If a power station is near to a market that requires heating (such as a housing estate, school or hospital) it seems nonsensical to burn waste (or indeed any fuel) to create heat which, in turn, has to go through a conversion process to generate electricity, which is only used to make heat again. Each conversion process contains energy losses and so is inefficient. Much better then to make use of the first conversion and distribute this heat in the form of piped hot water or steam to communities or other demand such as industry, offices or a hospital. Also, a television set requires a high grade energy (in this case electricity). Warming a room requires low temperature heat - a much lower grade of energy. It is therefore inefficient to heat a room with electricity if there is an alternative - using heat direct for this purpose conserves energy by eliminating the losses associated with energy conversion from heat to electricity and back once more to heat.

When generating electricity in any situation it will be found that much of the primary energy will be lost and not used as it escapes in the form of heat in stack emissions, or in cooling water. In the case of fossil fuel power stations two thirds of the energy is discarded in this way. To boost efficiency this hot water can be used for community heating schemes, while the electricity still goes to power these people's household appliances. The harnessing of this latent energy is the approach utilised by a combined heat and power (CHP) plant.

Ideally if demand is high enough then all the energy generated would be exported as heat. On any moderately large scale this is unlikely and also the demand will fluctuate which would require sporadic plant operation. Generation of electricity can utilise that amount of total energy never required as heat, and within designed operating conditions can increase or decrease according to daily demand.

This process because of the overall increased efficiency has the environmental bonus of increasing the amount of useful energy per unit of CO2 emitted to the atmosphere. Generating power by CHP, therefore, helps the UK towards meeting its international commitments to reduce carbon dioxide emissions

There are many fossil fuel CHP plants operating in the UK. Several Waste-to-Energy plants have taken to the process, also. The Coventry plant exports process heat to a local company. 'Sheffield Heat And Power' takes in waste and exports hot water or steam to commercial, residential and public buildings in the city centre. Nottingham's Eastcroft incinerator supplies steam for community heating and also generates electricity. (ref. www.efw.org.uk).