What is the primary benefit of using compressed air energy storage (CAES) in areas with suitable geological formations?

The primary benefit of using compressed air energy storage (CAES) in areas with suitable geological formations, such as underground salt caverns or depleted natural gas reservoirs, is the ability to store large amounts of energy at a relatively low cost compared to other large-scale energy storage technologies. CAES systems compress air using electricity during off-peak hours and store it in these underground formations. During peak demand, the compressed air is released, heated (in diabatic CAES) or not heated (in adiabatic CAES), and then expanded through a turbine to generate electricity. The use of existing geological formations as storage reservoirs significantly reduces the capital cost of CAES, as it eliminates the need to construct expensive above-ground storage tanks. This makes CAES a cost-effective solution for large-scale, long-duration energy storage. Furthermore, the large volume of these underground formations allows for the storage of substantial amounts of compressed air, enabling CAES systems to provide grid-scale energy storage services for extended periods. The geological formations also offer natural insulation, minimizing thermal losses and improving the overall efficiency of the CAES system. However, the availability of suitable geological formations is a key constraint on the deployment of CAES technology.