What Is Vehicle-to-Grid Technology?

Vehicle-to-grid, or V2G, is a technology that enables electric vehicles to discharge stored energy from their batteries back into the electrical grid or into a home or building. Instead of treating an EV as a passive load that only draws electricity, V2G transforms it into a mobile energy storage asset that can both consume and supply power based on grid needs.

The concept is powerful in aggregate. The average EV battery holds 60 to 100 kilowatt-hours of energy. If just 10% of the roughly 4 million EVs on US roads in 2025 were V2G-capable and available at any given time, they would represent roughly 30 gigawatt-hours of distributed storage, more than all grid-scale battery storage currently installed in the country.

How V2G Works Technically

V2G requires a bidirectional charger that can push power in both directions, from the grid to the vehicle and from the vehicle back to the grid. Standard EV chargers are unidirectional. Bidirectional chargers include additional power electronics and control systems that synchronize the vehicle’s DC battery output with the grid’s AC frequency and voltage requirements.

The vehicle’s onboard battery management system communicates with the charger and a cloud-based aggregation platform. The driver sets preferences, such as a minimum state of charge and departure time. The platform optimizes charging and discharging schedules across a fleet of enrolled vehicles, maximizing grid value while ensuring each vehicle is charged when the driver needs it.

V2G vs. V2H vs. V2L

Vehicle-to-grid is part of a broader family of bidirectional charging applications. Vehicle-to-home, or V2H, allows an EV to power a house during a grid outage, functioning as a backup generator. Vehicle-to-load, or V2L, provides power from the vehicle’s battery through an outlet on the car, useful for camping, tailgating, or powering tools at a worksite.

V2H is arguably the most immediately practical application. A 77 kilowatt-hour EV battery can power an average US home for two to three days during an outage. The Ford F-150 Lightning was one of the first mass-market vehicles to offer V2H capability, and it gained widespread attention during Texas power outages when owners used their trucks to keep their homes powered.

Grid Services and Economic Value

V2G-enabled vehicles can provide several valuable grid services. Frequency regulation is the most lucrative near-term application. EVs can respond to grid frequency deviations in milliseconds, faster than most conventional generators. Peak shaving allows utilities to draw on aggregated EV batteries during high-demand periods instead of firing up expensive peaker plants.

The economic value to vehicle owners depends on local electricity rates and grid service markets. Pilot programs have shown that V2G participants can earn $50 to $150 per month in grid service payments. In markets with high time-of-use rate differentials, vehicle owners can also profit from energy arbitrage by charging during cheap off-peak hours and discharging during expensive peak hours.

Barriers to Adoption

V2G adoption faces several barriers. Battery degradation is the most common concern. Every charge-discharge cycle contributes to battery wear. However, research suggests that managed V2G cycling at moderate depths of discharge has minimal incremental impact on battery life compared to normal driving patterns, particularly for newer battery chemistries with longer cycle life.

Automaker support is uneven. Most manufacturers have been cautious about enabling V2G, partly due to warranty concerns and partly because the revenue opportunity is still uncertain. Nissan has been the most active proponent, with V2G support in the Leaf since 2012. The industry is gradually moving toward broader bidirectional charging support as the grid value proposition becomes clearer and battery technology improves.