Challenges and Opportunities for Fuel Cells in Stationary Power Generation

Abstract

Fuel cell power systems are considered attractive for a wide rangeof stationary power generation applications including residential, com-mercial, and industrial distributed generation, as well as large utilitypower plants. The current interest in fuel cell systems stems from theirpotential for high efficiency (lower heating value (LHV) efficiencies of35-70 percent, depending on technology and system capacity). In addi-tion, fuel-cell technology has demonstrated very low (truly negligible)emission levels and has noise characteristics similar to air-conditioningsystems (i.e., mostly air-moving equipment). Routine maintenance offuel cells has the potential for being minimal even in low-capacity sys-tems because there are no heavily loaded mechanical subsystems re-quired (unless compressors are required for pressurized operation).Four primary fuel cell technologies are being developed for station-ary applications.• Polymer Electrolyte Membrane Fuel Cell (PEMFC);• Phosphoric Acid Fuel Cell (PAFC);• Molten Carbonate Fuel Cell (MCFC); and• Solid Oxide Fuel Cell (SOFC).The past two decades have seen impressive advancements in thescience and technology of these fuel-cell power systems. Excellent dis-cussions of the science and technology of all the major types of fuel cells,recent developments and remaining technical challenges can be found in references [1-2].We address the end-user economics of fuel cell systems for station-ary applications using planar, 5-kW anode-supported SOFC technologyas an example. Planar SOFC is receiving a great deal of attention as partof both government—the Solid State Energy Conversion Alliance (SECA)program—and industry initiatives. The increasing interest in planarSOFC is the result, in large part, to technology developments (anode-supported thin-film electrolyte designs) in which the total ohmic resis-tance of the stack is significantly reduced allowing for lower-temperatureoperation (650 °C-800°C rather than 1000 °C) than was previously thecase.We also discuss the important cost elements that determine the costof electricity from fuel cell power systems including factory, material,installation, and operating and maintenance (O&M) costs. We assess theimpact of success in ongoing R&D programs on the cost of electricity.