Introduction  Compressed air energy storage (CAES), as a long-term energy storage, has the advantages of large-scale energy storage capacity, higher safety, longer service life, economic and environmental protection, and shorter construction cycle, making it a future energy storage technology comparable to pumped storage and becoming a key direction for future energy storage layout. By summarizing the current status of CAES technology, the working principles, challenges, and solutions of different CAES technologies are analyzed, which is provided for the development of CAES technology through research.

  Method  Firstly, the principle of CAES was introduced, the key equipment, such as compressors, turbo-expanders, and heat exchangers, was analyzed, and the key equipment suitable for the CAES was proposed. Then, the commonly used key technologies, development trends, and engineering cases of large-scale CAES were introduced from the perspective of ground key process technologies and underground gas storage facilities. Finally, the future development trend of CAES technology was analyzed.

  Result  The results show that regenerative CAES is currently the mainstream technology in China, and high-temperature heat storage has become the future development direction of CAES, and is also an important way to improve the efficiency of CAES. At the same time, there is still room for improvement in key equipment and technology optimization, cost reduction, and application scenario development of the system.

  Conclusions  CAES, as a long-term energy storage method, plays an important supporting role in the construction of future new power systems.