Towards Long-Term Operational and Geo-Mechanical Stability of Underground Hydrogen Storage in Salt Caverns

Summary Hydrogen is rapidly gaining momentum as a cornerstone of the global transition to cleaner energy systems, providing a versatile and low-carbon fuel alternative across a range of industries, including power generation and transportation. However, large-scale hydrogen storage poses significant challenges, as effective storage solutions are critical for balancing supply and demand, especially for renewable energy sources. Underground salt caverns present a promising option for hydrogen storage due to their unique mechanical properties, such as high impermeability and self-sealing behaviour under stress. These characteristics make salt caverns particularly suited for long-term, safe, and high-pressure hydrogen storage. To ensure the reliable performance of hydrogen storage systems, it is essential to thoroughly understand the behaviour of salt caverns under operational conditions. This study adopts a comprehensive geo-mechanical modelling approach to assess the performance of salt caverns repurposed for hydrogen storage. By employing finite difference modelling, we simulate the stress, deformation, and displacement responses of the cavern structure. The geological model is developed based on real-world data from the Zechstein Group in East Yorkshire, United Kingdom, a region with favourable geological conditions for underground storage. The study incorporates detailed sensitivity analyses to evaluate the influence of varying operational parameters, such as injection pressures and cycle frequencies, on the stability of the caverns. These analyses provide a clear understanding of how operational stresses affect the long-term behaviour of the storage system, including potential risks related to creep, subsidence, and deformation. The results offer crucial insights into the optimization of design and operational parameters for hydrogen storage caverns. This work contributes to the development of safe, efficient, and scalable hydrogen storage infrastructure, which is a critical enabler for the widespread adoption of hydrogen as a clean energy vector.