A power generation system includes a first compressor, a second compressor, a combustor configured to receive compressed air from the second compressor to produce an exhaust stream, a first turbine, and a power turbine. The first turbine is configured to receive the exhaust stream, generate a rotational power from the exhaust stream, output the rotational power to a second compressor, and output the exhaust stream. The system includes a coupling device configured to couple and decouple the first compressor to/from a second turbine, an electrical generator coupled to an output of the power turbine and configured to output electrical power, and a controller configured to cause the coupling device to mechanically decouple the second turbine from the first compressor, and cause the coupling device to direct compressed air from an air storage cavern to an inlet of the second compressor.