A power generation system comprising: a first compressor configured to compress air to a first pressure via a first rotational power; a second compressor configured to compress air to a second pressure via a second rotational power, wherein the second pressure is greater than the first pressure; a combustor configured to receive the compressed air from the second compressor and combust a flammable fluid therewith to produce an exhaust stream; a first turbine configured to: receive the exhaust stream from the combustor; generate the second rotational power from the exhaust stream; output the second rotational power to the second compressor; and output the exhaust stream; a power turbine configured to: receive the exhaust stream from the first turbine; and generate a third rotational power therefrom; a coupling device configured to couple the first compressor to a second turbine and to decouple the first compressor from the second turbine; an electrical generator coupled to an output of the power turbine and configured to output a first electrical power from the third rotational power; and a controller configured to: cause the coupling device to mechanically decouple the second turbine from the first compressor in a first operating mode; and cause a valve to open to direct compressed air from an air storage cavern to an inlet of the second compressor during the first operating mode. a first compressor configured to compress air to a first pressure via a first rotational power; a second compressor configured to compress air to a second pressure via a second rotational power, wherein the second pressure is greater than the first pressure; a combustor configured to receive the compressed air from the second compressor and combust a flammable fluid therewith to produce an exhaust stream; a first turbine configured to: receive the exhaust stream from the combustor; generate the second rotational power from the exhaust stream; output the second rotational power to the second compressor; and output the exhaust stream; receive the exhaust stream from the combustor; generate the second rotational power from the exhaust stream; output the second rotational power to the second compressor; and output the exhaust stream; a power turbine configured to: receive the exhaust stream from the first turbine; and generate a third rotational power therefrom; receive the exhaust stream from the first turbine; and generate a third rotational power therefrom; a coupling device configured to couple the first compressor to a second turbine and to decouple the first compressor from the second turbine; an electrical generator coupled to an output of the power turbine and configured to output a first electrical power from the third rotational power; and a controller configured to: cause the coupling device to mechanically decouple the second turbine from the first compressor in a first operating mode; and cause a valve to open to direct compressed air from an air storage cavern to an inlet of the second compressor during the first operating mode. cause the coupling device to mechanically decouple the second turbine from the first compressor in a first operating mode; and cause a valve to open to direct compressed air from an air storage cavern to an inlet of the second compressor during the first operating mode.