A Review of Underground Hydrogen Storage: Insights into Geological Formations, Key Influencing Factors, Challenges and Case Studies

Underground hydrogen storage (UHS) offers a promising pathway to integrate large-scale renewable energy and decarbonize hard-to-abate sectors by providing seasonal and grid-balancing capacity. This review synthesizes current knowledge on UHS, focusing on three principal geological formations-salt caverns, depleted oil and gas reservoirs, and saline aquifers-and evaluates their respective advantages, limitations, and suitability for hydrogen service. We first examine key physicochemical and geomechanical factors governing storage performance, including rock permeability, caprock integrity, cyclic pressure response, and two-phase flow behavior in hydrogen-brine systems. Next, we address critical challenges such as microbial and mineralogical reactions affecting hydrogen purity, operational constraints imposed by cushion gases, and the need for specialized monitoring and modeling tools tailored to hydrogen's low viscosity and high diffusivity. Through detailed analysis of representative case studies-including Hy Stock (Netherlands), the Jules Verne salt cavern project, and pilot trials in depleted reservoirs-we identify best practices in site selection, cavern leaching, well completion, and real-time surveillance. Finally, we highlight current gaps in regulatory frameworks, economic assessments, and standardization of data reporting, and propose research directions aimed at advancing reservoir-scale experimentation, reactive-transport modeling, and integrated techno-economic analyses. By providing a comprehensive overview of geological, technical, and institutional aspects of UHS, this review aims to inform stakeholders and guide the development of safe, efficient, and cost-effective hydrogen storage solutions that can underpin a resilient, low-carbon energy future.

کلیدواژه ها:

Underground Hydrogen Storage ، Salt Caverns ، Depleted Oil and Gas Reservoirs ، Saline Aquifers ، Hard Rock Caverns