White hydrogen – Switzerland joins the scramble for ‘clean oil’
The discovery of a natural hydrogen deposit in France could revolutionise the world’s energy supply. Switzerland is joining the search for this renewable energy source that releases no greenhouse gases when combusted. But all that glitters is not gold.
Hydrogen is considered a key element in the energy transition. It could replace petrol in cars and kerosene in aircraft, helping to bring about carbon-neutral mobility. But there is a catch: producing it gives off climate-damaging emissions. More than 90% of the hydrogen generated worldwide comes from fossil sources, mainly methane. Alternatives do exist, such as hydrogen obtained from renewable energy, but they are still expensive.
Interest is thus turning to naturally occurring hydrogen and the possibility of extracting it from deep below the Earth’s surface. Start-ups in the United States, Australia and Spain have already launched drilling projects and the recent discovery of deposits in FranceExternal link shows that this gas is not as rare as previously thought. Switzerland may also have reserves of natural hydrogen, and the first surveys carried out have shown promising results.
Here is everything you need to know about natural hydrogen, its characteristics and its potential as a fuel of the future.
How is natural hydrogen formed?
Earth produces hydrogen continuously through chemical reactions, mainly the oxidation of ferrous minerals and water radiolysis (that is, the decomposition of water molecules as a result of natural radioactivity). These reactions release hydrogen molecules (H2), which are usually present in combination with other elements, for instance oxygen in the case of water (H2O). The hydrogen rises to the surface or builds up in underground deposits.
How do natural and synthetic hydrogen differ?
The properties and chemical composition are the same and, in both cases, it is an odourless and highly flammable gas. The difference lies in how it is produced: natural hydrogen, which is known as white hydrogen, is generated deep in the earth’s crust, while synthetic hydrogen is created through chemical and industrial processes.
While the combustion of hydrogen gives off no emissions, producing it releases CO2 insofar as synthetic hydrogen is obtained from fossil fuels. It is then called grey hydrogen. If it is produced in a plant that captures and sequesters the emitted carbon, the hydrogen is instead called blue hydrogen.
Hydrogen can also be obtained by electrolysis, a process that uses electricity to split water molecules into their two main components, hydrogen and oxygen. When the electricity comes from renewable sources, such as photovoltaic or wind power, the hydrogen is considered to be green.
What are the advantages of natural hydrogen?
Hydrogen is both a carrier and a source of energy. Its combustion generates no CO2 and water is the only waste product. For the same mass, a hydrogen molecule contains around three times as much energy as petrolExternal link. Hydrogen can be used to power cars, trucks and aircraft that are equipped with fuel cells. The following animation illustrates how this works.
Natural hydrogen has the advantage of being a nearly inexhaustible resource. The processes that produce it are much faster – a few decades or centuries – than those that turn organic matter into oil, which take millions of years. Hydrogen deposits could thus regenerate at a rate that would ensure continuous exploitation.
The cost is also attractive and is estimated at less than US$1 per kilogramExternal link. It would therefore be cheaper than hydrogen produced from fossil sources ($0.5-1.7/kg) or from renewable energies ($3–8/kg).
“Natural hydrogen has the potential to become an important new source of energy for the whole world,” according toExternal link Geoffrey Ellis of the US Geological Survey, cited by Swiss public broadcaster RTS.
Why are people talking about this right now?
Until around a decade ago, natural hydrogen reserves were thought to be almost non-existent or inaccessible. All this changed in 2012, however, with the discovery of a deposit in Mali in West Africa. There, hydrogen is burned directly on site to generate electricity for a small village.
This discovery gave new impetus to hydrogen prospecting and, in May this year, the energy company Française de l’Energie announced the discovery of a deposit in the Lorraine region of north-eastern France. The reservoir could contain 46 million tonnes of hydrogen, the equivalent of half the hydrogen produced globally each year.
Where are the main reserves globally?
There are many regions around the world whose geology is conducive to the formation of hydrogen. This includes the presence of ferrous minerals, temperatures above 200 degrees Celsius and water seepage. In addition to the United States, Australia, France and Spain, the most promising areas are to be found in Russia, Canada, Oman, Japan and China.
Ellis believes that most of the natural hydrogen supplies are too deeply buried or too far offshore to be profitably exploited. Nonetheless, he points out, if even a small fraction of the estimated global deposits could be recovered, there would probably be enough hydrogen to last for hundreds of years.
Does Switzerland have natural hydrogen reserves?
Geological maps and chemical measurements of gases found beneath the ground suggest that natural hydrogen is present in Switzerland and the Alpine region in general. “We have found rocks that produced hydrogen in the past. Now we need to find out if there are rocks deep down that can still produce hydrogen today,” explains geochemist Eric Gaucher, co-founder of the start-up Lavoisier H2 Geoconsult.
The collision of tectonic plates, which caused the formation of the Alps, brought iron-rich rocks from the Earth’s mantle closer to the surface. Gaucher’s research in recent months in the cantons of Graubünden and Valais has shown promising results: there could be “hydrogen kitchens”, or production sites, deep below the earth’s surface. The next step will be obtaining funding for a thesis on the subject and assessing the real potential, says Gaucher.
It is early days, though, to picture Switzerland as the future “Qatar of hydrogen”, Gaucher cautions. There is scientific interest today in pursuing studies in the field, but there is so far no proof that exploiting natural hydrogen can be cost-effective in any region of the planet, except in geothermal wells in Iceland, he says.
And in any case, before hydrogen exploration in Switzerland can go ahead, the law – in particular the mining code – would need to be amended, as France did last year. In Switzerland, it is up to the cantons to decide whether to authorise this kind of prospecting on their territory. At best, the first drilling would only be able to start in seven to eight years’ time, Gaucher predicts.
A video report by Swiss public television RTS on July 22, 2023, on natural hydrogen research in canton Valais.
What do environmental organisations think?
Hydrogen is not without its challenges, warns Nathan Solothurmann of Greenpeace Switzerland. It is a volatile substance with a significant risk of leakage. In the atmosphere, it is 11 times more harmful to the climate than CO2, as he told the newspaper Le NouvellisteExternal link. Exploration, storage and transport of the gas also require infrastructure that can negatively impact the environment.
Natural hydrogen should only be used, the environmentalist believes, to replace methane in certain chemical processes, such as fertiliser production. And the idea that it could one day be used on a large scale as a fuel is a “dangerous illusion”.
Edited by Sabrina Weiss/translated from Italian by Julia Bassam.
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