A fuel-cell engine is at least twice as efficient as conventional engines. For example, a typical combustion-based power plant generates electricity at efficiencies of 33 to 35 percent, while fuel-cell plants can generate electricity at efficiencies of up to 60 percent. When fuel-cells are used to generate electricity and heat (co-generation), they can reach efficiencies of up to 85 percent. Internal-combustion engines in today's automobiles convert less than 30 percent of the energy in gasoline into power that moves the vehicle. Vehicles using electric motors powered by hydrogen fuel-cells are much more energy efficient, utilizing 40-60 percent of the fuel's energy. Even fuel-cell vehicles that reform hydrogen from gasoline can use about 40 percent of the energy in the fuel.