Microbial considerations/aspects of underground hydrogen storage

The utilization of hydrogen (H2) gas as a renewable energy source has witnessed a significant advancement. A fundamental challenge for ensuring continuous supply lies in its secure and economically viable underground hydrogen storage (UHS) within the matured or depleted oil and gas reservoirs, salt caverns, and deep aquifers. These environments harbor a substantial amount of microbial activity. Microorganisms within subsurface environments can incorporate H2 into their metabolism, potentially resulting in a range of undesirable outcomes like H2 loss, hydrogen sulfide (H2S) generation, methane (CH4) production, acid establishment, pore blockages, and subsurface facility corrosion. This chapter summarizes an overview of the present knowledge and methodologies concerning microbial-associated risks in the context of UHS. Encompassing the fundamental investigations into subsurface microbiology, findings from field experiments, and accumulated experience.