Proposals should address most of the following elements:

• Development of techniques, tools, and methods to better characterise and understand processes controlling the formation, migration, and accumulation of hydrogen in the subsurface as well as natural emissions to the surface, and to establish a set of criteria to confidently identify prospective areas. Proposals should include at least one case study area (two if the budget allows it) to test remote sensing and hydrogen sensors, gather geophysical data from active or passive seismic, gather geochemical data, possibly logging tool (tools which are run into the well after drilling and which, with specific development would help to characterize hydrogen in the well) in order to calibrate methods with minimal environmental impact;
• Guidelines for systematically identifying potential natural hydrogen sources in Europe by determining the combination of key parameters and conditions necessary to its generation;
• Analogue experiments to simulate in situ conditions (temperatures, pressures, rock mineralogy and chemistry, geofluid compositions) controlling the generation of natural hydrogen and its kinetic (in mol/kg/s);
• Numerical models to predict the dynamics of large hydrogen systems, from the source (generation, migration, and alteration), trapping in reservoirs if appropriate, to emission/leakage at the surface. It should allow the determination of a “Hydrogen Window” i.e. both chemical and physical subsurface conditions to generate natural hydrogen, applicable on specific or general conditions. Ultimately, the numerical models should allow quantifying the possible volume (in tonnes) and production rate (in tonnes/year) of selected sites of natural hydrogen in Europe in the coming years and characterizing its potential renewable aspect;
• Characterisation of purification requirements of selected expected gas compositions, identification of possible technologies, and test of their performances at laboratory scale.
• Life Cycle Assessment to determine the environmental performance of exploring, extracting, and producing natural hydrogen at this early stage of knowledge and at relevant specifications (i.e. including purification and other post-production treatments) notably in terms of (i) Greenhouse gas emissions range (in kg CO2 eq. per kg H2 produced) including possible associated gases and fugitive leakages, (ii) critical raw materials use, (iii) water resources consumption, and (iv) land use;
• A check (based on the LCA results) whether natural hydrogen can be classified as Renewable Fuels of Non-Biological Origin (RFNBO) established under the Renewable Energy Directive (RED II). This would allow framing natural hydrogen into EU certifications which will ensure a commercialisation of the natural hydrogen to clients willing to decarbonise their activities. Elements to establish the right taxonomy of natural hydrogen to be certified under EU certification schemes should be provided;
• A conceptual study to assess the levelized cost range of hydrogen production (in € per kg H2 produced) taking into account, key parameters such as drilling design, operational costs, periodic work-over, abandonment costs, purification requirement, expected volume and well deliverability. A parametric model integrating the outputs of the conceptual study will allow the economic assessment of prospects on a case-by-case basis.
• At the same time, a bottleneck is to access these reserves in a safe and cost-efficient manner. Thus, research on identifying challenges related to well construction, drilling dynamics, and how to address them, will provide tools and methods to advance exploration and production of natural hydrogen, and mitigate leakages from prospection to exploitation;

In addition, proposals may address the following:

• Identification, description, and evaluation of the specific geological formations, processes, and settings that can potentially produce natural hydrogen in economically viable quantities in Europe;
• The social acceptability of these projects is also key to operate. Protocols are needed to improve public perception and acceptance including communication strategies dedicated to specific stakeholders with emphasis on the local benefits provided by the resources, and on the activities and their related safety risk mitigation;
• Mitigate the risks related to the safety of handling hydrogen in such quantities and opposition by the public, to accelerate the transition towards low-carbon energy solutions.

As relevant, proposals are encouraged to involve European and national geological research institutes.