Compressed air energy storage refers to an energy storage method that uses electrical energy to compress air during periods of low grid load and releases the compressed air to drive a steam turbine to generate electricity during periods of high grid load. The main types include traditional compressed air energy storage systems, compressed air energy storage systems with thermal storage devices, and liquid-gas compressed air energy storage systems.
There are many different types of compressed air energy storage systems. They can be classified according to the working medium, storage medium, and heat source: traditional compressed air energy storage systems (which require fossil fuel combustion), compressed air energy storage systems with heat storage devices, and liquid-gas compressed energy storage systems.
Compressed air energy storage technology is a technology that uses compressed air to store energy. Currently, compressed air energy storage technology is considered the second most suitable technology for large-scale power storage at the GW level, after pumped hydro storage.
The working principle of compressed air energy storage is as follows: during off-peak hours, electricity is used to compress air to high pressure and store it in a cave or pressure vessel, so that the electrical energy is converted into the internal energy of the air and stored; during peak hours, the high-pressure air is released from the storage chamber and enters the combustion chamber for combustion. After being heated by fuel combustion, the air drives the turbine to generate electricity.
Currently, compressed air systems face numerous problems, the most significant of which, like pumped-storage hydroelectric systems, is heavily constrained by geographical conditions. Constructing a compressed air system requires specific geographical locations to serve as large air storage chambers, such as airtight rock caves, salt caverns, or abandoned mines. This limitation is a major factor hindering the widespread adoption of this technology. Furthermore, traditional air compression systems have an efficiency of only 40%-55%, significantly lower than the 80% efficiency of pumped-storage hydroelectric systems.
