Electric vehicles (EVs) can reduce our dependence on fossil fuels, but they also put stress on an already overworked electric grid. How can this conflict be reconciled?

Engineers at the National Renewable Energy Laboratory (NREL) are developing smarter electric vehicle charging systems that can talk to the smart grid and determine the best time to charge. Since a vehicle only takes a few hours to fully charge and typically sits idle for much of the day, smart charging vehicles can ease their burden on the grid without causing an inconvenience for the driver.

Even better, it’s possible that EVs can become a source of energy storage on a smart grid. Imagine a fleet of EVs parked and plugged in on a very hot afternoon. Every building is running its air conditioning and the grid is struggling to provide power. A Nissan Leaf’s battery pack, when fully charged, holds about 24kWh of energy. A few thousand EVs, coupled with other smart grid technology, could provide enough energy to eliminate the need to fire up a peak power plant. In places where electric rates are higher during peak hours, you could charge your car overnight when the price is low and sell energy back during the day at a higher rate!

Nissan has developed a Leaf to Home kit that turns the Leaf into a backup power source for a house. Although the kit isn’t yet available in the US, at least one person was able to connect his Leaf to a standard inverter in order to provide emergency power during super-storm Sandy.



Of course that system only had enough energy to power his fridge for a few days, but it’s a start. Utilities are working with EV manufacturers to make it happen on a larger scale.