Power generation efficiency of photovoltaics and a SOFC-PEFC combined micro-grid with time shift utilization of the SOFC exhaust heat

The operation plan of a solid-oxide fuel cell (SOFC) and a proton -exchange membrane fuel cell (PEFC) with time shift utilization of the SOFC exhaust heat is developed. The proposed system in this paper consists of a SOFC-PEFC combined system and a photovoltaic system as the energy supply to a micro grid of 30 residences in Sapporo, Japan. The operation plan of the system has three cases: without solar power, with 50% and with 100% of solar output power. Furthermore, three types of system operation of using the SOFC independent operation, PEFC independent operation and SOFC-PEFC combined system are used to supply the demand side. A comparative study between the types of system operation is presented. The power generation efficiency is investigated for different load patterns: average load pattern, compressed load pattern and extended load pattern. This paper reported that the power generation efficiencies of the proposed system at different load patterns are 27% to 48%.