Panelists debate the impact of electric cars on the grid

As hybrid and electric vehicles become more common, questions are swirling about whether the electricity grid can handle the resulting new demand for power.

The grid should hold up to the challenge at least in the short term,  industry representatives and regulatory members said at a panel discussion in Washington, hosted by the liberal policy group NDN and its sister group, the New Policy Institute. The panel’s comments came one day after a Massachusetts Institute of Technology report raised concerns about the current grid’s ability to handle a growth in renewable power and electric and hybrid vehicles.

“I think more of the load growth in near term will be driven by households adding another flat-screen TV,” said Kyle Davis, director of congressional relations at MidAmerican Energy Holdings Co.

The addition of 10 million Chevy Volts, the company’s plug-in hybrid electric vehicle, would increase “load” — the rough equivalent of electricity demand — by less than 1 percent, said Mary Beth Stanek, the General Motors Co. director of federal environmental and energy regulatory affairs.

The longer term future of the electric grid poses some challenges and less certainty, the panelists said. Some kinds of hybrid and electric vehicles plug into the grid, while others don’t. Not only that but certain types of plug-in vehicle chargers pull more power from the grid at once than others.

The most common current charging systems — 120 volts and 240 volts — require hours to charge today’s vehicles and generally won’t pose problems to distribution systems, which move  power from the bulk power grid to homes and businesses, Davis said. The challenge comes with even more power-intensive systems that can charge within half an hour, he said.

“We’re telling those who want to pursue that business of 15-to-20-minute charging, you have to talk to utility before you even draw up engineering diagrams for that kind of equipment,” Davis said.

One way to reduce any likely stress electric vehicles could pose to the grid is with “vehicle-to-grid” technology that would let them transfer power to the grid. The panelists indicated the idea holds promise for working with a new generation of “smart grid” technologies that can help the power system adapt to consumer behavior — especially the inevitable practice of en-masse charging after drivers return home from work.

Vehicle-to-grid is promising but is still years away, said Barbara Bauman Tyran, director of Washington and state relations at the Electric Power Research Institute, a research group funded by electric power companies. Whatever the future holds, Tyran said the grid has handled whatever challenges thrown its way in the past.

“Each time the electric utility industry has learned to adapt through technology it has produced to be able to fit that and accommodate it,” she said.

Panelists also mentioned other possible future technologies:

  • Stanek said hydrogen fuel cells, though a long way from commercialization, could give vehicles a range of several hundred miles.
  • Tyran said lithium-air batteries hold the promise of boosting electric-vehicle mileage roughly 10-fold over typical levels in lithium-ion batteries today. Lithium-ion batteries are used in the Chevy Volt, the Nissan Leaf and Toyota Prius, with the Leaf’s roughly 100 miles per charge topping out the list.
  • What happens when electric vehicle batteries meet the end of their useful lives? The panelists suggested using them to store power generated from intermittent renewable sources such as wind and solar.