How Electric Cars Could Save the Grid

Dec. 27, 2007 -- Buy a new, gas-powered auto and it depreciates by hundreds, even thousands of dollars as soon as you drive it off the lot. But buy an electric car and you could receive hundreds, even thousands, of dollars a year, just for plugging it in.

The cash benefit is just one of many in the so-called "vehicle to grid" -- or V2G -- project being developed by researchers at the University of Delaware.

Their idea is simple: electric cars have to plug into the power grid anyway to get their batteries recharged. Why not use those batteries collectively as electricity "sponges" to soak up and wring out the excess power from utility companies that fluctuates notoriously on any given day?

Utility companies would benefit because they'd have a place to store energy; car owners would receive a fee to participate; and car manufacturers would have an attractive selling-point by which to promote their vehicles.

And it doesn't take much to get started.

"If you can collect 300 cars, that fleet is sufficient for a utility operator to run a V2G operation," said team member Ajay Prasad, professor of mechanical engineering at the University of Delaware in Newark.

Car owners drive, on average, about one to two hours per day. So statistically, a large percentage of the total population of cars is sitting idle at any given time.

At the same time, electric grid operators play a balancing game of generating electricity that will meet customer demand. On top of that, they must pay to keep a generator fired up that will serve as a back up in the event of a catastrophic failure on the grid. Until the failure, that energy is wasted.

But if all of those parked cars were electric and plugged into the grid, the utility operator could automatically draw on the batteries exactly as needed, meeting demand. And instead of paying a power plant to generate energy that would be wasted anyway, they would pay a fee to the electric car owner for making the battery available.