Cogeneration (CHP) is designed primarily to service the heating requirements of a building. Therefore cogeneration takes over the base load of heat demand. Leaving aside one-and two-family houses, the annual number of hours of CHP plants is 3,000 to 8,000. For the economy, the type of usage of electricity is important. The current can be used in the building, the achievable rate of return is usually higher than if it is fed into the power of the general supply needs. Exception to this is the use of biomass fuels such as vegetable oil and biogas. In most cases an allowance under the Renewable Energy Act (EEG) is paid, which provides a higher energy output. On the other hand, in these co-generation plants the cost of fuel is situated higher than with use of natural gas and fuel oil.
Here are some application fields and the likely to be achieved annual returns of the listed by CHP plants. The returns can be realized due to the energy cost reduction for heat and power the building. The reported profit shall not be achieved if within the course of investment projects, co-generation plants are being built. In these cases an investment provider would also be earning. This significantly reduces potential profits. Yields depending on the case of usage can be estimated as follows:
One-and two-family houses
One-and two-family houses are suitable for the use of cogeneration. Especially due to the fact that in recent months new technologies such as Stirling engines and smaller internal combustion engines have come on the market, also the low demands of one-and two-family houses are covered well by CHP plants. The cost of such micro-CHP systems are very high, however, in relation to their performance. Heat demand of buildings are relatively low in the summer and usually only hot water is needed, the potential returns are relatively low due to energy savings. About two years ago, there was a mini-CHP climate incentive program (see our information pages) which included an investment subsidy for micro CHP. Unfortunately this program ran out about a year ago.
Especially in the smallest capacity range, however, a government investment promotion would be extremely important, since investment in relation to potential savings has a very high priority. In the Netherlands, for example, there are still investment grants for micro-CHP systems of up to € 4,000. With respect to the use of micro-and mini-CHP units in existing buildings, we recommend you investigate the „Heating cost comparison calculator“ of the German city of Dusseldorf which was developed by CHP Consult.
One / two family houses achieve a return of 6 – 12%. Particularly good projects can easily generate better returns. However, there are also many utilities and objects which generate lower returns and this for different reasons.