In a discovery that could revolutionise the clean energy landscape, researchers from the University of Oxford, Durham University, and the University of Toronto have outlined a roadmap for finding and extracting natural, or “white,” hydrogen from beneath the Earth’s crust.
This naturally occurring hydrogen, long overlooked, could provide a zero-emissions energy source capable of powering human civilisation for millennia, without the carbon footprint associated with fossil fuels or the high energy input required for green hydrogen.
What Is White Hydrogen?
This is a follow-up article that Haush recently published about White Hydrogen. White hydrogen is molecular hydrogen (H₂) found naturally in the Earth’s subsurface. Unlike “green” hydrogen, which is produced through electrolysis powered by renewable energy, or “grey” and “blue” hydrogen, which are derived from methane or coal, white hydrogen occurs geologically and can, in theory, be extracted directly with minimal environmental impact.
This form of hydrogen has often seeped unnoticed into the atmosphere or been mistaken for an industrial byproduct. However, with mounting pressure to decarbonise global energy systems, scientists are now taking a serious look at how to harness this hidden resource.
The Geological Conditions for White Hydrogen
The international team of geoscientists has developed a geological blueprint to locate white hydrogen deposits. Key findings identify the following geological conditions as most favourable for its presence and accumulation:
-
1. Ultramafic Rocks (Peridotite and Serpentinite):
These rocks, rich in iron and magnesium, are crucial. When water infiltrates them, a chemical reaction called serpentinization occurs, releasing hydrogen. Areas with large volumes of these rocks are prime targets.
-
2. Active Fault Zones and Fractures:
Faults allow water to percolate deep into the Earth, catalysing serpentinization. They also create pathways for hydrogen to migrate and accumulate in underground reservoirs.
-
3. Low-Permeability Cap Rocks:
To trap hydrogen underground (much like oil or gas), impermeable layers such as claystones or salt domes must overlay the hydrogen-generating zones to prevent its escape.
-
4. Stable Geologic Settings:
Regions with low seismic activity are more likely to preserve hydrogen accumulations over geologic time. The preservation of gas depends on an undisturbed subsurface.
-
5. Oxidation-Free Environments:
Hydrogen reacts readily with oxygen and other oxidants. Thus, reducing (oxygen-poor) subsurface environments are essential to prevent the hydrogen from being chemically consumed before it can be extracted.
-
6. Heat and Depth:
Temperatures between 50°C and 200°C, typically found at depths of 1–5 kilometres, are optimal for the geochemical reactions that produce hydrogen.
Best Strategies for Extraction
Extracting white hydrogen will likely resemble natural gas drilling, but with modifications:
- Exploration Wells: Initial drilling will require detailed geological surveys and magneto telluric or seismic imaging to identify potential pockets of hydrogen.
- Horizontal Drilling and Fracturing: In areas with diffuse hydrogen production, horizontal wells may maximise exposure to reactive rocks. Fracturing may enhance water infiltration and hydrogen release.
- Pumping and Separation: Once extracted, hydrogen can be separated from co-produced gases using membrane or pressure swing adsorption technologies. Purity levels may vary based on geology.
- Recycling Water: Reinjecting water into reactive rock formations could allow for continued hydrogen generation, turning some sites into quasi-renewable sources.
Global Potential
Preliminary studies indicate that continental interiors, mid-ocean ridges, and old cratonic regions (such as parts of Africa, Australia, and North America) could host vast hydrogen reserves. For example, Mali’s Bourakébougou field has already demonstrated commercial quantities of natural hydrogen.
If exploited responsibly, white hydrogen could provide a near-limitless supply of clean energy with minimal emissions and without the heavy energy requirements of artificial hydrogen production.
The Road Ahead
While promising, white hydrogen is still in its early stages of exploration. Challenges such as regulatory approval, large-scale production, environmental concerns, and market adoption must be addressed. Nonetheless, the strategic roadmap laid out by the Oxford-led team provides a clear scientific foundation for tapping into this natural clean energy source.
As the world looks to decarbonise and diversify its energy portfolio, white hydrogen might just be the buried treasure that helps fuel a sustainable future.
Sources: Smith, N., Etiope, G., Lollar, B.S., et al. (2024).
Natural Hydrogen in the Earth’s Subsurface: Geologic Controls and Exploration Strategies.
Nature Geoscience. https://doi.org/10.1038/s41561-024-01489-z
The post White Hydrogen: The Untapped Clean Fuel Beneath Our Feet first appeared on Haush.