Impurities Associated with Underground Hydrogen Storage (UHS) - Material Integrity Concerns and Mitigation Processes (C2026-00096)

Saba Nava, Hans Sonke, Shane Finneran

Hydrogen industry has been progressing towards safer hydrogen transport in recent years, where hydrogen embrittlement and parameters impacting the process have been scrutinized. Geological reservoirs, including depleted oil and gas fields have been considered for large-scale underground hydrogen storage (UHS) , however, microbial activities in UHS are more significant compared to that of CH4 considering that molecular hydrogen is one of the main electron donors for microbial respiration in the subsurface. This demands an understanding of the subsurface microbial biosphere as well as those contaminants absorbed from the reservoir and introduced during drilling, pumping and mining. This contamination can have adverse impacts on the material integrity of both the downhole equipment as well as the above ground transport network for transporting back produced hydrogen. Since selection of resistant materials is not likely the most economic mitigation methods including appropriate purification processes, are likely required as a key step for hydrogen repurposing projects.
This paper discusses different impurities and how they contribute to a corrosive environment endangering material integrity of the network through a potential synergistic effect with hydrogen embrittlement. Additionally, the potential purification process that can be employed to minimize such impacts will be discussed.