Hydrogen in Geological Formations: From Natural Accumulations to Underground Storage—Progress, Challenges and Prospects

Dear Colleagues,

Hydrogen is increasingly recognized as a strategic energy vector, and geological formations are becoming central to its future, both as potential sources of natural (geologic) hydrogen (including white and orange hydrogen) and as large-capacity sites for underground hydrogen storage (UHS). While these applications differ in purpose, they share a common subsurface scientific and technological foundation, with closely related challenges in geology, geochemistry, reservoir structure, containment and monitoring.

This Special Issue aims to present and disseminate recent advances and perspectives on hydrogen in the subsurface, spanning the continuum from natural hydrogen generation (both white and orange hydrogen), migration, trapping and resource appraisal to UHS site selection, design, operation and performance in salt caverns, depleted oil and gas fields and saline aquifers. We welcome original research articles and reviews that improve predictive understanding and operational confidence, supported by laboratory studies, field observations, pilot demonstrations and robust modeling and verification.

In addition, the Special Issue explicitly addresses progress, challenges and prospects for deployment, including technology and market maturity for both natural hydrogen and UHS, viable commercialization pathways and off-take structures and synergies with ongoing initiatives and infrastructure (e.g., CO₂ storage/CCUS, natural gas storage, geothermal, hydrogen valleys and regional hydrogen backbone plans). Contributions that identify gaps, barriers, enabling policies/standards, risk-sharing mechanisms and practical roadmaps for market uptake are particularly encouraged.

Topics of interest for publication include, but are not limited to

• Subsurface science and engineering
• Natural (geologic) hydrogen (white/orange): generation mechanisms and processes, fluxes, migration and trapping
• Exploration and appraisal workflows: play concepts, prospectivity mapping and uncertainty
• Reservoir characterization and heterogeneity; caprock sealing; fault/fracture controls
• Well integrity, materials compatibility and operational integrity management
• Multiphase flow and reactive transport; geochemical and microbial processes
• Storage performance in salt caverns, depleted reservoirs and saline aquifers (cycling/deliverability)
• Leakage pathways, risk assessment and safety and environmental considerations
• Monitoring, measurement and verification (MMV): geophysics, geochemistry, tracers and pressure/temperature
• Lab-to-field upscaling, model validation, pilots/demonstrations and data-driven workflows
• Deployment, markets and commercialization
• Technology readiness and maturity assessment for natural hydrogen and UHS
• Cost, performance and risk drivers; benchmarking and sensitivity/uncertainty analysis
• Business models, value chains and commercialization pathways
• Regulatory frameworks, standards, permitting, liability and certification (including hydrogen quality)
• Mapping synergies with existing initiatives/infrastructure (CCUS, gas storage, geothermal, hydrogen valleys/backbones)
• Algorithmic tools development to simulate, monitor and predict future storage using potential site scenarios
• Identification of gaps and barriers and actionable roadmaps to accelerate market uptake

Dr. Emmanuel Stamatakis
Dr. Spyridon Bellas
Guest Editors

Manuscript Submission Information

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• natural (geologic) hydrogen
• white or gold hydrogen
• orange hydrogen
• underground hydrogen storage (UHS)
• subsurface geology and reservoirs
• caprock and well integrity
• geochemistry
• microbial processes
• multiphase flow and reactive transport
• monitoring, measurement and verification (MMV)
• commercialization and market maturity