Maximize energy efficiency during energy conversion. Cogeneration (also combined heat and power, CHP) is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat. See 1.6.4 biomass energy and 3.2.1 solid waste treatment.
By-product heat, at moderate temperatures, can also be used for cooling, using absorption chillers. A plant producing electricity, heat and cold is sometimes called tri-generation or more generally, poly-generation plant.
Conventional power plants emit the heat created as a by-product of electricity generation into the environment, i.e. through cooling towers. CHP captures the by-product heat for domestic or industrial heating purposes either very close to the plant, or, as demonstrated in Scandinavia and Eastern Europe, for distribution through pipes to heat local housing.
Cost savings due to increased efficiency of up to 70%, compared with 40% for conventional plants.
By capturing the excess heat, CHP uses heat that would be wasted in a conventional power plant. Less fuel is consumed to produce the same amount of useful energy. Also, less pollution is produced for a given economic benefit.
CHP is most efficient when the heat can be used on site or very close to it. Overall efficiency is reduced when the heat must be transported over longer distances. Cogeneration plants are commonly found in district heating systems of big towns, hospitals, prisons, oil refineries, paper mills, wastewater treatment plants, thermal enhanced oil recovery wells and industrial plants with large heating needs.
1.7.2 District Energy Systems
1.7.4 Energy Recovery
3.2.0 solid waste treatment