What is vehicle-to-grid (V2G)?

How it works

V2G depends on bidirectional charging. A bidirectional electric vehicle (EV) can take in energy from a charger and discharge it to an outside load, the U.S. Department of Energy's Federal Energy Management Program explains. That requires similarly capable charging equipment, the program says. Power sent to the grid is V2G. Power backing up a building is vehicle-to-building (V2B). A light-duty EV battery holds roughly 15 to 100 kilowatt-hours, the program says.

A 2005 Journal of Power Sources paper by Willett Kempton and Jasna Tomić laid out an engineering and economic case for V2G. They noted that personal vehicles are used for transport only about 4% of the time. They argued V2G suits quick-response services that balance swings in demand and cover unexpected equipment failures, not constant baseload supply.

The University of Delaware, working with regional grid operator PJM, demonstrated the first grid revenue from V2G, the Energy Department page says. PJM pays the university the market rate for keeping vehicles plugged in and available. The undated page puts that at roughly $1,200 a year per vehicle.

The standards behind it

ISO 15118-20, published in April 2022 and amended in 2026, defines the messages a vehicle and charger exchange for bidirectional power transfer. SAE J3072, last revised in June 2024, sets requirements for a grid-support inverter built into the vehicle. These electronics feed its power to the grid. J3072 also covers the communication by which a charger authorizes that inverter to discharge at a site.

Where things stand in 2026

Utility Dive reported in July 2026 that utility adoption of full-scale V2G programs in the United States was limited. It said only some EVs sold there are bidirectional-capable. General Motors (GM) said in June 2026 it had 250,000 such vehicles on the road, the outlet reported. GM commissioned a study from consultancy E3. The study estimated V2G could deliver five to 15 times more value per vehicle than one-way managed charging in many electricity markets. It put the nationwide potential at about $7 billion by 2030. E3 also said regulatory and program design barriers limit how much of that value utilities and ratepayers can capture.

That month GM also said it would release a firmware update giving its existing vehicle-to-home systems full V2G capability, Utility Dive reported. It said Rivian partnered that month with ChargeScape, a platform that supports utility managed and bidirectional charging programs.