Sweetch Energy, this Breton start-up at the dawn of a new energy revolution

Maybe, in Silicon Valley, Sweetch Energy is already worth billions of dollars. By finding a way to profitably generate electricity caused by the encounter between seawater and river water, thanks to their difference in salinity, this start-up hopes in any case to disrupt France’s energy mix, and even the planet… “ While the most optimistic expectations predict that the share of current renewable energies will not exceed 50% of total world electricity production by 2050, osmotic energy could increase this share to more than 65%. », Assured its managing director and co-founder Nicolas Heuzé. For now, however, Sweetch Energy remains a small, still cautious Breton deep tech company.

Renewable and permanent energy

The adventure began in 2013. That year an article appeared in a British magazine Nature entitled “Giant osmotic energy conversion measured in a single transmembrane boron nitride nanotube” (1). Under this somewhat barbaric title, Lyderic Bocquet and his team of researchers from the University of Lyon reveal a revolutionary technology for producing electricity from the exchange of ions between waters with others. other salinity.

“Every year, almost 30,000 TWh [30.000 milliards de kWh, NDLR ] of osmotic energy – a capacity greater than the world’s electricity demand – is released by deltas and estuaries around the world “says a fluid physics expert. Part of this clean, renewable energy, which is more permanent unlike wind or solar energy, can be taken advantage of.

Since the 1950s, scientists have emphasized its potential but no one has been able to make a profit. In the early 2010s, Lyderic Bocquet drew inspiration from biology and cellular channels to study the effects of flow within a nanotube crossing an impermeable membrane that separates saltwater and fresh water. ” We realize that with this technology and with these materials, the current produced is a thousand times more intense than the methods used until now to recover osmotic energy. “, explains one who is now director of research at CNRS and professor at ENS.

Industry stage

In search of the right idea in the field of water and renewables, one investor, Pascal Le Melinaire, was intrigued by this article. He met Lyderic Bocquet and bought his patent. Convinced that he had a “game changer” there, he decided in 2015 to create a start-up with Nicolas Heuzé and Bruno Mottet in Rennes. ” In the long run, we want to do something around the sea and renewable energy. As Bretons, we often look at this huge, very powerful, vast galaxy… At Sweetch, we put together our three favorite topics: the fight against climate change, deep technology and the sea ”summarizes Nicolas Heuzé, a former financial director who worked for MakeMusic, Paradigm, Galileo Partners, Bionersis and Medincell.

In the Rhône delta, where the water of the river mixes with the sea. It is here that the exchange of ions between waters with different salinity makes it possible to generate osmotic energy.© Hans SILVESTER/RAPHO/GAMMA

Once the project is found, it needs to be refined. Under the leadership of Bruno Mottet and with the help of Lyderic Bocquet, a core of scientists worked hard to develop membranes and electrodes capable of optimizing the amount of energy as much as possible. The goal? Reaching the lethal threshold of 100 euros per MWh below where energy is available, then 50 euros, close to the current costs of onshore wind power and photovoltaics.

So the moment of truth has come for Sweetch. “ Our membrane called Inod, based on biosourced materials, is twenty times better than what exists to date and almost ten times cheaper. This is why we have started the development stage of the industry “, Nicolas Heuzé announced without revealing the specific ingredients of his miracle recipe. The company has grown from five to twenty people a year and will reach approximately forty employees by the end of 2022.

A first factory on the banks of the Rhône

The most recent major recruitment to date is that of Edouard Billet, an Arts et Métiers engineer, who is responsible for setting the stage for large-scale development of products (membranes, electrodes) and installations (portable, portable). one and movable production modules). It is known that it will still take about 100,000 m² of modules to produce 1 GWh, the equivalent of a nuclear power plant… ” We are working with the National School of Industrial Creation to imagine the harmonious blocks that fit into the landscape “said the engineer.

Last February, Sweetch Energy signed its first industry contract with Compagnie Nationale du Rhône (CNR), the concession company for nineteen hydraulic power stations installed on the largest French river, generating 14 TWh on average. per year, i.e., 3 .5% of the country’s electricity consumption. ” Our goal is to deploy a pilot plant by the end of 2023 a few tens of KWh, then to increase its power “, says Nicolas Heuzé. In the meantime, CNR will test the prototype at its Center for behavioral testing of hydraulic structures.

Faced with the decline in hydraulic energy production in the Rhône associated with global warming, we decided to use osmotic energy a few years ago. But we decided in 2017 that it wasn’t profitable. Just three years later we came across an article talking about Sweetch Energy and we contacted them. said Frédéric Storck, Director of Energy Transition and Innovation at CNR.

Model of an osmotic power plant in the Rhône delta, project carried out by the Compagnie Nationale du Rhône together with Sweetch Energy.

Model of an osmotic power plant in the Rhône delta, project carried out by the Compagnie Nationale du Rhône together with Sweetch Energy.© DR

The Rhone -based company will provide equipment, water intakes, pipes and energy evacuations made by the first demonstrator. The latter should be approximately 20 meters long and be placed on the edge of the Rhône delta at Port-Saint-Louis or Barcarin. “ Eventually, Rhône’s osmotic production should reach between 3 and 4 TWh, i.e., almost twice the annual consumption of the city of Marseille and almost a third of France’s potential. “, the manager hopes.

Hurry up

Supported by three original funds (Demeter, Go Capital and Future Positive Capital), Ademe, BPI, as well as two business angels (Dominique Gaillard, ex-Ardian, and Fabio Ferrari, ex-Symbio), Sweetch Energy has now 5 million euros in capital and 4 million in financing. ” We will raise 30million euros in the coming months but in the long run, of course, we will need more to thrive throughout the territory and abroad, says Nicolas Heuzé. Fully invested in his mission, he wanted to “deploy osmotic energy as soon as possible across the planet to deal with climate emergencies”.

It would be great to create a French and European industrial champion of osmotic energy, but the French ecosystem is still far from allowing start-up projects to go fast as time goes on. If this is not possible, unfortunately we will go elsewheres, ”he warned. In the hope that Sweetch’s first large-scale project with CNR will allay those fears.

(1) Giant osmotic energy conversion measured in a single transmembrane boron nitride nanotube.

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