EV batteries can now store excess power and feed it back when needed. Munich engineer Moritz Rupp calls it obvious, as the expensive batteries otherwise sit idle for 23 hours a day. The technology allows use for home electricity or selling to the grid.
Düsseldorf. EV batteries average 64 kilowatt-hours, far larger than typical home storage units of 5 to 10 kWh. "And this valuable, large battery sits statistically unused for 23 out of 24 hours a day because the car is parked," says 39-year-old electrical engineer Moritz Rupp from Munich.
With bidirectional charging, the vehicle stores excess midday solar power from rooftop PV systems and releases it to the home in the evening. This saves residents from buying expensive grid electricity. Alternatively, it can be fed into the public grid at peak evening prices via the Leipzig power exchange.
"Some things are so obvious and logical that you really wonder why we haven't done this for years," Rupp says. "It's actually a no-brainer." The advanced form is known as Vehicle-to-Grid, or in German 'from vehicle to grid'.