Hydrogen mon amour

Imagine a future where the world's energy comes mostly from the sun and the wind. This is a goal many nations are working toward, but these sources have a natural rhythm: the sun does not shine at night, and the wind does not always blow. When the weather is calm and dark for several days in a row, the power grid faces a shortage. To keep the lights on, we need a way to store energy for those rare, difficult periods. One idea is to use hydrogen, a gas that can be made from water using electricity, stored for a long time, and then turned back into power when needed. However, making this gas, moving it, and converting it back is a process that loses a lot of energy and can still create pollution if not done carefully. Scientists are now asking a different question: instead of manufacturing this fuel, could we find it already waiting for us underground?

This question lies at the heart of a new essay by physicists Christophe Grojean and Patrick Janot, who are exploring how a massive particle collider called the FCC might power itself without relying heavily on nuclear energy. The FCC is a planned machine that will study the smallest building blocks of the universe, but it will also need a tremendous amount of electricity—about 1.3 terawatt-hours every year. While the authors argue that most of this power could come from renewable sources like solar and wind, they acknowledge that a small but significant portion might still need to come from nuclear plants. Nuclear power is clean in terms of carbon emissions, but it produces radioactive waste, which is a major concern for the public and the environment. The authors want to see if there is a way to reduce that remaining nuclear share further, and with it the associated radioactive waste, by finding a better way to handle those days when the wind and sun fail.

The authors begin by walking through the options for storing energy, treating the problem like a journey. The most efficient way to use electricity is to use it immediately when it is generated. If that is not possible, the next best step is to store it in batteries. Batteries are excellent for holding power for a few hours, such as from the afternoon until the evening, and they are very efficient at getting the energy back out. However, batteries become too expensive and heavy if you try to store power for several days or weeks. For those longer gaps, known as "dark doldrums," the authors look at hydrogen. Hydrogen can be stored in large tanks for long periods, but the process of turning electricity into hydrogen, storing it, and turning it back into electricity is very inefficient. It loses more than half of the original energy along the way.

The paper then examines the idea of making "green" hydrogen using solar power in sunny regions far away, transporting it to the collider, and converting it back to electricity. The authors calculate that this would require a massive solar farm, covering an area roughly three to four kilometers on each side, and would cost about one billion euros just for the solar panels. Even with this huge investment, the system would only recover about 20 percent of the original energy. They conclude that while this might work as a last-resort backup, it is too inefficient and expensive to be the primary solution for the collider's needs. The authors are clear that hydrogen is not a magic fuel source; it is simply a way to move energy across time or space, and it comes with a high price tag in terms of energy loss and cost.

Having ruled out the idea of manufacturing hydrogen just to power the collider, the authors turn their attention to a more surprising possibility: natural hydrogen. For a long time, geologists have ignored hydrogen found underground because they were looking for oil and gas. However, recent surveys in the Lorraine region of France have found significant amounts of hydrogen dissolved in water deep underground. In one specific borehole drilled to a depth of 3,655 meters, scientists found hydrogen in the rock layers. Some estimates suggest this area could hold up to 46 million tonnes of hydrogen. If this resource is real and accessible, it would be a game-changer because it would not require the energy-intensive process of splitting water to create the fuel. Nature would have already done the work.

The authors are careful not to call this a solved problem. They emphasize that finding hydrogen in a rock sample is very different from having a steady flow of gas coming out of a well. The key question is whether the reservoir can produce enough hydrogen every day to be useful. The current data shows that while hydrogen is present, no one has yet demonstrated an industrial flow rate large enough to power a facility like the FCC. The authors suggest that if this resource can be tapped sustainably, it could be one of the cleanest energy sources available, with a carbon footprint far lower than hydrogen made from fossil fuels. It would not produce the radioactive waste associated with nuclear power, and it would not require the massive energy losses associated with making hydrogen from electricity.

The essay proposes a practical path forward. The authors suggest that the organization behind the collider, CERN, could act as a "launch customer." By signing a long-term agreement to buy electricity generated from natural hydrogen, they could help fund the development of the industry. This would give scientists and engineers the confidence to build the necessary infrastructure, test the flow rates, and prove that the resource is real. The timeline fits well: if trials planned for the late 2020s are successful, the industry could be ready to supply the collider when it begins operation in 2048.

Ultimately, this paper is not a promise that natural hydrogen will save the day, but a call to investigate it seriously. The authors argue that we should stop assuming that all hydrogen must be manufactured by humans. Instead, we should look for the hydrogen that the Earth has been producing for millennia. They conclude that while fusion energy and other advanced technologies are still far in the future, natural hydrogen offers a tangible, immediate possibility. The challenge now is to move from hope to hard data, to measure the flow, check the carbon footprint, and determine if this "white gold" is truly a resource we can rely on. The answer is not yet known, but the authors believe it is a question worth asking, and one that could change how we power our future.