The influence of the first filling period length and reservoir level depth on the operation of underground hydrogen storage in a deep aquifer

Underground storage is a method of storing large amounts of renewable energy that can be converted into hydrogen. One of the fundamental problems associated with this process concerns determining the timing and amount of injected gas in the first filling period for the operation of an underground storage facility. Ascertaining the hydrogen flow rate is essential to ensure that the capillary and fracturing pressures are not exceeded. The value of the flow rate was assessed by modelling the injection of hydrogen into a deep aquifer. The best initial H2 injection period was found to be five months. The volume of the cushion gas and the total storage capacity expanded with the extension of the first filling period length. The working capacity grew as the depth increased, reaching maximum values at depths of approximately 1200-1400 m. This depth was considered optimal for storing hydrogen in the analysed structure.(c) 2022 The Authors. Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC. This is an open access article under the CC BY license (http://creativecommons.org/ licenses/by/4.0/).

Automated summary

Underground storage is a viable method for storing renewable energy as hydrogen. Determining the timing and amount of injected gas is crucial for the operation of such facilities. Modeling the injection of hydrogen into a deep aquifer helped assess the optimal flow rate and the benefits of extending the first filling period. Storage capacity increased with longer filling periods, and the recommended depth for hydrogen storage was found to be around 1200-1400 m.