Abstract: The present invention uses an internal combustion engine operated at an air/fuel ratio richer than stoichiometric as a partial oxidation reformer in fuel cell power generation systems. Commonly available liquid or gaseous hydrocarbon or alcohol fuels, including “logistic” fuel in military applications, are converted to a product gas mixture containing hydrogen, carbon monoxide, and traces of light hydrocarbons. The product gas may be used directly or with minimum processing by high temperature fuel cells, or processed further for use in low temperature fuel cells. Advantages include high efficiency, adaptability to a variety of fuels, and quick system startup with immediate shaft power availability.