Power-generation operators can use compressed air energy storage (CAES) technology for a reliable, cost-effective, and long-duration energy storage solution at grid scale. We. . CAES startups create energy storages using compressed air. Hydrostor is a creator of Advanced Compressed Air Energy Storage (A-CAES) - long-duration, emission-free, economical energy storage. By converting electricity into compressed air during low-demand periods and releasing it when needed, this technology bridges the gap between intermittent renewable sources and stable grid. . 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 compressed air is contained in abandoned salt mines in the Yingcheng area of Hubei, China's sixth most populous province.