Midwest utilities seek to ’store’ wind power in aquifer

Wind power is clean and renewable. Now a group of utilities in Iowa, Minnesota and the Dakotas has a plan to make it reliable.
Using existing technology, backers plan to spend $200 million for a “wind storage” project that would be under construction in 2009 and in service in 2011.

Three thousand feet below the surface, a sandstone aquifer (caverns that now hold water) will be injected with pressurized air, temporarily displacing some of the water. The electricity from wind turbines will power the compressors. A pipe will deliver underground air compressed to 900 to 1,000 pounds per square inch. The compression of millions of cubic feet of air will be scheduled for nights and weekends, when wind power often sells for next to nothing.

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