Forms of power generation using combustion can generally be made more efficient if the surplus heat is captured and used too. This is called Combined Heat and Power (CHP).
In conventional power generation the large amount of heat produced as a by-product is lost. Combined Heat and Power technology puts this heat to use, recycling it for use in community heating or for industrial purposes. This makes CHP a much more fuel efficient method of power generation, increasing overall efficiency of fuel use to more than 75% compared with the 50% achieved by conventional power generation.
A variety of fuels can be used to power a CHP generator, as well as fossil fuels these include renewable sources such as Biomass, Geothermal and Solar Energy.
A CHP plant consists of one or more prime movers, such as a reciprocating engine, gas turbine or steam turbine which drives an electrical generator. The steam or hot water generated is then used rather than wasted.
CHP plants are generally smaller than electricity plants and are usually attached to a site that consumes all or most of the heat and power it produces.
High capital and maintenance costs mean CHP is more often used by the industrial, commercial or public sector rather than individual domestic users. It is popular with those requiring large amounts of heat, such as hospitals and leisure centers. As the plants generally supply electricity locally they also avoid transmission and distribution losses associated with conventional electricity supplies.
The increase in fuel efficiency means Combined Heat and Power is playing an increasingly important role in reducing carbon dioxide emissions, achieving reductions of as much as 50%.
Converting to Combined Heat and Power also lowers emissions of sulphur dioxide and nitrogen oxides, reducing acid rain.