For decades, the Earth's subsurface held an energy secret that science barely suspected: vast reserves of pure hydrogen, formed by natural geological processes, awaited discovery deep within the crust. In the last two years, this secret has begun to emerge with enough force to reshape the global debate on the energy transition.
So-called white hydrogen, also referred to as natural or geological hydrogen, is not industrially produced. Unlike other types of hydrogen, it already exists in nature, stored underground. Its extraction works similarly to that of natural gas, but with a fundamental difference: while burning natural gas releases greenhouse gases, white hydrogen generates only water.
How it forms
Researchers from the universities of Oxford, Durham, and Toronto have developed a geological formula to identify deposits of white hydrogen. Three key elements are necessary for their formation:
- An underground hydrogen source
- Reservoir rocks capable of storing gas.
- Natural seals that prevent the dispersal of the resource.
The most common geological processes that generate this hydrogen include:
- Serpentinization: a reaction between water and rocks rich in iron and magnesium at great depths.
- Radiolysis: the breakdown of water molecules by the natural radioactivity of rocks.
- Pyritization: process associated with the transformation of ferrous minerals under specific pressure and temperature conditions
In early 2025, simulations of plate tectonic processes showed that rocks pushed closer to the surface during mountain formation could be critical accumulation points. Researchers identified mountain ranges stretching from the Alps to the Himalayas as promising targets.
Where reserves have already been found
The most emblematic discovery happened by accident. In 1987, during drilling for water in Bourakébougou, Mali, reserves of almost pure hydrogen (98% concentration) were found. Industrial production began in 2012 and, since then, it has supplied approximately 4,000 homes in a region that previously lacked electricity.
This case served as proof of concept. The search accelerated. Today, the main sites of interest mapped in the world include:
- At least 30 states in the United States
- Pyrenees and Alps (Europe)
- Himalayas (Asia)
- France and Albania (discoveries announced in 2024)
- Spain: Helios Aragón company claims to have located a reservoir containing more than 1 million tons.
The USGS (United States Geological Survey) estimates that there are approximately 5 trillion tons of hydrogen in underground reservoirs around the world. According to researcher Geoffrey Ellis, "a recovery of just a few percent would still supply the entire projected demand of 500 million tons per year for hundreds of years."
The competitive advantage of cost
Here is the most powerful argument for white hydrogen. Comparing production costs as of March 2024, according to Rystad Energy:
| Type | Estimated cost |
|---|---|
| Grey hydrogen (natural gas) | Less than US$2/kg |
| Green hydrogen (renewable electrolysis) | US$4 to US$6/kg |
| White hydrogen (geological extraction) | US$ 0,50/kg |
The difference is significant. While green hydrogen faces cost barriers that still limit its competitiveness, white hydrogen, if extracted on a large scale, would operate with a cost structure close to that of conventional natural gas, without CO₂ emissions.
Brazil in the equation
The country possesses geological features that are generating increasing interest. The main areas of interest mapped to date include:
- Parnaíba Basin (Maranhão and Piauí): Hydrogen initially detected as a secondary component in conventional gas wells; reassessment identified independent systems, with igneous intrusions accelerating chemical reactions underground.
- Ceará and Rio Grande do Norte: areas with geological potential under study
- Maricá (RJ): Drilling confirmed the presence of hydrogen generated by radiolysis.
Preliminary estimates indicate that Brazil can reach up to 15 million tons of hydrogen per year through geological extraction, corresponding to approximately 4% of global demand projected for 2050.
From a regulatory standpoint, the country has made progress. In August 2024, the legal framework for low-carbon hydrogen was enacted, creating the Special Incentive Regime for Low-Carbon Hydrogen Production (Rehidro), with tax benefits valid for five years starting in January 2025.
Real challenges that cannot be ignored.
Enthusiasm has its counterbalance. The IEA rated white hydrogen production technology 5 out of 9 on its technology readiness scale, signaling that there is still a considerable way to go before full commercial viability. The main challenges identified are:
- Insufficient mapping: the geological processes that govern the generation and accumulation of the resource are still poorly understood.
- Early-stage technology: large-scale extraction and processing methods are not yet developed.
- Uncertain environmental impact: Hydrogen in the subsoil sustains biogeochemical processes and microbial ecosystems; its uncontrolled extraction could generate imbalances that are still unknown.
- Specific regulatory gap: The current legal framework for hydrogen in Brazil does not specifically address geological hydrogen, requiring supplementary regulation.
- Need for geophysical and geochemical studies: EPE points out that the reserves already identified need technical validation before any large-scale investment.
What does white hydrogen actually represent?
White hydrogen does not replace green hydrogen, nor does it solve the challenges of decarbonization on its own. But it opens a new front: the possibility of accessing clean energy with a near-zero carbon footprint and potentially very low extraction costs.
For countries with geological wealth and energy ambitions, such as Brazil, this new chapter in the hydrogen economy deserves strategic attention. Science points the way. What is needed now is to rigorously follow the evidence, invest effectively, and implement appropriate regulation.
