Compressed air energy storage (CAES): current status, geomechanical aspects and future opportunities

Abstract

Abstract A compressed air energy storage (CAES) facility provides value by supporting the reliability of the energy grid through its ability to repeatedly store and dispatch energy on demand. Two main advantages of CAES are its ability to provide grid-scale energy storage and its utilization of compressed air, which yields a low environmental burden, being neither toxic nor flammable. The focus of this review paper is to deliver a general overview of current CAES technology (diabatic, adiabatic and isothermal CAES), storage requirements, site selection and design constraints. We discuss underground storage options suitable for CAES, including submerged bladders, underground mines, salt caverns, porous aquifers, depleted reservoirs, cased wellbores and surface pressure vessels. A geomechanical perspective is provided regarding the pressure limits for these options. The impacts of cyclic injection and withdrawal of compressed air, and the importance of caprock assessments with porous rock CAES, are also discussed. In addition, we provide an overview of the large-scale CAES facilities that are currently active or under development and a cost comparison of the diabatic, adiabatic and isothermal CAES options. Lastly, we outline major challenges and future opportunities for CAES and the top priorities for research, industry and stakeholders.