Numerical investigation of fluid dynamics in aquifers for seasonal large-scale hydrogen storage using compositional simulations

The development of renewable energy is crucial for reducing CO2 emissions. Hydrogen is an important clean energy source that can go some way to solving seasonal energy shortages. Aquifers, widely distributed, present viable options for seasonal hydrogen storage, although current understanding remains limited. This study utilizes numerical simulations to investigate the impacts of porosity, permeability, hysteresis, dissolution, diffusion, and storage cycles on hydrogen recovery efficiency. The results reveal that: (1) Recovery efficiency increases by 7.83 % with higher injection pressure due to reduced porosity, though upper pressure thresholds limit the selection of low-porosity reservoirs. (2) A decrease in vertical permeability enhances recovery efficiency by 1.81 % by mitigating pressure decay rates. (3) Hydrogen's interaction with the aquifer significantly impacts recovery efficiency, with the hysteresis effect accounting for 13.62 %. In comparison, dissolution and diffusion contribute less than 1 %. The combined effects of hydrogen further degrade recovery efficiency. (4) Implementing multiple storage cycles can improve recovery efficiency by 29.13 %, but careful management of operating pressure during these cycles is essential. These findings provide valuable insights into the mechanisms of hydrogen storage in aquifers and inform strategies for enhancing recovery efficiency.