When the U.S. Geological Survey released its first Geologic Hydrogen Prospectivity Map in January 2025, it marked a turning point for an alternative resource that had long been proven but remained at the margins of the geoscience industry. The map identified regions across the contiguous United States where natural geologic conditions might favor the formation and trapping of hydrogen gas, with large areas showing potential.
While the map did not confirm the existence of recoverable accumulations, it provided a widely accessible starting point to guide exploration and prioritize areas for further study. In the months since, energy companies, research institutions and national geological surveys have launched new initiatives to test the concept in the field. Early wells have reported hydrogen concentrations that suggest viable reservoirs might exist under the right geological conditions. The growing interest is reminiscent of the early days of the shale and hydraulic fracturing revolution, when new thinking and technology transformed previously uneconomic resources into a new energy frontier.
From Novelty to Potential Resource
Geologic hydrogen, sometimes called “white” or “gold hydrogen,” forms through several natural processes. These include serpentinization of ultramafic rocks, oxidation of iron-bearing minerals and radiolysis of water by natural radiation. These reactions occur over long timescales and might continue today, raising the possibility that some hydrogen systems could be self-renewing.
The idea that the Earth might generate a clean, replenishing energy source has attracted attention worldwide. Natural hydrogen seeps have been documented in regions such as Mali, Russia, France and Australia. In Mali, the Bourakébougou discovery in 1987 demonstrated that hydrogen venting from the subsurface could provide a reliable local energy source for years. These examples have moved the discussion from theoretical to practical.
Lessons from Previous Energy Transitions
The history of energy development shows that new resources rarely emerge overnight. The shale gas boom of the early 2000s was the product of decades of research and persistence and it is likely that geologic hydrogen will follow a similar path.
Exploration methods from petroleum geology, such as seismic imaging, geochemical sampling and reservoir modeling are being adapted to identify hydrogen systems. Yet hydrogen behaves differently than hydrocarbons. It is small, mobile and reactive. It can diffuse through seals and react with surrounding minerals, which means traditional hydrocarbon traps might not apply. Understanding new types of traps, seals and migration pathways will be critical for successful exploration.
Understanding the Subsurface Hydrogen System
Geologic hydrogen presents both scientific and technical challenges. Understanding the processes that generate, accumulate and retain hydrogen requires an integrated approach that combines geochemistry, petrology, structural geology and geophysics.
The concept of continuous generation also introduces new questions. If hydrogen is produced steadily over time, how does that affect reservoir behavior, recharge potential and sustainability? Are these systems more like hydrocarbon reservoirs or do they behave dynamically, as open systems? Research efforts are beginning to focus on how hydrogen interacts with minerals, how it migrates through crystalline rocks and how microbial activity might influence its fate in the subsurface.
Technical and Economic Challenges
If economically recoverable accumulations can be proven, geologic hydrogen could complement existing hydrogen production methods and help strengthen a lower-carbon energy mix. Currently, most hydrogen is produced from natural gas through steam methane reforming, a process that emits carbon dioxide and is referred to as “gray hydrogen.” In contrast, “green hydrogen” is produced through electrolysis powered by renewable energy, but this approach remains costly and limited by the availability of clean electricity.
Geologic hydrogen could offer a third option: hydrogen generated naturally and trapped underground with minimal carbon emissions from production. However, challenges remain. Hydrogen can embrittle metals and diffuse through seals and it requires specialized materials and infrastructure for transport and storage. Regulatory frameworks and industry standards will need to evolve as exploration advances.
A New Opportunity for Exploration Geoscientists
For geoscientists, the emerging hydrogen field represents a rare combination of familiar tools and new scientific questions. The skills used to discover and develop oil and gas resources such as field mapping, subsurface interpretation and reservoir analysis are directly applicable to this new target. At the same time, hydrogen introduces unique geochemical and physical properties that will challenge conventional exploration models.
Universities and professional organizations are beginning to recognize the potential. New research programs and workshops are emerging to train students and professionals in hydrogen geoscience. The U.S. Geological Survey’s mapping effort has already spurred collaboration between academia, government and industry. These partnerships will be essential for developing the data, technology and workforce needed to move from concept to commercial reality.
For many geologists, geologic hydrogen offers a renewed sense of purpose. It recalls the early spirit of exploration when curiosity, innovation and risk-taking led to major breakthroughs in understanding the Earth and its resources.
Looking Ahead
Natural hydrogen systems may be waiting to be discovered, mapped, and developed. The 2025 USGS Geologic Hydrogen Prospectivity Map is only the first step in identifying where those systems might exist. Each exploration well and field survey adds to the growing body of knowledge about this promising resource.
While the scientific and technical questions remain complex, the potential rewards could be significant. For exploration geoscientists, geologic hydrogen offers a chance to lead once again in defining a new frontier and connecting geologic understanding with the energy transition ahead.