Application of CO₂ Geologic Storage Experience to Underground Hydrogen Storage Reservoirs

Grid-scale energy storage options offer a promising path for decarbonizing power generation, enabling utilities to balance intermittent generation from wind and solar by storing excess electricity for days, weeks, or even months. Analytical assessments have been conducted on the potential of natural underground containments such as salt caverns, deep saline aquifers, depleted hydrocarbon reservoirs, and coal mines, to store electricity in the form of electrolytically produced hydrogen. These researches cover a quantitative and qualitative analysis of the geological, reservoir, and technical criteria that must be met by the subsurface hydrogen storage facility. In this paper, we utilize a 3D numerical model to analyse the suitability of subsurface structures for large-scale storage of hydrogen. Numerical models are widely used in reservoir operations to enhance predictions. The modelling techniques applied here give better visualisations of the storage capacity, and fluid dynamics during hydrogen injection and withdrawal from the reservoir. The modelled parameters include those variables required for describing fluid flow in porous media namely pressure, temperature, depth, thickness, density, viscosity, porosity, relative permeability, and in-situ reservoir fluid composition. The simulations are carried out using ECLIPSE 300 (Schlumberger), a multi-phase, multi-component reservoir simulator to evaluate: (a) distribution of injected hydrogen gas in the underground, and (b) the storage capacity of the Viking A field. According to our modelling estimates, the reservoir has a total storage capacity in the range of 0.6 MT and a productivity of approximately 0.26 MT of hydrogen, over 5.6 years. The results presented are computer modelled only, thus detailed flow experiments focused on the reaction of hydrogen with the rock and reservoir fluids is recommended for further studies.