The Pacific Northwest May Store Excess Wind Energy in Volcanic Rocks

Too Much Wind Can Throw Off the Grid

by Rebekah Severson, age 15

For thousands of years, we have known the power of winds. In Greek mythology, the demigod Aeolus captured gusting winds in hollowed-out mountains, and released them by stabbing his sword into the earth. Today, scientists harken back to this notion, asking, can we store wind in rock?

Recent research from the Bonneville Power Administration (BPA) and the U.S Department of Energy’s Pacific Northwest National Laboratory suggests excess wind power could be stored for long periods of time, far below the surface of the earth, in porous rock.

America’s Pacific Northwest region is a huge supplier of renewable energy. With strong winds and roaring rivers, Mother Nature gifts this region with abundant sources of natural energy. These energy sources are then harvested with wind turbines and hydroelectric dams. But the region may have too much of a good thing.

With the ever-fluctuating supply of renewable energy sources, like wind and water, surpluses can throw the energy grid off-balance. Some wind farmers have been forced to shut down turbines to cope. They then lose tax credits and millions of dollars in revenue due to decreased production.

A system called Compressed Air Energy Storage (CAES) could be the answer. CAES plants allow surplus wind energy to be pumped underground, stored there, and released when needed. The air is then heated to increase its volume and velocity as it is released aboveground. This way energy suppliers could put surpluses to good use when wind supply is low. CAES is already in use at two different sites. The system has been used in Germany since 1978 and Alabama since 1991. At these sites, CAES stored energy in salt caverns left empty by mining. The study for the Pacific Northwest is examining the possibility of using the same technology as well, but with a twist. Wind energy would be stored in naturally permeable volcanic rocks instead.

“We’re talking about air far below the water table, in the kinds of places where you would find things like fossil fuels,” said Haresh Kamath, the energy storage program manager with the Electric Power Research Institute.

Although this idea isn’t new, its execution is. The two proposed Pacific Northwest sites would require two different approaches. The site north of Boardman, Oregon is located near a natural gas pipeline, which would provide heating for expanding the air’s volume and velocity. The site in Yakima Canyon would incorporate a new design using geothermal energy instead. The energy would not only heat the air but also power a chiller for cooling, making its air compressors run more smoothly.

If putting these porous rocks to use works, excess wind energy could be stored for months. This would be extremely beneficial for energy suppliers like BPA. Even half a day of storage for renewable energy sources can make a difference. Last May, BPA sold power for extremely low rate - less than $1 per megawatt hour.

“We could have sold it for $35 if we could have saved it ‘til the afternoon,” said Steve Knudson, who managed a recent study for BPA.

Storing this power would also be helpful during times when other renewable energy sources are running low, such as during droughts.

“With climate change, if we see dramatic shifts in the amount of rainfall and snowpack, it’s just one more reason to store [wind energy] and have it when we need it,” says Joel Scruggs, a spokesman for BPA.

Because 13% of this region’s power supply comes from wind, adding this flexibility to the energy grid could greatly improve power availability in the Pacific Northwest region.

[Source: National Geographic]