SOFC technology has been developed for a broad spectrum of power generation applications. SOFC systems that have been considered ranges from portable devices (e.g., 500-W battery chargers), small power systems (e.g., 5-kW residential power or automobile auxiliary power units) to distributed generation power plants (e.g., 100–500 kW systems). SOFCs can also be integrated with a gas turbine to form large (several hundred kW to multi-MW) pressurized hybrid systems. The SOFC is the only type of fuel cell that has the potential for such a wide range of applications. Some examples of SOFC power system concepts are discussed below.