A plug-in electric vehicle (PEV) is any motor vehicle that can be recharged from an external source of electricity, such as wall sockets, and the electricity stored in the rechargeable battery packs drives or contributes to drive the wheels. PEV is a subset of electric vehicles that includes all-electric or battery electric vehicles (BEVs), plug-in hybrid vehicles (PHEVs), and electric vehicle conversions of hybrid electric vehicles and conventional internal combustion engine vehicles.
Plug-in cars have several benefits compared to conventional internal combustion engine vehicles. They have lower operating and maintenance costs, and produce little or no local air pollution. They reduce dependence on petroleum and may reduce greenhouse gas emissions from the onboard source of power, depending on the fuel and technology used for electricity generation to charge the batteries. Plug-in hybrids capture most of these benefits when they are operating in all-electric mode. Despite their potential benefits, market penetration of plug-in electric vehicles has been slower than expected as adoption faces several hurdles and limitations.
Several national and local governments have established tax credits, subsidies, and other incentives to promote the introduction and adoption in the mass market of plug-in electric vehicles depending on their battery size and all-electric range. As of September 2015[update], there were almost 70 models of highway legal plug-in electric passenger cars and light-duty utility vans available for retail sales in the world. The Nissan Leaf is the world's all-time top selling highway-capable all-electric car, with global sales of more than 200,000 units by early December 2015.
Over one million highway-capable plug-in electric passenger cars and light utility vehicles have been sold worldwide, with the United States as the market leader with a stock of over 363,000 plug-in electric cars delivered since 2008 through August 2015, representing 36.3% of global sales. As of August 2015[update], China ranked second with over 157,000 units sold since 2011 (15.7%), followed by Japan with more than 121,000 plug-in units sold since 2009 (12.1%). As of June 2015[update], over 310,000 light-duty plug-in electric vehicles have been registered in the European market since 2010. In the heavy-duty segment, China is the world's leader, with over 65,000 buses and sanitation vehicles sold through August 2015.