This paper provides a comprehensive overview of CAES technologies, examining their fundamental principles, technological variants, application scenarios, and gas storage facilities. . This technology strategy assessment on compressed air energy storage (CAES), released as part of the Long-Duration Storage Shot, contains the findings from the Storage Innovations (SI) 2030 strategic initiative. The objective of SI 2030 is to develop specific and quantifiable research, development. . Compressed air energy storage (CAES) is a promising solution for large-scale, long-duration energy storage with competitive economics. Optimizing the efficient cascading utilization of multi-grade heat can greatly improve the efficiency and overall system performance. Particularly, the number of compressor and. . Compressed Air Energy Storage (CAES) has emerged as one of the most promising large-scale energy storage technologies for balancing electricity supply and demand in modern power grids. Renewable energy sources such as wind and solar power, despite their many benefits, are inherently intermittent. . As a mechanical energy storage system, CAES has demonstrated its clear potential amongst all energy storage systems in terms of clean storage medium, high lifetime scalability, low self-discharge, long discharge times, relatively low capital costs, and high durability. However, its main drawbacks. .