Vehicle-to-Grid (V2G) and Vehicle-to-Home Explained

A typical EV battery holds 50–80 kWh — several days' worth of an average home's electricity. Bidirectional charging lets that energy flow out of the car as well as in. There are three flavours, and the letters matter.

Why it matters for renewables

Wind and solar generation rises and falls, and the grid needs storage to smooth it out. Millions of parked EVs add up to an enormous distributed battery. Charging when there is surplus renewable power and discharging a little at the evening peak lets the grid use more clean energy and fewer gas 'peaker' plants. Trials in the UK, Netherlands, Japan and Australia have paid participating drivers hundreds of pounds or dollars a year.

Does it damage the battery?

This is the most common worry. Studies so far suggest that well-managed V2G — shallow, controlled cycles within the middle of the battery's charge range — adds very little degradation, and some research suggests smart management can even reduce it compared with leaving a car sitting at 100% for days. Manufacturers that support V2G cover it under warranty; a car that does not officially support it should not be used with a bidirectional charger.

What you need

• A car that supports bidirectional charging (increasingly common on new models — check the spec sheet for V2L, V2H or V2G).
• A bidirectional home charger, which costs more than a standard wallbox.
• For V2G, an electricity tariff or aggregator that pays for exports, and grid rules that allow it in your country.
• The car parked and plugged in during the hours the grid wants power — usually the evening peak.

Even without V2G, V2L is a genuinely useful feature: running a fridge in a power cut, powering tools at a site, or a kettle at a campsite from the car.