Optimum geological storage depths for structural H2 geo-storage

Abstract H2 geo-storage has been suggested as a key technology with which large quantities of H2 can be stored and withdrawn again rapidly. One option which is currently explored is H2 storage in sedimentary geologic formations which are geographically widespread and potentially provide large storage space. The mechanism which keeps the buoyant H2 in the subsurface is structural trapping where a caprock prevents the H2 from rising by capillary forces. It is therefore important to assess how much H2 can be stored via structural trapping under given geo-thermal conditions. This structural trapping capacity is thus assessed here, and it is demonstrated that an optimum storage depth for H2 exists at a depth of 1100 m, at which a maximum of H2 can be stored. This work therefore aids in the industrial-scale implementation of a hydrogen economy.