How Electric Cars Could Save the Grid

How Electric Cars Could Save the Grid

Backup Power
The "vehicle to grid" project being developed by researchers at the University of Delaware aims to use the idle batteries of electric cars as electricity "sponges" to soak up and wring out the excess power from utility companies. 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.

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.

"The utilities understand the value immediately," said team leader Willett Kempton, associate professor of urban affairs and public policy, also at the University of Delaware.

Communication between the power company and the electric car owner would occur via the Internet or some other wireless network, such as a cellular phone network.

Car manufacturers may be the last to clue in, though. For the system to have the most value, electric cars need to be equipped with a high, 80-amp/240-volt plug -- something a little more powerful than the plug on an electric dryer. (An electrician can install the corresponding outlet into any home.) But most of the existing electric hybrid cars come equipped with a low, 15-amp, 110-volt plug.

Sure, the low-amp plugs work, said Kempton, but if the electric car owner is selling electricity back to the grid, they want to sell as much as possible. A 15-amp plug could net a car owner about $400 year, whereas an 80-amp plug could net $4,000, he said.

The good news is that, unlike other alternative energy sources, such as hydrogen fuel, the infrastructure for electric cars is already there.

"The only thing you have to do is enhance it a little bit," said Victor Udo, manger of business planning and research at Pepco Holdings, a utility in Wilmington, Del., that is working with the V2G project to help put the idea into action.

To date, the V2G team successfully connected one prototype electric car to the grid and was able to charge the battery as well as draw energy from it. They are now working to do the same with four to six vehicles. Eventually they will work with local utility customers to test a fleet of 100 to 300 cars -- enough to supply a utility company with 3 megawatts of backup power.

In the future, electric vehicles could do more than provide backup energy. If just a quarter of the nation's cars were electric -- about 50 million cars -- the power capacity of those batteries would be equal to 700 gigawatts, the entire power production capacity in the United States today.