| Popis: |
Climate change, triggered by a continuously rising use of carbon based energy sources, is a global concern. Geological hydrogen storage, e.g. in depleted gas fields or saline aquifers, can overcome imbalances between supply and demand in the renewable energy sector and facilitate the transition to a low carbon emissions society, in this way mitigating climate change. However, a range of subsurface microorganisms utilise hydrogen which may have important implications for hydrogen recovery, clogging and corrosion. We created a novel, globally applicable risk categorization tool based on the published environmental growth constraints of all major hydrogen utilizing microbes (hydrogenotrophic methanogens, hydrogenotrophic sulphate reducing bacteria, homoacetogens and hydrogenotrophic dissimilative iron reducing bacteria) and on reports of paleosterile subsurface environments. Application of the tool to 75 depleted or close to depleted gas fields on the UK continental shelf showed that 9 fields fall either within the ´No Risk´ category with temperatures >122 °C, making them the ideal candidates for hydrogen storage from a microbial risk point of view. Hydrogen storage in the 35 ´Low Risk´ fields with temperatures >90 °C or the 22 ´Medium Risk´ fields with temperatures >55 °C and salinities >1.7 M NaCl will require the careful characterization of the microbial community composition to assure that hydrogenotrophic microorganisms are not present. We recommend against utilising depleted gas fields with temperatures |
