A plug-in hybrid electric vehicle (PHEV) is a hybrid vehicle with batteries that can be recharged by connecting a plug to an external electric power source.
It shares the characteristics of both traditional hybrid electric vehicles (also called charge-maintaining hybrid electric vehicles), having an electric motor and an internal combustion engine; and of battery electric vehicles, also having a plug to connect to the electrical grid (it is a plug-in vehicle).
Most PHEVs on the road today are passenger cars, but there are also PHEV versions of commercial vehicles and vans, utility trucks, buses, trains, motorcycles, scooters, and military vehicles. They are sometimes called grid-connected hybrids, gas-optional hybrids, or GO-HEVs.
The cost for electricity to power plug-in hybrids for all-electric operation has been estimated at less than one quarter of the cost of gasoline. Compared to conventional vehicles, PHEVs can reduce air pollution, dependence on petroleum and fossil fuels, and greenhouse gas emissions that contribute to global warming.
Plug-in hybrids use no fossil fuel during their all-electric range if their batteries are charged from nuclear or renewable electricity. Other benefits include improved national energy security, fewer fill-ups at the filling station, the convenience of home recharging, opportunities to provide emergency backup power in the home, and vehicle-to-grid (V2G ) applications.