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.
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 . Compressed air energy storage systems are sub divided into three categories: diabatic CAES systems, adiabatic CAES systems and isothermal CAES systems.
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 .
The compressed air storages built above the ground are designed from steel. These types of storage systems can be installed everywhere, and they also tend to produce a higher energy density. The initial capital cost for above- the-ground storage systems are very high.
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 .
In thermo-mechanical energy storage systems like compressed air energy storage (CAES), energy is stored as compressed air in a reservoir during off-peak periods, while it is used on demand during peak periods to generate power with a turbo-generator system.