A comprehensive review of site selection, experiment and numerical simulation for underground hydrogen storage

Underground hydrogen storage (UHS) is a promising approach to overcome some of the challenges associated with hydrogen storage and distribution. However, large-scale hydrogen storage faces many challenges due to its specific physical properties, such as low density and high reactivity. Recently, this topic has attracted a lot of interests in both academia and industry. This paper comprehensively presents the current status of UHS research in the areas of site selection, reactions between substances, fluid seepage law, numerical simulations, and operational stability, and also discuss their limitations and provide recommendations for future research and technology development. First, we review the advantages and disadvantages of the four main types of hydrogen storage reservoirs, from which we propose the screening criteria to select a reliable UHS site. Then, we summarize published experimental work related to the interactions H2-fluid-rock under subsurface condition and point out the discrepancies in results from different authors. We also analyze the reasons for different experiment results and provide recommendation to improve the experiment methods and enhance their accuracy. After that, we reviewed the development and applications of numerical simulation methods in UHS research and also discussed the safety and efficiency of UHS, from which the key factors affecting storage efficiency can identified. Finally, we provide our recommendation for a few potential key research directions in UHS.