Methods and associated systems for storing compressed air and extracting energy from the compressed air are disclosed. An exemplary method comprises: compressing air; storing the compressed air in a first storage tank at a first pressure; transferring the compressed air from the first storage tank to a second storage tank; storing the compressed air in the second storage tank at a second pressure lower than the first pressure; discharging the compressed air from the second storage tank; and extracting energy from the compressed air discharged from the second storage tank. The method may also comprise adding heat to the compressed air between the first storage tank and the second storage tank.