A few months ago, a University of Lorraine research team led by Jacques Pironon and Philippe de Donato set out to assess the level of methane gas in the Lorraine sub-soil, an area that hosts rock formations from the Carboniferous period, about 359 to 299 million years ago.

Their goal was to make an estimate of the total amount of methane present there and see if local production was viable. However, they ended up hitting something unexpected.

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Using Solexperts’ SysMoG, a probe and method for gas measurements in deep boreholes, the group was able to assess, in an environmentally friendly way, the gas dissolved in water in rock formations up to 1200 metres in depth. That’s when they realized that they had discovered what may be the world’s largest white hydrogen deposit.

Different from its manufactured counterparts, that is, grey, black and green hydrogen, white hydrogen is a primary energy source because it is already present in that state in nature. This means that there is no need for extra energy inputs from other gases or substances.

“Following chemical monitoring of the rock strata and accompanying methane deposits, we had been surprised to find that a high proportion of hydrogen was present and that its concentration grew as we descended, reaching 20% at 1250 metres down,” the researchers wrote in a recent article in The Conversation. “Such levels allowed us to speculate that at 3000 metres below the ground, hydrogen content could exceed 90%, according to our modelling. On the basis of the gas data at 1100 metres below ground (14% hydrogen), the Lorraine deposit could contain up to 46 million tonnes of white hydrogen, which is to say more than half of the world’s current annual production of grey hydrogen.”

For comparison, Pironon and de Donato mention that the well in Bourakébougou, Western Mali, is presently the world’s only exploited white hydrogen site and its production is only 5 tonnes per year. Thus, it trails way behind the 80 million tonnes of natural gas-based grey hydrogen globally produced every year.

Modelling work carried out following the discovery is making the scientists think there is a possibility of the Lorraine white hydrogen supply being almost infinite.

They are now mapping the best ways for extracting the gas, a process that starts by proving that hydrogen is evenly distributed in a 490-square-kilometre large basin. To do this, they have deployed the SysMoG probe in boreholes near the existing one at Folschviller where they discovered the presence of hydrogen. The next step is to show that the concentration of hydrogen keeps growing at depths greater than 1200 metres.

Since there aren’t any boreholes in the Lorraine region that allow them to send a probe so deep, they are also seeking the French government’s approval to carry out a deep, 3000-metre excavation to demonstrate that the concentration of hydrogen does indeed grow further down.

“If this is the case, we will confirm the presence of an exceptional deposit of naturally occurring hydrogen, bigger than any discovered elsewhere, and we can make a first realistic estimate of its scale,” the team’s article reads. “A number of commercial and institutional partners, French and international, are interested in financing the project.”