MICROBIAL DYNAMICS IN HYDROGEN STORAGE SIMULATION CONDITIONS

Hydrogen has been identified as a flexible energy carrier with zero or negative emission across multiple energy systems, and existing natural gas infrastructure could be leveraged if hydrogen gas (H₂) was blended with methane (CH₄). However, the compatibility of adapting the current CH₄ storage strategies to include H₂ injection has not been fully demonstrated. It is essential that we understand the impact of H₂ gas on the naturally occurring microbial community of subsurface storage reservoirs before deploying large-scale H_2-CH₄ storage,

We collected produced fluid and sediment from a H₂ storage target formation in southern Illinois and ran a series of high pressure, high temperature reactors under hydrogen storage conditions with a 15% H₂-85% CH₄ gas blend for up to 21 days. We completed qPCR, 16S rRNA sequencing, geochemical analysis, and SEM for each reactor. We also completed geochemical analysis, qPCR, 16S sequencing and metagenomic sequencing of the initial fluid. Previous hydrogen storage work has linked subsurface microorganisms with methanogenesis, hydrogen sulfide production, acid production, and microbial corrosion. Our results show minimal methanogenesis, but a high potential for hydrogen sulfide production. DNA analysis demonstrated a microbial community was selected for after just 1 day of exposure to H₂-CH₄. We anticipate our hydrogen simulation experiments will aid in describing the overall timeline and cascading effects of individual microbial interactions present in these environments.