Hadi Hajibeygi 

Delft University of Technology

Underground hydrogen storage: towards building confidence 

Underground hydrogen storage (UHS) is a relatively new topic compared to the natural gas storage (UGS), and is attracting a lot of research activities due to the hydrogen unique characteristics. Quantification of UHS and UGS (and CCS) similarities and dissimilarities significantly helps to understand the key challenges in enabling UHS both technically and societally. Site selection, field operation and decommissioning strategies are all dependent on reliable simulation of scenarios that represent as much as possible the field scale realities. However, field-scale performance analyses depend on our rigorous understanding of the processes and mechanisms at various scales that drive hydrogen cyclic transport and its interactions in the subsurface, and the subsurface response to the fluctuating pore pressure and hysteric hydrogen transport. The innovative ongoing pilot test sites are also crucial to provide valuable multi-resolution data to reduce modeling uncertainties. But what if a mismatch exists? In what way the multiscale data is expected to help with reducing the uncertainties? We present a multiscale simulation framework to resolve this challenge, and demonstrate its applicability in understanding the storage process whether at lab or field scale. The framework consists of thermo-hydro-mechanical-chemical modeling at various spatial-temporal scales, and allows for connection with multi-resolution data. This scientific framework is applicable to other gas storage and certainly geothermal heat extraction modeling too.