Reservoir Hill writes "A team at the University of Delaware has created a system that enables vehicles to not only run on electricity alone, but also to generate revenue by storing and providing electricity for utilities. The technology, known as V2G, for vehicle-to-grid, lets electricity flow from the car's battery to power lines and back. When the car is in the V2G setting, the battery's charge goes up or down depending on the needs of the grid operator, which sometimes must store surplus power and other times requires extra power to respond to surges in usage. The ability of the V2G car's battery to act like a sponge provides a solution for utilities, which pay millions to generating stations that help balance the grid. Willett Kempton, who began developing the technology more than a decade ago, estimates the value for utilities could be up to $4,000 a year for the service, part of which could be paid to drivers. A car sitting there with a tank of gasoline in it, that's useless," says Kempton. "If it's a battery storing a lot of electricity and a big plug that allows moving power back and forth quickly, then it's valuable.""