BIOMASS POWER PLANT ON CAMPUS
Mayur B. Mahajan
B.E., Govt. Engineering College, Modasa, H.N.G.U., India 2006
Sagar R. Shah
B.E., St. Francis Institute Of Technology, Mumbai University, India 2006
PROJECT
Submitted in partial satisfaction of
the requirements for the degrees of
MASTER OF SCIENCE
in
ELECTRICAL AND ELECTRONIC ENGINEERING
at
CALIFORNIA STATE UNIVERSITY, SACRAMENTO
SUMMER
2010
BIOMASS POWER PLANT ON CAMPUS
A Project
by
Mayur B. Mahajan
Sagar R. Shah
Approved by:
__________________________________________________, Committee Chair
John Balachandra, Ph.D.
___________________________________________________ , Second Reader
Fethi Belkhouche, PhD.
____________________________
Date
ii
Students:
Mayur B. Mahajan
Sagar R. Shah
I certify that theses students have met the requirements for format contained in the
University format manual, and that this thesis is suitable for shelving in the Library and
credit is to be awarded for the thesis.
_________________________ , Department Chair
Suresh Vadhva, Ph.D.
Department of Electrical and Electronic Engineering
iii
________________
Date
Abstract
of
BIOMASS POWER PLANT ON CAMPUS
by
Mayur B Mahajan
Sagar R. Shah
California is recognized as one of the greenest states among all the states in Northern
America. Thus it is bound that California has lots of tree waste than any other states. On
the same lines, Sacramento is knows for city of trees, thus creating ones of tree waste.
These three wastes can be used to generate electricity with the help of Biomass Power
Plant. According to the biomass power industry in USA, California has highest number
of biomass plants.
The state government has realized the importance of generating energy through biomass
and therefore, governor has directed several state agencies – including the energy
commission to take major step towards widespread use of biomass to produce electricity.
California Biomass Collaborative (CBC) is joining hands with state agencies to expand
biomass power plant field. Above all, the governor has issued an executive order to
increase production of electricity using biomass. University of South Carolina (USC),
Columbus campus, has taken positive step towards biomass energy generation by
installing biomass power plant on their campus, which uses gasification system, first of
its kind in America. The plant saves millions of dollars every year on electricity.
iv
On the same line, California is blessed with all the input resources such as tree waste in
bulk, furthermore the state Government is also making step towards generation of bio
fuel. Then why California State University, Sacramento can’t have such kind of power
plant on our campus, which can save millions of dollars every year on electricity.
Considering the facts that there are numerous companies, which can invest on this project
collaborating with government companies such as California Energy Commission, public
interest Energy Research and SMUD can be sponsor’s for such kind of project. The
whole idea of this research is to lay the foundation of bringing biomass plant on our
campus.
_________________________________________________ , Committee Chair
John C. Balachandra, Ph.D
_______________________
Date
v
ACKNOWLEDGMENTS
It is our deep pleasure to thank everybody who has helped us in this project. Here we
would like to thank to Dr. John C. Balachandra, who has always encouraged us from the
day one. We reckon his extensive support and guidance throughout the project and even
in writing the report. Working with him on this project was a great learning experience
for us. Furthermore, he has taught us many practical aspects of research.
In addition, we would like to thank Professor Fethi Belkhouche for his precious guidance
in writing this project report. We would also like to thank Dr. Preetham B. Kumar,
graduate coordinator and Dr. Suresh Vadhva, department chair of the Electrical and
Electronic Engineering Department, for their valuable suggestions and support. I would
also take this opportunity to thank Nathaniel C. Martin, Energy Conservation
Coordinator, from Facilities Services. With his help we were able to collect all the
electricity usage information on our campus. At the same time we would also express our
thanks to Mr. Quinton Bolin, supervisor of the power plant at University of South
Carolina. Last but not the least, we are thankful for all faculty the members of the
Electrical and Electronic Engineering Department for helping us finish our requirements
for graduation at California State University, Sacramento.
vi
TABLE OF CONTENTS
Page
Acknowledgments …..…………………………………...………………………...…… vi
List of Tables..…………………………………………………..……………………….. x
List of Figures ………………………………………………………...………………… xi
List of Graphs …………………………..……………………………………………… xii
Chapter
1. INTRODUCTION ………………...…..…………..……………………………......… 1
1.1 Importance of Electricity. …………………………………………………… 1
1.2 Electricity Generation …………...……………………………………..……. 3
1.3 Need for Renewable Energy Production in United States................................ 5
2. BIOMASS POWER PLANT FOR GENERATING ELECTRICITY……….………...7
2.1 Different types of renewable energy source. ………........................................7
2.2 Why Biomass is preferred over other renewable energy source…...…………9
2.2.1 Sources of Biomass ……………………………………………...….............9
2.2.2 Sources to the Biomass power plant are locally produced………...…..........9
2.2.3 Biomass power plant reduces greenhouse gas emission………...……..…..10
2.2.4 Biomass power plant steady and dependable............................................... 11
2.2.5 Biomass power is the natural solution……………………………………..12
2.2.6 Few facts about Biomass power plant in United States………….....……...12
2.3 Role of US government for encouraging renewable energy….…….……….14
vii
3. GASIFICATION SYSTEM…..…….………………………….…………….….…..17
3.1 Overview- Biomass Gasification...……………………………….………… 17
3.2 Gasification technology……………….………..…….……...…..………… 17
3.3 Stages of Gasification………......….….……………….……………………19
3.4 General approach for a Biomass Gasification plant design........……………20
4. BIOMASS POWER PLANT AT UNIVERSITY OF SOUTH CAROLINA............22
4.1 Gasification System ………………………………………………………...22
4.1.1 Syngas.………………………….…………………………….....................23
4.1.2 Principle of Gasification System….………………...……………………..23
4.2 USC plant………………..……………………………..………………….....24
4.2.1 Fuel In-Feed System….……………………………….…………………...26
4.2.2 Gasifier……………….……………………………….……………………26
4.2.3 Ash Removal System.………………………………….…………………..27
4.2.4 Syngas………………………………………………….…….…………….28
4.3 Technical feature and benefits of this plant……….……….…….…………..28
4.4 Advantages of Nexterra Gasification……………………….…….…………31
5. BIOMASS POWER PLANT AT CALIFORNIA STATE UNIVERSITY,
SACRAMENTO…………………….……………………………………………… 33
5.1 Possible location of the plant….…........…….………...…………..…………33
5.2 Sponsors of the project ………………………………………………………35
5.3 Resources for the plant………….……………………………………………37
5.4 Cost of Installation and Workers ……………………………………………37
viii
5.5 Maintenance of the plant…………..……………………………………….. 38
6. SIMULATION AND CALCULATION……..……………………………………… 39
6.1 Matlab code for calculation of saving electricity..………........................... 42
6.2 Simulation result for calculation of saving electricity..……….....................43
6.3 Matlab code for energy utilization of Sac State on monthly basis………….45
6.4 Simulation result for energy utilization of Sac State on monthly basic…….45
7. CONCLUSION ……………………………………………………………................ 46
REFERENCES.…….………………….……………………………………….............. 48
ix
LIST OF TABLES
Page
1.
Energy consumption by major countries……………………………………… 2
2.
U.S. Energy Consumption. ……………………………………...………….. 13
3.
Sac State energy usage and cost….…………………………………………...39
x
LIST OF FIGURES
Page
1.
Renewable Energy Consumption in 2008…………………….……………..….14
2.
Basic process steps of a Biomass Gasification plant............................................18
3.
Three Basic Designs of fixed bed Gasifier with their characteristics of reaction
zones in each gasifier……..……………..……………………………………...20
4.
Nexterra Gasification System………………………………………….………..25
5.
Fuel In-Feed System………………………………………….………………....26
6.
Gasifier………………………………………….………………………………27
7.
Ash Removal System………………………………………….….…………….27
8.
Syngas…………………………………………………………………………. 28
9.
California State University, Sacramento campus map…….…,………………. 34
10.
Sponsors for the Biomass power plant…………………………...…………….36
xi
LIST OF GRAPHS
Page
1.
Greenhouse Gas Emission……………………………………………………….11
2.
PIE graph for operating cost of the plant……………………………………….. 43
3.
Relation between number of years and net operating income....…..…………… 44
4.
Energy Utilization of Sac State…………………………………………………..45
xii
1
Chapter 1
INTRODUCTION
In this chapter, we have elaborated different methods of electricity generation either
conventional or non-conventional. Also we have discussed what is a need of renewable
energy generation in United States of America.
1.1 Importance of Electricity
From ancient times to existing times, mankind progress has been relied on energy and
harvesting it and there isn’t any doubt that afterward next generation will also be
dependent on it. Because of its numerous usages in industry, agriculture, homes, and
transport, electrical energy immerses top position among all of the energy. It is
demanding for increasing agricultural production moreover domestic, commercial and
industrial purposes. Electrical energy is convenient form of energy as it can be generated
in large quantity and easily transmitted over long distances with high efficiency. To
measure the prosperity of nation, the usage of electricity per capita is considered as
benchmark. The quality of life, industry, and agriculture is much more relying on
electricity usage in this updated era. Developed and advanced nations have energy
consumption high per capita. Following is the per person energy consumption in KiloWatt Hour (kWh):
2
Country
Energy Consumption
(per capita kWh)
Argentina
2417.9
Australia
11,221.2
Brazil
2012.8
China
1,780.5
France
7,698.6
Germany
7,113.9
India
480.5
United Kingdom
6,233.9
United States of America
13,635.7
Table 1: Energy consumption by major countries [1]
From the above table it can be observed the per capita energy consumption is far
more in the developed and advanced nations like UK, USA, Australia, Germany, France,
than the developing nations like India, China, and Argentina. As mankind moves forward
in quest of better life, the energy consumption is all but set to increase in the future.
3
1.2 Electricity Generation
Developing nations like China, Brazil, and India have electricity usage, which is set to
accelerate for their better quality of life and better economies. Furthermore, the power
starvation for these countries is only ready to expand excessively with the rise in per
capita income and developments in all sectors. How this electricity is to be produced is
the most important factor. Below are some of the major requirements while looking at
electricity generation:

Low cost

Convenient

Easy Control

Cleanliness

Greater Flexibility
There are two kinds of electricity generation methods:
1. Conventional: The majority of electricity (greater than 70%) generation at
present is done by using conventional methods, namely:

Thermal

Hydro

Nuclear
4
2. Non- Conventional: The remaining 30% of energy generation is done by using
non-conventional method:

Solar

Biomass

Wind

Other non-conventional methods (geothermal, tidal etc.)
Oil (and its products) and coal still account for more than 50% of all electrical energy
produced. The major advantages using these fossil-fuel based electricity generation are:

Low cost fuel

Lower initial cost as compared to non-conventional sources

Reduced production cost

Ability to respond to rapidly changing loads without difficulties.
The major disadvantages are:

High maintenance and operating cost

Requirement of water in huge quantity (for steam power plants)

Handling of coal and ash disposal is quite difficult

Pollution of atmosphere due to fumes and residues

Efficiency falls rapidly below 75% of full load.
5
1.3
Need for Renewable Energy Production in United States
The expansion of renewable energy is migrating so rapidly because the urge for
alternative energy source is gaining instant. Various individual and research companies
are composing new and accelerating energy systems nationally and internationally.
The first and major problem is that the fossil fuels are dwindling instantly and are tough
to regain. If we are not cautious than we might be cladding energy disaster in near future.
Most of our energy is currently produced by burning Oil, Gas and Coal. But these
resources are finite. That’s why energy prices will be much higher and not available for
many individuals country. To avoid this critical situation, we have to find other ways to
produce energy and use them as much as we can.
The second problem is that our environment is getting damaged with extensive use of the
fossil fuels. People from early decades and even scientists have given serious advice
about fossil fuels, but anti effects are exposing today. The earth is heating up and
climates are also fluctuating. Some parts of the world are experiencing heavy rain while
other experiences drought. Another negative effect, which leads to heating of the earth, is
that the ozone layer is getting slimmer than ever before. Due to these crucial effects, we
will have to think in different direction, thus it will take us to the use of renewable
energy.
6
Small developing countries are facing more problems, as the energy prices for crude oil
are well above the sky; the rate of development is affected. Most of the developing
countries use crude oil for the generation of electricity and means of transportation. Due
to high oil prices, almost everything is affected on these countries. As compared to
transportation cost and prices for basic products, electricity cost for households increases.
Therefore small developing countries are facing problem to raise their economy due to
high oil price.
The renewable energy is the only solution for the above problems. Our lovely planet
gives us a contingency, to make proper use of flowing water, winds, hot springs seasons,
sunlight that can be converted to generate electricity. These energy sources are ample and
available to us at free of cost. So, we must have to convert the energy in right way, so that
it will not damage our environment. We won’t get to the stage of “using the renewable
energy all up”. [2]
7
Chapter 2
BIOMASS POWER PLANT FOR GENERATING ELECTRICITY
2.1 Different types of renewable energy source
This part elaborates various types of renewable energy and its production process. There
has been lots of development and research in the renewable energy market is going on,
and that is why, generating environmentally efficient and clean power is very easy
nowadays. Before we select what type of renewable energy method, we should go
through our options that are available. This will help us understand where renewable
energy market stands and is heading in which direction.
Here are the various types renewable energy source

Hydropower: “The power of water is abundant by approximately 73 percent of all
renewable energy according to the Energy Information Administration.” [3] With
the help of Mechanical energy of flowing water, Hydropower is generated; it is
accomplished by forcing it through piping. This flowing water produces
electricity by generator. Wave and tidal energy are also considered vital source of
hydropower system. Currently research is under progress of how they can use
8
wave and tide to generate energy more efficiently. The Hoover Dam is to be
considered as one of the largest hydropower unit in the United States of America.

Solar Power: Photovoltaic cells plays vital role in production of solar energy.
These cells are made up of silicon, which absorbs radiation from the sun. It
creates electricity by movement and displacement of electron, which are caused
by absorption of radiation from sun. But some system also uses large mirrors to
heat the water and to generate steam, which in turn is used to run a generator.

Wind Power: Generating power using wind is very clean and simple process.
Electricity is generated by the conversion of motion energy (Kinetic) to
mechanical energy with the help of wind turbine. The energy is converted second
time into electrical energy using generator. This is then fed to the power station
via grids. California and Texas has abundant wind power. Wind power is very
unique, since it carries incentives for farmers, which gives parcels of land for
making wind turbines. Also we have large areas of land which are unused, that
can be used to harness.

Geothermal Power: In this process, energy is created near the surface in the form
of heat, by trapping heat underground. The steam turbines are used to generate
electricity and thus hot water is created by this heat. The geothermal energy for
commercial purpose was first used in the early 1900’s in Italy.
9

Biomass: It is a flexible form of energy. This process involves, burning of
biomass fuel in boilers to heat water, which in turn are used to turn a steam
turbine to create electricity. Various types of biomass fuels are discussed below,
but most common are wood to land fill trash. Various researches are under way as
how raw manure can be used to generate energy. [3]
2.2 Why Biomass is preferred over other renewable energy source
2.2.1 Sources of Biomass
The main advantage of biomass power plant is its sources are very commonly available.
Some of sources of biomass are wood, wood chips, trash, corn maize, sugar cane, canola,
sunflower, soy beans, switch grass, animal waste, manure, sewage, hemp, grains, wheat
straw, vegetable oil, paper, and many more.
2.2.2 Sources to the Biomass power plant are locally produced
A major proportion of its energy needs created from the locally produced, renewable
sources will be something different compared to the present one. Only in few countries,
the fossil-fuel dependent global economy is beholden to producers. The big price rises of
crude oil influences, inflation rates, currency values, interest rates, and therefore
standards of living. Oil-producing countries have the power, as they are the biggest
10
source of barrel. Just like the petro-chemical industry, many of the biomass crops have to
be produced by the agricultural sector and biomass energy production can involve byproducts such as fertilizers. To drive their equipments and vehicles, farmers can produce
the energy. Domestic farmers would have far greater control over their cost of production
and energy-based powers, which are centrally based, but will transformed into locally
based power. Thus the control of energy food production will be in hands of poor farming
sector. Nobody knows what could be the possible impacts of such an important power
shifts would be. Energy would no longer be a factor for international conflicts.
2.2.3 Biomass power plant reduces greenhouse gas emission
Methane gas and carbon dioxide are slowly emitted, as organic waste decomposes. The
advantage of this process of turning waste into fuel is taken by biomass power plants.
Carbon dioxide emissions are cut down and methane gas is extinguished, during the
electricity generating process. Greenhouse gases are actually cut down by biomass. Over
30 million tons of carbon dioxide is removed annually with the use of biomass power
plant. By replacing fossil fuels and by forestalling the release of greenhouse gases from
organic waste, which could otherwise decompose in the open atmosphere, makes possible
to accomplish this remarkable feat. Following is the graph, which illustrates the
atmospheric greenhouse-gas profile over time, is very different for the energy production
alternative.
11
Graph 1: Greenhouse Gas Emission [4]
From the above graph, it is clear that greenhouse emission is comparatively lower than
other fossil fuel.
2.2.4 Biomass power plant is steady and dependable
Changes in weather or environmental conditions do not affect biomass power plant
generation process. This plant is very dependable renewable energy source. A steady and
dependable flow of electricity can be expected from biomass over 24 hours, and seven
days a week. Base load supply to meet growing energy demands of local utility
companies can be fulfilled by the reliability of biomass power plant. Therefore the
12
consistency of this plant makes it superior than other types of renewable energy power
plant.
2.2.5 Biomass power is the natural solution
“Biomass power is an expanding $1 billion industry with 80 facilities in 20 states that
supplies over half of America’s renewable electricity and nationwide, the biomass
industry accounts for over 18,000 jobs, many of which are in small rural communities.”
[5] Biomass is turning out to be a natural solution to meet the higher renewable standards
as America is making an important commitment to renewable energy. States in southeast
that lack access to wind or solar power, biomass can play a significant role in such areas.
2.2.6 Few facts about Biomass power plant in United States
Table below illustrates United States energy consumtion over few years and types of
sources which have been used to generate energy. It can be clearly seen that from all the
reneable energy sources, biomass is the most preffered energy generation method.
13
U.S. Energy Consumption by Energy Source
Renewable Energy Consumption and
Electricity Preliminary Statistics, 2008
Release Date: July 2009
Next Release Date: July 2010
Table 1 U.S. Energy
Consumption by Energy
Source, 2004 - 2008
(Quadrillion Btu)
Energy Source
Total
Fossil Fuels
Coal
Coal Coke Net Imports
Natural Gas1
Petroleum2
Electricity Net Imports
Nuclear Electric Power
Renewable Energy
Biomass3
Biofuels
Waste
Wood Derived Fuels
Geothermal Energy
Hydroelectric Conventional
Solar/PV Energy
Wind Energy
2004
100.349
85.830
22.466
0.137
22.931
40.294
0.039
8.222
6.260
3.023
0.513
0.389
2.121
0.341
2.690
0.065
0.142
2005
100.485
85.817
22.797
0.045
22.583
40.393
0.084
8.160
6.423
3.133
0.594
0.403
2.136
0.343
2.703
0.066
0.178
2006
99.876
84.690
22.447
0.061
22.224
39.958
0.063
8.214
6.909
3.361
0.795
0.414
2.152
0.343
2.869
0.072
0.264
2007
101.552
86.174
22.748
0.025
23.628
39.773
0.106
8.458
6.814
3.597
1.025
0.430
2.142
0.349
2.446
0.081
0.341
2008
99.305
83.436
22.421
0.040
23.838
37.137
0.113
8.455
7.301
3.884
1.413
0.431
2.041
0.358
2.453
0.091
0.514
Table 2: U.S. Energy Consumption [6]
As per EIA (Energy Information Administration), Total Energy consumption in US is
99.305 Quadrillion Btu in 2008, and 7% (which is almost 7.301 Quadrillion Btu) came
from renewable energy. Out of these 7% of renewable energy 53% comprises of biomass.
14
Figure 1: Renewable Energy Consumption in 2008 [7]
2.3 Role of US government for encouraging renewable energy
“US government is making efforts for the construction of alrernative energy eighter by
buisness or through direct payments and by making rules and regulations. ARRA
(American Recovery and Reinvestment Act), the Department of the treasury and the
Department of Energy are accepting application for a program called “1603 Program” to
make direct payment to companies that create and put is place renewable energy
facilities.” [8]
Governor Arnold Schwarzenegger recently signed an Executive Order (EO) advicing the
California Air Resources Board (CARB) to make regulations regarding increase in
California’s Renewable Portforlio Standard (RPS) to 33 percent by the year 2020 and
15
also advacning California’s commitment to reduce greenhouse gas emmision and
increase the states’s renewable energy. The various state laws regarding renewable
energy is explained below:

Executive order s-21-09
The best renewable energy resource areas in the world, which can be accessed by
California, providing immense potential for clean, valuable electricity generation,
and the development of these resources must be speeded and maximized. To
increase the total acquirement of eligible renewable energy resources by at least 1
percent per every year, Senate Bill 1078 was launched, so that 20 percent of their
retail sales is acquired from eligible renewable energy resources by 2017.
Acceleration of the RPS (Renewable Portfolio Standard) was called in 2003 by
Governor Schwarzenegger, appealing that rather than 2017, 20 percent of
California's electricity should come from renewable sources by 2010. This
standard became law in 2006 when Senate Bill 107 was signed by Governor. The
Advantages of producing electricity from renewable resources provides multiple
benefits to California's environment and economy. Also it helps to improve air
quality, health of the public, reduces global warming, improves energy security,
economic development and finally creates employment. [9]
16

Executive order s-14-08
This executive order launches a target that all retail sellers of electricity shall
provide with 33 percent of renewable energy by 2020. While all the publically
owned utilities should provide with significant amount of electricity and a
statewide effort should be included to reduce greenhouse gases from their systems
such that recognize their individual circumstances. [10] Government has awarded
$503 million for renewable energy projects. On Tuesday, September 1st 2009, the
US Energy and Treasury Departments announced $503 million cash grants to
companies working on renewable energy projects. This funding will be used
towards the goal of doubling US renewable energy production in the next three
year during Obama’s administration. As per the department of energy, to achieve
a 3 percent increase in total US renewable electricity generation capacity it will
require to have 12 projects that should be able to produce 840 megawatts of
electricity. [11]

Biomass power association
On 20th August 2009 the Biomass Power Association (BPA), which is the
nation's top association of biomass power plant companies, announced to launch
$250,000 public relations, advocacy, and advertising campaign to promote the
importatnt role of biomass power plant which can play in reducing greenhouse
gases and creating lots of new jobs across America, specifically in rular area. [12]
17
Chapter 3
GASIFICATION SYSTEM
3.1 Overview – Biomass Gasification
For the production of heat and power based on biomass, gasification is an alternative
option of thermal biomass utilization. There are various types of gasification technologies
are present with their demonstration plants. With the experience from these
demonstration plants, it has helped a lot to develop the gasification technology even
further. Due to this reason, few gasification technologies are almost ready to hit the
market.
3.2 Gasification technology
As discussed earlier, this plant is based on gasification technology. Several process steps
are included in gasification plants, which are as shown in Figure 2. First of all, the fuel,
which is in solid form of biomass delivered needs to be, changed which is called as fuel
conditioning and handling. The fuel needs to be conditioned for the gasification process
to achieve the desired fuel characteristics (particle size, water content). This conditioned
fuel is then passed through the gasification process, which produces raw product gas, also
called as syngas. For further utilization, this raw product gas is required to be cleaned so
18
that it achieves the product gas quality needed. Finally the cleaned product gas can be
used for the production of, heat and electric power depending upon the requirement.
Conditioned
Fuel
Raw
Fuel
Fuel
Conditioning
andtransport
* Chipper
* Dryer
* Screens
* Mills
* Fuel feeding
System
* Stoker Unit
Gasificatio
n
Process
* Fixed bed
-countercurrent
-Co-current
* Fluidized bed
-Stationary
-Circulating
-Two-bed
* Entrained flow
* Multi-stage
Raw
Gas
Gas
cleaning
and
conditionin
g
Clean
Gas
* Cyclone
* Tar cracker
* Gas cooler
* Ceramic filter
* Bag filter
* Gas Scrubber
* ESP
* Compressor
* Shift-reactor
Heat
Gas
Electricity
Utilization
Fuel
* Burner
-Boiler
-Furnace
-Co-Firing
* Gas engine
* Gas turbine
* Fuel cell
*Combined
process
* Synthesisreactor
* Feed-in into
gas grid
Figure 2: Basic process steps of a biomass gasification plant [13]
Here the process steps are shown in rectangle while the conversion stages of the fuel
during the gasification are displayed with the help of arrows. Different technological
options for each process step are shown in the rectangles below.
Solid biomass is break down by thermal energy and a fumigator and is altered into a
product gas, during the thermo chemical gasification process. This product gas is further
cleaned so that it can be used for the production of heat and power. One of the advantages
of the biomass gasification technology is that it has the utmost electric efficiency because
19
of the power production with gas engines. Various alternate applications of the product
gas are possible such as production of fuel or feed it into the public gas grid.
In order to increase the electric plant efficiency and to generate additional electricity, the
high waste heat from the gasification system and the gas engine are useable in an ORC
unit. While the low temperature wastes heat is usable for biomass fuel drying. High
overall
plant
efficiency
can
be
achieved
by
efficient
heat
utilization.
3.3 Stages of Gasification:

Drying

Pyrolysis

Oxidation

Reduction
There are mainly two different types of gasification technology available and they are in
fixed bed gasifiers and fluidised bed gasifier. As the name says fixed bed, it means the
fuel particles here are not moved by the flow of the gas. The feeding of the fuel in most
cases is placed above the fuel bed while the ash and charcoal are taken out from the
bottom of fuel bed. The biomass fuel stays relatively longer time in the gasifier as the
fuel moves from the top to the bottom of the fuel. Fuel feeding from below the fuel bed
can be achieved by a special design of fixed bed gasifiers. The fixed bed gasifiers are sub
divided into counter-current, co-current or cross flow gasifiers, depending on the
20
direction of the product gas flow comparative to the direction of the fuel transport.
Figure. 3 below summarize the three basic designs of fixed bed gasifiers with their
characteristic of reaction zones in each gasifier.
Figure 3: Three basic designs of fixed bed gasifiers with their characteristic of reaction
zones in each gasifier [14]
3.4 General approach for a biomass gasification plant design

Comparison of different biomass gasification technologies with respect to
technical and economical assessment for the selection of an adequate technology.

Planning of woodchip resource for internal heat supply, heat recovery and power
production based on the ORC process.

Study of feasibility, and economical consideration of the actual plant.

Design of plant preliminary.
21

Preparation of permit and its applications

Request for proposals with the help of detailed design and simulation.

Actual plant construction, supervision and commissioning.

Finally, monitoring of the plant, process and enhancement.
22
Chapter 4
BIOMASS POWER PLANT AT UNIVERSITY OF SOUTH CAROLINA
To promptly use the available fuel in an innovation plant on campus, University of South
Carolina comes to conclusion for the best way to meet its ultimatum to integrate
renewable energy. In the United States the first of its type, for the raw material the plant
practice sufficient wood fiber. To cut down the costs for steam and electricity, the
university considers many solutions. The USC faculty and staff were dealing with same
kind of problem, which they found through Johnson Control Inc and Nexterra, a
Canadian based company in Vancouver. Nexterra is a manufacturer and supplier biomass
gasification systems and solutions. Nexterra supply the components for a plant that
process wood waste material into syngas, a gas combination that involves separate
amounts of carbon monoxide and hydrogen.
4.1 Gasification System
The Gasification is a thermo-chemical process that alters the heat to convert any carboncontaining fuel into a clean burning gas called “syngas”. For complete fuel combustion,
gasification adopts just 20% – 30% of the air or oxygen as compared to combustion.
Even a small portion of the fuel melts completely in the gasification system because the
23
gasifier is precisely supervised the amount of air. This “starving air” combustion process
produces transformation of a compound caused by heat and chemically breaks down the
balance of the fuel into “syngas”.
4.1.1 Syngas
Syngas is primarily made of methane, hydrogen and carbon monoxide, as well as
dissipate transformation of a compound caused by heat, liquids and hydrocarbon. Syngas
is a fresh flame fuel that can be used as substitute for hot water, electricity using
conventional energy recovery equipment, steam, natural gas, fuel oil or propane to
produce process heat. Synthesized syngas utilized as basic chemical building block for
plenty of products in the petrochemical and refining industries.
4.1.2 Principle of Gasification system
Over the 200 years, the gasification system principle has been tolerated. In late 1800s,
Coal gasification was used for lighting and power generation. After the World War II, a
low cost oil and gas prosperity resulted in downfall for gasification. Due to growth of
fossil fuel and electricity costs, gasification has faced a restoration in recent years. One of
the most efficient, cleanest and versatile ways to convert wood sewage and coal into
thermal energy or electricity is recognized as gasification.
24
4.2
USC plant
Nexterra Gasification Technology
To deliver heat and power at plant-scale application, Nexterra’s gasification technology
transforms wood and other solid fuels into syngas. Using wood fuel in panel board plants,
paper mills, pulp and sawmills, Nexterra has initially established gasification systems to
expel natural gas. Some systems that run on coal and other low cost fuels will be covered
in future applications.
Fixed bed, updraft gasifier is the technology used in Nexterra. Fuel is bottom-fed into the
centre of the curving and somewhat round in shape, figured to 3 inches or less, rigid
reinforced gasifier. The base of the fuel pile is come out by combustion air, steam and/or
oxygen. At 1500- 1800°F partial decomposition, gasification, and transformation of
compound caused by heat take place and the fuel is converted into non-combustible ash
and “syngas”. From the base of the gasifier, ash travel to another place and is finally
removed once in a while through an automated in-floor ash spin. In order to produce
useable hot water and/or electricity, heat, the energy recovery equipments manages the
clean syngas or to set on fire directly into boilers, dryers and kilns.
25
Figure 4: Nexterra Gasification System [15]
26
4.2.1 Fuel In-Feed System
In order to accommodate short-term fuel storage and to convey a uniform rate of fuel to
gasifier, the metering bin is patterned. The metering bin transfers fuel into a horizontal
grill conveyor at a variable speed, and it is shifted to a vertical conveyor. The fuel is then
pushed into the base of the fuel drift inside the gasifier by the vertical grill. During the
entire operation range, a constant fuel drift height is retained in the gasifier.
Figure 5: Fuel In-Feed System [15]
4.2.2 Gasifier
After entering into the gasifier, the fuel flows through continuous stages of drying,
transformation of a compound caused by heat, gasification and degradation to ash. Inside
the base of the fuel drift, combustion air (20 - 30% of reactance and production in
chemical reaction), steam and/or oxygen come out through the inner and outer cone.
27
Simultaneous control of combustion air and fuel feed rate retain the process. In order to
make sure that there is no deposition of “clinker” (the incombustible residue that remains
after combustion of coal); combustion temperatures are rigidly overlooked in the fuel
drift and reserved below the ash melting temperatures and so that the ash flows freely.
Figure 6: Gasifier [15]
4.2.3 Ash Removal System:
Fuel is dwindled to non-explosive ash while it ravine to the outer cone. Though a set of
openings, the ash is eliminating occasionally while it shifts to the grate at the base of the
gasifier. A rotating plate typically wraps the openings and it is piece together with the
same pattern of openings. The rotating plate adjusts its openings with the fixed plate
when it is operated by fuel energized and the ash slides into two ash hoppers. To conduct
the ash each ash hopper has two parallel grills to a collection conveyor and wrapped ash
bin.
28
Figure 7: Ash Removal System [15]
4.2.4 Syngas:
At 500 - 700°F syngas survives the gasifier. The syngas can be reduced to ashes in a
close-coupled oxidizer, where it results in a flue gas, which is guided to heat recovery
equipment. Boilers, thermal oil heaters, air-to-air heat exchangers and turbines are used
for heat recovery equipment. To ignite syngas directly, Nexterra is expanding systems
into industrial boilers, kilns, dryers and other equipment.
Figure 8: Syngas [15]
4.3 Technical features and benefits of this plant
29
 Clean Syngas
Heat exchangers stay clean and need less maintenance and spare time as Nexterra
gasifiers form an exclusively clean syngas. Drying applications such as veneer dryers,
lumber dry kilns, boilers, lime kilns, rotating dryers and fire heating can be directly set
a flamed by clean syngas.
 Low Particulate Emissions
Low particulate emissions construct by Nexterra gasifiers used for air pollution control
equipment such as multicones, electrostatic precipitators or bag houses rely on the fuel
type and inquisition.
 Design Simplicity
As compared to conventional combustion systems or fluidized bed gasifiers, Nexterra
systems are simple in design because it has few moving parts. No need for multiple ash
collection points. Pollution control equipment or grate cooling systems is also not
required. So overall power consumption and capital cost is reduced. And less
maintenance required.
 Free Flowing Ash
To control the temperature in the fuel bed, below the ash melting point, is done by
tightly controlled combustion. In conventional combustion systems, clinkering issues
are encountered which are terminated in this system, and propagates a highly rough in
30
quality, easily flowing ash.
 High Turn-Down Ratio
While maintaining the stable operation, the output of the gasifier can be stepped down
to less than 20 % of its maximum capacity.
 Idling Capability During Low Load Periods
In order to remain on standby for extended period of time such as a weekend
shutdown, without wasting fuel, and then be retrieve to full capacity within two hours,
Nexterra gasifiers quickly decrease the effort involved into the process into an idling
mode. By this way fuel can be managed, shutdown can be shuffle off and restart during
periods of low heat demand.
 Fuel Flexibility
Nexterra gasifies may also be accommodating for other biomass fuels. It can also
contain a wide range of wood fuels including bark and white wood sized 3-inch minus
with moisture content up to 60%.
 Low Gasifier Temperature
For most fuels during normal operation, gasifier temperature above the fuel pile will
freeze well under 1000°F. Due to low temperature, it results in long lasting willful.
That’s why refractory require less maintenance as compared to other combustion
31
systems.
 Easy and Automated Operation
The control system is achieved to maintain safe and efficient operation of energy
system. With state-of-the-art PLC controls, Nexterra systems are fully programmed.
4.4 Advantages of Nexterra gasification
Nexterra gasification technology is preferred in another way for industrial energy system
applications as it has lots of advantages over the combustion systems.
 Low capital cost
As Nexterra’s energy systems model is simple, contains less equipment and has less
moving parts, its capital cost is low. Emission control equipment such as multicones
and electrostatics precipitators are not necessary in this system. As compared to
conventional combustion systems, the ash collection system is also effortless, less
valuable and easier to operate. Water cooled grates and transfer points are not required
in gasifiers. Multiple ash collation is also not required in this system.
 Low O&M Cost
Due to their simple design and requirement of less equipment, Nexterra systems are
less valuable to operate and retain. In the gasifier, gas velocities are lower and
temperature is also much below hence result in longer life and less rigid maintenance.
32
In the end, cleaner flue gas result in less frequent, faster and easier cleaning of heat
exchanger surfaces.
 Syngas Versatility
As compared to conventional combustion equipment Nexterra gasifiers are more
versatile. Syngas is flexible fuel. Heat recovery equipments like kilns, dryers, lime
kilns and boilers use syngas to fire up. Also, syngas is advantage for cooling and
shrinking or pass out multiple users on the single site.
 Simple, Easy operation
Nexterra gasifier systems have simple model, superior operational control, high
turndown ratio, idling capability, syngas control and ability to eliminate ash melting.
Also, Nexterra gasifier systems are very simple and easy to operate.
33
Chapter 5
BIOMASS POWERPLANT AT CALIFORNIA STATE UNIVERSITY,
SACRAMENTO
In this chapter, we have discussed what are the prospective of biomass power plant on
campus, its advantages, saving on energy generation after installing the plant and location
of plant on campus. In all the above chapters we have discussed as how biomass is the
best for generating renewable energy over other source. Also we have discussed that it’s
now an official state law that certain percentage of energy should come from renewable
source. And also we have the resources ready for such kind of power plant as discussed
before that Sacramento and California is blessed with the trees and thus tons of tree
waste. Furthermore, we also have funding from various sources that can help the project
to establish the energy need at Sacramento state university. So now we have resources,
official law and sponsors, than why Sac State cannot have a biomass power plant on
campus like the one at University of South Carolina.
5.1 Possible location of the Plant
34
In the section we have discussed the possible location of the biomass power plant on
campus or it should be located off campus but near the campus.
35
Figure 9: California State University, Sacramento Campus map [16]
36
Figure above shows the campus map of California State University, Sacramento. We
have talked to Mr. Martin about the possible location of the plant on campus. After going
through all possible plant location on campus, we came upon location close to Modoc
hall, which is student lot, 9 and lot 10, located on the top right corner of the map.
Currently this space is used for car parking, and most often this lot is empty, thus we can
use this space for possible plant location on campus itself. The total area needed would be
around 39,000 sq. ft. The plant needs all the waste wood chips, which are available in
abundant near Sacramento county, Furthermore on our estimation university’s biomass
plant will take benefit of some of the state's 21 million tons of waste wood chips each
year. The number could vary depending upon the usage.
5.2 Sponsors of the project
With so much enforcement by the government, to generate energy via renewable means,
many organizations are coming up with sponsorship of such kind of project. Here we
have not discussed the idea of the project with any of the sponsors due to lack of time.
But we are very sure, if we would have proposed this idea in front of some sponsors, we
would have definitely received some positive feedback. Still we have presented some list
of the sponsors that are affiliated to the California Biomass Collaborative.
Furthermore, California State University, Sacramento, is a part of the California State
System, we could also consider, State of California as one of our sponsor. With various
37
laws from the California governor, we consider that state will play a vital role in
sponsoring such kind of project. Furthermore, considering the fact that Obama
administration has released millions of dollars to encourage generating renewable energy.
The only things here we can just assume for the funds from sponsors below, considering
that we have presented this project in front of them effectively, so that they are impressed
with it.
Figure 10: Sponsors for Biomass Power Plant [17]
38
5.3 Resources for the Plant
There are numerous resources that can be used for the biomass power plant. Resource s
comes from agricultural sector, forestry biomass, municipal wastes and future dedicated
biomass crops. “Biomass resources in the state totals 83 million gross bone dry tons per
year (BDT/y) at present and are projected to increase to 98 million BDT/y by 2020.” [18]
Biomass resources are considered to be available on a technically sustainable basis. The
plant at university at South Carolina has used in field chipping mixture of hardwood and
softwood, which are less than 4" in size. Thus such kinds of resources are locally present
in northern California. Johnson Control at USC is purchasing fuel at approximately $22
per ton for full operation, while the plant uses 57,000 tons per year.
5.4 Cost of Installation and Workers
As per Our resources and size of the plant, the cost of installation should range between
$18 -$20 million. The amount might vary depending upon the cost of certain product type
installation. Furthermore, the cost includes the construction of the plant building and also
other affiliated things like parking for staff and workers, inspection room, and restrooms.
While the maintenance of the plant will be depended completely on contractual basis.
The maintenance of the plant at the USC is also on contractual basis with Johnson
Control Inc. And thus the cost of the maintenance depends on the output requirements of
39
our campus and size of the plant. The plant will require maximum of two people working
at any given point of time and one supervisor.
5.5 Maintenance of the plant
In order that the plant should operate in ideal way, it has to carry out maintenance. It can
be done at certain period in the year and so we need at least 15 days to completely shut
off plant, which includes maintenance period time and also some critical emergency shut
off time. Here we have analyzed different times of the year and found that winter season
has the least requirement for energy as compared to other seasons of the year. As shown
in the simulation par, month of February is the low power-consuming month. Thus, we
are allocating each season into 90 days and keeping winter as 80 days. With this spring
has 90 days, summer has 90 days, autumn will have 90 days and winter has 80 days.
Therefore, the total working days of biomass power plant will be 90+90+90+80 = 350
days + 15 days of maintenance or critical shut down. So now we have calculated the
energy generated KwH per season using this formula: Pe season = Ped * No. of days in that
season.
40
Chapter 6
SIMULATION AND CALCULATION
In this chapter, we are trying to show how such kind of power plant on campus can be
economical for generating electricity. We have collected the Sac state energy utilization
detail from Nathaniel C. Martin. He is Energy Conservation Coordinator, Facilities
Service at Sacramento State University. Here is the detail of Energy usage and Cost.
Jun
Jul
Aug
Sept
Oct
Nov
Dec
Jan
Feb
Mar
Apri
May
Sac State
energy usage and cost
FY0809
kWh
3,957,915
3,501,619
3,755,606
3,723,858
3,996,593
4,110,859
3,393,498
3,167,073
3,121,514
3,288,755
3,803,235
3,834,322
43,654,847
FY0809
cost
$280,459
$308,216
$337,325
$337,399
$358,587
$283,921
$254,205
$242,741
$233,614
$245,228
$275,670
$273,567
$3,430,932
FY0809
kW
8760
8760
8760
8760
8760
8760
8760
8760
8760
8760
8760
8760
FY0809
Therm
10355
12422
11731
20051
51317
147404
201044
220872
186043
171132
127079
52726
1212176
FY0809
Cost
$13,874
$18,379
$14,952
$21,688
$45,886
$127,352
$166,081
$186,661
$151,951
$122,502
$95,172
$40,164
$1,004,662
Table 3: Sac State energy usage and cost from Nathaniel C. Martin
41
Furthermore, we have collected data from the plant at University of South Carolina from
Quinton Bolin, he is the supervisor in charge of the plant. Before we did the simulation,
here are the considerations we have made with reference to our research:

Cost of the plant installation: $18 million.

Amount of wood chip needed annually: 57,000 ton

Cost of wood chip $22 per ton, so Wood chip will annually cost $1,254,000

Number of workers needed: two and one supervisor

Thus cost on manpower annually: $100,000 ($25000 * 2 +$50000)

Maintenance cost of $50,000.

And other cost includes, Permit fees and application of $20,000
After installing the power plant on campus, we consider that sac state will have to shut
off its two boilers out of three. And will only have to run one boiler of 20,000 lbs per
hour. So we are cutting down cost by 80% as we are shutting two boilers each of 40,000
lbs per hour. At present sac state pays almost $3.6 million on electricity. Thus 80% of
$3.6 million is $2.88 million. Thus after installing the plant we will pay only $0.72
million for conventional means of source. While Biomass power plant’s cost will be $1.4
million annually. So the total cost on energy generation would be $1.4 +$0.72 = $2.12
millions.
Annual saving after the installation of the plant = previous cost – new cost
= $3.6-$2.12
= $1.48 millions of saving annually
42
Thus if we calculate the Breakeven point, it will be $18millions/$1.48 million = 12.16
After 12.16 years, the installation cost of this project can be covered up. And thereafter
it’s all profit for campus. The same calculations are explained in matlab simulation with
the pie graph.
43
6.1 Matlab Code for calculation of saving electricity:
clear all
% Deleting all figures whose handles are not hidden.
close all
% Deleting all figures including those with hidden handles.
close all hidden
% Clearing all input and output from the Command Window display giving us a clean
screen.
clc
woodchip_cost=22;
woodship_qty= 57000
input_woodchip=woodchip_cost*woodship_qty;
initial_cost=18000000;
operating_cost=2*25000+ 50000;
maintaince_cost=50000;
others=20000;
h=pie([operating_cost
others
input_woodchip
],{'Operational.','Misc','Woodchip','Maintaince'});
pause;
close;
for i=1:20
current_energy_bill=(1.4+.72);
conventional_bill=3.6;
sav=conventional_bill-current_energy_bill;
saving(i)=sav*i-18
end
break_evenpoint=18/sav
plot(saving)
grid on
maintaince_cost
44
xlabel('Number of years')
ylabel('Net Operating Income')
6.2 Simulation Result for calculation of saving electricity
Graph 2: shows the pie graph for operating cost of the plant.
45
Graph 3: shows the relation between number of years and net operating income.
The net operating income would be in positive after 12. 16 years. That point is called as
breakeven point.
This part of the matlab code shows the bar graph for sac state energy utilization in
monthly basis. This helps us to find out in which month campus requires the lowest
energy and thus will help us to carry maintenance of the plant.
46
6.3 Matlab Code for Energy utilization of Sac state, on monthly basis.
X=[3957915 3501619 3755606 3723858 3996593 4110859 3393489 3167073 3121514
3288755 3803235 3834322];
%y=[];
set(gca,’XtickLabel’,{‘June’, ‘July’, ‘August’, ‘September’, ‘October’ ,’November’,
‘December’, ‘January’ ,’February’ ,’March’, ‘April’ ,’May’})
bar(x);
6.4 Simulation Result for Energy Utilization of Sac state, on monthly basis
Graph 4: shows the energy utilization of sac state.
Y axis represents energy in Kwh
X axis represents months. 1st months being June, and 12th month being may.
Month of February would be ideal for the maintenance of the plant.
47
Chapter 7
CONCLUSION
The main purpose of using biomass for generating energy is because, its resources are
available in abundant and are locally produced. Furthermore, biomass helps in reducing
greenhouse gas emission. We can rely on biomass power plant as it is considered to be
dependable and a natural solution. It is the most common means for generating renewable
energy among all the various methods available. Even the state government of California
is encouraging to generate some portion of energy via renewable means, which are stated
in executive law. Thus to achieve the goal mention in the executive law, various
government sectors had released funds to sponsor and encourage such type of projects.
University of South Carolina has taken a positive step in installing power plant on their
campus. It helps to save almost $2million every year on generation electricity. The
gasification technology used for this type of power plant is new in northern America and
is more fruitful than conventional method.
California is blessed natural resources, and especially Sacramento is known for city of
trees. Thus, we will have tons tree waste, which can be used to generate electricity
through biomass. In this project, we have tried to lay a foundation of installing a biomass
power plant on campus, considering its possible location on campus, cost of installation
and maintenance. Also we have gathered campus electricity usage from facilities
services, which helped us to determine economical aspect of the project. Our calculation
48
and simulation shows how our campus can save millions of dollars on generating
electricity every year. As per our results in simulation, it will save $1.48 million annually.
49
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50
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51
[17]
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http://biomass.ucdavis.edu/sponsorship.html
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