How Electric Car Batteries Might Aid the Grid (and Win Over Drivers)

Electric cars are more expensive than gasoline models largely because batteries cost so much. But new technology could turn those pricey devices into an asset, giving owners benefits like reduced utility bills, lower lease payments or free parking.

Ford Motor, General Motors, BMW and other automakers are exploring how electric-car batteries could be used to store excess renewable energy to help utilities deal with fluctuations in supply and demand for power. Automakers would make money by serving as intermediaries between car owners and power suppliers.

Millions of cars could be thought of as a huge energy system that, for the first time, will be connected to another enormous energy system, the electrical grid, said Matthias Preindl, an associate professor of power electronic systems at Columbia University.

“We’re just at the starting point,” Dr. Preindl said. “They will interact more in the future, and they can potentially support one another — or stress one another.”

A large flat screen on the wall of the Munich offices of the Mobility House, a firm whose investors include Mercedes-Benz and Renault, illustrates one way that carmakers could profit while helping to stabilize the grid.

The graphs and numbers on the screen provide a real-time picture of a European energy market where investors and utilities buy and sell electricity. The price changes from minute to minute as supply and demand surge or ebb.