Hydrogen (H2) is considered to play an essential role in reducing greenhouse gas emissions, supporting decarbonization, and ultimately, in achieving a future low-carbon energy system. As the demand for hydrogen is expected to vastly increase (double by 2030) and current production methods involve either high costs or significant CO2 emissions, natural hydrogen, also referred to as white or gold hydrogen, has moved into the focus of geosciences. Natural hydrogen is primarily formed by water-rock reactions of which serpentinization (hydration of ultramafic rocks), oxidation of ferrous iron (e.g., hydrothermal alteration of biotite in crystalline granitic rocks), water radiolysis, and hydration of Si-radicals in fault zones, but also over maturation of organic matter are considered as most relevant. Additionally, biotic processes such as nitrogen fixation or fermentation of organic matter are described to produce considerable amounts of H2 (several 100s of ppmv), in particular in the shallow most subsurface, wet soils, and aquifers. The project aims at providing a first evaluation of the natural hydrogen potential of selected sites in the Kingdom of Saudi Arabia by applying an integrated approach combining field work and laboratory analyses that will ultimately, allow for a comprehensive first-order characterization of potential hydrogen systems. Field work consisting of soil gas measurements, gas flux measurements, and detailed characterizations of outcrops (e.g., potential source rocks such as ultramafic complexes) will be complemented by laboratory gas chromatography analyses (molecular composition of soil gas and stable carbon/hydrogen isotopy), water analyses (pH, dissolved anions/cations, dissolved gases), and fluid inclusion studies (Raman spectroscopy and microthermometry). By combining different disciplines (i.e., geochemistry, hydrogeology, mineralogy, and structural geology) different hydrogen system elements, in particular source and migration, will be targeted by the project.

The project aims at providing a first-order characterization of potential natural hydrogen systems in the Kingdom of Saudi Arabia and ultimately, at evaluating the natural hydrogen potential at selected sites. This shall be achieved by applying a manifold of methods (i.e., soil gas analyses, stable isotope measurements, water analyses, fluid inclusion studies, analyses of surface geology etc.) from different geoscientific disciplines (geochemistry, hydrogeology, mineralogy, and structural geology). A special focus will be led on the identification of surface seepage and the characterization of source rocks, in particular ultramafic rocks in ophiolite complexes. Although, a detailed evaluation of Saudi Arabia’s natural hydrogen potential clearly goes beyond the scope of this project, it will deliver valuable information for future natural hydrogen exploration efforts. In addition, the project’s results will be of great use for developing appropriate natural hydrogen exploration workflows. The main deliverable of the project will be a detailed report summarizing its results. Additionally, the results will be published in peer-reviewed journals (e.g., International Journal of Hydrogen Energy) and presented at scientific conferences (e.g., H-Nat, AAPG, PACROFI/ECROFI) to maximize their impact on the scientific community, policy makers, and stakeholders.