Coupled hydro-mechanical analysis of seasonal underground hydrogen storage in a saline aquifer

Hydrogen is promising an efficient and viable solution for low-carbon fuel for different purposes, such as transportation, manufacturing, and electricity. Fluctuating renewable energy production, however, can lead to a temporary imbalance between demand and supply. Nonetheless, it is feasible to mitigate this mismatch by converting the surplus wind power to hydrogen and storing it in geological (subsurface) systems. This work investigates the applicability of underground hydrogen storage in a saline aquifer at the Powder River Basin of Wyoming State. Thus, a 3D coupled hydro-mechanical simulation is presented to evaluate the hydraulic and geomechanical effects during three annual injection-reproduction cycles. A fully calibrated one-dimensional mechanical model has been constructed to characterize the 3D geomechanical model. The simulated results show that the designed storage scenario can be operated with reasonable recovery efficiency such that 78% of injected hydrogen can be extracted to meet 16.7% of household summer electricity consumption for the considered scenario in this study. The surface uplift is highly correlated with the cumulative amount of hydrogen injection and production, and a maximum magnitude of 1.6 cm has been estimated. Integrity analysis of subsurface rock and caprock based on the Mohr-Coulomb criterion demonstrates the safety of underground hydrogen storage at the selected site.