Factsheet: Combined Heat and Power (CHP)
What is Combined Heat & Power?
Combined Heat and Power (CHP) is the simultaneous generation of usable heat and power (usually electricity) in a single process. CHP can achieve energy efficiency levels of 80% whereas conventional power stations, which reject heat via cooling towers, have efficiency levels of between 35% (coal) and 50% (gas).
How does it work?
CHP systems can be employed over a wide range of sizes, applications, fuels and technologies. In its simplest form, it employs a gas turbine, an engine or a steam turbine to drive an alternator, and the resulting electricity can be used either wholly or partially on-site. The heat produced during power generation is recovered, usually in a heat recovery boiler and can be used to raise steam for a number of industrial processes, to provide hot water for space heating, CHP systems are found in:
- Large industrial sites which use heat e.g. in the chemicals, food and paper sectors,
- Swimming pools, within leisure centres and hotels,
- Hospitals and Universities
- District Heating, providing heating to a group of different buildings.
What are the advantages of CHP?
- CHP is a highly efficient way to use both fossil and renewable fuels and can therefore make a significant contribution to the UK’s sustainable energy goals, bringing environmental, economic, social and energy security benefits.
- Because CHP systems make extensive use of the heat produced during the electricity generation process, they can achieve overall efficiencies in excess of 70% at the point of use. In contrast, the efficiency of conventional coal-fired and gas-fired power stations, which discard this heat, is typically around 38% and 48% respectively, at the power station. Efficiency at the point of use is lower still because of the losses that occur during transmission and distribution.
- In contrast, CHP is a form of a decentralised energy technology. CHP systems are typically installed onsite, supplying customers with heat and power directly at the point of use, therefore helping avoid the significant losses (which occur in transmitting electricity from large centralised plant to customer
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