A Plug-in Hybrid Electric Vehicle (PHEV) has a petrol or in some cases a diesel engine and an electric motor; both can drive the vehicle. Plug-in Hybrid Vehicles offer the best of both worlds, with a zero-emission range of around 20-30 miles, and then the convenience of a petrol or diesel engine to drive longer distances.
Plug-in hybrid vehicles reduce overall emissions by offering zero emission operation for a limited range before the engine is used. The zero-emission range should be prioritised for use in city centres to improve the air quality in urban areas. Environmental and cost savings increase the more the vehicle is driven in electric mode.