Patent ID: 7250231

Claim:
An auxiliary fuel cell system configured to backup a primary power source adapted to supply power to an energy-consuming system, the primary power source being in electrical communication with the energy-consuming system via at least a first power linkage, the first power linkage being configured to be enabled and disabled regardless of whether the primary power source is producing electric current, the auxiliary fuel cell system comprising: a fuel source; an oxidant source; a fuel cell stack configured to conditionally produce an electric current from fuel received from the fuel source and oxidant received from the oxidant source according to the operating state of the primary power source, wherein the fuel cell stack produces electric current when the primary power source is in an interrupted operating state, and the fuel cell stack does not produce electric current when the primary power source is in a power delivery operating state, wherein the primary power source includes at least one of a utility grid, a wind-powered energy source, a solar-powered energy source, a water-powered energy source, and a nuclear-powered energy source, wherein the auxiliary fuel cell system is in electrical communication with the energy-consuming system via at least a second power linkage, the second power linkage being configured to be enabled and disabled regardless of whether the auxiliary fuel cell system is producing electric current; and a source-selection subsystem that selectively enables and disables at least the first and second power linkages to selectively regulate, based at least in part upon determination of the operating state of the primary power source, which of the auxiliary fuel cell system and the primary power source is currently configured to provide power to satisfy an applied load from the energy-consuming system, wherein the source-selection subsystem is configured to implement a break-then-make connection to prevent backfeed between the primary power source and the auxiliary fuel cell system.