Images: Making wind power that lasts all day

One of two oft-cited examples of compressed air energy storage is in McIntosh, Ala., where a facility has been operating since 1991. According to its developers, the system of compressing air during off-peak hours and pulling it out when needed to run a gas turbine reduces fuel consumption by 25 percent.

This illustration shows the various components needed for CAES, including a limestone cavern.

Photo by CAES Development Company