Plug-in Hybrid Vehicles (PHEV) have all the functionality of full Hybrid technology, with the added advantage that they can be charged from an external electricity supply. Plug-in Hybrids use two sources of power like a Hybrid, but with a larger high voltage battery, enabling you to drive longer distances on All-Electric power. The larger capacity of the battery makes them capable of zero-emissions while driving for ranges of up to 30 miles (50 kilometres), with the ability to switch to Hybrid mode to conserve battery life and to petrol or diesel-only for longer journeys.