Scientists Want to Burst Underground Gas Bubbles To Access More Helium — Will It Work?
The noble gas could get a lot greener.
When you think of uses for helium, birthday balloons (and inhaling them for chipmunk voices) may come to mind. But it’s actually a highly valued element that’s used in everything from computer chips to MRI scans in its gas and liquid forms.
Just a handful of countries supply the world’s helium, including the U.S. and Russia, by extracting it from natural gas — it forms over millions of years as the radioactive elements uranium and thorium decay in rocks below natural gas fields.
As these unstable elements gradually break down, tiny pockets of helium gas bubble up through layers of sediments, eventually coming to rest just below the surface and mixing with natural gas. After drilling or fracturing natural gas, refineries isolate the helium by cooling it to subzero temperatures.
This means that most of the world’s commercial helium is tied to natural gas production, which creates significant greenhouse gas emissions.
“[Helium] is actually connected to a really high carbon footprint,” Anran Cheng, a geochemist at the University of Oxford in England, tells Inverse.
But a new study published in the journal Nature could offer an alternative, greener source for this prized gas — and it may be right beneath our feet.
Cheng’s team at Oxford used a computer model and recent geological survey data to determine the likelihood that a given site may have a rich underground helium deposit. This technique could prove simpler and more environmentally friendly than the prevalent natural gas extraction method.
Modern helium madness
Helium is known for its buoyancy, its small molecular size, and its tendency not to react with any substance — a quality it shares with all of the other “noble” gases. For these reasons, it is often used to indicate gas leaks.
The element was previously used as a lifting gas for airships. But like today, the U.S. had a monopoly on the global helium market in the early 20th century — so after the Helium Act of 1925 banned exports of the gas, many European countries had to turn to its highly flammable cousin, hydrogen, to fill their blimps and zeppelins. (Until, of course, the Hindenburg disaster.)
It wasn’t until relatively recently that people began hunting helium for its own sake. A series of breakthroughs in medicine, computing, and communications over the last thirty years have prompted a ballooning demand for helium
Today, helium helps cool nuclear reactors and power spacecraft as they launch into orbit. Microchip manufacturing relies on helium, as do many fiber optics that help deliver internet across the globe. It’s also crucial to the medical field — helium helps MRI machines stay conductive for scans.
Nowadays, the demand for helium is beginning to outstrip global supply. And as the world transitions away from fossil fuels and toward renewable energy, we’ll need new, more sustainable ways of finding helium.
To scout out the buoyant gas, Cheng and her team designed a computer model to predict where helium might accumulate in rock layers.
Since helium and nitrogen move much faster through porous, spongy rock layers underground, understanding the geologic composition of a given area can provide vital clues as to whether or not a helium gas field might be lurking just beneath the surface.
A second vital clue: Helium often builds up alongside nitrogen. The model from Cheng’s team considers the nitrogen concentration in the groundwater around a given site. If a lot of nitrogen is present, there’s a good chance a helium deposit lurks nearby. What’s more, releasing these nitrogen- and helium-filled gas bubbles won’t emit carbon dioxide or methane into the atmosphere.
In addition to finding new helium sources, the researchers think this model could help suss out gas fields filled with hydrogen — which forms thanks to the same radioactivity that creates helium underground. Nowadays, some experts think hydrogen could serve as a promising clean fuel source.
Chris Ballentine, chair of geochemistry at the University of Oxford and co-author of the study, cautions that we still don’t know how well hydrogen is preserved underground — it could escape or react with its surroundings much more quickly than helium. But the ability to dig up these essential gases marks an important step in decarbonizing the world, he tells Inverse.
“I think the potential for the subsurface to generate hydrogen is massive,” Ballentine says.
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