ENERGY SUPPLY
MICRO AND DISTRIBUTED GENERATION
AND TRIGENERATION I
Prof. dr. Marija Todorovic
DERES - DIVISION FOR ENERGY EFFICIENCY AND
RENEWABLE ENERGY SOURCES
Faculty of Agriculture, University of Belgrade, Serbia
deresmt@EUnet.yu, deres@agrifaculty.bg.ac.yu
www.rcub.bg.ac.yu/deres
2006 6th November
AIM OF THIS LECTURE
Introduction to the relevant definitions and aspects of the combined heat &
power (CHP), micro and distributed generation and trigeneration for all
UNESCO E-Learning target groups,
Its aim is to provide an understanding of power generation technologies and
to show how “waste” heat from electricgeneration process can be used for:
heating and/or cooling to increase systems integral energy efficiency, to
reduce operating costs and the need for new electric utility construction,
as well as to reduce the load on electric transmission systems.
It is an introduction to the Fundamentals of CHP Systems, Engineering
Issues, Benefits and Barriers to CHP’s broader utilisation, Micro and
Distributed Generation – Cogeneration and Trigeneration, Examples of
implementation
ACRONYMS
Combined Heat & Power (CHP)
Buildings Cooling, Heating & Power (BCHP)
CHP for Buildings (CHPB)
Integrated Energy Systems (IES)
Total Energy Systems (TES)
Trigeneration Systems (Trigen)
CHP for Industry
Cogeneration
COMBINED HEAT & POWER (CHP) - MICRO AND
DISTRIBUTED GENERATION AND TRIGENERATION
Micro Combined Heat and Power or MicroCHP
is an extension of the well established idea of COGENERATION
to the single/multi family home or small office building
Micro - CHP Systems Technologies
What is CHP - Cogeneration - HP Production
Why Consider CHP
What is Trigeneration
CHP Characteristics of Good Applications
CHP Barriers
CHP Managing Overview & Services
Combined Heat and Power Productioon
Exhaust
Gas
Natural Gas
Air
Kathalyst
Exhaust Gas
Heat Exchanger
< 120 °C
Lubricant Oil
90 °C
Peak Load
Boiler
Final Heat User
Electrical
79 °C
84 °C
.
82 °C
V = f(DP)
Grid
Engine Cooling
Waterr- / -Oil
Heat Exchanger
.
V = f(T)
70 °C
Thermostat
What is CHP
Combined Heat and Power
– Cooling, Heating & Power
– Total energy systems
– Cogeneration / trigeneration
– Energy recycling
It is an Integrated System that:
– Supplies electrical or mechanical power
– Uses thermal output for space or water heating, cooling,
dehumidification, or process heat
– Is located at or near user
– Can serve a single facility or district energy system
– Can range in size from a few kW to 100+MW
How CHP Saves Energy
Electrical efficiency
 e  Qe Q fuel
Heat efficiency
 heat  Qheat Q fuel
Overall efficiency
tot  (Qe  Qheat ) / Q fuel
(also called “Cogeneration efficiency
or “Total efficiency)
Power-to-Heat Ratio
  Qe / Qheat
Where is:
Qe
– Gross electrical output, kWe
Qheat – Usefull heat output, kWth
Qfuel – Fuel energy input (based on Net Caloric
Value (Lower Heating Value: LHV)), kWth
36  80

 0,58
200
30  55

 0,85
100
Separate Production of Electricy
and Heat
POWER PLANT Fuel 100 Electricity 36
BOILER Fuel 100 Heat 80
Total Efficiency: 0,58
Cogeneration
POWER and HEAT
Fuel 100
Electricity 30 and Heat 55
Total efficiency: 0,85
CHP System Sizes (Terminology)
TECHNOLOGIES
Micro CHP systems are currently based on
several different technologies
Internal combustion engines
Stirling engines
Steam engines
Microturbines
Fuel cells
Combined Heat and Power Productioon
Exhaust
Gas
Natural Gas
Air
Kathalyst
Exhaust Gas
Heat Exchanger
< 120 °C
Lubricant Oil
Peak Load
Boiler
90 °C
Final Heat User
Electrical
79 °C
84 °C
.
82 °C
V = f(DP)
Grid
Engine Cooling
Waterr- / -Oil
Heat Exchanger
.
V = f(T)
70 °C
Thermostat
QK
Condenser
Compressor
Expansion
Power
Evaporator
Q0
Vapour compression cooling mashine
Wapor Steam
Heat
From back
cooling
Condenser
Trigen
Block
Generator
dilute
solution
Concentrated
Wasser
Expans.
Valve
pump
Abwärme
Absorber
Evaporator
To back
cooling
Wasserdampf
Air Conditioninig
Plant
Absorptions refrigeration plant
Trigeneration Module
Exhaust
Gas
Natural Gas
Air
3-Waycatalyst
Exhaust GasHeat
Exchanger
Cooling
Engine
watercooling- / -oil
Heat Exchanger
TRIGENERATION
HeatStorage
Absorptionscooling plant
Power-Heat-Cool-Coupling
CoolEnergyStorage
Electricity
POWER – HEAT – COOL - COUPLING
el = 35 % 34 %
Gas
100 %
100 %
th = 55 %
53 %
Electricity
Heat
13% Losses
Absorption
Cooling Plant
38 %
Kälte
zref = 71 %
6 °C / 12 °C
Absorption Cooling „fueled“ by the Heat
Separated Production
Electricity
9%
Primary
energy
121 %
Compression
coolingmashine
el = 36 %
38% Cooling
eKKM = 4
77 %
34 % Eliectricity
Losses
Power-Heat-Cooling-Coupling
Primary
energy
100 %
el = 35 %
th = 55 %
13 %
Heating 53 %
Absorbtion
cooling
plant
38% Cooling
zAKA = 0,71
34 % Electricity
Losses
POWER – HEAT – COOL - COUPLING
Back
cooling
Supermarket/
Office building/Hospital
Natural Gas
Heating in Winter
Electrical
Grid
Safety cooling
Trigen
Block
Heat
Storage
Absorber
CoolStorage
Electricity
Power – Electr. Grid – Heat – Cooling - Coupling
Back
Cooling
Natural Gas
Supply
Oil for Natural Gas Supermarket/Office
Building/Hospital
Supply
heating
Electrical
Grid
Energy
Supply and
Saving
Safety
cooling
Trigen
Block
Boiler
Power – Electr. Grid – Heat – Cooling - Coupling
THE BUILT ENVIRONMENT
MAJOR CONSUMER OF HEAT AND
ELECTRICITY
The environmental damage caused by the use of energy
coupled with advances in technology has led to a change in the
view of the building as an energy system.
Technologies such as photovoltaic facades, fuel cells,
ducted wind turbines and cogeneration allow a building
to produce clean energy for own needs – heating/cooling/electr.
Raised best performance related issues, matching demand
and supplied heat and power, optimization (design &
control) of the interaction of the EG (DEG) with HVAC/technical
systems in transient conditions.
The answer to most of these questions requires some form of
integrated building design and systems simulation.
MODELLING AND SIMULATION OF
SMALLSCALE EMBEDDED GENERATION
SYSTEMS
Advances in heat and power production lead to a
revolution in buildings perception as an energy
system.
The addition of heat and power production increases
buildings complexity and new design issues must be
addressed:
– integration of DEG with traditional systems;
– optimal demand and supply matching;
– demand side management and its impact on environmental
performance;
– interaction of the DEG system with the local electricity
network, etc.
Small-scale CHP installation analysis
CHP contribution:
- 30% electrical load
- 23% heating load
CHP benefits (Feb-May 05):
- 7,000 kWh primary fuel
savings
- 1,450 kg CO2 savings
Optimisation:
- 2 units running
simultaneously
5.5 kW el, 12.5 kW th
Max 83oC water out
Sustainable Research
Building
Nottingham University
ELECTRICAL POWER
COOL
USEFUL HEAT
TRIGENERATION
STATE OF THE ART
Existing installations:
- medium to large-scale
- Prime movers: Internal Conmbustion engines and
turbines
- Cooling: absorption chillers
Challenges in small-scale applications
- Cooling technology?
- Costs?
- Fuel and emissions?
TESTING, SIMULATION AND ANALYSIS
OF A SMALL-SCALE TRIGENERATION
Designers need simulation tools to help answer
questions relating to building environmental performance.
For the development of integrated EG schemes,
building simulation tools must evolve to facilitate all
aspects of DEG systems modeling:
- EG components, electrical power flow, demand
and supply control algorithms, etc.
- To assess the interactions between an EG system
and all other components of a building, modeling,
must be undertaken in an integrated manner.
MODELING AND SIMULATION
Simulation – modeling tools
have evolved to assist in the design and assessment of
building performance, particularly in:
- low energy building design,
- modeling of active and passive solar systems,
- modeling natural ventilation systems
- daylighting and effects of saving technologies
- modeling of modern, building integrated heat and
power sources such as photovoltaics and fuel cells.
SUMMARY AND CONCLUSION
MICRO SCALE DEG AND TRIGENERATION
Evaluation of benefits of CHP installation
Optimisation:
Interaction CHP/Building’s heating system
Trigen Heat/Power/Cooling capacities ratios•
Outcomes: Trigen offers
Significant primary fuel savings
CO2 emissions reductions
However, payback period can be/very long! ?
Future work: Improve component efficiencies - COP
CHP FOR INDUSTRY - THE CONCEPT THE
IOWA ETHANOL INDUSTRY
Improved Reliability
Support Grid Infrastructure
Lower Energy Costs
– Defer Costly Grid Upgrades
Better Power Quality
– Price Stability
Lower Emissions (including CO2)
Facilitates Deployment of New
Conserve Natural Resources
Clean Energy Technologies
ResourcesResources
Enhances Competition
CHP FOR
HIGH ENERGY USERS
Example Ethanol Facility
–Thermal
»75–80% Energy Costs
are Natural Gas
- Steam Production
- Dryers»
» $10 Million/Year
–Electrical
»~ $2.5 Million/Year
»3.5 to 4.5 MWe Load => 30 to 40 Million kWh/Yea
–Process Can Use all the Thermal Produced
»Expect Between 4,300 and 5,300 lbs/hour per Installed MWe
CHP AT AN ETHANOL FACILITY?
Both Thermal and Electric Reliability Very Important
–Lose Batch
–Several Hours to Restart
Electric Reliability
–Grid Backs Up CHP System
–CHP System Backs up Grid
Thermal Reliability
–CHP System Provides Part of Thermal Load
–Boilers Sized to Provide All of Thermal Load
Reliability In Design
–Systems Need to be Designed to Do This!
CHP AT AN IDUSTRIAL FACILITY?
Long Hours (7/24/365)
Availability of Fuels Other than Natural Gas
–Coal
–Biofuels
–Waste Water or Land Fill Gas
Saves Energy
–Efficiencies Upwards of 85% because of
High Thermal Use and Value
Reduces Energy Costs
TYPICAL INDUSTRIAL CHP SYSTEM
RELIABLE CHP TECHNOLOGIES
Electric Generation Equipment
Gas Turbines and Engines, Reciprocating Engines
and Steam Turbines
RELIABLE CHP TECHNOLOGIES
Heat Recovery Systems
- Steam and Hot Water
- Exhaust Gases
Absorption Chillers
Desiccant Dehumidification
Northern Power supplied a hybrid solar PV / microturbine
standalone power system for a new PEMEX natural gas
production platform.
The Lankahuasa-1 platform, an innovative tripod design is the first
offshore site deployed as part of PEMEX’s strategic gas initiative
program, tapping the newly discovered gas reserves southeast of
Tampico in Mexico.
KEY FACTORS FOR CHP INDUSTRIAL
ATTRACTIVENESS
High Energy Use
Coincident Needs for Electrical and Thermal
Energy
Cost of Buying Electric Power from the Grid
Relative to the Cost of Fuel
Installed Cost Differential Between a
Conventional System and a CHP System
WHY THE OPPORTUNITIES FOR DEG
ARE IN GROWTH?
Aging Electric Transmission and Distribution Systems
– Difficult to Site New Lines
– Capacity Constrained
– Costly to Maintain
Rising Concerns Over
– Blackouts/Brownouts
– Power Supply Constraints
– Electricity Prices
MAIN IMPEDIMENTS TO CHP
High First Cost
Discourages Investment Despite Life Cycle Benefits
Assessing CHP Value (Beyond Energy Cost Reduction)
Hard to Identify, Quantify, and Allocate Among Parties
Stakeholder Apathy
Lack Lack of Incentive for Facility Managers and
Engineering Firms to Try Something Different
Too Few Case Studies
Inconsistent, Hard to Find, and Often Incomplete in
Financial Details
Permitting Process
Sometimes Long, Cumbersome, and Costly
Electric Utility Response / Interconnection
Often Times Ambivalent at Best, Hostile at Worse Inconsistent
Standards, Complex Process, Network Issues and
Unpredictable or High Costs
Natural Gas Prices / Volatility
Creates Uncertainty in Energy Costs
Utility Tariffs
Standby Charges and General Rate Design
Lack of Familiarity
With CHP Technologies, Concepts, and Environmental
Benefits
Electric Restructuring
Creates Uncertainty and a “Wait and See” Attitude
Ultimately this should lead to creating an environment
that enables DER to succeed.
DECENTTRALISED GENERATION
Central power station
Central power station
Photovoltaics
power plant
Transmission Network
Storage
Storage
Flow
Control
Storage
Storage
House
Distribution Network
Local CHP plant
Power
quality
device
Wind
power
plant
Factory
Commercial
building
Yesterday
Power
quality
device
House with domestic CHP
Tomorrow: distributed/ on-site generation
with fully integrated network management
CHP : cleaner, cheaper and competitive
DISTRIBUTED GENERATION
WITH HIGH PENETRATION OF
RENEWABLE ENERGY
SOURCES
Distributed Generation (DG) is growing in
popularity to meet urban, rural, and diverse
customer loads. Integrating the various
Distributed Generation technologies into a
power system in efforts to improve reliability
vary for each application.
Distributed generation a new trend in the generation of heat and
electrical power, or Distributed Energy Resources (DER)
concept permits "consumers" who are generating heat or electricity for
their own needs (hydrogen station and microgeneration) to send
surplus electrical power back into the power-grid so known as net
metering - or share excess heat via a distributed heating grid. Distributed
generation systems with (CHP) systems can be very efficient, using up
to 90% of the potential energy in the fuel they consume. CHP can
also save a lot of money and fuel.
Estimates are that CHP has the potential to reduce the energy usage of
the USA by up to 40%.
A cluster of distributed generation installations is view as a Virtual
power plant.
Even if the term "distributed generation" is quite well established, terms
like distributed power, distributed energy, distributed energy
resources, embedded generation, decentralized power, dispersed
generation, and onsite generation can also be found in the literature.
Although some of those terms may be used with a different meaning,
typically they exactly refer to distributed generation.
DISTRIBUTED GENERATION OFFICE
BUILDINGS
DEG energy resources are wind, solar, biomass, fuel cells, gas
microturbines, hydrogen, combined heat and power (CHP), and
hybrid power systems.
DEG technologies maturity coincided with energy
deregulation, creating a fertile environment for DEG projects
General benefits of building’s DEG applications:
Overall load reduction
Energy independence
Standby/backup power
Peak shaving
Net energy sales
Combined heat and power
Grid support
Premium power for sensitive applications
Central power loses 73 percent of total input energy before it
reaches the consumer (65 percent in heat loss at the generator plus eight
percent lost in transmission).
DG electricity travels a shorter distance, so are losses during
transmission. Furthermore, these smaller generators tend to be more
efficient as the new technologies and site-appropriate equipment
systems.
DEG can be more efficient than central power,
but it must not be environmentally clean.
DEG does encompass renewable
energy systems that reduce greenhouse gas
emissions, but it also includes generators that
burn fossil fuels, particularly natural gas and
diesel.
DEG environmental impact depend on the
fuel kind.
Solar turbine and
5.2 MW
cogeneration plant
Arden Realty USA
SOME UTILITY BENEFITS OF
USING DEG
Dispatchable peak demand reduction
Maximum use of standby capacity through safe
parallel operation with the utility grid
Cost-effective solution consistent with least cost
planning emphasis
Improved system load factor
Enhanced voltage stability and avoided line losses
during heavy-load conditions
Improved customer relations
CUSTOMER BENEFITS AND FORCES OF DEG
Bill reduction
Reliability improvement
Power Quality (PQ) improvement
Customer partnerships
Customer Forces
Restructuring and evolving regulation drive
customers to be more proactive and informed about
energy purchases and investments.
Increasing need for differentiated energy services,
– reliability
– quality
Cogeneration/thermal - “green” energy
TECHNOLOGY FORCES
Smaller, More Modular Generation
Shifting Economies of Scale equipment
manufacturing versus central generation
Improving Efficiencies of Smaller
Technologies
More Flexible “Optimizable” Solutions
Many Improvements Driven by Significant
Technology Push in Automotive Sector
BARRIERS
Technical - addressable with traditional technology
based RD&D
– DR technologies
– technical evaluation techniques & tools
Institutional - requires covering new, mostly
nontechnical ground
– business/management theories
– new regulatory structures
– new standards
Fundamentals of Combined Heat and Power Systems
Introduction to DG and CHP; Prime Mover Technologies;
Thermal Loads for CHP;
Generators and Electrical and Utility Interconnections;
Heat Recovery Technologies;
Commercial and Industrial Applications;
Application Opportunities;
Financial Evaluation;
Design Project Management
Engineering Issues in Combined Heat and Power Systems
Prime Mover Cycles, Efficiencies, and Thermodynamics;
Thermal Technologies and Interconnection Design-Commercial;
Thermal Technologies and Interconnection Design-Industrial;
Economic Analysis Techniques;
Economic Analysis Software Training;
Case Study Exercises;
THE INTERNATIONAL
JOURNAL OF DISTRIBUTED
ENERGY RESOURCES is a
scholarly peer-reviewed archival
Journal.
It publishes experimental,
theoretical and applied results in
both science and engineering for
distributed energy resources in
electrical grids.
A thorough peer-review of each
paper is performed by at least two
independent experts for the special
topics addressed.
Contact and Call for
Papers:
ISET e.V.
Editorial Office
info@der-journal.org
http://www.derjournal.org/