Vehicle-to-grid and bidirectional charging, without the hype
A depot full of parked vehicles is a huge battery. Vehicle-to-grid could one day use it to cut peaks or earn revenue — here's what's genuinely real today, and what's still coming.
Last updated 15 August 2026
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Few ideas in fleet electrification are as exciting — or as over-promised — as vehicle-to-grid. The pitch is irresistible: a depot full of parked electric vehicles is a giant battery, so why not use it to cut your peaks or even earn money? The concept is sound and the direction of travel is real. But an independent guide owes you the honest version: what works today, what’s still maturing, and when it’s worth planning for.
What V2G actually is
Normal charging is one-way: power flows into the vehicle. Vehicle-to-grid (V2G) — part of a broader family called V2X — lets power flow out of a parked vehicle’s battery too, back to your building or the grid. Because your fleet sits idle for long stretches, all that parked capacity could, in principle, be tapped when it’s valuable and topped up when power is cheap. It’s the same logic as an on-site battery, using the batteries you already own.
Where it’s real today
V2G works, and there are live projects — but it needs the right pieces: vehicles that support bidirectional charging (still a minority), compatible bidirectional chargers (more expensive than standard ones), and commercial arrangements to make it pay. Those pieces are arriving, not universal. For a depot buying today, treat V2G as an emerging capability to keep an eye on rather than a feature to build the plan around.
V2G versus a stationary battery
If your goal is to shave peaks or store cheap energy, a dedicated battery is the proven route today: it’s always available, sized for the job, and independent of whether vehicles are plugged in. V2G’s appeal is using capacity you’ve already paid for in the vehicles — but that capacity comes and goes as vehicles leave, and every cycle is wear on a battery you rely on for driving. For most depots now, a stationary battery is the dependable choice and V2G the interesting future option.
When it’s worth planning for
V2G becomes worth serious attention when your vehicles and chargers support it as standard, and when the flexibility payments justify the extra hardware cost and battery wear. Some forward-looking operators are specifying V2G-capable equipment now so they’re ready when the economics mature — a reasonable hedge if it’s cheap to include, but not something to pay a large premium for on today’s numbers.
The bottom line
Vehicle-to-grid is a genuinely promising idea that will matter more over time, not a finished product to deploy at scale today. Get your smart charging foundation right first — it delivers most of the value now — and keep V2G on your radar as vehicles, chargers and markets catch up. When the pieces line up, the parked fleet becomes an asset; until then, plan around what’s proven.
Go deeper — articles in this guide
- Vehicle-to-grid explained without the hype V2G lets a parked vehicle send power back out — to your building or the grid. Here's the honest version of what it is and where it stands.
- Is V2G worth planning for at your depot yet? For most depots, not yet as a core feature — but specifying V2G-capable kit can be a cheap hedge. Here's how to judge it.
- What vehicles and chargers support bidirectional charging V2G needs both a capable vehicle and a bidirectional charger, plus the right standards. Here's what to check before counting on it.
- V2G vs a stationary battery: which makes sense when? Both use stored energy to cut peaks and store cheap power. A stationary battery is the reliable choice today; V2G is the future option.