated to an aggregated
estimated capacity of 8165 MW per day power generation or 2206789 LPG cylinder & 21304 lakh
kg of urea equivalent or 3974 lakh tonnes of organic manure/fertilizer per day.
7. CHALLENGES FACED IN THE BIOGAS
It is often assume that alternative energy will substitute for oil, gas ,coal, but integration of
alternative energy into our current energy system will require enormous investment in both new
equipment and new infrastructure -along with the resources consumption required for their
manufacture-at a time when capital to make such investments have become harder to secure. This
raises question of suitability of moving towards an alternative energy future an assumption that the
structure of current large scale, centralized energy system should be maintained.
Many alternative energy have been successfully demonstrated at small scale, but demonstration
scale does not provide an indication of potential for scale production because alternative energy
relies on engineering and construction of equipment and manufacturing process for its production.
His technologies that are proved feasible today will likely to have little impact until the 2030s.
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Mohd Junaid Khalil, Kartik Sharma, Rimzhim Gupta
Because alternative energy today constitute only small scale fraction of total energy production, the
volume of resources and energy demanded for its production has so far been easily accommodated.
This will necessary be the case with large scale expansion.
Alternative energy production is reliant not only on range of resource inputs, but also on fossil fuel
for mining of raw material, transport, manufacturing, construction, maintenance and
decommissioning. Currently no alternative energy exist without fossil fuel input and no alternative
energy process can reproduce itself i.e., manufacture the equipment needed for its own production
without the use of fossil fuel. The modern focus on centralized production and distribution may be
harder to maintain, since local condition will become increasingly important in determining the
feasibility of alternative energy production.
8. CONCLUSIONS
One technology that can successfully treat the organic fraction of waste is anaerobic digestion.
When used in a fully engineered system, anaerobic digestion not only provides pollution
prevention, but also allows for sustainable energy, compost and nutrients recovery.
Thus anaerobic digestion can convert a disposal problem into a profit center. As the technology
continue to mature, anaerobic digestion is becoming a key method for both waste reduction and
recovery of renewable fuel and other valuable co- products.
Biogas is produced by mean of a process known anaerobic digestion by using any organic matters
that is broken down by microbiological activity in the absence of air. Almost any organic material
is a potential source of biomass feedstock to produce biogas and the most important parameters for
the biogas generation rates are the temperature, pH, retention time, C/N ratio, particle size of the
material being digested. So these parameters should be varied within a desirable range to operate
the biogas plant efficiently.
Biogas production technology has established itself as a technology with great potential which
could exercise major influence in the energy scene in rural areas. The cost of energy produced from
biogas plant is higher than the one produced from other energy resources like oil and natural gas.
9. ACKNOWLEDGMENT
I feel fortunate enough in completing this work under the table and inspiring guidance of Dr.
Mohd. JUNAID KHALIL who very graciously supported me for completing this work
successfully. I express my deep sense of gratitude to him for his sound support and consistent
motivation throughout in completing this work.
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Biogas- An Alternative Source of Energy
REFERENCES
[1] Metcalf, Eddy. Wastewater Engineering: Treatment, Disposal, Reuse, 3rd Ed., McGraw-Hill, 1991.
[2] Anunputtikul W, Rodtong S. Laboratory scale experiments for biogas production from cassava tubers.
The Joint International Conference on “Sustainable Energy and Environment (SEE),” Hua Hin, Thailand
2004; December 1–3.
[3] Juanga J. P, Kuruparan P, Visvanathan C. Optimizing combined anaerobic digestion process of organic
fraction of municipal solid waste. International Conference on Integrated Solid Waste Management in
Southeast Asian Cities, Siem Reap, Cambodia 2005; July 5–7:155–192.
[4] Benito M, Garcia S, Ferreira-Aparicio P, Garcia Serrano L, Daza L. Development of biogas reforming
Ni-La-Al catalysts for fuel cells. J. Power Sources 2007; (169):177–183.
[5] Buekens A. Energy Recovery from Residual Waste by Means of Anaerobic Digestion Technologies.
Conference “The Future of Residual Waste Management in Europe,” Luxemburg 2005; November 17–
18.
[6] Braun R. Anaerobic digestion: a multi-faceted process for energy, environmental management and rural
development. In: Improvement of Crop Plants for Industrial End Uses, ed. P. Ranalli 2007; 335–416.
[7] Ahring B.K, Methanogenesis in thermophilic biogas reactors. Antonie Van Leeuwenhoek International
Journal of General and Molecular Microbiology 1995 ;( 67):91–102.
[8] Nguyen P.H.L, Kuruparan P, Visvanathan C. Anaerobic digestion of municipal solid waste as a
treatment prior to landfill. Bio-resource Technology 2007; 98:380–387.
[9] Ostrem K, Greening waste: Anaerobic digestion for treating the organic fraction of municipal solid
waste. M.S. Thesis, Department of Earth and Environmental Engineering, Columbia University, New
York, NY 2004.
[10] Balat M, Balat H. Biogas as a Renewable Energy Source—A Review. Energy Sources, Part A 2009;
31:1280–1293.
[11] Fatih Demirbas M, Mehmet Balat. Progress and Recent Trends in Biogas Processing. International
Journal of Green Energy, 2009; 6: 117–142.
[12] Berktay A, Nas B. Biogas Production and Utilization Potential of Wastewater Treatment Sludge. Energy
Sources, Part A 2008; 30:179–188.
[13] Zenebe Gebreegziabher, Linus Naik, Rethabile Melamu, Bedru Babulo Balana. Prospects and
challenges for urban application of biogas installations in Sub-Saharan Africa. Biomass and bioenergy
xx x (2 0 1 4) I-II.
[14] Markus Schilling, Lichun Chiang. The Depletion of Non-renewable Resources for Non sustainable
Externalities as an Economic Development Policy. CPSA Annual Conference (Canadian Political
Science Association), Carleton University in Ottawa, Canada, May 27 to May 29, 2009.
[15] Nguyen, Vo Chau Ngan. Small-scale anaerobic digesters in Vietnam - development and challenges. J.
Viet. Env. 2011; 1(1): 12-18.
[16] Chin May Ji, PohPhaikEong, TeyBengTi, Chan Eng Seng, Chin Kit Ling. Biogas from palm oil mill
effluent (POME): Opportunities and challenges from Malaysia's perspective. Renewable and
Sustainable Energy Reviews 2013; 26:717–726.
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Fuel Cell: the Future of the Electric Power System
Mamta Chamoli1, Yuvika Chamoli2
Asst. Professor (MS.)1, Lecturer( Ms.)2
Galgotias College of Engg. and Technology, Greater Noida (U.P.).
2
DIT, Dehradun (U.K.)
1
[email protected], 2 [email protected]
1
ABSTRACT
Now a day’s fuel cell is gaining wide importance in electrical sectors the entire world over. The
electrochemical devices convert the chemical energy contained in a wide variety of fuels directly
into electric energy. The electrical efficiency, of fuel cells system can be around 60%, a value
that is nearly twice the efficiency of conventional internal combustion engines. The different
types of fuels are used in fuel cells such as a natural gas, propane, landfill gas, diesel, methanol
and hydrogen. This versatility ensures that the fuel cell will not become obsolete due to
unavailability of certain fuels. The fuel cell is known connected to electrical power system and
result are simulated through MATLAB/SIMULINK Software.
Keywords: Distributed Generation, Solid Oxide Fuel Cell, RES (Renewable Energy Sources),PQ
inverters, VSI inverters
1. INTRODUCTION
Sustainable energy is the main driving force for all renewable energy sources applications. The
electrical energy in a country is largely dependent on fossil fuel, hydro fuel or nuclear fuel. The
increasing nation’s dependence on imported fossil fuels, the international political instability that
have been affecting the primary energy resources prices and the security of supply, together with
environmental concerns and climate change issues, are compromising the current energy paradigm.
The development of Distributed Generation (DG) and Renewable Electricity Generation
technologies are essential in order to achieve the proposed goals.
DG and Renewable Energy Sources (RES) cover a wide range of technologies (wind generators,
photovoltaic panels, fuel cells and micro turbines just to mention a few examples) that are suitable
for supplying power at customers sites. With the Large-scale DG, deployment will transform the
energy generation scenario from a system dominated by the centralized generation to a new one in
which environmentally friendly technologies will be adopted on large scale. The exploitation of the
DG sources can result in Deferral of investments on transmission and distribution systems.
Secondly, distribution system losses will be reduced. A better way to realize the emerging potential
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Fuel Cell: the Future of the Electric Power System
of distributed generation is to take a system approach, which views generation and associated loads
as a subsystem or a “Micro Grid”.
1 FUEL CELLS: Now a day’s fuel cell is gaining wide importance in electrical sector all the world
over. The electrochemical devices convert the chemical energy contained in a wide variety of fuels
directly into electric energy. Despite the wide range of fuel cell system advantages. The basic
element of a fuel cell is a unit cell, as shown in Figure 2(a). These basic elements convert the
chemical energy contained in fuels directly into electric energy. Each basic fuel cell unit consists of
a cathode (positively charged electrode), an anode (negatively charged electrode) and an electrolyte
layer.
Fig 2(a) Schematic Diagram of fuel Cell plant
The cathode provides an interface between the oxygen and the electrolyte catalyzes the oxygen
reaction and provides a path through which free electrons are conducted from the load to the
oxygen electrode via the external circuit. The electrolyte, an ionic conductive medium (nonelectrically conductive), acts as the separator between hydrogen and oxygen to prevent mixing and
the resultant direct combustion. It completes the electrical circuit of transporting ions between the
electrodes. Some serious shortcomings are there, one of the shortcomings is that they have very
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Mamta Chamoli, Yuvika Chamoli
high initial cost. The fuel cells systems require a certain level of purity in their supplied fuel,
making necessary the use of cleaners and filters to achieve the entailed fuel purity.
1.b) Types of Fuel Cells
There are five basic types of fuel cells under consideration for distributed generation applications,
each having different electrolytes which define the basic cell type, and a characteristic operating
temperature. Two of these fuel cell types, Polymer Electrolyte Membrane Fuel Cell (PEMFC) and
Phosphoric Acid Fuel Cell (PAFC) have acidic electrolytes and rely on the transport of H+ ions.
Figure 2(b) Basic processes in a Fuel Cell Power Plant
A Solid Oxide fuel Cell (SOFC) is considered now a days, for stationary power generation
applications due to the following advantages:
The fuel processor requires a simple partial oxidation reforming process, eliminating the need of an
external reformer. SOFC has relatively low requirements for the fuel reformation process. It can
use carbon monoxide directly as a fuel, which do not require a very sophisticated reformer. As it
operates at extremely high temperatures, it can tolerate relatively impure fuels.
The SOFC being a high temperature fuel cell entails some major drawbacks. Due to the hightemperature operation, it requires a significant time to reach the operating temperature and to
respond to changes in the output power. The start-up time is in the order of 30 to 50 minutes. This
SOFC dynamic model is also adopted in this work and is it based on the following assumptions:
The gases are ideal. Assuming that the SOFC system is supplied with hydrogen in the anode and
oxygen in the cathode, the reactions that take place are described by the following equations:
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Fuel Cell: the Future of the Electric Power System
Anode: H2 + O═ → H2O + 2e─
Cathode: O2 + 2e─ → O
In order to calculate the open circuit voltage E of a stack with No cells connected in the series, the
Nernst equation is used:
E = N
o

E

o
+
p
RT
In
2F
po2 

p h2o

H 2
-------------------------------
(1)
Where Eo: voltage associated with reaction free energy of the cell (V)
R: universal gas constant (8314.51 J.kmol-1.K-1)
T: channel temperature (assumed to be constant) (K)
F: Faraday constant (96.487×106 C. kmol-1)
po2, pH2o, pH2 : partial pressures of hydrogen, oxygen and water vapour, respectively (atm).All the
reactions occurring in the fuel cell stack have some inherent time delays. The chemical response in
the fuel cell processor is usually slow and it is associated with the time to change the chemical
reaction parameters after a change in the flow of reactants. This dynamic response function is
modelled, as a first order, transfer function with a time delay Tf . The Figure 2.3 shows block
diagram of the adopted SOFC dynamic model.
Fig.2.3 Simulation of Solid Oxide Fuel Cell
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2. SIMULATION OF MICROGRID COMPONENTS
The figure 3.0 shows the Simulation of the Micro Grid components the dynamic simulation
platform was developed under the MatLab /Simulink environment. In the simulation platform it is
possible to analyse the dynamic behaviour of several Micro sources (Solid Oxide fuel Cell) and its
connection to PQ inverters. Here in the given Fig.3.0 the dynamic model of Solid Oxide fuel Cell is
being described.
Figure 3.0: Simulation of Fuel Cell
The Solid Oxide fuel consisting of the three parts fuel processor, power section and power
conditioner .The Solid Oxide fuel Cell is developed in a modular way where the control parameters
and models are included in a Matlab/ Simulink.The parameters of the Solid Oxide fuel Cell are
included in appendix .A The Fig.3.1 shows the results of the active power’s time.
Figure 3.1: Solid Oxide fuel Cell
time. The Figure 3.2 show the PQ control of the inverter is shown here in it is implemented as a
current controlled voltage source as shown in the Figure 3.3. Current components in phase (iact) and
quadrature (ireact) with the inverter terminal voltage are computed as similar to single phase
inverters. Power variation in MS induces a dc-link voltage error corrected via the PI-I regulators by
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Fuel Cell: the Future of the Electric Power System
adjusting the magnitude of the active current output delivered to the grid. The reactive power
output is controlled via PI-2 regulator by adjusting the magnitude of the inverter reactive current
output.
Figure 3.2: PQ Control of the Inverter
The Figure 3.3 shows the waveform of the PQ control of the inverter & load.
Figure 3.3: Waveform of the PQ Controlled Inverter
3. RESULT DISCUSSION
The Dynamic Simulation of the Solid Oxide fuel Cell, and PQ control of inverters are shown and
the result obtained are compared with the result of the paper [2]. The active power graph shown in
the Fig .3.0 Fig 3.1 shows the local PI control. In order to analyses the behaviour of an MG, the
dynamics of the primary energy sources are neglected due to the high storage capacity assumed to
be installed at their dc link. Due to the existence of a high storage capacity, the system frequency is
restored faster to its nominal value. The PQ inverter is used to supply given active and reactive set
points.
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4. CONCLUSION
In this work study of the Micro Grid Concept has been made. The Micro Grid consists of a low
voltage distribution network with distributed energy sources (the Micro sources) together with
storage devices and controllable loads, operating in a controlled coordinated way through the use of
advanced management and control systems supported by a communication.
REFERENCES
[1] Fang.Gao” A Control Strategy for a Distributed Generation unit in Grid connected and autonomous
modes of operation.” IEEE Transactions on Power Systems.vol.23 no.2, pp-850-859 April 2008.
[2] J.A Pecas Lopes C.L Moreira, and AG Madureia “Defining Control Strategies for Micro Grids Islanded
Operation.” IEEE Transcations on Power Systems.vol.21 no.2, pp-916-920 May 2006.
[3] F.Katirae” MicroGrid Autonomous Operation during and subsequent to islanding process. “IEEE
Transcations on Power systems. vol.20.no.1, pp-248-257 January 2008.
[4] J.A. Peças Lopes, N. Hatziargyriou, J. Mutale, P. Djapic, and N. Jenkins, "Integrating distributed
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[6] Y. Zhu and K. Tomsovic, "Development of models for analyzing the load-following performance of
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[7] J. Padullés, G. W. Ault, and J. R. McDonald, "An integrated SOFC Plant dyamic model for power
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[8] Cashing Wang “A Physically based dynamic model for Solid Oxide fuel Cell” IEEE Transactions on
Energy Conversion, vol. 22, no. 4, and pp.887-896. December 2007.
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The State of Art of MEMS in Automation Industries
Anupriya Saxena1, Man Mohan Singh2 and Indra Vijay Singh3
1
M.Tech Student, Satya College of Engg. & Tech., Palwal, Haryana
2
Research Scholar, Aligarh Muslim University, Aligarh, UP
3
Institute of Technology and Management, Aligarh, UP
ABSTRACT
In this paper we present the comparison of MEMS Technology with previous technology in
automation industries. These comparisons make use in analyzing the production rate, cost, down
time and energy wastage of an industry. The main objective of our comparison is to adopt and
implement the MEMS technology to conserve energy as well as time. It makes direct effect on
production rate of organization as we use MEMS /NANO sensors along with fuzzy logic which
gives more accurate and efficient design. Furthermore, it uses datasheets of small scale
industries in Aligarh which can take care of more reliable results. Comparison has been taken
through original data which confirms the idea present in it. Through this study we analyzed that
the implementation of automation increase production rate, plant capacity and at the same time
conserve energy.
Keywords: Automation, MEMS, Nano Sensors, Energy Conservation.
1. INTRODUCTION
Nowadays, Micro-Electromechanical Systems (MEMS) plays a key role in the field of automation
industries. In the context of automation, electrical and mechanical systems are combined,
controlled by microchips and fabricated on silicon wafers. The main components of automotive
electronic control systems are Sensors and actuators [1]. So we require a control system for sensors
and actuators design and it provide by MEMS/Nano technology. Similarly, growth through
significant new technologies has been achieved with MEMS in an automation industry [2].
An influential business which leads to a new direction is an Industrial automation [3]. As new
technologies come day by day, we have to make a prominent technology which has remarkable
throughput among all technologies with small size and economical to an organization [4]. Hence,
industries have started traversing new technologies and opportunities in the field of industrial
automation; one such technology is micro electro mechanical systems (MEMS). Automation is use
of various control system for operating equipment’s such as boilers, machinery, switching
networks, processes in factories and other application with minimal or reduced human
interventions.
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Anupriya Saxena, Man Mohan Singh and Indra Vijay Singh
Present era can be defined as automation revolution, which is spreading in industries and industrial
development and become a boon for it. Hence, a part of this Technology is MEMS which provides
a new concept, new direction, new innovation and many opportunities.
Remainder of this paper is organized as follows. Second section discussed the basic mechanism of
MEMS and its advantages. MEMS for industrial automation discussed in third section. Fourth
section discussed the result & comparison analysis. Finally, last section concludes the paper.
2. MEMS MECHANISM AND ITS ADVANTAGES
A micro fabrication technology on common silicon substrate is being integrated with mechanical
elements, actuators, sensors and electronics be called as micro electromechanical systems (MEMS)
[5]. A numbers of methodologies along with tools together form a small structure in the dimensions
of micrometre scale. The most important part of any system is brain, here are microelectronic
integrated circuits. MEMS are eyes and the supporting arms associated with the microsystems to
sense are control systems.
Mechanism of MEMS system describes the overall functioning of the systems. Information is
gathered by sensors through environment with the help of mechanical, optical, thermal, chemical
and magnetic phenomenon. And this information gives to the integrated circuits and these circuits
make a control system to control various parameters which are responsible for the proper
functioning of any micro electro-mechanical system.
Fig.1: Flow view of the advantages of MEMS Technology.
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The State of Art of MEMS in Automation Industries
The Advantages with the use of these MEMS technology are easily shown with the help of fig.1.
Here, sensitivity and the small size of the device are the key points of this technology [6]. As we all
know the size of the device is too important for functioning of the device and sensitivity plays an
important role in the better efficiency of any system.
3. MEMS FOR INDUSTRIAL AUTOMATION
The interdisciplinary nature of MEMS relies on engineering, design and manufacturing from a
wide range of technical areas. These areas including material science, control systems, sensors,
integrated circuits, mechanical and electrical engineering [7]. Despite all, MEMS requires
microcontrollers which are dedicated to functioning of the design. With numbers of
interdisciplinary areas, complexity of MEMS increases but accuracy also be increased. Control
system plays an important role in designing these systems along with integrated circuits. Electronic
integrated circuits fabricates at a very high cost, so cost of these devices slightly increases.
MEMS design is very sophisticated due to advanced semiconductors technology; it requires
mechanical moving parts as well as electrical design of the device. It brings many technologies
together in electronics like Complementary Metal oxide Semiconductor (CMOS), Bi-CMOS
(Integration of Bipolar junction transistor and CMOS technology), Silicon on Insulator (SOI),
Pipelining and fabricated on single chip.
The sensitivity, reliability, scalability with cost effective design has offered by MEMS technology.
It provides more opportunities in the field of automation. An industry relies on these technologies
for higher throughput and production rate with less time. Humidity check control, pressure control
and much such type of measurement meters has available in the markets for increasing the
accuracy and quick in nature. As MEMS technology increases now-a-day, we studied this
technology and conclude in the form of a table shown below. In this table, we justified that the
increasing rate of MEMS technology in automation industries goes beyond nanotechnology by next
decade.
Table 1: Growth rate of MEMS technology from stabilizers to Nano-sensors.
Years
Applications
2007
2008
ABS
(cars),electronic
stabilization, lowend
industrial
application
Air condition,
refrigeration
and
micro
fluids
2009
2010
Large array Desktop
and MEMS MEMS
device on a factory
single
substrate
2015
Nano
Manufacturing
and
Nano
Factory
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Anupriya Saxena,, Man Mohan Singh and Indra Vijay Singh
4. RESULT ANALYSIS
With the help of this technology we compare many parameters in an automation industry. These
parameters named as production rate, cost, down time and energy wastage in the small scale
industry. Firstly we compared the down time and wastage of energy in a company with both
technologies and shown with the help of graph as shown in fig.2. Similarly,
Simil
fig.3. shows the
comparison of the cost and the productivity of the industry.
3
80
2.5
70
60
2
Old
Technology
1.5
Using MEMS
1
50
old
technology
using MEMS
40
30
20
0.5
10
0
0
Down Time
Energy Wastage
Fig.2: Comparison of down time
and Energy wastage
Cost
Productivity
Fig.3: Comparison of Cost
and Productivity
Another comparison of these technologies is shown in fig.4 and
an fig.5. This comparison shows the
reduction of break down time with energy losses in an industry.
OLD TECHNOLOGY
USING MEMS
Down Time
Down Time
Energy
Wastage
Energy
Wastage
Break Down
Time
Break Down
Time
Production
Time
Production
Time
Fig.4. Comparison of various parameters between old technologies and MEMS
Emerging Energy Technology perspectives-A
A Sustainable Approach - ISBN: 978-93-83083-73-2
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The State of Art of MEMS in Automation Industries
These results of comparison show that MEMS technology provides a new concept, new direction,
new innovation and many opportunities in automation industries. MEMS reduce the labor efforts,
reduce production time, break down time and increase the overall productivity of an industry.
These data has been taken from the small scale industries of Aligarh.
5. CONCLUSION
From this Study, following significant conclusions can be drawn.
1.
The Total Productivity of an Industry was found to be increased upto 20 percent.
2.
Improvement in Production rate was observed by applying Automation and MEMS
technology over the previous technologies. With the application of MEMS we found an
increment of 12-15% in Total Production rate.
3.
The use of MEMS technology introduces compactness and reduces human efforts, with
maximum accuracy and sensitiveness.
MEMS Technology is safe and secure and can be applied in Industries for achieving better
Production Rates. Also, the technique requires less effort and is cost effective.
6. ACKNOWLEDGEMENTS
The authors of this paper are grateful to the University Polytechnic, Aligarh Muslim University.
REFERENCES
[1] David S. Eddy and Douglas R. Sparks, “Application of MEMS Technology in Automotive sensors and
Actuators”, proceedings of the IEEE, vol. 86, no. 8, august 1998.
[2] D. Sparks, D. Riley, N. Tran, A. Chimbayo, K. Kawaguchi and M. Yasuda, “Embedded MEMS-based
concentration sensor for improved active fuel Cell performance”, 14th International Conference on
Solid-State, Actuators and Microsystems, Lyon, France, June 10-14, 2007.
[3] Henne van Heeren, Jeremie Bouchaud, Richard Dixon and Patric Salomon, “Rewards and Risks of
Moving into New Applications: Case Study Accelerometers” MSTnews, February 2007.
[4] Liang Lou, Kotlanka Ramakrishna, Lichun Shao, Woo-Tae Park, Daquan Yu, Lishiah Lim, Yongjun
Wee, “Sensorized guidewires with MEMS tri-axial force sensor for minimally invasive surgical
applications”, 32nd Annual International Conference of the IEEE EMBS Buenos Aires, Argentina,
August 31 - September 4, 2010.
[5] Doug Sparks, “Reliable MEMS Vacuum Packaging for Aerospace Applications”, MEMS & Sensors for
Aerospace Applications, April 2010.
[6] D. Sparks, S. Massoud, Ansari, N. Najafi, “Chip-Level Vacuum Packaging of Micromachines Using
NanoGetters”, IEEE Transactions on Advanced Packaging, Vol. 26, Aug. 2003.
[7] Masako Tanaka, “An industrial and applied review of new MEMS devices features”, Proceedings of the
32nd International Conference on Micro- and Nano-Engineering, Volume 84, Issues 5–8, May–August
2007.
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Dynamic Economic Power Dispatch
Problem Using Differential Evolution
Nandan Kumar Navin1, Sonam Maheshwari2
1,2
PG Scholar
Department of Electrical and Instrumentation Engineering, THAPAR UNIVERSITY PATIALA, India
1,2
ABSTRACT
The DED problem is an optimization problem with an objective to determine the optimal
combination of power outputs for all committed generating units over a certain period of time in
order to minimize the total fuel cost while satisfying dynamic operational constraints and load
demand in each interval. The differential evolution (DE) algorithm is a powerful evolutionary
algorithm for global optimization in real problems, which only has a few control parameters and
has been successfully applied to a wide range of optimization problems. The economic operation
of the generating systems has always occupied an important position in the electric power
industry. It is one of the complex problems of the power system. The aim of the dynamic
economic load dispatch problem is to find the optimal combination of generators in order to
minimize the operating costs of the system. The load demand must be appropriately shared
among the various generating units of the system. Ten-unit test systems with non-linear
characteristics of the generators are considered to illustrate the effectiveness of the DE method.
Keywords: Dynamic economic load dispatch, Differential Evolution, generator constraints
1. LITERATURE SURVEY
Dynamic economic dispatch (DED) is a method to schedule the online generator outputs with the
predicted load demands over a certain period of time so as to operate an electric power system most
economically [1]–[7].
The DED is not only the most accurate formulation of the economic dispatch problem, it is also the
most difficult dynamic optimization problem. Most of the literature addresses DED problems with
convex cost functions [1, 2, 3, and 4].The large steam turbines have steam admission valves, which
contribute non-convexity in the fuel-cost function of the generating units [5]. Accurate modeling of
the DED problem will be improved when the valve-point loadings in the generating units are taken
into account. Furthermore, they may generate multiple local optimum points in the solution space.
Previous efforts to solve the DED problem have employed various mathematical programming
methods and optimization techniques. When traditional methods (such as the gradient projection
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Dynamic Economic Power Dispatch Problem Using Differential Evolution
method [1], Lagrangian relaxation [6], dynamic programming, etc.) are used to solve the DED
problem, they often use approximations to limit complexity, and they also frequently suffer from
myopia for non-linear practical systems, which leads them to a less-desirable performance. The
stochastic search algorithms (such as particle swarm optimization (PSO) [5], genetic algorithm
(GA) [7], evolutionary programming (EP) [8, 9], simulated annealing (SA) [10, 11], and the tabu
search algorithm (TSA) [12]) may prove to be very effective in solving non-linear economic
dispatch problems without any restriction on the shape of the cost curves. Although these heuristic
methods do not always guarantee discovering the globally optimal solution in finite time, they
often provide fast, reasonable, and near global optimal solutions .DED is a dynamic problem, due
to the dynamic nature of the power system and the large variation of load demand. This problem
can be solved by dicretization of the entire dispatch period into a number of small intervals, over
which the load is assumed to be constant, and the system is considered to be in temporal steady
state. Recently, hybrid EP-sequential quadratic programming (SQP) [13], deterministically guided
PSO [14], and hybrid PSO-SQP [15] methods were proposed to solve the DED problem with nonsmooth fuel cost functions. These hybrid methods utilize the local searching property of SQP along
with stochastic optimization techniques to determine the optimal solution of the DED problem. SA
[16] has also been employed for the solution of the DED problem. All of these methods utilize the
traditional approach of a DED in which power generation is coordinated for the entire dispatch
period, which makes the problem a heavily constrained optimization problem. Differential
evolution (DE) is a robust statistical method for cost function minimization that does not make use
of a single parameter vector but instead uses a population of equally important vectors [17]. In this
paper, a simplified approach based on a DE algorithm is developed to find the optimum generation
schedule of the DED problem including valve-point effects. Differential evolution (DE) is arguably
one of the most powerful stochastic real-parameter optimization algorithms in current use. DE
operates through similar computational steps as employed by a standard evolutionary algorithm
(EA).
2. FORMULATION OF DYNAMIC ECONOMIC LOAD DISPATCH PROBLEM
2.1 Objective Function
The main objective of the economic load dispatch is to reduce the operating costs or the generation
costs of the system while satisfying the various system constraints. The DELD problem is
formulated to find the optimal combination of the generators while satisfying the consumer load
demands and also satisfying the various equality and inequality constraints.
The objective function of DELD problem is expressed as sum of fuel cost. The fuel cost function of
unit i at hour t is expressed as a second order polynomial.
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Nandan Kumar Navin, Sonam Maheshwari
=mno = p p oq,D r"q,D s,1)
Du qu
Where F = the total generating cost over the whole dispatch period
T= the number of intervals in the scheduled horizon
N= the number of generating units
oq,D r"q,D s = The fuel cost in terms of its real power output "q,D at time t
Taking into account of the valve-point effects, the fuel cost function of the v Dw thermal generating
unit is expressed as the quadratic function in the form as given below:
oq,D r"q,D s = xq × "q,D
+ yq × "q,D + zq ,2)
Where xq , yq , x{(zq = fuel cost coefficients
"q,D = The power output of the v Dw unit in MW
2.2 System Constraints:There are two types of constraints in DELD Problem.
Equality constraints
Inequality constraints
Equality Constraints
(1) Power Balance Constraint
The sum of the unit generation output at each hour must satisfy the system load demand
requirement of the corresponding hour as follows:
p "q,D = "6,D ,3)
qu
Where "6,D = Total power demand at hour t
"q,D = Power generated by unit i at hour t
2.2.2 Inequality Constraints
(1) Generations Limit Constraints
The power produced by each unit must be within certain limits, as indicated below:
"qq} ≤ "q,D ≤ "q€ ,4)
Where "qq} , "q€ the minimum and maximum generations are limits of unit i respectively.
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Dynamic Economic Power Dispatch Problem Using Differential Evolution
3. DIFFERENTIAL EVOLUTION ALGORITHM
3.1 Overview of Differential Evolution (DE)
Differential Evolution (DE) is an evolutionary algorithm based on the populations of possible
candidate solutions with three operators: mutation, crossover and selection. In DE candidate
solutions are identified by vectors and set of vectors generate the population. The basic notion is to
form new vector by means of the weighted difference between the two population vectors. These
three vectors are chosen randomly. Then the fitness of new vector is checked. If the fitness of the
last vector is better than the previous two, then the exchange takes place.
The performance of DE is heavily dependent on the setting of control parameters. Proper selection
of control parameters is very important for the success of the algorithm. An optimal setting of
control parameters of DE depends on the specific problem under consideration.
3.1.1 Initialization
The basic step in DE optimization is to create an initial population of candidate solutions by
assigning random values to each decision parameter of each individual of the population. A
population P consisting of n individuals is constructed in a random manner such that the value
lies within the feasible bounds "‚q} and "‚€ of the decision variable, according to the following
rule:
"q,‚ = "‚q} + ƒx{( × r"‚€ − "‚q} s,5)
Where i= 1, 2,..…, n Denotes the individual’s population index
j=1, 2,….,D Signifies the D-dimensional search space position
"‚q} =Lower bound of the decision variable
"‚€ =Upper bound of the decision variable
ƒx{(= A uniformly distributed random number varies between 0 to 1
3.1.2 Mutation
Next generation offspring are introduced into the population through the mutation process.
Mutation is performed by choosing three individuals from the population "}… in a random
manner. Let "Y , "Y† , "Y‡ represent three random individuals such that ƒx ≠ ƒy ≠ ƒz ≠ v upon
which mutation is performed during the ‰ Dw generation as:
eq
,Š)
,Š)
,Š)
,Š)
= "Y + ‹Œ × "Y† − "Y‡ Ž,6)
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Nandan Kumar Navin, Sonam Maheshwari
3.1.3 Crossover
New offspring members are reproduced through the crossover operation based on binomial
Š
distribution. The members of the current population (target vector) "q,‚
and the members of the
,Š)
mutated individual eq,‚
,Š)
are subjected to crossover operation thus producing a trial vector q,‚
according to following rule:
Š
= ‘
q,‚
Š
eq,‚
, v‹ƒx{(#0,1' ≤ gY
Š
"q,‚
,’&ℎ”ƒ•v/”
– ,7)
Where gY is the crossover constant that controls the diversity of the population and prevents the
algorithm from getting trapped into the local optima. The crossover constant must be in the range
of [0, 1].
3.1.4 Selection
Selection procedure is performed with the trial vector and the target vector to choose the best set of
individuals for the next generation. In this proposed approach, only one population set is
maintained and hence the best individuals replace the target individuals in the current population.
The objective values of the trial vector and the target vector are evaluated and compared. If the trial
vector has better value, the target vector is replaced with the trial vector as per the following rule:
 Š , v‹‹rqŠ s ≤ ‹r"qŠ s
"qŠ = ‘ q
,8)–
"qŠ ,’&ℎ”ƒ•v/”
4. DIFFERENTIAL EVOLUTION ALGORITHM FOR DED PROBLEM
The detailed implementation of the DE algorithm to find a solution for the DED problem is given
below.
Step 1: Read data, viz. Cost coefficient ( xq , yq , zq ), population size (L), boundary constraints of
optimization variables (NG), mutation factor (FM), crossover rate (CR), and the stopping criterion
of maximum number of iterations (m$€ ),"qq} , "q€ .
Step 2: Randomly generate an initial population of each individuals using Eq. (9).
Step 3: Calculate the fitness of each individuals of initial population (target vector matrix) using
Eq. (13), which is the total production cost of all units of the system.
=mno = p p oq,D r"q,D s + μ × šp p "q,D − "6,D › ,13)
Du qu
Du qu
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Dynamic Economic Power Dispatch Problem Using Differential Evolution
Flow Chart of DE
A
Start
Yes
Read the parameters – Scaling factor
FM, Crossover constant CR,
Population size L, Maximum
Iteration m$€ ,Number of generators
N
Is
IT>m$€
Print the
No
Set the iteration counter IT =IT+1
Set the iteration counter IT =0
Set the population index j=1
Set the population index j=1
Set the decision variable i= 1
Set the decision variable i= 1
Perform mutation
,‰+1)
ev
Initialize the parent vectors uniformly in
the random search space
"v,œ = "Œv{
+ ƒx{( × r"Œx
− "Œv{
œ
œ
œ s
v = v +No
1
Is i >N?
No
Is
i>N?
Yes
× "
,‰ )
− ",‰) Ž
No
v =v+1
Yes
No
Yes
œ =œ+1
,‰)
= "ƒx + ‹Œ
Is j>NP?
Find the fittest parent vector
among entire population & set
it as the target vector
Yes
Is
j>NP?
œ =œ+1
Perform crossover
A
‰+1
=‘
v,œ
e‰+1
v,œ , v‹ƒx{(#0,1' ≤ gƒ
"‰+1
v,œ ,’&ℎ”ƒ•v/”
–
Perform selection
"qŠ
 Š , v‹‹,qŠ ) ≤ ‹,"qŠ )
= ‘ qŠ
"q ,’&ℎ”ƒ•v/”
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Nandan Kumar Navin, Sonam Maheshwari
Step 4: Select the maximum fitness of the initial population, i.e., the minimum cost of production
†7D
of the initial population and set as cost is o‚†7D and"‚,q,D
= "‚,q,D .
Step 5: Set iteration IT=1
Step 6: Perform mutation operation on initial population using Eq. (10).
Step 7: Calculate the fitness of each individuals of donor vector matrix using Eq. (13).
Step 8: Perform crossover operation on initial population using Eq. (11)
Step 9: Calculate the fitness of each individuals of trial vector matrix using Eq. (13).
Step 10: If fitness of the trial vector matrix is greater than or equal to the fitness of the target vector
matrix, then the target vector matrix is replaced by the trial vector matrix using Eq. (12), otherwise,
the target vector matrix remains the same.
Step 11: Calculate the new objective value by Eq. (13) and set as cost iso‚}… .
†7D
}…
Step 12: If (o‚}… < o‚†7D ) THEN set (o‚†7D = o‚}… ) and ("‚,q,D
= "‚,q,D
)
Step 13: If the iteration is less than the maximum iteration m$ < m$€, m$ = m$ + 1 and return to
step 5
†7D
Step 14: STOP and o‚†7D &"‚,q,D
give the optimum output.
5. NUMERICAL SIMULATION RESULTS AND CONCLUSION
Test System: The cost coefficients, generation limits, load demand in each interval of a ten unit
system is taken from [16].
Input data for ten generating units and 24–hour scheduling
Unit 1
Unit 2
Unit 3
Unit 4
Unit 5
Unit 6
Unit 7
Unit 8
Unit 9
Unit 10
Ÿ ¡¢ (MW)
455
455
130
130
162
80
85
55
55
55
Ÿ £¤ (MW)
150
150
20
20
25
20
25
10
10
10
a($/MW2 h)
0.00048 0.00031 0.002
0.00211 0.00398 0.00712 0.00079 0.00413 0.00222 0.00173
b($/MW h)
16.19
17.26
16.60
16.50
19.70
22.26
27.74
25.92
27.27
27.79
c($/h)
1000
970
700
680
450
370
480
660
665
670
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Dynamic Economic Power Dispatch Problem Using Differential Evolution
Load Demand for 24 hr
Time
(hr)
1
2
3
4
Load
(MW)
700
750
850
950
Time
(hr)
5
6
7
8
Load
(MW)
1000
1100
1150
1200
Time
(hr)
9
10
11
12
Load
(MW)
1300
1400
1450
1500
Time
(hr)
13
14
15
16
Load
(MW)
1400
1300
1200
1050
Time
(hr)
17
18
19
20
Load
(MW)
1000
1100
1200
1400
Time
(hr)
21
22
23
24
Load
(MW)
1300
1100
900
800
6. OPTIMAL SCHEDULING OF THE GENERATING UNIT (TEST SYSTEM):
Power Generations of Units(MW)
Power Hourly
Hour Demand Operating
Unit Unit Unit Unit Unit
(MW) cost($)
Unit 1 Unit 2 Unit 3 Unit 4 Unit 5
6
7
8
9
10
1
700
19874
152.14 213.27 24.55 130
2
750
20739
146.53 235.23 88.62 101.08 55.34 31.97 25
3
850
22338
148.35 201.82 60.22 130
86.93 72.80 61.12 46.33 32.39 10
4
950
23704
220.43 423.17 53.99 20
49.69 51.86 25
5
1000
24768
267.82 450.54 31.16 79.31 25
6
1100
26536
455
233.88 86.82 42.36 93.49 20
7
1150
27310
455
281.90 130
86.90 25
8
1200
28393
455
349.29 130
20
9
1300
30024
455
427.38 130
84.53 70.98 29.54 25
10
1400
32302
455
395.57 130
81.38 98.52 66.82 69.81 37.91 24.39 40.16
11
1450
33240
455
455
12
1500
49275
455
405.11 130
13
1400
32125
447.27 433.43 114.75 128.06 96.69 72.04 49.85 21.06 18.30 18.48
14
1300
30379
454.68 454.13 67.21 35.19 156.65 25.37 33.51 18.80 38.34 16.08
15
1200
28342
348.46 447.12 108.75 64.43 25
74.25 25
36.11 43.87 26.97
16
1050
25603
434.73 217.92 95.12 107.71 41.55 75.83 25
18.12 20.86 13.11
17
1000
24683
347.63 266.42 130
85.22 130
130
39.80 28.38 32.13 37.71 10
78.97 25
31.98
40.17 15.26 10.75
33.23 17.59 55
10
10
22.16
48.33 44.19 47.63 28.21
44.37 38.40 42.29 22.96 22.50
43.98 27.02 81.20 25.86 33.50 33.94
21.87 32.27 23.38
157.42 37.16 48.79 16.37 55
10
136.90 53.80 55.29 48.05 41.10 44.10
75.76 57.08 43.11 25.50 28.67 10
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15.80
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Nandan Kumar Navin, Sonam Maheshwari
18
1100
26510
322.05 452.83 27.16 115.21 45.59 66.95 32.30 15.66 10.79 11.42
19
1200
28031
446.95 297.84 129.87 53.31 124.30 20
20
1400
32430
455
21
1300
30152
252.67 392.20 127.50 130
22
1100
26083
247.88 455
23
900
22863
310.62 241.49 20
24
800
21298
173.07 237.24 72.11 32.52 59.12 74.95 30.95 10
455
84.82 22.88 10
10
75.87 127.70 105.09 34.11 56.88 29.32 50.83 10
127.83 63.81 71.67 38.89 47.57 47.81
21.73 124.02 49.73 80
79.66 66.03 20
85
16.62 10
10
72.27 22.63 15.41 51.85
55
55
Total minimum generating cost ($/day) = 667002
7. CONCLUSION
In this paper, the dynamic economic load dispatch problem (DELD) is solved using a robust DE
algorithm. The maximum penalty factor method is used to incorporate the cost penalty. The
performance of DE was tested on a system of ten generating units. The proposed method utilizes
the conventional ELD approach in each interval of the scheduling horizon .The proposed DE-based
dynamic procedure provides an optimal solution with an acceptable computation time.
REFERENCES
[1] Granelli, G. P., Marannino, P., Montagna, M., and Silvestri, A., “Fast and efficient gradient projection
algorithm for dynamic generation dispatching,” IEE Proc. Generat. Transm. Distrib., Vol. 136, No. 5,
pp. 295–302, September 1989.
[2] Li, F., Morgan, R., and Williams, D., “Hybrid genetic approaches to ramping rate constrained dynamic
economic dispatch,” Elect. Power Syst. Res., Vol. 43, No. 2, pp. 97–103, November 1997.
[3] Han, X. S., Gooi, H. B., and Kirschen, D. S., “Dynamic economic dispatch: Feasible and optimal
solutions,” IEEE Trans. Power Syst., Vol. 16, No. 1, pp. 22–28, February 2001.
[4] Attaviriyanupap, P., Kita, H., Tanaka, E., and Hasegawa, J., “A fuzzy-optimization approach to dynamic
economic dispatch considering uncertainties,” IEEE Trans. Power Syst., Vol. 19, No. 3, pp. 1299–1307,
August 2004.
[5] Gaing, Z.-L., “Particle swarm optimization to solving the economic dispatch considering the generator
constraints,” IEEE Trans. Power Syst., Vol. 18, No. 3, pp. 1187–1195, August 2003.
[6] Hindi, K. S., and Ab Ghani, M. R., “Dynamic economic dispatch for large scale power systems: A
Lagrangian relaxation approach,” Elect. Power Energy Syst., Vol. 13, No. 1, pp. 51–56, February 1991.
[7] Walters, D. C., and Sheble, G. B., “Genetic algorithm solution of economic dispatch with valve-point
loadings,” IEEE Trans. Power Syst., Vol. 8, No. 3, pp. 1325–1331, August 1993.
[8] Yang, H. T., Yang, P. C., and Huang, C. L., “Evolutionary programming based economic dispatch for
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112–118, February 1996.
[9] Sinha, N., Chakrabarti, R., and Chattopadhyay, P. K., “Evolutionary programming techniques for
economic load dispatch,” IEEE Trans. Evol. Computat., Vol. 7, No. 1, pp. 83–94, February 2003.
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[10] Wong, K. P., and Wong, Y. W., “Genetic and genetic/simulated-annealing approaches to economic
dispatch,” IEE Proc. Generat. Transm. Distrib., Vol. 141, No. 5, pp. 507–513, September 1994.
[11] Simopoulos, D. N., Kavatza, D., and Vournas, C. D., “Unit commitment by an enhanced simulated
annealing algorithm,” IEEE Trans. Power Syst., Vol. 21, No. 1, pp. 68–76, February 2006.
[12] Lin, M. M., Cheng, F. S., and Tsay, M. T., “An improved tabu search for economic dispatch with
multiple minima,” IEEE Trans. Power Syst., Vol. 17, No. 1, pp. 108–112, February 2002.
[13] Attaviriyanupap, P., Kita, H., Tanaka, E., and Hasegawa, J., “A hybrid EP and SQP for dynamic
economic dispatch with non smooth fuel cost function,” IEEE Trans. Power Syst., Vol. 17, No. 2, pp.
411–416, May 2002.
[14] Victoire, T. A. A., and Jeyakumar, A. E., “Deterministically guided PSO for dynamic dispatch
considering valve-point effect,” Elect. Power Syst. Res., Vol. 73, No. 3, pp. 313–322, March 2005.
[15] Victoire, T. A. A., and Jeyakumar, A. E., “Reserve constrained dynamic dispatch of units with valvepoint effects,” IEEE Trans. Power Syst., Vol. 20, No. 3, pp. 1273–1282, August 2005.
[16] Panigrahi, C. K., Chattopadhyay, P. K., Chakrabarti, R. N., and Basu, M., “Simulated annealing
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Emission Constrained Economic Load Dispatch Problem
Using Differential Evolution Algorithm
Nandan Kumar Navin
(PG Scholar)
Department of Electrical and Instrumentation Engineering, THAPAR UNIVERSITY, PATIALA, India
ABSTRACT
The emission constrained economic load dispatch (ECELD) problem is a sub problem of an
optimal power dispatch. In this paper, Differential Evolution (DE) based optimization technique
is presented to solve the emission constrained economic load dispatch (ECELD) problem which
is a nonlinear function of generated power. DE is a population based stochastic search
technique that works in the general framework of Evolutionary Algorithms. The design
principles of DE are simplicity, efficiency and use of real coding. Traditionally electric power
systems are operated in such a way that the total fuel cost is minimized regardless of emissions
produced. With increased requirements for environmental protection, alternative strategies are
required. The DE algorithm attempts to reduce the production of atmospheric emissions such as
sulfur oxides and nitrogen oxides, caused by the operation of fossil-fueled thermal generation.
Such reduction is achieved by including emissions as a constraint in the objective of the overall
dispatching problem.
Keywords: Economic power dispatch, Differential evolution algorithm, Fuel cost minimization,
Emission constraint, Environmental issues
1. LITERATURE SURVEY
The basic objective of economic load dispatch (ELD) of electric power generation is to schedule
the generation unit outputs so as to meet the load demand at minimum operating cost while
satisfying all unit and system equality and inequality constraints [1,2]. The literature of the ELD
problem and its solution methods are surveyed in [3]. The generation of electricity from fossil fuel
releases several contaminants, such as sulfur oxides, nitrogen oxides and carbon dioxide, into the
atmosphere. Recently the problem which has attracted much attention is pollution minimization
due to the pressing public demand for clean air. Since the text of the Clean Air Act Amendments of
1990 and similar acts by European and Japanese governments, environmental constraints have
topped the list of utility management concerns [4]. Several strategies to reduce the atmospheric
emissions have been proposed and discussed. These include installation of pollutant cleaning
equipment, switching to low emission fuels, replacement of the aged fuel-burners with cleaner
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Emission Constrained Economic Load Dispatch Problem Using Differential Evolution Algorithm
ones, and emission dispatching. The first three options require installation of new equipment and
modification of the existing ones that involve considerable capital outlay and, hence, they can be
considered as long-term options. The emission dispatching option is an attractive short-term
alternative in which both emission and fuel cost is to be minimized. In recent years, this option has
received much attention since it requires only small modification of the basic economic dispatch to
include emissions [5, 6].Several methods have been used to represent emission levels.
A summary of environmental/economic dispatch algorithms dating back to 1970 using
conventional optimization methods has been provided in [7]. In [4], the environmentally
constrained economic dispatch problem is solved using the Hopfield NN method in which the
energy function of the Hopfield Neural Network contains both the objective function, and equality
and inequality constraints. Also the emission is inserted as a constraint and the problem was solved
using Neural Network in [8]. Abido [1, 9–11] tried to find the best compromise between the
conflicting targets of minimum cost and minimum emission by means of suitable Pareto based
multi-objective procedures. In other research direction, the emission/economic dispatch problem
was converted to a single objective problem by linear combination of different objectives as a
weighted sum [12]. A new evolutionary computation technique, called Differential Evolution (DE)
algorithm, has been proposed and introduced recently [13–16]. The algorithm is inspired by
biological and sociological motivations and can take care of optimality on rough, discontinuous
and multi-modal surfaces. The DE has three main advantages: it can find near optimal solution
regardless the initial parameter values, its convergence is fast and it uses few number of control
parameters. In addition, DE is simple in coding and easy to use. It can handle integer and discrete
optimization problems [13–16].
2. FORMULATION OF EMISSION CONSTRAINED ECONOMIC LOAD DISPATCH
PROBLEM
2.1 Objective Function
The main objective of ECELD problem aims to minimize operating fuel cost while satisfying all
system equality and inequality constraints. The solution of ECELD problem attempts to reduce the
production of atmospheric emissions such as sulfur oxides SOx and nitrogen oxides NOx, caused
by the operation of fossil-fueled thermal generation. Such reduction is achieved by including
emissions as a constraint in the objective of the overall dispatching problem.
The objective function of ECELD problem is expressed as overall cost function .The overall cost
function is minimizing the total operating cost while keeping the emission from the generating unit
under its maximum limit.
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Nandan Kumar Navin
jg = p p oq,D r"q,D s + µ
Du qu
× ¥q,D ,"q,D ),1)
Where jg = the total generating cost over the whole dispatch period
T= the number of intervals in the scheduled horizon
µ= the emission penalty factor
N= the number of generating units
oq,D r"q,D s = The fuel cost in terms of its real power output "q,D at time t
¥q,D r"q,D s = The emission cost in terms of its real power output "q,D at time t
The fuel cost function of the v Dw thermal generating unit is expressed as the quadratic function as:
+ yq × "q,D
oq,D r"q,D s = xq × "q,D
+ zq ,2)
Where xq , yq , x{(zq = fuel cost coefficients
"q,D = The power output of the v Dw unit in MW
The emission cost function of the v Dw thermal generating unit is expressed as the quadratic function
as:
¥q,D r"q,D s = ¦q × "q,D
+ §q × "q,D
+ ¨q ,3)
Where ¦q , §q , x{(¨q = emission cost coefficients
"q,D = The power output of the v Dw unit in MW
2.2 System Constraints:There are two types of constraints in ECELD Problem.
1) Equality constraints
2) Inequality constraints
2.2.1 Equality Constraints
(1) Power Balance Constraint
The sum of the unit generation output at each hour must satisfy the system load demand
requirement of the corresponding hour as follows:
p "q,D
qu
= "6,D ,4)
Where "6,D = Total power demand at hour t
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Emission Constrained Economic Load Dispatch Problem Using Differential Evolution Algorithm
"q,D = Power generated by unit i at hour t
2.2.2 Inequality Constraints
(1) Emission Constraints
The emission of the generating unit is under its maximum limit.
p p ¥q
Du qu
≤ ¥q€ ,5)
(2) Generations Limit Constraints
The power produced by each unit must be within certain limits, as indicated below:
"qq} ≤ "q,D ≤ "q€ ,6)"qq} , "q€ =The
generations are limits of unit i respectively.
minimum
and
maximum
3. DIFFERENTIAL EVOLUTION ALGORITHM
3.1 Overview of Differential Evolution (DE)
Differential Evolution (DE) is an evolutionary algorithm based on the populations of possible
candidate solutions with three operators: mutation, crossover and selection. In DE candidate
solutions are identified by vectors and set of vectors generate the population. The basic notion is to
form new vector by means of the weighted difference between the two population vectors. These
three vectors are chosen randomly. Then the fitness of new vector is checked. If the fitness of the
last vector is better than the previous two, then the exchange takes place.
The performance of DE is heavily dependent on the setting of control parameters. Proper selection
of control parameters is very important for the success of the algorithm. An optimal setting of
control parameters of DE depends on the specific problem under consideration.
3.1.1 Initialization
The basic step in DE optimization is to create an initial population of candidate solutions by
assigning random values to each decision parameter of each individual of the population. A
population P consisting of n individuals is constructed in a random manner such that the value
lies within the feasible bounds "‚q} and "‚€ of the decision variable, according to the following
rule:
"q,‚ = "‚q} + ƒx{( × r"‚€ − "‚q} s,7)
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Nandan Kumar Navin
Where i= 1, 2,..…, n Denotes the individual’s population index
j=1, 2,….,D Signifies the D-dimensional search space position
"‚q} =Lower bound of the decision variable
"‚€ =Upper bound of the decision variable
ƒx{(= A uniformly distributed random number varies between 0 to 1
3.1.2 Mutation
Next generation offspring are introduced into the population through the mutation process.
Mutation is performed by choosing three individuals from the population "}… in a random
manner.
Let "Y , "Y† , "Y‡ represent three random individuals such that ƒx ≠ ƒy ≠ ƒz ≠ v upon which
mutation is performed during the ‰ Dw generation as:
eq
,Š)
,Š)
,Š)
,Š)
= "Y + ‹Œ × "Y† − "Y‡ Ž,8)
3.1.3 Crossover
New offspring members are reproduced through the crossover operation based on binomial
Š
distribution. The members of the current population (target vector) "q,‚
and the members of the
,Š)
mutated individual eq,‚
,Š)
are subjected to crossover operation thus producing a trial vector q,‚
according to following rule:
Š
q,‚
=
Š
eq,‚
, v‹ƒx{(#0,1' ≤ gY
– ,9)
‘
Š
"q,‚ ,’&ℎ”ƒ•v/”
Where gY is the crossover constant that controls the diversity of the population and prevents the
algorithm from getting trapped into the local optima. The crossover constant must be in the range
of [0, 1].
3.1.4 Selection
Selection procedure is performed with the trial vector and the target vector to choose the best set of
individuals for the next generation. In this proposed approach, only one population set is
maintained and hence the best individuals replace the target individuals in the current population.
The objective values of the trial vector and the target vector are evaluated and compared. If the trial
vector has better value, the target vector is replaced with the trial vector as per the following rule:
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Emission Constrained Economic Load Dispatch Problem Using Differential Evolution Algorithm
"qŠ = ‘
qŠ , v‹‹rqŠ s ≤ ‹r"qŠ s
,10)–
"qŠ ,’&ℎ”ƒ•v/”
4. DIFFERENTIAL EVOLUTION ALGORITHM FOR ECELD PROBLEM
The detailed implementation of the DE algorithm to find a solution for the ECELD problem is
given below.
Step 1: Read data, viz. Cost coefficient ( xq , yq , zq ), population size (L), boundary constraints of
optimization variables (NG), mutation factor (FM), crossover rate (CR), and the stopping criterion
of maximum number of iterations (m$€ ),"qq} , "q€ .
Step 2: Randomly generate an initial population of each individuals using Eq. (7).
Step 3: Calculate the fitness of each individuals of initial population (target vector matrix) using
Eq. (11), which is the total production cost of all units of the system.
=mno = p p oq,D r"q,D s + ª × šp p "q,D − "6,D › + μ × ¥q,D r"q,D s,11)
Du qu
Du qu
Step 4: Select the maximum fitness of the initial population, i.e., the minimum cost of production
†7D
of the initial population and set as cost is o‚†7D and"‚,q,D
= "‚,q,D .
Step 5: Set iteration IT=1
Step 6: Perform mutation operation on initial population using Eq. (8).
Step 7: Calculate the fitness of each individuals of donor vector matrix using Eq. (11).
Step 8: Perform crossover operation on initial population using Eq. (9)
Step 9: Calculate the fitness of each individuals of trial vector matrix using Eq. (11).
Step 10: If fitness of the trial vector matrix is greater than or equal to the fitness of the target vector
matrix, then the target vector matrix is replaced by the trial vector matrix using Eq. (10), otherwise,
the target vector matrix remains the same.
Step 11: Calculate the new objective value by Eq. (11) and set as cost iso‚}… .
†7D
}…
Step 12: If (o‚}… < o‚†7D ) THEN set (o‚†7D = o‚}… ) and ("‚,q,D
= "‚,q,D
)
Step 13: If the iteration is less than the maximum iteration m$ < m$€, m$ = m$ + 1 and return to
step 5
†7D
give the optimum output.
Step 14: STOP and o‚†7D &"‚,q,D
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Nandan Kumar Navin
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Emission Constrained Economic Load Dispatch Problem Using Differential Evolution Algorithm
Test System: The cost coefficients, generation limits, load demand of a ten unit system is taken
from [12].
Input data for ten generating units
Unit 1
Unit 2
Unit 3
Unit 4
Unit 5
Unit 6
Unit 7
Unit 8
Unit 9
Unit 10
455
130
130
162
80
85
55
55
55
150
20
20
25
20
25
10
10
10
a($/MW h) 0.00048 0.00031 0.0021
0.0021
0.00398 0.00712 0.00079 0.00413 0.00222 0.00173
b($/MW h) 16.19
17.26
16.60
16.50
19.70
22.26
27.74
25.92
27.27
27.79
c($/h)
1000
970
700
680
450
370
480
660
665
670
α($/h)
0.04702 0.04652 0.04652 0.04652 0.00420 0.00420 0.00680 0.00680 0.00460 0.00460
Ÿ ¡¢ (MW) 455
Ÿ £¤ (MW) 150
2
β($/MW h) -3.9864 -3.9524 -3.9023 -3.9023 0.3277 0.3277 0.5455
0.5455
0.5112 0.5112
γ($/MW2h) 360.0012 350.0056 330.0056 330.0056 13.8593 13.8593 40.2699 40.2699 42.8955 42.8955
OPTIMAL SCHEDULING OF THE GENERATING UNIT
Test case
Power Generations of Units(MW)
Power Operati Emission
Demand ng
generated
Unit 1 Unit 2 Unit 3 Unit 4 Unit 5 Unit 6 Unit 7 Unit 8
(MW) cost($) (kg)
Case-1
Economic
scheduling
1000
24759
9597
440.59 150
Case-2
Emission
scheduling
1000
25965
4574
Case-3
Emission
constrained
economic
scheduling
1000
25007
7236
61.92 125.97 74.10
Unit 9
Unit
10
34.01
25
40.55
32.85
14.98
250.55 174.33 82.53 121.40 150.23
60.53
32.12
38.20
47.28
42.78
353.56 183.33 86.53 130
25
10.74
27.32
27.32
39.33
20
5. CONCLUSION
In this paper, the emission constrained economic load dispatch problem (ECELD) is solved using a
robust DE algorithm. The maximum penalty factor method is used to incorporate the emission cost.
The performance of DE was tested on a system of ten generating units. The results of economic
scheduling, emission scheduling and emission constrained economic scheduling are compared. The
results show that the price of emission allowances has a major effect on the final solution of the
emission constrained economic load dispatch problem (ECELD).
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Nandan Kumar Navin
REFERENCES
[1] M.A. Abido, Environmental/economic power dispatch using multi objective evolutionary algorithms,
IEEE Transactions on Power Systems 18 (November (4)) (2003).
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power dispatch, in: Universities Power Engineering Conference, UPEC 2004, 39th International,
10/2004, vol. 1, pp. 422 426.
[3] B.H. Chowdhury, S. Rahman, A review of recent advances in economic dispatch, IEEE Transactions on
Power Systems 5 (November (4)) (1990) 1248–1259.
ınoz, H. Altun, U. Hasan, Environmentally constrained economic dispatch via neural
[4] T. Yalc
networks, in: IEEE AFRICON, 6th AFRICON Conference in Africa, George, South Africa, October,
2002, pp. 923–928.
[5] A.A. El-Keib, H. Ma, J.L. Hart, Economic dispatch in view of the clean air act of 1990, IEEE
Transactions on Power Systems 9 (May) (1994) 972–978.
[6] J.S. Helsin, B.F. Hobbs, A multi objective production costing model for analyzing emission dispatching
and fuel switching, IEEE Transactions on Power Systems 4 (August) (1989) 836–842.
[7] J.H. Talaq, F. El-Hawary, M.E. El-Hawary, A summary of environmental/ economic dispatch
algorithms, IEEE Transactions on Power Systems 9 (August) (1994) 1508–1516.
[8] T.S.R. Raja, N.S. Marimuth, N.A. Sing, A novel neural network for economic load dispatch with
environmental constraints, International Journal of Electrical and Power Engineering 1 (1) (2007) 7–12.
[9] M.A. Abido, A niched Pareto genetic algorithm for multi-objective environmental/ economic dispatch,
Electrical Power and Energy Systems 25 (2003) 97–105.
[10] M.A. Abido, Multi objective evolutionary algorithms for electric power dispatch problem, IEEE
Transactions on Evolutionary Computation 10 (June (3)) (2006).
[11] M.A. Abido, A novel multi objective evolutionary algorithm for environmental/economic power
dispatch, Electric Power Systems Research 65 (2003) 71–81.
[12] J.S. Dhillon, S.C. Parti, D.P. Kothari, Stochastic economic emission load dispatch, Electric Power
Systems Research 26 (1993) 186–197.
[13] R. Storn, K. Price, Differential Evolution – A Simple and Efficient Adaptive Scheme for Global
Optimization over Continuous Spaces, Technical Report TR- 95-012, ICSI, 1995.
[14] S. Das, A. Abraham, A. Konar, Particle Swarm Optimization and Differential Evolution Algorithms:
Technical Analysis, Applications and Hybridization Perspectives, (accessed July22, 2009).
[15] D. Karaboga, S. Okdem, A simple and global optimization algorithm for engineering problems:
differential evolution algorithm, Turkish Journal of Electrical Engineering 12 (1) TUBI˙TAK (2004).
[16] R. Storn, K. Price, Differential evolution, a simple and efficient heuristic strategy for global optimization
over continuous spaces, Journal of Global Optimization 11 (1997) 341–359.
,
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Pumped Storage Concept and its Potential Application in
Nepalese Hydropower Context – A Case Study of Chilime
Hydropower Plant Rasuwa, Nepal
Niroj Maharjan1, Sailesh Chitrakar2, Nikhel Gurung3, Ravi Koirala4
1,2,3,4
Turbine Testing Lab, Department of Mechanical Engineering, School of Engineering, Kathmandu
University, Dhulikhel, Nepal
ABSTRACT
Due to fluctuation in energy production from hydropower plants, the existing plants in Nepal
cannot meet the current demand of energy resulting in the power cut during peak hours.
Therefore, there is a dire need for an energy storage unit that can meet the surplus demand of
energy during peak hours. A pumped storage plants can be used to store electrical energy during
periods of low demand and consume the energy during peak energy demand periods. Such
plants generally make use of Reversible Pump Turbines (RPTs). The following paper discusses
the potential application of pumped storage system and RPT in context of existing and new
hydropower plants in Nepal by studying the case of Chilime Hydropower Plant in Rasuwa,
Nepal. The study revealed that the proper application of this technology could certainly aid in
minimizing the energy crisis currently faced by Nepal.
Keywords: Hydropower, Reversible Pump Turbine (RPT), Pumped storage plant, Energy
demand, Chilime Hydropower Plant
1. INTRODUCTION
Nepal, having a tremendous potential of water resources, the development of Hydropower plants
seems to be the most viable and promising solution to meet the current energy crisis problem [1].
About 762 MW of electricity is generated from existing large and small hydropower plants in
Nepal which is not enough to meet the peak demand of electricity (about 1094 MW) for its current
consumers, let alone electrifying other areas [2, 3]. Furthermore, Nepal Electricity Authority
(NEA) forecasts that a total required energy of 5859.60 GWh and a peak demand of 1271.70 MW
for the year 2013/14, which is certain to aggravate the problem of power cut often popularly known
as load shedding making it an inevitable part of Nepalese society [4]. Thus, this situation forces us
to focus not only on developing new plants for more generation capability, but also on developing
the storage technologies to store energy for dry seasons [5]. The pumped storage plant is a wellestablished technology capable of meeting both criteria [6]. By using this technology in existing
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Niroj Maharjan, Sailesh Chitrakar, Nikhel Gurung, Ravi Koirala
and new hydropower plants, the peak demand of power can be satisfied by returning water back to
the reservoir through pump turbine during off peak hours [7].
A pumped storage hydro-plants are commonly used for load balancing in power systems. When
power demand is at its peak, water is released through the turbines to generate electric power. As
the demand decreases, a large amount of electric power is available on the grid. This surplus power
is used to pump water to a high level, natural or artificial reservoir, in order to utilize the stored
energy at periods when it is most needed. With its ability to pump back water from the lower into
the higher reservoir, the plant acts like a giant rechargeable battery, using readily available power
to provide reliable and flexible power to cover peak demand [8]. Instead of using separate turbine
and pump, most pumped storage system use one pump/turbine unit i.e. Reversible Pump Turbine
(RPT), a shift able unit selectively displaceable to achieve alternatively, either an energy generation
or an energy accumulation mode [9]. Such a machine is possible because Francis turbine is just a
reverse of a centrifugal pump. The efficiency of this system is typically between 70% and 85%,
making it one of the more efficient methods for storing energy [10]. The same power lines,
connected to the power transmission grid, provides the electric power required to pump back water,
and transport the power generated by the plant when it is operating in turbine mode.
2. APPLICATION PROSPECT AND APPROACH
Since the energy production from hydropower plants in Nepal are not always the same, there is an
immense need of energy storage units for constant supply [11]. Pumped storage unit is a mature
technology and a very suitable method for Nepal. Since Nepal does not have a concrete tariff plans
for electricity consumption and the local electricity demand is always high [12], the idea however
is different. Hydropower plants in Nepal during monsoon have an excess amount of water supply
while in dry season it is difficult to meet the minimum supply of water required to run all units.
But, there are several sites in Nepal with two rivers close enough with different head. RPT units
can act as a link between such rivers.
As shown in Fig. 1, water can be pumped from level H1 to the upper reservoir during dry season to
meet the need to run all the turbine of the main unit. Due to the head difference between H1 and
H3, relatively less amount of energy is used to pump a fixed amount of water and a higher amount
of energy is generated from the same amount of water using the main turbine unit. While in
monsoon when the water supply is more, the excess amount of water is sent through the RPT
generating an excess amount of electricity. The technology is thus feasible for country like Nepal
where there are a huge number of perennial rivers that flow very close to each other and have
different heads.
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Pumped Storage Concept and its Potential Application in Nepalese Hydropower Context – A Case Study of
Chilime Hydropower Plant Rasuwa, Nepal
Figure 1: Schematic pumped storage plant
In Fig. 1,
H1 = Head at lower reservoir of RPT
H3 = Head at tailrace level of main unit
ηrpt/p = efficiency of RPT in pump mode
ρ = density of water
Q = water discharge through main unit
H2 = Head at upper reservoir level
ηt = efficiency of main unit
ηrpt/t = efficiency of RPT in turbine mode
g = acceleration due to gravity
∆Q = additional water discharge when RPT is
used
Mathematically,
1. When pump turbine is not used
Total power = ηt.ρ.g.Q.(H3-H2) (1)
2. When pump turbine is used
During dry season,
Total power = ηt.ρ.g.Q.(H3-H2) + ηt.ρ.g.∆Q.(H3-H2) – ρ.g.∆Q.(H2-H1+losses)/ηrpt/p
During wet season,
Total power = ηt.ρ.g.Q.(H3-H2) + ηt.ρ.g.∆Q.(H3-H2) + ηrpt/t .ρ.g.∆Q.(H2-H1-losses)
(2)
(3)
3. SITE SELECTION
The site was selected under the criteria of potential capacity, location from demand centers, water
availability, head conditions, accessibility and cost. After analyzing the available secondary data
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Niroj Maharjan, Sailesh Chitrakar, Nikhel Gurung, Ravi Koirala
and obtaining new data as per the objective, Chilime Hydropower in Rasuwa was taken as
reference site and the possibility of RPT installation in this site was studied.
Location. The proposed site is located at Syaphrubensi, Briddhim and Goljun VDC, Rasuwa
District of Bagmati Zone. The geographical location of the project area is between latitude 28ῆ 09’
20’’ N to 28ῆ 11’ 00’’ N and longitude 85ῆ 19’ 20’’ E to 85ῆ 20’ 45’’ E. The project area is
approximately 170 km northwest of Kathmandu.
Description. The scheme consists of an upper reservoir, an underground power house complex
with access tunnels and associated waterways, 2 Pelton turbines (each rated 11.25 MW) coupled
directly with generator-motors and ancillary works that include building works, roads, transmission
lines and temporary and permanent infrastructure. The gross head and the discharge for the unit is
351.5 m and 8.2 m3/s respectively.
Geology. The area has steep slope and no prominent lineament was observed during the field visit.
The foothills are covered by colluvial soil. The ridges are barren rocky terrains. Gneiss and
quartzite are two main rock types found at the site.
Mean Monthly Discharge
Design Discharge
River Discharge (m3/s)
60.00
50.00
40.00
30.00
20.00
10.00
0.00
Month
Figure 1: The Chilime River Discharge Graph
Hydrology. The existing plant utilizes the water from the Chilime River, which constitutes one of
the major tributaries of the Trishuli River Basin that drains the central region of Nepal. The
Chilime basin is located in between latitudes 28ῆ 25' and 28ῆ 10' N and longitudes 85ῆ 5' and 85ῆ
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Pumped Storage Concept and its Potential Application in Nepalese Hydropower Context – A Case Study of
Chilime Hydropower Plant Rasuwa, Nepal
20' E. The total catchment area of the river is about 277 km2 and may be divided into two parts.
The upper catchment having an area of about 170 km2 is a mountainous arid valley in the
Himalayan region. The river is known as Sanjen Khola in this upper catchment, which is then
known as Chilime Khola in the lower catchment after having been joined by other tributaries. The
Chilime River joins the Bhotekoshi River downstream and then, the Langtang River at Syafrubesi
and is known as the Bhotekoshi River afterwards.
The yearly discharge graph of the Chilime River is shown in the Fig. 2. As shown in the Fig. 2, the
existing unit runs at full capacity during six months of the year and is operated in part load
condition in the remaining months resulting in low efficiency and low power output. Moreover, the
graph shows that during six months of the year from May to October, the discharge is far more than
is actually utilized.
4. PUMPED STORAGE AND RPT FEASIBILITY
The Chilime River is a run-off river and its discharge is not constant. However, the Bhotekoshi
River that flows nearby the Chilime River is a perennial river with abundant amount of water all
the year round. Therefore, studies were carried out to determine the technical feasibility of using
water from the Bhotekoshi River to supplement the main unit during dry season. With the current
reservoir for main unit taken as the upper reservoir for RPT, the major task of the study was to
determine the location for powerhouse and lower reservoir, where water from the Bhotekoshi is to
be collected.
Figure 3: Aerial view of the site (Source: Google earth)
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Niroj Maharjan, Sailesh Chitrakar, Nikhel Gurung, Ravi Koirala
The survey study revealed that there are two feasible sites where the RPT and the lower reservoir
might be built. The first site is at distance of about 6.2 km downstream the upper reservoir with the
gross head of 257 m (case 1). Similarly, the second site is about 5.4 km from the upper reservoir
with the total head is 126 m (case 2). Calculations were performed to estimate the amount of net
energy that will be produced by installing the RPT at these sites. In order to determine which site is
the best, the energy produced by installing RPT at these sites were compared with the energy
produced originally without using RPT. The monthly energy production distribution is shown in
the Fig. 4.
5. DATA AND ASSUMPTIONS:
ηrpt/p = 85%,
ηrpt/t = 90%
ηt = 80%,
Net Head for main unit = 337.5 m
Energy produced/consumed by the unit = power [MW] * no. of days in a month * 24 [MWh]
(4)
For case 1,
For case 2,
Head during pumping = 260 m
Head during pumping = 140 m
Head during turbine mode = 254 m
Head during turbine mode = 123 m
Table 1: Monthly Energy calculations
For case 1
For case 2
M
o
n
t
h
River
Discha
rge
[m3/s]
Energy
Output
without
using RPT
[MWh]
Main unit
output with
RPT
[MWh]
Pumping
Energy
[MWh]
1
3.15
6207.49
14090.02
2
2.73
4859.20
11978.90
3
3.42
6739.56
14622.10
8930.10
4
5.82
11099.11
15637.92
5142.01
5
10.82
16159.19
16159.19
0.00
4371.39
20530.58
0.00
2116.85
18276.04
6
23.40
15637.92
15637.92
0.00
9687.89
25325.81
0.00
4691.38
20329.30
7
43.07
16159.19
16159.19
0.00
10010.81
26170.00
0.00
4847.76
21006.95
8
48.03
16159.19
16159.19
0.00
10010.81
26170.00
0.00
4847.76
21006.95
9
33.97
15637.92
15637.92
0.00
9687.89
25325.81
0.00
4691.38
20329.30
10
14.92
16159.19
16159.19
0.00
10010.81
26170.00
0.00
4847.76
21006.95
11
7.00
13349.45
15637.92
2592.61
13045.31
1396.02
14241.90
12
4.28
8434.31
16159.19
8751.50
7407.69
4712.35
11446.84
146601.73
184038.67
42412.22
195406.05
22837.35
187244.20
Total
Output
Energy
from RPT
[MWh]
Output
Energy
from
RPT
[MWh]
Net Energy
Output
[MWh]
Pumping
Energy
[MWh]
8930.10
5159.92
4808.52
9281.51
8065.90
3913.01
4343.18
7635.73
5691.99
4808.52
9813.58
10495.92
2768.77
12869.15
53779.60
Net Energy
Output
[MWh]
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Pumped Storage Concept and its Potential Application in Nepalese Hydropower Context – A Case Study of
Chilime Hydropower Plant Rasuwa, Nepal
without RPT
with RPT at 257 m Head
with RPT at 126 m Head
Energy production [ MWh]
30,000.00
25,000.00
20,000.00
15,000.00
10,000.00
5,000.00
0.00
1
2
3
4
5
6
7
8
9
10
11
12
Month
Figure 4: Energy production graph
6. ANALYSIS
The graph shows three curves indicating
a) Monthly energy production in present case (without RPT)
b) Energy produced when RPT installed at gross head of 257 m (case 1)
c) Energy produced when RPT installed at gross head of 126 m (case 2)
The graph shows that during wet season, more energy is produced since the RPT works as turbine
in this case. But, it is during dry season when the RPT is needed most. Note that, if all the units
were ideal (i.e. no losses in the system), then the net energy produced will be the function of head
difference only. Thus, in such case, installing the RPT at any position with less head difference
than the main unit would result in feasible system. However, in real case, various losses occur in
the system, which may result in net decrease in production of energy when RPT is used as evident
in case 1. From Table 1 and Fig. 4, the net energy production for case 1 during dry season is less
than the energy produced in current case. As discussed before, this is because the pumping energy
required for pumping the water from lower reservoir to upper reservoir is more than the net energy
generated by running the same water through the main turbine unit due to various losses in the
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Niroj Maharjan, Sailesh Chitrakar, Nikhel Gurung, Ravi Koirala
system. Hence, the result is a net consumption in energy by using RPT in pump mode resulting low
energy production in total.
Conversely, in case 2, the energy produced during wet season is comparatively lower than in case 1
since the total head is lesser than case 1. But, the lower head means less pumping energy required
for pumping water during dry season. As a result, the net amount of energy produced in dry season
is more than the energy that was originally produced proving the viability of the project.
7. BENEFITS
The concept of RPT and pump storage system is new for Nepal. Yet, it can prove to be a promising
solution to the major problem of water shortage in hydropower plants in dry season. The
installation of RPTs as a supplement to the major hydropower plants can aid in utilizing the water
from nearby river to operate the main unit to run at best efficiency point all the year round. It does
not affect the natural load curve but its double face characteristics (load or generator) helps to
avoid the unnecessary peak plant construction and also the better utilization of the existing base
power plants. This will not only help conserve energy and money, but it will also help to meet the
high electricity demand during dry season. Further, the running of main unit at constant discharge
condition all the year round increases the efficiency and life of the main unit. Apart from this, the
use of single machine acting as both pump as well as turbine saves the cost of one full machine and
eliminating elaborate hydraulic connections, piping and couplings.
8. CONCLUSION
Most hydropower plants in Nepal are run-off type with no storage potential, which cannot meet the
current peak demand of electricity leading to omnipotent power curtailing problem. Pumped
Storage Hydroelectricity improves the efficiency of power plants by allowing them to run at
maximum efficiency without wasting energy. They can also serve the electricity storage needs
required in order to provide a consistent and reliable grid, which can match the demand.
The case study of Chilime Hydropower Plant suggests that out of the two possible alternatives for
pump turbine installation, the one with gross head of 126 m is more suitable than the one with 257
m head since the net energy production is more in the former than the latter. The study also
strengthens the concept of using pump storage system as auxiliary unit along with the existing main
unit to make the maximum utilization of available water resources. Although the application
philosophy is somewhat unorthodox, the idea certainly has a potential to increase the effectiveness
of hydro power plants and meets the short term as well as long term energy needs of Nepal and
hence, further research in the topic is highly recommended.
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Pumped Storage Concept and its Potential Application in Nepalese Hydropower Context – A Case Study of
Chilime Hydropower Plant Rasuwa, Nepal
REFERENCES
[1] Bhattari B, Budha B. On hydro-power development: Prospects and challenges. in The Himalayan
Times, ed. Nepal, 2012.
[2] Electricity Generation Power Plants and Projects. A Year in Review-Fiscal Year 2012/13, ed. Nepal,
2013: 111.
[3] Total Energy Available and Peak Demand. A Year in Review-Fiscal Year 2012/13, ed. Nepal, 2013:
105.
[4] Load Forecast. A Year in Review-Fiscal Year 2012/13, ed. Nepal, 2013: 109.
[5] Kádár D P. Pumped Storage Hydro Plant model for educational purposes. Hungary: Dept. of Power
Systems, Budapest Tech: 5.
[6] Steffen B. Prospects for pumped‐hydro storage in Germany. University of Duisburg‐Essen (Campus
Essen), Germany 2011.
[7] Hydroelectric pumped storage technology: international experience. Task Committee on Pumped
Storage, Committee on Hydropower of the Energy Division of the American Society of Civil Engineers,
New York: American Society of Civil Engineers.
[8] Ciocan G, Tellor O, Czerwinski F. Variable Speed Pump Turbines Technology. U.P.B. Science Bulletin,
vol. 74, 2012: 10.
[9] Atencio F. Reversible pump-turbine. US Patent US 4275989 A; Jun 30, 1981.
[10] Lal J. Recent Trends in the Development of Water Turbines and Modern Hydro Power Plants. Hydraulic
Machines. Metropolitan Book Co. Pvt. Ltd., 2009: 285-292.
[11] Nepal Hydropower Overview. Information on http://www.hidcl.org.np/nepal-hydropower.php
[12] Gautam S. Future of Nepal's Electricity: long term policy suggestions. in EngeryForNepal vol. 2014.
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Super Capacitor Power System for
Sounding Rocket Payloads
P.P.Antony, S. Saju, R.G.Hari kumar Warrier, B.Manoj Kumar
Vikram Sarabhai Space Centre, Indian Space Research Organisation
Thiruvananthapuram, India 695022
ABSTRACT
Sounding rockets are a means of accessing middle atmosphere region for doing in-situ
measurements of wind velocity, density measurements of electron, ion & photon, neutral wind
velocity etc. RH200 chaff payload sounding rocket is intended to measure the middle atmosphere
wind velocity about an altitude of 60-75 km using copper chaff cloud. The payload contains a
sequencing timer, batteries & its associated pyro devices. The sounding rocket batteries are made
up of high-energy silver-zinc(Ag-zn) cells capable to deliver high discharge pulse currents for
pyro devices as well as the timer working voltage for a flight duration of about 120 seconds.
These batteries require definite preparation time since it involves electrolyte filling, soaking and
formation cycles, charging/discharging activation and its wet life is only six months. Sounding
rocket launch schedules are highly volatile in nature and this paper gives a solution to above
problem by using super capacitors instead of silver-zinc batteries. Super capacitor
configurations, various test methods, qualification cycle and launch safety aspects adopted to
induct these devices for aerospace use are described. Maxwell make ultra-capacitors were
successfully flight tested in ISRO RH200 two-stage sounding rocket launched from Thumba
equatorial rocket launching station (TERLS) and the test results are also included in this paper.
Key words: super capacitor, Pyro devices, telemetry, squib, countdown, launch, sounding rocket,
sustainer, chaff ejection
1. INTRODUCTION
Super capacitors are electrochemical devices which performs mid-way between batteries and
conventional capacitors. As compared to batteries these devices can store only limited amount of
charge but its power density is very high hence it can deliver high amplitude current pulses of
multiple times.
High charge retention, ultra low internal resistance, high capacitance values are the other important
features of super capacitors. Since the individual device voltage is only 2.5V, super capacitors are
to be connected in series to get the required supply voltage. Super capacitor cell balancing during
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Super Capacitor Power System for Sounding Rocket Payloads
charging and charge retention schemes to be taken into consideration while dealing with super
capacitors. Generally super capacitors are connected in parallel to batteries to improve their power
delivery capacity for handling transient peak pulse loads.
RH200 sounding rocket is a two stage vehicle uses solid propellant with an overall length of 1180
mm and a lift mass of 120kg. First (Booster) stage is ignited from ground and Second (Sustainer)
stage as well as chaff ejection pyro initiators are commanded by the onboard sequencing timer.
The avionics system power requirements of sounding rocket payloads are generally very small (less
than 250 joules) however high energy batteries are used presently for meeting the high discharge
current pulse loads of pyro devices. Most of the charged battery capacity wasted in battery itself
even after completing the flight duration. Super capacitor power source design gives more focus on
total energy delivery with adequate margin hence the size and weight of power source can be
reduced.
As the super capacitor research progresses and in future dynamically variable capacitors also may
be available to maintain a constant voltage output which further reduces the size and volume of
capacitors.
2. PAYLOAD AVIONICS CONFIGURATION
Payload avionics have two functions; one system consists of super capacitor interface unit,
sequencing timer & pyro devices in functional chain for the rocketry and the other system is to
monitor their flight performance using Pulse code modulation (PCM) telemetry and S-band
transmitter operating on Ag-Zn battery as shown in Figure 1. .
The electrical system have features like power changeover control relays, battery charging and
monitoring circuits, relay pole voltage monitoring circuit etc. A 10 channel PCM encoder with
analog to digital converter at a data rate of 200 kbps, 0.5W S-band transmitter forms the onboard
telemetry chain. Super capacitor voltage and current values are transmitted during flight.
Super capacitors are configured in two bank sections where the first bank with five capacitors
connected in series for the working of onboard timer working supply and the chaff ejection release
pyro and the second bank section with two capacitors connected in series for the sustainer ignition
pyro initiation. AD8202 instrumentation buffer amplifier and non-invasive hall-effect current
sensor is used for voltage and current monitoring circuits respectively. For electrostatic discharge
protection bleeder resistors are provided at battery sources and pyro initiator circuits.
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P.P.Antony, S. Saju, R.G.Hari kumar Warrier, B.Manoj Kumar
Fig.1. Payload avionics configuration
3. SUPER CAPACITOR ESTIMATION TECHNIQUES
Super capacitors are charged from ground power supplies and its discharge starts from rocket takeoff. The energy storage capacitor power source should have sufficient capacitance value to
maintain the voltage in the prescribed range for a specified amount of time. The parameters to
determine the capacitor value are maximum to minimum operating range of working voltage,
current drawn and discharge duration. In this case the capacitance estimation is given below.
Working voltage range (Vw) = 10V to 7.5V
Estimated current (IL) = 250mA
Discharge duration (td) = 120 Seconds
Energy delivery (∆E) = Vw * IL * td
(1)
Eq. (1) gives a maximum energy delivery of 300 Watt-seconds or joules. From this equation the
capacitor value can be estimated by eq(2).
∆E = ½ C(Vi2 – Vf2)
(2)
Where C - Capacitor value, Vi – Initial discharge voltage, Vf – Final discharge voltage.
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Super Capacitor Power System for Sounding Rocket Payloads
Figure 2. Super capacitor stack configuration
Figure 3. Photograph of super capacitor unit
From eq(2) the capacitor value estimated as 13.71 Farads. Absolute maximum rating of super
capacitors is 2.5V and to ensure necessary de-rating it is charged up to 2V only. Hence 5 capacitors
are to be connected in series to get a working voltage of 10V. Individual capacitor value should be
68.55 Farads (13.71 * 5). 140F super capacitor from Maxwell is selected which is above the
estimated value. The energy requirement for pyro suib firing is very low when compared to timer
working and only the required voltage and current to be ensured for an action time of less than 10
milli-seconds. Super capacitor stack configuration is shown in figure 2. where the two capacitors
connected in series (4V/5A) for giving the sustainer rocket ignition. Super capacitor interface unit
photograph is shown in figure.3.
4. QUALIFICATION CYCLE
Super capacitors have to be qualified and further undergo a qualification cycle as given figure 4
before using it in sounding rockets or any other aerospace systems.
Figure 4. Qualification cycle
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P.P.Antony, S. Saju, R.G.Hari kumar Warrier, B.Manoj Kumar
A. Initial Standard room condition (SRC) tests
During SRC tests capacitor parameters like capacitance value, equivalent series resistance (ESR),
and leakage current are to be measured. After SRC tests unit under test should undergo
environmental tests as per the flow chart given in figure 4 these parameters are verified during all
the tests and values should be within the specified tolerances limit otherwise the unit would be
rejected. Test setup photograph is shown in Figure 5. The test setup has power supplies and high
sampling data acquisition system for assessing capacitor parameters.
Figure 5. Photograph of capacitor parameter estimation test setup
B. Super capacitor parameter estimation
(i) Capacitance
Applying a constant charging current and measure the voltage across the capacitor where
capacitance as given in eq (3). Time taken from 0V to 2V at constant current is a direct measure of
capacitance value.
C = IC *tc/(Vf -Vi)
(3)
Where C-capacitance, IC - Charging current, tc – Charging time, Vf - Final voltage, Vi - Initial
voltage.
ii) Equivalent series resistance (ESR)
ESR is the measure of voltage drop observed across super capacitor terminals when a constant load
current is delivered as given in eq (4).
ESR = (Vi- Vf)/Id
(4)
Where Vf - Final voltage, Vi - Initial voltage and Id – Discharge load current.
(iii) Leakage current
The leakage current is a measurement of current drawn from the charging source after holding the
device at rated voltage for 72 hours continuous at room temperature. The measured leakage current
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Super Capacitor Power System for Sounding Rocket Payloads
will be influenced by the temperature during the measurement, the voltage at which the device is
measured and the age of the product. Ideally capacitors take infinite time to get fully charged but
the longer the super capacitors held on charge the lower the leakage current of the device. This is
due to the extremely large surface area of the electrode the time constant of the last 0.5% of the
electrode area is extremely long due to the pore size and geometry.
C. Environmental testing for qualification
During environmental testing various test conditions are excised on super capacitor unit to ensure
the reliability as well as the design margins. The test conditions are derived from the environmental
test levels for sounding rockets. Flight acceptance level is lower than that of qualification level.
5. ROCKET ASSEMBLY & TESTING
The qualified unit is assembled in the rocket payload and an integrated testing have been carried
out before the actual flight. During this testing super capacitor discharge voltage, load current,
pulse loads of pyro devices have to be verified through telemetry link. Rocket assembly, testing
and launch operations were carried out as per the flow chart given in figure 6.
Figure 6. Electrical integration Flowchart for RH200 launches
Payload Avionics power system interfaces, signal conditioner gain setting, PCM slot allocation of
measurements, RF radiated checks of transmitters, sequencer timer checks and pyro line testing
with test squibs are carried out during phase-1 electrical testing. Then the subassemblies are
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P.P.Antony, S. Saju, R.G.Hari kumar Warrier, B.Manoj Kumar
mechanically integrated and flight acceptance vibration testing is carried out. Flight battery
assembly, payload electrical umbilical interface checks, ground station telemetry interface checks
will be carried out before the payload integration with rocket motor.
Safety interlocks are provided in the pyro line circuit and squibs were also kept safe till last minute
launch operations. During pyro arming squibs were electrically connected to battery circuit and the
squib initiation take place when commanded. Since the squibs are untested explosive devices
redundant circuits are provided. Avionics systems are powered from external power supplies
through umbilical and it will be changed over to internal battery just before the rocket lift-off.
6. RH200 SBT-07 SUPER CAPACITOR EXPERIMENTAL FLIGHT RESULTS
SBT-07 instrumented flight performed as expected and very encouraging results are obtained.
Capacitor discharge plot shows a voltage fall of about 1V only during the timer working. Squib
currents are recorded in the band of recommend firing current. Figure 9 shows the current verses
voltage plot of super capacitor discharge during flight. Flight went up to an altitude of 60km for
chaff release and wind velocity measurement.
Figure 7. Payload avionics elements
Figure 8. RH200 SBT-05 ready for lift-off
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Super Capacitor Power System for Sounding Rocket Payloads
Figure 9. Super capacitor voltage and current plot of RH200 SBT-07
7. CONCLUSION
Presently work is in progress to make more sounding rocket launches with the latest range of super
capacitors. This is very reliable cost-effective solution for sounding rockets. At the same time
various efforts are in progress to induct this technology in avionics power system management
circuits of launch vehicle’s critical elements. Indigenous super capacitor development efforts are
also planned.
8. REFERENCES
[1] Sven G. Bilén and Jesse K. McTernan : " Electrodynamic tethers for energy harvesting and propulsion
on space platforms" AIAA 2010-8844 30 AIAA SPACE 2010 Conference & Exposition August - 2
September 2010, Anaheim, California.
[2] Tatsuo Shimizu and Craig I. Underwood "Power subsystem design for micro-satellites using supercapacitor storage" AIAA 2009-4500 7th International Energy Conversion Engineering Conference 2 - 5
August 2009, Denver, Colorado.
[3] Duran-Gomez J.L., Enjeti. P.N., von Jouanne .A, “An approach to achieve ride-through of an adjustablespeed drive with flyback converter modules powered by super capacitors” IEEE trasactions on industry
applications Vol.38, Issue 2, pp.514-522, 2002.
[4] M.G. James, P.P. Antony, D.R. Gurunath, R.G. Harikumar Warrier : “Super capacitor for RH200
instrumented flight – test plan document “, MVIT-SEIG-BEID-682-12, Issue-1 dated Aug-2012.
[5] Henry Mechado : “Evaluation of Maxwell technology power cache ultra-capacitor” SAIC – JSC/NASA
[6] Michael J. Marcel and John Baker: “Integration of ultra capacitors into the energy management system
of a near space vehicle” 5th International energy conversion engineering conference and
exhibit(IECEC),25-27,june 2007, St.Louis, Missouri.
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Recent Advances in Hydrogen Production
C. Bharadwaj Kumar1, P. Sreedhar2, J. Santoosh3, S. S.Chaitanya.B4,
Y.Satya Prasad5, M. Devika6
Department of Chemical Engineering, Sri.Venkateswara University, Tirupati
Keywords: Hydrogen Production, Catalysis, Dehydrogenation, etc.
1. INTRODUCTION
Hydrogen power has long been heralded as the renewable energy source of the future because of its
cost effectiveness and low environmental impact. Unfortunately, Hydrogen gas (H2) is not readily
found in nature, and if generated by fossil fuels or nuclear power, it is falls outside the sphere
renewable energy. In addition, the present methods by which H2 is produced require separate
energy source to create that fuel. Recently, tremendous strides have been taken in generating H2
from renewable and sustainable sources, without environmental degradation. For these scientists,
finding an efficient and renewable method by which the H2 producing Organism can be supplied
energy has become a priority.
Hydrogen gas (H2) can be used for cooking, water heating, space heating, electricity generation,
welding and cutting, and the synthesis and purification of other Chemical materials. When
hydrogen is made from water and renewable energy resources such as PV, wind, or micro hydro,
we refer to the produced gas as “solar-hydrogen.” Solar-hydrogen is a sustainable carbon-free gas.
It can release heat when burned with air or oxygen, or produce electricity when combined
electrochemically with oxygen in a fuel cell. When solar-hydrogen is made or burned, there is no
carbon monoxide, carbon dioxide “greenhouse gas,” or hydrocarbon pollutants produced.
The first element of the periodic table, which is also the most abundant element in the universe,
may be the panacea to solving world’s energy crisis as well as the environmental and ecological
issues arising from carbonaceous emissions. In this article we introduce hydrogen as a
commercially viable fuel and some emerging technologies that make use of this clean fuel.
There is a large and growing demand for hydrogen in the United States and the rest of the world,
with the bulk of the hydrogen being produced by steam reforming of methane with carbon dioxide
as a byproduct. Hydrogen and electricity are expected to dominate the world energy system in the
long term. As the world transitions to a hydrogen economy, hydrogen will be used increasingly by
the transportation, residential, industrial, and commercial sectors of the energy market. Eventually,
the demand for natural gas may outpace its production. There may also be strong environmental
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Recent Advances in Hydrogen Production
and economic incentives in the future to produce hydrogen without generating carbon dioxide as a
byproduct.
2. WHY HYDROGEN
Hydrogen can be used as a fuel replacing gasoline in the automobiles. This means, the size and
look of automobiles is unlikely to change with the use of hydrogen as fuel. Hydrogen burns clean
inside fuel cells and the only resulting emission is water. Hydrogen is considered the ultimate fuel
of the future as it has beneficial effects on global warming, environment and ecology. There are
cost benefits of using hydrogen as fuel, by reduction in the requirements of pollution control. There
are health’s benefits of using hydrogen as fuel – emissions from hydrocarbon combustion are often
believed to be carcinogenic.
Hydrogen (H2) has long been hailed as the fuel of the future. One of the main utilizations of
hydrogen as a fuel is for fuel cells to generate electricity. At present over 90% of available
hydrogen is produced by catalytic steam reforming and partial oxidation of methane (CH4) as well
as steam reforming of carbon monoxide (CO), CH4 and CO are produced from fossil fuels,
particularly coal and natural gas. These processes are however unsustainable, in addition they
release considerable amounts of carbon dioxide (CO2).
There are further difficulties associated with H2 and these include its storage and transportation. H2
is the least dense of all molecules requiring compression and refrigeration for practical applications;
both are energy intensive processes. These difficulties have motivated the findings of other
processes for H2 production.
Ethanol as an energy carrier is easily transported using the existing fuel infrastructure and
conversion to H2 immediately prior to the use in a fuel cell constitutes a practical and efficient
means of energy production. Furthermore ethanol is produced from biomass with little energy input
and steam reforming alleviates the necessity of the energy intensive distillation in the separation of
water from crude ethanol.
Ethanol steam reforming (ESR) may provide a viable step in the search for efficient sustainable
energy production in a transitional period. In addition the process can produce H2 onboard of
stationary or moving devices thus avoiding compression on refrigeration processes. However, the
technology is still in the research and development stage.
Fuel cells have emerged as one of the most promising technologies for meeting future global
energy needs. The full environmental benefit of generating power from hydrogen fuel cells is
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C. Bharadwaj Kumar, P. Sreedhar, J. Santoosh, S. S.Chaitanya. B, Y.Satya Prasad, M. Devika
achieved when the hydrogen fuel is produced from renewable sources such as solar power and
biomass. Indeed, the production of hydrogen from renewable biomass-derived resources is a major
challenge as global energy generation moves towards a “hydrogen society”. In this presentation, we
show that it is possible to generate hydrogen by catalytic reforming of oxygenated hydrocarbons in
liquid water at temperatures near 500ºK.
These reforming reactions lead to high selectivities for the production of hydrogen over Pt-based
catalysts from oxygenated hydrocarbon reactants having a C: O stoichiometry equal to 1:1. For
example, glucose can be converted to hydrogen and gaseous alkanes over platinum-based catalysts,
with hydrogen selectivities of 50 %. Higher selectivities of hydrogen can be achieved from S
orbital and glycerol, and nearly 100 % selectivity for hydrogen production can be achieved for
aqueous-phase reforming of ethylene glycol and methanol.
This aqueous-phase reforming process (i) generates hydrogen without the need to volatilize water,
which represents a major energy saving compared to conventional, vapor-phase, steam-reforming
processes, (ii) occurs at temperatures where the water-gas shift reaction is favorable, making it
possible to generate hydrogen with low amounts of CO in a single chemical reactor, (iii) utilizes
safe transportable non-flammable feed stocks, (iv) can utilize renewable biomass derived feed
stocks, and (v) takes place at low temperatures which minimize undesirable decomposition
reactions typically encountered when carbohydrates are heated to elevated temperatures.
3. BACKGROUND
The world currently consumes about 45 million metric tons of hydrogen per year, with the United
States consuming about one-fourth of this quantity. To put this in perspective, the hydrogen
consumed in the U.S. per year would generate 50 GW (t)-yr if it were burned. Nearly all of this
hydrogen is consumed by the industrial sector, primarily the chemical and refining industries. With
a growing economy, the demand for hydrogen will increase further, especially if the U.S. and other
countries shift their energy usage toward a hydrogen economy, with hydrogen consumed directly
as an energy commodity by the transportation, residential, and commercial sectors.
With recent advances in fuel cells and hydrogen combustion engines, the framework for a
hydrogen economy is already being established. An important issue that must be addressed is the
source of hydrogen to meet this expected increase in demand. Presently, the bulk of hydrogen is
produced by steam reforming of natural gas (methane). The overall process produces 4 moles of
hydrogen for each mole of methane, with carbon dioxide as a byproduct. Alternatives to natural gas
as a source of hydrogen are needed for the following reasons:
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Recent Advances in Hydrogen Production
(1)
Natural gas consumption is outpacing production in the U.S., which will require importing
significant quantities of natural gas in order to fill the projected shortfalls. This increase in
demand may result in significantly higher prices for natural gas.
(2)
Steam reforming of natural gas is not environmentally friendly because it produces the
carbon dioxide.
4. HYDROGEN GAS
As a Renewable Resource
Generating energy via Hydrogen will be the cost effective and efficient renewable energy source of
the future. Of all the renewable sources, it has the potential to have the lowest environmental
impacts, while producing the most energy. Although Hydrogen is the most abundant element in the
universe (more than 75-90% of all atoms), very little H2 exists in nature. Of course, H2 plays a vital
role in powering the universe through stellar hydrogen fusion, like our Sun.
As a Gas Molecule
H2 is a molecule of the element Hydrogen. Hydrogen is the first element on the periodic table, and
thus, has the lowest molecular weight. A typical H2 molecule consists of a single covalent bond.
Two atoms of Hydrogen combine to form a Hydrogen molecule. The most widely accepted theory
assumes that each atom has one orbit, which overlap when combined. Each Hydrogen atom has one
valence electron to share. Since this bond consists of the sharing of electrons it is called a covalent
bond. Hydrogen is an exception to 8-electron valence shell balance required by all other elements,
except Helium. Therefore, the driving force behind creating a stable H2 molecule is to fill the
valence shell with two electrons.
Hydrogen has a number of properties that make it particularly well suited to use as a tracer gas. It
has a very low viscosity and the background concentration of hydrogen in ambient air is relatively
low. As demand for environmental protection becomes more of a priority, researchers, companies
and government incentives build to look at alternate fuels, and resources as methods of both
reducing our dependency on fossil fuels and improve our environment at the same time. Recently
the president of the United States has expounded on the needs to look at alternative fuels and
directly mentioned hydrogen as one of those fuels whose time has come.
5. COMPOSITION
Hydrogen is the simplest and most common element in the universe. It has the highest energy
content per unit of weight---52,000 British Thermal Unit (BTU) per pound (or 120.7 KJ/gm) of any
known fuel. Moreover, when cooled to a liquid state, this low weight fuel takes up 1/700 as much
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C. Bharadwaj Kumar, P. Sreedhar, J. Santoosh, S. S.Chaitanya. B, Y.Satya Prasad, M. Devika
space as it does in its gaseous state. This is one reason hydrogen is used as fuel for rocket
population, which requires fuel that is low-weight, compact, and has a high energy content.
In a free state and under normal conditions, hydrogen is a colorless, odorless, and tasteless gas. The
basic hydrogen (H2) molecule exits as two atoms bound together by shared electrons. Each atom is
composed of one proton and one orbiting electron. Since hydrogen is about 1/14 as dense as air, it
usually exits in combination with other elements, such as oxygen in water, carbon in methane, and
in trace elements as organic compounds.
Because it is so chemically active, it rarely stands alone as an element. When burned (or combined)
with pure oxygen, the only by products are heat and water. When burned (or combined) with air,
which is about 68% nitrogen, some oxides of nitrogen (Nitrogen Oxides or NOx) are formed. Even
then, burning hydrogen produces less air pollutants relative to fossil fuels.
6.
•
•
•
•
•
•
PROPERTIES
Colorless, odorless, non-toxic gas
Most abundant element in the universe
Smallest molecule of all elements
Low volumetric density
Energy input required for “extraction”
Hydrogen occurs almost exclusively locked in other compounds
7.
•
•
•
•
•
•
•
•
PROPERTIES REGARDING SAFETY
Colorless, odorless, non-toxic gas
Easily flammable
Burns with no visible flame in day light
Flame radiates less than other fuels
Hydrogen burns without creating harmful soot
Hydrogen needs more fuel in the air to detonate
High burning velocity means likely to explode in confined spaces
Low volumetric density (lighter than air) means H2 cloud will rise and disperse quickly.
Methods of Production
Hydrogen production is commonly produced by extraction from hydrocarbon fossil fuels via a
chemical path. Hydrogen may also be extracted from water via biological production in an algae
bioreactor, or using electricity (by electrolysis), chemicals (by chemical reduction) or heat (by
thermolysis); these methods are less developed for bulk generation in comparison to chemical paths
derived from hydrocarbons. The discovery and development of less expensive methods of bulk
production of hydrogen will accelerate the establishment of a hydrogen economy.
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Recent Advances in Hydrogen Production
•
•
•
•
•
•
Electrolysis of water
Nuclear, renewable, conventional electricity
Reforming
Catalysis
Natural gas, coal, oil, diesel, biomass
Photoelectrical, Photo biological, thermal dissociation
Obstacles to a H2 Production
There are two obstacles to a hydrogen-economy.
Feed Reservoir
Temperature
Indicators
Reactor
Vaporizer
Thermal well
Two way
stopcocks
Catalyst
Heater
Insulation
H2 gas
Condenser
Acetaldehyde
It takes a lot of volume (or energy) to store hydrogen – Usually five times or so the volume, at
reasonable pressures, needed to store an equivalent amount of energy with gasoline.
• There is no hydrogen infrastructure: Making the transition to a hydrogen economy might mean
having to scrap the fossil fuels infrastructure that has already developed. One company that has
made progress on refueling equipment is Stuart Energy.
Using synthetic fuels and low carbon storage tanks might surmount both of these problems. For
example, it is possible, using a catalyst, to make fuels such as methanol, ethanol or any carbon
based fuel and that yields to get separate as alcohols / aldehydes.
•
Thermal Degradation: Catalyst activity loss due to thermal damage us often a serious problem in
supported metal catalysts (Pt-Al2O3, Ni-Al2O3 etc) and oxide catalysts with large surface areas
(SiO2-Al2O3, Al2O3, Zeolites, iron-molybdate etc).
The major thermal damages to the catalysts are:
1) Loss pf metal surface area due to crystalline growth.
2) Loss of support surface area duet to pore collapse and
3) Transformation of the catalytic phase into a non-catalytic phase.
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C. Bharadwaj Kumar, P. Sreedhar, J. Santoosh, S. S.Chaitanya. B, Y.Satya Prasad, M. Devika
Experimental Setup
The process figure is shown below.
In the process the feed (Ethanol) is given at the Feed Reservoir and that can be comes to enter into
vaporizer with the help of a two way feed stock, so here the liquidus form of feed is get converts
into the gaseous form and then it enters into the fixed bed reactor.
Fixed Bed Reactor
In any catalytic process we must use the process in a fluidized bed with some height if it may
change or not depending upon the process but in our process bed is fixed and it is placed at the
starting of the process and it can be changed or moved in the height of the bed depends upon the
durability of the catalyst. Hence as copper catalyst is moderately good enough durable so that our
process reactor knows also as fixed bed reactor.
The fixed bed reactor compounded (combined) with that of thermal well and vaporizer. The
thermal well is having the thermocouple which is connected to the pyrometer which gives the
temperature with in the reactor and also the reactor is wounded by a heating tape to generate the
desired temperature varying with a dimmer start and it covers by an insulation to avoid heat losses.
Potential uses for hydrogen
When properly stored, hydrogen as a fuel burns in either a gaseous or liquid state. Motor vehicles
and furnaces can be converted to use hydrogen as a fuel. Hydrogen has actually been used in the
transportation, industrial, and residential sectors in the United States for many years. Currently,
industries use large quantities of hydrogen for refining petroleum, and for producing ammonia and
methanol. The space shuttle uses hydrogen as fuel for its rockets.
Burning of H2 creates less air pollution than gasoline or diesel. Hydrogen also has a higher flame
speed, wider flammability limits, higher detonation temperature, burns hotter, and takes less energy
to ignite than gasoline. This means that hydrogen burns faster, but carries the danger of pre-ignition
and flashback. While hydrogen has its advantages as a vehicle fuel it still has a long way to go
before it can be used to substitute for gasoline. This is mainly due to the investment required top
develop a hydrogen production and distribution infrastructure.
8. CONCLUSION
Energy supplies in the 21st century will be challenged as fossil fuel reserves decline, human
consumption increases, and greenhouse gasses accumulate to further damage the atmosphere.
These challenges will be met by innovative solutions to enable the hydrogen economy; to replace
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Recent Advances in Hydrogen Production
petrochemical fuels with hydrogen for use in fuel cells and internal combustion engines. One of the
most difficult challenges is to produce hydrogen at a cost competitive with current fuel pricing
(fossil fuel or natural gas)
Acetaldehyde is the byproduct in the above process and is a colorless liquid with a pungent, fruity
odor. It is primarily used as a chemical intermediate, principally for the production of acetic acid,
pyridine and pyridine bases, peracetic acid, pentaeythritol, butylene glycol, and chloral.
Acetaldehyde is a volatile and flammable liquid that is miscible in water, alcohol, ether, benzene,
gasoline, and other common organic solvents.
REFERENCES
[1]
[2]
[3]
[4]
Hydrogen generation by catalytic reforming by J.A. Dumestic, R. R. Davada.
Highly efficient hydrogen generation from Quantum Sphere, 2006.
Hydrogen production by M. Scot, Auckland, New Zealand.
Hydrogen production from wikkipedia and other websites.
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Design of ADRC Load Frequency
Controller for Three Area Power System
Pallavi Gothaniya
Electronics & Communication dept.
University college of enginnering(RTU)
Kota (Raj.)India
ABSTRACT
In this paper a novel control strategy, the active disturbance rejection control (ADRC), is applied
to the representative power system problem. In the ADRC framework, the disturbance and
unmeasured dynamics associated with processes are treated as an additional state variable,
which is then estimated and compensated for in real time. This reduces a normally complex,
time-varying, nonlinear, and uncertain dynamic process to an approximately linear, timeinvariant, cascade-integral form, where a simple proportional-derivative (PD) controller
suffices. Furthermore, with only two tuning parameters, the controller provides a simple, easyto-use solution to complex engineering problems in practice. Simulation studies are performed
on system has three areas. Each area has three parallel-operating generating units that are
owned by different generation companies (GenCos). Every generating unit has a non-reheat
turbine unit, a generator, and a governor. The simulation results verified the effectiveness of the
ADRC.
Keywords: Automatic Generation Control (AGC), Area Control Error (ACE), Optimal Linear
Quadratic Regulator (LQR), DC Link Introduction
1. INTRODUCTION
Power systems are used to convert natural energy into electric power. They transport electricity to
Factories and houses to satisfy all kinds of power needs. To optimize the performance of electrical
equipment, it is important to ensure the quality of the electric power. It is well known that threephase alternating current (AC) is generally used to transport the electricity. During the
transportation, both the active power balance and the reactive power balance must be maintained
between generating and utilizing the AC power. Those two balances correspond to two equilibrium
points: frequency and voltage. When either of the two balances is broken and reset at a new level,
the equilibrium points will float. A good quality of the electric power system requires both the
Frequency and voltage to remain at standard values during operation. Thus a control system is
essential to cancel the effects of the random load changes and to keep the frequency and voltage at
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Design of ADRC Load Frequency Controller for Three Area Power System
the standard values .Although the active power and reactive power have combined effects on the
frequency and voltage, the control problem of the frequency and voltage can be decoupled . For
stable operation of power systems, both constant frequency and constant tile-line power exchange
should be provided [4]. Therefore an area control error (ACE), which is defined as a linear
combination of power net- Interchange and frequency deviations [1], is generally taken as the
controlled output of LFC. As the ACE is driven to zero by the LFC, both frequency and tie-line
power errors will be forced to zeroes [1].
The applications show that, for a number of complex control problems, ADRC results in extremely
simple controller design but achieves high performance in tracking And disturbance rejection. The
basic idea of ADRC is to use an extended state observer (ESO) to estimate the internal and external
disturbances in real time. Then, through disturbance rejection, the originally complex and uncertain
plant dynamics is reduced to a simple cascade integral plant, which can be easily controlled by a
PD controller. Two important features of ADRC are 1) its lack of dependence of the model; and 2)
the excellent disturbance rejection performance.
2. DYNAMIC MODELING OF THE POWER SYSTEM
In this section, the dynamic model of a three-area interconnected power system will be developed.
each area of the power system consists of one generator,one governor, and one turbine unit. It
includes three inputs, which are the controller input U(s) (also denoted as u), load disturbance
∆PL(s), and tie-line power error ∆Ptie(s), one ACE output Y(s), and one generator output ∆f. ∆Pv is
denoted as valve position change, ∆Pe electrical power, and ∆Pm mechanical power. The ACE
alone is a measurable output. For each area, it is defined by (1), where B is area frequency response
characteristic [1].
ACE= ∆Ptie+B∆f
(1)
We use transfer function (TF) to model the one-area generator unit. Let the transfer function from
∆Pe(s) to ∆Pm(s) be
GET(s) = NumET(s) / DenET(s),
where NumET(s) and DenET(s) are the numerator and denominator of the GET(s). The
representations of NumET(s) and DenET(s) vary from different generating units. For the non-reheat
turbine unit, GET(s) is given by
G ET (s) =
Num ET (s)
1
=
Den ET (s) (Tg s + 1)(Tch s + 1)
(2)
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Pallavi Gothaniya
Y(S) = GP (S) U(S) + GD(S)∆PL(S)Gtie(S)∆Ptie
(3)
controller that minimizes the cost of the system in state variable form is a function of the present
states of the system weighted by the components of a constant gain matrix K1 of dimension m*n
and can be defined by .
u =-K x
(4)
Define the transfer function of the generator as
G GEN (s) =
1
1
=
Den M (s) Ms + D
(5)
where DenM(s) represents the denominator of GGen(s). The Laplace transform of the one-area power
generating plant can be simplified as where
(6)
GP (S) =
RBNumET (S)
NumET (S) + RDenET (S) DenM (S)
(7)
GD (S) =
− RBDen ET (S)
NumET (S) + RDenET (S)DenM (S)
(8)
Gtie( S ) =
NumET ( S ) + RDenET ( S ) DenM ( S ) − RBDen
NumET ( S ) + RDenET ( S ) DenM ( S )
(9)
3. THE INTERCONNECTED POWER SYSTEMS
Tie-Lines
In an interconnected power system, different areas are connected with each other via tie-lines.
When the frequencies in two areas are different, a power exchange occurs through the tie-line that
connected the two areas. The tie-line connections can be modeled. The Laplace transform
representation of the block diagram in Figure 7 is given by
1
s
∆Ptie (s) = Tij ( ∆Fi(s) - ∆Fj(s))
(10)
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Design of ADRC Load Frequency Controller for Three Area Power System
where ∆Ptieij is tie-line exchange power between areas i and j, and Tij is the tie-line synchronizing
torque coefficient between area i and j. From Figure 1, we can see that the tie-line power error is
the integral of the frequency difference between the two areas
Area Control Error
we need to include the information of the tie-line power deviation into our control input. As a
result, an area control error (ACE) is defined as
ACEi =
∑ ∆Ptieij + Bi∆fi
j =1,.... n , j ≠1
(10)
where Bi is the freqyency response characteristics of area [i].
Bi = Di +
1
Ri
(11)
is completely controllable, there exists a feedback matrix K such that (A-BK) is a stable matrix.
Parallel operation
If there are several power generating units operating in parallel in the same area, an equivalent
generator will be developed for simplicity. The equivalent generator inertia constant (Meq), load
damping constant (Deq) and frequency response characteristic (Beq) can be represented as follows
Meq = ∑ Mi
(12)
Deq = ∑ Di
(13)
i =1,... n
i =1,... n
1
+ ∑ Di
i =1,...n Ri
i =1,...n
Beq = ∑
(14)
DESIGNING OF ACTIVE DISTURBANCE REJECTION CONTROLLER
The ADRC for area 1 can be designed and represented by the following
sZ(s) = (A − LC)Z(s) + BU(s) + LY (s)
(19)
U (s) = k (R(s) − Z (s)) − k Z (s) − k Z (s)
(20)
U(s) =
U O (s) − Z4(s)
b
(21)
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Pallavi Gothaniya
where The ADRCs for the other two areas have the similar structure to the one for area 1. Where
 Z 1 (s) 
 ( s)
Z2 
Z (s) = 
,A=
 Z 3 (s)


 Z 4 ( s)
0
0

0

0
1 0 0
0 1 0
,B =
0 0 1

0 0 0
4 ω0
0 
 2
0 
 , L = 6 ω0 , k1 = ω3c ,
4 ω30
b 
 4
 
0 
 ω0 
k 2 = 3ωc2 , k 3 = 3 ωc andC = [1 0 0 0]
The ADRCs for the other two areas have the similar structure to the one for area 1. The design
parameters of the ADRCs in different areas are given in Table I.
Table I: ADRC parameters
Order of ESO
ωC
Area1
3
4
Area 2
3
4
Area 3
3
4
ωO
b
20 78.77
20 76.25
20 74.27
The test system has three areas. Each area has three parallel-operating generating units that are
owned by different generation companies (GenCos). Every generating unit has a non-reheat turbine
unit, a generator, and a governor. The schematic diagram of the system is shown in Figure 4, where
the three areas are connected with each other through tie-lines. In this figure, ∆PL1, ∆PL2, and ∆PL3
are power load changes added to the three areas.The tie-line synchronizing coefficients between
any two areas are T12 = 0.2 p.u./rad., T23 = 0.12 p.u./rad. and T13 = 0.25 p.u./rad.. The ramp rate
factor that is used to describe the ate of change in the power plant output is given as
Figure 1: Schematic diagram of the three-area nine-unit power system[9]
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Design of ADRC Load Frequency Controller for Three Area Power System
α=
Ramprate× 5min
Regulation requirement
a step load change with large amplitude is added to each area. The purposeof this case is to test the
robustness of the controllers against large disturbances. The amplitudes of the load changes for the
three areas are ∆PL1 = 100 MW (0.1 p.u.), ∆PL2 = 80MW (0.08 p.u.) and ∆PL3 = 50 MW (0.05
p.u.) respectively. The power loads are added to the systems at t = 2 second. However, the control
effort of ADRC shows an overshoot at the switching edge of the load change. This is due to a slight
lag of ESO in response to the external disturbance. Nevertheless the overshoot magnitude of
ADRC is reasonable. So it will not affect their which the regulation requirement for each area is
100 MW.
4. CONCLUDING REMARKS
This paper proposed an ADRC based decentralized LFC for an interconnected three-area power
system. Our control objective is to regulate ACE, frequency errors, and net tie-linepower
deviations to zeroes in the presences of power load changes and system uncertainties. The ADRC
is designed forthe power system containing both thermal and hydraulic turbines. The simulation
results further verified the effectiveness.
delta pc
0.4
0.3
0.2
0.1
0
delta F
0
-0.01
-0.02
-0.03
-0.04
0
A CE
-0.01
-0.02
-0.03
-0.04
0
2
4
6
8
10
12
14
16
18
20
time(sec.)
Figure 2: System responses of area 1(∆Pc (p.u.), ∆f (Hz), ACE (p.u.))
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Pallavi Gothaniya
0.5
d e lta p c
0.4
0.3
0.2
0.1
0
time(sec.)
d e lta F
0.05
0
-0.05
ACE
0.05
0
-0.05
0
2
4
6
8
10
12
14
16
18
20
Figure 3: System responses of area 2 (∆Pc (p.u.), ∆f (Hz), ACE (p.u.))
0.5
d e lta p c
0.4
0.3
0.2
0.1
0
time(sec.)
d e lta F
0.05
0
-0.05
A CE
0.05
0
-0.05
0
2
4
6
8
10
12
14
16
18
20
Figure 4: System responses of area 3 (∆Pc (p.u.), ∆f (Hz), ACE (p.u.))
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Design of ADRC Load Frequency Controller for Three Area Power System
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in Web Processing Lines,” inProceedings of IEEE International Conference on Control
Applications,Singapore, Oct. 2007, pp. 842–848.
[9] Sun, and Z. Gao, “A DSP-Based Active Disturbance Rejection Control Design for a 1-kW H-bridge DCDC Power Converter,” IEEETransactions on Industrial Electronics, vol. 52, no.5, pp. 1271–1277,
Oct.2005.
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LQR Based LFC for Two Area Interconnected Power
System with AC/DC Link
Pallavi Gothaniya
Electronics & Communication Dept.
University College of Enginnering (RTU), Kota(raj.)India
ABSTRACT
Recently, LQR controllers have received extensive attention and research. Accordingly, there is
an increasing interest in LQR controller. The widely used classical integer order proportional
integral controller and proportional integral derivative controller are usually adopted in the load
frequency control (LFC) and automatic generation control (AGC) to improve the dynamic
response and to eliminate or reduce steady state errors. In this paper LQR controllers are used to
improve dynamic stability and response of LFC and AGC system.This paper presents the
MATLAB simulink dynamic model of the load frequency control (LFC) of a realistic two area
power system having diverse sources of power generation. The DC link is used in parallel with
AC tie line for the interconnection of power system. The power system simulation is done using
MATLAB simulink and control problem is solved using MATLAB programming. An optimal
output feedback controller with pragmatic viewpoint is presented. Optimal Gain settings of the
output feedback controller with DC tie line are obtained following a step load disturbance in
either area by minimizing the quadratic performance index. Simulation results show that the
system with AC-DC parallel tie line achieves better performance in the presence of plant
parameter changes and system nonlinearities.
Keywords: Automatic Generation Control (AGC), Area Control Error (ACE), Optimal Linear
Quadratic Regulator (LQR), DC Link Introduction Introduction
∆Fi : Incremental change in frequency subscript referring to area (i=1,2,3; j=1,2,3)
∆Pgi: Incremental change in generator power output
∆Pdi : Incremental change in load demand
∆Xgi: Incremental change in governor valve position
∆Ptiei,j : Incremental change in tie-line power (MW)
Tp: Electric system time constants
Ri : Speed regulation parameter, Hz/p.u.MW
Tgi: Speed governor time constant of area, s
Kri,Tri: Reheat coefficient’s & reheat time’s
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LQR Based LFC for Two Area Interconnected Power System with AC/DC Link
Bi : Frequency bias constant (p.u.MW/Hz)
∆ACEi: Change in Area control error’s
Tti: Turbine time constants
Kgi: Speed governor gain
Kt1: Reheat thermal turbine gain constant
Ti,j: Synchronizing coefficient of ac tie-line
A, B, C, System matrices associated with state, control, output
D: and disturbance vectors respectively
X, U, Y, State, control, output and disturbance vectors
Pd: respectively
1. INTRODUCTION
AGC regulates the power output of electric generators within prescribed area in response to
changes in system frequency, tie-line loading, and relation of these to each other.This maintains the
scheduled system frequency and established interchange with other areas within predetermined
limits.The operation and control of these interconnected power systems is no longer a simple task
for power engineers. In the event of availability of a suitable AGC scheme, the selection of proper
approach for its effective implementation has a vital role [1-3].
Regulator design for interconnected power system AGC function is a multivariable system design
problem and its effective study can be justified using modern control techniques for investigations
[4-7]. The recent advancement in optimal control theory and availability of high speed digital
computers coupled with enormous capability of handling large amount of data motivated the power
system engineers/researchers to devise advanced AGC strategies.
Through various research publications, it has been established that with optimal control strategies
designed using linear regulator theory, ameliorated system dynamic performance with greater
stability margins as compared to that obtained with conventional AGC regulators can be achieved
[10].
From the study of research papers reported in literature relating AGC of power systems, it is
evident that almost all the works have been carried out considering area interconnection as AC
transmission link. However, the works incorporate novel concepts relating to control aspects,
power system structures and their operational and economic considerations. The transmission
systems have gone through major changes in the form of transmitting electrical power at higher and
higher voltage levels over the large distances. One of the major development in this area is the use
of HVDC transmission systems on power scenario in India in late ninety’s. Due to the inherent
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Pallavi Gothaniya
technical and economic merits of HVDC transmission systems over AC/EHVAC transmission
systems, more DC Equations transmission systems up to a voltage level of 765 kV were developed
in 2007 and more HVDC transmission systems have been envisaged for future [9].
Therefore, it becomes necessary to incorporate the dynamics of HVDC systems while designing
the AGC scheme for interconnected power systems. A two-area interconnected power The
requirements and benefits of using parallel AC/DC transmission links as system interconnection
are highlighted [8, 9].This paper is dedicated to represent the optimal AGC regulator designs based
on an optimal Linear Quadratic Regulator theory. The optimal AGC regulator is designed for a
multi-area interconnected reheat type power system with AC Tie-line only and DC Link parallel
with AC transmission lines considering 0.01 p.u.MW perturbation in one of the area are considered
for the study. Power system dynamic performance has been studied by investigating the response
plots of the disturbed areas ∆F1, ∆F2, ∆F3, ∆ACE1, ∆ACE2 and ∆ACE3,with nominal system
parameters.
A. LQR controller
The theory of optimal control is concerned with operating a dynamic system at minimum cost. The
case where the system dynamics are described by a set of linear differential equations and the cost
is described by a quadratic functional is called the LQ problem .The optimal control problem for a
linear multivariable system with the quadratic criterion function is one of the most common
problems in linear system theory. it is defined below:
Given the completely controllable plant
X& = AX + BU
(1)
Where x is the n×1 state vector, u is the p×1input vector. A and B are, respectively n ×n and n×p
real constant matrices, and the null state x=0 is the desired steady-state.
The control law
U=-K x(t)
(2)
K minimizes the following performance index subject to the initial conditions X (0) ≅ X0 ;
J=
1∞ T
T
∫ (X QX + U RU )dt
20
(3)
Where Q is n× n positive definite, real, symmetric, constant matrix and R is p×p positive definite,
real, symmetric, constant matrix. The optimal controller that minimizes the cost of the system in
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LQR Based LFC for Two Area Interconnected Power System with AC/DC Link
state variable form is a function of the present states of the system weighted by the components of
a constant gain matrix K1 of dimension m*n and can be defined by .
K1 can be obtained from the solution of the reduced matrix Riccati equation given below
AT P1 + P1 A − P1 BR −1 B T P1 + Q = 0
, K = R −1 B T P1
The acceptable solution of K is that for which the system remains stable. For stability all the eigen
values of the matrix (A-BK) should have negative real parts. From equation (4), we get the optimal
control of our choice. So for it was assumed that all the states are available for feedback.
Practically it is very difficult and costly to measure and to have readily available information of all
the states in most of the large power systems. Usually reduced number of state variables or a linear
combination thereof is available. The output feedback controller is as described below
U=-Kx
(5)
where K is an output feedback gain matrix of dimension (n×p). In the optimal control scheme the
control inputs are generated by means of feedbacks from all the controlled output states with
feedback constants to be determined in accordance with optimality criterion
There are several ways to solve this optimal control problem. we use the Lyapunov function
approach.
Substituting (2) into (1), we obtain
X& = AX − BKX = (A − BK)X
(6)
Since the (A,B) pair is completely controllable, there exists a feedback matrix K such that (A-BK)
is a stable matrix.
2. MULTI-AREA INTERCONNECTED POWER SYSTEM MODEL
The transfer function model of two area interconnected power system under consideration is shown
in Fig. 2. The system dynamic equations in state space for this model can be givenas:
d/dt (X) = AX + B U + D Pd
(7)
Y=CX
(8)
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Pallavi Gothaniya
Where, A, B, C & D are system state, control, measurement and disturbance matrices respectively
and X, U, Y & Pd are state, control, output and disturbance vectors of compatible dimensions
respectively. From the transfer function model of Fig.2, the structure of vectors X, U and Pd may be
developed as follows
System State Vector
[X] = [∆F1 ∆Pg1 ∆Pr1 ∆Xg1 ∆F2 ∆Pg2 ∆Pr2 ∆Xg2 ∆Ptie u1 u2]T Without DC link
Where
u1 = ∫ACE1dt ,u2 = ∫ACE2dt
[X] = [∆F1 ∆Pg1 ∆Pr1 ∆Xg1 ∆F2 ∆Pg2 ∆Pr2 ∆Xg2 ∆Ptie u1 u2 ∆Pdc]T Parallel AC/DC link
Control Vector
[U] = [∆Pc1, ∆Pc2]T
Disturbance Vector
[Pd] = [∆Pd1, ∆Pd2]T
Figure 1: Two equal area power system interconnected through AC-DC parallel tie lines
Fig.2. Transfer Function Block diagram of Power System model
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LQR Based LFC for Two Area Interconnected Power System with AC/DC Link
3. SYSTEM MATRICES
The matrices, A, B and D as appeared in equations (1) and (2) can be obtained using the structures
of state, control and disturbance vectors and the transfer function model representation of Fig.1.
Using the numerical values of system variables as given in Appendix, the corresponding coefficient
matrices are derived as
 − 0 . 05
 0

 0

 − 5 . 208
 0

A =  0
 0

 0

 5 . 378
 0 . 425

 0
B
T
D
T
=
=
6
0
0
0
0
0
0
−6
− 0 .1
− 1 . 566
1 . 666
0
0
0
0
0
0
0
− 3 . 333
3 . 333
0
0
0
0
0
0
0
0
0
0
− 12 . 500
0
0
− 0 . 05
0
6
0
0
0
0
0
6
0
0
0
0
0
0
− 0 .1
− 1 . 566
1 . 666
0
0
0
0
0
0
0
− 3 . 333
3 . 333
0
0
0
0
0
− 5 . 208
0
0
− 12 . 500
0
0
0
0
0
0
0
0
− 5 . 378
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0 . 425
0
0
0
−1
0
0
 0

0
0

 − 6

 0
0
12
0
. 500
0
0
0
0
0
0
0
0
12
. 500
0
0
0
0
0
0
0
0
0
0
0
0
− 6
0
0
0
0
0
0
0
0
0
0
0 
0

0
0

0
0

0

0
0

0 
0 

0 
0 

0 
The appropriate modification can be done in the structure of matrix ‘A’ to consider the area
interconnection as AC link in parallel with DC link in power system model. Consideration of DC
link dynamic model as state variable will have the additional non-zero elements of ‘A’ matrix as;
A(1, 12) = -5.988, A(12, 1) = 5.0, A(12, 12)= -5.0 The rest of the additional elements are zero.
Design Matrices
The state cost weighting matrix ‘Q’ and control cost weighting matrix ‘R’ are selected as an
identity matrix of compatible dimensions respectively.
4. SIMULATION RESULTS AND ANALYSIS
The optimum values of the for the output feedback controller by minimizing the cost function for
the power system with AC tie line corresponding to nominal system parameters is K
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Pallavi Gothaniya
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
del F area 1
del F area 2
-0.8
0
5
10
15
20
25
30
Fig. 3 Dynamic Response of F for area 1 and 2 with aclink
0.4
0.3
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
-0.5
-0.6
0
5
10
15
20
del ACE area 1
del ACE area 2
25
30
Fig. 4 Dynamic Response of ACE for area 1 and 2 with ac link
0.15
0.1
0.05
0
-0.05
-0.1
-0.15
del ACE area1
del ACE area2
-0.2
0
5
10
15
20
25
30
Fig. 5 Dynamic Response of ACE for area 1 and 2 with ac-dc link
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LQR Based LFC for Two Area Interconnected Power System with AC/DC Link
0.3
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
0
del F area 1
del F area 2
5
10
15
20
25
30
Fig. 6 Dynamic Response of ∆F for area 1 and 2 with ac-dc link
5. CONCLUSION
The system dynamic performance in the wake of load disturbance in either of the area of
interconnected power system has been investigated. The optimal AGC regulator using LQR control
strategy is designed and their feasibility is studied. This proposed optimal LQR gives much better
results than the Integral regulator. The power system dynamic performance of reheat thermal
power plants can be compensated effectively by incorporating DC link in parallel with AC Tie-line
in place of AC Tie-line only as area interconnection between power system areas.
TABLE I
Quantity
Symbol
50Hz
Electric system time
constants
Tp1 = Tp2
20sec
B1=B2
0.425
Incremental change
in load demand
∆Pd
0.02 p.u.MW
R1=R2
2.4 Hz/
MW
Synchronizing
coefficient of AC tieline
2πT12
0.545p.u.MW
Speed governor time constant of
area, s
Tg1 = Tg2
0.08 sec
a12
-1
Reheat coefficient’s
Kr1 = Kr2
0.5 sec
DC gain constant
Kdc
1
reheat time’s
Tr1 = Tr2
10 sec
DCtime constant
Tdc
0.2
Turbine time constants
Tt1 = Tt2
0.3 sec g
Electric system gain
Kp1 = Kp2
120 Hz/ p.u.
MW
Quantity
Symbol
nominal freq.
F
Frequency bias constant
Speed regulation
Hz/p.u.MW
parameter,
p.u.
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Pallavi Gothaniya
REFERENCES
[1] Sivanagaraju S., Sreenivasan G.“Power System Operation and Control”, 1st edition Pearson Publishing
Company Ltd., New Delhi,2009
[2] .Moorthy P. S. R. “Power System Operation and Control,” Tata Mc Graw Hill publishing Company
Limited. 1984.
[3] O. I. Elgerd and C. Fosha (1970, Apr.), “Optimum megawatt frequency control of multi-area electric
energy systems,” IEEE Trans. Power App. Syst., vol.PAS-89, no. 4, pp. 556–563.
[4] P. Kumar and Ibraheem (1998),“Dynamic performance evaluation of 2-area interconnected power
systems: A comparative study,” J. Inst. Eng., vol.78, pp. 199–208.
[5] Kothari, Nanda and Das (1989, May), “Discrete mode AGC of a two area Reheat Thermal System with
new Area Control Error”, IEEE Trans., PAS.-4(2), 730 738.
[6] Ibraheem, Kumar, P. and Kothari, D. P.( 2005, February) “Recent philosophies of automatic generation
control strategies in power systems,” IEEE Trans. Power System, vol. 11, no. 3, pp. 346- 357.
[7] Loi Lei Lai, “Intelligent system applications in power engineering” John Wiley & Sons, 1998
[8] Mathur H. D. (2006), “A comprehensive analysis of intelligent controllers for load frequency control,”
Proc. IEEE Power India Conf., vol. no.07803-9525.
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132
Real Time Power Generation Using Piezoelectric
Ceramic Disc for Low Voltage Appliances
Arpit Bansal1, Akshita Jain2, Rachit Agrawal3, Pradeep Kumar4, Ashutosh Gupta5
Dept.of Electronics & Communication, AMITY UNIVERSITY, NOIDA (UP)
ABSTRACT
This paper presents the useful involvement of piezoelectric ceramic disc for real time power
generation. The presented paper demonstrates the working model of Real Time Power
generation using Piezoelectric Ceramic Disc for staircase lighting system. This concept can also
be used in various low voltage based applications. The positive feature of using this type of
staircase-lighting system is its cost effectiveness, availability of components and reusability of
resources. The energy generated by the proposed model helps us to eliminate the external power
supply, decreasing the cost and increasing its stability.
Keywords: Piezoelectricity, Pressure Switches, Photocell, piezoelectric ceramic plates
1. INTRODUCTION
The most common light switches in the residence and commercial buildings, are the toggle
switches i.e. the switch has to be manually turned on by human hand and then it has to be turned
off. Similarly there are the “rocker” and “push” switches. These are the most commonly used
switches because of their simplicity. Use of pressure switches and the concept of piezoelectricity
make the lighting system both automatic and self sustained. Using the pressure switch and
piezoelectric ceramic plate beneath each step avoids the user to manually “on” and “off” the lights.
Moreover, piezoelectric plate help to convert the mechanical vibrations into corresponding voltage
which in turn can be stored and later on used as power supply. Thus, making the complete system
self sustaining and efficient. With the help of basic electronic components this concept can be
implemented which would generates much effective results rather than a conventional staircaselighting system. A number of researches have been done in the past on the staircase lights in order
to make it more cost effective and productive. Starting from 1995, Thomas T Nagano in his ‘Step
Lighting Apparatus’[1], configured to facilitate installation on the edge or nose of a step, The
apparatus includes a plurality of channels, each of which holds a strip of low voltage light fixtures.
His invention was remarked as a great success in this field but later was not appreciated due to
difficulties in installation process. Then the concept of piezoelectricity was introduced by Henry A.
Sodano, Daniel J. Inman, Gyuhae Park [2]. They proposed the use of piezoelectric materials to
capitalize on the ambient vibrations surrounding a system. This is one method that has seen a
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Arpit Bansal, Akshita Jain, Rachit Agrawal, Pradeep Kumar, Ashutosh Gupta
dramatic rise in use for power harvesting. This research also had a same fate as of Step lighting
system discussed earlier. Further, Chao-Tung Kuo [3] proposed in his research the ways to provide
an emergency lighting illumination appliance to save the expense of additionally purchasing
emergency light. Another objective of the invention herein is to provide emergency lighting
function illumination appliance that has lighting capability when mains power is normally supplied
and also during mains power outages. The most attractive part of this invention is that circuit layout
of the building needs not to be modified. Thus, to reduce expenditures, increase lighting area
coverage, and facilitate evacuation efficiency. Further with the inventions, people started to think
towards the reusability of the power as well as cost effectiveness. A number of researches were
done in order to get the reusability of electricity. Like, Ankur Tiwari, Meraj Ahmad, Arun Tripathi
and Ankita Mishra[4] proposed in their paper the ways to use a piezoelectric device to obtain
electrical energy with the help of mechanical pressure. When pressure is applied, electric potential
produces electric current which is used to glow road lights and then is used to charge mobile
phones via some USB device. Thus, a huge success was achieved in using the piezoelectricity on
such a large scale. Further advancing towards renewable resources again, Pramathesh. T, Ankur. S
[5] proposed in their project the use of piezoelectricity. Piezoelectricity is appearance of electric
potential across the sides of crystal when subjected to mechanical stress. Some of the applications
are: Special flooring tiles with piezoelectric crystals, Specially designed road which generates
electricity with the use of piezoelectric effect, Dance floors with piezoelectric crystals installed,
Piezoelectric crystals installed in shoes. After such a huge success in the field of renewable form of
electric energy, further inventors were forced to think big. For which Scott D Holland, Joseph F.
Witt [6] proposed in his research how the staircase lightning system is used for lightning spiral as
well as straight and regular staircases with the help of photocells. In this there is a main source
which is used for providing electrical energy to each staircase to the lights connected to each of the
stairs .These lights are preferably those lights which draw very little current such as Light Emitting
Diodes (LEDs). The main drawback is the cost of the photocells that are used to illuminate the
staircase. Photocells are very expensive as a result the effective cost increases if this system is
implemented at large scale. Thus, above inventions, researches, paper forced us to think in the
direction of using piezoelectricity in staircase lighting systems.
This paper mainly focuses on merging of piezoelectricity and staircase-lighting Systems. Simple
design of the overall system and involvement of the piezoelectric plates under each step has
successfully targeted in lowering the cost and efficient effectiveness of the staircase-lighting
system. Our staircase system can be implemented at number of places like simple household stairs,
in theatres, in hospitals, at airports, or at any other place where there is a great to and fro motion of
the people. The system can be easily made more durable with involving the rubber gaskets, sealing,
to protect it from environmental issues. This system is so simple that it can also be implemented
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Real Time Power Generation Using Piezoelectric Ceramic Disc for
fo Low Voltage Appliances
easily by any household engineer. Moreover, in case of power failure the designed system
syst
can
illuminate the staircases. The use of piezoelectric plates helps the rechargeable batteries to charge
themselves up to that level that can light the staircases. The most important drawback that we have
tried to eliminate is the usage of costly components
nents as well as inaccurate photocells to illuminate
the stairs. Hence, we have tried to get a cost effective as well as an efficient system.
2. DESIGN ANALYSIS & WORKING
The lighting system comprises of basic electronic components which are arranged in a very
ver simple
manner. The basic principle, working behind the staircase lights is the pressure switches placed
beneath every step along with the piezoelectric ceramic plates, so that whenever they are being
pressurized the system works as well as the battery gets
ge charged up. The main emphasis is laid on
the use of piezoelectric ceramic plates rather than any sensors, solar cells, or photocells. Further the
design has been improved from all the previous other designs of Automatic lighting staircase
systems available
able in the market. Components like resistors, capacitors, switches, LEDs, speakers,
transistors, different ICs, etc. are used to implement our idea. The basic design of our system that is
involved under every step is shown in Fig. 1.
Fig. 1 Basic Circuit under every Step
When the user steps on the staircase, the push button switch gets pressed. The switch remains in the
stressed position till the user is standing on the particular step. The circuit gets complete. The first
NPN transistor receives the
he current and it amplifies it for 555 Timer IC. The 555 Timer IC are used
in order to produce a particular amount of delay in the system. Collector terminal is connected to
the 2nd pin of 555 Timer IC, it triggers the 555 Timer IC. Pin 6 (Threshold) and Pin
P 7 (Discharge)
are connected together to 33mF capacitor which is the discharge capacitor. Discharge capacitor is
the deciding component of the circuit. This capacitor gets fully charged. The output from pin 3 of
555 Timer IC is fed to input of music generating
rating IC UM66. These ICs are being manufactured in
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A Sustainable Approach - ISBN: 978-93-83083-73-2
135
Arpit Bansal, Akshita Jain, Rachit Agrawal, Pradeep Kumar, Ashutosh Gupta
such a way that they produce a particular type of music. As UM66 gets the input it produces the
musical sound. This sound is sustained as long as discharged capacitor (33mF) which is connected
to the ground pin of UM66 IC gets discharged. Then the output music sound is fed to 2nd NPN
transistor for amplification of voltage, so that the sound can be transferred to the speakers. From
the speaker user get the musical sound generated by the IC UM66. On the other hand, Red LEDs
also remains high till the same discharge capacitor gets fully discharged. Hence, on pressurizing
the push button, both the music and LEDs gives the indication that someone has gone through that
particular step. Once again, when the button is pushed again, capacitor gets charged for that instant
of time and gives the output till it gets fully discharged. By, changing the value of capacitor (33mF)
we can change the time interval for which it gives the output. During the continuous motion on the
steps for long period of time, the piezoelectric ceramic plate helps to convert the mechanical
vibration produced every time to the corresponding voltage which is fed to the rechargeable
battery. Thus, battery also gets charged continuously. Piezoelectric ceramic plates acts as
transducer to change mechanical energy into electrical energy.
3. EXPERIMENTAL IMPLEMENTATION AND RESULTS
An experiment illustrating our concept involves a small model which has been made using the
components. The specifications of the components used are as follows (For one step) Resistors of
values 1kohm, 33kohm, 100ohm, 470ohm, Capacitors of values 33mF, NPN transistor (BC 547),
555 Timer IC, Music generating UM66 IC, LEDs (Red), Pressure Switches, Piezoelectric ceramic
plates (20mm).As soon as the user steps on the first step of the staircase, the light and sound for
that step becomes active and remains in on state until the discharge capacitor gets discharged. Now,
as the user move to next step the lights and sound for second step becomes active and after fixed
interval of time, light and sound of first step blows off.
Fig. 2 and Fig. 3 shows, how the LEDs are being working by applying the pressure on push button
switches along with piezoelectric plates.
Fig. 2 Actual circuit for one step
Fig. 3Working prototype of the system
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Real Time Power Generation Using Piezoelectric Ceramic Disc for Low Voltage Appliances
Table 1 Voltage generated by the proposed model.
Piezoelectric Material
Voltage generated by
proposed model[volts]
0.48
Standard Output
Voltage[volts]
0.50
Piezoelectric ceramic disc20mm(Diameter)
As shown in Table I, a voltage of 0.48 volts is being developed with the help of piezoelectric
ceramic disc (20mm). Due to small size of piezoelectric ceramic plates the voltage generated is
very low. We can use this voltage to run low voltage devices like low voltage lighting system at
home, low voltage motors etc. Further improvement in the size of piezoelectric ceramic disc can
increase the output voltage.
4. CONCLUSION
As the result shows when the pressure is applied on the piezoelectric ceramic plates, there is a
deformation of charge carriers inside the piezoelectric plate which result in the production of
electric field, and therefore an electric potential is developed across the plate, and the electric
potential is used to produce electric current which is used to glow LEDs, sound and we are able to
charge the battery used in the setup. Presented work enlightens the self sustaining part of the
automatic staircase switching lights model as it takes minimal voltage for the commencement of
the process.
The discoveries also resonate with the larger subject area as the setup can be used to harvest power.
Research shows that a 60 kg man produces 0.1 watt energy with the help of piezoelectric plate. By
implying our model on the staircases used in day to day life we would be able to harvest a lot of
energy. We can replace the present trend of staircase lighting system with presented model so that
it encourages the use of renewable resources and helps us in near future. Also, it helps in driving a
number of low voltage devices.
REFERENCES
[1] Thomas T. Nagano Cerritos, California-US Patent, and Patent No: 5,430,627 Date of Patent:Jul4, 1995.
[2] Henry A. Sodano, Daniel J. Inman- LA-UR-03-5397- ‘A Review of Power Harvesting From Vibrations
Using Piezoelectric Materials’ LAUR-03-5397, The Shock and Vibration Digest , 36(3), 197-205, 2004.
[3] Chao Tung Kuo, ”Emergency Lighting Function Illumination Appliance” Patent No. 7,057,351 B2,
Date of Patent: Jun 6 , 2006.
[4] AnkurTiwari, Meraj Ahmad, ArunTripathi and AnkitaMishra.” Energy Harvesting Through
Piezoelectric Cells for Commercial Use” VSRD Journal, Volume 2, Issue 6, 2012.
[5] Pramathesh.T, Ankur.S “Piezoelectric Crystal: Future Of Electricity” International Journal of Scientific
Engineering and Technology vol.2, No.4,pp 260-262, April1, 2013.
[6] Scott D. Holland, Joseph F. Witt, “Stair Lighting System and Its Method of Implementation”Patent No:
US 7,954,973 B1, Date of Patent: Jun 7, 2011
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Smart and Functional Materials in Technological
Advancement of Solar Photovoltaic’s
R.C.Sharma1 and Ambika2
1
Department of Applied Sciences and Humanities, Dronacharya College of Engineering, Khentawas,
Gurgaon-123506, Haryana, India.
2
Software Engineer, Miracle Technology, Noida-201301, U.P., India.
ABSTRACT
Increased power production from solar energy is dependent on more research efforts aimed at
developing and fine tuning new ways to make solar power increasingly competitive with
traditional energy sources. Pure silicon is today the most important material in solar cell panels.
The fabrication of solar photovoltaic with enhanced efficiency and affordable cost has been the
great challenge to Technocrats and Scientists in sharing the future energy needs. The use of
smart and functional materials can play an important role in this direction. The present paper
analyze the recent advances in Photovoltaic technology in reference to material characterization,
multi-junction solar cells and concentrating photovoltaic technology for maximum utilization of
solar energy.
Keywords: Photovoltaic, solar energy, Functional materials, efficiency.
1. INTRODUCTION
Science and technology in the 21st century will rely heavily on the development of new materials
that are expected to respond to the environmental changes and manifest their own functions
according to the optimum conditions. The development of smart and functional materials will
undoubtedly be an essential task in many fields of science and technology such as information
science, microelectronics, computer science, medical treatment, life science, energy, transportation,
safety engineering and military technologies. Materials development in the future, therefore, should
be directed toward creation of hyper-functional materials which surpass even biological organ in
some aspects. The current materials research is to develop various pathways that will lead the
modern technology toward the smart and functional systems. Functional materials cover a wide
range of organic and inorganic and oxide functional materials such as the ferroelectric BaTiO3, the
magnetic field sensor of La1-xCaxMnO3, surface acoustic wave sensor of LiNbO3, liquid
petroleum gas sensor of Pd-doped SnO2, semiconductor light detectors (CdS, CdTe), high
temperature piezoelectric Ta2O5, the electric voltage induced reversible coloring of WO3, and high
temperature superconductors etc. In recent years, techniques for epitaxial crystal growth have made
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it possible to grow oxides and metal thin films on silicon substrates, and this is the first step to
integrate functional materials with the logic system. A key requirement in preparations of materials
is to control the structural and compositional evolution for achieving superior properties.
With the continual increase in demand for global energy, scientists across the world are working to
find a way to transition from fossil fuels to renewable energy sources that are more efficient and
environmentally friendly. The sun delivers more energy to the Earth’s surface in one hour than the
entire world uses in one year, and realizing the full potential of solar power will require finding
effective, inexpensive ways to utilize this vast energy source.
The development of the thin-film polycrystalline CdTe/CdS solar cell is driven by the possibility of
producing photovoltaic modules more cheaply than ever before. As CdTe has a near optimal band
gap (1.45 eV) for solar absorption, may be doped n- or p-type and has high optical absorption
above the band gap, it was recognized early on as a good solar cell absorber layer1. However,
homo-junction devices are impractical due to unacceptably high surface recombination loss. To
avoid this the p-CdTe/n-CdS/TCO/glass super substrate configuration was developed 2. The n-CdS
forms one side of the electrical junction and acts as a window layer. Organic-lead halide perovskite
solar cells have recently emerged as one of the most promising candidates for the next generation
of solar cells, with record efficiencies increasing from just a few percent to more than 15 percent in
just a few years. However, these solar cells have exclusively used organic hole conducting
polymers, which are one of the components responsible for conducting electricity in the cells.
These organic polymers are generally expensive because they are synthetically produced and must
be pure for photovoltaic applications. Use of inorganic materials for perovskite solar cells, which
provides a lower-cost alternative to the organic polymers, has recently identified 3. A new
technology called "screening-engineered field-effect photovoltaic’s," or SFPV, has been developed
which enables low-cost, high efficiency solar cells to be made from virtually any semiconductor
material4.
Theoretical Consideration
The total emitted spectral Electroluminescence (EL) photon flux is given by the reciprocity
relation,
(1)
Where φBB is the black body photon flux, V is the internal voltage applied to the pn-junction, q is
the electron charge, kb is the Boltzmann constant, and T is the temperature of the cell. Thus, the
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R.C.Sharma and Ambika
spectral EL is connected to the (External Quantum Efficiency) EQE via the voltages of the subcells.
This relationship enables us to extract the internal open-circuit voltage VOC, which is generated
across each sub-cell when operating under an injection carrier density equivalent to the photogenerated carrier density under illumination.
The high-energy luminescence is emitted from Boltzmann distributed carriers,
(2)
where N is the number of occupied states, and ∆E is the difference in carrier energy with respect to
the Fermi energy of the semiconductor. Hence, both the exponentially rising and the falling edge of
the luminescence can be identified in the reciprocity relation: the low-energy slope by the EQE and
the high-energy slope by the black body photon flux.
It should be noted that the calculation of the voltage with Eq. (1) necessitates scaling by one
remaining unknown constant in the reciprocity relation, which basically is the absolute photonic
irradiance of the cell. Consequently, the sum of the derived sub-cell voltages features a constant
offset with regard to the actual voltage. This offset δV, which remains constant under variation of
current density, is determined from an automated comparison with a measured I-V curve of the
sample under known illumination condition:
(3)
where is the calculated sub-cell voltage for a current density JEL,i equal to the current density JPhoto,i
generated under illumination.
Using above relations, it is possible to extract the spectral EL of monolithically stacked multijunction solar cells, the I–V characteristics of all contributing sub-cells within this stack.
2. THIN-FILM POLYCRYSTALLINE CDTE/CDS SOLAR CELL
High optical absorption by a material is directly related to its conversion efficiency. CdTe with n or
p type doping has high optical absorption above band gap and has been considered a suitable
material for solar cell. A homojunction solar cell using CdTe are impractical since most absorption
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Smart and Functional Materials in Technological Advancement of Solar Photovoltaic’s
of the solar spectrum occurs within 1-2 um of the CdTe surface and this makes the surface
recombination loss unacceptably high. To avoid this the p-CdTe/n-CdS/TCO/glass “superstrate”
configuration shown in Fig. 1 was developed [2]. The n-CdS (Eg =2.42 eV) forms one side of the
electrical junction and acts as a window layer. Fig. 2 shows a calculated carrier generation profile
in a CdTe/CdS structure resulting from illumination by the AM1.5 solar spectrum. Carriers
generated in the CdTe are likely to be collected and contribute to the photocurrent, while those in
the CdS are lost. Thin CdS, 50-100 nm, is therefore preferred to allow above-gap optical
transmission. The CdTe need only be 1-2 um thick, but may be thicker to ensure homogeneity.
Cells fabricated in this materials system are remarkably tolerant to the deposition methods used 5.
However, the majority of cells, and all those with notable conversion efficiencies, were subjected
to a post-growth treatment of the CdTe.
Variations of the process are many but this so called ªactivationº or “type conversion” process
usually involves annealing in the presence of CdCl2. This results in an order of magnitude increase
in the conversion efficiency and improvements in the open circuit voltage and short circuit current.
The maximum efficiencies reported to date are 15.8% in 1993 and 16.0% in 19986: advances have
slowed in recent years. Study of cells fabricated with the CdCl2 methods have revealed a wealth of
detail. It is considered that the CdCl2 treatment effects the conversion of the CdTe from n- to p-type
, lowers series resistance and is accompanied by a change in current transport mechanism from
tunneling/interface recombination to recombination in the depletion region7. Although the
maximum efficiency of the cells has been estimated to be over 29% 8, the best reported to date fall
some way short of that.
Fig. 1 The superstrate configuration used for CdTe/CdS heterojunction solar cells.
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R.C.Sharma and Ambika
Fig. 2 Stimulated profile of carriers generated in a CdTe/CdS heterostructure by AM 1.5
Sunlight.
The function of the transparent conducting oxide (TCO) coated glass substrate is to provide a
highly transparent and conductive contact to the CdS window layer. Both SnO2 and In2O3-SnO2
(ITO) have been used successfully, but the latter is sometimes avoided to rule out diffusion of In.
The n-CdS window layer is an essential component of the cell as it is highly conductive (n=1016
cm-3), thin to allow high transmission (50-100 nm) and uniform to avoid short circuit effects.
Techniques used to deposit it include physical vapor deposition (PVD) and close space sublimation
9
. The current-voltage characteristics of CdTe cell with different Schottky barrier heights is given
in table 2.
Table 2: Current- voltage characteristics of a CdTe cell with different Schottky Barrier
heights.
Barrier height(eV)
Voc (eV)
Jsc (mA/cm2)
FF (%)
Efficiency (%)
0.1
916
28.36
75.91
19.72
0.2
916
28.35
75.76
19.67
0.4
830
28.23
69.80
16.36
_______________________________________________________________________________
3. DESIGN PRINCIPLE OF MULTI-JUNCTION SOLAR CELL
The InGaAs/GaAsP quantum wells in general use are composed of InGaAs well layers, GaAsP
barrier layers, with GaAs interlayer between them. Here, the GaAs interlayer are optional, and the
band for a single well has a stepped structure for relatively thick interlayer, whereas it has a
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Smart and Functional Materials in Technological Advancement of Solar Photovoltaic’s
rectangular line-up in the absence of inter-layers. The proposed design principle can be
summarized into the following three points:
•
•
•
InGaAs wells should be made thinner and deeper for a given band-gap in order to achieve both
a higher absorption coefficient for 1e-1hh transitions, and to reduce the compressive strain
accumulation.
GaAs inter-layers with thicknesses of just a few nanometers can effectively extend the
absorption edge to longer wavelengths without introducing compressive strain, and can also
suppress lattice relaxation during growth.
GaAsP barriers should be thinner than 3ῆnm to facilitate tunneling transport, and their
phosphorus content should be minimized while avoiding detrimental lattice relaxation.
Multi-junction Solar Cell has been proved to be highly promising for utilization of solar power.
The InGaAs/GaAsP strain-compensated multiple quantum wells (MQWs) are promising narrowband gap materials that can be pseudo-lattice-matched to Ge or GaAs10. By alternately growing
InGaAs absorber layers with compressive strain and GaAsP strain-balancing layers with tensile
strain on nanometer-scale, a large number of MQWs can be epitaxially grown on GaAs. The
targeted band gap of 1.20–1.25ῆeV, including quantum confinement effects, can be obtained by
adjusting the composition and the thickness of each layer. Incorporation of such MQWs or superlattice structures has been proposed not only for current-matched tandem solar cells but also for
high-efficiency single-junction solar cells11.
Although the potential of InGaAs/GaAsP MQW solar cells has been experimentally demonstrated
in terms of improvement in device performance, understanding of physics in quantum structures,
and implementation of MQW into tandem devices 12, challenges still exist from the viewpoints of
both crystal growth and structural design toward practical application. The growth challenge is
primarily attributed to the difficulty in controlling the strain balance, especially in crystals with
high indium and phosphorus contents, where lattice relaxation gradually occurs during formation of
the hetero-interface between the two oppositely strained layers. This results in severe crystal
degradation as a large number of layers are grown, even though, in theory, MQWs can be
epitaxially stacked infinitely if the compressive and tensile strain completely balance each other out
13
.
The difficulty in achieving a suitable structural design is due to the trade-off between light
absorption and carrier collection, which is a general challenge not only for InGaAs/GaAsP MQWs
but also other material systems14. For complete absorption of photons with energies above the
effective band gap of the MQW, the excitations involving ground-state electrons and holes, that is,
1e-1h transitions, must be sufficiently large. This necessity, however, requires a large number of
wells to be stacked, which imposes more difficulty in extracting carriers through the MQW regions
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R.C.Sharma and Ambika
because of the weakened electric field in the thickened i-region. To overcome this transport
problem, various strategies based on MQW structural design have been proposed. These include
using a superlattice with ultra-thin barriers to facilitate tunneling, limiting the number of thick
wells to suppress non-radiative recombination, using step-designed MQWs for efficient thermionic
carrier escape, and performing quick carrier extraction from deep wells via resonant-tunnelingassisted processes15. A comparison of Multi-junction solar technology with other technology is
given in table 3.
Table 3 Comparison of Multi-junction solar technology with other technology16.
4. CONCENTRATING PHOTOVOLTAIC TECHNOLOGY
Concentrating photovoltaic technology is another promising field of development. Instead of
simply collecting and converting a portion of whatever sunlight just happens to shine down and be
converted into electricity, concentrating PV systems use the addition of optical equipment like
lenses and mirrors to focus greater amounts of solar energy onto highly efficient solar cells.
Although these systems are characteristics material dependent and generally pricier to manufacture,
they have a number of advantages over conventional solar panel setups and encourage further
research and development efforts16.
Fig.3 Concentrating photovoltaic Technology: The sun’s rays are concentrated before hitting
the solar cells producing a greater output. Heat sinks have to be provided to dissipate the
increased heat and the panels work best in sunny weather.
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Smart and Functional Materials in Technological Advancement of Solar Photovoltaic’s
5. SUMMARY
This paper analyze the role of functional materials in enhancing the solar energy conversion. The
technological advancement in solar photovoltaic materials with enhanced conversion efficiency is
promising. More research and development is needed in Multi-junction solar Photovoltaic
Technology and Concentrating Photovoltaic Technology to make it more efficient and economical
to meet our future energy needs.
6. ACKNOWLEDGEMENT
Author R.C.Sharma is highly grateful to management and administration, Dronacharya College of
Engineering Gurgaon for providing excellent R & D environment and encouragement during the
work.
REFERENCES
[1] N. Zanio, R.K. Willardson, A.C.Beer (Eds.)(1978), Semiconductors and Semimetals, vol. 13, Wiley,
New York.
[2] D. Bonnet, H. Rabenhorst(1972): 9th IEEE Photovoltaic Specialists Conference, IEEE, Silver Springs,
MD, 1972, p. 219.
[3] Prashant Kamat, John A. Zahm and Raymond Fung,(2012) Journal of the American Chemical Society,
Jeffrey Christians,
[4] Alex Zettl, William Regan, Steven Byrnes, Will Gannett, Onur Ergen, Oscar Vazquez-Mena and Feng
Wang. Zettl (July 2012) Screening-Engineered Field-Effect Solar Cells, Journal of Nano Letters Alex
Zettl, William Regan, Steven Byrnes, Will Gannett, Onur Ergen, Oscar Vazquez-Mena and Feng Wang.
Zettl.
[5] R.W. Birkmire, E. Eser(1997)Annu. Rev. Mater. Sci. 27 pp 625.
[6] T. Aramoto, S. Kumusawa(1997) Jpn. J. Appl. Phys. 36 pp 6304.
[7] S.A. Ringel, A.W. Smith, M.H. MacDougal, A. Rohatgi(1991) J. Appl. Phys. 70 (2) pp 881.
[8] A. De Vos, J.E. Parrot, P. Baruch, P.T. Landsberg, (1994): 14th European Photovoltaic Solar Energy
Conf., Amsterdam, pp. 1315.
[9] D. Bonnet(1997) 14th PVSEC, WIP, Barcelona.
[10] SM.Bedair, Katsuyama T, Chiang PK, El-Masry NA, Tischler M, Timmons M(1984) GaAsP-GaInAsSb
Superlattices: a new structure for electronic devices. Journal of Crystal Growth, 68, pp 477–482.
[11] KWJ Barnham(1990). A new approach to high-efficiency multi-band-gap solar cells. Journal of Applied
Physics ; 67 pp 3490–3493.
[12] JGJAdams, BC Browne, IM Ballard, JP Connolly, NLA Chan, A Loannides , W Elder, PN Stavrinou ,
KWJ Barnham , NJ Ekins-Daukes (2011). Recent results for single-junction and tandem quantum well
solar cells. Progress in Photovoltaics: Research and Applications; 19: pp 865–877.
[13] H Fujii , Y Wang, K Watanabe, M Sugiyama, Y Nakano(2012), Suppressed lattice relaxation during
InGaAs/GaAsP MQW growth with InGaAs and GaAs unltra-thin interlayers, Journal of Crystal Growth
; 352, pp 239–244.
[14] H Fujii , Watanabe K, Sugiyama M, Nakano Y(2012) Effect of quantum well on the efficiency of carrier
collection in InGaAs/GaAsP multiple quantum well solar cells. Japanese Journal of Applied Physics ;
51: 10ND04.
[15] Y Wen , YWang , K Watanabe, M Sugiyama, Y Nakano(2013) . Effect of GaAs step layer thickness in
InGaAs/GaAsP stepped quantum-well solar cell. IEEE Journal of Photovoltaics 3: pp 289–294.
[16] M Yamaguchi, ; T Takamoto, ; K Araki, (2006). "Super high-efficiency multi-junction and concentrator
solar cells". Solar Energy Materials and Solar Cells 90 pp18–19.
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Sputtering Pressure Dependent Structural, Optical and
Hydrophobic Properties of DC sputtered Pd/WO3 thin films
for Hydrogen Sensing Application
Sonam Jain1, 2, Amit Sanger1, Ramesh Chandra1*
1
Nanoscience Laboratory, Institute Instrumentation Centre,
Indian Institute of Technology Roorkee, Roorkee-247667, India
2
Centre of Nanotechnology, Indian Institute of Technology Roorkee, Roorkee-247667, India
ABSTRACT
Hydrogen is known as one of the clean and efficient energy source with a potential to be used as
a fuel for industrial applications. The present study investigates the influence of Sputtering
pressure on hydrogen sensing response of Pd/WO3nanostructured thin films. The bilayer
Pd/WO3 thin films were prepared by Dc magnetron sputtering on the glass and silicon
substrates. The thin films were characterized using X-ray diffraction (XRD),UV-Vis-NIR
spectrophotometer, Atomic force microscope (AFM) and Contact angle measurement. The
crystallite sizewas found to increase with increase in sputtering pressure. The wettability of the
samples was found to increase with increase in pressure. The value of roughness obtained from
AFM showed the similar trend. The temperature dependent hydrogen response was studied in
temperature range from 50-150oC.The as deposited WO3 samples were found to be transparent
however the transparency decreases on hydrogen exposure due to the formation of blue tungsten
bronze. The effect of water vapor during dehydrogenation was studied. The change in sensing
response of the thin film was correlated with the hydrophobicity of the samples. Stability of the
samples was observed to be retained after hydrogenation & dehydrogenation cycle. The response
time of around 1sec for the thin film prepared at 20 mtorr is reported.
Keywords: Sputtering, Metal oxide, Porosity, Hydrophobicity, Hydrogen Sensing.
1. INTRODUCTION
Hydrogen is considered as a future fuel for storing and transporting the energy as it can be easily
transformed into electrical energy and vice-versa with a greater degree of efficiency (55-70%)
[1].Hydrogen has a high standard heat of combustion of 141.9 kJ/g. Hydrogen is a clean energy
resource producing a benign oxidation product-water. Currently, hydrogen is used as a popular
process gas in petroleum refining, chemical and food industries, chlorine production, monitoring of
nuclear waste, fuel cells etc. However, effective and fast hydrogen gas detection technologies are
crucial for large scale hydrogen based applications.
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Sputtering Pressure Dependent Structural, Optical and Hydrophobic Properties of DC sputtered Pd/WO3 thin
films for Hydrogen Sensing Application
Tungsten oxide is a promising hydrogen gas sensing material due to its chemical stability and a
very high diffusion coefficient [2]. It is an indirect band gap n-type semiconductor with
reportedband gap in the range from 2.6-3.1 eV [3]. Till date WO3 thin films have been prepared by
several methods[4] including vacuum evaporation, sol-gel, Pulse laser deposition(PLD), sputtering.
Sputtering is used in our study for the WO3 thin film preparation due to its ability to produce
uniform and crystalline films. Later is considered as a novel method for thin film deposition as it
allows to control the structural properties by varying sputtering parameters [5].
In this study, we explain the hydrogen sensing mechanism of bilayer Pd/WO3 thin films prepared
by Dc magnetron sputtering. The influence of sputtering pressure on structural, optical and
hydrophobic properties was studied and henceforth the change in hydrogen sensing performance of
as-prepared samples is reported.
2. EXPERIMENTAL DETAILS
WO3 and bilayer Pd/WO3 nanostructured thin films were deposited on glass and silicon substrates
by Dc magnetron sputtering using 25mm diameter and 3mm thick tungsten (99.96% purity) and Pd
(99.95% purity) targets. High purity inert gas (99.99% pure Ar) and reactive gas (99.99% pure O2)
were used for sputtering. The substrate were initially cleaned by rinsing in ultrasonic bath of
acetone for 10 min and then blown dry in air to remove surface contaminants. The sputtering
pressure was varied from 5 to 20mTorr, keeping all other parameters constant. The target was presputtered for 5 min to remove negative ions on the surface of target. Afterwards, Pd was deposited
on the WO3film surface for5sec sputtering at 30W. Table1 lists the deposition parameters used:
Table 1. Deposition parameters for WO3 thin films
Sputtering Parameters Target
Tungsten(W)
Base Pressure
Working Pressure
Deposition time
Power
Substrate Temperature
Target-substrate distance
Sputtering Gases
Substrate
6x10-6 torr
5-20 mtorr
5 min
100W
300oC
50mm
Ar,O2
Glass, Silicon
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3. RESULTS & DISCUSSIONS
The XRD patterns of WO3 nanostructured thin films prepared at varying sputtering pressure are
shown in Fig.1. The dominant peak obtained at 28o is attributed to the It(002) plane of monoclinic
phase of WO3. Monoclinic phase can exist at room temperature, hence it is acknowledged as a
stable phase [3]. The particle size of the thin films increases and hence the crystallinity of the thin
films improved as the sputtering pressure is increased from 10-20 mtorr. The particle size can be
estimated from Scherrer’s formula[6] following in equation(1):
t=0.9 λ/(βcosθ)(1)where, λ and θ are the wavelength of Cukα(1.542 Aῆ) and Bragg’s angle
respectively, βis FWHM (Full Width Half Maximum) of the dominant peak.
The variation of crystallite size ‘t’ with sputtering pressure can be explained on the basis of
relationship between mean free path , molecular diameter of sputtering gas and distance between
target and substrate inside sputtering chamber as given in equation (2) :
Fig.1. XRD patterns of WO3 thin films at different sputtering pressure
λ = kT/(√2πPγ2)(2)
where, λ is the mean free path, γ is the molecular diameter of sputtering gas, P is pressure of
sputtering gas.
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Sputtering Pressure Dependent Structural, Optical and Hydrophobic Properties of DC sputtered Pd/WO3 thin
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(a)
(b)
Fig.2 (a) variation of mean free path and no. of collisions with pressure, (b) dependence
ofparticle size and dislocation density with sputtering pressure.
The variation of dislocation density with the sputtering pressure is shown in Fig.2. Dislocation
density gives the number of crystal defects in a film. Dislocation density (D.D) can be estimated
using the following relation given in equation (3):
D.D = 1/t2 lines/m2
(3)
Dislocation density was observed to be minimum at 20mtorr indicating minimum number of crystal
defects at that particular pressure.
Optical properties of the thin films were observed to be strongly dependent on the sputtering
pressure. The optical transmittance spectra of WO3 thin films for different sputtering pressure is as
shown in fig.6. The optical transmittance spectra of the thin film increases from 40 % to 92% at
500nm with increase in sputtering pressure to 20mtorr. At lower sputtering pressure, oxygen is
unable to deposit with tungsten and hence films formed at lower pressure exhibited a lower optical
transmittance. On the other hand, both oxygen and tungsten gets deposited forming nearly
transparent films with higher optical transmittance (90%) at higher sputtering pressure. On
depositing Pd onto WO3 thin films a considerable decrease in transmittance spectra was observed.
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Fig.3 (a) and (c) show the transmittance and energy band gap at different sputtering
pressure, Fig. (b) and (d) shows the transmittance and band gap for sample
samp deposited at 20
mtorr.
The optical energy band gap is calculated using Tauc’s relation [7]:
(αhν)m =β(hν-Eg)
(4)
where, hν is theincident photon energy and Eg is the optical band gap of the material. α is
absorption coefficient, β is a transition probability parameter. Parameter m is transition
coefficientand corresponds to ½ and 2 for indirect and direct band gap respectively.
re
The band gap
of the films decreased from3 to 2.7 eV with increase in sputtering pressure from 10mtorr to 20
mtorr. The decrease in band gap with pressure is due to the fact that Pd occupies the interstitial
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Sputtering Pressure Dependent Structural, Optical and Hydrophobic Properties of DC sputtered Pd/WO3 thin
films for Hydrogen Sensing Application
layers between the valence band and conduction band thereby decreasing band gap.The obtained
band gap values are in close agreement with those reported in literature.
The refractive index of the thin films can be determined using swanepoel’s envelope method [8]:
n= [N+(N2-no2n12)1/2]1/2
(5)
where, N=(no2+n12)/2 + [2non1 (Tmax-Tmin)/(Tmax*Tmin)] ; no and n1 are the refractive indices of
air and substrate respectively.
Fig.4 shows the dependence of refractive index with sputtering pressure. The refractive index of
the thin films decreased to 2.18 at 20 mtorr. The decrease in refractive index may be attributed to
the decrease in the packing density of the thin films formed at higher sputtering pressure.
Fig.5 shows the 3-D AFM micrographs of Pd/WO3 thin films at different sputtering pressure. It is
evident from the micrographs that the roughness of the films increases with sputtering pressure.
The variation in the roughness of the films can be attributed to the increase in crystallite size with
sputtering pressure which in turn increases the roughness of the films.
Fig. 4(a) variation of thickness and porosity with pressure, (b) variation of refractive index
and packing density with pressure.
Hydrophobicity of the bilayer Pd/WO3 thin films was calculated using contact angle measurement.
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Fig: 5 Variation of Contact angle and Roughness with Sputtering Pressure.
A surface is considered as hydrophobic if θ>90o[9].The variation of hydrophobicity (contact angle)
and roughness of the film surface with sputtering pressure
pressu is shown in fig.5. Both are observed to
show the same trend. The reason for this may be attributed to the inability of the liquid to fill
cavities at the rough surface and thereby creating air pockets at solid-air-liquid
solid
interface.
4. HYDROGEN RESPONSE OF PD/WO3 THIN FILMS:
The sensing response of bilayer Pd/WO3 thin film is observed using resistance change on
hydrogenation. Fig.6 shows the variation of resistance of Pd/WO3 bilayer films with time during
hydrogenation/dehydrogenation cycle. It has been observed
obse
that the sensor response rose
considerably on increasing sputtering pressure. The reason may be attributed to reducing the grain
size and increasing porosity with increasing pressure.Sensor
pressure.
Response(S.R) can be estimated using
(Ro-Rg)/Rg, where, Ro and Rg are the resistances of the Pd/WO3 films in air and in presence of
hydrogen respectively. The response time of around 1sec is reported for the film prepared at 20
mtorr.In air, Oxygen chemisorbs on the surface of the WO3 thin films and trap free electrons from
the conduction band of WO3 due to their high electron affinity and results in an electron depletion
region. This build up a large resistance in that area due to lack of carriers and the potential barrier
induced inhibits the carrier mobility [10].
O2 + 2e- 2O-(ads)
(7)
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Sputtering Pressure Dependent Structural, Optical and Hydrophobic Properties of DC sputtered Pd/WO3 thin
films for Hydrogen Sensing Application
Fig. 6 (a) hydrogenation/de-hydrogenation
hydrogenation for sample prepared at 20 mtorr, (b) sensor response as
a function of temperature.
However, when H2 is introduced it reacts with the oxygen species. Catalyst dissociates the H2
molecules to H atoms which reacts with tungsten oxide to form blue tungsten bronze[11]. Electrons
released in the process are given back to the semiconductor which lowers the potential
pot
barrier and
allows the current to flow thereby increasing conductivity.
2Hῆ (ad-atoms) + O- (ads) H2O + e-
(8)
xHῆ (ads) + WO3HxWO3
(9)
5. CONCLUSION
Nano-structured
structured bilayer Pd/WO3 thin films were fabricated using DC magnetron sputtering at
varying sputtering pressure. The hydrophobic, structural and optical properties of the thin films
were investigated. All the samples prepared were observed to show a stable monoclinic phase. The
porosity (12.67%), roughness (2.64nm)) and contact angle (96.9o) were found to be maximum at
20mtorr. The sensor response also showed highest value at 20mtorr. The reason for this may be
attributed to the fact that the high porosity and small grain size facilitates the diffusion of the
hydrogen
en within thin film lattice, thereby considerably increasing the sensor response. Studies
show that metal oxide Pd/WO3 thin films prepared at 20mtorr proves to be a fast and stable
hydrogen sensing material.
REFERENCES
[1] T. Hüberta,L. Boon-Brett G. Black U. Banach, Hydrogen sensors – A review, Sensors and Actuators B
157 (2011) 329– 352
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A Sustainable Approach - ISBN: 978-93-83083-73-2
153
Sonam Jain, Amit Sanger, Ramesh Chandra
[2] M. Ando, R. Chabicovsky, M. Haruta, optical hydrogen sensitivity of noble metal-tungsten oxide
composite films prepared by sputtering deposition, Sensors and Actuators B 76 (2001) 13-17.
[3] Muhammad Z. Ahmad, Abu Z. Sadek ,M.H. Yaacob, David P. Anderson, GlennMatthewsa, Vladimir B.
Golovkod, Wojtek Wlodarski, Optical characterization of nanostructured Au/WO3thin films for sensing
hydrogen at low concentrations, Sensors and Actuators B 179 (2013) 125– 130.
[4] S.H. Mohamed, H.A. Mohamed, H.A. Abd El Ghani, Development of structural and optical properties
of WOxfilms upon increasing oxygen partial pressure during reactive sputtering,Physica B 406 (2011)
831–835.
[5] Meng Zhao, JianxingHuanga, Chung-Wo Ong, Preparation and structure dependence of H2sensing
properties of palladium-coated tungsten oxide films, Sensors and Actuators B 177 (2013) 1062– 1070.
[6] B.D. Cullity, Elements of X-ray Diffraction, 2nd edn Addison-Wesley, London,1978. 102
[7] J. Tauc, Amorphous and Liquid Semiconductors, Plenium Press, New York, 1974,p. 159.
[8] R Swanepoel, Determination of the thickness and optical constants of amorphous silicon,J. Phps. E: Sci.
Instrum, Vol. 16, 1983.
[9] R.N. Wenzel, Ind. Eng. Chem. 28 (1936) 988
[10] A. Boudiba, C. Zhang, C. Navio, C. Bittencourt, R. Snyders, M. Debliquy, Preparation of highly
selective, sensitive and stable hydrogen sensors based on Pd-doped tungsten trioxide, Procedia
Engineering 5 (2010) 180–183.
[11] V. Srivastava, K. Jain, Highly sensitive NH3 sensor using Pt catalyzed silica coating over WO3 thick
films, Sensors and Actuators B 133 (2008) 46–52.
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An Assessment of Perform Achieve and Trade Mechanism A Case Study of Industries in District Ropar, Punjab
Ravneet Kaur
Research Scholar, Panjab University, Chandigarh, India
ABSTRACT
Climate change is the critical challenge faced by the humanity which needs to be addressed with
good scientific understanding and knowledge as well as the steps initiated at national and global
level. National Mission for Enhanced Energy Efficiency (NMEEE) is an innovative initiative
taken by Government of India to address climate change and to provide legal consent for the
implementation of energy efficiency measures through the institutional mechanism of Bureau of
Energy Efficiency (BEE). NMEEE has four components. This paper highlights one of the
components, Perform Achieve Trade (PAT), which means market based mechanism to enhance
cost effectiveness of improvements in energy efficiency in energy intensive large industries
through certification of energy savings that could be traded.
Punjab Energy Development Agency (PEDA) has been designated by the Punjab State as the
nodal agency for planning, overseeing and guiding the activities to mitigate the climate change.
PEDA is indulged in accomplishing monitoring procedure, feedbacks and verification regarding
targets assigned by Government under PAT. The paper uses both Primary, as well as Secondary
sources to analyse the contribution of PEDA in PAT scheme by undertaking a study on
industries situated in District Ropar. Paper will discuss methods to check targets, achievement
awards, failure penalties, discussion and audit reports of PEDA and future planning of
industries to achieve energy efficient targets. This paper is beneficial for planners of PAT
mechanism and the agencies who conduct workshops for State Designated Agencies and
Designated Consumers.
Keywords: Perform Achieve and Trade, Punjab Energy Development Agency, Industries,
National Mission for Enhanced Energy Efficiency
1. INTRODUCTION
In recent years, both developed and developing countries have paid greater attention to improving
Energy Efficiency (EE) because of the rising prices of electricity and the growing demand for finite
and diminishing fossil fuel resources. Improved energy efficiency is one of the most cost-effective
ways to reduce global greenhouse gas emissions. It also enhances energy security of the countries
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Ravneet Kaur
by reducing energy demand. To date, energy efficiency has become one of the priority fields in the
energy, economic and climate change policies of many countries globally. [1] India is faced with
the challenge of sustaining its rapid economic growth while dealing with the global threat of
climate change. The EC Act, 2001 received the assent of the President on the 29th September, 2001
as an Act to provide for efficient use of energy and its conservation and for matters connected
therewith or incidental thereto. The Bureau of Energy Efficiency (BEE) under the provisions of the
EC Act, 2001 has been established with effect from 1st March, 2002 with the primary objective of
reducing energy intensity of the Indian economy. This is expected to be achieved with active
participation of all stakeholders, resulting in accelerated and sustained adoption of energy
efficiency in all sectors. [2]
Punjab Energy Development Agency (PEDA) has been designated by the State as the nodal agency
responsible for spearheading Energy Efficiency efforts to identify and oversee energy conservation
programs, including those mandated by Bureau of Energy Efficiency. In addition to planning,
overseeing and guiding the activities, PEDA will coordinate, regulate and enforce the provisions of
the EC Act 2001. Central Government initiated a step National Mission for Enhanced Energy
Efficiency (NMEEE) to fight against climate change.
National Mission of Enhanced Energy Efficiency: NMEEE is one of the eight missions under
the National Action Plan on Climate Change (NAPCC). The scheme has been approved by the
cabinet and it got implemented on 2010-2011. The objective of the Mission is to achieve growth
with ecological sustainability by devising cost effective strategies for end- use demand side
management. The Ministry of Power (MoP) and BEE have been entrusted with the task of
preparing the implementation plan for the NMEEE and to upscale the efforts to create and sustain
market for energy efficiency to unlock investment of around Rs. 74,000 Crores. NMEEE has four
major components which provide for a multi-pronged approach for achieving energy efficiency in
the country.
1.
Perform Achieve and Trade (PAT): It is a market, based mechanism to enhance cost
effectiveness of improvements in energy efficiency in energy-intensive large industries and
facilities, through certification of energy savings that could be traded. The scheme includes
the following project steps:
[1]United Nation Economic Commission for Europe, Promoting Energy Efficiency Investments for Climate Change
Mitigation
and
Sustainable
Development,
2012-2014,
retrieved
from
http://www.unece.org/energy/gee21/promoting_eei.html as on 5-4-2014
[2]Ministry of Law, Justice and Company Affairs, The Energy Conservation Act- 2001, 2001, retrieved from
http://powermin.nic.in/acts_notification/energy_conservation_act/introduction.htm as on 1-4-2014
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An Assessment of Perform Achieve and Trade Mechanism - A Case Study of Industries in District Ropar,
Punjab
Goal setting: Set a specific energy consumption (SEC) target for each plant,
depending on level of energy intensity (specific energy consumed = energy use /
output) of that plant. The target will specify by which percentage a plant has to
improve its energy intensity from the base line value in a period of three years.
o Reduction phase: Within a three-year period (2009-2012) the designated
consumers try to reduce their energy intensity according to their target.
o Trading phase: Those consumers who exceed their target SEC will be credited
tradable energy permits. These permits can be sold to designated consumers who
failed to meet their target. Designated Consumers who fail to achieve their target
have to compensate this failure by buying permits. If they fail to do either of this,
they may have to pay penalties.
Market Transformation for Energy Efficiency: MTEE is another scheme launched by
BEE to achieve the aim of the National Mission on Enhanced Energy Efficiency. The
scheme aims to accelerate the shift to energy efficient appliances in designated sectors
through innovative measures and to make the products more affordable. Two sub
programmes are now operational and they are the BLY (Bachat Lamp Yojana) and the
SEEP (Super Efficient Equipment Programme).
o
2.
3.
Energy Efficiency Financing Platform (EEEP): The national Mission on Enhanced
Energy Efficiency aims to create a mechanism that would help finance, demand side
management programmes in all sectors by capturing future energy savings. The finance
costs will be recovered from the energy savings, which will also reduce the subsidy bill of
the state government. EEFP will provide instruments like bankable detailed project reports
and other risk mitigation measures to enhance comfort for lenders towards aggregated
energy efficiency projects.
4.
Framework for Energy Efficient Economic Development (FEED): The Enhanced
Energy Efficiency mission aims to develop Fiscal instruments to promote energy efficiency
in a way that allows for the creation of mechanisms to help finance demand side
management programmes in all sectors by capturing future energy savings. The
Framework for Energy Efficient Economic Development (FEEED), has been
conceptualized to achieve this objective and two fiscal instruments to promote energy
efficiency, namely:
o The Partial Risk Guarantee Fund (PRGF)
o Venture Capital Fund for Energy Efficiency (VCFEE) are being developed[3]
[3]Punjab State Action Plan On Climate Change, Chapter 10: Mission on Enhanced Energy Efficiency, 2012, retrieved
from http://www.indiaenvironmentportal.org.in/files/file/Punjab_action_plan_on_Climate_change.pdf as on Jan10,
2013, 13:32
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Ravneet Kaur
Perform Achieve and Trade: PAT programme aims to promote energy efficient technology,
which is one of the factors of the National Mission on Enhance Energy Efficiency (NMEEE)
launched by the Government of India. The PAT mechanism is implemented by the Bureau of
Energy Efficiency (BEE) and first cycle will run over 2012–2015 for eight sectors covering 478
designated consumers. PAT is a national initiative in India, in addition to CDM implemented by
UNFCC on climate change. [4]
International Approach: The PAT mechanism is a unique scheme that, perhaps, does not have
any international benchmark. However, while designing the scheme, a survey of best practices and
lessons learnt from several international schemes was undertaken.
1.
European Union Emission Trading Scheme (EU ETS) - The Scheme is one of the EU’s
key measures for delivering its commitments under the Kyoto Protocol and for delivering
its objective of demonstrating leadership in reducing emissions of greenhouse gases.
2.
Climate Change Agreements (CCAs) - CCAs are voluntary mechanisms that encourage
energy efficiency in energy intensive industries in the UK.
3.
CRC Energy Efficiency Scheme (CRC) - It has been designed to raise awareness in large
organisations and encourage changes in behaviour and infrastructure.
4.
Tradable White Certificates (TWCs) - Under this mechanism, producers, suppliers or
distributors of electricity, gas and oil are required to undertake energy efficiency measures
for the final user.
5.
United Kingdom Emission Trading Scheme (UK ETS) - The scheme aimed to secure
cost-effective emissions reductions and give UK companies early experience of emissions
trading.
6.
UK Renewables Obligation (RO) - It is the Government’s main policy mechanism for
incentivising renewable electricity in the UK.
7.
Regional Greenhouse Gas Initiative (RGGI) - It is a mandatory scheme in the United
States aiming to reduce greenhouse gas emissions.
8.
New South Wales Greenhouse Gas Abatement Scheme (NSW GGAS) - It aims to
reduce greenhouse gas emissions associated with the production and use of electricity.
[4]Shakti Sustainable Foundation, Report on Capabilities and Requirements of State Designated Agencies in India, 2013,
retrieved from http://shaktifoundation.in/cms/UploadedImages/sda%20final%20report.pdf as on 1-4-2014
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An Assessment of Perform Achieve and Trade Mechanism - A Case Study of Industries in District Ropar,
Punjab
9.
Chicago Climate Exchange (CCX) - CCX is a voluntary, legally binding greenhouse gas
reduction and trading system for emission sources and offset projects in North America
and Brazil.
10.
US Acid Rain Programme (ARP) – It aims to reduce overall atmospheric levels of
sulphur dioxide and nitrogen oxides, which cause acid rain.
11.
China's Top-1000 Energy-Consuming Enterprises Program - It targets energy
efficiency improvements in the 1,000 largest enterprises that together consume one-third of
all China's primary energy. [5]
The industry sector is the largest user of commercial segment, with necessary technology tie-ups,
where energy in India, accounting for 42% of the country's desirable, would be established. [6] To
enhance energy efficiency in industries, the Perform, Achieve and Trade (PAT) mechanism is
created with the basic green energy concept similar to the Energy Efficiency Portfolio Standard
mechanisms in United State, Tradable Green certificates in Europe and similar programmes in
other countries.
The Energy Conservation Act empowers the central government to notify the DCs based on the
annual energy consumption of a plant by comparing with the threshold limit prescribed for the
sector. The Government, in March 2007 notified units in nine industrial sectors, namely
aluminium, cement, chlor-alkali, fertilizers, iron and steel pulp and paper, railways, textiles and
thermal power plants, as Designated Consumers (DCs). The PAT scheme is currently applicable
for eight designated sectors as listed above, with railways being excluded in the first instance. As
per the Energy Conservation Act, it is mandatory for all the designated energy consumers to get
energy audit conducted by an Accredited/ Designated Energy Auditor (DENA) and to designate or
appoint an Energy Manager. BEE has taken up the challenge of creating a cadre of professionally
qualified energy managers with expertise in energy management, project management, financing
and implementation of energy efficiency projects, and policy analysis. The PAT framework
includes the methodology for setting the Specific Energy Consumption (SEC) target for each
Designated Consumer (DC) and its target for SEC reduction. [7] The PAT mechanism is also
[5]Bureau of Energy Efficiency, PAT Consultation Document,2011, retrieved from
http://beeindia.in/NMEEE/PAT%20Consultation%20Document_10Jan2011.pdf as on 7-4-2014
[6]Government of India, National Action Plan on Climate Change, retrieved from
http://pmindia.gov.in/climate_change_english.pdf as on 17-2-2014
[7]Kumar Rajesh, Agarwala Arun, Energy certificates REC and PAT sustenance to energy model for India, Renewable
and Sustainable Energy Reviews 21 (2013), 315–323, retrieved from http://ac.els-cdn.com/S1364032113000270/1-s2.0-
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Ravneet Kaur
designed to promote enhanced energy efficient technology in industry to achieve their SEC
improvement target in a cost-effective manner. The additional certified energy savings in the form
of Energy Saving Certificates (ESCert) can be traded with other designated consumers who could
use these certificates to comply with their own Specific Energy Consumption reduction targets.
Penalty for noncompliance is Rs. 10 lakhs and is also linked to the value of non-compliance
measured in terms of the market value of tones of oil.[8]
Energy Saving Certificates (ESCert): An ESCert is an instrument issued by an authorized body
guaranteeing that a stipulated amount of energy savings has been achieved and has entered the
Indian Energy Efficiency mandate under the PAT scheme. Each certificate is a unique tradable
commodity that gives property right over additional units of intangible bundle of societal and
environmental benefits created by energy saved over and above the baseline level. ESCerts provide
a platform for parties to trade the attributes of energy savings.
An ESCert can be represented in units of electricity saving such as 1 MWh5 (1 ESCert is issued for
1 MWh of energy saved over and above the set target). This is followed by the implementation of
the energy saving scheme by the DCs. The savings out of this scheme is measured on the basis of
the baseline energy requirement and the scheme is then is put through the process of third party
verification by designated energy auditors. [9] The BEE has also set up a registry and exchanges for
the trading of ESCert, creation of records for trading and cancellation of ESCert, to enable crosssectoral use of ESCerts. There will be different targets for subsequent PAT cycles. The SEC
reduction target will be progressively stringent in subsequent PAT cycles to keep pace with the
national energy efficiency mission. [10]
S1364032113000270-main.pdf?_tid=cf3b4284-c08d-11e3-b50c00000aab0f27&acdnat=1397120285_83958b79b43be28d6eb4648ec4e34c06 as on 7-4-2014
[8]Bureau of Energy Efficiency, PAT Consultation Document,2011, retrieved from
http://beeindia.in/NMEEE/PAT%20Consultation%20Document_10Jan2011.pdf as on 6-4-2014
[9]Bhattacharya Tanushree, Kapoor Richa, Energy saving instrument – ESCerts in India, Renewable and Sustainable
Energy Reviews, 16 (2012) 1311– 1316, retrieved from http://ac.els-cdn.com/S1364032111004850/1-s2.0S1364032111004850-main.pdf?_tid=9d2f5812-bfbf-11e3-ad7900000aacb35d&acdnat=1397031724_a624e3145ea15ab3a78cfa4aa1bd93ac as on 7-4-2014
[10]International Emission Trading Association, The World’s Carbon Markets: A Case Study Guide to Emissions
Trading,2013, retrieved from
http://www.ieta.org/assets/Reports/EmissionsTradingAroundTheWorld/edf_ieta_japan_case_study_september_2013.pdf
as on 7-4-2014
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An Assessment of Perform Achieve and Trade Mechanism - A Case Study of Industries in District Ropar,
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Fig 2 Timeline for Perform Achieve and Trade Scheme [11]
EC Act
2001
NAPCC
Sector Studies
Commenced
2008
First consultation
NMEE
workshop; consultation
period
continues through 2012
Baseline Data
Collection Begins
2009
Financial Outlay of over
US$40 Million approved
2010
2011
2012
2015
NMEEE approved by
Prime Minister’s Council
Energy Conservation Act
amended to allow trading
PAT scheme came into
effect, first compliance
on Climate Change
in ESCrs
begins (2012-2015)
Role of PEDA in PAT Scheme:The BEE has been engaged in building the capacity of the SDAs
in the implementation of the PAT scheme over the last few years. The key responsibilities of the
SDAs under amended EC Act include:
•
•
•
•
•
•
•
•
•
•
•
•
Updation and maintenance of list of Designated Consumers and ensure the submission of
energy return form by each DC every year.
Maintaining the list of Designated Energy Auditors (DENAs).
Develop a Market mechanism for ESCerts and promote transfer of knowledge in energy
efficiency.
Inspection of Designated Consumer for compliance to energy consumption norms and
standards and makes provisions for levying penalty for the defaulters.
Exchange of information among all stakeholders relating to ESCerts trading mechanism
through a central on-line integrated information system.
Enable tracking, monitoring and reporting energy reduction details.
Access information available on PAT NET to calculate and levy penalty on designated
consumers.
Provide information to BEE through PAD (PAT Assessment Document)
Gather, monitor and analyse data reported by DCs to identify any uneven aberrations in energy
savings so as to conduct on site audits.
Receive trading details and obligations from trading exchanges.
Obtain audit details conducted by DENAs through PAT NET.
Act as the body responsible for adjudicating matters related to penalizing the DCs for non
compliance. [12]
[11]Singh Neelam, Creating market support for energy efficiency: India’s Perform, Achieve And Trade
scheme, Climate and Development Knowledge Network, 2013,retrieved from http://cdkn.org/wpcontent/uploads/2013/01/India-PAT_InsideStory.pdf as on 2-4-2014
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Ravneet Kaur
So PEDA plays a significant role by creating a database for BEE, DENA, Energy Managers, DCs
and other stakeholders.
2. OBJECTIVE
PEDA has a total of 22 Designated Consumers in the State. In Ropar district there are four
industries which are chosen as Designated Consumers. They are Punjab Alkalies and Chemical
Ltd., National Fertilizer Limited, Ambuja Cement Limited and Guru Gobind Singh Super Thermal
Power Station. The main objective of paper is to analyse the contribution of PEDA in PAT scheme
and highlighting some loopholes of Govt. institutions while rendering their services under this
scheme while undertaking a study on industries situated in District Ropar. Firstly the primary audit
is done by DENAs appointed by central Government in consultation with BEE and simultaneously
energy audit is done by SDAs. In accordance with both audits DCs are chosen.
3. METHODOLOGY
The paper comprises both primary as well as secondary data. Primary data is collected by using
telephonic interview method and general discussion. It includes
1.
The officials of PEDA who are involved in PAT scheme
2.
The Energy Managers of industries chosen as Designated Consumers.
Secondary data is collected through annual reports and documents provided by PEDA.
4. FINDINGS
Table 1 A list of Designated Consumers of Ropar District and their Targets for the year 201213 to 2014-15 under the PAT Scheme
Sr.
No.
Designated
Consumers
Sector
Baseline energy consumption
norms and standards in metric
ton of oil equivalent
(TOE) per unit of product for the
baseline year (average of three
years).
Energy
consumption
norms
and
standards
in
metric ton of oil
equivalent (TOE)
per
unit
of
product for target
year.
[12]Shakti Sustainable Foundation, Report on Capabilities and Requirements of State Designated Agencies in India,
2013, retrieved from http://shaktifoundation.in/cms/UploadedImages/sda%20final%20report.pdf as on 1-4-2014
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An Assessment of Perform Achieve and Trade Mechanism - A Case Study of Industries in District Ropar,
Punjab
Name
1.
2.
3.
4.
Punjab Alkalis and
Chemical Ltd.
National Fertilizers
Limited
Ambuja
Cement
Limited
Guru Gobind Singh
Super
Thermal
Power Station
Chlor
Alkali
Fertilizer
Specific energy
consumption
(TOE/Ton of
Product)
0.319
Product
Output
(Ton)
88, 959
Specific energy
consumption
(TOE/Ton
of
Product)
0.299
0.704
489008
0.528
Cement
0.0201
2800401.57
0.0189
Thermal
Power
Plant
0.2922
9008
2830
(Source- Punjab Energy Development Agency Documents)
The role of PEDA in PAT scheme is very limited. BEE is leading the process with in-house and
external technical experts and auditing agencies. PEDA is not assigned with a large amount of
tasks as defined in the PAT consultation document. PEDA participates little in the responsibility of
choosing the Designated Consumers and no participation is authorized in appointing DENAs and
Energy Managers. It is not empowered to monitor and evaluate the reports send by DCs by doing
field visits to industries in the form of follow-ups to analyze the performance and working of
Industries. There is no trained staff in PEDA specific to PAT to engage in activities like providing
proper and adequate training to Designated Consumers regarding Energy efficient appliances and
the methods to achieve their targets as assigned by Govt. of India. The workshops conducted by
PEDA in consultation with BEE for Designated Consumers does not provide in-depth knowledge
to consumers regarding saving of energy and the procedure to prepare correct energy reports in the
form of FORM-1. PEDA is just playing a role of bridge between Designated Consumers and BEE.
5. CONCLUSION AND SUGGESTIONS
SDAs are very familiar with renewable energy, technologies, policies, and implementation at the
state level and they play a significant role in regulating Energy Conservation activities in the state.
PEDA has pool of technically qualified manpower, but has shortage of staff trained in Energy
Efficiency technologies, policies, PAT process, industry processes for Designated Consumers and
related areas. Monitoring the PAT scheme and ensuring the correctness of certificates to be issued
is a complex and challenging task. So BEE should involve PEDA much in displaying and
exchanging information related to the performance of Designated Consumers. In case of
verifications associated with penalties and issue of more ESCerts, BEE should empower PEDA to
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Ravneet Kaur
timely intervene with their compiled energy saving reports as prepared independently by them.
BEE should initiate half yearly meetings with all SDAs to communicate regarding the progress of
Designated Consumers and to discuss the further matters to achieve the targets of Designated
Consumers. PEDA can improve its efficiency in PAT scheme by initiating more interactive
sessions with Energy Managers and Energy Auditors of Designated Consumers. There is thus a
need for improved co-ordination between these agencies for the smooth and effective
implementation of the PAT scheme.
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Migration of Landfill Gas From the Soil
Adjacent to the Landfill
M. J. Khalil1, Rimzhim Gupta2, Kartik Sharma3
Department of Chemical Engineering, Aligarh Muslim University, Aligarh,202002,INDIA
ABSTRACT
The migration of LFG is a significant issue in the field of solid waste management. This paper
analyses various factors which are responsible for the migration along with its controlling
techniques. The emission of migration of LFG potentially have adverse effect on environment
including fire and explosion, health risk, odour nuisance, vegetation distress and groundwater
contamination. Methane component of the LFG is a potent greenhouse gas, which has been
linked to global warming and climate change. Under normal conditions, gases produced in soils
are released to the atmosphere by means of molecular diffusion. In the case of an active landfill,
the internal pressure is usually greater than atmospheric pressure and both convective flow and
diffusion will contribute to the release of LFG. The biochemical reactions that produce the gas
typically continue long after a landfill is capped. Both gases CH4 and CO2 contribute to global
climate change therefore gas collection systems are recommended and sometimes required at
landfills. Control systems can be classified as active or passive. The controlling techniques by
which the LFG migration is controlled has also been discussed. Biofilters are not yet a proven
technology for LFG treatment, however this emerging technique may become an option in the
future.
Keywords: LFG, Gas Migration, Active control system, Passive control system, Biofilters
1. INTRODUCTION
Solid waste mass is increasing day by day as the population is increasing. So there is a need to
manage the waste mass wisely without affecting the environmental substances (water, air, soil).
There may be four ways to treat the solid waste mass. Composting, incineration and landfilling and
recycling.
Sanitary landfills are widely used for the disposal of solid waste. Landfills can result in serious
environmental problems if not properly managed and operated. The most common problem
associated with landfill operations is the generation of leachate and gases. And the other major
problem is migration of those gases which are toxic in nature or at particular temperature, pressure
and volume conditions they come under explosive limits. For example: methane is explosive when
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M. J. Khalil, Rimzhim Gupta, Kartik Sharma
its volumetric concentration attains 5% to 15% (50,000 to 150,000 ppm) in an air mixture [8].
Landfill gas is produced after various phases of mechanism. First when solid waste is dumped in
the landfill, the microorganisms in presence of oxygen, which is present in the void space, gives
rise to aerobic decomposition during which biodegradable organic materials react quickly with
oxygen to form carbon dioxide, water, and other by-products (e.g. bacterial cells) [1]. Carbon
dioxide is produced in approximate molar equivalents to the oxygen consumed. Oxygen depletion
within the landfill marks the onset of the anaerobic decomposition phase. Although a landfill
ecosystem undergoes an initial short aerobic decomposition phase, the subsequent anaerobic phase
is the dominant phase in its age and the more important one from the perspective of gas formation.
Then after going through hydrolysis, acidogenesis, acetogenesis and methanogenesis the landfill
gas is produces having approximately 50% CH4 and 50% CO2.
Each stage is having its own significance and its different products. In acidogenesis phase, all the
leachate characteristics (COD, VFA, Metal content Fe,Zn) are at their peak except pH, because of
presence of high volatile fatty acids the pH is lowest in this phase. Small amounts of non-methane
organic compounds (NMOCs) and trace amounts of inorganic compounds comprise less than 1%
of the mixture. Heat is also generated during the anaerobic degradation, but at a smaller rate than
during the initial aerobic phase. In reality biochemical reactions involved in the mechanism of
landfill gas do not occur in a homogeneous manner. Due to local variations in waste composition,
moisture content, vicinity of inhibitors and nutrients and temperature, the reaction rates might
differ significantly from place to place and all the phases might occur simultaneously through the
landfill.
2. CAUSES OF MIGRATION
Gases always follow the path of least resistance. So, Landfill gas migrates vertically or laterally, if
the gas is being transported under the effect of gravity then the migration would be vertical.
Generally vertical migration enhances the ground water contamination and if the gas is covering
some meter distance laterally and then exposing to the atmosphere, which may be lead to the
hazards and explosion due the drastic increase in pressure. In lateral migration case, Although most
of the methane escapes to the atmosphere, both CH4 and CO2 have been found at concentrations up
to 40 percent each, at lateral distances of up to 400 ft. from the edges of unlined landfills. Methane
concentrations over 5 percent have been measured at a distance of 1000 ft. The movement of
landfill gas in unconsolidated soils is controlled by several mechanisms [11]. When gas released to
the atmosphere, landfill gas represents a threat to the environment, because both methane and
carbon dioxide are greenhouse gases. Also, several of the produced organic compounds present
health hazards. The other important reason to control the migration of gases is that methane is also
a rich source of energy.
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Migration of Landfill Gas From the Soil Adjacent to the Landfill
•
•
Although liners and leachate collection systems minimize leakage, liners can fail and leachate
collection systems may not collect all the leachate that escapes from a landfill. Leachate
collection systems require maintenance of pipes, and pipes can fail because they crack,
collapse, or fill with sediment.
Upon the completion of a landfill, the waste is covered by a low permeability capping system
which limits the water infiltration and minimizes the leachate generation, the cover also hinders
the landfill gas emission to the atmosphere but the lateral migration of the gas can be enhanced
if not properly treated. Lateral migration of methane is also enhanced if higher-permeability
soils such as sand and gravel, or fractured till are present adjacent to the landfill.
3. RESPONSIBLE FUNDAMENTAL PROCESSES
Migration occurs via two ways either by diffusive transport or advective transport. Diffusive
transport is caused by the variation in gas concentrations in the soil because the concentration of
landfill gas in atmosphere is very low so a gradient develops. Advective transport is caused by the
pressure gradient. The pressure inside the landfill can be quite high and can result in a large
pressure gradient. Changes in barometric pressure can change the pressure gradient. The gas
pressure and composition vary during the active life of the landfill. Methane and Carbon dioxide
generation leads to increase in pressure and corresponding partial pressures. These changes create
pressure gradients leading to gas advection, as well as concentration gradients that lead to gas
diffusion [10].
4. INFLUENCING FACTORS
The primary factors that influence the distance gas migrates from the landfill are the permeability
of the soil adjacent to the landfill, and the type of ground surface cover around the landfill.
•
•
•
•
Generally, the greater the permeability of the soil, the greater the possible gas migration
distance. As methane is lighter than air, it tends to rise and escape preferentially through the
landfill cover, whenever the cover is sufficiently permeable [9].
Heat generation also influences gas migration because of its effect on the thermodynamic
properties of the fluids [9].
Generally, increases in ambient temperature result in increased rates of gas migration, as it
enhances the diffusion of the gas through the soil. However, phenomena like snow cover or
frozen soil have a more profound effect on methane gas migration than the ambient
temperature itself.
The methane concentration can even be higher in very wet landfills due to a higher solubility of
carbon dioxide in water. In older landfills the production of landfill gas reduces and
atmospheric air can enter the landfill. The landfill gas can contain significant amounts of
nitrogen. And with the oxygen from the air methane can be oxidised. This results both in a
reduction of the methane percentage and an increase of the carbon dioxide percentage.
Therefore the quality of landfill gas in older landfills can vary considerably. Landfill gas can
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M. J. Khalil, Rimzhim Gupta, Kartik Sharma
also contain traces of other ((poly) aromatic) hydrocarbons, halogenated hydrocarbons and
sulphur compounds.
Modelling of Migration of Landfill Gas
Gases are transported by a buried source by two mechanisms:
Convection(advection ) due to pressure gradient
Diffusion due to concentration gradient
The migration under such conditions is mathematically represented by mass conservation equation
of diffusing species [7]:
¬
¬D
=
¬
¬
®¯ ¬
­q‚
Ž − eqG
¬q
¬‚
¬q
(1)
The volume averaged velocity rather than the mass averaged velocity is used because the fluid
system is inhomogeneous. The relationship between the two velocities is given by:
®¯ ¬°
¬‚
eqG = eq∗ + ­q‚
(2)
The mass averaged velocity is obtained from the mass conservation of gas mixture and Darcy’s law
¬°
¬D
¬
+ ¬q ,ªeq∗ ) = 0
(3)
¬´
±²
eq∗ = − }³
¬‚
(4)
Upward Migration of Landfill Gas: The principal gases, methane and carbon dioxide, can be
released through the landfill cover into the atmosphere by convection and diffusion. The diffusive
flow through the cover can be estimated by
n = ­ ∝/ ,µ¶· ¸µ¹±ºº )
»
(5)
Typical values for the coefficient of diffusion for methane and carbon dioxide are 0.20 cm2/s (18.6
ft2/d) and 0.13 cm2/s (14.1 ft2/d), respectively (Lang and Tchobanoglous, 1989). It is also common
to assume dry soil conditions, thus αgas =α. Assuming dry soil conditions introduces a safety factor
in that any infiltration of water into the landfill cover will reduce the gasfilled porosity and thus
reduce the vapor flux from the landfill. Typically, porosity values for different types of clay vary
from 0.010 to 0.30 [10].
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Migration of Landfill Gas From the Soil Adjacent to the Landfill
Downward Migration of Landfill Gas: Ultimately, CO2, because of its density, can accumulate in
the bottom of a landfill. If a clay or soil liner is used, the carbon dioxide can move from their
downward primarily by diffusive transport through the liner and the underlying formation until it
reaches the groundwater (note that the movement of carbon dioxide can be limited with the use of a
geomembrane liner). Because carbon dioxide is readily soluble in water, it usually lowers the pH,
which in turn can increase the hardness and mineral con-tent of the groundwater through
solubilisation [10].
5. LANDFILL GAS MIGRATION CONTROL
When landfills have reached the maximum amount of waste they can hold, several feet of cover
material are placed over the landfill mass. Gas collection wells are then installed throughout the
capped landfill. These wells are made of perforated pipes which give the gas an easy path to move
vertically to the surface rather than laterally (outward) toward off-site locations (e.g., buildings). As
the gases enter these wells they are either vented into the outdoor air, passed through a flame and
broken down by burning, passed through a filter, or used in an energy recovery program. Landfill
gas vents need to be kept drained and clear of obstructions such as snow and debris. Older landfills
and smaller dumps may not have gas control measures.
Landfill gas components may be absorbed onto by soil particles, transferred to water and oxidized
by methane consuming bacteria (methanotropic). This phenomena may reduce emissions and
migration of landfill gas from the site [4].
6. DETECTION OF THE LANDFILL GAS MIGRATION
The probe is installed by boring a hole into the ground to at least the same depth as the landfill. A
perforated pipe is placed into the hole and the space between the original soil, and the pipe is filled
with sand. Clay is packed around the pipe near the ground surface to pre-vent air from leaking into
the probe. Two types of measurements are conducted. Gas pressure is measured with a gauge or
manometer. A positive reading indicates that LFG is moving past the probe because of pressure
built up within the landfill.
Negative pressure typically results when a probe is installed near a LFG recovery well. The
concentration of methane in the soil atmosphere also is measured with a calibrated meter. A
concentration greater than 5 percent methane indicates migration may have dangerous
consequences if the gas enters a building. Because migration patterns and methane concentrations
change rapidly, frequent measurements are required to obtain an accurate picture of the gas
migration pattern. At sites where a high degree of concern about gas migration endangering
residences exists, daily measurements should be conducted until the crisis has passed [6].
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M. J. Khalil, Rimzhim Gupta, Kartik Sharma
7. GAS VENTS AND RECOVERY SYSTEMS
Passive vents and active gas pumping systems are used to control LFG migration.
Passive vent system: Passive systems rely on natural pressure and convection mechanisms to vent
the gas into the atmosphere. Gas venting pipes, installed within the landfill and vented into the
atmosphere have been used to allow gas from a landfill’s interior regions to escape. These natural
vents may be equipped with flares to burn-off the gas and to prevent odours. Passive vents do not
always effectively remove LFG from under the cover. This causes vegetative stress and
accompanying erosion problems on the cover. Passive vent failure generally is attributed to an
insufficient pressure gradient within the landfill to push the gas to the venting device. Passive vents
also can be problematic when alternating periods of high and low barometric pressure cause
atmospheric air to enter the landfill when barometric pressure rises. Passive systems are not
considered reliable enough to be the sole means of protection in areas where there is a significant
risk of methane accumulation in buildings [4].
Passive Gas Collection System
Active Gas Collection System
Active Gas Recovery Systems: Active gas collection systems remove LFG under a vacuum from
the landfill or the surrounding soil formation, with the gas literally being pumped out of the ground
[4]. Active gas collection systems include vacuums or pumps to move gas out of the landfill and
piping that connects the collection wells to the vacuum. Vacuums or pumps pull gas from the
landfill by creating low pressure within the gas collection wells. The low pressure in the wells
creates a preferred migration pathway for the landfill gas. The size, type, and number of vacuums
required in an active system to pull the gas from the land-fill depend on the amount of gas being
produced.
8. FLARE SYSTEM
A common method of treatment for landfill gases is thermal destruction, in which the methane and
any other trace gases (including VOCs) are combusted in the presence of oxygen to CO2, sulfur
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Migration of Landfill Gas From the Soil Adjacent to the Landfill
dioxide (SO2), oxides of nitrogen, and other related gases. The thermal destruction of landfill gases
is usually accomplished in a specially designed flaring facility [3]. A typical requirement might be
a minimum combustion temperature of 1500°F and a residence time of 0.3 to 0.5s, along with a
variety of controls and instrumentation in the flaring station. Where the landfill gas contains less
than 15 percent methane, supplemental natural gas or propane may need to be supplied to the flare
to sustain combustion. Installation of a carbon filter is an alternative approach to flaring for control
of VOCs [10].
9. FUTURE RECOMMENDATION
Biofilters: Boifiltration is an air pollution control technology in which we utilize the activity of
microorganism for the biologically degradation of pollutants [4]. A biofilter is essentially a packed
bed reactor containing microorganism, growing in an active biofilm. This biofilm is formed on the
surface of the biofilter bed material usually consist of some type of compost, peat or soil material.
The contaminated vent stream having LFG passes through the filter medium where the pollutant
(trace components) is transferred from the vapour phase to the biofilm and degraded by
microorganism. But there might be a problem in biofilters which is biofauling. Biofouling is a
process defined as the undesirable accumulation of microorganisms, their products and deposits
including minerals and organic materials, and macro-organisms on substrate surfaces [2].
10. NOMENCLATURE
C=C(Xi,t)=ρα/ρα0 = non dimensional concentration of α species
ρα= mass densities of α species
ρα0=value of ρα at the source
xi=Cartesian frame of reference
®¯
­q‚ = tensor of diffusion coefficients (α species diffusing into β species) in soil
eqG =volume averaged velocity
eq∗= mass averaged velocity
ρ= mass density of the fluid mixture
Kij = tensor of intrinsic permeability
n= porosity of soil
µ= absolute viscosity of mixture of gases
p=scalar pressure field
NA= gas flux of compound A, g/cm2⋅ s (lb-mol/ft2⋅ d)
D = effective diffusion coefficient, cm2/s (ft2/d)
α=total porosity, cm3/cm3 (ft3/ft3)
CAatm= concentration of compound A at the surface of the landfill cover, g/cm3 (lb-mol/ft3)
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M. J. Khalil, Rimzhim Gupta, Kartik Sharma
CAfill= concentration of compound A at bottom of the landfill cover, g/cm3 (lb-mol/ft3)
L = depth of the landfill cover, cm (ft)
REFERENCES
[1] Barlaz MA, Ham RK., Schaefer DM, “Microbial ,chemical and methane production characterstics of
anaerobically decomposed refuse with and without leachate recycling”. Waste Management & Research
10 257-267
[2] 1992. DongGu J.,”Microbiologicaldeteriorationanddegradationofsyntheticpolymeric materials: recent
research advances”, International Biodeterioration & Biodegradation ELSEVIER 52 (2003) 69–91.
[3] Landfill Gas Control Measures , 2001 p(53-64)
[4] Landfill Gas Management Plan Revision 001 May 2010 Transpacific Cleanaway Tullamarine.
[5] Lang, R. J., and G. Tchobanoglous (1989) Movement of Gases in Municipal Solid Waste
Landfills:Appendix A, Modelling the Movement of Gases in Municipal Solid Waste Landfills,prepared
for the California Waste Management Board, Department of Civil Engineering, University of California,
Davis, Davis, CA.
[6] Leary P.O., Walsh P., Landfill Gas Movement, Control and Energy Recovery, March 2002, p 48-54
[7] Mohsen M.F.N., Farquhar G.J., Kauwen N.,Gas migration and vent design at landfill sites, water, air and
soil pollution 13(1980),79-97
[8] Nastev M., Therrien R., Lefebvre R., Gelinas P., Gas production and migration in landfills and
geological materials, Journal of Contaminant Hydrology ELSEVIER 52 2001 187–211.
[9] Poulsen T.G., Christophersen M., Moldrup P., and Kjeldsen P., Modeling of Lateral gas transport in soil
adjacent to old Landfill, Journal of Environmental Engineering, 2001.127:145-153.
[10] Tchobanoglous G., Kreith F., “Handbook of solid waste management”, second edition, McGRAW-HILL
Publication 14.1-14.81.
[11] Williams, G. M., R. S. Ward, and D. J. Noy (1999), “Dynamics of Landfill Gas Migration in
Unsolidated Sands,”Waste Management & Research, vol. 17.
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Self – Energy Generating Cookstove
Risha Mal1, Rajendra Prasad2, V.K. Vijay3, Amit Ranjan Verma4, Ratneesh Tiwari5
Centre for Rural Development and Technology
Indian Institute of Technology, Hauz-Khas, New Delhi, India
ABSTRACT
This paper emphasizes on a sustainable way of utilizing waste thermal energy produced from the
cookstove used in rural areas and converting directly to useful electrical energy. The process of
converting thermal energy into electricity is achieved by using a thermoelectric generator (TEG)
module. A difference in temperature on both the sides of TEG proportionally produces
electricity. An appropriate TEG module is selected with reference to is temperature tolerance
and various electrical parameters. The power attained from the TEG can be utilized for various
purposes like running a fan to improve the efficiency of cookstove and provide sufficient air
inside the combustion chamber to increase the air-fuel ratio and to achieve complete
combustion, charge battery of mobile phones, run a small radio, lighting and many other
applications. The fan running by a TEG serves dual purposes of cooling one side of the TEG (so
that the temperature difference is maintained) and providing air for combustion of the fuel to
make cooking clean without harmful emissions. The power generated from the chosen TEG is 3
Watt which powers a 3.2 Volt fan and charge batteries.
Keywords: Thermoelectric generator (TEG), cookstove, waste heat.
1. INTRODUCTION
Cooking is one of the most essential parts of daily household practices. The mode of device for
cooking varies from rural to urban areas. The Rural and Urban population in India was last reported
at 69.90 and 30.1 (% of total population) respectively in 2010, according to a World Bank report
published in 2012. The growth rate of population in rural and urban areas was 12.18% and 31.80%
respectively. About 65 % of the population in urban area use LPG as cooking fuel compared to
62.5 % of the rural household use firewood as cooking fuel. Using firewood, dung cake, crop
residue etc. in traditional cookstove results in lower efficiency, high emissions of air pollutants and
smoke. The emissions from the traditional cookstove are very hazardous which subsequently lead
to many harmful diseases like respiratory disease, eye irritation, premature birth, death of fetus and
many more. Cookstoves with a fan attached to it gives a more cleaner cooking since it increases the
air-to fuel ratio and enhances combustion. Most of the rural villages are still not electrified, so to
run a fan for the cookstove needs power from grid. A solution to run a fan off-grid is to integrate a
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Risha Mal, Rajendra Prasad, V.K. Vijay, Amit Ranjan Verma, Ratneesh Tiwari
thermoelectric generator and utilize the waste heat of the cookstove to directly convert it into
electricity.
Fig 1: Use of different fuels for cooking in urban and rural India respectively from census
2011.
The principle behind TEG is to convert waste heat as heat source into electricity, which is regarded
as totally green technology since the input energy is totally free of cost, and the output of the of the
TEG module is of high importance due to its power generating feature and making the cookstove
economically viable. On the advent of semiconductor material science the thermoelectric
generation practical applications got high emphasis of conversion of waste heat into electricity. The
features like reliability and ruggedness of semiconductor material that came from solid state
function has made this technology more viable and useful. The advantages of TEG integrated with
cookstove are that the flame heat from the cookstove serves as input to the TEG and no extra
energy is required, the TEG module is incorporated in the wall of the cookstove, unlike solar panel
it do not require external electric link. The module is used to charge battery and run equipments,
the TEG have no moving parts hence the operation is silent, TEG is very rugged and almost
maintenance free; whole module is placed indoor and no moving parts only battery needs
replacement when exhausted or can be recharged with module power continuously, TEG starts
working as the cookstove is set on fire irrespective of day and night, windy or rainy weather unlike
solar panels. Rechargeable batteries serve the purpose and need not be oversized batteries as used
in solar panels to store energy.
2. THERMOELECTRIC GENERATION
TEG Fundamentals
In 1821, Thomas J. Seebeck discovered that a potential difference could be produced by a circuit
made from two dissimilar wires when one of the junctions was heated. This is called Seebeck
effect. The emf is proportional to the temperature difference. The potential difference, ½ = ¾¿À,
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Self – Energy Generating Cookstove
where, ¿À = ÀÁ − À and α is the Seebeck coefficient or thermopower expressed in ý/Ä and the
sign of α is positive if emf tends to drive an electric current through wire A from the hot to cold
junction. The components of thermoelectric modules comprise of two different semiconductor
materials also known as Seebeck cells. TEG exhibits Seebeck effect for conversion of heat energy
into electricity as shown in fig. 2. The TEG module has many semiconductors connected
electrically in series to elevate the resulting voltage and due to the temperature difference between
the walls of the plate energy is captured from thermally excited electrons.
Fig. 2: Seebeck cells arrangement in a module.
The components of thermoelectric modules comprise of two different semiconductor materials also
known as Seebeck cells. The legs of the n and p-semiconductors are connected thermally in parallel
and electrically in series. As shown in above fig 2.Two ceramic wafers are placed in both faces of
the TEG to provide insulation. Thermal grease (heat conductive paste) is applied to attach the
wafers. Thermal Grease has higher thermal conductivity and is considered to be of a higher quality
and include high performance levels during long periods of time, the ability to withstand higher
temperatures and lower vaporization potential. The function of the semiconductor device is that
when heat flows through the module, the N-type material have highly negative charges i.e. excess
of electrons and the P-type material has more positively charged ions i.e. excess of holes which
results in electric flow of current. Most of them are alloys based on bismuth integrated with
materials like tellurium, antimony and selenium which are generally operated in low temperatures
to around 450K to 1300 K. The commercially available TEG for ambient air application and with
reasonable price, is Bismuth Telluride ÅÆÇ ÀÈÉ . The efficiency of TEG is the function of
temperature; it is called ‘goodness factor’ or ‘figure-of-merit’ of the thermocouple material Ê =
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Risha Mal, Rajendra Prasad, V.K. Vijay, Amit Ranjan Verma, Ratneesh Tiwari
¾Ç Ë
,
Ì
where Z is the electrical power factor, α, the Seebeck coefficient, σ the electrical conductivity
and k is the total thermal conductivity. The FOM is considered as a dimensionless form, ZT where
T is absolute temperature. The highest FOM for bismuth tellurium fabricated from p- and nthermocouple is recorded around 2.0x10¯ ³ K¯ ¹.
Fig. 3: Figure-of-Merit of a selection of materials [9]
3. RESULTS
Mostly cooking devices use fire as source for cooking. Hence, fire liberates heat which can be
utilized further to convert into useful energy. The TEG converts heat energy directly to electrical
energy. The TEGs were acquired from Hi-Z Technology. Two types of TEGs were acquired
namely HZ-14 and HZ-9 of 14 W and 9 W resp. The performances of the two TEGs were verified
by measuring the hot and the cold side of the TEG with thermocouples. The open circuit voltage is
measured across the terminal of the TEG and the current is measured with a current sensing
resistance if 0.005Ω in series with the TEG. The hot side of the TEG is placed on a 1 cm thick
aluminium plate. The cold side was mounted by a 16cm x 11cm x 7cm parallel plate aluminium
sink. A 5V 0.32 A fan was mounted on top of the sink. The air of the fan is also used to feed inside
the combustion chamber to increase the air to fuel ratio.The hot side was maintained with a
constant continuous 230˚C on the hot plate. Fig 4 shows the integration of TEG with the prototype
stove.
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Self – Energy Generating Cookstove
Fig 4. TEG integrated cookstove prototype
The performance of HZ-14 and HZ-9 is illustrated by graph 1(a) and graph 1 (b).
10
9
8
7
6
5
4
3
2
1
0
16
V oc
14
12
V load
10
Current (A)
8
Power (W)
6
4
2
0
200
180
160
140
120
100
Temperature differenc e (˚C)
80
60
40
V oc
V load
Current (A)
Power (W)
200 180 160 140 120 100 80
60
40
Temperature difference (˚C)
Graph 1: Relation of open circuit voltage, load voltage, current and power with respect to
temperature difference on both the sides of (a) HZ-14 (b) HZ-9.
The graph 1(a) of HZ-14 shows that the power output of the module is as high as 14 W. This is due
to high current output of nearly 8 A but the open circuit voltage is only 3.5 V and load voltage (at
matched load) is 1.5 V. Due to low voltage output DC-DC boost converter which can work from
millivolts to volts is required because it cannot be expected that the TEG always produces constant
∆T. The ∆T is deviates due to joules heating which tent to saturate the cold side temperature with
the hot side temperature. Therefore it results to mostly low power output for most of the time. The
cost of the HZ-14 is also high of about $85/module and $40/10000 module. Due to these
limitations of HZ-14, a HZ-9 module is chosen for the application. The graph 1(b) shows that the
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Risha Mal, Rajendra Prasad, V.K. Vijay, Amit Ranjan Verma, Ratneesh Tiwari
power output of HZ-9 is lower than HZ-14 but the open circuit voltage of HZ-9 is 6.9 V and load
voltage (at matched load) is nearly 3 V, hence it is reliable and easy to boost 3 V load voltage. The
cost of the HZ-9 is $45/module and $20/10000 module which is cheaper than HZ-14.
4. CONCLUSION
The TEG HZ-9 is chosen for the required application. The heat from the cookstove is utilized by
the TEG to directly convert heat into electricity. The power generated from the TEG is about 3 W.
The power output is required to run a small DC brushless fan which cools the cold side of TEG and
directs the air to the combustion chamber to improve combustion. The generated voltage is boosted
upto 5.2 V by a DC-DC boost converter and charges a mobile phone and glow LED lights. The
technology is viable for rural household where homes are not connected to grid.
REFERENCES
[1] WHO. Fact sheet No. 292: indoor air pollution and health; 2011.
[2] WHO. Global health risks: mortality and burden of disease attributable to selected major risks; 2009.
[3] Killander A, Bass JC. A stove-top generator for cold areas. In: Proceedings of the15th international
conference on thermoelectrics; 1996 Mar 26–29; New York, USA. New York: IEEE; 1996.
[4] Mastbergen D. Development and optimization of a stove-powered thermoelectric generator. Colorado
State University; ETHOS 2008.
[5] Champier D, Bedecarrats JP, Kousksou T, Rivaletto M, Strub F, Pignolet P. Study of a TE
(thermoelectric) generator incorporated in a multifunction wood stove. Energy 2011; 36:1518–26.
[6] Cedar, Jonathan M. (Scarsdale, NY, US), Drummond, Alexander H. (Austin, TX, US),"Portable
combustion device utilizing thermoelectrical generation",8297271.
[7] S.M. O’Shaughnessy, M.J. Deasy, C.E. Kinsella , J.V. Doyle , A.J. Robinson. Small scale electricity
generation from a portable biomass cookstove: Prototype design and preliminary results, Applied Energy
2012.
[8] David Michael Rowe , Thermoelectric waste heat recovery as a renewable energy source, International
Journal of Innovations in Energy Systems and Power, Vol. 1, no. 1, 2006
[9] H.J. Goldsmid. Applications of Thermoelectricity, Methuen Monograph, London, 1960.
[10] C.M. Bhandari, and D.M. Rowe, Thermal Conduction in Semiconductors, Wiley Eastern Ltd, 1988.
[11] Min G, Rowe DM. Peltier devices as generators, CRC Handbook of thermoelectrics Chap. 38. London:
CRC Press, 1995.
[12] Rowe DM. Evaluation of thermoelectric modules for power generation. J Power Sources 1998; 73: 193–
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[13] Rowe DM, Min G. Design theory of thermoelectric modules for electric power generation. IEEE ProcSci Meas Technol 1996; 143(6):351–6.
[14] R.Y. Nuwayhid, D.M. Rowe, G. Min. Low cost stove-top thermoelectric generator for regions with
unreliable electricity supply. Renewable Energy 28 (2003) 205–222.
[15] Risha Mal, Rajendra Prasad, V.K. Vijay. Renewable Energy from Biomass Cookstoves for Off Grid
Rural Areas. International Proceedings of chemical, biological and environmental engineering, vol 64.
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Low Cost Wind Turbines using Natural
Fiber and Glass Fiber Composites
Rohit Rai Dadhich¹, Ramniwas Bishnoi², Virwal Pritamkumar K.³, Sanjeev Kumar4
1,3,4
B. Tech (VIII) Sem., Department of mechanical engineering, NIMS University, Jaipur, 302021, India
2
Department of mechanical engineering, NIMS University, Jaipur 302021 India
ABSTRACT
India’s new emphasis on multi-dimensional development of non-conventional energy is an open
economy, for the growing energy need of 1000 million people may accelerate rapid utilization of
available non-conventional sources of the energy. The search for alternative energy sources and
technology that can help tap energy from sources hitherto not in use, has become especially
relevant in the wake of the energy crisis in the rural sector. In India, there are still eighty
thousand villages where darkness is not dispelled by electricity. Moreover, their remote location
hinders any access to a grid. There are several energy production methods and only one of them
or a hybrid system can be implemented by rural communities at an affordable investment. By
using contra-rotating turbine energy capturing efficiency can increase for power generation.i.e.
Electricity can be generated at low wind velocity as 3 meters per second. An effort has been
made to produce low cost wind turbine of 0.80 kilowatts for domestic utilization, 3 kilowatts for
farm management and pumping water for irrigation. This paper describes the techniques on
how cost effective turbine blades are manufactured using wood, natural and glass fiber
materials and cheap labor at remote sites. It also suggests the users of locally available material
for building towers and turbines to improve the economy and provide employment opportunity
for the folks of rural area. As details of experiments results showed this is cost effective
technology to manufacture wind turbine for rural area. If this non-renewable source of energy
integrates with a hybrid system, it will give permanent solution to the energy crisis.
Keywords: Contra-rotating turbines; wind velocity; hybrid system; power generation; wood;
natural and glass fiber materials.
1. INTRODUCTION
India’s new emphasis on multi-dimensional development of non-conventional energy is an open
economy, for the growing energy need of1000 million people may accelerate rapid utilization of
available non-conventional sources of the energy. The search for alternative energy sources and
technology that can help tap energy from sources hitherto not in use, has become especially
relevant in the wake of the energy crisis rural sector. Wind power is sustainable and clean source of
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energy[2]. In India, there are still eighty thousand villages where darkness is not dispelled by
electricity. Moreover their remote location hinders access to a grid. How to reduce the cost of wind
energy is a vital engineering challenge presented by the interlocking disciplines of aerodynamics,
structure, control, electrical conversion, and electronics.[6] There are several energy production
methods such as solar, wind biomass etc., only one of them or a hybrid system can be implemented
by rural communities at an affordable investment. The contra-rotating turbines capture more energy
from wind and provide more power. Wind tunnel tests on a prototype have shown that the design is
up to 40 per cent more efficient and far less noisy than a conventional single-rotor system. The
rotational direction and speed of the rotors are adjusted in response to the wind circumstance [4].
The benefits of having contra-rotating blades are well known. In fact, the design has existed for
more than a century and is widely used, for example, in propeller systems of submarine torpedoes
[3]. The concept is also used in airplane and boat propulsion systems, not to mention those remotecontrolled toy helicopters you can fly inside your house. Experiments to date also suggest that a
turbine with such a design can operate at lower wind speeds, allowing it to tap into a broader range
of wind resources. Electricity can be generated at wind velocity of magnitude of 3 meter per
second. To provide electrical power to rural community, an effort has been made to produce low
cost wind turbines of 0.80 kilowatts for domestic utilization, 3 kilowatts for farm management and
irrigation. Although, it is mean for rural area, but can be implemented in urban area, to provide
electricity in crisis as well as reduce load on grid. These systems can be installed on the flyovers,
bridges; reservoir sites and other sensitive area for lightening and operating vigilance devices. This
paper describes, how cost effective turbine blades are manufactured using wood, natural and glass
fiber materials and cheap labor at remote sites. Natural fibers are emerging as low cost, lightweight
and apparently environmentally superior alternatives to glass fibers in composites. It also suggests
the uses of locally available material for building towers for wind turbines for improving the
economy and increasing the employment opportunity in rural area. If this non- renewable source of
energy is integrated with highbred system, it will give permanent solution to energy crisis.
2. MATERIALS
For carrying out this experiment wood, light wood, wood dust, glass fiber and natural fiber like jute
is used but mainly concentrated on the natural fiber as the researches shows that natural fibers are
emerging as low cost, lightweight and apparently environmentally superior. Natural fiber
composites are likely to be environmentally superior composites in most cases for the following
reasons: (1) natural fiber production has lower environmental impacts compared to glass fiber
production; (2) natural fiber composites have higher fiber content for equivalent performance,
reducing more polluting base polymer content; (3) the light-weight natural fiber composites
improve fuel efficiency and reduce emissions in the use phase of the component, especially in auto
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applications; and (4) end of life incineration of natural fibers results in recovered energy and
carbon credits[1]. The structural properties of composite materials are derived primarily from the
fiber reinforcement. In a composite, the fiber contributes high tensile strength, enhancing properties
in the final part, such as strength and stiffness while minimizing weight.
3. METHOD
Since the experiment was for the light weight and low cost wind turbine, the manufacturing method
used in this experiment was resin transfer method (RTM) using mould techniques[2]. It is evident
that the shape of the mould is solely responsible for the geometry, tolerance and surface finish of
the parts made in the mould. Engineering design of the mould requires carefully considering a
range of factors, such as loads on mould surface, heating methods for resin curing, mould cavity
geometry, the sealing method between mould halves, mould closure and clamping, ejection of
mould and ejection of the worked part so this method was best way to design this type of wind
turbine blades .[5]
Fig. 1 Photograph of mould and tools
4. DEVELOPMENT
Fig. 2 Development Schedule
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5. WIND GENERATORS FOR RURAL COMMUNITIES
Small wind turbine (anything between 0.3 to 10 kilowatts) can keep countless homesteads, farmers,
remote communities, nomadic groups and installations, where grid may be lacking can provide
power, has a room for blade manufacturer such as cottage industry. Presently, available turbines are
mostly imported or have technological collaboration. To self sufficient and develop indigenous
wind turbines for following category machines are indigenously designed and fabricated using
simple techniques and local available materials and human skills. In India where high speed wind
is available, a single rotor turbine shall be used and low wind speed area a contra-rotating turbine
shall be suitable. Contra-rotating turbine shall be suitable. Contra-rotating wind turbine is shown in
figure-3. Coefficient of power factor for a contra-rotating turbine is given in figure-4.
Fig. 3 Contra Rotating Wind Turbine Fig. 4 Cp of Contra Rotating Turbine
6. MICRO TURBINE OF 0.80 KW POWER
A micro wind turbine of 0.8 kW rated power has been developed and is in operation for lightning
and battery charging. It can be installed on rooftop. A photograph of turbine is shown in figure 5.
The main parts are three bladed turbine, generator, controller and electric energy storage(battery).
The turbine blades are made of light weight wood, polyurethane foam. Jute and glass fiber and
polyester resin. Master of turbine is prepared by rapid manual technique. A close tool is made
using materials: wood, wood dust and glass fiber. A light weight structural core is formed using
wood and polyurethane foam. Layers of jute fabric and few layers of glass fabric laid on the core
and pressed in the close-tool. Blade surface is given a final touch. In this way, first batch of nine
blades are fabricated within weight variation range 10-50gms and centre of gravity variation range
of 0-20mm without balance. These blades show desired stiffness and are tested for 1.5 times of
rated wind velocity. Test set is made on roof top using Cadpa stone and FRP laminated bamboo as
a core to support the turbine. Blade fixing bracket is also fabricated using wooden tool.
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Fig. 5 Photograph of Rooftop Turbine
7. MINI TURBINE FOR IRRIGATION AND FARM MANAGEMENT OF 3 KW POWER
Mini turbine of 3.0 KW rated capacity has been designed and developed for irrigation and farm
management. The main parts are three bladed turbine, generator, controller and submersible pump.
The turbine blades are fabricated using light weight wood, polyurethane foam and glass fibers and
polyester resin. Master of turbine is prepared by rapid manual technique and close tool is
developed to get net-shape component. A light weight structural core is made using wood and
polyurethane foam. Designed layers of glass fabric is laid manually and pressed into the close tool.
Afterwards blade surface is given a final touch. In this way, first batch of nine blades are fabricated
within weight variation range 10-50gms and centre of gravity variation range of 0-25mm without
balance. These blade shows desired stiffness and tested for 1.5 times of rated velocity. It is installed
at test site at 18 feet height. Photograph of turbine is given in fig. 6. Structural core and tool are
given in fig. 7.
Fig. 6 Turbine 3 Kilowatts Power
Fig. 7 Structural Core
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8. CONCLUSION
This paper describes the need of indigenously developed cost effective technology to manufacture
wind turbine for rural area. Turbine blades and tools are developed using local available materials
and manpower. Micro -0.8 KW and Mini -3.0 KW turbines are in operation and under test for
various requirements. This will open an opportunity for employment as well as improve
productivity due availability of light to work more hours in a day. If this non- renewable source of
energy is integrated with highbred system. It will give permanent solution to energy crisis.
REFERENCES
[1] S. V. Joshi @Are natural fiber composites environmentally superior to glass fiber reinforced
composites? Received 6 January 2003; revised 28 August 2003; accepted 11 September 2003
[2] P. Santhana Kumar @Computational and Experimental Analysis of a Counter Rotating Wind Turbine
System, Journal of Scientific and Industrial Research Vol. 72, May 2013, PP 300-306
[3] Qiyue Song @Design, Fabrication, and Testing of a New Small Wind Turbine Blade by Qiyue Song
Guelph, Ontario, Canada © Qiyue Song, April, 2012
[4] Priyono Sutikno @Design and Blade Optimization of Contra Rotation Double Rotor Wind Turbine,
International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol: 11 No: 01
[5] Anthony Broad @Development of Vacuum Assisted Composites Manufacturing Technology for Wind
Turbine Blade Manufacture by Anthony Broad
[6] RiadhW. Y. [email protected] of a Contra rotating Small Wind Energy Converter, International
Scholarly Research Network, ISRN Mechanical Engineering, Volume 2011, Article ID 828739.
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Energy Security and Clean Use
Samarth Kohli1, Sanjeev Kumar2
1
MBA Oil & Gas, College of Management & Economic Studies
University of Petroleum & Energy Studies Dehradun, Uttarakhand, India
2
MBA Oil & Gas, College of Management & Economic Studies
University of Petroleum & Energy Studies Dehradun, Uttarakhand, India
ABSTRACT
As global demand for energy continues to rise especially in rapidly industrializing and
developing economies, energy security concerns become even more important. India’s economic
growth stands around 8 percent in the past decade, leading to 6.5 percent growth in the demand
for energy. Given the projected economic growth levels, energy demand is expected to continue
to rise; rising energy needs, in turn have drawn attention to the importance of energy security.
To provide solid economic growth and to maintain levels of economic performance, energy must
be readily available, affordable and be able to provide a reliable source of power without
vulnerability to long- or short-term disruptions. Energy security issue can be encounter by
accelerated development of energy infrastructure; human development index and technological
up-gradation are key areas for action. There are many drivers governing the secure supply of
energy such as Diversification of generation capacity, Prices, Levels of investment required,
Ease of transport, Concentration of suppliers, availability of skilled labor, Interconnection of
energy systems, Fuel substitution and Political threats. Now as we talk about the clean use of
energy Renewable energy provides reliable power supplies, fuel diversification, which enhances
energy security and lower risk of fuel spills while reducing the need for imported fuel and
conserve the nation’s natural resources. These resources can be used to produce electricity
without producing carbon dioxide (CO2), the leading cause of global climate change. In this
paper the challenges in achieving energy security and suggestions were carried out on
undertaking decentralized distribution inputs to achieve sustainability of programs. The findings
and recommendations in this paper are based on independent thinking of the author and do not
necessarily reflect views of commission or authority or any governing public or private body.
1. INTRODUCTION
As global demand for energy continues to rise especially in rapidly industrializing and developing
economies, energy security concerns become even more important. Currently, India is one of the
world’s fastest-growing economies. India’s real economic growth stands around 8 per cent in the
past decade, leading to 6.5 per cent growth in the demand for energy. Given the projected
economic growth levels energy demand is expected to continue to rise, rising energy needs, in turn
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have drawn attention to the importance of energy security. Energy security is ensured by
guaranteeing three factors – availability, accessibility and affordability of energy resources.
“We are energy secure when we can supply lifeline energy to all our citizens irrespective of their
ability to pay for it as well as meet their effective demand for safe and convenient energy to satisfy
their various needs at competitive prices, at all times and with a prescribed confidence level
considering shocks and disruptions that can be reasonably expected”
The rapid increase in economic activity has been accompanied by rising energy consumption.
Today, India is the fifth largest energy consumer in the world. While the world consumes 12000
million tonnes of oil equivalent (mtoe) of energy resources, India consumes 4.4% of the world total
(524.2 mtoe). Global consumption of primary commercial energy (coal, oil & natural gas, nuclear
and major hydro) has grown at a rate of 2.6% over the last decade. In India, the growth rate of
demand is around 6.8%, while the supply is expected to increase at a compounded annual growth
rate (CAGR) of only 1%. Coal, oil and natural gas are the most important sources of primary
energy in India, accounting for 52.9%, 29.6% and 10.6% respectively of the primary energy
consumption. Inadequate domestic supplies of these hydrocarbons are forcing the country to
increase its import bill. While the country remains highly dependent on oil imports, it is saddening
to note that supply of natural gas, which was expected to alleviate our energy security from the new
domestic fields remain well below projection. Of late, driven by accelerated capacity addition in
power generation and decline in domestic coal production, India’s imports of coal have risen for
the country having the world’s fourth-largest coal reserves. On the global front demand for
hydrocarbons is rising consequently, India faces a challenge in its effort to ensure energy security.
Energy security issue can be encounter by accelerated development of energy infrastructure,
reduced dependency on Import, human development index and technological up-gradation are key
areas for action. Beside that a diverse mix of energy sources, each with different advantages,
provides security to an energy system by allowing flexibility in meeting each country’s needs.
Using clean, renewable energy is one of the most important actions you can take to reduce your
impact on the environment. Renewable energy provides reliable power supplies and fuel
diversification, which enhance energy security, lower risk of fuel spills, and reduce the need for
imported fuels. Renewable energy also helps conserve the nation’s natural resources.
2. ISSUES IN ENERGY SECURITY
India's fragile energy security is under severe pressure from its rising dependence on imported oil,
regulatory uncertainty, small pool of skilled manpower and poorly developed upstream
infrastructure and dependence on fossil fuels as the dominant source of energy in the near future.
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To meet the growing energy demand over the next few years, India will have to enhance its energy
security by procuring energy supplies at affordable prices. While the country has surplus refining
capacity and is an exporter of petroleum products, major investments will have to be made in the
domestic upstream industry and to acquire hydrocarbon reserves abroad.
In India currently, a move towards a diversified fuel basket, together with a focus on efficient
exploration and consumption of energy resources, is needed. Additionally, key areas of action are:
a. Accelerated development of energy infrastructure
b. Human resource development
c.
Technological upgrade
A. Rising dependence on imported oil
Over the past few years country dependence on imported oil has steadily increased as a result of
stagnant domestic production and rising demand. This high dependence on imported crude oil has
significant implication on energy security and the overall financial health of the country domestic
production remained flat, hampered by limited prospectively delays in the commissioning of new
projects and declining production from existing maturing fields. Disruption in crude oil supplies
has always been a cause for concern for India. The Middle East and North Africa, which supplies
60% of India’s oil requirements, have witnessed high degree of geopolitical volatility in recent
times. The recent upheaval in the Middle East, especially in Libya and Egypt triggered a drop in
crude oil production in the region, resulting in increased crude oil prices driving up inflation in
India. According to Goldman Sachs, the increase in oil price by US$10 per barrel could potentially
slow India’s GDP growth by 0.2% and may inflate the current account deficit by 0.4%. in addition,
the increase in oil price could result in foreign exchange reserve. The recent depreciation of the
rupee raised the bill of the crude oil import for India, which in turn has led to increase in
inflammatory pressure in the economy. Further, increase in oil import impact our trade deficit.
India’s requirements of fossil fuels for the year 2030 are projected to be 337 to 462 Mt of oil, 99 to
184 Mtoe of gas and 602 to 954 Mtoe of coal. If the global fossil fuel supply increases by only
1.7%, as projected by IEA, then India’s share in 2030 would range from 5.8% to 8.0% for oil, 2.4%
to 4.5% for natural gas and 16.7% to 26.5% for coal.
B. Inadequate upstream Infrastructure:
The upstream oil and gas infrastructure in India is inadequate due to underinvestment in the past.
As a result, the production of oil and gas remained stagnant and has not been able to keep up with
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the rise in demand. The sector has limited participation from foreign and private players as is
visible from their declining participation in New Exploration Licensing Policy (NELP) rounds. For
instance, a total of 21 foreign companies participated in NELP-VII, ten foreign countries took part
in NELP-VIII, while only eight companies took part in NELP-IX (2011). Further, companies have
spent just US$7.2 billion, out of their investment commitment of US$20.7 billion until NELP VII.
Although the unexplored sedimentary area in the country decreased from 41% in FY99 to 12% in
FY10, the level of exploration will have to be further raised to increase hydrocarbon production.
C. Underdeveloped natural gas infrastructure:
The natural gas infrastructure in the country needs an overhaul. The infrastructure is currently
underdeveloped due to limited availability of natural gas and inadequate transmission and
distribution pipelines. India’s gas pipeline density (pipelines spread per square km) is one of the
lowest in the world. As a result, the share of natural gas in the overall energy mix is only 10% as
against the global average of 24%.
Comparison of pipeline density — 2010
Country
India
UK
US
Pakistan
China
Estimated pipeline density (km/sq. km.)
0.003
0.05
0.05
0.01
0.004
In India, most of the gas production and liquefied natural gas (LNG) terminals were located in the
western part of the country. As a result, the pipeline infrastructure was concentrated only in the
western India, which has adversely impacted the availability of gas in the rest of the country. The
low availability of gas and limited infrastructure has curtailed development of gas market in the
country. Over the next few years, the availability of gas is likely to increase on the back of
incremental supplies of KG-D6 block, as well as from the new gas fields of ONGC, CBM and new
LNG facilities.
C. Acute shortage of skilled human resources:
The oil and gas industry in India is facing a shortage of skilled manpower due to attrition,
retirement and the inability to attract the young force. The industry is unable to attract talent from
universities due to lack of awareness of the available carrier opportunity within the industry and
difficult working conditions, especially in the upstream segment. Other, industry provide attractive
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carrier opportunities. Around 11% of the workforce may retire over the next few years, resulting in
significant loss of experienced personnel. Over the next few years, the shortage of talent is likely to
increase, which may impact operation across the value chain. There will be around 25,000
additional professionals over the next few years due to attrition, retirement and increasing activities
in the industry. the upstream segment is likely to have the highest shortfall of skilled manpower of
around 7,600 employees.
D. Technical risk
Even when the country has adequate energy resources, technical failures may disrupt the supply of
energy to some people. Generators may fail, transmission lines could trip or oil pipelines may
spring leaks. There may be many such accidents that disrupt the supply of energy. One needs to
provide security against such technical risks.
Further, any disruption in access to energy can be very expensive in welfare terms as energy is
critical not only for economic growth but also for human survival and well-being. For example, if
an increase in the price of oil, a disruption of oil supply or erratic power supply forces farmers to
reduce the use of their pumps and tractors, the consequent reduction in agricultural output and
employment can have a serious and adverse impact on the poor. Thus, a government may choose
not to immediately transmit a sudden large increase in the international price of imported energy to
consumers. To be able to insulate consumers against such sudden price increase, governments may
have to bear the burden of this price rise for some time.
On the other side, market risk of a sudden increase in oil price also plays an important role in
energy security. While we may be able to pay for imports, a high oil price can cause inflation, slow
down the economy and impose hardship on our people. Given that world oil prices have fluctuated
substantially over the years, the adverse impact on the economy of sudden and large increases in oil
price is perhaps a more likely risk than supply disruption.
3. IMPROVE ENERGY SECURITY
Actions to improve energy security can be classified broadly into two groups, one that reduces
risks and another that deals with the risks after they occur. The major policy options are:
A. Reducing Risks
1. Reduce the requirement of energy by increasing efficiency in production and use of energy;
2. Reduce import dependence by substituting imported fuels by domestic fuels;
3. Diversify fuel choices and supply sources;
4. Expand domestic energy resource base.
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B. Dealing with Risks
1. Increase ability to withstand supply shocks;
2. Increase ability to import energy and face market risk;
3. Increase redundancy to deal with technical risk
A.1. Reduce Energy Requirement
Energy efficiency and demand side management also have a large scope to reduce energy
requirement. These include the use of energy efficient appliances and automobiles, hybrid cars,
energy efficient buildings, efficient lighting, cogeneration, distributed generation with Combined
Heat and Power (CHP) use, energy efficient and well-maintained irrigation pumps, smokeless
improved woodstoves, etc.
In the long-term, promotion of public transport in urban areas can significantly reduce energy
consumption particularly the need for imported oil and gas. Some advance actions that can be taken
over such as to develop effective and attractive mass transport such as underground, elevated
trains, light rail, monorail or dedicated bus lanes in existing metros. For medium size cities, make
plans for efficient public transport corridors to serve future population and acquire the right of way.
Congestion charges and parking fees should be levied in city centers to discourage the use of
private cars.
A.2. Substitute imported energy by domestic alternative
Energy security can be increased by reducing the need for imported energy by substituting it with
other forms of energy. Though this does not reduce the need for total energy, it reduces import
dependence. If the domestic substitutes increase dependence on one particular fuel, however, it can
increase domestic supply risk. Conversely, if substitutes diversify the domestic energy mix, they
can also reduce supply risk particularly if the substitutes are local renewables. Decentralized
distributed generation (DDG) is one of the innovative approaches adopted by many countries like
Cambodia, Nepal and Philippines and is proving effective in India too. DDG is promoted by GoI
through Rajiv Gandhi Grameen Vidyutikaran Yojana which enables electricity generation at local
level by utilizing local resources and wastes and is usually implemented in remote villages where
connectivity to grid is not possible or not cost effective. It had ensured those villages with
continuous power supply, reduced dependence on external sources and promoted renewables such
as wind, water and biomass.
A.3. Diversify Supply Sources
The forecast growth in energy demand means that we will need many sources of energy now and
into the future. A diverse mix of energy sources, each with different advantages, provides security
to an energy system by allowing flexibility in meeting each country’s needs.
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The impact of a short-term disruption in the normal source of supply will depend on how important
that source is in our total import mix. Thus the first measure for increasing security is to diversify
our sources of supply both domestically as well as for the import of oil or gas. India currently
imports oil from many different countries (from 25 different countries) nearly two-thirds of our
imports are from four countries, i.e. Saudi Arabia, Nigeria, Kuwait and Iran.
Energy security can be increased not only by diversifying sources of import of a particular fuel but
also by diversifying the energy mix by using different types of fuels An economy that uses coal,
oil, gas, nuclear, hydro and renewables of various kinds is naturally less dependent on one
particular fuel, and hence less vulnerable to supply disruptions of either domestic or imported
energy sources. The security provided by such diversification is enhanced when the ability of the
users to switch among fuels increases.
4. GOVERNMENT POLICIES
Bridge the rising demand supply gap, reduce import dependency and make ourselves resilient to
the external factors economic and political disruptions in the sourcing nations, international crude
oil prices the government has initiated several policy and regulatory measures:
New Exploration License Policy (NELP): To increase domestic exploration and production, the
government introduced NELP. During the ninth round of bidding under NELP, there was an
investment commitment of more than USD 827.44 million.
By 2012, the government plans to move towards an Open Acreage Licensing Policy (OALP),
wherein oil and gas acreage will be available round the year instead of cyclical bidding rounds
launched under NELP.
Coal Bed Methane Policy: To stimulate the exploration and production of coal bed methane in the
country, the government introduced the Coal Bed Methane Policy. Till date 33 blocks have been
offered in four rounds of bidding.
Underground Coal Gasification: The pilot production of underground coal gasification would
commence by the end of 2015. ONGC has signed an agreement with Skochinsky Institute of
Mining, Russia to harness world class technology to tap this energy source.
Gas Hydrate is at the research and development stage (during the year 2008, India signed an
agreement with Russia under the Integrated long term programme of cooperation to jointly conduct
research and development for technology required to harness gas hydrates).
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Shale gas policy: By the year 2012, the government plans to announce the Shale gas policy. The
government has been encouraging acquisition of overseas E&P assets. 100% FDI is permitted in
exploration, refining, pipelines and marketing.
5. CLEAN ENERGY
Climate change and energy security are key drivers for future energy policy. While energy security
has been a pillar of energy policy for about a century, concern about climate change is more recent
and is bound to radically change the landscape of energy policy. Policy makers are now under
increasing pressure to address these twin challenges: to develop cost-effective policies that will
both ensure the security of our energy system and reduce greenhouse gas emissions. Therefore, we
need new tools to assess objectively the interactions between the implementation of these multiple
policies and to maximize their impact across these two important goals.
The world is on the cusp of a clean energy revolution. Some new technologies can help provide
clean energy by harnessing the power of the sun, wind, and other renewable resources. Other
technologies can enable more efficient use of energy in buildings, industry, and vehicles. These
technologies, when coupled with supportive policies, can significantly reduce carbon pollution
from traditional fossil fuels, improve local air quality, create jobs, enhance energy security, and
provide improved access to energy around the world. Yet barriers to the adoption of clean energy
technologies abound, and the cost of some technologies remains high. By working together,
governments and other stakeholders can overcome barriers and advance the adoption of clean
energy technologies.
6. IMPORTANCE OF CLEAN ENERGY
Using clean, renewable energy is one of the most important actions you can take to reduce your
impact on the environment. Electricity generation is the leading cause of industrial air pollution.
Most of our electricity comes from coal, nuclear, and other non-renewable power plants. Producing
energy from these resources takes a severe toll on our environment, polluting our air, land, and
water. Renewable energy sources can be used to produce electricity with fewer environmental
impacts. It is possible to make electricity from renewable energy sources without producing carbon
dioxide (CO2), the leading cause of global climate change. But replacing our fossil-fuel
infrastructure will take time and strong, consistent support from both state and federal mandates to
build renewable energy generation and demand for clean energy from consumers and businesses.
Renewables Benefit the Economy- Renewable energy provides reliable power supplies and fuel
diversification, which enhance energy security, lower risk of fuel spills, and reduce the need for
imported fuels. Renewable energy also helps conserve the nation’s natural resources.
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Price Stability- Renewable energy sources such as wind, solar, hydro and geothermal do not entail
fuel costs or requires transportation and therefore offer greater price stability.
REFRENCES
[1]
[2]
[3]
[4]
http://www.eia.gov/countries/regions-topics.cfm?fips=wotc&trk=p3
http://www.worldcoal.org/coal-society/coal-energy-security/
https://www.iea.org/publications/freepublications/publication/energy_security_climate_policy.pdf
http://www.whitehouse.gov/sites/default/files/omb/budget/fy2015/assets/fact_sheets/building-a-cleanenergy-economy-improving-energy-security-and-taking-action-on-climate-change.pdf
[5] http://buycleanenergy.org/why
[6] www.cleanenergyministerial.org/About
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Structural and Photocatalytic Behaviour
of TiO2 and α-Fe2O3-TiO2 Nanorods
Shanmugapriya P1, Pandiyarasan V1, Sanju Rani2, Rajalakshmi N2
Department of Physics and Nanotechnology,
SRM University, Kattankulathur, Kanchipuram, Tamilnadu-603203.
Centre for Fuel Cell and Technology, International Advanced Research Centre for Powder Metallurgy and
New Materials(ARCI), IITM-Research Park, 6, Kanagam Road, Taramani, Chennai, Tamilnadu- 600113.
ABSTRACT
We report the effect of α-Fe2O3 doping (varied weight%) on the photocatalytic activity of TiO2.
Synthesis of TiO2 and α-Fe2O3-TiO2( N1 [0.34wt%], N2 [0.68wt%] ) were done using single step
hydrothermal technique. The structural, morphological and optical characteristics of TiO2 and
doped samples were analyzed by X-Ray Diffractometer (XRD), Scanning Electron Microscope
(SEM), Diffuse Reflectance UV-Vis Spectroscopy (DRS) and Fourier Transform InfraRed
Spetroscopy (FTIR). The photocatalytic property of the samples were studied by the dye
degradation experiment, which was carried out under natural sunlight. The experiments were
carried out for 150 mins and aliquot samples were collected for each of them at the interval of 15
mins. The absorption spectrum of aliquot samples were obtained using UV-Visible
Spectrophotometer to study the rate of degradation. Irradiation time Vs C/C0 graph revealed the
rate of degradation for each sample. The order of reaction, rate constants and half lives were
analysed using ln[C] Vs time graph which exhibited a linear fit for all samples, it shows they
follow first order reaction kinetics. It showed that lower doped nanorods (N1) had greater rate
constant and improved efficiency as compared to others.
Keywords: Photocatalytic activity, TiO2, α-Fe2O3-TiO2, Natural sunlight, nanorods.
1. INTRODUCTION
Waste water has become an alarming problem around the world, which has been resulted through
the discharge of sewage water, industrial wastes, agricultural wastes, ingress of seawater, river
water, manmade liquids, rainfall runoff. This includes discharge of industrial wastes like toxic
wastes, emulsions, industrial process waters, release of dyes from textile industries. The ingress of
excessive dyes into the natural water is often serious concern. The dyes could react with
environmental conditions which will make it more toxic and carcinogenic for aquatic and human
life. The dyes are quiet stable even under sunlight and its difficult to detect their individual
presence for the study of toxicity[1].There are a variety of conventional methods like physical,
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Structural and Photocatalytic Behaviour of TiO2 and ῆ-Fe2O3-TiO2 Nanorods
chemical and biological methods to treat the waste water. These methods were found to be not
paving the way for complete remediation from this issue.
Nanomaterials are highly known for their excellent optical, electronics, chemical properties which
greatly helps in addressing various issues that are not met with bulk materials[2]. One dimensional
nanostructures are of greater interest for a photocatalyst due to its unique optical, structural and
electronic properties. Metal oxide semiconductors are widely used as a photocatalyst due to their
stability, non-toxicity, low cost and tunable properties, possibility of noble metal loading, doping
and sensitization[3]. Among them TiO2, ZnO, WO3, SnO2 are widely studied, where ZnO,WO3 and
SnO2 are performing inferior when compared to TiO2. TiO2 is found to be the most dominating
material as a photocatalyst in dye degradation process owing to its higher photocatalytic
efficiency[4].
The requirements of a good photocatalyst for photodegradation includes maximum utilization of
visible region, higher efficiency, mineralization of the dye molecules, separation and reusability of
the photocatalyst. TiO2 was being widely studied, which is considered to be the dominating
material in photodegradation. But it has a disadvantage of wide bandgap (3.2eV) due to which it is
not able to absorb visible light. Here, we have reported TiO2 and α-Fe2O3-TiO2 nanorods, of which
α-Fe2O3-TiO2 has shown enhanced photocatalytic activity under sunlight.
2. EXPERIMENTAL METHODS
All the chemical reagents were analytically pure and were used without any further purification.
The synthesis of TiO2 and α-Fe2O3-TiO2 samples was carried out using a single step hydrothermal
technique. 10 M aqueous solution of Sodium Hydroxide (NaOH) was prepared by stirring for
15mins at room temperature. 2gms of TiO2 powder was added to the NaOH solution under
stirring. α-Fe2O3-TiO2 was also prepared using the aforementioned procedure with the addition of
0.34wt% (N1) and 0.68wt% (N2) of FeCl3 to the precursor. The precursor was transferred to the
100ml Teflon lined autoclave. It was sealed, kept in furnace and the temperature is maintained at
1600. After 24hours, the autoclave was removed and allowed to cool down at room temperature.
The resulted solid mass in the autoclave was washed with distilled water several times and
separated by centrifugation, dried in hot air oven at 600 for about 8hrs. The dried powder was
crushed and stored for further characterizations and studies.
3. SAMPLE CHARACTERIZATIONS
The crystallinity and phase analysis of the samples were done using PANalytical X Ray
Diffractometer using Cu Kα radiation (t=1.54056Å) with 2θ ranging from 200 to 800. Fourier
Transform InfraRed Spectroscopy (Alpha-T FT-IR Spectrometer) was used to study the functional
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Shanmugapriya P, Pandiyarasan V, Sanju Rani, Rajalakshmi N
groups formed in the samples. The diffuse reflectance spectrum were obtained using Diffuse
Reflectance UV-Vis Spectroscopy (JASCO V-650) in the wavelength range of 200 to 800nm in
order to calculate the bandgaps of the material. The surface morphology of the samples were seen
using Scanning Electron Microscope (FEI QuantaTM 100). The photocatalytic activity of all the
samples were studied by dye degradation experiment using Methylene Blue(MB) dye. The initial
concentration was 6.25µM (200µl in 100ml distilled water) and 1gm of the sample was loaded to
the MB solution. The photocatalytic study was done under natural sunlight for about 150mins and
the aliquot samples were collected at the time interval of 15mins. The absorption spectrum of
aliquot samples were obtained by UV-Visible Spectrophotometer (UV 3000+) in the wavelength
range of 200-800nm.
4. RESULTS AND DISCUSSIONS
4.1 XRD
The XRD pattern of TiO2 and α-Fe2O3-TiO2 (N1 and N2) were shown in Fig1. All the peaks in
each diffraction pattern correspond to anatase phase of TiO2[5,6,7] however in case of doped
samples there were traces of α-Fe2O3[(104),(110)]. It was observed that the peak intensity of the
planes (104),(110) corresponding to α-Fe2O3 was increased with increase in doping concentration.
It was also observed that the peak corresponding to anatase TiO2 was deacreasing and FWHM was
broadening with increase in α-Fe2O3 doping. It shows that there was reduction in crystallite size
and
increase
in
surface
area
with
α-Fe2O3
doping
as
compared
to
215
204
116
220
200
105
211
103
004
112
101
N2
N1
TiO2
Transmittance (%)
Counts
* - α Fe2O3
*104
*110
N2
N1
TiO2
**
1644 1462
3480
487
1644
3448
1450
487
1644
1642
3448
20
40
Position ( 2θ )
60
80
4000
3500
513
3000
2500
2000
1500
1000
500
-1
Wavenumber (cm )
Fig 1showing XRD pattern of TiO2, N1 and N2
Fig 2 showing FTIR spectrum of TiO2, N1
and N2
4.2 FTIR
Fig2. Shows the FTIR spectrum of all the samples in the range of 400-4000cm-1. The patterns were
found to have peaks around the region of 3400cm-1, 1640cm-1, 1450cm-1 and 480/500cm-1. There
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Structural and Photocatalytic Behaviour of TiO2 and ῆ-Fe2O3-TiO2 Nanorods
was reduction in the intensity of all the peaks with the incorporation of α- Fe2O3. The broad peaks
found in the region of 3450 cm-1 and 1650 cm-1 corresponds to the stretching and bending
vibrations of –OH group[8]. These groups play a major role in the phase formation as well as in
phase stabilization of all the samples[9]. In the photocatalytic dye degradation experiments –OH
group plays a vital role. During the reaction, it prompts to react with photogenerated holes in order
to degrade the dye into intermediate products leading to mineralisation[10]. The peak observed in
the region of 513cm-1 for TiO2 correspond to Ti-O bond, were observed to be shifted to 487cm-1
with doping, which associates with Fe-O stretching mode.
4.3 DRS
The absorption spectrum of TiO2 and α-Fe2O3 doped samples were depicted in Fig3a. The spectra
of TiO2 revealed an absorption edge at 380nm. The spectrum of α-Fe2O3 doped samples exhibited
broad absorption in the visible region (450-600nm) as compared to TiO2. This shows there is a
bathochromic (red) shift in the absorption region which leads to reduction in the bandgap of the
material[11,12].
1.0
TiO2
N1
N2
Absorbance (a.u.)
0.8
0.6
0.4
0.2
0.0
200
300
400
500
600
700
800
Wavelength (nm)
Fig3 showing DRS UV-Vis spectrum
Fig4 showing SEM image of N1
4.4 SEM
The SEM images are shown in Fig4. The images clearly depict the formation of uniformly
distributed nanorods. The morphology of the samples were not affected due to doping. There was
formation of one dimensional nanostructures, an important concern for the photocatalytic activity.
4.5 Degradation Studies
Fig6(a, b, c) shows the UV visible absorption spectrum of gradual degradation in Methylene
Blue(MB) dye in the presence of the photocatalysts(TiO2, N1, N2 respectively). All the graphs
show a gradual degradation had taken place. In case of α-Fe2O3 doped samples, there was the
hypsochromic (blue) shift in the spectrum (Fig 6b, 6c). This might be due to the demethylation of
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Shanmugapriya P, Pandiyarasan V, Sanju Rani, Rajalakshmi N
the MB and formation of other intermediate products under sunlight[13]. The degradation rate for
all the samples were analysed using irradiation time Vs C/C0 curve (Fig 6d). It shows that rate of
degradation is increased with that of doped samples (N1,N2) than in TiO2. Rate constants and Half
Lives had been calculated which is listed in Table1. All the samples were following first order
reaction kinetics and the rate constant was highest for N1 among them. The table shows that higher
the rate constant, lesser the half life. The degradation efficiency[14] have been calculated using the
formula (1-(Ct/C0))*100 which showed greater efficiency with lower doped sample(N1). The
efficiencies were found to be 92%, 95.07% and 94.08% for TiO2, N1, and N2 respectivley.
MB
MB 2 and 1/2
TiO2 15m
TiO2 30m
TiO2 45m
TiO2 60m
TiO2 75m
TiO2 90m
TiO2 105m
TiO2 120m
TiO2 150m
2.5
Absorbance (a.u,)
2.0
1.5
1.0
0.5
3.0
MB
MB 21/2 h
N1 15m
N1 30m
N1 45m
N1 60m
N1 75m
N1 90m
N1 105m
N1 120m
N1 150m
2.5
2.0
Absorbance (a.u,)
3.0
1.5
1.0
0.5
0.0
0.0
400
500
600
700
800
400
500
Wavelength (nm)
600
700
800
Wavelength (nm)
Fig 6a
Fig6b
3.0
Absorbance (a.u,)
2.0
1.5
1.0
N2
N1
TiO2
1.0
0.8
0.6
C/C0
MB
MB 21/2 h
N2 15m
N2 30m
N2 45m
N2 60m
N2 75m
N2 90m
N2 105m
N2 120m
N2 150m
2.5
0.4
0.2
0.5
0.0
0.0
400
500
600
700
800
0
20
Wavelength (nm)
40
60
80
100
120
140
160
Time (min)
Fig 6c
Fig6d
Table1 showing the rate constants, Half lives and Efficiencies of all samples
Sample name
TiO2
N1
N2
Order of the
reaction
First
First
First
Rate constant (10-2min-1)
Half Life (t1/2)
4.46
7.45
4.19
15.54
9.35
16.54
Efficiency
(%)
92
95.08
94.07
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Structural and Photocatalytic Behaviour of TiO2 and ῆ-Fe2O3-TiO2 Nanorods
5. CONCLUSION
TiO2 and α-Fe2O3-TiO2 (N1,N2) nanorods had been prepared using a simple one step hydrothermal
technique. It was observed that there was reduction in the bandgap on α-Fe2O3 doping. The
degradation studies have revealed that doping with lower concentration of α-Fe2O3 could enhance
the photocatalytic activity to an extent which further reduces the enhancement on increase in
doping concentration.
REFERENCES
[1] Ratna, Padhi. B.S, Pollution due to synthetic dyes toxicity & carcinogenicity studies and Remediation,
International Journal of Environmental Sciences Volume 3, No 3, 2012, ISSN 0976 – 4402, 940-955.
[2] Emil Roduner, Size matters: why nanomaterials are different, Royal Society of Chemistry, Chem. Soc.
Rev., 2006, 35, 583–592.
[3] Zaharia Carmen and Suteu Daniela, Textile Organic Dyes – Characteristics, Polluting Effects and
Separation/Elimination Procedures from Industrial Effluents – A Critical Overview, Organic Pollutants
Ten Years After the Stockholm Convention – Environmental and Analytical Update, ISBN 978-953307-917-2, 55-86.
[4] Samuel Hong Shen Chan, Ta Yeong Wu, Joon Ching Juan and Chee Yang The, Recent developments of
metal oxide semiconductors as photocatalysts in advanced oxidation processes (AOPs) for treatment of
dye waste-water, DOI 10.1002/jctb.2636, J Chem Technol Biotechnol2011, Society of Chemical
Industry, 86: 1130–1158.
[5] GUPTA Shipra Mital and TRIPATHI Manoj, A review of TiO2nanoparticles, Chinese Science Bulletin,
Physical Chemistry - Review, doi: 10.1007/s11434-011-4476-1, June 2011 Vol.56 No.16: 1639–1657.
[6] Hakan Ceylan,Cagla Ozgit-Akgun,Turan S. Erkal,Inci Donmez,Ruslan Garifullin,Ayse B.
Tekinay,Hakan Usta,Necmi Biyikli & Mustafa O. Guler, Size-controlled conformal nanofabrication of
biotemplated three-dimensional TiO2and ZnO nanonetworks, SCIENTIFIC REPORTS| 3 : 2306 | DOI:
10.1038/srep02306.
[7] Chin-Jung Lin, Wen-Yueh Yu, Yen-Tien Lu and Shu-Hua Chien, Fabrication of opened-end highaspect-ratio anodic TiO2 nanotube film for photocatalytic and photoelectrocatalytic applications,
Electronic Supplementary Material (ESI) for Chemical Communications, The Royal Society of
Chemistry 2008.
[8] M.A. Ahmeda, Emad E. El-Katori, Zarha H. Gharni, Photocatalytic degradation of methylene blue dye
using Fe2O3/TiO2 nanoparticles prepared by sol–gel method, Journal of Alloys and Compounds 553
(2013) 19–29.
[9] Xian-Ming Liu, Shao-Yun Fu, Hong-Mei Xiao, Chuan-Jun Huang, Preparation and characterization of
shuttle-like a-Fe2O3 nanoparticles by supermolecular template, Journal of Solid State Chemistry 178
(2005) 2798–2803.
[10] S. K. Apte, S. D. Naik, R. S. Sonawane, and B. B. Kale, Synthesis of Nanosize-Necked Structurea-andcFe2O3and its Photocatalytic Activity, J. Am. Ceram. Soc.,90[2] (2007) 412–414.
[11] Biswajit Choudhury, Munmun Dey and Amarjyoti Choudhury, Defect generation, d-d transition, and
band gap reduction in Cu-doped TiO2 nanoparticles, International Nano Letters 2013 3:25 1-8.
[12] Mohammad Mansoob Khan, Sajid A. Ansari, D. Pradhan, M. Omaish Ansari, Do Hung Han, Jintae Lee
and Moo Hwan Cho, Band gap engineered TiO2 nanoparticles for visible light induced
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photoelectrochemical and photocatalytic studies, Royal Society of Chemistry, J. Mater. Chem. A, 2014,
2, 637–644.
[13] Damian Marcinkowski,Monika Wałe˛sa-Chorab,Violetta Patroniak,Maciej Kubicki, Grzegorz
Ka˛dziołka and Beata Michalkiewicz, A new polymeric complex of silver(I) with a hybridpyrazine–
bipyridine ligand – synthesis, crystal structure and its photocatalytic activity, Royal Society of
Chemistry, New J. Chem.,38 (2014) 604-610.
[14] N.P.Mohabansi, V. B. Patil and N.Yenkie, A Comparative Study on Photodegradation of Methylene
Blue dye effluent by Advanced Oxidation Process by using TiO2/ZnO Photocatalyst, Rasayan Journal of
Chemistry, Vol.4, No.4 (2011) 814-819, ISSN: 0974-1496.
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A Process Model to Estimate Biodiesel and Petro Diesel
Requirement and Mass Allocation Rule
Aprajita Chauhan, Shuchi Verma, Vinay K.Singh
Dept of Chemistry, Sri Aurobindo College, Delhi University
ABSTRACT
The life cycle assessment (LCA) for the production of biodiesel in USA was done by National
Renewable Energy Laboratory (NREL) in 1998.W have focused on the benefits related to
biodiesel energy’s balance, its effect on the effect of biodiesel on overall consumption and mass
allocation with petro diesel and other fossil fuels. In the context of this, fuel’s “life cycle”—the
sequence of steps involved in making and using the fuel from the extraction of all raw materials
from the environment to the final end-use of the fuel in an urban bus., as well as for blends of
biodiesel with petroleum diesel. The scope of this study Life cycle analysis is a complex science.
The level of detail required in such a study forces a high degree of specificity in the scope and
application of the products being studied. Here we study life cycle analysis , a computational tool
for assessing the requirement and production of biofuels and petro-diesel.
1. INTRODUCTION
Life Cycle analysis (LCA) provide an opportunity to quantify the total energy demands and the
overall energy efficiencies of processes and products. Ascertaining the overall energy requirements
of biodiesel is key to our understanding of the extent to which biodiesel made from oil is a
“renewable energy” source. More the fossil energy required to make a fuel, the less that this fuel is
deemed “renewable”. Thus, the renewable nature of a fuel can vary across the spectrum of
“completely renewable.” (i.e., no fossil energy input) to nonrenewable (i.e., fossil energy inputs as
much or more than the energy output of the fuel)[2] . Energy efficiency estimates help us to
determine how much additional energy must be expended to convert the energy available in raw
materials used in the fuel’s life cycle to a useful transportation fuel. The basic concepts as well as
the results of our analysis of the life cycle energy balances for biodiesel and petroleum diesel are as
follows:[1]
1.1 Types of Life Cycle Energy Inputs
In this study, several types of energy flows through each fuel life cycle.
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Aprajita Chauhan, Shuchi Verma, Vinay K.Singh
•
•
•
•
•
Total Primary Energy. All raw materials extracted from the environment can contain energy.
In estimating the total primary energy inputs to each fuel’s life cycle, the cumulative energy
content of all resources extracted from the environment.
Feedstock Energy. Energy contained in raw materials that end up directly in the final fuel
product is termed “feedstock energy.” For biodiesel production, feedstock energy includes the
energy contained in the soybean oil and methanol feedstocks that are converted to biodiesel.
Likewise, the petroleum directly converted to diesel in a refinery contains primary energy that
is considered a feedstock energy input for petroleum diesel. Feedstock energy is a subset of the
primary energy inputs.
Process Energy. The second major subset of primary energy is “process energy.” This is
limited to energy inputs in the life cycle exclusive of the energy contained in the feedstock. It is
the energy contained in raw materials extracted from the environment that does not contribute
to the energy of the fuel product itself, but is needed in the processing of feedstock energy into
its final fuel product form. Process energy consists primarily of coal, natural gas, uranium, and
hydroelectric power sources consumed directly or indirectly in the fuel’s life cycle.
Fossil Energy. Since the renewable nature of biodiesel is of primary concern, we also track the
primary energy that comes from fossil sources specifically (coal, oil, and natural gas). All three
of the previously defined energy flows can be categorized as fossil or non fossil energy.
Fuel Product Energy. The energy contained in the final fuel product, which is available to do
work in an engine, is the “fuel product energy”. All other things being equal, fuel product
energy is a function of the energy density of each fuel. We consider the energy trapped in
soybean oil to be renewable because it is solar energy stored in liquid form through biological
processes that are much more rapid than the geologic time frame associated with fossil energy
formation. Also, other forms of nonrenewable energy besides fossil fuel exist.The energy
“contained” in a raw material is the amount of energy that would be released by the complete
combustion of that raw material.[3-7]
Life Cycle Inventory of Biodiesel and Petroleum Diesel 11 NREL/SR-580-2408
In this paper two types of energy efficiency are considered. The first is the overall “life cycle
energy efficiency”. The second is what we refer to as the “fossil energy ratio”. Each elucidates a
different aspect of the life cycle energy balance for the fuels studied.The calculation of the life
cycle energy efficiency is simply the ratio of fuel product energy to total primary energy:
Life Cycle Energy Efficiency = Fuel Product Energy/Total Primary Energy
Fossil Energy Ratio = Fuel Energy/Fossil Energy Inputs
If the fossil energy ratio has a value of zero, a fuel is not only completely nonrenewable, but it
provides no useable fuel product energy as a result of the fossil energy consumed to make the fuel.
If the fossil energy ratio is equal to 1, then this fuel is still nonrenewable. A fossil energy ratio of
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A Process Model to Estimate Biodiesel and Petro Diesel Requirement and Mass Allocation Rule
one means that no loss of energy occurs in the process of converting the fossil energy to a useable
fuel. For fossil energy ratios greater than 1, the fuel actually begins to provide a leveraging of the
fossil energy required to make the fuel available for transportation. As a fuel approaches being
“completely” renewable, its fossil energy ratio approaches “infinity.” In other words, a completely
renewable fuel has no requirements for fossil energy.
From a policy perspective, It is important to understand the extent to which a fuel increases the
renewability of our energy supply. Another implication of the fossil energy ratio is the question of
climate change. Higher fossil energy ratios imply lower net CO2 emissions. This is a secondary
aspect of the ratio, as we are explicitly estimating total CO2 emissions from each fuel’s life cycle.
Nevertheless, the fossil energy ratio serves as a check on calculation of CO2 life cycle flows.[9]
As Life cycle analysis is a complex science. The level of details required in such a study forces a
high degree of specificity in the scope and application of the products being studied.We have also
undertaken studies in our laboratory to characterize the performance of linseed derived biodiesel
for life cycle analysis. More importantly, our sensitivity studies show that the estimates of energy
requirements are very healthy that is, these results show little change in response to changes in key
assumptions.
The use of biodiesel offers tremendous potential for the strategy for reducing petroleum oil
dependence and minimizing fossil fuel consumption. Substituting 100% biodiesel (B100) for
petroleum diesel in buses reduces the life cycle consumption of petroleum by 95%. This benefit is
proportionate with the blend level of biodiesel used. When a 20% blend of biodiesel and petroleum
diesel (B20) is used as a substitute for petroleum diesel in urban buses, the life cycle consumption
of petroleum drops by 19%.In our study, biodiesel and petroleum diesel are producing almost
identical efficiency of converting a raw energy source (in this case, petroleum and linseed oil) into
a fuel product. The difference between these two fuels is in the ability of biodiesel to utilize a
renewable energy source.
Biodiesel yields 3.2 units of fuel product energy for every unit of fossil energy consumed in its life
cycle. The production of B20 yields 0.98 units of fuel product energy for every unit of fossil energy
consumed. In contrast, petroleum diesel’s life cycle yields only 0.83 units of fuel product energy
per unit of fossil energy consumed. Such measures confirm the “renewable” nature of biodiesel At
the outset, we designed this study to identify and quantify the advantages of biodiesel as a
substitute for petroleum diesel. These advantages are substantial; especially in the area of
requirement and mass allocation conversion rule .We see these as opportunities for further research
to resolve these concerns.
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Aprajita Chauhan, Shuchi Verma, Vinay K.Singh
2. PETROLEUM DIESEL LIFE CYCLE ENERGY CONSUMPTION
The total primary energy requirements for the key steps in the production and use of petroleum
diesel shown in table 1. The LCI model shows that 1.2007 MJ of primary energy is used to make 1
MJ of petroleum diesel fuel. This corresponds to a life cycle energy efficiency of 83.28%. The
distribution of the primary energy requirements for each stage of the petroleum diesel life cycle is
shown in Table 3. Ninety-three percent of the primary energy demand is for extracting crude oil
from the ground. The stages of petroleum diesel production are ranked from highest to lowest in
terms of primary energy demand About 88% of the energy shown for crude oil extraction is
associated with the energy value of the crude oil itself. The remaining 7% of the primary energy
use the crude oil refinery step for making diesel fuel dominates. Removing the feedstock energy of
the crude itself from the primary energy total allows us to analyze the relative contributions of the
process energy used in each life cycle. Process energy demand represents 20% of the energy is
determined. Using the total primary energy reported in Table 1, Fuel Product ultimately available
in the petroleum diesel.
Life Cycle Energy Efficiency = 1 MJ of fuel product. About 90% of the total process energy is in
refining (60%) and extraction (29%). The next largest contribution to total process energy is for
transporting foreign crude oil to domestic petroleum refiners.[7]
Table 1: Primary Energy Requirements for the Petroleum Diesel Life Cycle
Stage
Domestic Crude Production
Foreign Crude Oil Production
Domestic Crude Transport
Foreign Crude Transport
Crude Oil Refining
Diesel Fuel Transport
Total
Primary Energy (MJ per MJ of Fuel)
0.5731
0.5400
0.0033
0.0131
0.0650
0.0063
1.2007
Percent
47.73%
44.97%
0.28%
1.09%
5.41%
0.52%
100.00%
Foreign crude oil transportation carries with it a fourfold penalty for energy consumption compared
to domestic petroleum transport since the overseas transport of foreign oil by tanker increases the
factor of four due to transport.
Domestic crude oil extraction is more energy intensive than foreign crude oil production. The
United States represent 11% of the total production volume, compared to 3% for foreign oil
extraction for the advance oil recovery. Advanced oil recovery uses twice as much primary energy
per kilogram of oil compared to conventional extraction. Advanced crude oil extraction requires
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A Process Model to Estimate Biodiesel and Petro Diesel Requirement and Mass Allocation Rule
almost 20 times more process energy for per kilogram of oil out of the ground, than onshore
domestic crude oil extraction because the processes employed are energy intensive and the amount
of oil recovered is low associated with the linseed oil itself. As with the petroleum life cycle, the
stages of the life cycle that are burdened with the feedstock energy overpower all other stages. Had
the linseed oil energy been included with the farming operation, then linseed agriculture would
have been the dominant consumer of primary energy. This is analogous to placing the crude oil
feedstock energy in the extraction stage for petroleum diesel fuel. The next two largest primary
energy demands are for linseed crushing and linseed oil conversion. They account for most of the
remaining 13% of the total demand.
Table 2: Fossil Energy Requirements for the Petroleum Diesel Life Cycle
Stage
Domestic Crude Production
Foreign Crude Oil Production
Domestic Crude Transport
Foreign Crude Transport
Crude Oil Refining
Diesel Fuel Transport
Total
Fossil Energy (MJ per MJ of Fuel)
0.572809
0.539784
0.003235
0.013021
0.064499
0.006174
1.199522
Percent
47.75%
45.00%
0.27%
1.09%
5.38%
0.51%
100.00%
Bio-diesel Life Cycle Energy Consumption
If process energy separates from primary energy, we find that energy demands in the biodiesel life
cycle are not dominated by linseed oil conversion (Figure 3). The soybean crushing and soy oil
conversion to biodiesel demand the most process energy (34.25 and 34.55%, respectively, of the
total demand). Agriculture accounts for most of the remaining process energy consumed in life
cycle for biodiesel (almost 25% of total demand). Each transportation step is only 2%-3% of the
process energy used in the life cycle.
Table 3: Primary Energy Requirements for Biodiesel Life Cycle
Stage
Linseed Agriculture
Linseed Transport
Linseed Crushing
Linseed Transport
Linseed Conversion
Biodiesel Transport
Total
Primary Energy (MJ per MJ of Fuel)
0.0660
0.0034
0.0803
0.0072
1.0801
0.0044
1.2414
Percent
5.32%
0.27%
6.47%
0.58%
87.01%
0.35%
100.00%
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Aprajita Chauhan, Shuchi Verma, Vinay K.Singh
Table 3 summarize the fossil energy requirements for the biodiesel life cycle. Since 90% of its
feedstock requirements are renewable (that is, soybean oil), biodiesel’s fossil energy ratio is
favorable. Biodiesel uses 0.3110 MJ of fossil energy to produce one MJ of fuel product; this
equates to a fossil energy ratio of 3.215. In other words, the biodiesel life cycle produces more than
three times as much energy in its final fuel product as it uses in fossil energy. Fossil energy demand
for the conversion step is almost twice that of its process energy demand, making this stage of the
life cycle the largest contributor to fossil energy demand. The use of methanol as a feedstock in the
production of biodiesel accounts for this high fossil energy demand. We have counted the
feedstock energy of methanol coming into the life cycle at this point, assuming that the methanol is
produced from natural gas. This points out an opportunity for further improvement of the fossil
energy ratio by substituting natural gas-derived methanol with renewable sources of methanol,
ethanol or other alcohols.
3. EFFECT OF BIODIESEL ON LIFE CYCLE ENERGY DEMANDS
Life cycle energy efficiency of biodiesel is 80.55%, compared to 83.28% for petroleum diesel. The
slightly lower efficiency reflects a slightly higher demand for process energy across the life of
cycle for biodiesel. On the basis of fossil energy inputs, biodiesel enhances the effective use of this
finite energy resource. Biodiesel leverages fossil energy inputs by more than three to one.
4. STUDY OF MASS ALLOCATION RULE
For biodiesel
Several processes within the biodiesel and the petroleum diesel life cycles produce more than one
product. This life cycle study is concerned only with the portion of the environmental flows that is
attributable to the biodiesel or petroleum-based diesel LCIs. Therefore, the original LCI flows of a
process (emissions, energy and material requirements, etc.) that produce more than one coproduct
are split between the various products produced. A mass based allocation is used for the baseline
comparison of biodiesel and petroleum-based diesel fuel. The following example shows how a
mass allocation works in the case of allocating the soybean conversion into biodiesel
environmental flows between multiple coproducts:
First, the overall environmental flows are determined for a specific process, as shown in Table 13
for soybean conversion into biodiesel.
Table 4: Environmental Inflows and Outflows for the Biodiesel Conversion Process
Environmental Flow
IN:
Linseed Oil (degummed)
Sodium Hydroxide (NaOH, 100%)
Units
kg
kg
Value
1.04
0.0023
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A Process Model to Estimate Biodiesel and Petro Diesel Requirement and Mass Allocation Rule
Methanol (CH3OH)
Electricity
Steam
Water Used (total)
Sodium Methoxide (CH3ONa)
OUT: Biodiesel (neat, kg)
Crude Glycerine
Soapstock
Water (chemically polluted)
Waste (total)
kg
MJ elec
kg
L
kg
kg
kg
kg
L
kg
0.096
0.23
1.03
0.36
0.024
1.04
0.9
0.00054
0.38
0.012
The mass percent of each coproduct produced is calculated, as shown in Table 14:
Table 5: Mass Percent of the Various Conversion Co-Products
Coproducts
Biodiesel (neat, kg)
Crude Glycerine
Soapstock
Total:
Units
kg
kg
kg
kg
Value
1
0.15
0.00054
1.15
Mass Percent of Total
92%
8%
0% (negligible)
100%
The choice of allocation rules can be quite controversial. The assumption of a mass allocation rule
applied to multi-product processes was a subject of real debate among the stakeholders. The mass
allocation approach was seen as the least problematic approach to use.
Finally, the overall environmental flows are allocated to only the production of biodiesel, as shown
in Table 6.
Table 6: Mass Allocated Conversion Results for Biodiesel
Total Process
Environmental Flow
IN:
Linseed Oil (degummed)
Sodium Hydroxide (NaOH, 100%)
Methanol (CH3OH)
Electricity
Steam
Water Used (total)
Sodium Methoxide (CH3ONa) kg
Biodiesel Only
Units
Values Allocation Results
kg
1.04 x 0.92 = 0.96
kg
0.0023 x 0.92 = 0.0021
kg
0.096 x 0.92= 0.088
MJ
0.23 x 0.92= 0.21
kg
1.03 x 0.92 = 0.94
kg
0.36 x 0.92 = 0.33
0.024 x 0.92 = 0.022
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OUT: Biodiesel (neat, kg)
Crude Glycerine
Soapstock
Water (chemically polluted)
Waste (total)
kg
kg
kg
kg
kg
1.04x1.04= 1.081
0.9 x 0 = 0
0.00054 x 0 = 0
0.38 x 0.92 = 0.34
0.012 x 0.92 = 0.011
Similarly, a mass based allocation can be performed for the production of crude glycerine, Table 7.
We don’t actually carry out the calculations for allocation of life cycle flows to glycerine in our
model because our analysis is concerned with those flows allocated only to biodiesel. We show this
calculation to demonstrate that the mass balance for all flows is not violated by the application of
allocation factors, as long as all coproducts are treated the same way when flows are allocated to
them. In this example, in other words, combining the final columns of Table 7 and Table 6 will
yield the overall results for biodiesel conversion as shown in Table 8.
The allocated and unallocated mass and energy balances for the two systems considered in this
study. These table demonstrate the complexity of the systems we are modeling. A comparison of
the allocated and unallocated primary energy inputs for both of these fuels shows that, without
allocation, the energy consumption assigned to make each fuel is much higher than the value of the
fuel. This is due to the fact that the energy inputs that occur in each life cycle contribute to
production of many other products besides petroleum diesel and biodiesel. The application of
allocation rules provides an approximate means for assigning energy inputs in the life cycle among
all of the products involved.
Table 7: Mass Allocated Conversion Results for Glycerine (not used in this study)
Total Process
Glycerine Only Glycerine Only
Environmental Flow
Units Values
Allocation
Results
IN:
Linsed Oil (degummed)
kg
1.04
x 0.08 =
0.083
Sodium Hydroxide (NaOH, 100%)
kg
0.0023
x 0.08 =
0.000018
Methanol (CH3OH)
kg
0.096
x 0.08 =
0.0076
Electricity
MJ
0.23
x 0.08 =
0.00184
Steam
kg
1.03
x 0.08 =
0.0824
Water Used (total)
kg
0.36
x 0.08 =
0.0288
Sodium Methoxide (CH3ONa) kg
0.024
x 0.08 =
0.00192
OUT: Biodiesel (neat, kg)
kg
1.04
x0=
0
Crude Glycerine
kg
0.9
x1=
0.09
Soapstock
kg
0.00054
x0=
0
Water (chemically polluted)
kg
0.38
x 0.08 =
0.0304
Waste (total)
kg
0.012
x 0.08 =
0.00096
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A Process Model to Estimate Biodiesel and Petro Diesel Requirement and Mass Allocation Rule
Table 8: Biodiesel Conversion Process Flows per Coproduct
Biodiesel Only
Glycerine Only
Total Process
Environmental Flow
units
Results
Results
Values
IN:
Linsee Oil (degummed) kg
0.96 +
0.083 =
1.79
Sodium Hydroxide (NaOH, 100%)
kg 0.0021
+
0.000018 =
0.0021
Methanol (CH3OH)
kg 0.088
+
0.0076 =
0.096
Electricity
MJ
0.21 +
0.0019=
0.21
Steam
kg
0.94 +
0.082=
1.022
Water Used (total)
kg
0.33
+
0.029 =
0.36
Sodium Methoxide (CH3ONa) kg
0.022 +
0.0019 =
0.024
OUT: Biodiesel (neat, kg)
kg
1.081 +
0=
1.081
Crude Glycerine
kg
0
+
0.09=
0.09
Water (chemically polluted)
kg
0.34 +
0.0304 =
0.37
Waste (total)
kg
0.011 +
0.00096=
0.012
For Petro-diesel
Three separate types of processes for extracting crude oil are modeled in the petroleum extraction
system , based on a recent life cycle study of U.S. petroleum production processes (Tyson et al.
1993). The three processes are onshore production, offshore production, and enhanced recovery.
Enhanced recovery entails the underground injection of steam (produced by natural gas boilers)
and CO2 to force the crude oil to the surface. The shares of total crude oil recovered by each
process, for domestic and foreign production, are shown in Table 9.
Within the enhanced/advanced crude oil extraction category, two processes are typically used with
different energy and material requirements: steam injection and CO2 injection. Steam injection is
assumed to account for 63% of the enhanced/advanced extraction, and CO2 injection is assumed to
account for the remaining 37%.[8]
Table 9: Production of Crude Oil by Technology Type and Origin
Technology Type
Conventional Onshore
Conventional Offshore
Enhanced/Advanced
Domestic Crude Oil
Production
69%
20%
11%
Foreign Crude Oil
Production
77%
20%
3%
Diesel Fuel Production
Petroleum refineries produce a number of products from the crude oil they receive. This study is
Deal with one specific product, i.e.2 low-sulfur diesel fuel. Therefore, a method of allocating total
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Aprajita Chauhan, Shuchi Verma, Vinay K.Singh
refinery energy use and total refinery emissions between #2 low-sulfur diesel fuel and the other
products needs to be developed.
The simplest allocation procedure (and the baseline case for this study) is to allocate total refinery
inputs and releases among the products on a mass output basis. Table 10 outlines how thisconcept,
based on the output of all U.S. refineries.
Table 46: Total U.S. Refinery Production
Refinery Flow
Diesel Oil (< 0.05% Sulfur, kg)
Diesel Oil (> 0.05% Sulfur, kg)
Gasoline
Heavy Fuel Oil
Jet Fuel (kg)
Kerosene (kg)
Misc. Refinery Products (kg)
Petroleum Coke (kg)
Liquefied Petroleum Gas
Asphalt (kg)
Lubricants (kg)
Petrochemical Feedstocks (kg)
Petroleum Waxes (kg)
Naphthas (kg)
Total:
Mass (kg/yr)
9.12E+10
6.91E+10
3.00E+11
4.21E+10
6.79E+10
2.72E+09
2.50E+09
4.12E+10
4.65E+09
2.62E+10
8.87E+09
2.18E+10
1.21E+09
2.76E+09
6.83E+11
Mass (%)
13.4%
10.1%
44.0%
6.17%
9.95%
0.40%
0.37%
6.04%
0.68%
3.83%
1.30%
3.19%
0.18%
0.41%
100%
Based on this table for crude oil refining, 13.4% of the total emissions, raw materials, and energy
use required by the refinery are allocated to the production of low-sulfur diesel fuel. This approach
ignores issues such as determining the contribution of inputs and releases that are uniquely
associated with diesel versus the other refinery products, but it is consistent with the use of U.S.
average data on refineries used in this analysis.
5. CONCLUSION
Energy Balance. Biodiesel and petroleum diesel have very similar energy efficiencies. The base
case model estimates life cycle energy efficiencies of 80.55% for biodiesel versus 83.28% for
petroleum diesel. The lower efficiency for biodiesel reflects slightly higher process energy
requirements for converting the energy contained in linseed oil to fuel. In terms of effective use of
fossil energy resources, biodiesel yields around 3.2 units of fuel product energy for every unit of
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A Process Model to Estimate Biodiesel and Petro Diesel Requirement and Mass Allocation Rule
fossil energy consumed in the life cycle. By contrast, petroleum diesel’s life cycle yields only 0.83
units of fuel product energy per unit of fossil energy consumed. Such measures confirm the
“renewable” nature of biodiesel. The life cycle for B20 has a proportionately lower fossil energy
ratio (0.98 units of fuel product energy for every unit of fossil energy consumed) and hence ratio
reflects the impact of adding petroleum diesel into the blend.
The Model Used to estimate the energy required to convert linseed oil into biodiesel represent a
linseed processing plant combined with a transesterification unit.the resultfrom this research
suggested a likely improvement of biodiesel FER over time. All other factors are constant for every
100 kg increase in linseed oil yield.
REFRENCES
[1] 1.Life Cycle Inventory of Biodiesel and Petroleum Diesel 47 NREL/SR-580-24089
[2] 2.Fernandes, S.D.et al (2007) Global biofuels use, 1850-2000. Global Biogeochem. Cycles,21 GB 2019
DOI: 10.1029/2006 GB002836.
[3] 3Malca. J and Freire F (2006) Renewability and life-cycle energy efficiency of bioethanol and bio-ethyl
tertiary butyl ether (bio-ETBE): assessing the implication of allocat on. Energy 31,3362-3380.
[4] 4. Keimar, A and Sokhansanj, S.(2007) Switchgrass (Panium Vigratum) delivery to a biorefinery using
integrated biomass supply analysis and logistics (IBSAL) model. Bioresour.Technol.98, 1033-1044.
[5] 5. Lettens, S et al. (2003). Energy Budget and green house gas balance evaluation of sustainable coppice
systems for electricity production.Biomass Bioenergy 24,179-197
[6] 6Von Blottnitz, H and Curran, M (2007). A review of assessment conducted on bio-ethanol as a
transportation fuel from a net energy, green house gas and environmental life cycle perspective. J
Clean.Prod.15. 607-619
[7] 7.Pradhan A, D.S.Shrestha, A.McAloon, W.Yee, M.Haas, J.A. Duffield, A Nd H.Shapouri, 2009.Energy
life cycle assessment of soyabean biodiesel. Agriculture Economic Report No 845.
[8] 8.Source: Shares of each production type were obtained from the Oil & Gas Journal Database, using
numbers obtained in 1994. The Enhanced/Advanced category includes all advanced crude oil extraction
techniques except water flooding. It is assumed that steam flooding and CO2 injection will represent the
largest portion of the Enhanced/Advanced techniques obtained from the Oil & Gas Journal Database.
[9] 9 Sheehan,J, V.Camobreco.J.Duffield, M.Graboski and H.Shopouri,1998. Life Cycle inventory of
Biodiesel and petroleum diesel for use in an urban bus. NREL/SR-580-24089. Golden, Colo:National
renewable laboratory
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211
A Study of Select Aspects for Power
Grid Corporation of India Ltd
Surbhi Gupta
Amity University, Sector 125, Noida
ABSTRACT
Power Grid Corporation of India Limited (PGCIL), is an Indian state-owned electric utilities
company headquartered in Gurgaon, India. Power Grid wheels about 50% of the total power
generated in India on its transmission network. Power Grid has a pan-India presence with
around 95,329 km circuit of transmission network and 156 EHVAC & HVDC sub-stations with
a total transformation capacity of 138,673 MVA. The Inter- regional capacity is enhanced to
28,000 MW. Power Grid has also diversified into Telecom business and established a telecom
network of more than 25,000 km across the country. Power Grid has consistently maintained the
transmission system availability over 99.00% which is at par with the International Utilities. The
power sector in India is growing rapidly and the role of PGCIL is significant in this sector. The
sound financial health of the company would thus aid in achieving higher growth of the power
sector. It is always important to know the financial management practices prevalent in the
company. Thus, the present study would help us to know the financial management at PGCIL.
Ten year data, i.e., from 2002-12 would be taken for the study. This study would focus on
Liquidity analysis.
Keywords: Paired differences, Std. Error, Std. deviation, 95% Confidence Interval of the
difference, degree of freedom, two tailed test,t-test.
1. INTRODUCTION
Financial Management means planning, organizing, directing and controlling the financial
activities such as procurement and utilization of funds of the enterprise. It means applying general
management principles to financial resources of the enterprise. There are three elements of
financial management.
a. Investment decisions – They include investment in fixed assets (called as capital
budgeting). Investments in current assets are also a part of investment decisions called as
working capital decisions.
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A Study of Select Aspects for Power Grid Corporation of India Ltd
b. Financial decisions – They relate to the raising of finance from various resources which, in
turn, depend upon decision on type of source, period of financing, cost of financing and the
returns thereby
c. Dividend decisions – The finance managers are also required to take decision with regard
to the net profit distribution. Net profits are generally divided into two:-
Dividend for shareholders - Dividend and the rate of it has to be decided by the
company.
-
Retained profits - Amount to be retained depend upon expansion and diversification
plans of the enterprise.
The financial management is generally concerned with procurement, allocation and control of
financial resources of a concern. The objectives are:•
To ensure regular and adequate supply of funds to the concern.
•
To ensure adequate returns to the shareholders. This depends upon the earning capacity, market
price of the share and expectations of the shareholders.
•
To ensure optimum funds utilization. Once the funds are procured, they should be utilized in
maximum possible way at least cost.
•
To ensure safety on investment, i.e., funds should be invested in safe ventures so that adequate
rate of return can be achieved.
•
To plan a sound capital structure. There should be sound and fair composition of capital so that
a balance is maintained between debt and equity capital.
2. OBJECTIVE
The objective of the present study is to analyze the financial management of Power Grid
Corporation of India Ltd. (PGCIL), a Government of India Enterprise. PGCIL, is the Central
Transmission Utility (CTU) of the country under Ministry of Power and is one amongst the largest
power transmission utilities in the world. PGCIL is playing a vital role in the growth of Indian
power sector by developing a robust Integrated National Grid and associating in the flagship
programme of Govt. of India to provide “Power for all”. Innovations in technical and managerial
fields have resulted in coordinated development of power transmission network and effective
operation and management of regional and national grid. The primary objectives of study are:•
•
To study the financial health of PGCIL company.
To study the impact of recession in 2007-08 on the financial performance of PGCIL.
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Surbhi Gupta
3. RATIONALE
PGCIL is playing a strategic role in Indian Power Sector development by establishing and
maintaining the power transmission infrastructure which carries around 50% of total power
generated in the country. PGCIL has been instrumental in providing an efficient, reliable and
smooth grid operation and management in the country
The rationale behind the study is to examine the following major parameters:•
•
•
Enough funding is available at the right time to meet the needs of the business. In the short
term, funding may be needed to invest in equipment and stocks, pay employees and fund sales
made on credit. In the medium and long term, funding may be required for significant additions
to the productive capacity of the business or to make acquisitions.
Whether the business is meeting its objectives? Are assets being used efficiently? Are the
businesses assets secure? Does management act in the best interest of shareholders and in
accordance with business rules?
How the financing alternatives are being considered. For example, it is possible to raise finance
from selling new shares, borrowing from banks or taking credit from suppliers. Also, whether
profits earned by the business are being retained rather than distributed to shareholders via
dividends
4. LITERATURE REVIEW
Financial Management means the efficient and effective management of money (funds) in such a
manner as to accomplish the objectives of the organization. Financial management is an integral
part of overall management. It is concerned with the duties of the financial managers in the
business firm. The term financial management has been defined by Solomon, “It is concerned with
the efficient use of an important economic resource namely, capital funds”. Howard and Upton
define financial management “as an application of general managerial principles to the area of
financial decision-making. Weston and Brigham define financial management “is an area of
financial decision-making, harmonizing individual motives and enterprise goals”. Joshep and
Massie define financial management “is the operational activity of a business that is responsible for
obtaining and effectively utilizing the funds necessary for efficient operations. Thus, Financial
Management is mainly concerned with the effective funds management in the business.
Financial management provides a conceptual and analytical framework for financial decisions
making. The finance function covers both acquisitions of funds as well as their allocations. Thus,
apart from the issues involved in acquiring external funds, the main concern of financial
management is the efficient and wise allocation of funds to various uses.
Thus, financial management can be broken down into three major decisions as functions of finance:
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A Study of Select Aspects for Power Grid Corporation of India Ltd
i.
The investment decision,
ii.
The financing decision, and
iii.
The dividend policy decision.
Baker et.al., (2005) cites that investment decisions involve determining the type and amount of
assets that the firm wants to hold. That is, investing concerns allocating or using funds. The
financial manager makes investment decisions about all types of assets – items on the left-hand
side of the balance sheet. These decisions often involve buying, holding, reducing, replacing,
selling and managing assets. The process of planning and managing a firm’s long term investments
is called capital budgeting
Sheeba (2011) defines the financing decisions. Business activities require funds that are procured
from the financial markets from various sources like shareholders, debt-holders, financial
institutions and banks. Funds, like the other inputs of the organization, have to be procured at a
cost. Funds should be procured at a nominal cost and they should be effectively utilized to yield
maximum value. The finance manager is expected to design the best financial mix i.e., chose those
sources of finance where the cost of capital is minimal. The different sources of funds form the
basis of an organization’s capital structure.
Bhat (2009) states that dividend policy refers to the formation of a policy by the company
regarding the payment of dividend from profits to ordinary shareholders year to year. It determines
the ratio between dividend and retained earnings. The two important dimensions of dividend policy
are, what should be the dividend payout ratio? How stable should the dividends be over time? The
policy relating to dividend payout ratio and earnings retention varies not only from industry to
industry but also among companies within a given industry and within a given company from time
to time.
5. LIQUIDITY ANALYSIS
Liquidity analysis measures the ability of a firm to meet its short term maturing obligations (i.e.
current liabilities) as and when they fall due for payment. Investors often take a close look at
liquidity ratios when performing fundamental analysis on a firm. Since a company that is
consistently having trouble meeting its short-term debt is at a higher risk of bankruptcy, liquidity
ratios are a good measure of whether a company will be able to comfortably continue as a going
concern. In the normal course of business, these liabilities are paid out of current assets. An
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Surbhi Gupta
important aspect of liquidity analysis is to measure quality of debtors and inventories. This is
carried out through the liquidity ratios.
This paper is divided into three sections. Section I discusses about the two liquidity ratios i.e.
current ratio and acid test ratio for PGCIL over a period of ten years, 2002-2012. It is also
important to examine the quality of debtors and inventories. Turnover ratios help us to judge
whether debtors and inventories are slow or fast moving. Section II presents the debtors turnover
ratio and inventory turnover ratio of PGCIL over the ten year period. Concluding observations are
contained in Section III. It has to be examined whether subprime crisis and subsequent recession in
2007-08 had any impact on the liquidity of PGCIL. Therefore, the data is segregated into two
phases, namely 2002-03 to 2007-08 (pre-recession Phase-I) and 2008-09 to 2011-12 (postrecession Phase-II).
Section I
Current and Acid test ratios
Current ratio is a financial ratio that measures whether or not a firm has enough resources to pay its
debts over the next 12 months. It compares a firm's current assets to its current liabilities. Current
ratio is based on the assumption that all constituent items of current assets are homogeneous in
respect of liquidity. However, inventory and pre-paid expenses are least liquid assets and thus
current assets exclusive of these two items known as quick assets.
A more stringent liquidity ratio is acid test ratio which compares quick assets to its current
liabilities.The objective of this section is to examine the liquidity ratios of PGCIL over the ten year
period; i.e. from 2002-12 in terms of employment of current liabilities. The following bases have
been used to arrive at the liquidity ratios:Current ratio = Current assets / Current liabilities
(1)
Acid test ratio = (Current assets – inventory – pre-paid expenses) / Current liabilities
(2)
TABLE 1: CURRENT RATIO AND ACID TEST RATIO OF PGCIL, 2002-12
Year
2002-03
2003-04
2004-05
2005-06
2006-07
Current ratio
1.69
1.23
0.93
0.57
0.54
Acid test ratio
1.6
1.14
0.86
0.53
0.52
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A Study of Select Aspects for Power Grid Corporation of India Ltd
2007-08
2008-09
2009-10
2010-11
2011-12
Mean (2002-03 to 2007-08)
Mean (2008-09 to 2011-12)
Mean (2002-03 to 2011-12)
Median (2002-03 to 2007-08)
Median (2008-09 to 2011-12)
Median (2002-03 to 2011-12)
0.75
0.64
0.71
0.77
0.99
0.95
0.78
0.88
0.84
0.74
0.76
0.71
0.61
0.69
0.74
0.96
0.89
0.75
0.84
0.79
0.72
0.73
Paired Sample Test
Paired Differences
t
df
Mean Std.
Std. Error95%
Error
Confidence
Deviation Mean
Interval
of
the
Difference
Lower
Upper
Pair 1 Pre-Recession
.02121 .01500 -.03559 .34559
1
– Post-Recession
.15500
10.333
Sig. (2tailed)
.061
Figure 1: Current Ratio and Acid Test Ratio of PGCIL, 2002-12
2002
From Table 1 and Figure 1, it can be observed that the current ratio during pre-recession
pre
phase-I
was 0.95, which declined to 0.78 during post-recession
recession phase-II.
phase
On similar terms, the acid test
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Surbhi Gupta
ratio also declined. Current ratio of less than 1 is a serious concern, since it implies there is no
safety margin and the firm is not able to meet its short term obligations. However, on a positive
note it can be seen from data that the current ratio/acid test ratio has increased to the level of one by
year 2011-12. This would have given confidence to the short term lenders and creditors, that there
investment are safe and secure.
From Table 1, it can be inferred that there is no statistically significance between the pre-recession
phase and post-recession phase on account of current and acid test ratios.
Section II
Turnover ratios The objective of this section is to examine the turnover ratios. These ratios
determine how quickly certain assets are converted to cash. A high turnover ratio is a sign that the
company is producing and selling its goods or services very quickly. The following bases have
been used to arrive at the turnover ratios:Debtors turnover ratio = Net credit sales / Average debtors
(3)
Inventory turnover ratio = Cost of goods sold / Average finished goods inventory
(4)
TABLE 2: DEBTORS TURNOVER RATIO AND INVENTORY TURNOVER RATIO OF
PGCIL, 2002-12
Year
2002-03
2003-04
2004-05
2005-06
2006-07
2007-08
2008-09
2009-10
2010-11
2011-12
Mean (2002-03 to 2007-08)
Mean (2008-09 to 2011-12)
Debtors turnover
ratio
1.29
2.12
5.37
8.10
8.80
5.80
5.32
3.97
3.12
3.66
5.25
4.02
Inventory turnover
ratio
13.09
13.43
15.43
19.34
21.45
17.24
19.68
20.67
21.99
22.79
16.66
21.28
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A Study of Select Aspects for Power Grid Corporation of India Ltd
Mean (2002-03 to 2011-12)
Median (2002-03 to 2007-08)
Median (2008-09 to 2011-12)
Median (2002-03 to 2011-12)
4.76
5.59
3.82
4.65
18.51
16.34
21.33
19.51
Paired Samples Test
Paired Differences
t
df
95%
Confidence
Mean Std.
Std. Error Interval
of
the
Deviation Mean
Difference
Lower
Upper
Pair 1 Pre-Recession
– Post-Recession
4.13657 2.92500 -38.86065 35.47065 -.579 1
1.6950
0
Sig.
(2-tailed)
.666
Figure 2: Debtors Turnover Ratio and Inventory Turnover Ratio of PGCIL, 2002-12
2002
The debtors turnover ratio of PGCIL averages 4.76 during the ten year period, 2002-12.
2002
This
means that the debtors collection period is 77 days (=2.5 months). The inventory holding period
averages 20 days for past ten years for PGCIL.
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Surbhi Gupta
SECTION-III
Concluding Observations
This chapter analyzed the liquidity ratios of PGCIL over the period of ten years, 2002-12. It can be
observed from the analysis that the current ratio and the acid test ratios of PGCIL are at alarming
level. This situation warrants immediate remedial action for infusing positive sentiments to the
short term lenders / creditors. The higher the turnover ratios, the better it is. This can be understood
from the fact that companies with low profit margins tend to have high asset turnover, while those
with high profit margins have low asset turnover. Recession during 2007-08, had no effect on
PGCIL liquidity, as can be seen from the analysis.
REFERENCES
[1] Baker, H. Kent and Gary Powell, (2005), Understanding Financial Management: A Practical Guide
(Blackwell Publishing), pp (5-6).
[2] Kapil, Sheeba, (2011), Financial Management: A Practical Guide, (Pearson Publishing), pp (2-3).
[3] Bhat, Sudhindra, (2009), Financial Management: Principles and Practice, (Excel Books), p. 534.
[4] Paramasivan, C. and T. Subramanian, (2009), Financial Management, (New Age International (P) Ltd.
Publishers), p. 3.
[5] Joy O. M. (1977), Introduction to Financial Management, (Irwin, Homewood), pp. (2-74).
[6] Lintner, J., (1956 ), “Distribution of Income of Corporations among Dividends, Retained Earnings and
Taxes”, American Economic Review, pp (97-113).
[7] Soloman, E, (1969), Theory of financial Management, (Columbia University Press, New York), p. 8.
[8] Khan, M. Y. and P .K. Jain, (2008), Financial Management – Text, Problems and Cases, (Tata McGraw
Hill Publishing Co., New Delhi), p. 1.7
Websites:
[1] Power Grid Corporation of India Ltd., http://www.powergridindia.com
[2] National Stock Exchange, http://www.nseindia.com
[3] Money Control, http://www.moneycontrol.com
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A Fully-Integrated Switched-Capacitor Voltage Converter
with higher Efficiency at Low Power
Swati Singh, Uma Nirmal
1,2
Mody University of Science & Technology, Laxmangarh (Sikar), Rajasthan, India
ABSTRACT
DC-DC converters are also known as switching voltage regulators, are one of the main
component of a power management unit. Their main role is to provide a constant, smooth output
voltage to power the electronic devices. Switching mode DC-DC converters are critical building
blocks in portable devices and hence their efficiency and power are a major issue. This paper
describes design techniques to maximize the efficiency of fully integrated switched-capacitor
(SC) DC-DC converters. The measured performance of switched capacitor converter
implemented on tanner EDA tool at 45 nm and 90nm CMOS technology with 2V input voltage to
support output voltages of .5 and .7 and achieves 94% and 98% efficiency at an output power
86.9uW and 0.175mW .
Keywords- DC-DC conversion, switched-capacitor, switching converter
1. INTRODUCTION
Every Electronic circuit is assumed to operate some supply voltage which is usually assumed to be
constant in nature. A voltage regulator is a power electronic circuit that maintains a constant output
voltage irrespective of change in load current or line voltage. Many different types of voltage
regulators with a variety of control schemes are used. With the increase in circuit complexity and
improved technology a more severe requirement for accurate and fast regulation is desired. This
has led to need for newer and more reliable design of dc-dc converters. The dc-dc converter inputs
an unregulated dc voltage input and outputs a constant or regulated voltage. The regulators can be
mainly classified into linear and switching regulators shown in fig-1. All regulators have a power
transfer stage and a control circuitry to sense the output voltage and adjust the power transfer stage
to maintain the constant output voltage. A DC-DC converter is a device that accepts a DC input
voltage and produces a DC output voltage. Typically, the output produced is at a different voltage
level than input. Portable electronic devices, such as cell phones, PDAs, pagers and laptops, are
usually powered by batteries. After the battery has been used for a period of time, the battery
voltage drops depending on the types of batteries and devices. This voltage variation may cause
some problems in the operation of the electronic device powered by the batteries. So, DC-DC
converters are often used to provide a stable and constant power supply voltage for these portable
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Swati Singh, Uma Nirmal
electronic devices. According to the components used for storing and transferring energy, there are
two main kinds of topologies in DC/DC converters: inductive converters and
an switched capacitor
converters. The inductive converter using inductor as energy storing and transferring component
has been a power supply solution in all kinds of applications for many years. It is still a good way
to deliver a high load current over 500mA.
0mA. But in recent years, since the size of portable electronic
device is getting smaller and smaller, and the load current and supply voltage are getting lower and
lower, the inductor less converters based on switched capacitor are more and more popular in
i the
space constrained applications with 10mA to 500mA load current. Such converters avoid the use of
bulky and noisy magnetic components, inductors.
2. TYPES OF DC-DC CONVERTER
DC-DC
DC converter are a kind of converters which convert unregulated DC power to regulated DC
power. The basic configuration of DC-DC
DC converters areare
•
Buck Converter- Buck converter is made of voltage source, voltage controlled switch, flywheel
diode, inductor, capacitor and load . A control circuit is connected between the base of
MOSFET
ET and one of the plates of capacitor. It is called the buck converter because the voltage
across the inductor bucks or opposes supply voltage. In this converter the output voltage is
normally less than the input voltage.[1,2]
DC-DC
Converters
Switch mode
converter(SMC)
Magnetic SMC
Linear
Converter
Capacitive SMC
Fig1-Classification
Classification of converters
conv
Boost Converter-The
The boost converter has similar structure as the buck converter, but has
components arranged in different manner. It is called boost converter because the voltage across
inductor adds to the input supply voltage to boost the voltage above input voltage. The output of
boost is always greater than input voltage[1,2].
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A Fully-Integrated Switched-Capacitor Voltage Converter with higher Efficiency at Low Power
•
•
•
Buck-Boost Converter-The components in buck-boost converter are MOSFET, diode, inductor
and capacitor similar to buck and boost converter. The components are arranged in different
way to provide step up as well as step down with polarity reversal or inversion as well[1,2].
Cuk Converter-The buck, boost and buck-boost converters all transfer energy between input
and output using the inductor, thus building the voltage across the inductor. The cuk converter
transfers energy through the capacitor thus the analysis is based on current through the
capacitor. The output is inverted as in the buck-boost converter whereas the circuit
configuration is a combination of buck and boost converters[1,2].
Switched Capacitor Converter-These converters exclusively comprised of only switches and
capacitors to efficiently convert one voltage into another. They have smaller size than inductor
based converters[3].
3. SWITCHED CAPACITOR DC-DC CONVERTER
Switched capacitor converters become popular for on-chip power conversion since there is no
inductive component present, which on-chip with sufficiently low losses are large and difficult to
manufacture, are required. They uses only switches and capacitor. Consider the circuit shown in
fig-2, consisting of only switches and capacitors. The switches in the circuit are operated by two
distinct non-overlapping clock signal, ῆ1 and ῆ2, so that switches turn on when the clock signal is
high. During phase 1 (ῆ1), the charge-transfer capacitors (CT )get charged from the battery (VIn). In
the phase2 (ῆ2) of the clock, they dump the charge gained onto the load (VL).
This paper presents the design and evaluation of a 2:7 and 2:5 voltage ratio down conversion
switched capacitor converter shown in implemented in 45nm and 90nm technology on tanner tool.
During the operation of SC topologies 2:7 and 2:5,these topologies switch into the circuit
depending upon the load and input voltage requirements shown in fig-3. During the clock signal
a=high ,load capacitor CL is charged from battery voltage, through charge transfer capacitors.
Similarly when clock signal b=high ,charge accumulated by charge transfer capacitor is transferred
to load capacitor by connecting them together shown in fig-3. Different capacitor arrangement in
SC topology results in the unique no-load voltage at the output . During the closed loop operation
of SC converter, these topologies will be configured in the main switching matrix based on the
input voltage range and output voltage. If the output voltage falls below a certain value for a certain
topology, a higher topology is needed to meet up load current requirement.
4. DESIGN AND IMPLEMENTATION
This section discusses the design and implementation of the 2:7 and 2:5 SC converter integrated in
a 45nm and 90nm technology. In this work the demonstration of high efficiency voltage conversion
is done by using the circuit shown in fig-4. In 2:7 and 2:5 conversion the output voltage is lower
than the input voltage . In Phase-1 the capacitors C1, C2, C3,C4(2:7 conversion) and C1,C2,C3(2:5
conversion)charges and current flows into the Vout.
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Swati Singh, Uma Nirmal
Fig 2:Basic working of SC DC-DC
DC
converter
In the Phase-2,
2, the capacitor discharges towards the output voltage. Thus, charge
charg is delivered to the
load in each switching cycle. While an inherent output ripple may exist, a multi-phase
multi
system with
sufficient decoupling capacitance minimizes this effect. In a step-down
step
converter which are
intended to generate output voltages near the
he nominal process voltage, then the breakdown voltage
of these switches will most likely to be smaller than the input voltage VBAT, and therefore
appropriate switch driving strategies are needed. Therefore a differential ring oscillator is used to
meet the requirement of clock generation.
(a)
(b)
Fig3-(a)2:7
(a)2:7 Topology of SC converter (b)2:5 Topology of SC converter
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A Fully-Integrated Switched-Capacitor Voltage Converter with higher Efficiency at Low Power
The output of ring oscillator is used to drive two different phases of SC converter topologies. The
output of ring oscillator is applied to AND gate with enable. here AND gate is designed because it
provides buffering to the clock generator and clock produce with sharper edges, it also provides
additional control from outside for enabling/disabling the clock generator .Some transistor in SC
stage require different clock voltage to operate . This poses the requirement of level shifter[4]
which can shift the voltage level of Vdrive to GND. here Vdrive is the optimum value of gate to source
voltages at which the efficiency is higher. This circuit for both topologies is simulated for current
and power dissipation for different values of frequency on different technologies such as 45nm and
90nm. Simulated figures are depicted from fig-5 to fig-8. Here it is shown that 2:7 topology gives
better efficient result on 90nm technology i.e. 94% and 2:5 gives 98% efficiency on 45nm
technology each of them at 2v supply. Summary of work is shown in table-1.
100
80
60
40
20
0
45
50
55
60
Output Voltage(mV)
Power(uW)
Fig4- Converter power switch control circuit
540
520
500
480
460
440
420
400
45
Frequency(MHz)
50
55
60
Frequency(MHz)
(a)
(b)
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Efficiency(%)
Swati Singh, Uma Nirmal
100
90
80
70
45
50
55
60
Frequency(MHz)
(c)
100
Output Voltage(mV)
Power(uW)
fig5--(a)Power v/s frequency (b) Output Voltage V/s Frequency (c)Efficiency v/s Frequency
on 45nm technology for 2:7 topology
50
0
45
50
55
60
Frequency(MHz)
(a)
600
400
200
0
45
50
55
60
Frequency(MHz)
(b)
Efficiency(%)
100
80
60
40
20
0
45
50
55
60
Frequency(MHz)
(c)
Fig6-(a)Power v/s frequency (b) Output Voltage V/s Frequency (c)Efficiency v/s Frequency
on 90nm technology for 2:7 topology
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A Fully-Integrated Switched-Capacitor Voltage Converter with higher Efficiency at Low Power
900
800
700
600
500
400
300
200
100
0
Output Voltage(mV)
Power(mW)
0.15
0.1
0.05
0
20
25
30
35
40
45
Frequency(MHz)
20
(a)
25
30
35
40
Frequency(MHz)
45
(b)
120
Efficiency(%)
100
80
60
40
20
0
20
25
30
35
Frequency(MHz)
40
45
(c)
Fig7--(a)Power v/s frequency (b) Output Voltage V/s Frequency (c)Efficiency v/s Frequency
on 45nm technology for 2:5 topology
Output Voltage(mV)
Power(mW)
0.2
0.15
0.1
0.05
0
20
25
30
35
40
1000
800
600
400
200
0
20
45
25
30
35
40
45
Frequency(MHz)
Frequency(MHz)
(a)
(b)
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Swati Singh, Uma Nirmal
120
Efficiency(%)
100
80
60
40
20
0
20
25
30
35
40
45
Frequency(MHz)
(c)
Fig8---(a)Power v/s frequency (b) Output Voltage V/s Frequency (c)Efficiency v/s Frequency
on 90nm technology for 2:5 topology
Table1- Summary of the 2:7 and 2:5 Converter
Topology
2:7
2:5
Process
45nm
Tool
Input Voltage
2v
2v
2v
2v
Output
Voltage
0.532v
0.534v
0.786v
0.783v
Power
81.5uW
86.9uW
0.1352mW
0.1565mW
Frequency
60MHz
60MHz
45MHz
45MHz
Efficiency
92%
94%
98%
97%
Tanner
90nm
Tool
Tanner
45nm
Tool
Tanner
90nm
Tool
Tanner
5. COMPARISON AND RESULT
In Table. 2, the results presented in this paper are compared to previously published results on SC
converters focusing on efficiency. This work is implemented on 90nm and 45nm Technology on
Tanner EDA Tool and it gives
98% efficiency at low power for 2:5 topology on 45nm.
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A Fully-Integrated Switched-Capacitor Voltage Converter with higher Efficiency at Low Power
Table-2 Comparison of the work presented in this paper to previously published work
Reference
Technology
[5]
45nm SOI
[6]
90nm BULK
Topology
Input Voltage
Output Voltage
Power
Frequency
Efficiency
2:1
2V
0.95V
2.6mV
100MHz
90%
2:1
2.4V
1V
1650mW
N/A
69%
[This work]
45nm and 90nm Tanner
EDA Generic
2:7 and 2:5
2V
0.78(2:5on 45nm)
135.2uW(2:5 on 45nm)
45MHz(2:5on 45nm)
98%(2:5on 45nm)
6. CONCLUSION
In this paper 2:5 and 2:7 topologies are simulated on 90nm and 45nm technology on Tanner EDA
Tool. This work shows the better efficient result on 45nm technology for 2:5 topology when input
voltage is 2V at 45MHz frequency which results in 0.78V output voltage,135.2uW power and 98%
efficiency .
REFERENCES
[1] H.Knopf," Analysis, simulation and evaluation of maximum power point tracking method for a solar
power vehicle," in Electrical and computer Engineering, vol. Master of Science in Electrical and
computer Engineering: Portland State University 1999, pp.177 .
[2] T.S.USTUN and S.Mekhilef, "Effects of a Static Synchronous Series Compensator(SSSC) Based on Soft
[3] Switching 48 pulse PWM Inverter on the Power demand From the Grid."Journal of Power Electronics,
vol.10,pp.113
[4] R.Yokesh K, C.Anantha P, "Voltage Scalable Switched DC-DC Converter For Ultra Low Power on
ChipApplication," IEEE Conf, Power Electronics Specialist, pp2353-2359, 2009
[5] Hanh-Phuc, Seth R, Sanders, Elad Alon,"Design Technique for fully Integrated Switched Capacitor DCDC Converter," IEEE J.Solid state Circuits, Vol 46,no9,pp.2120-2131,2011
[6] L.Chang,, R.K.Montoye, B.L.Ji, A.J.Weger, K.G.Stawiasz and R.H.Dennard,"A Fully Integrated
Switched Capacitor 2:1 Voltage Converter with Regulation capability and 90% Efficiency at
2.3A/mm2,"IEEE symp on VLSI Circuits/ Technical Digest of Technical Papers, pp55-56,2010
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Preparation of CuInS2 and In2S3 Thin Film for Thin
Film Solar Cell Application Using Chemical Spray
Pyrolysis Technique
T Krishna Teja1 , Karthigeyan2
1
Mtech (Nanotechnology), SRM University , Chennai , Tamilnadu
Department of Physics and Nanotechnology, SRM University , Chennai , Tamilnadu
2
ABSTRACT
In recent years, the field of photovoltaic has become increasingly important due to rising energy
demand and climate change. In particular, thin films of CuInS2 are promising solar absorber
materials due to their high efficiencies and low required thicknesses. In this work, CuInS2 and
In2S3 Thin film deposited onto glass substrate by chemical spray pyrolysis techniques as a route
to low-cost and high-throughput for solar cell preparation. Thin films were deposited by
changing molar concentrations of the CuInS2 and also Temperature. Structural, chemical
composition and optical properties of CuInS2 and In2S3 thin films were analyzed by X-ray
diffraction, Atomic force microscopy, Hall Effect measurement and UV-Visible spectroscopy.
The crystalline size for the CuInS2 thin film corresponding to the (112) orientation is 67.74nm.
The optical band gap Eg values of sprayed CuInS2 films deposited at temperatures below 350 °C
is 1.87eV. The optical band gap Eg values for In2S3 thin film on glass is 2.83eV.
Keywords: Thin film, band gap, chemical spray pyrolysis.
1. INTRODUCTION TO THIN FILMS
With combination of chemical, physical and mechanical, properties has changed the modern
society. There is an increasing technological progress. Thin film materials are the key elements of
continued technological advances made in the fields of optoelectronic, photonic, and magnetic
devices. The processing of materials into thin films allows easy integration into various types of
devices.
The properties of material significantly differ when analyzed in the form of thin films. Most of the
functional materials are rather applied in thin film form due to their specific electrical, magnetic,
optical properties or wear resistance. Thin film technologies make use of the fact that the properties
can particularly be controlled by the thickness parameter. Thin films are formed mostly by
deposition, either physical or chemical methods. Thin films, both crystalline and amorphous, have
immense importance in the age of high technology.
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Preparation of CuInS2 and In2S3 Thin Film for Thin Film Solar Cell Application Using Chemical Spray
Pyrolysis Technique
2. CHALCOPYRITE BASED SOLAR CELLS
Chalcopyrite based solar modules uniquely combine advantages of thin film technology with the
efficiency and stability of conventional crystalline silicon cells. It is therefore believed that
chalcopyrite based modules can take up a large part of the photovoltaic (PV) market growth .Once
true mass production is started. The most important chalcopyrite compounds for photovoltaic
applications are CuInSe2, CuInS2, and CuGaSe2 with bandgaps of 1.0, 1.5, and 1.7 eV,
respectively. Together with related materials they offer high optical absorption and a wide range of
lattice constants and bandgaps. The compounds can be alloyed to obtain intermediate bandgaps.
Starting with single crystals, chalcopyrite based solar cells have been under investigation since
1974. The first chalcopyrite cells had a CuInSe2 absorber and therefore the technology is most
advanced for lower gap materials with a composition close to CuInSe2. Today the efficiency of lab
scale thin film devices is close to 20% efficiency comparable to the best multicrystalline silicon
cells. Many scaling up and manufacturing issues have been resolved.
3. EXPERIMENTAL METHODOLOGY
Here, we adopted chemical spray pyrolysis method to deposit CuInS2 and In2S3 Thin films on a
glass substrate by varying different Molar ratios, temperatures and different values of compressed
air pressure.
4. PREPARATION OF CUINS2 THIN FILM ON GLASS SUBSTRATE
Copper indium sulphide (CuInS2) Thin films were deposited by a chemical spray pyrolysis method
onto the glass substrates. First, we need to prepare Aqueous solutions of copper chloride (CuCl2) of
100ml-1M, by taking 13.445grams of CuCl2 powder in 100ml di-water and we need to
ultrasonicate the above solution for 10min, after that the solution is pour into a glass beaker
through filter paper using glass funnel And Then Aqueous solution of Indium chloride (InCl3) of
100ml- 0.1M is prepare by taking 2.211grams of InCl3 powder in 100 ml di-water and we need to
ultrasonicate the above solution for 10 min, after that the solution is pour in to glass beaker through
filter paper using glass funnel and Then Aqueous solution of thiourea(CH4N2S) of 100ml- 1M
solution is prepare by taking 7.612grams of CH4N2S powder in 100ml di-water and we need to
ultrasonicate the above solution for 10min, after that the solution is pour into a glass beaker
through filter paper using glass funnel.
After making ready of above three solutions, we prepared precursor solution by varying different
Molar ratios i.e., CuCl2:InCl3:CH4N2S is taken in 1:1:8 ratio (i.e. 500µl-CuCl2, 5ml-InCl2, 4mlThiourea) and 1:1:10 ratio (i.e. 500µl-CuCl2, 5ml-InCl2, 5ml-Thiourea) in 100ml di-water.
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T Krishna Teja, Karthigeyan
Note 1: As per the stoichiometry equation we need to take Cu: In: S2 in 1:1:2 ratio, But in my
observation the better film were deposited on glass substrate in 1:1:8 and 1:1:10 ratio, when
compare 1:1:2 and 1:1:5(i.e. we absorbed more pin holes through naked eyes).
Note 2: Thiourea should be taken last when we are preparing precursor solution (i.e., at the time
loading the precursor solution in precursor solution beaker in spray pyrolysis equipment, because
we observed white like substance are formed when we add thiourea first in to the di-water.
Here, we are using 1mm thickness glass as substrate .The glass substrates are cut into 1.5 cm × 2
cm space area. Then are taken in Iso-Propanol and ultrasonicate for 10min, in order to keep the
glass substrates clean. So, directly we can place this glass substrate on heater.
5. EXPERIMENTAL SETUP OF CHEMICAL SPRAY PYROLYSIS EQUIPMENT:
Before spraying the precursor solution onto substrate we need to set the parameters of the chemical
spray pyrolysis equipment such as heater temperature (-in order to heat the surface of the
substrate), flow rate (- which help to set the flow of the solution ml\min), flow factor (-if any error
in flow rate we can set it by setting value of flow rate), compressed air pressure kg/cm2 (-it helps to
pulverize the spray solution) and x-axis and y-axis of spray nozzle is controlled through the system
program (-through xy-position control software).The important thing we need to set when we start
spraying is distance between spray nozzle and the substrate. Here we kept 19 cm distance from
spray nozzle to substrate (-it plays a major role in deposition of thin film thickness).After that we
need to set the program in system software in order to monitor the movement of the spray nozzle in
to our desired positions, not only direction we can also set the speed of the nozzle movement. The
cleaned glass substrates are kept on heater surface in order to get the substrate heat. The precursor
solution was sprayed in air onto glass substrates heated at different temperatures between 340°C
and 350°C, with different compressed air pressure values 1.8 and 2.5 kg/cm2, in order to pulverize
the solution (Note: here if we keep air pressure below this air pressure values, due to less air
pressure the spray droplets that are depositing on substrates are large, So deposited film in not good
i.e. grain like structures appears on film through naked eye). Here we used spray rate of 6ml\min (by changing different flow rates we absorbed the films that are deposited, in 6ml\min we find better
thin deposition on substrate).Films thickness and roughness was measured by AFM. The structural
properties of these films were characterized by X-ray diffraction. Optical properties were
monitored by absorbance using UV-Visible spectroscopy.
6. PREPARATION OF IN2S3 THIN FILM ON GLASS SUBSTRATE
Indium sulphide (In2S3) Thin films were deposited by a chemical spray pyrolysis method onto the
glass substrates. First, Aqueous solutions of Indium chloride (InCl2) of 100ml- 0.1M and thiourea
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Preparation of CuInS2 and In2S3 Thin Film for Thin Film Solar Cell Application Using Chemical Spray
Pyrolysis Technique
of 100ml- 1M is prepared. By taking the indium/sulphur molar ratio in 1:10 (i.e. 5ml-InCl2, 5mlThiourea) in 100ml Di-water precursor solution is prepared. Here, we are using 1mm thickness
glass as a substrate. The glass substrates are taken in Iso-Propanol and ultrasonicate for 10min, in
order to keep the glass substrates clean. Then, the solution was sprayed in air onto glass substrates
heated at temperatures between 350°C , with compressed air pressure values 1.8 kg/cm2, in order
to pulverized the solution we need compressed air and using spray rates of 1 ml min−1. Films
thickness and roughness was measured by AFM. The structural properties of these films were
characterized by X-ray diffraction. Composition percentage analysis is performed by using energy
dispersive X-ray Analysis (EDAX). Optical properties were monitored by absorbance using UVVisible spectroscopy. Electrical properties were measured by Hall Effect equipment.
7. RESULTS AND DISCUSSIONS
XRD :
CuInS2 and In2S3on Glass XRD :
a
b
(2
600
7)
1
(2
400
400
(3
300
0
3)
2
1)
(2
200
Intensity
500
1
7)
1)
(3
300
(1
2 12)
1
In2S3 on glass
1)
500
(1
(2
600
In2S3 on glass
(2
Intensity
1
0
3)
1)
(2
200
100
2
2 12)
100
10
20
30
40
50
2 Theta (deg)
60
70
80
90
10
20
30
40
50
60
70
80
90
2 Theta (deg)
Fig1(a); XRD graph for CuInS2 on glass Substrate, b) XRD Graph for In2S3 on glass
substrate.
Above fig 1(a) shows the XRD graph for CuInS2 thin film deposited on glass substrate. The
obtained XRD pattern was matched with JCPDS No. 032-0339. The 1:1:10 ratio of Cu:In:S2 is
deposited on glass substrate temperature at 350 ºC . The average size of crystallite is estimated by
Scherrer’s formula. The crystalline size for the CuInS2 corresponding to the (112) orientation is
67.74nm. As the width of the diffraction peak increases, the crystalline size of the sample
decreases. Fig.1(b) shows the XRD peaks corresponding to (103) , (211), (217) , (321) and (2212)
planes of In2S3 clearly observed. The crystalline size for In2S3 on glass substrate for corresponding
planes is 17.59nm, 67.4nm, 23.89nm, 14.86nm, 38.31nm. The d values coincides of In2S3 peaks
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T Krishna Teja, Karthigeyan
were coincides with standard JCPDS data (025-0390 ). The intensity of peak corresponding to
(217) plane was observed to be much greater than that of other peaks present, indicating a strong
orientation on the (217) plane. The higher intensity peak and FWHM of diffraction peak is very
small shows the improvement in crystalanity.
8. OPTICAL PROPERTIES:
CuInS2 on Glass substrate:
b
a
4.0
CIS on glass
7.00E+026
3.5
Tauc Plot CIS on Glass
6.00E+026
3.0
2
-2
2
(α hν ) cm eV
Absorbance (a.u.)
5.00E+026
2.5
2.0
1.5
1.0
Eg=1.87eV
4.00E+026
3.00E+026
2.00E+026
1.00E+026
0.5
0.00E+000
0.0
500
1000
1500
Wavelength (nm)
2000
2500
-1.00E+026
0
1
2
3
4
5
6
7
hν (eV)
Fig 2(a) : Absorbance Vs Wavelength for CuInS2 on Glass substrate , b) Relationship
between (αhν)2 and photon energy (hν) of CuInS2 sprayed thin films.
Fig2(a) shows the absorbance Vs wavelength graph. The absorption coefficient and the optical
band gap values were determined from transmission data.
Fig 2(b) gives the Eg values corresponding to direct band gap transitions were deduced from the
(αhν)2 versus the photon energy hν plots extrapolating the straight line from the relatively high
absorption region conforming to the well-known Tauc law
(αhν )1/n = A( hν−Eg)
where A is a constant related to the effective masses of charge carriers, h is the Planck constant, Eg
is the band gap energy, hν is the incident photon energy, and1/n is the exponent that depends on the
nature of the optical transition (n=0.5 and 2 for direct and ndirect transition, respectively). Eg
values of sprayed CuInS2 films deposited at temperatures below 350 °C is 1.87eV.
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Preparation of CuInS2 and In2S3 Thin Film for Thin Film Solar Cell Application Using Chemical Spray
Pyrolysis Technique
Optical property for In2S3
4.0
1.60E+020
InS2 on glass
1.40E+020
3.5
1.20E+020
3.0
Eg=2.83
1.00E+020
eV
2
2.5
-2
8.00E+019
cm
2.0
ν2
6.00E+019
1.5
(α h )
Absorbance (a.u.)
Tauc Plot for In 2 S 3 on glass
4.00E+019
1.0
2.00E+019
0.5
0.00E+000
0.0
-2.00E+019
500
1000
1500
2000
2500
1
Wavelength (nm)
2
3
4
5
6
7
h ν (eV)
Fig 3(a): Absorbance Vs Wavelength for In2S3 on Glass, b) Relationship between (αhν)2 and
photon energy (hν) of In2S3 thin films on glass.
The Eg values corresponding to direct band gap transitions were deduced from the (αhν)2 versus
the photon energy hν plots extrapolating the straight line from the relatively high absorption region
conforming to the well-known Tauc law . The Eg values for In2S3 thin film on glass is 2.83eV.
Atomic force microscopy :
a
b
Fig 4(a); AFM 3D image for CuInS2 on Glass Substrate , b) AFM 3D image for In2S3 on Glass
Substrate.
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T Krishna Teja, Karthigeyan
Fig 4(a) gives the AFM 3D image for CuInS2 on glass substrate. The CuInS2 on Glass Substrate
film is well covered to the substrate surface. Average roughness is 20nm. Fig 4(b) gives the AFM
3D image for In2S3 on glass substrate, It shows that the film is well covered to the substrate surface.
Average roughness is 5nm.
9. CONCLUSION
The obtained XRD pattern was matched with JCPDS No. 032-0339. The 1:1:10 ratio of Cu:In:S2 is
deposited on glass substrate temperature at 350 ºC . The crystalline size for the CuInS2
corresponding to the (112) orientation is 67.74nm. As the width of the diffraction peak increases,
the crystalline size of the sample decreases. The crystalline size for In2S3 on glass substrate is
17.59nm, 67.4nm, 23.89nm, 14.86nm, 38.31nm. The d values coincides of In2S3 peaks were
coincides with standard JCPDS data (025-0390 ). The higher intensity peak and FWHM of
diffraction peak is very small shows the improvement in crystallinity. The Eg values for CuInS2 on
glass substrate to direct band gap transitions were deduced from the well-known Tauc law. Eg
values of sprayed CuInS2 films deposited at temperatures below 350 °C is 1.87eV. The Eg values
for In2S3 thin film on glass is 2.83eV. AFM 3D images for CuInS2 on Glass Substrate film is well
covered to the substrate surface. Average roughness is 20nm. Average roughness for In2S3 on glass
Substrate is 5nm. Further electrical properties study of thin film is needed and fabrication of solar
cell will be doing in future work.
REFERENCES
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
Katerski, M. Danilson, et,al.,2010, Energy Procedia 2 (2010) 103–107
M. Sahal ῆ, B. Marí, M. Mollar, Thin Solid Films 517 (2009) 2202–2204
M. Krunks, O. Bijakina, V. Mikl,et,al, Solar Energy Materials & Solar Cells 69 (2001) 93}98
M. Krunksa, O. Kijatkinaa, H. Rebane, et.al,., Thin Solid Films 403 –404 (2002) 71–75
Pramod S. Patil, Materials Chemistry and Physics 59 (1999) 185±198
Angel Susan Cherian a, K.B. Jinesh b, Y. Kashiwaba et,al,., Solar Energy 86 (2012) 1872–1879
Teny Theresa Johna, Meril Mathewa,et,al,., Solar Energy Materials & Solar Cells 89 (2005) 27–36
P.K. Nair*, M.T.S. Nair, V.M. Garcõ«a,et,al,., Solar Energy Materials and Solar Cells 52 (1998)
313Ð344
[9] G. E. Patil,1 D. D. Kajale,et,al,., International Scholarly Research Network ISRN Nanotechnology
Volume 2012, Article ID 275872
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236
Study of Nanoporous Silica Aerogel Composite for
Architectural Thermal Insulation Application
Thanuja M Y1, Karthigeyan2
1
Mtech (Nanotechnology), SRM University, Chennai, Tamilnadu.
Department of Physics and Nanotechnology, SRM University, Chennai, Tamilnadu.
2
ABSTRACT
Silica aerogel is a nanostructure material with high specific surface area, high porosity, low
density, low dielectric constant and excellent heat insulation properties. In this work, silica
aerogel was incorporated in the building material such as cement and white cement to prepare
lightweight material with thermal insulating property. Synthesis of Silica Aerogel has been
carried out in sol-gel methods. However the sol-gel synthesis method is a fast and efficient
method which can be easily carried out on a laboratory scale. Silica Aerogel was prepared using
TEOS as precursor, Ethanol, water, ammonia and ammoniumflouride by two step process
followed by sol-gel process and supercritical drying process. Characterization of the Silica
Aerogel was carried out by BET Analysis to know the porosity. Cement and white cement
composites were prepared by varying the loading of silica aerogel. Mixing of silica aerogel with
cement and white cement were carried out by mechanical mixing. Composites were dried under
ambient condition. Characterization of the composites was carried out by BET, Density of
composites was calculated , compressive strength of the composites were tested to know the
strength of the composited by increases in loading of silica aerogel. Thermal insulation testing
was carried to know the insulating property of the composites.
Keywords: Silica aerogel , thermal insulation property , Nanoporous ,
1. INTRODUCTION
Silica aerogels are nanoporous materials with unusual properties such as light weight , high specific
surface area (500-1200 m2/g), high porosity (80-99.8%), low density (~0.03 g/cm3), high thermal
insulation value (0.05W/mK). High porosity of the silica aerogel is the important aspect of aerogel
pore network and its interconnectivity. These pore structures of silica aerogels leads to application
as filters, absorbing media for desiccation and waste containment[1]. Building through cooling and
heating requirements are major contributors to energy consumption worldwide. In order to prevent
current situations, building envelope is very important building components to provide thermal
comfort for the residents as well as reduce energy consumption to maintain indoor conditions [2].
Kim et al. reported recently the insulation performance of aerogel cement prepared by mixing
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Thanuja M Y, Karthigeyan
aerogel powder, methanol, and cement paste; thermal conductivity of aerogel cement with aerogel
mass fraction of 2.0 wt.% was found to be decreased by maximum 75% of aerogel free cement [3].
The most of tradition products are made of the polystyrene and composite materials laminated with
the organic and inorganic substances have been used in the building and manufacture fields
because of affordable prices to reduce amount of construction costs [4]. The insulation materials
are used by themselves in buildings, there is a negative behavior not to show their insulation
performance in case of absorbing the leakage water or vapors through the air flow for long time
being damaged by external impacts, or releasing toxic gases during a fire[5].
Light weight nanoporous silica aerogel were discovered in the early 1930. The preparation of silica
aerogel were described by Brinker and Scherer [6]. The precursors used for preparation of silica
aerogel are silica alkoxides such as TEOS (tetraethoxysilane) , TMOS ( tetramethoxysilane) etc.
Silica aerogel were dried under supercritical condition to remove the capillary force acting on the
wall of the each pore, which reduces the surface tension and helps for forming the gel without
cracking [7].
This work is interest to study silica aerogel incorporated in cement and white cement. The
stability/durability of aerogel particles in concrete is worth studying since the alkaline environment
during the hydration of cementitious materials may destroy silica aerogel. The results obtained
would be very helpful for the applications of aerogel materials in building sector [8]. In this paper
we report an experiment study on lightweight and thermal insulating of silica aerogel incorporated
in cement and white cement composites are discussed.
2. EXPERIMENTAL
Materials And Methods
Tetraethoxysilane(TEOS), ethanol , ammonium fluoride , ammonia were used for the synthesis of
silica aerogel. Ultra tech cement (Grasim) and white cement ( wall care kutti) were used for the
preparation of composites with silica aerogel.
Synthesis Procedure
Silica aerogel was prepared by using TEOS:H2O: C2H5OH :NH3:NH4 F . 0.5M of ammonium
fluoride was prepared. 10ml of Ethanol and 7ml of distilled water was pipette out to the breaker on
the magnetic stirrer which is stirring at 400rpm. 0.03ml of Ammonium and 0.3ml of ammonia
fluoride was added to the breaker after few minutes of stirring . 5ml of TEOS was added to the
mixture , stirred after 5minutes. After 5min of stirring a clear sol formed . These sol was
transferred to box where sol was formed gel. Gel was kept for one day to form a layer between the
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Study of Nanoporous Silica Aerogel Composite for Architectural Thermal Insulation Application
box and gel . after the layer was formed . Gel was kept for solvent exchange for one week . Silica
gel was dried under supercritical condition. During supercritical drying, the silica aerogel is kept in
the cylindrical vessel and the ethanol was added to the cylindrical vessel till the silica aerogel was
completely deeped in the ethanol . The cylinder is covered with the lid , clamped and tightens the
screws provided. The program was set in the controller in 4 steps , in the first step , the temperature
was set to above the critical temperature of ethanol 243°C and critical pressure 80bar . second step
was to kept the gel for soaking . third step was venting in two steps . venting step was done to
release the pressure and temperature without causing shrinkage and damage to silica aerogel ,
therefore venting step was done in two steps.
Preparation of cement and white cement composites:
Cement and white cement were taken. Loading of silica aerogel at different weight percent such as
5%, 8%,10% and 12%. The volume percent of silica aerogel for corresponding weight percentage
is 25ml, 30ml, 36ml and 45ml. Incorporation of silica aerogel with building material such as
cement and white cement was done by mechanical mixing. Mechanical mixing of different weight
% of silica aerogel with cement and white cement was done. After that addition of water to the
mixture and mixed well. The paste was put to the molds and removal of molds, gives the cement
and white cement composites. These composites were dried under ambient condition till it is
completely dried. Each one of the cement and white cement composite were kept for curing under
water for 3days. After curing, the composites were dried under ambient condition.
3. RESULTS AND DISCUSSION
Silica Aerogel
Brunauer-Emmett-Teller (BET)
b
a
3000
silica aerogel Adsorption dV/dD Pore Volume
0.008
Silica Aerogel isotherm
Pore Volume (cm³/g·Angstrom )
Quantity Adsorbed (cm³/g STP)
3500
2500
2000
1500
1000
500
0.007
0.006
0.005
0.004
0.003
0.002
0.001
0
0.000
0.0
0.2
0.4
0.6
Relative Pressure (P/Po)
0.8
1.0
0
200
400
600
800
1000
1200
1400
Pore Diameter (Angstrom)
Fig 1(a); silica aerogel isotherm, 1(b); silica aerogel dV/dD pore volume.
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Thanuja M Y, Karthigeyan
From fig 1(a) & 1(b) gives the BET surface area of silica aerogel and adsorption dV/dD pore
volume . Brunauer, Emmett and Teller (BET) is the common method used to describe specific
surface area, pore size distribution Silica aerogel having surface area of 462.0828 (m²/g) , Pore
Volume 1.030935 (cm³/g) & Pore Size 89.2424 ( Å) .
Silica Aerogel composites:
b
a
10 Wt%silica aerogel cement composite isotherm
10 Wt%silica aerogel white cement composite isotherm
0.0012
100
Pore Volume (cm³/g·Angstrom)
Quantity Adsorbed (cm³/g STP)
120
80
60
40
20
0
dV/dDPorevolumefor 10wt%Silicaaerogel cement composite
dV/dDPorevolumefor 10wt%Silicaaerogel whitecement composite
0.0010
0.0008
0.0006
0.0004
0.0002
0.0000
0.0
0.2
0.4
0.6
0.8
Relative Pressure (P/Po)
1.0
0
500
1000
1500
2000
2500
PoreDiameter (angstrom)
Fig 2: a) comparison graph for 10 wt % silica aerogel with cement and white cement
composite isotherm , b) comparison graph for 10 wt% silica aerogel with cement and cement
composite dV/dD pore volume.
Surface area of the cement is 2.1680 (m2/g). 10wt% of silica aerogel incorporated cement
composites having a surface area is 74.839 (m2/g). Pore volume of 10 wt% of silica aerogel
incorporated cement composite is 0.1436 (cm3/g) . Pore size of 10wt% of silica aerogel
incorporated cement composite is 76.75(Å). Surface area of the composites increases as the weight
percent of silica aerogel content increases.
Surface area of the white cement is 1.1789 m2/g. 10wt% of silica aerogel incorporated white
cement composite having a surface area is 9.2610 (m2/g) . Pore volume of 10wt% of silica aerogel
incorporated white cement composite is 0.0289 (cm3/g). Pore size of 10wt% of silica aerogel
incorporated white cement composite is 125.013(Å). Pore size of white cement composite is high
compare to pore size of cement composite.
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Study of Nanoporous Silica Aerogel Composite for Architectural Thermal Insulation Application
4. DENSITY VARIATION FOR COMPOSITES:
u n c u r e d c e m e n t c o m p o s ite
C u r e d c e m e n t c o m p o s ite
U n c u r e d w h ite c e m e n t c o m p o s ite
C u r e d w h ite c e m e n t c o m p o s ite
2 .6
2 .4
2 .2
Density g/cm
3
2 .0
1 .8
1 .6
1 .4
1 .2
1 .0
0 .8
0
2
4
6
8
10
12
% L o a d in g o f s ilic a a e r o g e l
Fig 3: density Vs % loading of silica aerogel for cement and white cement composite
Silica aerogel is characterized by low density and high porosity where the density is correlated to
the porosity. The above graph shows the density variation of cement composite with and without
curing. On comparing the cement composites with and without curing, cured cement composite is
having low density. Comparing the cement and white cement composite, white cement composite
shows less density. The density of the composites decreases with the increase in loading of silica
aerogels.
5. COMPRESSIVE STRENGTH VARIATION FOR COMPOSITES:
Compressive strength (MPa)
300
U n c u r e d c e m e n t c o m p o s ite
C u r e d c e m e n t c o m p o s ite
U n c u r e d w h ite c e m e n t c o m p o s ite
C u r e d w h ite c e m e n t c o m p o s ite
250
200
150
100
50
0
0
2
4
%
6
8
10
12
L o a d in g o f S ilic a A e r o g e l
Fig 4: Compressive strength Vs % loading of silica aerogel for cement and white cement
composite.
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Thanuja M Y, Karthigeyan
cement composites (with and without curing ) were prepared . The strength of the composites were
increased when the cement composite kept for 3days curing. Compressive strength of the
composites decreases as the % loading of silica aerogel increases. White cement composite with
and without curing were prepared . Compressive strength of the cured white cement composite
shows more strength than uncured composites.
6. THERMAL INSULATION TESTING
Thermal insulation test was done by placing the composites on heater which is connected to two
thermocouples one at bottom of the composite ( hot side) and other at top of the composite ( cold
side). Comparison study of heat transfer from hot side to the cold side of the composites. By
comparison uncured cement composites gives better insulation than cured cement composites.
Uncured white cement composites shows good thermal insulating properties than the uncured
cement composite.
7. CONCLUSION
Synthesis of Silica Aerogel was carried out by sol-gel process. Drying of silica aerogel was carried
by supercritical condition. Characterization of silica aerogel shows that silica aerogel have high
surface area, low thermal conductivity and porous material. Cement is building material when
silica aerogel incorporated with cement, it gives low thermal conductivity and also light weight
composites. Cement and white cement composites were prepared by varying the loading of silica
aerogel. Density of the composite decreases by increasing the loading of silica aerogel. Cured
composites shows the increases in compressive strength compare with uncured composites.
Thermal insulation testing results shows that uncured cement composites gives better insulation
than cured cement composites. Further study of incorporation of silica aerogel with building
material required to increase the strength of the composites and also increase the thermal insulation
properties of the composite.
REFERENCES
[1] Alain C. Pierre and Ge´rard M. Pajonk, Chemistry of Aerogels and Their Applications , 2002, Chem.
Rev., 102, 4243-4265
[2] Jyoti L. Gurav,1 In-Keun , Silica Aerogel: Synthesis and Applications, 2010, Journal of Nanomaterials,
[3] A. Soleimani Dorcheh, M.H. Abbasi, Silica aerogel; synthesis, properties and characterization, 2007,
journal of materials processing technology 1 9 9 ( 2 0 0 8 ) 10–26.
[4] Yu. K. Akimov, Fields of Application of Aerogels (Review), 2003, Instruments and Experimental
Techniques, Vol. 46, No. 3, 2003, pp. 287–299.
[5] Lawrence W. Hrubesh, Aerogel applications, 1998, Journal of Non-Crystalline Solids 225 1998. 335–
342.
[6] Ruben Baetens, Bjørn Petter Jelle , Aerogel insulation for building applications: A state-of-the-art
review, Arild Gustavsend ,2011, Energy and Buildings 43 (2011) 761–769.
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
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Study of Nanoporous Silica Aerogel Composite for Architectural Thermal Insulation Application
[7] Sughwan Kim, Jungki Seo , Chemical retreating for gel-typed aerogel and insulation performance of
cement containing aerogel, 2013, Construction and Building Materials 40 (2013) 501–505.
[8] M. Reim *, W. Ko¨rner, J. Manara , Silica aerogel granulate material for thermal insulation and
daylighting, 2005, Solar Energy 79 (2005) 131–139.
[9] A. Venkateswara Rao *, P.B. Wagh, Preparation and characterization of hydrophobic silica aerogels,
1998, Materials Chemistry and Physics 53 ( 1998) 13-18.
[10] Kelly E. Parmenter, Frederick Milstein, Mechanical properties of silica aerogels 1998, Journal of NonCrystalline Solids 223 1998. 179–189.
[11] Ai Du, Bin Zhou , Zhihua Zhang and Jun Shen, A Special Material or a New State of Matter: A Review
and Reconsideration of the Aerogel , 2013, Materials 2013, 6, 941-968.
[12] Tao Gao, Bjorn Petter Jelle, Arild Gustavsen, Stefan Jacobsen, Aerogel-incorporated concrete: An
experimental study, 2014, Construction and Building Materials 52 (2014) 130–136.
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Potential of India for Ethanol as a Transportation Fuel
Vivek Pandey1, Vatsal Garg2, Niraj Singh3, Deepak Bhasker4, Partha Pratim Dutta5
1, 2, 3,4
Department of Mechanical Engineering, Maharaja Agarsain Institute of technology Pilukhuva,
Ghaziabad, Uttar Pradesh
5
Department of Mechanical Engineering, Tezpur University, Tezpur, Assam
ABSTRACT
Ethanol being an oxygenate fuel proved to be a good substitute for petrol and diesel engine with
little or no modification into the engine make up. At present, ethanol is the most widely produced
biofuels in India. it is mainly produced using sugarcane as feedstock. For successful
implementation of the EBP (Ethanol Blending Programme) in the country, a steady supply of
sugarcane (or sugarcane juice) as feedstock is required. Sugarcane and molasses which are
suitable feedstock for ethanol production are not able to fulfill the government mandation of
ethanol blending in the future. On the other hand cellulosic biomasses which are available in
abundant amount in India have potential to replace 20% petroleum based fossil fuels by 2017.
The present paper discusses first and second generation ethanol fuel. Ethanol as an IC engine
fuel posses little or no problem with petrol engine but with diesel engine it poses some problem
which require further research. Presently India uses only 5% blending of ethanol. However, for
achieving higher ethanol blending programme which was established by government of India, a
continuous supply of this fuel is needed which can be fulfill by second generation ethanol due to
abundance of biomasses in India. This paper also focuses on some experimental studies which
were conducted in the past by using ethanol blend in diesel and petrol engine.
Keywords: Ethanol, Biofuels, Ethanol blending programme, Sugarcane, Molasses,
Biomass.
1. INTRODUCTION
According to worlds coal Institute, India is producing 2.4% of the world’s total annual energy.
Whereas it is consuming 3.7% of the world total energy consumption [1]. This is how India is the
fifth largest consumer of energy in the world, and is likely to surpass Japan and Russia to become
worlds third biggest energy consumer by 2030[2]. Biofuels are going to play an extremely
important role in meeting India’s energy needs. The country energy demand is expected to grow at
an annual rate of 4.8% over the next couple of decades. Biofuels are renewable liquid fuels coming
from biological raw materials and have been proved to be good substitutes for oil in transportation
sector. Biofuels such as ethanol is gaining momentum over the whole world as a solution to
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Potential of India for Ethanol as a Transportation Fuel
environmental problem, energy security, reducing imports, rural employment, and improving
agricultural economy and also to achieve prescribed emission norms [3].
2. ETHANOL POTENTIAL OF INDIA
First and second generation ethanol. India mainly uses first generation feedstocks such as
sugarcane molasses for ethanol production. The availability of surplus ethanol from molasses is
very limited. The other option for first generation ethanol is starchy biomass like grains and tubers.
However, in a country like India with the world’s second largest population to feed, and with more
than 238 million people living below the poverty line sparing food crops for ethanol production is
not an option[4]. Whereas Second generation ethanol which is made from cellulosic biomass such
as corn Stover, switch grass, crop residues. India produces 440 MT of crop residues annually; this
translates to about 130 MT of ethanol per annum. Cellulosic ethanol is in new stage in India. It is in
R&D stage only and few pilot projects are running on this. The following table presents the key
differences between first (conventional) and second (cellulosic) generation ethanol.
. Table. 1 Conventional and Cellulosic Ethanol – Comparison
Aspect
Conventional Ethanol
Cellulosic Ethanol
Feedstock’s are agriculture plants like
corn wheat, soybeans, sugarcane etc
Feedstocks are agricultural plant
wastes like corn stover, cereal
straws, and sugarcane bagasse,
plant wastes from industrial
processes like sawdust, paper pulp
as well as switchgrass.
Food vs Fuel
Ethanol production carries the risk
that food cropping will turn into more
lucrative fuel-cropping
Cellulosic ethanol
prevents the danger
Feedstock
Availability
The supply of raw material is scarce
The supply of raw material is
much higher than that for first
generation ethanol
High amounts of fertilizers and water
essential for ethanol production
The quantities of fertilizers and
waters required are not as high as
those for feedstocks for first
generation ethanol
Corn ethanol extraction from
feedstock is simple and economic.
Cellulosic ethanol extraction from
feedstock is complex and less
economic.
Choice
Feedstock
Fertilizer
Water Use
Production
Process
of
and
production
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Vivek Pandey, Vatsal Garg, Niraj Singh, Deepak Bhasker, Partha Pratim Dutta
The only disadvantage of cellulosic ethanol lies in the difficulty with which it is presently
extracted. India is still lacking in mature technologies for ethanol production from biomasses which
is by far the most abundant energy source.
Ethanol supply and demand in India. India is the fourth largest producer of ethanol in the world.
India uses sugar, cereals, sugar beet to molasses as a raw material ethanol production. The average
sugar cane productivity in India is about 70MT per hectare and ethanol produced from one MT of
sugar cane is 70 litres. According to Indian Sugar Mills Association (ISMA), annual sugarcane
production in 2011-12 is estimated to be around 380 million tones. In a recent report, the US
Department of Agriculture (USDA) has pegged India's ethanol production at 2,170 million litres in
2012, against 1,681 million litres last year. On the total sugarcane production in India, 60% is
utilized for sugar production by sugar mills. At present condition also, 25-30% of sugarcane
produced is processed for production of unrefined sugar [5]. In the year 2003, the Report of the
Committee on Development of Biofuels published by the Planning Commission of India gave
projections of demand and supply of ethanol for India for the end of each five-year plan (shown in
Table 2)[6].
Table 2: Projected Demand and Supply of Ethanol (million litres)
Year
2001–
02
2006–
07
2011–
12
2016–
17
Molasse Cane
s
Total
Ethanol Blending Petrol Demand
for
Industry Potable Balance Requirement
Transport Sector
1775
1775
600
Ethanol production
2300
2300
2300
0
1485
1485
1485
3785
3785
3785
Ethanol utilisation
711
844
1003
648
765
887
1028
527
2309
2054
1754
5%
448.03
10%
896.05
20%
1,792.10
5%
638.14
10%
1,276.27
20%
2,552.54
5%
814.30
10%
1,628.61
20%
3,257.22
5%
1,039.27
10%
2,078.54
20%
4,157.07
8,960.52
12,762.72
16,286.09
20,785.36
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Potential of India for Ethanol as a Transportation Fuel
This report shows the break-up of production and consumption of ethanol in terms of molasses and
cane.
Ethanol as a motor fuel - Advantages and Disadvantages. The total registered motor vehicles in
India in fiscal year 2005/06 numbered approximately 90 million [7]. Increased motorization and
tight emission norms has accelerated ethanol blending programme in India in last few years.
Presently bioethanol consumption is restricted to transportation sector only. The Indian biofuels
consumption market had total revenue of $277 million in 2010, representing an annual growth rate
(CAGR) of 18.6% for the period 2006-2010 [8]. By 2017, the government of India (GOI) mandates
replacing 20% of petroleum based motor fuel with biofuels.
The advantages of using ethanol as automobile fuel is that they are oxygenate containing 35%
oxygen and are renewable. They reduce hydrocarbon emissions such as CO and eliminate emission
of lead, benzene; butadiene etc. The calorific value of ethanol is lower than that of gasoline by
40%. It makes up a part by increased efficiency. Blends below 10% of ethanol do not present
problems. However, blends above 20% pose certain difficulties such as (i) higher aldehyde
emission(ii) corrosiveness, affecting metallic parts, but 10% ethanol blend no compatibility
problem have been found (iii)higher latent heat of vaporization causing start ability problem, but
blends upto 25% ethanol in gasoline poses no problem. (iv) higher evaporation losses due to higher
vapour pressure and(v) requiring large fuel tank due to lower calorific value. Table 3 presents
properties of ethanol as compared to conventional fuel [9].
Table 3: Energy value and properties of various fuels
Parameter
Petrol
Diesel
Ethanol
Energy content(MJ/Kg
43.65
45.15
29.73
Liquid density (Kg/I)
0.735
0.843-o.848
0.77843
Energy density (MJ/I)
32.1
38.16
23.32
Normal b.p.( 0 c)
37-205
140-360
79
Octane#
91-97
25
111
Cetane#
0-5
45-55
5
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Recent trends of ethanol in diesel and petrol engines. In diesel engines ethanol blend poses
some problem. A 15% ethanol blend reduce particulate emission, however the blend provides
certain technical problems. Ethanol reduces the flash point of blend to 13°C. it reduces the lubricity
of fuel and causes wear of piston rings and injector. Ethanol and diesel does not mix properly,
Effective emulsifier is required. The cetane no of ethanol is just 8 and so reduces the cetane no of
diesel on blending.
The greatest scale fleet trials is being conducted in the state of Karnataka in India, where the largest
ethanol-diesel fleet in the world comprises about 5,200 buses using O2-diesel(Enerdiesel), a diesel
containing 7.7% ethanol and 0.5% biomass based additives[10]. In the past it was reported that
ethanol diesel blend up to 20% can be used in constant speed engines without any hardware
modifications and leads to significant reductions in CO and NOx emission[11].
Engine performance, combustion and exhaust emission characteristics of a single cylinder four
stroke diesel engine using different blends of ethanol such as E0-neat diesel,E10, E20,E30,E40 and
E50 was tested. To satisfy homogeneity and prevent phase separation, 3% of ethyl acetate was
added to ethanol-diesel blend. This study shows that BTE is improved by 8% for 10% ethanol
addition and only 2% increases on further ethanol addition with added advantages of reduced
specific fuel consumption. Ignition retards and combustion duration shorten, which results in rapid
combustion and NOx emission is reduced by 8% with 10% of ethanol blend [12]. Experiment on
hexanol as an additive to prevent phase separation was also observed. Five kinds of fuel were
prepared: diesel (D0) as base line fuel, 20% ethanol blending with 105 hexanol and 705
diesel(denoted as D20E) similarly D25E, D35E and D45E. Among these blends D20E shows
higher BTE and D35E shows better smoke reduction, D25E shows maximum heat release rate.
Finally, all the blends slightly increase the NOx emission beyond 75% load than that of diesel [13].
Ethanol is a high performance biomass fuel. It is most suited alcohol for SI engine. The most
attractive property of ethanol is its ability to be produced from renewable energy sources, its high
octane no, and its high laminar flame speed [14].
In gasoline engine different blends of ethanol has been tested. A 4-stroke, four cylinder, varying
RPM, petrol(MPFI) engine was tested on blends containing 5%, 10%, 15%, 20% ethanol and it was
found that exhaust gas emission such as HC,O2, CO,CO2, decreases and BTE increases. Result
shows that 10% ethanol blend is most attractive and we can utilize it for further use in SI engine
with little constraint on material used to sustain little increase in pressure [15]. It was observed that
ethanol blends (up to 30% by volume), when used as a fuel in spark ignition engines, reduce NOx
emissions [16]. Other experiment has reported that emission of NOx is same for E10 and gasoline
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Potential of India for Ethanol as a Transportation Fuel
[17]. As for as emission is concerned, ethanol blending with gasoline decreases many toxics, such
as aldehydes in presence of ethanol which acts as a ozone precursor and increases the smogformation potential [18].
Catalytic converters have been used to reduce pollutants in SI engine reduction of pollutants
depends upon mass of catalyst, amount of air injected in catalytic chamber [19]. Engine
modification with copper coatings on piston crown and inner side of cylinder head improves engine
performance as copper is a good conductor of heat and combustion is improved with copper
coating. In a experiment of 2-stroke, single cylinder SI engine, with alcohol blended gasoline(80%
gasoline, 10% methanol, 10% ethanol by volume) having copper coated combustion chamber
provided with catalytic converter with sponge iron as catalyst. The result shows that thermal
efficiency increased by 9%, 8% and exhaust gas temperature decreased by 19%, 5% with gasoline
operation and alcohol blended gasoline operation respectively[20].
3. CONCLUSION
In India the ethanol industry is mature, but with efficiency improvements, the use of alternate crops
and the deployment of new technologies like enzymatic fermentation of cellulosic material, it can
easily supply the ethanol requirements for 5 per cent or even 10 per cent ethanol blending. It is
technically feasible to design and run automobiles on 100% ethanol; but for the reason of
availability and compatibility with vehicles presently in use, blending of ethanol with motor spirit
needs to make a very modest beginning. Second Generation Biofuels Can Provide a Solution to
India’s Transport Fuel Woes, But Only If Government and Industry Take Proactive Measures and
Make Significant Investments. Being oxygenate fuel ethanol offers less emission in IC engines. In
diesel engine, ethanol does not mix with diesel, hence effective emulsifiers are required and to
prevent phase separation certain additives are required. Catalytic converters are used in petrol
engine to reduce pollutants. Ethanol has less calorific value which is compensated by improved
thermal efficiency.
REFERENCES
[1] The Brookings Foreign Policy Studies Energy Security Series India, November 2006.
www.brookings.edu/~/media/research/files/reports/.../india/2006india.pdf.
[2] Report of the committee on the development of biofuels. Planing commission government of India New
Delhi. April 16, 2003.
[3] National Sample Survey Reports, National Sample Survey Organization. Ministry of Statistics and
Program
Implementation,
Government
of
India.2007
http://www.mospi.gov.in/mospi_nsso_rept_pubn.htm.
[4] Sharma Y.C, B. Singh and S.N. Upadhyay. 2008. Advancements in development and characterization of
biodiesel: A review. Fuel. 87: 2355-2373.
Emerging Energy Technology perspectives-A Sustainable Approach - ISBN: 978-93-83083-73-2
249
Vivek Pandey, Vatsal Garg, Niraj Singh, Deepak Bhasker, Partha Pratim Dutta
[5] Ray S, Miglai S, Goldar A. ICRIER Policy Series, ethanol blending policy in india: demand and supply
issues. December 2011.
[6] Mustard
A,
Biofuels
Annual.
India,
2012.
gain.fas.usda.gov/.../Biofuels%20
Annual_New%20Delhi_India_6-20-20.
[7] Biofuel
Consumption
In
India.Market
Research
Report
Portal.
nebulodi.com/ko/Biofuel_Consumption_in_India.htm.
[8] Srivastava A, Srivastava S , Nigam A.C. Alternative Fuel for Transportation. International Journal of
Environmental Sciences 2010; 1(2): 191-197.
[9] ENVIS (Environmental Information System), MoEF (Ministry of Environment and Forests),
Government of India, Web site, “Pollution control technology.” http://www.terienvis.nic.in, accessed
2007.
[10] Agarwal, Avinash Kumar. 2007. Biofuels (alcohols and biodiesel) applications as fuels for internal
combustion engines, Progress in Energy and Combustion Science, 33, pp.233-71.
[11] Gnanamoorthi V, Devaradjane G. Effect of Diesel-Ethanol Blends on Performance, Combustion and
Exhaust Emission of a Diesel Engine. International Journal of Current Engineering and Technology
2013; 3(1): 36-42.
[12] Sathiyagnanam A.P, Saravanan C.G, Gopalakrishnan M. Hexanol-Ethanol Diesel Blends on DI-Diesel
Engine to Study the Combustion and Emission. Proceedings of the World Congress on Engineering
2010; 2: ISBN: 978-988-18210-7-2.
[13] Bayraktar, H., 2005, “Experimental and Theoretical Investigation of Using Gasoline-Ethanol Blends in
Spark-Ignition Engines,” Renewable Energy, 30, pp. 1733-1747.
[14] Kumar J, Ansari N.A, Verma V, Kumar S. Exhaust Gas Analysis and Parametric Study of Ethanol
Blended Gasoline Fuel in Spark Ignition Engine. American Journal of Engineering Research (AJER)
2013; 2(7): 191-201.
[15] Baghdadi-Al, M., 2008, “Measurement and Prediction Study of the Effect of Ethanol Blending on the
Performance and Pollutants Emission of a Four-Stroke Spark Ignition Engine,” IMechE, 222(D), pp.
859-873.
[16] Karman, D., 2003, “Ethanol Fuelled Motor Vehicle Emissions: A Literature Review,” Health Canada,
Carleton University.
[17] Sahu R. Overview- Impacts of Mid-Level Ethanol On- Road and non road engines and equipment, 2009.
nmma.org/.../Exhibit%20A-1%20ALLSAFE%20e-15%20Waiver%20Co.
[18] Murali Krishna M.V.S, Kishor K. Control of pollutants from copper coated spark ignition engine with
methanol blended gasoline,ῆ Indian Journal of Environmental Projection 2005; 25 (8):732-738.
[19] Murali Krishna M.V.S, Kishor K, Prasad P.R.K, Swathy G.V.V. Parametric studies of pollutants from
copper coated spark ignition engine with catalytic converter with gasoline blended methanolῆ, Journal
of Current Sciences 2006; 9 (2):529-534.
[20] Kishor K, Murali Krishna M.V.S, Murthy P.V.K. Comparative Studies on PerformanceParameters and
Exhaust Emissions from Four Stroke Copper Coated Spark Ignition Engine with Alcohol Blended
Gasoline with Catalytic Converter. International Journal of Innovative Research in Science, Engineering
and Technology 2013;2(12):7343-7352.
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Antenna Design and Optimization for RFID tag using
Negative µ and ε Material
Shankar Bhattacharjee1, Rajesh Saha1, Santanu Maity2*
1
Computer Science and Engineering, National Institute of Technology, Arunachal Pradesh, India
Electronics and Communication Engineering, National Institute of Technology, Arunachal Pradesh, India
2
ABSTRACT
RFID is one of the implementations under auto- identification techniques. In RFID there are
mainly three parts. The three parts are tag, reader and the host. The tag consists of an
Application Specific Integrated Circuit (ASIC) chip on it. The reader sends an electromagnetic
signal to the passive tag and on receiving the signal the tag activates its chip and sends the
modulated data to the reader. After that the reader demodulates the data and receives it.
Generally we make use of rectangular patch antenna in RFID devices. Most important
parameters of an RFID antenna are radiation, directivity, bandwidth, return loss etc. So for
improving the above mentioned characteristics we have incorporated a meta-material structure
(split ring resonator) within the patch. The permittivity and permeability of meta-material
structures depends on the shape rather than the composition. Thus we can exploit different
shapes of this material to obtain much efficient results. In this way after simulation we obtained
higher bandwidth, gain and increased number of radiating bands than the previous results. This
result has paved the way to develop resourceful antennas which can revolutionize the field of
RFID.
Keywords: Radio frequency identification, split ring resonator, application specific integrated
Circuit, ultra high frequency.
1. INTRODUCTION
The use of Radio Frequency Identification (RFID) has grown exponentially in many fields like
animal tracking, vehicle tracking, manufacturing company, business etc. The RFID consist of a
reader, a several tags around the reader and the host [1]. The tag consists of a chip on it. The tag
may be passive or it may be active. In active tag, it consists of an internal battery which activates
the chip of the tag. In passive tag the chip is activated by the electromagnetic wave which is sent by
the reader to the tag to collect the data. A transmit and receive antenna is connected to the reader
and the tag also has a single antenna for transmitting and receiving. In passive tag the reader sends
a electromagnetic wave to the tag with the help of an antenna and on receiving the wave the tag
activates its chip. After that tag modulates the signal and sent the data to the reader. On receiving
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Shankar Bhattacharjee, Rajesh Saha, Santanu Maity
this signal the readers demodulates the signal and receive it
i [2]. The Amplitude Shift Keying
(ASK) modulation technique is used by the tag. Hence by changing the input impedance of the tag,
it is able to send two backscattered signal. One backscattered signal corresponds to binary 0 and
another one corresponds to binary 1. By using timing information between the the two
backscattered signal, the tag is able to transmit the data to the reader. In the below figure we give
an overview of a passive RFID system [3].
Figure1: Overview of a passive RFID system
For transmit
mit and receive the signal in RFID technology antenna plays a crucial role. So we have to
design an effective and efficient antenna. The main parameter of antenna on which its performance
depends are return loss, beamwidth, bandwidth, axial ratio, gain and size [4]. In this paper first of
all we design a general rectangular patch antenna and we simulate the design and got some result.
The metamaterial such as Split Ring Resonator (SRR) has the property of negative permeability
and permitivity. If both the permeability
ermeability and permittivity are negative then the composite posses an
negative index of refraction for isotropic medium [5, 6]. The metamaterial based antenna is used to
improve the read range and reduce the size of the tag and also increase the bandwidth,
bandwidth gain of the
antenna [7]. Hence in the consecuitive step we design a U shape SRR on the rectangular antenna to
enhance the gain and bandwidth of the antenna.
General consideration in RFID for tag antennas
The RFID system works on Low Frequency (LF), High Frequency (HF), Ultra High Frequency
(UHF) and microwave frequency band. But LF and HF has low data rate and reading range also not
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Antenna Design and Optimization for RFID tag using Negative µ and ε Material
so long. UHF has high data transmission rate and reading range is also large [8].The reader is
connected to an antenna with fixed gain and the tag also has an antenna with a fixed gain. There are
vast numbers of factors on which performance of tag depend .But we concentrate on the following
two performances [9, 10]:
• Tag sensitivity
• Tag range
Tag Sensitivity- Tag sensitivity is related with the forward link that when reader transmits its signal
to the tag and tag sensitivity is the minimum power /field required by the reader to read the tag at
the location of tag. It is a function of tag sensitivity threshold power, tag antenna gain and match
between tag antenna and power collecting state of the chip. The tag sensitivity (Ptag) is given by
Ptag= Pth G p z
(1)
Where Pth is threshold power to activate the chip, G is the gain of tag antenna, p polarization
efficiency, z is matching between chip and tag antenna.
Tag Range-Tag range is defined as the maximum distance at which tag can read. Is is a function of
Equivalent Isotropic Radiated Power (EIRP) transmitted by the reader and tag power. The tag
range (Rtag) is given as belowRtag= (lamda/4π)√¥mV"/√"&xÎ……
(2)
Where Ptag is the tag power.
Thus in RFID system it is very desirable to achieve largest possible read range.
2. ANTENNA MODELING AND SIMULATION
Initially we designed a rectangular patch antenna having substrate Roger RT/Duroid5880(tm) with
dielectric constant ÏY =2.2.The patch and the ground plane are separated by dielectric material or
substrate. The patch may be circular, square or rectangular. But we designed the rectangular patch
on the substrate and simulation was carried out on HFSS (High Frequency Structure Simulator)
software. The patch we designed having length (L) = 12.45mm, width (W) =16mm, height (H)
=0.05mm. The insert feed method is used to enhance the bandwidth and gain of the antenna. The
various parameters like return loss, smith chart and gain are given in the following figures.
In the next step, we make some improvement by introducing a metamaterial on the patch of U-SRR
shape. The dimension of the metamaterial is of thickness of the ring= 2.23mm, size of the
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Shankar Bhattacharjee, Rajesh Saha, Santanu Maity
structure= 8.46mm×4mm, width of the ring = 4mm, ring gap= 2.46mm.Again we doing the same
simulation and got some effective result. The bandwidth and gain of new structure increases
inc
by
manifold. The smith chart also good impedance matching property.
Figure 2: Model of rectangular patch antenna
Figure3:S11 parameter of rectangular patch antenna
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Antenna Design and Optimization
ptimization for RFID tag using Negative µ and ε Material
Figure4: Gain of rectangular patch antenna
Figure5: Smith Chart of rectangular patch antenna
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Shankar Bhattacharjee, Rajesh Saha, Santanu Maity
Figure 6: Model of rectangular patch antenna with metamaterial
Figure7: S11 parameter of rectangular patch antenna with metamaterial
Figure8: Smith Chart of rectangular patch antenna with metamaterial
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Antenna Design and Optimization for RFID tag using Negative µ and ε Material
Figure9: Gain of rectangular patch antenna with metamaterial
3. RESULT AND DISCUSSION
Metamaterial structure is so much effective for getting better performance. The return loss (S11) of
the normal patch antenna at resonance frequency is -26.9782dB (as shown in figure 3) and return
loss with metamaterial U-SRR
SRR structure at resonance frequency -22.5045dB (as shown in figure 7).
The gain of the metamaterial structure (as shown in figure9) increases and bandwidth also
increases. The smith chart as given in figure 8 also shows some good result. Hence by using the
metematerial structure (shown in figure 6) we can enhance the gain and bandwidth by
compensating return loss.
4. CONCLUSION
In this paper first of all we discussed about introduction of RFID technology
technolo and after that we also
discussed about general consideration for designing RFID tag antennas. Normally patch antenna is
used as a tag antenna in RFID. Hence initially we designed a normal rectangular patch antenna. But
we can enhance the gain and bandwidth
dth of the RFID system if we design some metamaterial
structure in the patch. So in the consecutive step we designed a UU SRR shape and simulate the
design. We got some effective result and this type of antenna can be used for tag.
REFERENCES
[1] Daniel W. Engels,
gels, Tom A. Scharfeld, Sanjay E. Sarma,”Review of RFID Technologies”, Cambridge,
MA USA 02139.
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Shankar Bhattacharjee, Rajesh Saha, Santanu Maity
[2] Elisabeth ILIE-ZUDOR, Zsolt KEMENY, Peter EGRI, Laszlo MONOSTORI, ”The RFID technology
and its current Application”.
[3] Benjamin D. Braaten , Robert P. Scheeler ,“Design of passive UHF RFID Tag ntennas Using
Metamaterial – Based Structures and Techniques”, North Dakota State University, University of
Colorado-Boulder, United States.
[4] Pravel V. Nikitin , Senior Member IEEE , & K.V. S.Rao , Senior Member IEEE.”Antennas &
propagation in UHF RFID system “.
[5] Curty J.P., Declerdq M., Dehollain C. and Joehl N.,(2007) .”Design and Optimization of passive UHF
RFID System”, Springer, ISBN: 0-387-3527-0, New Jersey.
[6] Bimal Garg, Rahul Dev Verma, Ankit Smaditya,”Design of Rectangular Microstrip Patch Antenna
Incorporated with innovative Metamaterial Structure for Dual band Operation & Amelioration in Patch
Antenna Parameter with(-) µ and Ï” Department of Electronics Engineering, Madhav Institute of
Technology and Science , Guwalior, India.
[7] Lee, C.-J.; LeOng, K.M. K. H. & Itoh, T. “Design of resonant small antenna using composite right/left
handed transmission line”, IEEE Antennas and Propagation Society International Symposium , July,
2005,pp.218-221.
[8] Keskilammi M., Sydaheimo L. and Kivikoshi M. (2003). ”Radio frequency technology for automated
manufacturing & logistics control. Part1: Passive RFID system and the effect of antenna parameter on
operational distance”,The International Journal of Advanced Manufacturing Technology, vol.21, No.1011,pp.769-774.
[9] K. Ramakrishnan and D. Deavours, “Performance benchmarks for passive UHF RFID tags” Proceedings
of the 13th GI/ITG Conference on Measurement , Modeling, and Evaluation of computer and
Communication Systems, pp. 137-154,2006.
[10] Pavel Nikitin, KVK Rao , Sander Lum, “UHF RFID TAG CHARACTERIZATION: Overview and State
of the art”, Intermee Technologies Corporation, 6001 36th Ave W, Everett, WA 98203.
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Analysis of CDM Projects: An Indian Anecdote
Namita Rajput1, Vipin Aggarwal2, Ritika Ahuja3
1,2,3
Sri Aurobindo College (M)
ABSTRACT
The Clean Development Mechanism (CDM) is an element in the Kyoto Protocol that generates
credits – Certified Emission Reductions (CERs) – from emission abatement projects in
developing countries. The Clean Development Mechanism of the Kyoto Protocol allows
developing countries to profit from climate friendly projects, and India is second only to China
in using the mechanism to help reduce its carbon emissions. But, unlike China, India does not
have a national policy. India is one of the world's largest hosts of such clean development
projects, around one-quarter of the global total – had been registered with India's Designated
National Authority for the Clean Development Mechanism .As on 31 October 2013 total Global
CDM are 7366 and out of this 1444 projects are registered in India . The consequences of
India's liberal approach to the CDM for sustainable development remain unclear. The main
objective of this paper is to highlight limitations and issues of CDMs in India. In this paper five
CDM projects are analyzed. Our analysis reveals that because of the unclear policy of CDM,
there are severe ecological effects like displacement of people, rise in infertility of land, creation
of ash pond land degradation, effects on local water bodies, contamination of water and crops
etc. Criticisms are mainly focused on high transaction costs and lack of scalability; additional
challenges and lack of net mitigation impact; preventing more ambitious targets and changes in
emissions paths in developed and developing countries alike; excessive rents and perverse
incentives; unbalanced regional distribution; low local sustainable development benefits;
corruption and lack of transparency; and lack of technology transfer. Some important steps have
to be taken to control the unclean practices of Clean Development Projects so that there is no
question on them as to how clean these projects are.
Keywords: CDM, Carbon Credits, sustainability, environmental degradation.
1. SECTION 1: INTRODUCTION
The Clean Development Mechanism (CDM) is the world's biggest carbon offsets market. In theory,
the CDM allows industrialized countries to support projects that decrease emissions in developing
countries and then use the resulting emissions reduction credits towards their own reduction targets
under the Kyoto Protocol. Industrialized countries supported the establishment of the CDM
because it would provide them with flexibility in how they can meet their Kyoto targets,
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Namita Rajput, Vipin Aggarwal, Ritika Ahuja
particularly if domestic reductions turn out to be more costly than expected. Developing countries
supported the CDM because they would receive funds for "sustainable development." Kyoto
Protocol which came into effect on 2005 aimed to improve overall environment by reducing the
Green House Gases, which are constantly increasing these days leading climate change or Global
Warming.
Projects under Kyoto Protocol can be undertaken in three forms:
I.
Clean Development Mechanism (C.D.M)
II.
Joint Emission
III.
Emissions Trading
CDM mechanism under Kyoto Protocol aimed to bring clean and environment friendly technology
to developing country and also to help developed country to achieve their emission reduction-cost
efficiently. Nowadays there are lots of coal power plants which are being registered under Clean
Development Mechanism. Coal power plants generate 40% electricity worldwide and are
responsible for over 8 Giga tons of Co2 emission which is expected to grow 18 Giga tones by
2030. Efficiency of coal power plant ranges from 33%-43% depending on technology being used.
There are 3 types of technology being used in coal boiler namely- sub critical unit, super critical
unit and ultra super critical units. Government has made it compulsory to use super critical
technology though all power projects are still not using it.As mentioned earlier there are various
coal projects which are either registered or have applied for getting them registered under CDM.
But in reality all power projects including those that are registered under CDM are actually not
leading to any addition or they are causing ill effects in environment as well as human life in their
surrounding area.
They manipulate in terms of:
• Financing: Projects have several pre decided sources of financing because of which they need
not depend on CDM support.
• High estimated costs: Those projects that need CDM support show highly unrealistic estimates.
• Alternatives aren’t assessed properly: Various projects do not assess realistic and reliable
alternative to make coal a successful, environment friendly option.
Another shortcoming that is seen is Emission Reductions are calculated by subtracting emissions
from Baseline. For coal baseline is set on basis of emission of less efficient plant. So lower the
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Analysis of CDM Projects: An Indian Anecdote
assumed efficiency more credits a project will generate leading to artificial CER which aren’t
based on actual emission reductions.
The main objective of this paper is to analyze five Indian CDM Projects. To achieve the objectives
the paper it is divided into following sections, Section I, i.e. the present section gives the insights of
Kyoto protocol, and details of CDM. Section II will give the analysis of CDMs in India and its
environmental impacts followed by references
2. SECTION II: ANALYSIS OF INDIAN CDM PROJECTS
The following section gives the details of CDMs operational in India.
1)
SASAN ULTRA MEGA POWER PLANT (UMPP):
It is a huge thermal power project undertaken by Reliance. It aimed to provide 3960 MW to seven
states at the cost of 23000crore. Initially it was started as Special Purpose Company owned by
Power Finance Corporation which it through Bid system transferred it to Reliance Power. Various
banks like S.B.I, Bank of China, China Development Bank, and Export-Import Bank of China,
Export-Import Bank of United States, Standard Chartered Bank came forward in this project.
Project aimed to increase overall efficiency by consuming 1.5 million tones less of coal per year
compared to other project of same size thereby leading to decrease in reduction of GHG emission
by 14%.Sasan UMPP which was based on supercritical coal technology which is considered best
technology for mining operations was considered to be the one of the best greenest coal based
power plant in India due to which it got CDM status (ref: 3690)thereby allowing Reliance to earn
carbon credits. But there are questions being raised on its impact on environment. People living
there were given false promises to leave their homes. Many people have died while working at the
plant. Even the Ex-im Bank which is official export credit agency of United States government
rejected to finance this project on grounds of its carbon policy. But due to political pressure they
passed it by making a compromise in form of Memorandum of Understanding to generate 250MW
of renewable energy which is very less in terms of 3960MW power that plant will generate. Even
the Tata Power Company also filled petition against Reliance for its illegal use of surplus coal from
mines which was rejected on 14 April 2009. A nearby village named Harrahaawa village where
partial displacement has started, Reliance power ltd wants to build ash pond which will lead to land
becoming infertile as well as toxic.
2) NALLAKONDA – WIND FARM PROJECT , INDIA:
Wind power is a great source of renewable energy. Nallankonda Wind farm in Andhra Pradesh
generates electricity using wind. Project aims at exporting 50.4 MW of renewable electricity
generated using wind electric generators to southern region grid. But it is having negative effect on
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environment in form of deforestation, heavy land degradation, biodiversity loss. Local water bodies
are also being affected. It has applied for CDM status which is in consideration these days but
actually has lots of flaws and also lack parameters that are crucial for registration of CDM projects.
3) ADANI’S MUNDRA – ULTRA MEGA POWER PROJECT, INDIA:
It was registered with UNFCC’s CDM project (ref: 2716) named as “Grid connected energy
efficient power generation” having approx 606.306.It involves Adani’s Power Ltd as well as
France’s EDF Trading Ltd. It claims to reduce 1839516 metric tons of Co2 equivalent per year. But
report commissioned by committee of Indian Ministry Of Environment and Forest says that project
is actually violating the environment, harmfully affects local environment, affects fish
communities. It also leads to emission of fly ash which refers to ash produced during combustion
of coal. It includes substantial amount of silicon dioxide and calcium oxide which not only affects
environment but also has negative impact on health of people of the area, contaminates fish, field
as well as crops which makes them unfit for consumption. So it can be seen that Adani Mundra
Project is violating the mandates of CDM.
4) TIMARPUR-OKHLA, WASTE INCINERATION PROJECT, INDIA:
Project named “ The Timarpur –Okla. waste management company pvt ltd. Integrated waste to
energy project at Delhi” registered under UNFCC’s CDM project (ref#: 1254) illustrates how local
cycling economy is in danger by CDM’s incinerator projects. Project aims at generating power out
of waste which can be considered as a renewable energy source but has various shortcomings like:
•
•
•
It doesn’t reduce GHG. It is actually burning of waste to create energy which in turn leads to
GHG.
It is against sustainable development because burning of waste produces toxic chemicals
leading to pollution.
Dhaka Declaration of Waste Management adopted by South Asian Association for Regional
Cooperation (SAARC) also states that a country cannot opt for any burning or any unproven
technologies. It goes against that declaration.
5) RAMPUR –HYDRO POWER PROJECT INDIA :
Hydroelectric power project by SJVNL in Himachal Pradesh is registered under UNFCC’s CDM
project (ref: 4568) is a large scale World Bank hydro power project in Rampur. It is expected to
generate about 14 million carbon credits at estimated market value of $100 million USD. But its
addition to the environment is questionable. Various problems like dust, drying up of ground water,
negative effects on local agriculture, landslides can be seen.
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Analysis of CDM Projects: An Indian Anecdote
The table 1 gives the synoptic view of five CDM projects and its possible impact on the
environment.
TABLE 1: ANALYSIS OF INDIAN CDM PROJECTS
NAME
OF THE
PROJECT
STATES
STATUS
PARTIES
INVOLVED
Sasan
UMPP
Madhya
Pradesh
Registered
Ref#: 3690
Nallakond
a-wind
farm
project ,
India:
Andhra
Pradesh
In
consideratio
n
SBI, BANK OF
CHINA,
CHINA
DEVELOPMENT
BANK, EXPORTIMPORT
BANK
OF
CHINA,
EXPORT-IMPORT
BANK OF U.S,
STANDARD
CHARTERED
BANK
INDIA
Adani’s
Mundra–
ultra Mega
PowerProj
ect, India:
Gujarat
Registered
Ref#: 2716
Timarpurokhla,
waste
incineratio
n project,
India:
DELHI
Registered
Re#: 1254
AMOUNT
OF
REDUCTIO
N
2245875
metric tone
Co2
equivalent p
a.
ECOLOGICAL
IMPACTS
1)People were dispersed
from their homes.
2)lost their jobs
3)Creation of ash pond.
4)Over
dumping,
infertile land
5)scheduled tribe of M.P
Baiga tribe were ignored
100135
metric tone
Co2
equivalent
per annum
1)Affects local water
bodies.
2)Land degration.
Adani power Ltd.
And EDF Trading
Ltd
1839516
metric tone
Co2
equivalent
per annum
1)Excessive emission of
fly ash.
2)Contamination
of
water and crops
3)Violation of mandates
of CDM
M/S
Timarpur
Okhla
Waste
Management
Company
Private
Ltd.
262791
metric
ton
Co2
equivalent
per annum
1)Creation of pollution
by burning of waste.
2)Violation
of
international treaties like
Dhaka Declaration on
Waste Management by
SAARC.
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Namita Rajput, Vipin Aggarwal, Ritika Ahuja
Rampur –
Hydro
Power
Project
India :
3.
•
•
•
•
•
•
•
•
•
Himacha
l Pradesh
Registered
Re#: 4568
M/S
Satluj
Jal
Vidyut
Nigam
Limited (SJVNL),
International Bank
For Reconstruction
&
Development,
Swedish
Energy
Agency
1407658
metric
ton
Co2
equivalent
per annum
1)Landslides
2)Drying up of ground
water.
SECTION 111 REFERENCES
http://carbonmarketwatch.org/campaigns-issues/nallakonda-wind-farm-project-india/
http://carbonmarketwatch.org/campaigns-issues/rampur-hydro-power-project-india/
http://carbonmarketwatch.org/campaigns-issues/sasan-coal-power-project-india/
http://carbonmarketwatch.org/campaigns-issues/timarpur-okhla-waste-incineration-projectindia/
http://carbonmarketwatch.org/campaigns-issues/timarpur-okhla-waste-incineration-projectindia/
http://carbonmarketwatch.org/category/project-campaigns/
http://carbonmarketwatch.org/mundra-ultra-mega-power-project-india/
http://carbonmarketwatch.org/press-release-edf-trading-backs-away-from-adanis-carbonoffsetting-coal-project/
http://carbonmarketwatch.org/category/project-campaigns/
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Modeling and Simulation of Solar Cell Depending on
Temperature and Light Intensity
Shivam Dubey, Lipi Sarkar, Rishav Roushan, Santanu Maity
Electronics and Communication Engineering, National Institute
of Technology, Arunachal Pradesh, India
ABSTRACT
Capture the solar energy and convert it to the useable form is the challenge of energy
society.Solar cell is one of the relevant solutions for conversion of solar energy. But due to
different loss factor and burdening of environment at different place the efficiency of solar cell
is very much less. And on the other hand silicon is the promising and well known material for
getting low cost and better performance solar cell. Also further study is going on for making
more efficient solar cell. In this paper the modeling of solar cell using Matlab and QUCS
software has done and environmental effect like temperature and light intensity has been
discussed.
Keywords: solar cell; Solar panel ; temperature effect ; series resistance; shunt resistance;
efficiency of solar cell
1. INTRODUCTION
Day-by-day the energy demand is increasing and thus the need for a renewable source that will not
harm the environment are of prime importance. Yet majority of the energy requirements is satisfied
by fossil fuels but by the use of photovoltaic systems could help in supplying the energy demands.
Solar energy has the greatest potential of all the sources of renewable energy and if only a small
amount of this form of energy could be used, it will be of greater importance.
About 3.8x1024 joule of solar radiation is absorbed by earth and atmosphere per year. The energy
radiated by the sun on a bright sunny day is 4 to 7 wt/m2 [1]. But it is seen that under test condition
solar cell of 20\% efficiency with a 100 cm2 surface area would produce 20 Wt [2]. Commercial
solar cells range from 10% to about 20% [3].
The efficiency limit of solar cell which is related different loss factor describe by William Shockley
and Hans J. Queisser which is well known as Shockley-Queisser limit [4]. Different methods have
been introduced to overcome the Shockley-Queisser limit, such as adding impurities to high bandgap semiconductors [5] or by stacking several PN junctions with decreasing band-gaps, creating a
multi-junction Solar Cell [3]. In this paper the main parameter are temperature and light intensity.
From the two parameters solar cell performance is described.
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Shivam Dubey, Lipi Sarkar, Rishav Roushan, Santanu Maity
2. MODELING AND SIMULATION:
In solar cell main parameters are effect of recombination, series resistance, shunt resistance, and
different surface parameters those are responsible for reduction of solar sell efficiency. The
simplest model of solar cell is shown in fig. 1. In this paper first mathematical modeling is being
described and it is solved by Matlab [6]. First Cell temperature is calculated from eq. 1. Reverse
saturated current is calculated from eq. 2 which is related to cell temperature.
Fig. 1. Circuit representation of solar cell
Where A= Ideality factor ,q= Charge of 1 electron [Coulomb] ,k=Boltzmann constant [J/K] ,Eg=
Band gap energy [eV] ,Io= Reverse saturation current at Tr [A] ,Isc= Short circuit current
generated at Tr [A], ki= Temperature coefficient of short circuit current [A/K] ,ns= Number of cells
connected in series ,np= Number of cells connected in parallel ,Rs= Internal series resistance of a
cell [Ohm] ,Rp= Internal parallel resistance of a cell [Ohm] ,Tr=Reference temperature [K]
,NOCT=nominal operating cell temperature, G=Insolation (kW/m2) ,Ta= ambient temperature(oK).
From the flowchart in fig. 2 first put the value v=0 to calculate short circuit current. After that from
eq 3. And eq 4.
Total current and power is calculated. The total current must be not equals to photo generating
current. Then the process is finished. If the total current is equals to photo generating current then
go for the 2nd iteration. The model also created by using QUCS software and effect of temperature
and light intensity is analyzed (shown in Fig. 3).
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Modeling and Simulation of Solar Cell Depending on Temperature and Light Intensity
Fig. 2. Flowchart of solar panel simulation
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Shivam Dubey, Lipi Sarkar, Rishav Roushan, Santanu Maity
Fig. 3. Schematic diagram of solar cell using QUCS
3. RESULT AND DISCUSSIONS
From the Matlab modeling the temperature parameter is varied with respect to voltage and it is
seen that (fig. 4) that temperature increases and the open circuited voltage decreases. As the voltage
of solar cell decreases the power also decreases which is shown in fig.5.
Fig. 4. Voltage Vs Current using Matlab
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Modeling and Simulation of Solar Cell Depending on Temperature and Light Intensity
Fig. 5. Voltage Vs power using Matlab
From the model using QUCS software temperature and light intensity has been analyzed. By
simulating the solar model the perfect solar voltage and current result is optimized (shown in fig. 6)
It is seen in fig. 7 that when the voltage is high (or open circuit voltage) at that time current is
minimum (or zero) and when current (short ckt. current) is maximum the voltage is minimum
Which is ideal for solar cell.
Fig. 6. Voltage Vs Current using QUCS
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Shivam Dubey, Lipi Sarkar, Rishav Roushan, Santanu Maity
Fig. 7. Changing of cell current and cell voltage
And by changing the environment temperature from 25 oC to 35 oC the voltage and power is
plotted where due to increase in temperature the voltage decreases as result power decreases
(shown in fig. 8). Another most important parameter is light intensity because due bad environment
shadowing effect increased as a result light intensity changes. Depending on light intensity main
parameter is current as light intensity decreases the current also decreases and as a result power of
solar cell decreases (shown in fig. 9).
Fig. 8. Temperature effect in solar cell
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Modeling and Simulation of Solar Cell Depending on Temperature and Light Intensity
Fig. 9. Light intensity effect in solar cell
4. CONCLUSION
Environment is one of the most effect medium for reduction of solar cell efficiency. First
depending on temperature solar cell performance decreases. Temperature may damage the solar
cell. Increases in temperature reduce the band gap of a semiconductor, thereby effecting most of
the semiconductor material parameters.
The decrease in the band gap of a semiconductor with increasing temperature can be viewed as
increasing the energy of the electrons in the material. Lower energy is therefore needed to break the
bond. In the bond model of a semiconductor band gap, reduction in the bond energy also reduces
the band gap. Therefore increasing the temperature reduces the band gap [7]. The changing light
intensity incident on a solar cell and effects on cell parameters as the short-circuit current, the
open-circuit voltage, the FF, the efficiency and the impact of series and shunt resistances. A PV
module designed to operate under 1 sun conditions is called a "flat plate" module while those using
concentrated sunlight are called "concentrators"[7].
5. ACKNOWLEDGMENT
We would like to say thank to our parents because without their support and bless, we never reach
this position. After that we also want to say thanks to all of our friends who helped us on writing
this review paper and Jadavpur University for supporting software.
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Shivam Dubey, Lipi Sarkar, Rishav Roushan, Santanu Maity
REFERENCES
[1] Rohit Agarwal, ” Concept of Mechanical Solar Tracking System”, IOSR Journal of Mechanical and
Civil Engineering, 2278-1684, p-ISSN: 2320-334X PP 24-27, ICAET-2014
[2] http://en.wikipedia.org/wiki/Solar_cell_efficiency
[3] Cruz e Silva” Optimizing Energy Extraction of a Medium-Concentration Solar Panel”, Ph.D thesis ,
November 2011
[4] William Shockley and Hans J. Queisser. “Detailed Balance Limit of Efficiency of PN Junction Solar
Cells” Journal of Applied Physics, 32(3):510{520, 1961
[5] Andrew S. Brown and Martin A. Green. Impurity photovoltaic effect: Fundamental energy conversion
efficiency limits. Journal of Applied Physics, 92(3):1329{1337, 2002.
[6] LienaVilde,"MODELLING A PV MODULE USING MATLAB" 2010
[7] www.PVeducation.org
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Carbon Trading Scenario in India: A Business that
Works for Global Environment
Namita Rajput1, Vipin Aggarwal2, Ritika Ahuja3
1,2,32
Associate Professor, Sri Aurobindo College (D)
Namitarajput272gmail.com, [email protected]
3
[email protected]
3
Corresponding Author
1
ABSTRACT
In present scenario Global Warming is causing qualms and uncertainities for environment and
costing money as well. It has become a cause of global panic as its concentration in the Earth’s
atmosphere has been rising alarmingly. Green Environmentalists intend to to endorse business
and diverse policies that can help in the preservation and protection of natural environment. The
climate change and environmental conservation is the main issue of this century. India is the
second largest in world population and in energy consumption it is fourth largest and in green
house gas producer third largest and burns ten folds fuel wood as compared to United States. To
administer these emissions worldwide the environmental carbon trading practices are done on
the basis of the carbon credits earned.
In india the power generation is the biggest polluter and the biggest prospect for emission
reduction and hence can be the biggest carbon credits producers. India is generating the highest
number of carbon credits in the world next to china. In comparison to the developed nations the
carbon emission level in India is much less. This provides adequate opportunities for its
industries to produce carbon units and harness the benefits out of its trading. In India average
annual CERs (Certified Emission Reduction) stands at 11.5 million. India has great prospective
to earn carbon credits and in this context the carbon consultancy service has an enhanced part
to play and is going to add a new facet to the environmental arena.
Keywords: Carbon Credits, certified emission, green house producer, environmental carbon
trading.
1. SECTION I: INTRODUCTION
Emission of GHGs is becoming a major concern these days. There are various GHGs which are
emitted in the environment like CO2, Methane etc. CO2 is one of them and it is a major source of
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Somia Sharma, Kaushik Ghosh
problem for the atmosphere. The atmospheric life of CO2 is 5-200 years which has global warming
potential i.e. heat retention ability of gas as CO2 equivalent is 1. 3rd conference of parties was held
in Kyoto in Japan in which Kyoto Protocol was signed though it was ratified and it came into effect
in 2005. Excessive emissions of GHGs leads to global warming rise in temperature and sea level,
brings drought, leads to extinction of various species thereby threating whole eco system. To deal
with same Kyoto Protocol under U.N.F.C.C was set up in which countries in Annex I and Annex II
need to reduce their emission levels to the emission levels to the emission level permitted.
They can do it either by reducing emission levels to the emission levels in their own country or by
investing green technology in other countries thereby leading to zero net increase in GHGs in the
atmosphere. It can be either through Joint Implementation under which developed countries jointly
invest in green projects i.e. which is helping in reduction of emission in the atmosphere and thereby
achieving their targets or it can be done through C.D.M i.e. Clean Development Mechanism under
which developed countries who cannot reduce their emission, invest in developing countries to
become technologically competent as well as environment friendly and in return developed
countries earn various carbon credits for the same to achieve their targets.
2. SECTION II: CARBON TRADING
It is a mechanism through which countries that have to achieve their emission targets are achieved.
Carbon trading means trading of units of carbon dioxide reduced in the environment. Countries
which reduce carbon emissions earn Carbon Emission Certificates i.e. C.E.Rs which are traded and
is called carbon trading. One carbon credit is equal to 1 ton of carbon dioxide reduced in the
environment.
There are various exchanged in which carbon emission are traded like Chicago Climate Exchange,
NASDAQ OMX, POWER NEXT, European Energy Exchange etc. in India MCX and NCDEX are
two exchanges which deal with trading of carbon emission in form of Carbon Emission Reduction
Certificates which countries ern through completion of CDM projects or in form of ERU i.e.
Emission Reduction Units which are earned on successful completion of J.I. projects.
SECTION III: RECENT STATISTICS: as per recent statistics provided by U.N there are
currently 7366 registered C.D.M projects out of which 1444 are registered with India which was
4424 and 866 respectively in 2012. Following figure shows countries which are primary buyers of
CDM.
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Carbon Trading Scenario in India: A Business that Works for Global Environment
TRENDS IN CO2 EMISSIONS AMONG COUNTRY 2000-2012
(UNIT: BILLION TONS OF CO2)
country
United
states
EU27
Japan
China
India
2000
5.87
2001
5.75
2002
5.83
2003
5.87
2004
5.94
2005
5.94
2006
5.84
2007
5.91
2008
5.74
2009
5.32
2010
5.50
2011
5.39
2012
5.19
4.06
1.28
3.56
1.06
4.13
1.26
3.64
1.08
4.11
1.30
3.90
1.12
4.22
1.31
4.50
1.15
4.23
1.31
5.28
1.24
4.19
1.32
5.85
1.29
4.21
1.30
6.51
1.38
4.15
1.33
7.01
1.48
4.09
1.25
7.79
1.56
3.82
1.18
8.26
1.69
3.91
1.24
8.74
1.78
3.79
1.24
9.55
1.84
3.74
1.32
9.86
1.97
We can see that china is biggest emission of GHGs followed by America and EU27 but rate of
increase of GHGs emission in India more.
3. SECTION IV: CONCLUSION
So to conclude we can say that there are huge emissions in the environment. Various efforts are
being taken to conserve energy through improved promotion of energy efficiency devices, use of
renewable energy, reforms in power sector, use of clean and better and clean transport like CNG,
forestation, mass transport like metro which all help in achieving sustainable & clean environment.
SECTION V: REFRENCES:
[1] http://cdm.unfcc.int/statistcs/public/files/201301/cer_potential.pdf
[2] http://www.globalcarbonproject.org/carbonbudget/13/hl-full.htm
[3] http://www.globalcarbonproject.org/carbonbudget/13/hl-full.htm
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