• Solid oxide fuel cells (SOFC) have been proposed as an alternative energy technology for use in large stationary power applications (1 to 10MWof electrical power). These devices have an ion conducting ceramic material (such as yttria-stabilized zirconia) as the membrane that separates the anode from the cathode, and typically operate at 500–1000°C. There are two advantages to operating fuel cells at such high temperatures: They can be powered directly by fuels besides hydrogen, including carbon monoxide (which poisons the platinum catalyst in low-temperature fuel cells) and hydrocarbons, and the heat produced by fuel cell inefficiencies can be recovered and used elsewhere in the plant. In the SOFC shown in the following figure, a mixture containing 75 mole% hydrogen and the balance carbon monoxide