Roland Piquepaille writes: "Scientific American reports that Xcel Energy, a Minneapolis-based utility company, has started to test a new technology to store wind energy in batteries. The company is currently trying it in a 1,100 megawatts facility of wind turbines in Southern Minnesota. The company started this effort because 'the wind doesn't always blow and, even worse, it often blows strongest when people aren't using much electricity, like late at night.' It has received a $1 million grant from Minnesota's Renewable Development Fund and the energy plant should be operational in the first quarter of 2009. And if this project is successful, the utility expects to deploy many more energy plants before 2020 to avoid more polluting energy sources. Read more for additional details and pictures of the batteries used to store wind energy."