El natural hydrogen or white hydrogen In a very short time, it has gone from being a geological curiosity to emerging as one of the most serious candidates to revolutionize the energy transition. While the world has focused on producing hydrogen from natural gas or renewable electricity, beneath our feet there could be trillions of tons of geological hydrogen generating continuously for millions of years.
In several points around the world - from a discreet forest in Bavaria From a village in Mali to the subsoil of Huesca, very solid evidence is emerging that this resource not only exists, but that It can be extracted cost-effectively and with a minimal carbon footprintThis is triggering a veritable "gold rush" for white hydrogen, as governments, universities, and companies try to adapt their legal frameworks, technologies, and business models to a resource that until recently was virtually ignored.
What is natural hydrogen and why does it matter so much?
Natural hydrogen (white or golden) It is hydrogen that is found freely underground, without needing to be manufactured through industrial processes. Unlike hydrogen produced from fossil fuels or electricity, this is generated spontaneously by geological reactions in the Earth's crust and mantleand can accumulate in underground traps similar to those of natural gas.
The big difference compared to other forms of hydrogen is that, in this case, the resource is already available. available in gaseous statewithout going through intensive transformation processes. That implies, on paper, much lower production costs and a very small environmental impact, provided that the extraction is done carefully and under strict regulatory frameworks.
The International Energy Agency estimates that Global demand for hydrogen could triple by 2050Much of that hydrogen will be used in sectors that are very difficult to decarbonize: steelmaking, maritime transport, aviation, heavy chemicals or very high temperature industrial heatwhere direct electrification is complicated or uneconomical.
Until now, the vast majority of hydrogen has been produced from natural gas or coal, with strong associated CO₂ emissionsLess than 1% is "green," obtained through water electrolysis using renewable energy. This is where natural hydrogen comes into play as a possible alternative. technological and economic shortcutIf there is a sufficient quantity available, it could supply a significant part of that demand without needing to deploy so many electrolysis plants or consume so much renewable electricity.
Estimates from the US Geological Survey suggest that the Earth's crust could store about 5,6 billion tons of white hydrogenAlthough most of it would be at depths unreachable with current technology and costs, geologists calculate that even if only a small percentage—around 2%—could be harvested, there would be enough hydrogen to to sustain humanity's needs for about 200 years at the expected rate of consumption.
How white hydrogen forms deep within the Earth
One of the keys to the potential of natural hydrogen is that it is generated by geological processes that are still active todayThe most frequently cited is the so-called serpentineWhen iron-rich rocks from the mantle—such as peridotites—come into contact with water at temperatures between 200 and 350 °C, the iron "steals" the oxygen from the water, and what remains is molecular hydrogen (H₂).
This process occurs especially in areas of Oceanic crust and ancient seabeds that have become trapped in mountain ranges, or in regions where the crust is highly fractured and allows water to seep deep into the Earth. The result is enormous volumes of hydrogen that can rise and concentrate in geological traps, in the same way as with natural gas.
Besides serpentinization, there are other mechanisms that produce white hydrogen: decomposition of iron-rich sedimentary rocks, radiolysis (a kind of “natural electrolysis” caused by radiation from radioactive elements in the subsoil) or the degassing of the Earth's mantle, which releases gases towards the upper crust.
Although for decades it was thought that free hydrogen was extremely rare and that any small accumulation would be quickly consumed by microorganisms of the subsoilRecent models indicate that this view was too pessimistic. New measurements and drilling on different continents show that, far from being a rarity, native hydrogen is much more widespread than previously thought, even at relatively shallow depths.
An important consequence of these processes is that natural hydrogen could behave almost like a renewable resourceIn the Mali field, for example, the gas outlet pressure has remained stable for more than a decade, suggesting that the system regenerates continuouslyAs long as the extraction rate does not exceed the underground generation rate, the deposit would behave as a long-lasting and stable source.
Colors of hydrogen: from black to white
To put white hydrogen in context, it is worth remembering the classic color classificationwhich does not refer to the appearance of the gas (hydrogen is colorless) but to its origin and its associated carbon footprint.
El black or brown hydrogen It is obtained by gasifying coal (bituminous coal, lignite). It is the option with the greatest climate impact, as it releases large quantities of CO₂ and other pollutants. A less polluting, but also very problematic from an environmental point of view, is... gray hydrogen, which is produced by reforming natural gas: methane is combined with high-temperature steam to generate hydrogen and carbon dioxide.
An evolution of this process is the blue hydrogenwhich also starts with natural gas, but includes CO₂ capture, use and storage (CCUS). In this case, the greenhouse gas is not released into the atmosphere, but is confined in geological formations or used in industrial processes, significantly reducing the climate footprint, although with added costs and significant technical challenges.
Other interesting avenues are the Turquoise hydrogenwhich is obtained through methane pyrolysis, generating hydrogen and solid carbon instead of CO₂ (which facilitates its management), and the yellow hydrogen, which comes from the electrolysis of water using electricity from the conventional grid, with a carbon footprint that will depend on the country's electricity mix.
At the low end of the emissions spectrum are the pink hydrogen -nuclear-powered electrolysis- and the much-touted green hydrogen, which is obtained from water and electricity from renewable sources (wind, solar, hydropower). The latter is the European Union's and especially Spain's big bet, but today it remains several times more expensive than gray hydrogen, with differences that are around a factor of eight in some analyses.
This fan was missing one color: the white or golden hydrogen, the one that forms in nature and is extracted directly from the subsoil. Its great advantage is that It does not require a prior industrial conversion processBeyond drilling and conditioning the well and, in many cases, separating the hydrogen from other accompanying gases, this makes it a particularly attractive candidate for achieving Low-carbon hydrogen at very competitive costs.
Real cases: from the “eternal fires” to the Bavarian forest
The idea that the subsoil can emit flammable gases unrelated to oil or natural gas is not new. Places like these have been known since antiquity. “Eternal fires” of Mount Chimera, in Yanartaş (Türkiye)where flames continuously erupt from the rock. Texts by Ctesias of Cnidus and Pliny the Elder already mention these curious emanations more than 2.500 years ago, although their exact nature was unknown at the time.
A huge leap in knowledge came with the discovery of the hydrothermal vents of Lost City, in the North Atlantic, in the early 2000s. These are underwater calcite structures, known as white smokerswhich expel very hot, alkaline brines laden with gases. Some studies measured these springs up to 70% native hydrogenwith emissions of between 5 and 10 million cubic meters per year per stack. It is suspected that there are thousands of similar systems scattered throughout the oceanswhich gives an idea of the global magnitude of the phenomenon.
On land, one of the most striking discoveries were the subcircular depressions of the Voronezh oblast, about 600 km south of Moscow, discovered by Russian geologists Vladimir and Nikolay Larin. These structures, named “fairy circles”These structures are characterized by a total absence of vegetation and the constant release of mixtures of hydrogen, nitrogen, and helium. After years of relative indifference, teams from the French IFPEN validated their observations, and since then, similar structures have been identified in Australia, Brazil, Mali and the United States.
Another milestone came by chance in 1987, when a shallow well for water was drilled in Bourakébougou, MaliDuring the work, an explosion occurred because a worker was smoking, and the well was plugged under the mistaken belief that it contained a small pocket of natural gas. It wasn't until 2011 that the local company Hydroma analyzed the gas and discovered that it contained [unspecified substance]. approximately 98% hydrogenSince then, more than 25 wells have been drilled, all with concentrations between 90 and 99% of native hydrogen.
The Bourakébougou case is today the only commercially exploited natural hydrogen depositThe gas is burned on-site to produce electricity for the local community, and most strikingly, the pressure in the wells has barely changed in 14 years, reinforcing the idea that it is a sustainable system. self-sustaining through continuous geological processes.
In Europe, a very illustrative example is the work of the geologist Jürgen Grötsch in a forest in northern Bavaria. After decades with the Shell oil company, he now walks the land with students from the University of Erlangen-Nuremberg, practicing small drilling one meter deep and placing gas sensors to "sniff" the subsoil. In one of those measurements, slightly more than 500 parts per million of hydrogenThat is, around 0,05% of the gas analyzed, enough to confirm the presence of an interesting vein at depth.
Spain and Europe: Aragon as the spearhead
In the European context, Spain has jumped onto the map of natural hydrogen thanks to Rediscovery of the Monzón-1 well, in the province of HuescaDuring the 60s, the National Petroleum Company of Aragon SA drilled in the area in search of hydrocarbons and came across pure hydrogenAt that time, with no market for this gas and no suitable technology to exploit it, the discovery was shelved.
Today the situation has changed radically. The startup Helios AragónWith links to major energy players, he has recovered that historical data and is proposing an ambitious project to convert Monzón-1 into Europe's first producing natural hydrogen wellThe company estimates that the deposit could produce between 55.000 and 70.000 tons per year for about 25 or 30 years, which would mean around 1,1 million tons of hydrogen throughout its useful life.
The planned investments are considerable: there is talk of approximately 14 million euros initially in 2025 and a total that could reach 900 millones de eurosThe idea is to use techniques very similar to those used in the natural gas wellsbut adapted to the characteristics of hydrogen, and market the gas directly through water pipelines towards nearby industries, without the need for large-scale storage.
The project involves deep drilling in the Monzón area, near the A-22 motorway and the Zaragoza-Lleida railway line, on the alluvial deposits of the Cinca River. The geological hypothesis is that the iron-rich marine rocks The geological formations that emerge in the Pyrenees, uplifted when the Iberian Plate collided with the European Plate some 65 million years ago, are generating hydrogen deep underground, which rises through the earth. faults and fractures until they accumulate in layers of porous sandstone, sealed by impermeable shales.
If the presence of a significant gas pocket is confirmed, Helios expects to be able to extract hydrogen at a cost close to 0,60 euros per kilogramThis is well below the more than €2/kg that green hydrogen can cost today. This economic advantage would be a differentiating factor in positioning Spain as a European leader in golden hydrogencomplementing its already outstanding commitment to renewable hydrogen.
However, the Monzón-1 project has run up against regulatory challengesThe company obtained a hydrocarbon exploration permit in 2020, but the subsequent Climate Change Act of 2021 barred new oil and gas-related activities. The problem is that natural hydrogen doesn't fit neatly into existing legal categories, leaving the project in limbo pending further developments. mining and energy regulations "catch up" and explicitly include this type of resource.
Legal, technological and environmental challenges
The Spanish case is no exception. In most countries, the White hydrogen is not yet clearly recognized as a mineral resource. in the laws, which complicates access to public aid, drilling licenses, or specific tax frameworks. In Germany, for example, geological hydrogen is expected to be able to formally regulated by 2026, which would open the door to larger projects.
This legal loophole also hinders the arrival of private investorsWith a few exceptions, the major oil and gas companies have chosen to watch from the sidelines, letting specialized startups They take risks in the pioneering phase. Analysts like Kate Adie of Wood Mackenzie point out that the moment one of these young companies demonstrates that it can produce significant trade volumesA race to secure the best extraction zones will likely ensue.
At a technological level, locating and exploiting white hydrogen is not trivial. It often appears mixed with other gases such as helium, nitrogen, CO₂, carbon monoxide, or methane, which necessitates highly efficient separation technologies. Companies like H2SITE have developed palladium alloy membranes capable of separating hydrogen even when its concentration in the mixture is 2%, recovering up to 98% of the hydrogen present and offering a high purity gas.
These membranes function under conditions in which Other separation technologies are not viableThis makes them key components for monetizing deposits where hydrogen is not found in a nearly pure state. Furthermore, the residual gas after separation, enriched with helium or other valuable components, can in turn be converted into an additional source of incomeThis is very interesting considering that helium is considered a strategic gas, difficult to replace in many industrial and medical applications.
Furthermore, any intensive geological hydrogen extraction program must take into account the environmental and social impactsIn some scenarios, the possibility of using techniques similar to fracking to open fractures in the rock and allow water to circulate and generate more hydrogen has been raised. This raises understandable concerns about seismic risks, aquifer contamination, or landscape impactsTherefore, many experts advocate a cautious approach, with detailed studies and robust regulation before authorizing large-scale operations.
There are, however, some very suggestive concepts from a climate perspective. Some models propose inject water into iron-rich rocks at a depth of one or two kilometers to stimulate hydrogen production, while simultaneously taking advantage of the geothermal energy of the hot fluid returning to the surface. In this scheme, if it dissolves CO₂ in the injected waterThis could react with magnesium and calcium minerals and become trapped in the form of solid carbonates (limestone)That is, a system capable of producing hydrogen and sequestering carbon dioxide at the same time.
Apart from these more experimental approaches, the actual projects currently under consideration—such as Bavaria, Nebraska, Mali, or Aragon—are focused for now on take advantage of existing natural accumulations with drilling techniques already mastered by the gas industry, combined with new geological modeling tools that help identify the areas with the greatest potential.
If these types of systems are confirmed as renewables on a human scale —that is, if it is observed that the deposits are replenished as the gas is produced—, natural hydrogen could cease to be seen merely as a carrier manufactured from other sources and become, strictly speaking, a low-carbon primary energy sourceThat is precisely the great conceptual revolution that many researchers consider unstoppable.
Everything suggests that the role of native hydrogen in the energy transition will depend both on scientific and technological advance (better understand the generation mechanisms, design reliable prospecting methods) as well as the support of public policies And it depends on the industry's willingness to make a long-term commitment to a resource that, until a couple of decades ago, wasn't even mentioned in energy textbooks. If these pieces align, the "eternal fires" that fascinated the ancients could become one of the discreet but crucial pillars of the energy system of the future.
