Combined heat and power technologies (CHP) offer a highly efficient way to use fuels in the energy sector. They can therefore help to decrease CO₂-emissions and to save resources

Due to the global climate change and in accordance with the declared objectives of the climate agreement, which was adopted on the UN Climate Change Conference in Paris in 2015, the European countries have to reduce their CO₂ emissions. Numerous technological measures are necessary, which are topically in the stage of realisation or development. Central measures are the development of the renewable energy systems as well as the efficiency increase of both, the energy generation and the use of energy. Other approaches are the CO₂ capture and storage and its utilization in different chemical and thermodynamic processes.

Until now the focus of all these measures has been the electricity generation sector, which corre-sponds to less than 30 % of the total CO₂ emissions of the European Union. However, the transport and heat generation sectors have to be involved in this process to achieve a maximum emission reduction.

One option to increase the energy efficiency of the heat generation sector is the use of combined heat and power plants. The potential and the current state of this technology were analysed and assessed by the Scientific Advisory Board of the VGB on basis of the study “Long term prospects of CHP” [Kakaras et al.] of the National Technical University of Athens, Greece.

This study acknowledges the merit of combined heat and power systems as a means for efficient generation of electricity and heat because of the higher utilization of the fuel energy, compared to that occurring in separate generation. Thus, CHP is a superior technical option given that there is a strong heat demand as e.g. in industrial applications. Regarding future applications CHP plants may have more variable power-to-heat ratios due to market conditions to support flexible backup energy for fluctuating RES.

An important but may be limiting aspect for the application of CHP plants is the reduction of the total heat demand caused by measures like improved house insulation or the expansion of the renewable energy sources that are directly used in the heat market or deliver electricity surpluses that are applied for heat generation. As a result the market potential for combined heat and power systems will change in different ways in the future. CHP plants can be designed in a way to flexibly adapt to the future developments in the different markets. To sum up, the case specific local boundary conditions of applications need to be carefully considered in order to properly evaluate the suitability and profitability of a combined heat and power system. The decision should be made on an economic basis. CHP and other technical options should be considered without preference for individual options (i.e. equal conditions of competition for all concepts, including CHP and installations with pure electricity or heat generation). However, these framework conditions are currently not being met in some countries due to the presence of different support schemes. Meanwhile, it is very important to investigate the actual, realistic CHP potential in different Member States.