Integrating hydrogen production and subsurface storage: toward a sustainable hydrogen economy: a critical review

For energy transition and energy innovation, hydrogen has emerged as a pivotal clean energy carrier bridging renewable generation and industry-scale decarbonization. As renewable penetration increases with known spatio-temporal fluctuations, the ability to store energy over days to seasons becomes a critical limitation to energy system resilience. Integrating multi-sourced energy into existing infrastructure therefore demands efficient, safe, and cost-effective energy storage solutions across the supply chain. Among available options, underground geological storage represents a viable large-scale, long-duration technology capable of balancing seasonal energy fluctuations. Hydrogen’s low molecular weight, high diffusivity, and reactivity present both opportunities and challenges for secure storage, while surface-based methods such as compression, liquefaction, and adsorption remain constrained by cost, capacity, and scalability. Subsurface formations, including salt caverns, depleted hydrocarbon reservoirs, coal seams, aquifers, and abandoned mines, offer vast potential storage capacity but require detailed understandings of coupled geomechanical, geochemical, and microbiological processes that govern hydrogen injection, storage and recovery. Gas–rock–brine interactions, caprock integrity, cushion gas dynamics, and microbial methanogenesis significantly affect hydrogen retention and operational efficiency. This review synthesizes the state of knowledge on hydrogen storage through geological media, integrating scientific, engineering, and environmental perspectives while coupling storage technologies with emerging hydrogen production pathways—blue, green, and orange hydrogen—derived respectively from fossil reforming with carbon capture, renewable-driven electrolysis, and geological stimulation such as serpentinization. Case studies from the United States, Europe, and Asia confirm the technical feasibility of underground storage yet highlight persistent challenges in long-term monitoring, leakage prevention, and economic optimization. Looking forward, the incorporation of artificial intelligence (AI), distributed acoustic fiber-optic sensing, and reactive transport modeling will enhance real-time assessment and system design. Collectively, these developments affirm that large-scale geological hydrogen storage is not merely a technical option but a strategic necessity for achieving a secure and decarbonized global hydrogen economy.