Underground hydrogen storage capacity in saline aquifer

Abstract

Underground hydrogen storage in saline aquifers is an irreplaceable option for large-scale hydrogen usage amid the transition to net-zero, with the urgent demand for clean energy. However, accurate hydrogen storage capacity evaluation is currently hindered by the lack of accessible analytical tools that simultaneously account for engineering constraints and hydrogen-specific biogeochemical losses. To address these gaps, this study hypothesizes that explicitly coupling engineering constraints with quantitative sink terms for microbial consumption and dissolution and diffusive loss will define a net effective capacity that provides a rigorous, safety-constrained baseline distinct from static volumetric estimates. We developed a novel first-order basin-scale screening tool that integrates transport dynamics, equations of state. This framework serves as a theoretical upper-bound estimator designed to evaluate the maximum hydrogen storage capacity subject to engineering constraints and quantitative losses, distinct from predictive reservoir simulations. Applying of the model to a representative basin-scale aquifer, a set of 10 wells with inter-well distance of 5.2 km was determined to reach 1.5 Gt storage volume. Moreover, a total of eleven factors, regarding the reservoir parameters, fluid properties, engineering strategies, and their effects on the hydrogen storage capacity, were specifically analyzed. Results show that long operational time (i.e., 1000 years) usually results in increased storage volume to reach the maximum storage capacity. We conclude that while saline aquifers offer huge storage potential, their technical feasibility is strictly governed by the coupling of hydraulic injectivity and operational time. Overall, this study provides a powerful tool for accurately and efficiently quantifying hydrogen storage capacity and optimizing strategies in saline aquifer.