The present invention provides for the utilization of a cushion gas in compressed air energy storage (CAES). In particular, the use of carbon dioxide (CO.sub.2) as the cushion gas has been provided. Using CO.sub.2 as the cushion gas enhances the effectiveness of the CAES by allowing greater amounts of compressed air to be stored and extracted.
STATEMENT OF GOVERNMENTAL SUPPORT
 The invention described and claimed herein was made in part utilizing funds supplied by the U.S. Department of Energy (DOE) under Contract No. DE-AC02-05CH11231. The government has certain rights in this invention.