A plug-in hybrid electric vehicle (PHEV) is a hybrid vehicle with batteries that can be recharged by connecting a plug to an 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 a internal combustion engine, and of battery electric vehicles, also having a plug to connect to the electric 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.
Chinese battery manufacturer and automaker BYD Auto launched to the domestic fleet market on December 15, 2008, the F3DM PHEV-68 (PHEV109km) hatchback, sold for 149,800 yuan (USD $22,000), the F3DM became first commercial plug-in hybrid available to the general public ever. Major automakers, including Toyota, General Motors, Ford, California startups Fisker Automotive and Aptera Motors, Volkswagen, and Volvo have announced their intention or have already scheduled the introduction of production PHEV automobiles between 2010 and 2012. As of 2009, most PHEVs on the road in the U.S. are conversions of 2004 or later Toyota Prius and Ford Escape models, which have had plug-in charging and more batteries added and their electric-only range extended. Several countries, including the United States and several European countries, have enacted laws to facilitate the introduction of PHEVs through tax credits, emissions mandates, and by financing research and development of advanced batteries and other related technologies. Introduction of PHEVs also benefits from laws and regulations enacted for hybrid vehicles.