Claypans across Australia, which can be clearly seen from jetliners and are what some call “fairy circles,” might hold the key to natural hydrogen seeps and a new mining industry.
It could put South Australia at the heart of a new mining rush as explorers look for “gold hydrogen” to fill the fuel tanks that drive the country into a green economic future.
The Government of South Australia amended legislation in 2021 to make hydrogen a regulated substance. Part of that permitted the exploration and tapping of natural hydrogen reserves.
One clue may be the previously undesirable presence of salt pans.
“Those circular depressions are called ‘fairy circles’ by some authors, and numerous occurrences of the same type of features are observable across Australia,” CSIRO research scientist Dr Ema Frery told Cosmos.
It turns out they can result from chemical reactions triggered by hydrogen gas seeping through cracks in the bedrock below.
“In Australia, we demonstrated the existence of natural hydrogen seeps in 2021, with the exploration of some ‘fairy circles’,” says Frery.
Geoscience Australia published a map of natural hydrogen prospectivity in Australia on the basis of geological maps and a review of old wells.
Now Frery and her team are studying these hydrogen systems from potential surface seeps to the possible “kitchens” producing it in the depths.
It’s all about understanding the underground natural hydrogen process. That will help prospectors determine the extent of any national reserves.
Also in Cosmos: The Hydrogen solution
Hydrogen is the most abundant element in the universe. Here, on Earth, it’s bonded chiefly with oxygen to make water. And separating the two is an energy-intensive task.
But it appears an easy, pure source has been hiding under our noses all along.
“If you want to get going with the colour code, we call that hydrogen ‘gold’ or ‘white’ hydrogen,” Frery says, “but really, it is the hydrogen that does not need to be manufactured. It is directly coming from mother earth.”
And that may be precisely what a new green economy needs.
One kilogram of green hydrogen (produced with renewable energy) currently costs between $4 and $8 to manufacture, though prices have steadily declined. Brown, blue and black processes (using fossil fuels) cost about $2.
Simply extracting ready-formed hydrogen from the Earth could undercut both.
“This begs the following question: is Australia rich in multiple natural hydrogen potential reservoirs, or are we simply observing salt lakes?” asks Frery.
Exploration companies are now beginning to report to the Australian Securities Exchange (ASX) the presence of potentially enormous reserves in South Australia.
“In that region, the geological system seems to be ‘clean’ with more than 80 percent hydrogen discovered in some of the old wells of the Yorke Peninsula and Kangaroo Island,” Frery adds.
“But we are starting to find quite a few clues showing that this hydrogen is renewable. Some of the hydrogen we are sampling at the surface can have formed just a few days or even a couple of hours before!”
One working theory involves the radioactive decay of underground uranium and thorium which naturally occur in certain mineral deposits. This radiation can split the bonds within water molecules.
Another process involves the interactions between water and ferrous rocks, with hydrogen being a by-product of the oxidation of iron. This type of reaction is now proven to be happening at low temperatures.
“This is really different from the known hydrocarbon systems,” says Frery. “If you have the right source rocks (and we have plenty in Australia) and some water, you may keep forming hydrogen.”
Scientists examining the origins of life on Earth first stumbled on this process about a decade ago in deep undersea hydrothermal vents and mysterious naturally occurring mud “volcanoes”.
In one instance, Frery says, an attempt to find groundwater reserves in the West African nation of Mali instead stumbled upon a massive accumulation of 90 percent pure hydrogen.
“(The company) (Hydroma) started to use this hydrogen to provide electricity to a local village. Now, more than 10 years after the start of production, the source is still there, and the reservoir is not depleted at all,” she says.
In South Australia, Gold Hydrogen is this month (March) conducting a 9000 square kilometre airborne gravity-magnetic survey over the Yorke Peninsula and Kangaroo Island to refine its current best-guess estimate of a 1.3 billion kilogram reserve into a more certain figure.
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