vehicle-to-grid

What will happen when millions of electric vehicles plug into the grid at at the same time? If ZigBee Alliance's blueprints for the SmartGrid go according to plan, not much.

The ugly specter of mass blackouts caused by hoards of EVs rolling into garages and plugging in at the same time is just one of the many arguments EV detractors use against electric vehicles and plug-ins. But EV adoption is inevitable, and the smart grid should make sure that energy loads will be balanced and shifted as needed to recharge them without causing widespread power failure. And eventually, ZigBee predicts, electric cars and plug-ins will become part of the energy solution supplying power to the grid.

But let's back up.

If you haven't heard of the ZigBee Alliance, you're not alone. Before I started this article, I'd never heard of it until I was forwarded one of its press releases. Named after a little-known Nordic elf that has nothing to do with wireless networks or energy, the ZigBee is a standard for wireless sensor networks on which the Smart Grid operates. "And the domain name was available," says Bob Heile, who is chairman of the curiously named group and one of the founders of 802.11.

More than 300 metering, computer, chip processing, electronics, and automotive companies are members the ZigBee Alliance. By incorporating ZigBee's technology in their products, many of these companies are laying the infrastructure that will enable utility companies, networked homes and buildings, and appliances to communicate wirelessly and automate metering as part of the smart grid. That includes electric vehicles.

Electric and plug-in vehicles will undoubtedly be a significant drain on the smart grid--each plugged-in EV has the equivalent drain of another house for hours at a time. But they're also uniquely designed to be able to give back.

"They are essentially batteries with wheels," says Heile. "Ultimately, long after the EV infrastructure is in place and consumers adopt them, there will be opportunities to load shift."

This means that at peak hours people can sell the energy stored in EV batteries back to utility companies. But don't think you can offset the cost of a new Nissan Leaf or Chevrolet Volt by becoming a homespun energy trader of sorts--that technology is still years away.

The typical EV and smart meter rhetoric goes something like, "You can charge your car overnight when electricity rates are cheaper." But the technology isn't entirely there to support that rational. Right now if you don't own a smart meter (you would know if you do) and you plug an EV into an outlet, it doesn't know what the device is or who it belongs to, or when to charge it other than right now. But in the future, it will know who you are by the car you drive so that when you charge at a friend's house, you'll get the bill. Or so the theory goes. … Read more