Connecting electric cars to a wider energy grid in places like San Diego could even out electricity production levels and earn consumers money by sharing power with the grid. "The white Toyota Scion xB parked in a corner of the vast convention center here doesn't look too unusual, until you notice the fat cable plugged into its bright orange front grille. But its owners say it might be the smallest unit of California's electrical grid. The car, a plug-in hybrid electric vehicle, has been retrofitted by AC Propulsion to respond to signals from the California Independent System Operator -- giving it the ability to send power from its battery back to the grid. It's on display here at the annual meeting of the American Association for the Advancement of Science as proponents of so-called 'vehicle to grid,' or V2G, technology make their case. Backers say V2G could help balance the country's supply and demand for power, especially as renewable energy from intermittent sources like wind and solar becomes a larger part of America's energy mix. With enough cars participating, a V2G system could help buffer ups and downs in power production by allowing utilities cheap storage for their excess power."