Status of Pressurized SOFC/Gas Turbine Power System Development at Siemens Westinghouse

Abstract

Pressurized solid oxide fuel cell (PSOFC)/micro gas turbine generator (MTG) hybrid power systems have the potential to generate electric power at high efficiency [circa 60% (net AC/LHV)] at multi-hundred kWe and multi-MWe capacities. Thus, good fuel economy and low CO2 emissions are positive system attributes, as are low NOx and SOx emissions due to the propensity of the SOFC for low NOx generation, the need for no firing of the gas turbine combustor during normal hybrid system power operations, and the use of desulfurized fuel. Exhaust temperatures are sufficiently high to enable the recovery of heat for steam/hot-water production, and system energy efficiencies of at least 80% are feasible. Work is ongoing at Siemens Westinghouse on three PSOFC/MTG power systems. Two, with 220 kWe and 300 kWe capacities, are proof-of-concept demonstration units. The 220 kWe PSOFC/MTG power system is in test at the National Fuel Cell Research Center, University of California-Irvine, and the 300 kWe system, which is currently being designed, will be demonstrated in two tests to be performed in Europe. The status of work on the 220 kWe and 300 kWe power systems is reviewed. The third system is to have capacity of at least 500 kWe. This system, which will be demonstrated also, is viewed as a prototype commercial product. The 500 kWe-class PSOFC/MTG concept is described and performance estimates are presented.