A utility's electric meter spinning backwards, pulling power from souped-up batteries in a modified Prius, drew Silicon Valley leaders to a Sunnyvale, CA parking lot today.

At an event put on by the Silicon Valley Leadership Group at the headquarters of chipmaker AMD, local utility Pacific Gas and Electric (PG&E) gave what it called the first-ever Vehicle-to-Grid (V2G) public technology demonstration.

PG&E's Sven Thesen, supervisor of clean air transportation, shows off V2G prototype, that, as a side benefit, gets 100 MPG with its new souped-up battery pack (photo) >>

Industry watchers have talked for some time about the possibility of using batteries in hybrid—and in the future, all-electric vehicles—as a way to "add something to that's never been added to the grid before: storage," said Bob Howard, PG&E vice president of gas transmission and distribution.

The plan: drivers, who charged their vehicles at night when power was cheap, could commute by day, plug their vehicles in at their destinations, and receive rebates if the power grid needed electricity at time of peak demand and pulled power from their batteries.

"At night, electricity is very cheap, very plentiful. You can't turn down your nuclear reactors at night. A lot of the wind energy comes in at night, and utilities don't know what to do with it," Sass Somekh, President Emeritus of Novellus, told a group assembled for the event.

"The utilities would then be able to borrow back during the day the electricity two-to-three times what you would pay at night."

And that's potentially less expensive and better for the environment than turning on a fossil-fuel based generator, PG&E touted in a press release.

Today, the vision took a baby step closer to reality.

PG&E's demonstration was of prototype V2G technology. The components inside weren't very sophisticated, admitted Sven Thesen of PG&E, giving Cleantech.com a look at the vehicle.

Inside the trunk of the Prius was a charging pack with an AC to DC converter, a Sunny Boy inverter—the same type sold today for solar and wind installations—and special software for managing power to and from a 9 Kw/H bank of Lithium Ion batteries, which replaced the Prius' factory nickel metal hydride batteries.

Under the hood, or in this case, the trunk (photo) >>

Upon inserting a standard U.S. 110-volt electrical cable into a connector on the car, a nearby power meter, using prototype advanced metering software and hardware, began spinning backwards after a short delay.

The consumer's experience should be easy, Thesen said, under PG&E's advanced meter initiative.

"Just plug your vehicle in at night, and we'll send a signal at 11, 12 or 1 a.m. to start your charging. When you get up in the morning, your car will be fully charged. You'll plug your car in at work. Maybe we'll need your electricity, and maybe we won't. If we do, you'll see a credit on your bill, and if not, you'll see nothing."

PG&E doesn't expect wide-scale deployment to happen before 2012, possibly even 2015 or later, acknowledging a chicken-and-egg problem.

"The future is going to depend on how many pluggable hybrids are out there, how do they actually work, and how good our advanced metering initiative is," PG&E's Thesen said to Cleantech.com. "You may have to wait a while to be able to do this at home. Large parking lots will come first," he said.

While technically possible to feed energy back to the grid with Priuses and other hybrids today, PG&E's Thesen estimated the proper conversions would cost as much as $70,000—not making it very attractive at this time.

PG&E’s prototype PHEV was converted in partnership with the Bay Area Air Quality Management District and Energy CS.