Second generation compressed air energy storage system

Abstract

A method includes an air storage (18), a compressor (20) supplying compressed air to the air storage, a power generating structure (11, 102), a heat exchanger (24), an auxiliary combustor (27), an air expander (30), and an electric generator (32). The system operates in one of modes a) a main power production mode wherein the auxiliary combustor is inoperable and the power generating structure is operable, to produce power by the air expander, fed by the heated compressed air received from the air storage, in addition to power produced by the power generating structure, or b) a synchronous reserve power mode wherein the auxiliary combustor is operable and the power generating structure is inoperable, with compressed air withdrawn from the air storage being preheated by the auxiliary combustor that feeds the air expander, with the air expander expanding the heated air and the generator providing immediate start-up power.