Combined Heat and Power

Combined Heat and Power (CHP or cogeneration) is a device that simultaneously generates both electricity and useful heat. Different types of engines can be used to achieve CHP and can give high efficiency using natural gas as a fuel. The internal combustion engine in a highly sophisticated car engine is an example as is a well proven technology however; CHP products based on ICE can be noisy and is limited on the type of fuels used. Recently stirling engines have been developed to produce domestic combined heat and power appliances. These appliances will ultimately replace the domestic boiler for a single home in the near future i.e. within the next few years.

Another 'engine' which is being developed is the fuel cell. The fuel cell is not strictly an engine but uses a chemical reaction to produce heat and electricity at a very high efficiency. Domestic appliances based on this technology will to be available until 2012 or beyond.

CHP systems tend to produce more heat than electricity which is a likely requirement for the home and the demand for both will fluctuate depending on the seasons. As far as the electricity output is concerned, a CHP system supplies only part of the required load and is normally dependent on the electric grid supply being available. Potentially, the advantages are significantly reduced costs and carbon emissions.