ABSTRACT
Compressed air energy storage (CAES) is a process for storing and delivering energy as electricity. A CAES facility consists of an electric generation system and an energy storage system. Off-peak electricity at night from renewable resources or when prices are low is stored as air pressure in a geological air storage vessel. During intermediate- and peak-demand periods, compressed air is released from the pressured energy storage system, heated by combustion of natural gas, and used to drive high-efficiency turbines to produce electricity. Earth-based structures suitable for service as air storage vessels include the following: 1) solution-mined salt cavities; 2) excavated mine cavities; 3) aquifer-water-bearing geologic structures; and 4) depleted natural gas reservoirs.
