Compressed Air Energy
Storage (CAES) is an energy storage system in which air is compressed at high pressure and stored in large underground cavities. The compressed air is passed through turbines to recover energy. Compressed air storage uses off-peak electrical energy to compress air into underground storage tanks that are stored until times of peak or intermediate power demand. Wind power provides a good way to charge CAES storage. In the absence of wind or solar radiation, compressed air storage can provide energy balancing. Storage is typically underground in natural aquifers, depleted oil or gas fields, mined salt caverns, excavated or in natural rock caverns. They can have huge volumes and can bridge an extended renewable energy outage.
Theuse of earth cavities as compressed air storage is extremely economical and can be flexibly adapted to demand.
To generate electricity, the compressed air is first heated by gas burners and then passed through a turbine.