French drillers may have found huge hydrogen deposit – Ars Technica

On the outskirts of the small town of Fallsweiler in eastern France, there are three nondescript cottages. One of these temporary structures has recently become a hive of activity due to the constant flow of visitors, including scientists, journalists and the public.

The shed is located above a well that was first drilled in 2006, and houses a gas measurement system called SysMoG, which was originally developed to determine underground methane concentration. While the instrument detected almost pure (99%) methane at a depth of 650 meters and searched below, the borehole led to an unexpected and surprising discovery: hydrogen in high concentration. “At an altitude of 1,100 metres, the concentration of dissolved hydrogen reaches 14 percent. At a depth of 3,000 metres, the estimated concentration can reach 90 percent,” said Jacques Péronon, director of research at the GeoRessources Laboratory at the University of Lorraine.

Based on estimates of the methane resources and hydrogen concentration discovered so far, scientists have predicted that the Lorraine region in eastern France, of which Fallsweiler is a part, could contain 46 million tons of white or naturally produced hydrogen. This would make it one of the largest known hydrogen deposits in the world.

Look for something else

This remarkable discovery was not the goal of the project called Regalor. Instead, the goal was to determine the feasibility of methane production in the Lorraine region and record the presence of traces of other gases. “Our original research was to study carbonate deposits in northeastern France. This was important because Lorraine was one of the largest coal-producing regions in France,” Peronon said.

According to Perronon, after coal production in Lorraine stopped in 2004, a company called Francaise de Lanergie proposed sourcing methane from the region’s vast coal fields. The regional government then requested the expertise of Laboratoire GeoRessources to determine whether such a project was realistic.

“As part of this project, we have developed a new instrument with a Franco-Swiss company called Solexperts. It consists of a patented SysMoG probe that can be lowered by a logging crane to depths of 1,500 metres.

The probe is equipped with a membrane that allows gases to be separated from the water in which they are dissolved. As a result, gases can be pumped to the surface for analysis. This is a new concept. In the past, determining the presence of underground gases required bringing water from the ground to the surface and vacuuming the gases from the water for analysis.

To detect and characterize the presence of methane gas, a 1,250-meter-deep well that was drilled more than 15 years ago was monitored. At a depth of 600 metres, the team found that 99% of the gas dissolved in the water was methane, while only 1% was hydrogen, which, according to Péronon, is not out of the ordinary.

“Later, we had the opportunity to make measurements down to the bottom of the borehole. We observed a continuous increase in hydrogen from 600 to 1,250 metres. We discovered that the hydrogen concentration was about 20 percent at the bottom of the borehole.

What is the deposit size?

Soon, the researchers will begin making measurements in three more wells at similar depths to understand whether the hydrogen concentration remains high as you move sideways from the original well location. He said: “If the concentration is similar, the next step, which is being discussed with the authorities, will be to drill a hole 3,000 meters deep to verify the evolution of hydrogen concentration at depth.”

A deeper well could also lead to another surprise. “Besides knowing the level of hydrogen concentration, we will also know whether hydrogen is present in dissolved form or in a gaseous state at these depths,” Perronon said.

This study can also shed light on the source of this hydrogen. According to Peronon, there are two hypotheses, one of which is related to the presence of siderite. “Hydrogen can be produced by the reaction between water and siderite, which is made of iron carbonate. We consider that siderite can be oxidized by water molecules to produce hydrogen. Oxygen then combines with iron to produce iron oxide.

According to Perronon, another hypothesis links its presence to the chemical processes that form coal, which can also produce hydrogen, along with the release of methane.

Given that Lorraine has one of the largest coal beds in the world and boasts 6 km of deposits, Perronone and fellow researcher Philippe Di Donato are on board with the new tests confirming estimates of the underground hydrogen underpinning the three harmless barns. stands up.

With hydrogen becoming the fuel of the future due to its promise of net-zero emissions, the discovery of massive amounts of so-called “white hydrogen” could be a shot in the arm for the transition to clean energy.

Dhananjay Khedilkar is a journalist based in Paris.