Summary
Highlights
Arnout Everts introduces himself as a geoscientist with a PhD in Earth Sciences and over 30 years of experience in the oil and gas industry, and more recently, renewables like geothermal energy, CO2 storage, and natural hydrogen. He explains his interest in natural hydrogen's potential to facilitate the energy transition, especially its role as a clean, emission-free energy source for storing excess renewable energy and decarbonizing industrial processes.
Everts notes that the interest in natural hydrogen has been spurred by its potential as a clean energy source. Historically, hydrogen was believed to be scarce in its pure molecular form due to its reactivity. However, historical reports and recent discoveries, such as a well in Mali (Bougou 1) that has been powering a nearby village since 2007, have renewed interest. Geological surveys suggest the Earth's crust emits significant quantities of hydrogen, potentially 23 million tons annually, suggesting a larger potential than previously thought.
A significant challenge is that most natural hydrogen emissions are highly diffused, occurring as natural seeps at low flow rates, unlike the trapped, high-pressure reservoirs found in oil and gas fields. Exploiting these diffuse sources might lead to low production rates, making commercialization difficult. Other occurrences include hydrogen absorbed in coals, similar to coal-bed methane. However, these also typically yield low flow rates and require dense drilling grids, potentially leading to environmental concerns like water disposal and the need for fracking in less permeable rocks.
Hydrogen is the lightest and most reactive element, tending to bind with oxygen to form water or carbon to form methane. This reactivity means that over long migration times, hydrogen is likely to be lost. Therefore, potential hydrogen traps would need to be located very close to its source to avoid significant dilution.
Everts describes hydrothermal alteration of ultramafic rocks (iron and magnesium-rich silicates), like those found on the seabed. When these rocks interact with water, a process called serpentinization oxidizes the silicates and releases hydrogen. While common on the seafloor, trapping hydrogen in these settings is challenging. Discovering such rocks buried under other formations, yet still in contact with water and capable of trapping hydrogen, is a rare geological setup required for significant accumulation.
Other processes generating hydrogen include radiolysis, where radioactive isotopes in rocks split water molecules into hydrogen and oxygen. This process is limited by the scarcity of highly radioactive rocks. Another source is lower crustal degassing, where hydrogen trapped deep within the Earth is emitted as rocks from the mantle and lower crust move closer to the surface. Both processes are not universally common and finding exploitable concentrations is difficult.
Everts emphasizes that high flow rates are crucial for commercial viability of any gas project. This allows for fewer wells, higher production, and secure delivery volumes for industrial consumers. The current findings in Mali report very low flow rates, equivalent to about three barrels of oil per day, which is minimal compared to typical oil or gas wells. Similar discoveries in France, Spain, and Australia have only shown 'shows' (indications of gas inflow) but no material recovery to the surface, highlighting the challenge of achieving commercially viable flow rates.
Historically, drilling focused on oil and gas, and existing gas detection kits cannot detect hydrogen. However, with growing interest in natural hydrogen, service companies are developing specialized detection tools for exploration wells. These advancements are expected to lead to more reports of natural hydrogen worldwide, although not necessarily in large, easily exploitable quantities.
Widespread hydrogen exploration, particularly from diffuse sources like natural seeps or coal-absorbed hydrogen, would require extensive drilling and high water production. This water, often saline and contaminated, would require costly treatment and disposal, posing significant environmental challenges. These issues, similar to those faced in coal-bed methane and shale gas extraction, need careful consideration to ensure environmentally acceptable development.
Everts discusses the French hydrogen find in the Lorraine Basin, noting that while intriguing, it presents significant challenges. The hydrogen is absorbed in coal seams, similar to coal-bed methane, and flow rates are likely low. Furthermore, the gas is not pure hydrogen, but a mix with methane, requiring costly separation. Producing from deep coal seams is technically challenging and environmentally contentious due to potential fracking and dense well grids. Commercialization will likely depend on the value of methane, not just hydrogen.
Three conceptual settings for exploitable hydrogen include: natural seepage settings (like Mali) where deeper-generated hydrogen is focused into fault zones; hydrogen absorbed in coals (like France) requiring stimulation and extensive drilling; and proper traps where hydrogen is accumulated at higher pressures (currently unproven on a large scale). The latter, if discovered, would allow for significant, localized decarbonization.
The future of white hydrogen largely depends on discovering truly trapped, high-pressure accumulations. If found, these could decarbonize specific industrial sites. More likely, small-scale production, similar to Mali, could provide energy to remote areas, replacing less environmentally friendly alternatives like diesel generators. Everts expresses skepticism about the current 'hype,' suggesting it's driven by smaller companies seeking to attract investors and 'flip assets' rather than possessing the financial and technical capabilities for full-scale commercialization.