How much hydrogen awaits us underground?
In the 1990s, Barbara Sherwood Lollar descended into the Kidd Creek mine in northern Ontario, which cuts more than three kilometers into the ancient root of North America. There her team of geochemists found water that had been confined underground for more than a billion years. This ancient brine turned out to be a habitat…
In the 1990s, geochemists from the University of Toronto discovered water trapped underground for more than a billion years in the Kidd Creek mine, located in northern Ontario. This ancient brine was found to provide a habitat for microbes that feed on hydrogen produced through reactions between the water and the surrounding rock.
Recently, researchers revisited the data collected from 35 boreholes at the mine over a span of more than a decade. They found that these boreholes consistently released an average of eight kilograms of hydrogen per year. Extrapolating this finding to the mine's approximately 14,000 boreholes, the team estimated that around 140 metric tons of hydrogen is flowing unused out of the mine's vents each year.
While this amount is not game-changing, it represents a potential source of zero-carbon fuel for the mine's operations if captured and harnessed. Hydrogen fuel as a power source is promising, but its production typically generates substantial greenhouse gas emissions and requires more energy than the gas contains. However, accessing "geologic hydrogen" from underground reservoirs could change the equation.
Hydrogen is produced when water molecules are split by chemical reactions with iron-rich rock or, in the case of Kidd Creek, by the radioactive decay of other elements. Exploration efforts worldwide have been launched to search for hydrogen, with companies like HyTerra and Koloma in the US Midwest investigating ancient oceanic rocks associated with hydrogen production.
The US Geological Survey estimates that trillions of tons of hydrogen are produced within Earth's crust. If a small fraction of this could be recovered, it could potentially meet global hydrogen demand for centuries. Despite the promising potential, no commercially viable reservoir of hydrogen has been found yet, and public data on discoveries remains limited due to competitive pressures and investment-seeking behavior.
The research from Kidd Creek adds to the growing evidence that natural hydrogen generation and migration are genuine geological processes.
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