Thermo-physical numerical model for hydrogen storage in underground tanks and caverns

Compressed hydrogen storage is an energy-efficient alternative to liquefaction, and in the absence of underground salt formations, reservoirs like rock caverns, mining shafts, and cased boreholes are gaining traction. The limited reservoir volume constrained by excavation or drilling results in short, high-pressure cycles. Thus, effective temperature control is crucial to maintain integrity and maximize hydrogen density. This study presents a validated numerical model with open-access code for simulating heat exchange and predicting operating pressure and temperature for underground hydrogen storage in tanks or caverns. The validation encompasses analytical solutions and existing cylindrical models. Results highlight the heat transfer's impact on hydrogen density and the limited penetration depth of the thermal perturbation, underscoring the need for simulating heat transfer across multiple layers, especially in restrictive media like cement. Managing injection and extraction flow rates is crucial to limit temperature peaks for larger radius reservoirs where heat transfer is less efficient.