Vehicle-to-grid (V2G) works by running charging in reverse, under instructions from the grid side. A bidirectional charger converts your battery’s DC power into AC that matches the grid, an export meter records what leaves, and a utility programme or aggregator tells the car when to discharge — within limits you set. Your car never trades power on its own: the car, the charger and the grid operator all have to agree first.
Key Takeaways
- V2G is a controlled export: handshake, conversion, export, metering, then recharge.
- A utility programme or aggregator sends the discharge signal; you set the limits it must respect.
- Approval and export metering come first — and export stops in an outage, by design.
- Until a programme serves your address, one-way smart charging captures most of the everyday value.
The Export Path, Step by Step
Our overview of bidirectional charging: V2L, V2H and V2G explained defines the three types. This is what physically happens during one V2G event:
| Stage | What happens |
|---|---|
| 1. Handshake | The car and charger confirm both support bidirectional transfer, using the communication standard ISO 15118-20, and agree how much the car may export. |
| 2. Conversion | The charger inverts the battery’s DC power into AC synchronised with the grid’s voltage and frequency. A one-way charger cannot do this step at all. |
| 3. Export | Power flows out of the car, through the charger and into the local grid, where nearby homes and businesses use it. |
| 4. Metering | The export meter logs the kilowatt-hours sent out, so the programme can credit your account accurately. |
| 5. Recharge | After the event, the car refills — usually in off-peak hours — back to the level you need for driving. |
Who Tells Your Car to Discharge?
Not the charger, and not you in real time. A utility programme or an aggregator sends the dispatch signal when the grid needs support — typically during peak demand, such as a hot evening when air conditioning loads spike. One car is too small to matter to a grid operator, so aggregators combine many enrolled cars into a single resource that can be called on like a small power plant.
You set the boundaries the dispatch must respect:
- The minimum charge your battery must always keep for driving.
- The times the car is plugged in and available, and when it must be full by.
- Whether you take part in a given event at all — unplugging ends it.
The U.S. Department of Energy’s vehicle-to-everything (V2X) collaboration exists because this coordination between cars, chargers and grid operators is the hard part of V2G, not the hardware alone.
The Gatekeepers: Approval, Metering and Safety
- Interconnection approval. Before the first export, the utility approves the connection, because equipment that feeds the grid must meet its protection requirements.
- Export metering. Credits are paid on measured exports, so a meter or metering arrangement records what leaves the car.
- Anti-islanding protection. If the grid goes down, export stops automatically, so your car never energises lines that repair crews are working on. That is why V2G is not backup power — keeping a home running in an outage is vehicle-to-home’s job, with isolation equipment.
What Most Homes Use While V2G Rolls Out
V2G still works only for which EVs can do bidirectional charging — specific models, matched bidirectional chargers and a programme at your address. Most homes therefore charge one way and capture the off-peak savings that need no export at all. The EVDANCE EV-ACT5006T 48A Level 2 wall charger and the EVDANCE EV-ACS4005T 40A NACS portable charger are one-way units: they charge your car and cannot send power back to the grid.
Frequently Asked Questions
Can I sell electricity to the grid without joining a programme?
No. Export requires utility approval, metering and a programme or aggregator to dispatch and credit you. There is no direct way for a household to sell car battery power on its own.
Does V2G keep my home powered during a blackout?
No. For crew safety, export stops the moment the grid fails. Backup power at home is vehicle-to-home (V2H), which uses isolation equipment to run home circuits as a separate island.
Will the programme leave my battery empty?
No. You set a minimum charge and a ready-by time, and dispatch works inside those limits. The exact rules are set by each programme, so read them before enrolling.
Related Reading
- Bidirectional Charging Explained: V2L, V2H and V2G
- Is Bidirectional Charging Worth It?
- Which EVs Can Do Bidirectional Charging?
- When Will Vehicle-to-Home Be Available?
