Compressed air energy storage generation system and power generation method using it

A compressed air storage generating system and a power generating method using the same are provided to keep uniform pressure of discharging air from a storage tank by constituting multiple storage tanks, connecting lower parts of the tanks with each other, and containing water in the tanks. A compressed air storage generating system includes a compressor(20) inhaling and compressing outside air by operation of a motor, a storage tank storing the compressed air, a combustion device(50) burning fuel mixed with the compressed air supplied from the storage tank, a turbine(40) operated by the burned gas, and a generator operated by the turbine. The storage tank, a first storage tank(31) and a second storage tank(32), are connected to each other through a connecting pipe(33). An intake port(311) and a discharge port(312) are formed on a top of the first storage tank to inhale the compressed air from the compressor and to discharge the compressed air in the storage tank. Storage water(34) fills lower parts of the first and the second storage tank to seal the second storage tank hermetically to be used as a pressurizing device.