A common argument against electric vehicles is that they'll increase demand for carbon-producing electricity and cause brownouts during peak times. But what if plug-ins could actually prevent these outages by sending electricity from their batteries back to the grid?
It's an interesting concept dreamed up by engineers at the University of Technology Sydney. Combining their research on plug-in hybrids and electrical grids, they've developed "Switch," a plug-in Toyota Prius that acts as a sort of an energy reservoir that can give back to the grid whenever needed.
The Switch uses a 4.1 kWh lithium ion battery stored in the trunk to store extra electricity that is theoretically purchased during cheaper off-peak times. The extra battery also helps power the Prius' existing NiMH battery pack and raises fuel economy to 118 mpg.
On the bumper are two outlets--one for charging the battery and one for sending electricity back to the grid, and a grid synchronous inverter --the kind commonly used in solar PV rooftop systems--enables users to send electricity in the second battery back to the grid with the flip of a switch.
Switch Prius owners could be compensated for this energy share, and charging the cars at off-peak time could cost as little as 50 cents a day. In high production volumes, the vehicle-to-grid technology should cost auto makers a few hundred dollars, according to Project Research Consultant Josh Usher.
While the number hasn't been verified by manufacturers, the ability to store extra energy and send it to the grid would offset the cost and need to develop additional power stations.(Source: http://www.wired.com/autopia/2009/05/a-prius-that-gives-back-to-the-grid/)