Much hope is held for solid oxide fuel cells (SOFC) as highly efficient and clean power-generating devices. MHI is advancing the development of SOFC. On this occasion, as part of research commissioned by the New Energy and Industrial Technology Development Organization (NEDO), MHI conducted a trial operation of a pressurized SOFC system at the MHI Nagasaki Shipyard & Machinery Works, being successful in generating 35kW, which is the maximum output generated with SOFC in Japan.

SOFC generate electric power directly from city gas, using ceramic (Note 1) fuel cells operating under high temperatures of approximately 900 degrees Celsius (Note 2). By using a combined cycle that drives gas turbine using the high-temperature exhaust heat from SOFC, it is possible to configure a 60-70% high-efficiency power generation system.

Based on these results, from fiscal 2006, we plan to test operations of SOFC combined cycle power generation systems that link SOFC with MHI micro gas turbine.

Note 1: Zirconia type ceramics are used. Zirconia ceramics have a property of conducting oxygen ions at high temperatures, and are used in oxygen meters and in CO meters for vehicles.

Note 2: Polymer electrolyte fuel cells (PEFC), which operate at low temperatures, are attracting attention as cogeneration systems for use in vehicles and in homes. Since PEFC use only hydrogen fuel, they are used once the city gas fuel has been converted into hydrogen by way of a reformer.
With SOFC, since they can use city gas directly, they have a 20 percent higher (relative value) power generation efficiency than the low-temperature PEFC.
Furthermore, coal and other fuels used in thermal power generation will open the way for SOFC to be used by gasifying. It is hoped that this will contribute to reductions in emissions of CO2 by promoting higher efficiencies in thermal power generation.