Co- and Poly- generationMartin HannemannAndi PrahNuri FeichtingerPaul 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 bi-product 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▫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 + 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 • + 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.