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A new study by the Department of Energy’s Pacific Northwest National Laboratory and Bonneville Power Administration finds that two underground sites in the Pacific Northwest are ideal for storing energy produced by the wind. Compressed air energy storage plants could capture the wind during times when breezes are more abundant at night and demand for electricity is low for use during peak hours. Able to switch between power storage and generation in a matter of minutes, the method could be an important means to assist states reach their Renewable Portfolio Standards.
Compressed energy storage plants function by using electricity when power is most available to operate air compressors to move pressurized air into a geological storage area. When demand for power is high, the air is released back up to the surface where it is heated and pushed through turbines to create electricity. Many of these plants can re-generate 80% of the electricity they capture. Only two currently exist in the world, and are located in Germany and Alabama and use man-made salt caverns to hold electricity. The PNNL-BPA study looked at porous rock in the Pacific Northwest as a possible alternative to the caverns. They identified two different methods tailored to two specific sites.
The first, called Columbia Hills Site is situated north of Boardman, Oregon. This location would take advantage of a nearby natural gas pipeline to heat the air allowed back to the surface, generating twice the power of a traditional natural gas plant. The second, known as the Yakima Minerals Site in Washington, has no access to a natural gas resource, so the facility would use geothermal heat to operate a chiller that would cool the air compressors as well as reheat the stored air.
Seeing as 13 percent of the Northwest’s electricity comes from wind, the new technology could be a valuable method to storing energy and making renewable more viable. Since the facilities can hold energy for long periods of time, they would be able to capture electricity supplies during the spring in the Northwest when there is more wind and hydroelectric power than the existing infrastructure can absorb. The BPA is currently working with the Northwest Power and Conservation Council to investigate the feasibility of constructing the plants.