Hydrogen storage production in deep saline aquifers: Numerical modeling and techno-economic–environmental analysis

Underground hydrogen storage in deep saline aquifers has emerged as a promising strategy, offering vast storage capacity while minimizing environmental footprints. This study establishes a theoretical framework to quantify key physicochemical mechanisms, including mineralization, dissolution, and hysteresis, that govern hydrogen dynamics in subsurface environments. Building on these findings, we construct an engineering model for sandstone saline aquifers that incorporates both dissolution and hysteresis. Injection–production simulations indicate that mineralization exerts a negligible influence on hydrogen recovery. In contrast, capillary hysteresis and hydrogen dissolution substantially reduce recovery efficiency. Sensitivity analysis identifies an injection-to-production ratio of 1:1 as optimal. Coupled techno-economic and environmental assessments demonstrate the feasibility of large-scale hydrogen storage in sandstone aquifers. Profitability improves with storage scale, while associated carbon emissions are two orders of magnitude lower than those of conventional fossil-energy systems for comparable energy outputs.