Fuel cell vehicles (FCVs) may not reach the mass market for a decade or more, but a limited number will be available for sale or lease in 2005-06 to demonstration fleets in areas with a readily accessible hydrogen supply. FCVs are propelled by electric motors powered by fuel cells, which produce electricity from the chemical energy of hydrogen. Fuel cell technology is more efficient than internal combustion engines and environmentally cleaner—the only byproduct of a hydrogen fuel cell is water. However, many challenges must be overcome before FCVs are mass-marketed and sold at local dealerships. For more information about FCVs, visit www.fueleconomy.gov and the Hydrogen, Fuel Cells & Infrastructure Technologies Program Web site at www.eere.energy.gov/hydrogenandfuelcells/.