Abstract This study assesses the technical and commercial feasibility of repurposing a depleted gas reservoir for large-scale underground hydrogen storage (UHS) using surplus renewable electricity. Through the case study of the Hy1 field in the UK it is shown how legacy hydrocarbon infrastructure can be tailored to support net zero goals and updates similar strategies for hydrogen storage in regions such as the UAE. The UK aims to cut net energy consumption by 30% by 2030 and achieve net zero by 2050. Surplus Scottish wind power is earmarked for green hydrogen production via electrolysis, with more than 1 GW of capacity planned. A detailed screening study identified the Hy1 onshore depleted gas field as a strong UHS candidate, featuring 18% porosity, 150 mD permeability, 50 m gross thickness, and 250 bar initial pressure. A 3D model was developed using CMG GEM1 simulation which performs compositional simulation, combining seismic data and 15 years of production history. Multiple well placements and scenarios (H₂, CO₂, N₂) were tested for scientific and economic performance. Simulation results confirmed that the Hy1 field behaves as a volumetric tank, with an estimated gas-in-place volume of 8 Bscf, validating its suitability for UHS. Crestal wells located within the anticline structure displayed superior injection and withdrawal efficiency compared to other configurations. Hydrogen was identified as the most cost-effective cushion gas due to its availability on-site from electrolysis and favorable performance characteristics. The field demonstrated the capacity to store up to 15,000 tonnes of hydrogen, with achievable injection and withdrawal rates of 300 and 200 tonnes per day, respectively. Major risks include trap integrity, caprock sealing effectiveness, microbial activity that may alter stored hydrogen, and the co-production of residual methane. These risks require management through optimized cushion gas selection and the installation of surface separation systems to ensure hydrogen purity. Clustering multiple UHS sites was also shown to be essential for scaling up to gigawatt-level electrolyzer deployments, ensuring a dispatchable and economically viable hydrogen supply chain This study is among the first to simulate cyclic hydrogen injection in a mature UK gas field while integrating economic assessments of different cushion gas options. It presents a practical and transferable workflow for other regions, particularly the UAE, where depleted fields such as Habshan and Bab could be repurposed using solar-powered electrolysis and extensive legacy subsurface data. This framework enables faster screening, securing, and development of UHS projects supporting both domestic decarbonization and hydrogen export strategies. Furthermore, this study introduces a new operational consideration management of co-produced methane during withdrawal which is expected to become a significant economic and regulatory factor in future UHS developments.
Gupta et al. (Mon,) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: