Electricity is considered an alternative fuel under the Energy Policy Act of 1992. Plug-in hybrid electric vehicles (PHEVs) and all-electric vehicles (EVs) store electricity in batteries to power one or more electric motors. The batteries are charged primarily by plugging in to off-board sources of electricity, produced from oil, coal, nuclear energy, hydropower, natural gas, wind energy, solar energy, and stored hydrogen.
HEVs are primarily powered by an internal combustion engine that runs on conventional or alternative fuel and an electric motor that uses energy stored in a battery. The battery is charged through regenerative braking and by the internal combustion engine and is not plugged in to charge.
PHEVs are powered by an internal combustion engine that can run on conventional or alternative fuel and an electric motor that uses energy stored in a battery. The vehicle can be plugged in to an electric power source to charge the battery. Some can travel more than 70 miles on electricity alone, and all can operate solely on gasoline (similar to a conventional hybrid).