For 25 years, the cooperative has mastered the art and science of compressing air, storing it in a salt cavern beneath the earth, and using it to produce electricity.

At night, while you sleep and your appliances rest, the plant uses excess electricity from the grid to compress air and pump it underground into an airtight salt cavern.

A salt cavern facility may occupy only one one-hundredth of the area taken up by a depleted gas reservoir facility.

The walls of a salt cavern are strong and impervious to gas over the lifespan of the storage facility.

There are three principal types -- depleted gas reservoirs, aquifer reservoirs and salt cavern reservoirs.