In the scramble for clean energy that could help us transition away from fossil fuels, scientists may have found a new power source – and it could be lurking in our mountains. Using advanced simulations, a German team of researchers think they’ve found vast reserves of hydrogen gas (H2) produced by millions-of-years-old rocks.
As a power source, H2 is more sustainable than fossil fuels, which release greenhouse gases and cause climate change by trapping heat in the atmosphere. That’s because, on its own, H2 produces water instead of greenhouse gases. But the problem is that H2 isn't usually produced on its own: currently, producing synthetic hydrogen often requires using fossil fuels… ironically.
So, the major obstacle in H2 production has been where to get it from. Geological processes can generate natural hydrogen – avoiding the synthetic production that needs fossil fuels – but the location, if any, of large, accessible reserves has remained uncertain. This new research could change that.
“Overall, we may be at a turning point for natural H2 exploration,” said Dr Frank Zwaan, lead author of the new study, published in journal Science Advances. “As such, we could be witnessing the birth of a new natural hydrogen industry.”
The research team, from the GFZ Helmholtz Centre for Geosciences in Germany, used simulations of plate tectonic processes to locate the vast reserves.
Natural hydrogen can be generated in several ways – for example, through bacteria transforming organic material, or water molecules splitting as a result of radioactivity in Earth’s crust.
But the most promising natural method for large-scale generation is through a geological process known as ‘serpentinisation’. Unfortunately, this has nothing to do with snakes – but rather how rocks from deep in Earth’s mantle react with water.
Essentially, the minerals in these rocks undergo chemical transformations, forming new minerals that belong to the 'serpentine group' – and, critically, releasing H₂ gas in the process.
The researchers think that when these rocks are found near Earth’s surface, they could create significant hydrogen-rich zones, potentially viable for drilling and large-scale H₂ production.
To get to the surface, the rocks are ‘tectonically exhumed’ through over 2,900km (1,802mi) of mantle over millions of years. This process occurs through two main mechanisms: continents breaking apart (allowing the mantle to rise), and the formation of mountains (which pushes mantle rocks up to the surface).
When the researchers modelled the two processes, they found that mountain formation created the best conditions for serpentinisation. They think that the cold environments of mountain ranges, combined with increased water circulation, could create increased volumes of hydrogen. In fact, their simulations showed that rocks emerging through mountain formations promised 20 times more hydrogen capacity than those pushed to the surface through continent rifting.
Researchers have already found indications of natural hydrogen generation in mountains including the Pyrenees, European Alps and Balkans.
The scientists behind this new study hope their findings will encourage further exploration for natural H₂ in these and other mountainous regions.
Head of the Geodynamic Modelling Section at GFZ, Prof Sascha Brune said: “Given the economic opportunities associated with natural H2, now is the time to go further and also investigate migration pathways of hydrogen and deep, hydrogen-consuming microbial ecosystems to better understand where potential H2 reservoirs can actually form.”
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