Batteries Hold Promise
by Jeremy Fugleberg
CASPER, Wyo. -- A $44 million large-scale battery system proposed for a wind farm in Texas could be a "game-changer" for wind energy, an industry spokesman says.
Yet others in the wind power industry and the natural gas power industry, which provides a lot of fill-in power for wind energy, aren't quite as excited.
The 36-gigawatt battery system -- the largest known system tied to a wind farm -- is slated for installation at the Duke Energy Corp.-owned 153-megawatt Notrees wind project.
Such a system can store energy produced during times of lower electricity consumption and then pump that energy into the grid during peak demand times -- smoothing out the flow of electricity into the grid.
That might prove to be an important innovation for Wyoming, where several companies, including North Carolina-based Duke, are operating and developing wind farms to harness the state's unceasingly world-class winds.
"In places like Wyoming, where the wind often blows strongest at night, technology that stores renewable power and dispatches it during the day -- during periods of peak demand -- could be a real 'game-changer' in the years to come," wrote Duke Energy spokesman Greg Efthimiou in an emailed statement.
But others in the wind power and the natural gas industry aren't quite ready to grant the battery systems such high status just yet.
While there might be situations where battery backup could provide the balance needed for a wind-energy system, it simply can't compare to the reliability of natural gas-fired power plant support, said Chris Hogan, a spokesman for the American Gas Assocation, which represents natural gas utilities.
"If the wind doesn't blow and you turn on a gas plant, you have electricity -- period. It is the ultimate reliability tool," he said in an email. "If the wind doesn't blow for days, or doesn't blow at night or more power is needed than can be delivered by the turbine system, you get power the moment you turn the gas plant, on and it is indifferent to weather or pretty much anything else."
The American Wind Energy Association, a lobbyist for wind energy developers and manufacturers, doesn't comment on specific projects, said spokeswoman Ellen Carey. She referred the Star-Tribune to an association fact sheet on wind power and energy storage.
The fact sheet generally talked down the benefits of energy storage as the most expensive of power-flexibility options available to wind energy developers.
"If a constraint on the transmission grid prevents a wind plant or group of wind plants from selling their full output on a consistent basis, it could be economical to store electricity that would otherwise have been wasted," the fact sheet stated. "However, this type of application is a short-term fix; building out the transmission grid is typically the more optimal long-term solution to a transmission constraint."
Yet this "short-term fix" might get a chance to prove its worth. Beside its battery system bound for Duke's Texas wind farm, battery maker Xtreme Power recently commissioned a 15-megawatt storage system at the 30-megawatt Kahuku wind farm in Hawaii and is providing storage for several U.S solar energy projects.
In both wind power cases, a U.S. Department of Energy grant is helping fund the cost of the projects, including half of the cost at the proposed Duke installation.
Duke says it will work closely in Texas with state electrical grid regulators and independent researchers to integrate the system into the grid, collect data needed to assess the potential for broader use of energy storage at wind farms, and share the data through the Energy Department's Smart Grid Information Clearinghouse.
"Renewable energy is growing more affordable each day," Efthimiou said. "The intent of Duke Energy's large-scale battery storage demonstration project is to increase the reliability of renewable energy, so we can tap into it whenever we need it most -- not just when the wind is blowing or the sun is shining." Duke expects the battery system at the Texas wind farm to begin operation in 2012.
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