Re: Storing wind power as compressed air. Interesting idea.
A similar energy storage system has been used with hydro electric dams in California.
I fished a reservoir in California that had a regular hydroelectric dam, and then a second reservoir that was in a higher canyon. During the high demand system, water was released from the upper canyon and the electricity was added to the main dam output.
During the night, water still has to flow from the lower dam to keep the main river flowing but there is not enough demand to use all the electricity. The extra power is used to reverse the water flow and pump water into the upper reservoir.
"Discovery consists of seeing what everybody has seen and thinking what nobody has thought"..........Szent-Gyorgy