Compressed air energy storage (CAES) systems are being developed to help electric utilities manage peak energy demands. These systems store energy by compressing air underground, then release it by heating and expanding the air through a turbine-generator setup. CAES plants are being designed, with the first large-scale plant set to be finished in 1977. Based on system specifications, CAES systems seem to be more cost-effective than gas turbines and other storage options for a wide range of fuel and charging power costs.