A battery on wheels: The Bi-directional concept
Until now, the relationship between the house and the electric car was one-way: the grid (or solar panels) provided the energy to charge the car. With technology V2H (Vehicle-to-Home) and V2G (Vehicle-to-Grid), the flow becomes bidirectional. Your electric car, which has a huge battery (50 to 100 kWh, compared to 10 kWh for a standard domestic battery), can now power your home in the evening, or even feed back into the Swiss network (V2G) during peak periods.
V2H: Vehicle-to-Home (Absolute self-consumption)
V2H is the ultimate stage of solar self-consumption. The principle is simple in 2026:
1. The day (Midday) : Your solar panels are running at full capacity. Your car, connected to its bidirectional terminal (e.g.: Wallbox Quasar 2, SunPower Drive), absorbs the free surplus.
2. In the evening (19h) : The sun is setting. You turn on the oven, the heat pump and the lights. Instead of buying expensive electricity from your cantonal GRD, the car slowly “discharges” itself to power the house.
3. Result : You save the purchase of a physical domestic battery at 8'000 CHF, while having a reserve capacity 7 times greater.
V2G: Vehicle-to-Grid (The energy market)
V2G goes further. In agreement with your network manager (e.g.: SIG, Romande Energie, BKW), your car can, for a few tens of minutes per year at critical times (e.g.: cold spell in February at 18h), reinject electricity into the French-speaking network to relieve it. In exchange, you are paid a preferential rate. This is called “balancing power draw”.
Material reality in Switzerland (2026)
The promise is sublime, but the technical reality requires ticking several boxes:
- The car must be compatible: The CHAdeMO standard (Japanese cars like the Nissan Leaf) historically managed V2H. Now it's the norm CCS (Combo) with ISO 15118-20 which standardizes bidirectional charging in AC or DC for European and South Korean brands (VW MG Group, Hyundai/Kia).
- The terminal must be bidirectional: These terminals (often domestic DC chargers) cost more than a classic terminal (count 4'000 to 6'000 CHF for materials alone, compared to 1'500 CHF for a classic AC terminal).
- The inverter or management system (EMS): It must orchestrate the flows between the panels, the house, the network and the car without tripping up the installation.
The expert's opinion
"In 2026, V2H will move from the prototype stage to a real commercial option in Switzerland. However, if you use your electric car to go to work every day of the week (and it is therefore absent during the day when the sun is shining), V2H loses its meaning. This technology should be favored if the car (or a second car) often stays at home during the day (teleworking, part-time)."
Profitability compared to a wall battery
Buying a bidirectional terminal (around 3'000 CHF more expensive than a traditional one) remains financially much more advantageous than buying a physical domestic battery (Lithium 10 kWh at 8'000 CHF). The only obstacle lies in physically and systematically plugging in the cable (unless there is a future bidirectional induction charge) as soon as you park, so that the computer "brain" of the house can play with your excess kW.