Usually, yes — when the car is home while the sun is shining. Each kilowatt-hour of solar the car uses is worth the grid price you did not pay, minus the export payment you gave up by not selling that energy instead. Both numbers sit on your own bill and export agreement, and the gap between them is your saving.
Key Takeaways
- A solar kilowatt-hour in the car is worth your import price minus your export payment — both from your own documents.
- The saving is biggest when export pays little and the car is home in the sun.
- Cheap off-peak night rates or a high export payment can shrink the advantage to almost nothing.
- No headline figure survives contact with your tariff; run the arithmetic with your two prices.
The Only Comparison That Matters
Solar energy used at home has two possible values. Exported, it earns whatever your plan pays for feed-in energy — often little, sometimes nothing. Used by the car, it displaces a kilowatt-hour you would otherwise have bought at your full import price. So the value of a solar-charged kilowatt-hour is your import price minus your export payment. Where export pays nothing, the whole import price is the saving; where export pays close to it, the gain nearly disappears. Both figures come from your tariff documents, not from a headline.
A Worked Example, With Its Labels On
Take a 10 kWh daytime session. At the U.S. average residential price of 18.31 cents per kWh (U.S. EIA figure, July 2026), charging from the grid would cost about $1.83. If your plan paid an illustrative 5 cents per kWh for exports (a figure invented for this example — real payments vary, and many plans pay far less or nothing), sending that energy to the grid instead would have earned about $0.50. So charging from solar was worth roughly $1.33 more than exporting the same energy. Replace both prices with the two on your own documents and the same arithmetic gives your answer.
The Variables That Decide Your Number
| Variable | Where you find it | How it moves the saving |
|---|---|---|
| Your import price | Your electricity bill or tariff sheet | The higher it is, the more each solar kilowatt-hour in the car is worth |
| Your export payment | Your feed-in agreement — it may be zero | The higher it is, the less you gain by using the energy yourself |
| When the car is home | Your routine | Solar only helps sessions that overlap the sunny hours; evening cars charge on grid prices |
| Array output versus the car’s needs | Your inverter app and your driving pattern | A small array or a large daily mileage caps how much of the charging can be solar at all |
| How the session runs | Your charger and car settings | Surplus-following or sunny-hours scheduling uses more of your own generation than a full-rate session that blends in grid power |
When Solar Charging Saves Little
Three situations shrink the saving toward zero. The car is away at work all day, so most charging happens at night on grid energy regardless of the roof. The export payment is close to the import price, so selling and self-using are worth almost the same. Or your plan has a very cheap off-peak night rate, which can make overnight grid charging the better buy even for a car that is home all day — the comparison our article on smart charging and time-of-use scheduling works through.
What the Charger Contributes
Any charger can charge during solar hours; scheduling and adjustable current simply help you use more of your own generation instead of grid power. Stated plainly, no EVDANCE listing states a solar mode or surplus feature. The EV-ACT3204E wallbox states app control and RFID, and the EV-ACS3210E states app control and energy monitoring — the tool that shows what your sessions drew, so you can run the comparison with your own numbers. The wider range is on our residential charging page, and how the pieces fit together is covered in our guide to solar panels and EV chargers.
Frequently Asked Questions
Is charging from solar free, then?
Not quite. Its cost is the export payment you gave up — which may be zero, in which case the energy is effectively free to you.
Does adding a home battery increase the saving?
It can move midday solar into evening charging, which helps cars that are away in the day. But the battery is a separate purchase, so the honest comparison is its cost against the same import-minus-export gap applied to the energy it would shift.
Should I stop exporting altogether?
No. Only the surplus the car can actually take while it is home counts. Energy beyond that is still worth exporting at whatever your plan pays.
Related Reading
- Solar Panels and EV Chargers: How to Charge Your Car With Sunshine
- Smart Charging and Time-of-Use Tariffs: How Scheduling Cuts EV Charging Costs
- Bidirectional Charging Explained: V2L, V2H and V2G
