The Nissan Leaf sitting in Paul Kershaw¡¯s driveway outside Cambridge, England, might look like just another car, waiting for its driver to take it for a spin. But the electric vehicle has been more than a means of transportation. It¡¯s also powered appliances, streetlights and other grid-reliant machinery in the neighborhood.

The exchange of power is part of a trial launched in 2019 by Ovo Energy Ltd., the U.K.¡¯s second biggest energy supplier. When Kershaw heard about the program, he applied to be one of 330 people to register his car as an energy-storage device.

¡°I use my car only 1% of the time, so knowing that my car is there, and it¡¯s active and it¡¯s doing something ¡ª it¡¯s being used to balance the grid,¡± Kershaw said, ¡°it¡¯s great knowing that.¡±