Monday, 8 July 2013

Compressed air technology to store wind energy
24 May 2013

Renewable energy storage is one step closer becoming a reality in the Northwest. Researchers are proposing a new system that could store enough wind power to power 80,000 homes for a month. But researchers aren't proposing fields lined with batteries. They're using some of the Columbia River Basin's natural geography and compressed air.

If Northwest states are to meet renewable energy goals, they'll need to find a way to store power. Wind and solar vary with the weather. Most of the region's wind power kicks up at the same time as hydroelectric. That can produce more energy than the power grid can handle.

"Without a storage technology, that energy is going to be wasted", McGrail says. "Right now we don't have anything to do with it. We either have to shut down the wind farms or spill excess water over the dams".

Now, researchers have found a way to capture extra energy and store it until people need it. This technology would divert that wind-power to machines that compress air. Next, that compressed air would be pumped thousands of feet underground into airtight cavities in the earth's basalt subsurface.

When people needed more power in the summer or winter, a valve would release the compressed air. That would spin turbines and create energy. Steve Knudsen is with Bonneville Power Administration. He says more storage could help balance power on the grid. "You shouldn't ever have to curtail the generation out of wind plants", Knudsen says.

Alabama and Germany already use this technology. But the amount of power stored at those sites is a drop in the bucket compared to what these researchers are proposing. They say they could store enough energy to power 80,000 homes for a month.

Researchers have picked out two sites that will work well-both in Central Washington. BPA says the next step is for utilities to test the technology on a smaller scale.