Although not strictly a renewable technology, CHP is certainly a low carbon technology. CHP simply refers to the simultaneous production and use of electricity and heat.
CHP systems come in a number of forms such as; stirling engines, spark ignition engines, gas turbines, steam turbines and fuel cells, with electrical outputs ranging from a kilowatt (kW) to multiples of megawatts (MW).
The key to successfully implementing a CHP scheme is to ensure that both generated electricity and heat can be usefully employed on the site.
CHP systems use natural gas in either an engine or turbine, or via a reformer to produce hydrogen for use in a fuel cell. CHP systems then produce electricity, which displaces grid imported electricity, reducing electricity bills and hot water or steam, which displaces hot water from and therefore gas burn in the boilers.
A 10kW CHP engine can produce annual emission savings of up to 26 tonnes of CO2, and annual cost savings of over £4,500, based on a gas cost of 3.5p/kWh and an electricity cost of 10p/kWh, and an assumed boiler efficiency of 85%. For an installation cost of £30,000, simple payback is in the region of 6 years. However, when the new feed in tariff comes into force, CHP up to 50kW will qualify, and this will lead to further reductions in paybacks.
CHP is a simple way to reduce emissions and costs, and operates alongside existing boiler plant, making installation simple. It is a transition technology to the low carbon environment and provides clients with an opportunity to move towards greener generation.