Recharging the Grid with Electric Cars

A utility in Delaware has taken a step toward a future in which electric cars store renewable energy to help make its use more widespread. The city of Newark has approved a system called vehicle-to-grid (V2G), in which the battery pack in a car serves as a place to temporarily store energy from the power grid.

A big problem with renewable sources of power like solar or wind is that they only operate intermittently. For now, renewables provide such a small part of the total electricity supply that other sources can easily make up for the hours, minutes, or days when the wind isn't blowing and the sun isn't shining. But if we're ever to rely on them for a large part of our power, we'll need a cheap way to store the energy that they produce for when it's needed most.

The vehicle-to-grid concept suggests a way to store energy cheaply, since the batteries in electric cars have already been paid for. Most of the time, a car is just sitting around doing nothing. For short-term storage--needed to smooth out fluctuations in power from a wind turbine, for example--a utility could quickly charge a car (or, ideally, distribute a little charge to hundreds or thousands of cars) when the wind is blowing and then take that electricity back a few minutes later when the wind dies down. The more cars that are available, the more energy can be stored. Longer-term storage might also be possible: a car owner could charge up for a discount at night, provided she agreed to keep the car plugged in at work to supply extra power during peak power demand in the afternoon.

Of course, there would have to be some sort of agreement so that energy companies couldn't take so much that the driver ends up stranded, and they'd have to recharge a car before the evening commute. But there are even bigger challenges. There simply aren't many electric cars out there right now. Two-way hookups to the grid would also need to be installed, and the grid may have to be upgraded in other ways. And lastly, all the charging and discharging could shorten the lifetime of the battery (not to mention void the warranty from automakers).

There are probably more issues. But what do you think? Is V2G a good idea?