Sweetch Energy, a World Economic Forum 2025 Technology Pioneer, uses nanofluidics and biomaterials to harness osmotic energy, which is naturally generated by the difference in salinity between river water and seawater, to produce carbon-free, renewable, and non-intermittent electricity at scale.
“When you look at the current challenges in the energy field – including the pitfalls of current renewables – it ticks all the boxes,” says Nicolas Heuzé, co-founder and CEO of the French scale-up. “Osmotic power is clean, completely natural, available 24 hours a day in all coastal areas, can be turned on almost instantly and modulated very easily.”
In partnership with France’s Compagnie Nationale du Rhône, a French electricity generation company, mainly supplying renewable power from hydroelectric facilities on the Rhône river, Sweetch Energy’s OPUS-1 demonstrator facility began its testing phase at the end of 2024, validating the technology’s operation under real-world conditions, says Heuzé. Located in Port-Saint-Louis-du-Rhône, the OPUS-1 demonstrator is the first in a series of potential installations at the Rhône estuary planned for the coming decade. Collectively, these sites could deliver up to 500 MW of carbon-free electricity, enough to power more than 1.5 million people, equivalent to the population of Marseille and its metropolitan area. Sweetch Energy is also exploring other projects in France and abroad, including in the U.S., Canada and Asia, where significant osmotic resources exist.
Osmotic power systems are one of the ten emerging technologies in 2025 named in a June World Economic Forum report in collaboration with scientific publisher Frontiers. The Innovator is publishing a series of independently reported in-depth articles on the 2025 emerging trends in its FutureScope section, under a collaboration agreement with Frontiers.
Sweetch Energy’s progress in France is just the start. Osmotic power systems have the potential to generate nearly a fifth of global electricity needs, some 5,177 terawatt-hours (TWh) annually, according to the Dubai Future Foundation, which contributed to the Forum’s report.
“Globally, and particularly in salt rich areas like Australia and the Middle East, where access to brackish or seawater exceeds access to freshwater, these power systems hold huge potential for baseload energy and clean water production, says Dr. Katherine Daniell, PhD, the current Director of the Australian National University’s School of Cybernetics in the College of Systems and Society, and a contributor to the osmotic power section of the Forum’s report.
Beyond licensing processes and effective environmental and social impact assessments, there appear to be relatively few hurdles to wide adoption once sufficient financial investments are made into osmotic power systems, says the report.
From The Research Lab To Power Generation
The concept of osmotic power systems is not new. “It has been on the radar screens of academics and industrial companies since the 1950s,” says Heuzé. Each year, nearly 30,000 TWh of osmotic energy – more than the world’s electricity demand – is released by deltas and estuaries. Attempts were made in the 1970s to harness this osmotic energy, which would otherwise dissipate, but were not commercialized due to limitations of membrane performance, including inadequate flows through the membrane and insufficient power produced even in larger area systems, according to the Forum report.
But new scientific breakthroughs and material patents have increased the potential viability of osmotic power systems in recent years, Daniell said in an interview with The Innovator.
Today there are two general designs for osmotic power systems. One, called pressure retarded osmosis (PRO), uses a specially designed semi-permeable membrane that only allows water to move from a low-to high-salinity environment. The increased amount of water on one side of the membrane generates a pressure difference that can be used to drive a turbine that spins a generator to produce electricity.
Another type relies on reverse electrodialysis (RED) which uses ion-exchange membranes that selectively allow cations (positive charge) and anions (negative charge) to move to opposite sides of the membrane – the impetus being differences in the salt content between two sides of the membrane. That flow of charge directly generates electricity.
To be selective, early ion exchange methods used very small (5 picometer) pores to ensure low ionic circulation. But this meant to get to power capacity the membrane surface had to be huge and they were very expensive, so it was not scalable, says Heuzé.
To get around this problem more performant membranes were constructed from new materials, such as base of titanium oxide or bi-dimensional materials, in labs in the U.S. and China.
A team in the physics laboratory of France’s l’École Normale Supérieure directed by Lydéric Bocquet took a different approach: instead of focusing uniquely on the materials used to make the membranes it looked at nanofluidics. The first experiments use a unique nanotube placed at the intersection of two reservoirs of salt water and clear water during the ionic transport. The most important lesson learned from these experiments was to propose a different route for membrane design based on optimal osmotic transport at nanoscales, says Heuzé.
Sweetch Energy has based its work on this technological breakthrough. In a nanotube you can make the pores 100 times bigger than previous pores, which means the ions can circulate much faster, making it easier to scale, he says.
Heuzé and co-founders Bruno Mottet and Pascal Le Melinaire, all seasoned entrepreneurs, read about this breakthrough in the journal Nature in 2013 and approached Bocquet about commercializing the technology. An initial meeting between Mottet and Bocquet went well, and they started collaborating.
Sweetch Energy was launched in 2015, and the team spent the next six years working to develop a new membrane that could replicate the efficient nano diffusion created in the lab and do it with materials that were low cost, sustainable and easy to industrialize.
The result was a new type of nanoporous membrane: INOD (Ionic Nano Osmotic Diffusion) membrane, made from natural materials that can be found everywhere on earth and are widely used in other industries, says Heuzé. Combined with proprietary electrode systems, these membranes combine high ion selectivity and high ion transport to achieve unmatched performance, he says.
INOD membranes are now being used in the first pilot site to produce osmotic energy in the Rhône delta. Pictured here are the connection points for the pipes that channel freshwater and seawater to the side of each module. This controlled flow through selective membranes enables the generation of an ionic current — the core mechanism behind converting osmotic energy into electricity. This interface is critical to the proper operation of Sweetch Energy’s INOD system, ensuring the water flows for energy production.
The objective is to produce electricity 24 hours a day and reach a cost of €100 euros per megawatt hour by 2030, which is competitive with main baseload sources like nuclear, coal and gas (except gas in the U.S.) and cheaper than other renewable energy sources coupled with batteries, Heuzé says.
“The key here is to mix technology performances with low-cost production,” he says. “We are developing a new industry and putting together a supply chain to source all the material at low cost,” says Heuzé. “We can replicate a supply chain and manufacturing capacity in all regions in the world starting here in Europe.”
Sweetch Energy says it thinks the right way to expand is to forge partnerships like the one it has with Compagnie Nationale du Rhône. It says it is seeing a lot of interest from potential partners in Asia. “We are looking for partners ready to build the future of osmotic power with us,” he says.
Sweetch Energy has so far raised €50 million from investors that include Crédit Mutuel Impact, Go Capital, Demeter Investment Managers, Axeleo Capital, Future Positive Capital, EDF Pulse Ventures, and Compagnie Nationale du Rhône), as well as French and European institutions BPI, ADEME, and the European Innovation Council. The company works closely with leading French research institutions, notably the team of Bocquet (CNRS, ENS). In addition to being named a Forum Tech Pioneer the company has received numerous awards, including the Grand Prize of the Hello Tomorrow Global Challenge.
Other companies are also trying to scale up osmotic energy. An EU-funded Danish company, SaltPower, founded in 2015, already generates power using the super-concentrated salt solutions that well up from geothermal sites. In a form of circular economy, the Mega-ton Water System Project in Fukuoka, Japan extracts energy from a seawater desalination plant’s output of highly saline solution left over after purified water is produced, says the Forum’s report.
In addition to power generation, techniques such as RED have been shown to potentially be relevant to producing purified water, and recovering lithium, nitrogen and carbon dioxide (CO2) from the water employed in the process.
Transforming Water Into A Strategic Resource Platform
The most compelling opportunity lies in the technology’s ability to integrate energy production with water management, the Dubai Foundation says in the Forum report.
Utility companies might develop hybrid renewable systems that combine osmotic power with wind, solar and hydro technologies, creating more adaptive and resilient energy networks. Coastal and estuarine communities could particularly benefit from decentralized energy solutions that enhance local energy resilience.
As the technology matures, says the report, it could reshape global approaches to resource management. Osmotic power technologies could enable new approaches to desalination while recovering critical resources like lithium during the process. This could create interconnected systems where water management, energy production and resource extraction become deeply integrated.
“Imagine a future where water-intensive industries view water not as a waste stream, but as a strategic resource platform,” says the report. “Communities might develop economic models that transform geographical constraints into opportunities. These industries could reimagine their infrastructure to generate multiple forms of value – energy, purified water and recovered materials – from each interaction with water.”
To realize benefits at scale, “the most innovative organizations will recognize osmotic power as more than an energy technology – it represents a potential platform for re-imagining how water-intensive industries create economic value, says the report. “A desalination plant could evolve from a cost center to a multi-purpose resource generator, simultaneously producing energy, purified water and recoverable minerals – transforming infrastructure from a linear process to an adaptive, value-creating ecosystem.”
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