Fairy circles may point to underground sources of clean energy from natural hydrogen reserves

The race to replace fossil fuels has inspired researchers to explore many unconventional potential sources. Among these, natural hydrogen, which is found deep underground, is gaining attention.

It is seen as a possible building block for a cleaner energy future. Yet, it remains difficult to predict where this hidden hydrogen lies.

A recent study from the University of Vienna suggests that mysterious features on Earth’s surface, called fairy circles, could reveal the presence of these underground reserves.

The round patches, where vegetation is damaged or absent, may point the way to a sustainable energy source.

What are fairy circles?

Across many parts of the world, unusual circular patterns appear on the landscape, drawing attention from scientists and local communities alike.

These formations, known as fairy circles, can be found in regions as distant and varied as Russia, Namibia, Brazil, and Australia.

They often stand out sharply from the surrounding environment due to the presence of vast rings or depressions with sparse or no vegetation.

Despite their size – sometimes hundreds of meters across – the depressions themselves are relatively shallow, sinking only a few meters into the ground.

For decades, these circles remained a geological and ecological mystery. Researchers speculated about many possible explanations, ranging from termite activity to natural gas seepage.

Questions still remain

However, no single theory could fully account for their global presence. It wasn’t until roughly ten years ago that a significant breakthrough emerged.

Scientists discovered that these fairy circles were not just barren patches of land but active sites where natural hydrogen escapes from reservoirs deep underground.

This finding revealed a surprising connection to one of the cleanest potential energy sources known.

Still, even with this discovery, questions persisted.

The mechanisms that shaped these depressions, and the reasons their size might vary depending on the depth and pressure of hydrogen, remained largely unknown. This left both geologists and the energy sector eager for clearer answers.

Linking hydrogen and fairy circles

This information is critical for the energy industry. Natural hydrogen carries a negligible carbon footprint, making it an attractive sustainable option.

“But before expensive drilling can be carried out, we need to understand how fairy circles form, how large the deposits might be and how deep we need to drill,” explained Martin Schöpfer from the University of Vienna and NiMBUC Geoscience.

A study supported by OMV and led by Schöpfer used geomechanical computer simulations to show why hydrogen-emitting fairy circles sink.

The simulations revealed that interactions between gas, water flow, and soil create a two-step process that leads to surface collapse.

Soufflé effect explained

The team compared the phenomenon to a soufflé. Loose sediments, like sand or clay, sit above solid rock.

When hydrogen enters the sediment, it pushes water upward, uplifting the surface. Plants suffer from the altered gas mixture and die, leaving bare patches.

“You could say that the sediment rises like a soufflé, but here geomechanical processes are at work, whereas with a soufflé it is chemical processes,” explained Schöpfer. When the hydrogen flow stops, pressure drops and the sediment compacts.

“The soil compresses and subsides, similar to a collapsing soufflé,” he added.

Matching nature and models

Simulations aligned closely with real fairy circles found in Russia, Brazil, and Australia. The research showed a clear pattern: larger circles indicate deeper and higher-pressure hydrogen sources underground.

“These findings are a real breakthrough,” emphasizes Bernhard Grasemann, deputy head of the Department of Geology.

“Fairy circles could thus serve as natural signposts in the future for finding underground hydrogen sources – a potentially inexhaustible and environmentally friendly energy source.”

Hydrogen from fairy circles matters

The energy sector is closely watching these developments.

“The energy sector’s interest in natural hydrogen as a potential new energy source with a negligible carbon footprint is growing, especially in comparison to all other types of artificially produced hydrogen,” noted Gabor Tari, chief geologist at OMV.

He pointed out that natural, or white and golden hydrogen, along with orange hydrogen, may become cheaper and more profitable than traditional forms, such as black, gray, blue, pink, or green hydrogen.

This is why OMV supports basic research that explores hydrogen’s future role in energy transitions.

Next steps in research

Although promising, many questions remain. Schöpfer stresses the need for additional studies.

These may include testing different soil types, simulating pulsing gas emissions, and conducting field research to examine chemical reactions that could further influence subsidence.

If fairy circles do serve as natural guides to underground hydrogen, they could reshape global energy strategies. Unlocking this hidden source may bring the world one step closer to a truly sustainable energy system.

This could drive innovation across industries, reduce global reliance on carbon-heavy fuels, and open opportunities for affordable, clean energy.

The study is published in the journal Geology.

Featured image: A new study by the University of Vienna explains why “fairy circles” – circular areas where vegetation is damaged, as seen here in the São Francisco Basin in Brazil – subside and how their diameter is related to the depth of the hydrogen source. Credit: Alain Prinzhofer/University of Vienna

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