V2G, or vehicle-to-grid, is a technology that lets electric vehicles send stored energy back to the power grid, essentially turning parked EVs into mobile batteries that utilities can draw from when electricity demand spikes. Instead of your car just pulling power from the grid to charge, the flow goes both ways. When the grid needs extra juice, your plugged-in EV can supply it, and you get compensated for the energy you provide.
How Bidirectional Charging Works
A standard EV charger moves electricity in one direction: from the grid into your car’s battery. V2G requires a bidirectional charger and a vehicle built to support two-way power flow. When your car is plugged in and not being driven, a grid operator can signal the charger to pull energy from the battery and push it back onto the grid. You set parameters like a minimum charge level so the car always has enough range when you need it.
The U.S. Department of Energy describes V2G as employing a bidirectional EV battery, when it’s not needed for driving, to participate in demand management as a grid resource. In practice, a grid operator can charge or discharge plugged-in vehicles on demand to help stabilize electricity supply. The car owner agrees to make their battery available during certain hours, and the system handles the rest automatically.
V2G is one piece of a broader bidirectional charging family. Vehicle-to-home (V2H) powers your house during an outage. Vehicle-to-load (V2L) lets you run appliances or tools directly from the car. Vehicle-to-building (V2B) feeds energy into a commercial building, sometimes as part of a microgrid. V2G is the most ambitious version because it connects your car to the wider electrical grid, not just your own property.
Why the Grid Needs Your Parked Car
Electricity grids face a fundamental challenge: supply and demand have to match in real time. On hot summer afternoons when air conditioners are running full blast, utilities scramble for extra generation capacity. At night, when solar panels stop producing, the grid loses a major source of clean power. V2G can help smooth out both problems.
The technical term is peak shaving, which means reducing the highest spikes in electricity demand by drawing on distributed storage instead of firing up expensive, often fossil-fuel-powered backup plants. A large-scale analysis of 480,000 plug-in EVs in Shenzhen, China, published in Nature Communications, found a potential peak-shaving capacity of 2,300 megawatts, enough to reduce the gap between lowest and highest daily electricity demand by 73%. That’s a massive buffer, and it comes from cars that would otherwise just be sitting in parking lots.
V2G also supports renewable energy integration. Solar and wind power are intermittent. EV batteries can absorb excess solar energy during the day and release it during evening hours when people come home and turn on lights, ovens, and televisions. This makes renewables more practical at scale without building as many dedicated grid-storage facilities.
What V2G Does to Your Battery
The most common concern about V2G is battery wear. Every charge and discharge cycle adds a small amount of stress to a lithium-ion battery, so using your car as a grid resource means more cycles than driving alone would produce. The real question is how much more degradation you’re actually looking at.
A 10-year study published in Applied Energy found that V2G increases total battery degradation by 9% to 14% over a decade. That sounds significant until you break it down. Most battery aging, roughly 85% to 90% of total degradation, comes from calendar aging: the battery simply getting older regardless of how you use it. The cycling portion (wear from charging and discharging) contributes only 10% to 15% of total degradation under normal driving. With V2G, that cycling share rises to 20% to 25%. In absolute terms, V2G adds about 0.31% extra total degradation per year for around 33 additional charge/discharge cycles monthly.
For most owners, this translates to a modest reduction in battery life that can be offset by financial compensation. V2G strategies that prioritize keeping your battery above a comfortable charge level (most participants prefer a minimum of around 70%) reduce degradation costs by 30% to 40% compared to aggressive grid-use schedules, with only minimal loss in grid performance.
How Much You Can Earn
V2G compensation varies widely depending on your utility, location, and how much grid access you allow. Programs are still in early stages in most markets, and payment structures range from direct per-kilowatt-hour credits to monthly electricity bill reductions. A study of Norwegian EV owners found that participants expected an average reduction of about $144 per month on their electricity bills, roughly 72% of their typical monthly bill, as fair compensation for making their battery available.
Revenue potential depends on grid conditions in your area. Regions with high peak electricity prices or frequent demand spikes offer more earning opportunity. Some pilot programs pay owners for frequency regulation, a grid service where small bursts of energy are injected or absorbed in seconds to keep the grid’s electrical frequency stable. This is one of the highest-value grid services and doesn’t require large amounts of energy, making it well suited to EV batteries.
Which EVs Support Bidirectional Charging
Not every electric vehicle can send power back out. The car’s onboard electronics have to be designed for two-way power flow, and it needs to be paired with a compatible bidirectional charger. As of 2025, a growing number of production vehicles offer some form of bidirectional capability in the U.S., though full V2G (feeding back to the grid) remains less common than V2L or V2H.
The Ford F-150 Lightning is one of the most prominent examples, with a 9.5 kW bidirectional supply rate and a separate smaller battery that helps reduce wear on the main pack during power-sharing. The 2025 Tesla Cybertruck offers 11.5 kW through outlets in the bed. The 2026 Cadillac Escalade iQ leads the pack at 19.2 kW using GM’s PowerShift charger adapter.
On the more affordable end, the 2025 Hyundai Ioniq 5 and 2025 Genesis GV60 both support bidirectional charging at 3.6 kW, built on Hyundai’s shared E-GMP platform. The 2026 Kia EV9 starts at 3.6 kW but can reach 12 kW with an optional Quasar 2 bidirectional charger. The 2026 Polestar 4 comes standard with 10.3 kW bidirectional capability, and the 2026 Nissan Leaf includes it at a more modest 1.5 kW. The Nissan Leaf was actually one of the first EVs ever to offer bidirectional charging, dating back to earlier generations using the CHAdeMO connector.
The Standards Challenge
One of the biggest technical hurdles for V2G has been getting cars and chargers from different manufacturers to speak the same language. The international standard designed to solve this is ISO 15118-20, which builds on an earlier version by adding support for bidirectional power transfer, stronger security protocols, and wireless charging communication.
Implementation has been slow. A 2025 study achieved what researchers described as the first independent, fully compliant bidirectional charging session using ISO 15118-20 with a commercial vehicle (the Kia EV9). Until now, automakers have largely relied on customized versions of the older ISO 15118-2 standard, which works but locks out interoperability between different brands. Automakers including Hyundai, Ford, Volkswagen, and Polestar are collaborating with charger manufacturers behind the scenes to get ISO 15118-20 working, but full transport-layer security integration between vehicle and charger remains a challenge.
On the efficiency front, the latest generation of bidirectional chargers performs well at higher power levels, reaching 93% to 97% efficiency during charging at 32 amps. Discharging efficiency is lower, ranging from 60% at very low currents to 93% at higher ones. Compared to older CHAdeMO-based bidirectional systems, the new generation shows a 7% to 15% improvement in efficiency, which matters because every percentage point lost during conversion is energy you gave away for free.
Regulatory Groundwork in the U.S.
For V2G to work at scale, EVs need access to wholesale electricity markets, the exchanges where power is bought and sold in real time. FERC Order 2222, issued by the Federal Energy Regulatory Commission, lays the groundwork for this. The order requires regional grid operators to allow distributed energy resources, including EVs and their charging equipment, to participate in wholesale markets through aggregations. That means your single EV doesn’t need to meet the minimum size requirements alone. An aggregator (a company that bundles hundreds or thousands of EVs together) can pool their capacity and bid into the market as a single resource, with aggregations as small as 100 kW.
The order also establishes coordination requirements between grid operators, aggregators, local utilities, and state regulators. FERC specified that these rules shouldn’t create undue barriers for EV owners and aggregators while still allowing utilities and local regulators to protect distribution system safety and reliability. In practice, this means your local utility retains oversight of what happens on its wires, but it can’t simply block V2G participation without justification.
State-level programs are developing in parallel. Some states have launched V2G pilot programs with specific utilities, while others are updating interconnection rules to accommodate bidirectional chargers. The regulatory landscape is still catching up to the technology, but the federal framework is now in place for EVs to earn their keep as grid assets.