Improving energy efficiency in small-scale biogas-powered solid oxide fuel cell systems by co2 removal and bidirectional operation

Electricity from biogas plays an important role in a fossil-free energy system since it provides base load power. However, the conversion process is usually based on gas engines with comparatively low electrical efficiencies. We developed a new CHP system for the conversion of biogas to electricity with a net efficiency exceeding 80 % by use of highly efficient solid oxide fuel cells (SOFC). In addition, the operation mode of the system can be reversed to serve as a power-to-gas facility for energy storage that provides a high reserve potential for the electrical grid. Within an ongoing validation project, we want to build and prove the performance of a fully functional small-scale 10 kWel demonstration plant in a 3-month field test with raw biogas.