Hydrogen Adsorption on Sub-Bituminous Coal: Implications for Hydrogen Geo-Storage

Hydrogen is a clean fuel that can potentially revolutionize the energy supply chain and decarbonize fuel consumption. However, a key hurdle that needs to be overcome before a full-scale hydrogen economy can be established is hydrogen storage which is currently the main limitation. Here, we propose that hydrogen gas can be stored in underground coal seams, where it adsorbs on the coal surface. However, currently, no hard data related to such a procedure exists. We, therefore, demonstrate experimentally that significant amounts of hydrogen gas can be stored via this route. Hydrogen adsorption capacities reached 0.6 moles H₂/kg of coal at 14.3 MPa, and adsorption capacity initially increased strongly with pressure (up to ∼4 MPa) and then plateaued out, while temperature only had a very minor influence. This study provides fundamental data for hydrogen storage in coal seams, and thus aids in the industrial implementation of a hydrogen supply chain.