Salt caverns in the energy transition: A comparative review of cavern integrity from strategic reserves to high-frequency cyclic storage

The global energy transition, driven by the imperative to ensure energy security while achieving deep decarbonization, depends critically on the deployment of large-scale, long-duration energy storage. Solution-mined salt caverns constitute a well-established geological medium for subsurface energy storage. However, adapting these underground structures from traditional, quasi-static hydrocarbon storage to next-generation, high-frequency energy applications introduces complex, coupled thermo-hydro-mechanical-chemical (THMC) challenges. This paper comprehensively reviews the geomechanical viability and operational integrity of salt caverns across a diverse spectrum of applications, including strategic petroleum reserves (SPRs), natural gas storage (NGS), underground hydrogen storage (UHS), and compressed air energy storage (CAES). Key THMC processes intrinsic to each storage modality are examined, ranging from thermal fatigue in CAES to microbially induced corrosion in UHS. Specifically, the review systematically analyzes the path-dependent behavior of rock salt by comparing the quasi-static loading of strategic reserves, which potentially promotes the self-healing of the rock mass, with the high-frequency pressure and thermal cycling inherent to grid-balancing applications, which may induce irreversible fatigue damage and associated degradation of cavern sealing capacity. This review aims to facilitate the safe deployment of salt cavern storage by providing fundamental insights into safety assessment and operational design, thereby supporting a decarbonized global energy system.