Combined Heat and Power

Solution advantages

  • Allowing the supply of both heat and electricity from a single energy source
  • Reducing carbon emissions by generating electricity at the point of use – avoiding the system losses associated with central power production
  • Allows gas to be used more efficiently
  • Generating economic savings by reducing imported electricity and selling surplus electricity back to the grid
  • Enhancing security of supply by reducing reliance on centralised power production

More than just a heating system

In heating systems, the primary energy source is converted into heat. In contrast to this, combined heat and power generation (CHP) produces both heat and electricity in the one independent appliance. By using the primary energy source economically in this way, cogeneration of heat and electricity not only contributes to an overall reduction in energy consumption, but it also contributes directly to the protection of the environment.

The technology is nowadays also available for small-scale production of heat and power (micro-CHP and mini-CHP) for commercial and public buildings, apartments and individual houses. Small scale CHP generates electricity at the time of day and time of year when heat demand is at its greatest, thereby coinciding with the times when demand on the electricity grid is at its peak.

Europe  is a global leader  in micro-CHP engine and product technology, with innovation and  manufacturing centres in Germany, the Netherlands and the UK.

Current state of technology

As far as the basic technology is concerned, a distinction is to be drawn between internal and external combustion engines (Otto engines and Stirling engines), steam expansion engines and fuel cells. A range of micro-CHP appliances are commercially available in Europe, mainly internal combustion engines and Stirling engines. Fuel cell technology is currently under demonstration phase and will be commercialised in the very near future.

The process heat released by the motor is used for space heating and for domestic hot water. The electricity produced is used as required and any excess power fed into the national grid. Decentralised cogeneration of heat and power is a highly efficient way of supplying both space heating and electricity.

The fuel used, such as natural gas or heating oil, drives a combustion engine with a power generator coupled to it, thus producing electricity. In future, it is entirely conceivable that renewable energy sources such as biogas, vegetable oil, wood pellets and indeed bio-ethanol will be able to be used.

The right solution for every requirement

Consumers have a choice of different CHP solutions from outputs of just a few kW to several hundred MW. Micro-CHP units with power outputs of up to 5 kWel are used for detached and semi-detached houses, while mini-CHP units of up to 50 kWel have been developed for small apartment blocks and business premises. No district heating network is required for these smaller CHP units. Industrial premises and also larger housing estates, hospitals and schools use larger CHP units or block cogeneration plants with outputs starting at around 50 kWel. In these applications, CHP systems can supply up to 100 % of the heat and 80 % of a building’s power requirements; moreover, CO2 emissions can be reduced by up to 40 %. In future a large number of block cogeneration plants working together as a “virtual power station” will help smooth out voltage fluctuations in the public power supply.


Wall-hung micro-CHP unit
Wall-hung micro-CHP unit
Floor-standing micro-CHP unit
Floor-standing micro-CHP unit