Like molten carbonate fuel cells, solid oxide cells require high operating temperatures, and their most common application is in large, stationary power plants. The high temperatures open the opportunity for "cogeneration"–using waste heat to generate steam for space heating, industrial processing, or in a steam turbine to make more electricity.
Solid oxide fuel cells, like most other types, produce little pollution. Although they require inverters to change their direct current to alternating current, they can be manufactured in relatively small, modular units. The compact size and cleanliness of SOFCs make them especially attractive for urban settings like Tokyo, where 25 kw units are already on line.