Fuel cells are clean, fuel efficient, and fuel flexible. Any hydrogen-rich material can serve as a potential fuel source for this developing technology. Possibilities include fossil-derived fuels, such as natural gas, petroleum distillates, liquid propane, and gasified coal, or renewable fuels, such as ethanol, methanol, or hydrogen. The U.S. Department of Energy (DOE) partnered with Ford Motor Company to develop full functional, zero-emission fuel-cell power-system technology for automotive applications. The purpose of this work was to demonstrate the technology in a complete laboratory propulsion system. This fuel-cell system, which operates on direct hydrogen, should achieve weights and volumes competitive with those of internal-combustion-engine propulsion systems. It should also have the potential to meet competitive production costs.