In an attempt to save us from carbon dioxide, Minnesota utility hauls in 3.2 million pounds of Japanese batteries

Xcel looks to store excess wind energy in giant batteries - TwinCities.com

The Minneapolis-based utility is under a state mandate to produce 30 percent of its electricity from clean renewable resources like wind by 2020, and it has been testing the massive batteries to determine whether they will allow Xcel to capture more wind power. A lot of that electricity is dumped when there is no demand for it at night.

The utility trucked in 20 80-ton sodium-sulfur batteries it bought in Japan and created a 1-megawatt battery-storage technology project.
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But don't expect to see giant batteries parked next to wind farms any time soon. The technology is still too expensive, Novachek said.

Xcel's batteries cost more than $4 million and they were partially offset by a $1 million grant from Xcel Energy's Renewable Development Fund.