Alternative Fuel Vehicles Could Boost Grid Services, Wind

By Published On: October 13, 2006

The grid’s ancillary services could benefit from increased use of electric vehicles as well as plug-in hybrids. “Electric vehicles are almost perfect for [ancillary services] because there’s really zero net energy transfer,” said Tom Gage, AC Propulsion president. “It’s just bursts of power in or out.” Electricity made by plants serving the grid and stored in cars is preserved for later grid use with minimal losses, he explained. AC Propulsion, which hand-makes electric cars in San Dimas, has technology that can support so-called V2G – or vehicles to grid – applications, in which electricity stored in vehicles feeds the grid when called on by dispatchers. However, Gage said utility regulations must be changed to enable use of this emerging technology. Deployment of both battery-powered and plug-in hybrids would, at a minimum, be a boon to wind power. “The big plus for wind is having the ability to store the power when it’s generated,” said Dan Santini, Argonne National Laboratory Center for Transportation Research technology analysis section leader. In California and other areas of the nation, wind blows more at night, when power demand is slack. However, it is also the time most cars are parked in garages and could easily be plugged into the grid. The Sacramento Municipal Utility District has worked with Willett Kempton, University of Delaware professor of marine and earth studies, to see how V2G technology could support development of the muni’s wind resources. In a paper presented to the California Air Resources Board at a September 26 meeting, SMUD said it would require 1,950 battery electric vehicles (0.3 percent of cars in the Sacramento region) or 19,500 plug-in hybrid vehicles (3 percent of the area’s cars) to regulate a 39 MW wind installation. Regulation means the vehicles would be called on to manage wind fluctuations and to match ramp rates of gas-fired generators. Storing nighttime wind power – abundant during summer in SMUD’s area – to help meet the next day’s peak would require 15,600 battery electric vehicles or 34,667 plug-in hybrid vehicles. Santini told the ARB that plug-in hybrids would significantly reduce overall greenhouse gas emissions, even if they resulted in increased reliance on coal-powered plants for charging. Lower emissions from hybrids than from gasoline-powered vehicles would more than offset greenhouse gas emission increases at the coal plants, he explained. While V2G is promising, Santini said it will take a long time to develop. He recommended that utilities and automakers should first look at using electricity stored in car batteries to provide household services, including backup power during outages and peak loads on the grid. Plug-in hybrids are more likely to encourage greater use of wind power because of their ability to store wind energy that is now surplus, according to Santini. This would increase revenues to wind generators. AC Propulsion’s battery electric vehicles are seen as a method to provide ancillary services to the grid because they respond to dispatchers in four-second intervals, according to Len Beck, Pepco Holdings senior regulatory affairs analyst. Just 50 of the vehicles could provide the minimum 1 MW block of power purchased for ancillary services by the grid operator PJM in the mid-Atlantic region. With an eye toward offering ancillary services from vehicles, Pepco subsidiary Delmarva Power is pursuing a project with the University of Delaware to develop V2G grid feed-in and dispatch technology. It would start with a couple of AC Propulsion vehicles. Fundamental to the V2G concept is to aggregate car owners and sell the joint ancillary services to regional grid operators, according to Gage. Given the current market for those services, Gage said, aggregators might pay battery electric vehicle owners between $100 and $500 a month for enrolling in a V2G system. The payments would amortize the additional cost of buying an electric vehicle. Batteries represent a major component in the initial price and long-term maintenance cost of electric vehicles. A V2G system requires that plug-in hybrids or battery electric vehicles have onboard controllers that allow power to flow both into and out of the vehicle as needed. It also requires the external capability for power to flow both ways between the cars and the grid and a way to control that flow. Delmarva may use cell phone technology connected to the Internet to control the process, said Beck. – William J. Kelly

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