Design principles for key operational parameters of salt cavern hydrogen storage

Salt cavern hydrogen storage (SCHS) is a pivotal technology for achieving large-scale, long-term hydrogen energy storage. The operational performance and safety of such facilities are contingent upon the rational design and coordinated optimisation of key operational parameters. This paper systematically reviews the current research status of operational parameters for SCHS. Focusing on core parameters such as operating pressure, injection/production rates, and cycle frequency, it proposes a refined design principles system encompassing multiple dimensions including geomechanics, cavern sealing, wellbore integrity, mechanical stability, transportation assurance, and operational feasibility for the first time. Constraints are further strengthened to address hydrogen's unique characteristics of high diffusivity and hydrogen embrittlement (HE) effects. This foundation is then built upon to create an optimisation framework targeting multiple objectives, including safety, efficiency, longevity, and economics. A comparative analysis is conducted between traditional physics-based optimisation methods and agent-based modelling approaches enhanced with artificial intelligence (AI), examining their characteristics and application prospects. Furthermore, this paper summarises current challenges facing SCHS in fundamental mechanism understanding, technical methodologies, and engineering practice. The paper also delineates future research directions, including the deepening of full-lifecycle dynamic optimisation, the advancement of fundamental theories and experimental research, the development of intelligent operation management systems, the construction of cross-scale numerical simulation frameworks, and the exploration of offshore SCHS potential. These directions are intended to propel the advancement of SCHS technology towards greater safety, efficiency, and economic viability.