Natural Hydrogen: A Low-Cost, Low-Carbon Alternative for a Net-Zero Carbon Future

Most hydrogen used today is produced from fossil fuels, primarily natural gas, through processes like steam methane reforming. These processes are carbon-intensive and release large quantities of CO2, making them unsuitable for a net-zero future.

Green hydrogen, produced through electrolysis powered by renewable energy, and blue hydrogen, produced with carbon capture and storage (CCS), are considered clean alternatives. However, these methods are costly, and green hydrogen faces challenges due to the intermittency of renewable energy sources and the large-scale infrastructure required.

Discovery of natural hydrogen

Recently, researchers have reported hydrogen seeps and vents in various locations worldwide, and the first commercial production of natural hydrogen has begun in Mali. The Bourakébougou field in Mali has been producing hydrogen since 2012 and currently supplies electricity to around 4,000 homes. This discovery has led to increased interest in the possibility of harnessing native hydrogen on a larger scale.

Forms and origins of naturally occurring hydrogen

Hydrogen occurs in different forms within the Earth’s crust:

Dissolved gas: Found in groundwater, especially near hydrocarbon fields.

Gas in inclusions: Trapped in minerals during crystallization.

Free gas: The most promising form for commercial exploitation, found in association with tectonic features, volcanic gases, and hydrocarbon deposits.

The origins of natural hydrogen are still not fully understood but are believed to be linked to geological processes such as serpentinization (a reaction between ultramafic rocks and water), radiolysis (dissociation of water by radiation), and thermal decomposition of hydrocarbons.

Commercial viability of native hydrogen

While native hydrogen holds promise as a low-cost, low-carbon energy source, several challenges remain in its commercial exploitation:

Replicating the Mali case: The Bourakébougou field produces nearly pure hydrogen, but the production rate is relatively low. To meet global energy demands, thousands of wells would need to be drilled. Scaling up production would require significant investment and technological advancements.

Resource estimates: The U.S. Geological Survey estimates there could be as much as five trillion tonnes of natural hydrogen globally, which could theoretically meet the world’s energy needs for centuries. However, these estimates are highly uncertain, and further exploration is needed to confirm the presence of commercially viable reserves.

Production costs: Early estimates suggest that native hydrogen could be produced at a cost of less than 1 USD/kg, making it competitive with grey hydrogen (produced from fossil fuels without CCS) and cheaper than green and blue hydrogen.

Learning from natural gas production

The exploration and production of natural gas and hydrogen both require similar processes for extraction and transportation. However, hydrogen’s unique properties, such as its tendency to leak and its low volumetric energy density, present challenges for storage and transport.

Large-scale underground storage of hydrogen, similar to natural gas, may be necessary to manage supply and demand. However, only salt caverns have been found suitable for hydrogen storage so far, limiting the geographic areas where hydrogen can be stored.

While natural hydrogen has the potential to be a game-changer in the transition to a net-zero carbon future, uncertainties remain. More research and exploration are needed to determine whether native hydrogen can be produced at a scale and cost that makes it competitive with other forms of clean energy. Furthermore, public and private sector support will be crucial in advancing the technology and infrastructure needed to exploit natural hydrogen resources.

For more detailed insights, please refer to the full research paper “Natural (geologic) hydrogen and its potential role in a net-zero carbon future: Is all that glitters gold?” by Aliaksei Patonia, Martin Lambert, Ning Lin, and Mark Shuster, published by the Oxford Institute for Energy Studies.