How enormous batteries could safeguard the power grid

Until recently, relatively little funding has flowed to grid-storage development. In 2007, the industry overall spent a relatively tiny $2 billion on energy storage at the utility level, according to a report last year by Climate Change Business Journal. That’s starting to change.

Before the recent financial crisis, venture investing in utility-energy storage had risen from about $300 million in 2004 to nearly $700 million in 2007, according to Lux Research, a market research company.

“It’s still an incredibly hot market right now,” says Brad Roberts, chairman of the Electricity Storage Association, a trade group in Morgan Hill, Calif. He expects at least $200 million in new federal funding to accelerate development that languished with just $4 million to $10 million annually over the last 10 years.

Individual companies are accelerating their work, he says. They include A123, a company now producing lithium-ion batteries on trailers to supply ancillary power to utilities, as well as Beacon Power, another Massachusetts company developing flywheel-based systems to store grid power, he says. The big utility American Electrical Power has deployed a sodium-sulfur battery system, too.

A few researchers and utility executives are also creating and deploying some of the world’s most powerful batteries and other grid-backup systems to pick up the slack when energy generated by wind or solar wanes.

“What I’m talking about are batteries the size of a double-decker bus,” says David Bradwell, a battery expert working on grid-scale batteries with new chemistries at the Massachusetts Institute of Technology. While sodium-sulfur is a proven technology, it is still too expensive for mass power storage at around $400 per kilowatt hour, experts say. Mr. Bradwell hopes to get costs down to about $100.

“These batteries could be deployed in a large-scale system over several square miles – or individually, maybe at the base of a wind turbine or at a wind farm,” he says.

A working prototype in Minnesota
Dr. Smyrl, federal researchers, and utility executives are looking at the same renewable storage problem in Luverne, Minn., where the nation’s first wind-to-battery setup is using a small wind farm to charge batteries that release that power onto the grid.

These aren’t your ordinary flashlight batteries – but rather high-temperature, sodium-sulfur batteries the size of two semi-trailers that soak up 7.2 megawatt hours of power generated from seven nearby wind turbines owned by MinWind, a Minnesota wind-power developer.

Overseeing the project is Xcel Energy, the big Minneapolis-based utility that bought the battery from NGK Insulators, a Japanese battery supplier. Smyrl and the others are focused on how much power the sodium-sulfur system can absorb, how quickly, at what cost – and then deliver it to the grid.

Xcel’s interest is much more than academic. Wind power already accounts for 6 percent of the power flowing on its system. A year ago, Xcel’s wind capacity was at 2,700 megawatts compared with about 3,000 megawatts today – it hopes to double that amount by 2020.

Congress is also widely expected to pass legislation requiring utilities to derive perhaps 20 percent of their power from renewable sources by 2021. Even without federal legislation, however, state mandates in nearly half of the states already require a significant percentage of renewable power. In Minnesota, where Xcel sells a lot of power, the state’s renewable portfolio standard calls for 25 percent renewable power by 2025.

“The direction we’re heading [with the battery test] is to meet these state mandates and hopefully going beyond them,” says Frank Novachek, Xcel’s director of corporate planning. “This will help put us in a very good position to meet whatever happens on a federal basis.”

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