Natural gas reformed fuel cell power generation systems-a comparison of three system efficiencies

Net plant efficiencies of fuel cell power plants, operated with natural gas fuel, are analyzed on the basis of expected fuel cell performance. A comparison of net plant efficiencies of three types of fuel cell power generation systems is discussed. They are a phosphoric acid fuel cell (PAFC) system, a molten carbonate fuel cell (MCFC) system, and a solid oxide fuel cell (SOFC) system. The plant output is selected as 5 MW, corresponding to the expected largest capacity of natural gas reforming unit that can be transported by trailer. Each system is operated at an elevated pressure and consists of a natural gas reformer, a fuel cell unit, a power recovery gas turbine, and various heat recovery units. Since the analysis is aimed at net plant efficiencies around the year 2000, prospective performance is estimated from current performance data. Calculated system efficiencies were 42.7% for the PAFC, 51.2% for the MCFC, and 47.8%-49.7% for the SOFC