One day, in the rocky soil of Lorraine, a former coal-mining region near the French-German border, scientists inserted a small probe through a borehole half a mile deep into the earth’s crust.
The frothing in the water table below was an exciting find: champagne-sized bubbles that suggested a potentially huge supply of so-called white hydrogen, one of the cleanest fuels in nature.
“Hydrogen is magic – when you burn it you release water, so there are no carbon emissions that would warm the planet,” said one of the scientists, Jacques Pironon, lead researcher and professor at the University of Lorraine. “We believe we have discovered one of the largest reserves of natural hydrogen in the world.”
The discovery by Mr. Pironon and another scientist, Philippe de Donato, both members of France’s prestigious National Center for Scientific Research, caused a stir in France, where the government has pledged to become Europe’s leader in clean hydrogen.
There are still many questions about the find, including its exact size and how best to extract the gas. But it has added to the trail of clues elsewhere in the world that a holy grail of clean energy may lie underground, just waiting to be captured.
Governments and companies around the world are relying on hydrogen as a cornerstone in the fight against climate change. A multibillion-dollar industry, supported by billions of dollars in subsidies and private investment, has emerged to support the production of hydrogen that could theoretically replace fossil fuels to power factories, trucks, ships and planes, potentially cutting about half of emissions that are warming the planet.
However, the commercial production of hydrogen involves splitting water into hydrogen and oxygen, a process that requires energy. The use of fossil fuels produces greenhouse gas emissions, the result is called gray hydrogen. Using renewable electricity from wind turbines and solar panels to produce so-called green hydrogen is cleaner but more expensive.
Natural hydrogen, also called white hydrogen because of its purity, could be a game-changer, scientists say, as a potential source of clean energy continuously produced by Earth. Hydrogen storage occurs when heated water meets iron-rich rock. According to the US Geological Survey, even a small portion of these deposits could provide enough clean energy for hundreds of years.
“If they confirm this discovery, it would be very significant and have a big impact on society,” Geoffrey Ellis, a geochemist at the US Geological Survey and a global expert on hydrogen, said of the French discovery. “There are many other places in the world where similar finds could be made, and people are looking at this because it could be really significant.”
In Lorraine, scientists said their tests suggested that 46 million to 260 million tons of natural hydrogen could be lurking beneath coal mines abandoned in the 1970s when France switched to nuclear power. For comparison: around 70 million tons of hydrogen are produced commercially worldwide every year.
Natural reserves of hydrogen have recently been discovered in parts of the United States, Australia, Africa, Russia and elsewhere in Europe. It’s not uncommon to find hydrogen while drilling for gas or oil, but in the past companies ignored such discoveries due to low demand.
Researchers didn’t give much credence to white hydrogen until a chance discovery in 1987 in Bourakébougou, a small village in Mali, when a worker accidentally set a well on fire by lighting a cigarette over it. The source was found to contain natural hydrogen, which is now being used to power businesses and homes after a local entrepreneur hired a petroleum company to extract the gas.
“People haven’t looked for natural hydrogen for years because everyone was focused on drilling for oil and gas,” said Julien Moulin, president of Française De l’Énergie, a clean energy company with Mr. Pironon and Mr. de Donato is expected to test and develop white hydrogen projects. “But it feels like we’re at the beginning of a new dynamic,” he said.
Française De l’Énergie’s main business is extracting methane gas from coal seams and converting it into clean electricity for industry in the region. With the discovery of hydrogen, the company will intensify its efforts to explore and extract it, Moulin said.
“You’ve got the cake – now the question is, how do you eat it?” he said. “You have to create the tools to develop this resource and that will be the work of the next few years.”
The efforts in Lorraine reflect the broader enthusiasm in the clean fuels industry about natural hydrogen. The growing understanding that Earth is its own hydrogen factory has sparked a mini-gold rush among researchers and start-up energy companies looking for a find.
In Australia, Gold Hydrogen, an independent energy company, is exploring for natural hydrogen near Adelaide after unearthing historical documents from two oil wells drilled in the 1930s that contained large amounts of high-purity hydrogen in the area. Bill Gates is among investors in the United States who have funded Koloma, a Colorado company searching for hydrogen in a vast geological fissure in the Midwest. In Europe, small energy companies from Spain, Switzerland, the Nordic countries and elsewhere are scouring the Earth’s crust.
Whether white hydrogen lives up to the hype remains to be seen. So far, the finds range from potentially huge finds that can take years to verify, like the one in Lorraine, to small or extremely deep accumulations that may not be economical to search, Ellis said. The question remains whether it is an unlimited source of clean fuel. Big oil companies like TotalEnergies of France have not invested and appear to be waiting to see how things develop.
Then there are the costs. Although the United States and Europe have committed billions to subsidize the development of green hydrogen using renewable energy, none of it goes toward supporting white hydrogen production.
And white hydrogen producers need to keep an eye on the final price of their gas. Although green hydrogen costs about $5 per kilogram to produce – more than twice as much as gray hydrogen – the U.S. Department of Energy is promoting a program to reduce the price of green hydrogen to $1 per kilogram within a decade .
In Spain, a start-up company called Helios Aragón is developing a project to produce natural hydrogen in the Pyrenees that it claims can match or even exceed that price.
“The No. 1 question is what the costs will be,” said Marco Alverà, chief executive of Tree Energy Solutions (TES), a company that wants to produce and import clean hydrogen into Europe. For natural hydrogen to be competitive, “it depends on many factors, including the pressure the gas is under, the temperature and the type of rock you’re drilling through,” he said.
Meanwhile, Europe is building a large network of pipelines that could deliver manufactured hydrogen to factories and gas stations. The hope is that white hydrogen could one day flow through them.
If all goes according to plan in Lorraine, new drilling will begin next year with an advanced probe that will collect gas samples from up to 1.8 miles underground – deeper than the length of the Golden Gate Bridge – to determine the size of the hydrogen deposit to test, with the aim of producing natural hydrogen by 2027 or 2028.
Mr. Pironon and Mr. de Donato have high hopes. When they began searching for methane gas left behind in the coal mines, the deeper they went they discovered hydrogen instead. Half a mile deeper, they found higher concentrations of hydrogen than have been reported anywhere else in the world, Mr. de Donato said.
“We may have a real hydrogen factory under our feet,” he said. “That’s cause for real excitement.”