A clean energy source may be lurking beneath mountain ranges

Mountain ranges could be a potential source of clean energy in the form of as-yet untapped hydrogen. While previous research has suggested this “geologic” hydrogen could be found underground, researchers have only recently turned to mountains as a possible store.

“Certain minerals react with water and can generate hydrogen like a free green energy source,” says Frank Zwaan at the Helmholtz Centre for Geosciences in Germany.

There are vast amounts of such minerals on Earth, but they are mainly found deep below the surface in a layer known as the mantle, he says, where they don’t come into contact with water. But during the formation and uplift of mountain ranges, some mantle rock can be brought close to the surface, where it can react with water in a process called serpentinisation.

To get an idea of the potential for hydrogen formation, Zwaan and his colleagues modelled the uplift process, looking at how much mantle material reaches areas where there are optimum temperatures and enough circulating water for this to occur. Their results support the idea that large quantities of hydrogen could be generated under mountain ranges.

Serpentinisation also occurs at mid-ocean ridges – some think it drove the origin of life – but hydrogen formed there is unlikely to be trapped, says Zwaan. That is because the temperature is lower than 122°C (252°F), and any trapped hydrogen will be “eaten” by bacteria, but under mountains it is possible to drill down to where the temperature is higher.

“Nothing wants to live there, so it’s perfect for the hydrogen to be preserved,” Zwaan told a meeting of the European Geosciences Union in Vienna last week. “And there might even be another option, to drill into what you can call the hydrogen kitchen – the area where the hydrogen is generated.”

The model results are supported by early findings from studies of some mountain ranges. For instance, Gianreto Manatschal at the University of Strasbourg, France, has confirmed there is hydrogen production under the Grisons area of the Alps in Switzerland. But how much there is remains to be seen, he told the meeting. “Our research is just at the very beginning,” he said.

There is also hydrogen seeping up from below the northern Pyrenees, reported Alexandra Robert at the University of Toulouse, France. This research, too, is at an early stage.