Transcript Co- and Poly- generation - Stefan.Schleicher(a)wifo

Co- and Poly- generation
Martin Hannemann
Andi Prah
Nuri Feichtinger
Paul Polterauer
The Co-generation Concept
• Co-generation is often referred to as a
technology.
▫ Actually co-generation is a principle that describes
how energy, which is produced as a natural biproduct of the electricity production process, is
captured and turned into useful heat.
• This process is also known under the shortcut
“CHP”, which means Combined Heat and Power.
Examples for CHP Plants
• Co-generation is applicable to all situations
where electricity is produced by thermal
combustion
• Co-generation systems are a modern way to
reach very high energy efficiency
▫ maximize fuel savings and avoid CO2 emissions.
• Most common types of CHPs are:
▫ Steam and Gas turbines
• Fast evolving technology
▫ Fuel Cells, Combustion Engines
Efficiency of Co- generation
• Backpressure steam turbine units are characterized
by high thermal efficiencies up to 90% and a
moderate electricity generation efficiency of 15% to
25%.
• Gas turbine heat recovery units show a thermal
efficiency of 75% - 80%. In case post-firing is
applied, thermal efficiency reaches close to 100%.
• Thermal efficiency of combined gas/steam cycle
systems reaches and sometimes exceeds 50%.
Scale of Co- generation
• Decentralization
▫ Mirco CHP
 usually less than 5 kWe in a house or small business
 electricity can be used within the home or business
or, sold back into the electric power grid
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A high overall energy conversion efficiency
Low maintenance requirements
Very low noise and vibration levels
Very low emissions of NOx, COx, SOx and
particulates.
• Centralization
▫ Disctrict Heating
 It centralizes the source of heat and electricity into a
single source
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+ lower investment costs
+ higher efficiency
+ lower operation and maintenance cost
+ higher reliability
+ more design flexibility
+ less energy is wasted
+ more space for home owners
Economic Aspects
• The majority of early adoptions of decentralized
energy technology were not good investments
under reasonable assumptions.
• There is a minimum treshhold for a positive
NPV on investment of about 160kWe
• Bigger scale plants yield a better profit ratio
Environmental Aspects
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environmental benefits by making use of
waste heat and waste products
Air pollution is a concern any time fossil fuels or
biomass are burned
New cogeneration plants often have to meet
higher environmental standards
High initial cost of cogeneration facilities
located in urban areas
Decentralized CHP units eliminate the energy loss
of a distribution system
Some CoGen systems do not capture as much waste
heat as others or cant make use of it due to their
location
Polygeneration
• Polygeneration describes an integrated process
which has three or more outputs
Classification of polygeneration
Trigeneration
• most popular form of polygeneration
• combine heat, cooling and power
• find application wherever the demand for heat, cold
and power occurs
▫ Comercial
▫ Office
▫ Hospital…
Efficiency of Trigeneration
• The main advantage is the efficient usage of fuel.
• This leads to saving fuels and money and also less
greengas will be produced.
• A reduction of fuel consumption will raise the
energy security of countries.
• Trigeneration systems support the usage of local
energy sources like biomass, biogas, or biofuels.
Economy
• The profitability depends on various factors and
certain conditions.
• Austria supports CHP biomass plants connected
to local heating networks. (15% to 35% of the
investment cost)
• In the United Kingdom there is a VAT discount
exist from 17.5% to 5% for micro CHP
installations.
• The investments are very sensitive for fuel unit
cost, and fuel prices are very variable.
Perspectives
• E.g. The potential of trigeneration technology
application in the food industry in Europe was
evaluated at approximately 16 TWhe per year.
• The most significant barriers of using the
potential of trigeneration systems are:
▫ a product of market conditions
▫ mainly unfavorable electricity and gas prices
▫ uncertainty over future market conditions
• These barriers need to be removed.
• In order to stimulate the market there is also the
task of technology development, the
trigeneration needs to be more reliable, efficient
and flexible.