That’s because the site 55 kilometers (34 miles) northwest of Mali’s capital Bamako was the first place on earth powered by natural hydrogen — pure gas seeping from the earth, like crude oil or methane. The phenomenon is so anomalous that, until recently, few geologists had given it much thought. In 2011, Montreal-based Hydroma Inc. unplugged a water well near Bourakébougou cemented up in 1987 after the air rising from it caused an explosion. The exhalations turned out to be 98% hydrogen, which was then burned to provide electricity to the village.
That series of events seems to defy conventional geochemistry. Hydrogen is one of the most reactive elements — one reason it combines so readily with carbon to make fossil fuels. As a result, pure hydrogen is often assumed to be vanishingly rare in nature. Its role is so overlooked that gas chromatography — the process that chemists use to work out the composition of gaseous mixtures — typically uses hydrogen as a carrier material, making it impossible to detect in samples from underground wells.
A growing wave of discoveries is now challenging that conventional wisdom, just as hydrogen manufactured from water and renewable energy looks set to disrupt fossil fuel’s role in a host of industrial sectors. Aside from Bourakébougou, wildcatters have found seeps of natural H2 in Oman, New Caledonia, Canada, Russia, Australia, Japan, Germany and New Zealand.
Deposits in France could lead to the country producing 3 million metric tons a year, according to one recent report — roughly a third of the green hydrogen that the European Union wants to be manufacturing by 2030. Hyterra Ltd., an Australian company exploring for geologic hydrogen in the US, believes it can produce the element for $1 a kilogram — prices at which it might start to compete with natural gas. One 2020 study estimated that total global outflows of natural hydrogen might come to 23 million metric tons a year or more.
A switch into natural hydrogen might represent the perfect way for the existing petroleum industry to decarbonize — shifting skills in geology and tapping underground fluids to a green fuel of the future.There are just two problems with this promising vision.The first is that we understand next to nothing about natural H2. Crude oil extraction dates back to antiquity, and geologists hypothesized it came from decayed organic matter in the 18th century. Drillers worked out that it got trapped in folded underground rock formations long before John D. Rockefeller turned crude into big business. That scientific understanding — and the wealth of knowledge that has built up since — vastly reduces the cost of exploring for hydrocarbon deposits.
With natural hydrogen, we are in the dark. Scientists are divided about how it is even produced, with most theories centering on emergence from deep below the earth’s crust, bacterial activity, or chemical processes. Seeps often appear to be associated with unusual circular depressions in the ground, known as “fairy circles,” but it’s not well understood exactly why these form.
Until such questions are solved and underground reservoirs are mapped out, it’s going to be challenging for hydrogen startups to take on the giants of the energy industry. Hyterra’s Kansas and Nebraska prospects might be an attractive option as feedstock for the fertilizer consumed so readily in the Great Plains — but any plant set up to exploit the resource will want to know whether the wells will keep producing for 20 years or two months. That’s still not clear.
The other issue is related. That estimate of 23 million tons a year sounds like a lot — but in energy terms, it’s paltry. The EU alone hopes to be consuming 20 million tons a year of manufactured green hydrogen by 2030, and even that is barely enough to slake the world’s fossil-fuel appetites. In energy terms, 23 million tons of hydrogen represents about 2.76 exajoules — similar to the amount of natural gas we consume every week.
It’s early days for natural hydrogen, so don’t be too dispirited. No one has really been looking for this stuff until now, and predictions about the availability of mineral resources are almost always underestimates. (In 1919, the US Geological Survey predicted that country would start running out of oil in two to five years.)
Rich reserves of natural H2 may yet become the 21st century’s equivalent of the oilfields of the Persian Gulf, Siberia and Texas. As with fusion energy, however, you’d be brave to bet on a revolution this side of 2050.
