Compressed air energy storage has been used for decades, but only at two facilities in Germany and Alabama, built before solar and wind started creating challenges for power grid operators. “This is a pretty simple concept,” said Bobby Bailie, director of business development for energy storage at the German industrial firm Siemens. “You’re pushing air into a cavern, storing that energy. And at times when you need it, you pull it back out.” — The Los Angeles Times

Can a giant underground salt cave in the Utah desert hold a potential answer to Los Angeles’s growing sustainable energy needs?

The Los Angeles Times digs into a new-old approach for storing energy in compressed air deposits deep underground. The compressed air, generated with the help of solar or wind energy, is held deep below the surface of the earth until needed, creating a giant, high-pressure battery.

When the energy is required, say on a cloudy day when solar generation might dip, the compressed air is used to turn a second set of turbines that recaptures the air’s energy, thus converting the air into electricity.