Compressed Air Energy Storage (CAES)

From Open Energy Information


Compressed air energy storage (CAES) is a way to store energy that is generated at night and deliver the energy during the day to meet peak demand. This is performed by compressing air and storing it during periods of excess electricity and expanding the air through a turbine when electricity is needed.

Technology Description

Diabatic compressed air energy storage is what the two existing compressed air energy storage facilities currently employ. This method is essentially the same thing as a conventional gas turbine except that the compression stage and the expansion stage occur at different time periods. For example, when electricity is in excesses, air is compressed and stored in a reservoir, then when electricity is needed, air is heated with natural gas and expanded through a turbine.
Adiabatic compressed air energy storage is system in which the heat created due to the compressing of air is captured via a thermal energy storage system. When the electricity is needed, this stored heat is returned to the air before expansion through the turbine. This method does not require the use of premium fuels in order to heat the compressed air before expansion as the diabatic method requires.

Storage options include above ground pressure vessels and below ground geologic formations such as salt caverns.


  • McIntosh, Al
  • Huntorf, Germany