Next spring Xcel Energy Inc., the state of Minnesota and a Virginia-based technology firm will test the first battery in the country capable of storing wind energy.
The breakthrough technology, which is the size of two semitrailer trucks stacked atop each other, was built in Japan and shipped to Luverne, Minn., where it will store electricity generated by the nearby Minwind Energy wind turbines. S&C Electric Co. expects the equipment will be completely installed by April.
The battery consists of a score of 50-kilowatt modules. When it is fully charged, the massive sodium-sulfur battery -- which weighs about 80 tons -- can store 7.2 megawatt-hours of electricity. That's enough to power 500 homes for about seven hours. It will cost more than $5.4 million to buy and install the battery and analyze its performance.
The technology could help allay critics of wind energy, who lament that no electricity is produced when there's no wind. If successful, the battery will store wind energy and release its power onto the electrical grid when the air is still.
"Energy storage is key to expanding the use of renewable energy," Xcel Chairman and CEO Dick Kelly said. "This technology has the potential to reduce the impact caused by the variability and limited predictability of wind-energy generation."
Xcel, which invested $3.6 million in the project, expects the battery "to become very important to both us and our customers," Kelly said.
Xcel, the largest wind-energy producer in the country, is working to make it easier to integrate renewable energy onto the electrical grid as part of its "Smart Grid" strategy. It has a mandate to generate 30 percent of all its energy from renewable sources by 2020.
Xcel bought the battery from Japan's NGK Insulators Ltd. The batteries are used in Japan to store wind energy, and are used in a few nonwind applications in the United States.
