Friday, April 6, 2012

Air Power to Air Batteries: How Giant Caves Can Store Our Excess Energy - Tested

Compressed air energy storage isn't a new concept, but it warrants reexamination if we're going to rely more on renewable energy production.
Norman Chan
When we drove to Las Vegas for CES this January, Will made a big deal of calling out the massive wind farm along the Tehachapi Pass. It's one of the three major wind farms in California, and seeing a massive army of uniform wind turbines on the side of the hill is a beautiful sight to behold. But anyone who's driven by a wind farm will notice that not every turbine is turning, even on an especially windy day. Some of the turbines may be broken--and they're reported very expensive to repair--but the more likely reason that only a portion of them are activated is that the electrical grid just doesn't need that extra energy at the moment. In fact, the grid that powers our nation rarely ever needs extraenergy, and that's because it operates on an on-demand infrastructure. Controllers carefully predict how much power the country needs to consume at any given moment, and adjust supply from sources like coal and natural gas power plants to feed that demand. It's kind of like an ultra-efficient supply chain for consumer electronics, except that the US doesn't have storage for extra unused power like the Apple store does for unsold iPods. The problem is that we just don't have the battery technology to store energy on that kind of scale, efficiently.
Maggie Koerth-Baker, the writer of a new book called Before The Lights Go Out, wrote about one of the ways we could store excess power generated from wind farms and other renewable (and unpredictable) sources without buying million-dollar chemical batteries from overseas. Compressed Air Energy Storage (CAES) is the idea of using excess power to run air compressors, storing energy in the form of compressed air in, well...airtight caves. Porous rocks can hold a lot of pressurized gas, which would be released to run generators when that energy is needed. Mother Earth to the rescue, once again.
Unfortunately, governments and private companies haven't been in a rush to fund CAES facilities, but Koerth-Baker does name one company in Texas that is literally breaking ground on a CAES system soon. And the types of caverns being surveyed for CAES sites aren't the same ones that you'll find on a camping trip, so don't expect your favorite spelunking site to be retrofitted into a giant battery anytime soon.

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