14 - Compressed-Air Energy Storage

Abstract

Compressed-air energy storage (CAES) plants operate by using motors to drive compressors, which compress air to be stored in suitable storage vessels. The energy stored in the compressed air can be released to drive an expander, which in turn drives a generator to produce electricity. Compared with other energy storage (ES) technologies, CAES plants have a very large power rating and storage capacity, low self-discharge, and a long lifetime. These attributes make it the most promising and cost-effective method for bulk ES grid services. Conventional CAES plants have a relatively low roundtrip efficiency; however, research studies into more advanced CAES concepts, such as adiabatic and isothermal CAES, seek to improve this. The world has a large capacity for storing compressed air underground, meaning that CAES could provide a significant amount of the world's future ES needs. This chapter gives the working principals of CAES, compares CAES with other ES technologies, lists the grid services that CAES is most suited to, introduces advanced CAES designs and current projects, examines the exergy analysis of CAES plants and components, reports the global potential for CAES, and offers future research directions and challenges.