A new concept for small-scale combined heat and power

Effective small-scale CHP plants that give a better level of profitability and a higher level of electricity efficiency. This is the ambition of a new research project that is being supported by the Swedish Energy Agency.

The goal is to increase the biofuel-based electricity production by the development of small-scale combined heat and power. The technique will be mostly applied in smaller district heating systems and in new plants that are integrated with industry.

The Energy Agency has made an assessment that there is sufficient potential to increase electricity production by at least a further 3 TWh within the combined heat and power sector. In order for it to be possible to achieve this potential, a technical development of the combined heat and power process is required with a focus on small-scale application. Continued research and development is also needed in order to achieve higher steam data – the pressure and temperature of the steam that is to drive the steam turbine, in order for this to be possible.

A consortium led by the company BioSteam AB is in the process of developing a new system solution for small-scale combined heat and power. The investment is partly financed by the Swedish Energy Agency and the aim is develop a technical system solution that permits a higher electricity extraction than is otherwise at present normal on the market within small-scale CHP for the electricity production range of 2 – 4 MW.

"In the past, we have started with a large combined heat and power plant and then scaled it down into a smaller facility, but then with relatively low steam data. This has led to facilities with a low efficiency level, and thus a high specific investment cost," says Lars Atterhem at BioSteam.

Once the analysis phase has been completed, the technical solution will be transformed into a feasibility study for a new combined heat and power plant at Martinssons Såg in Västerbotten. The new plant will be designed to achieve a higher level of electricity extraction than is currently possible through further development of the technique and rational construction in order to keep investment costs down.