A hybrid compressed air energy storage system is provided. A heat exchanger 114 extracts thermal energy from a compressed air to generate a cooled compressed air stored in an air storage reservoir 120, e.g., a cavern. A heat exchanger 124 transfers thermal energy stored in a thermal storage device 130 to compressed air conveyed from reservoir 120 to generate a heated compressed air. An expander 140 is solely responsive (no heat is introduced by way of a combustor) to the heated compressed air to produce power and generate an expanded air. Expander 140 being solely responsive to heated compressed air by heat exchanger 124 is effective to reduce a temperature of the expanded air by expander 140, and thus a transfer of thermal energy from an expanded exhaust gas received by a recuperator 146 (used to heat the expanded air by the first expander) is effective for reducing waste of thermal energy in exhaust gas cooled by recuperator 146.