Charge \'sharing\' by electric cars could ease strain on power grid

While electric vehicles are good in terms of reduced oil consumption and air pollution they may strain an aging U.S. electrical infrastructure, researchers say. As more and more Americans opt for plug-in electric cars -- more than 96,000 were sold in the United States in 2013 -- the growing fleet will put a lot of new strain on the nation's aging electrical distribution systems like transformers and underground cables, especially at times of peak demand, researchers at the University of Vermont said. How to accommodate all those cars seeking a socket at the same time -- in preparation for the morning rush hour to work, for example -- without crashing the grid or pushing rates to the roof has some utilities concerned, but the researchers say they have a novel solution. "The key to our approach is to break up the request for power from each car into multiple small chunks -- into packets," Vermont engineering and mathematical sciences Professor Jeff Frolik said. By using the nation's growing number of "smart meters" -- household electric meters that communicate information back and forth between a house and the utility -- the new approach would let a car charge for, say, five or ten minutes at a time, then it would "get back into the line," Frolik says, and make another request for power. If demand was low, it would continue charging, but if it was high, the car would have to wait. That would allow electric utilities to spread out the demand from plug-in cars over the whole day and night, the researchers said. "The vehicle doesn't care," study co-author and power system expert Paul Hines said. "And, most of the time, as long as people get charged by morning, they won't care either. "By charging cars in this way, it's really easy to let everybody share the capacity that is available on the grid."