The technology, developed by Audi and Hager Group and being trialled on the Audi e-tron electric SUV, allows electric cars to not only receive electricity from home stores via wall chargers but also give the stored energy back.

In Audi’s test grid, the e-tron operated with a DC wallbox with a charging capacity of up to 12kW, as well as a home storage unit with a capacity of 9kW. Because of the DC voltage level in the overall grid, Audi claims the connection between the home electricity system and the e-tron didn’t require an inverter, making it very efficient.

Audi said this system would be particularly useful for customers who have solar panels, with the car being able to store home-generated electricity while the sun is shining and return it during times when it isn’t.

An Audi spokesperson said: “Bi-directional charging at home – also known as Vehicle to Home (V2H) – has great potential to reduce the home-owner’s electricity costs and increase network stability. As a further expansion stage, in combination with a home storage unit, it’s possible to achieve near-complete energy independence and increased security of supply in the event of a blackout.”

Ulrich Reiner, project manager at Hager Group says, “Using the battery of electric vehicles to contribute to climate protection while lowering electricity costs at the same time is a vision that we have found fascinating since the very beginning. And we have found an ideal partner in Audi.”

Martin Dehm, technical project manager for bidirectional charging at Audi says, “Electric mobility is bringing the automotive industry and the energy sector closer together. The battery of an Audi e-tron could supply a single-family home with energy for around one week independently. Looking ahead, we want to make this potential accessible and make the electric car part of the energy transition as an energy storage device on four wheels.”