Hydrogen gas produced by geological processes beneath Earth’s surface has been touted as a promising clean energy source. A brand new study provides the primary solid evidence that it could possibly be a practical and commercially viable option for decarbonizing the grid.
Hydrogen is an energy-dense fuel that produces only water when burned. But today, the overwhelming majority of commercial hydrogen is manufactured using fossil fuels in an energy intensive process, negating its green credentials. While there’s hope renewable energy could at some point power the method and supply a reliable source of green hydrogen, that technology continues to be a good distance from business viability.
Recently though, there was growing excitement about the potential of vast natural hydrogen reserves stored deep underground. Several large deposits have been discovered and estimates suggest that trillions of tons of the gas could possibly be sitting beneath our feet.
To this point, those estimates have been almost entirely theoretical, based largely on near-surface measurements, proxy data, and extrapolation slightly than direct observations. Studies have also typically brushed over the complexities of storing and distributing hydrogen gas, which must be kept at high pressure or extremely cold temperatures.
A brand new study, published in PNAS, firms up the numbers. The authors track the discharge of natural hydrogen over an 11-year period from a mine in Canada and conclude the location produces enough hydrogen to generate 4.7 million kilowatt-hours of energy annually. That’s enough to power a couple of hundred homes or an industrial facility and suggests probably the most promising approach to natural hydrogen could possibly be to make use of it where you discover it, they are saying.
“We present another vision for the hydrogen economy that may address a number of the current challenges arising from the main focus up to now, that has been largely based on transportation of hydrogen over long distances from source location to markets,” the authors write. “Calculations from this study site show that the quantity of locally generated energy has economic value for each industries and communities situated on hydrogen-producing rock.”
The brand new study focused on the Kidd Creek mine near Timmins, Ontario where researchers had collected 11 years of hydrogen discharge data from 35 boreholes between two and three kilometers below the surface.
The authors found that, on average, these boreholes were pumping out between 1 and three liters (0.04 to 0.1 cubic feet) of the gas per minute. Across all of Kidd Creek’s nearly 15,000 boreholes, the researchers estimate the location releases greater than 140 tons of hydrogen per yr.
The hydrogen at Kidd Creek is primarily produced through a process called serpentinization, during which water reacts with iron-containing minerals deep within the crust. Greater than 70 percent of the continental crust has the potential for this sort of hydrogen generation, the researchers say, suggesting the mine, and its hydrogen output, could also be removed from unique.
For the reason that gas is already being vented during routine mining, capturing it might require relatively modest investment, the researchers say. And hydrogen is not the only resource on offer. Sites that produce hydrogen also are likely to release methane and helium at predictable rates.
Based on the quantity of hydrogen at Kidd Creek, the researchers estimate the location might be producing 4,200 tons of methane and 140 to 280 tons of helium. The latter could possibly be particularly priceless, given its critical role in cryogenic technologies. With recent supply crunches, further exacerbated by the Iran war, prices have been within the range of $100,000 per ton.
Capturing the gas isn’t at all times easy, the authors note. Underground microbes can devour it before extraction. It may require significant investment after capture to separate the gases.
But many communities sitting on hydrogen-producing rock could have a priceless renewable energy source just beneath their feet. And the economic case for exploiting it’s looking increasingly solid.