Overview of compressed air energy storage Compressed air energy storage (CAES) is the use of compressed air to store energy for use at a later time when required , , , , . Excess energy generated from renewable energy sources when demand is low can be stored with the application of this technology.
The number of sites available for compressed air energy storage is higher compared to those of pumped hydro [, ]. Porous rocks and cavern reservoirs are also ideal storage sites for CAES. Gas storage locations are capable of being used as sites for storage of compressed air .
They developed a novel energy storage system which stores excessive energy in the form of compressed air and thermal heat. The cooling power from this system was generated by direct expansion of compressed air instead of the use of absorption chilling technology.
Appendix B presents an overview of the theoretical background on compressed air energy storage. Most compressed air energy storage systems addressed in literature are large-scale systems of above 100 MW which most of the time use depleted mines as the cavity to store the high pressure fluid.
Analysis of compressed air energy storage systems is usually conducted by taking both compression and expansion stages into consideration using ideal gas laws. Expanders’ mechanical work is first transformed.
There are several compression and expansion stages: from the charging, to the discharging phases of the storage system. Research has shown that isentropic efficiency for compressors as well as expanders are key determinants of the overall characteristics and efficiency of compressed air energy storage systems .