A review on underwater compressed air energy storage

Underwater compressed air energy storage (UCAES) uses the hydrostatic pressure of water to realize isobaric storage of the compressed air. The advantages of such a method include high efficiency, reduced topographical limitations, and flexibility in storage scale, providing a potentially suitable technology for storing offshore renewable energy. In this paper, a brief review is given first on emerging compressed air energy storage technologies, the focus is the on the UCAES. We introduce the working principle and current state of research in the UCAES. We also perform an analyses on the technology particularly UCAES combined with the use of a flexible energy bag. Finally, key future technology developments and outlook of the UCAES are summarized.