Ancient rock formations older than dinosaurs are being investigated for solutions to Australia’s biggest green energy problem.
Geoscience Australia has identified thick salt deposits in the Adavale Basin in outback Queensland as having the potential for underground hydrogen batteries.
The project has the potential to provide electricity to millions of homes in eastern Australia and could help address pressing issues. renewable energy storage gap.
The Adavale Basin, located below the towns of Quilpie, Blackall and Charleville, is the world’s largest underground freshwater reservoir. Great Artesian Basin (GAB).
When Geoscience Australia’s $31 million drilling project came to an end, the question residents wanted answers to was whether their only reliable source of water would be at risk.
“On Demand” Underground Batteries
Although it was first discovered in 1958, geologists consider the Adavale Basin to be “underexplored” and notoriously difficult to study.
The Adavale Basin lies beneath the Great Artesian Basin and the Basin of Galilee in Queensland and is difficult to access. (Provided by: Geoscience Australia)
Buried beneath the Eromanga Basin and the Galilee Basin (two other large rock formations that are part of the broader GAB), there is no trace of the Adabare Basin on the surface.
It also contains the only rock salt layer found in eastern Australia, which may be thick enough to store hydrogen energy deep in the Earth’s crust.
Known as the Borie salt deposit, Geoscience Australia’s head of advice, investment, attraction and analysis Mitchell Bouma said it could be used to create containers such as artificial batteries.
“By melting that rock salt, we can store hydrogen gas, compressed air, etc. inside the melted cave.”
he said.
“You can make something like this.” [hydrogen gas] You pump it into the cave, and you basically have this on-demand battery underground. ”
Storage of hydrogen gas in underground salt caverns has been used overseas for decades, with the first facility in Teesside, UK, operating since 1971.
Geoscience Australia collected rock core samples from the Addavale Basin. (Provided by: Geoscience Australia)
Mark Bunch, an independent energy geoscientist at the University of Adelaide, said there was “huge potential” for this type of storage.
“Because it’s so big, we’ll go underground.”
he said.
“We can store all kinds of industrial gases and other chemicals in huge tanks above the ground, but we can also do it on a much larger scale. [hundreds of cubic kilometres] If you go underground. ”
In the United States, Advanced clean energy storage hub Two salt caverns being developed in Delta, Utah, will each be used to store a working capacity of 5,500 tons.
The company, a joint venture between oil giants Chevron and Mitsubishi Power, estimates that it would take more than 40,000 shipping containers’ worth of lithium-ion batteries to produce the megawatt-hour equivalent of one cave.
The hinterland near Blackall is touting the potential for storing hydrogen energy underground. (ABC News: Chris Gillette)
Dr Bunch said a few man-made caverns within the Adavale Basin would be enough to power 20 million homes per day, based on Brisbane’s average household demand.
depth perception
To assess the potential for storing hydrogen in salt caverns in the Adavale Basin, geologists drilled a three-kilometre-deep borehole into the Bolly salt deposit in November, breaking the Australian Institute of Geosciences depth record.
They collected 976 meters of solid rock core, more than 500 rock chips, and several groundwater samples.
Hydrogen gas could be stored in caves created by partially dissolving salt deposits. (Provided by: Geoscience Australia)
Buuma, who managed the project, said underground energy storage is significantly cheaper than above-ground alternatives because there are no “above-ground infrastructure costs.”
A single cave has the potential to store around 6,000 tonnes of hydrogen or around 100 gigawatt hours of energy, the equivalent of around 50 of Australia’s largest superbatteries.
Development of the Adavale Basin is left to industry while Geoscience Australia carries out the research. (Provided by: Geoscience Australia)
However, some residents living above the caves are less enthusiastic about the energy potential and are concerned about the possibility of disaster.
Blackall Tambo Shire Mayor Andrew Martin, who represents around 1,900 residents, said he was wary of anything that could threaten the area’s only permanent water source.
“That’s the precautionary principle.”
he said.
“One increase in pressure in the Great Artesian Basin, one movement of subterranean plates, one catastrophe somewhere, somehow becomes unbelievable.”
Quilpie, Blackall and Charleville lie directly above the Adavale Basin. (Provided by: Geoscience Australia)
However, Dr Bunch said injecting hydrogen gas into underground salt caverns was unlikely to damage the basin, given how salt and gas interact.
The key to safely storing gas is maintaining the correct pressure. Inside the tank, too low a pressure can create a dangerous vacuum, and too high a pressure can cause an explosion.
But Bunch said that underground, salt would become a “toothpaste-like substance” that naturally adapts to pressure changes and prevents rocks from moving, even in the “worst-case scenario” where the wrong pressure causes rocks to fault.
“This is not a big problem because the salt can move freely.”
he said.
“In the scenario [of a fault]the salt moves to fill the space, shrinking and being drawn in. ”
Dr Bunch said the move would spread the impact and prevent further damage to other rocks, noting that this would occur about two kilometers below groundwater used for drinking water and agriculture.
Agriculture is one of the industries that relies on the Great Artesian Basin as a major water source. (ABC News: Chris Gillette)
“I don’t see that as a scenario that will happen,” he said.
“This is a different scenario than storing gas in other types of rock, which can be more brittle.”
Geoscience Australia said it would use the samples to analyze mineral and groundwater resources in the area, with initial results expected to be released mid-year.
But Mr Martin said he wanted to see more evidence to ensure future exploration of the Addavale Basin was in the best interest of the local community.
“We cannot guarantee that this has been absolutely safe since time immemorial.”
he said.
“Let’s take the community with us, or we’ll have constant anxiety about what they’re doing to our lifeblood.”