Compressed air energy storage
uses pressurized air as the energy storage medium. An electric motor-driven
compressor is used to pressurize the storage reservoir using off-peak energy and
air is released from the reservoir through a turbine during on-peak hours to
produce energy. The turbine is essentially a modified turbine that can also be
fired with natural gas or distillate fuel.
Ideal locations for large
compressed air energy storage reservoirs are aquifers, conventional mines in hard
rock, and hydraulically mined salt caverns. Air can be stored in pressurized tanks
for small systems.