Among the most promising innovations rising to meet this challenge is osmotic power—a clean energy source that could simultaneously power and optimize desalination, the process of removing salt from seawater. As highlighted by the World Economic Forum (WEF) in its 2024 report on emerging technologies, osmotic energy membranes offer a unique opportunity to harness naturally occurring chemical gradients between saltwater and freshwater to produce electricity, while dramatically reducing the energy footprint of water purification. 

So how does osmotic power work, and what does it mean for the future of low-carbon desalination? 

The Science Behind Osmotic Power 

Osmotic power, sometimes called "blue energy" or "salinity gradient power," is generated by mixing saltwater with freshwater. This mixing releases energy due to the difference in salt concentrations—a process driven by the fundamental principle of osmosis. 

Osmosis is the natural movement of water across a semipermeable membrane from an area of lower solute concentration (freshwater) to an area of higher solute concentration (saltwater). In an engineered setting, this gradient can be harnessed to drive turbines or create electrical charges using specialized membranes. 

There are two main approaches to harvesting this energy: 

1. Pressure Retarded Osmosis (PRO): In this method, freshwater passes through a membrane into a chamber containing pressurized saltwater. The resulting increase in volume and pressure can turn a turbine to generate electricity. 

1. Reverse Electrodialysis (RED): This method uses a stack of alternating membranes that allow either positive or negative ions to pass. As ions flow from the saltwater to the freshwater side, they generate a voltage that can be collected and used as electric power. 

Both approaches require advanced membrane technologies that can selectively transport ions or water while resisting fouling (clogging), maintaining structural stability, and operating efficiently at scale. 

Pilot Projects and Global Interest 

While the concept of osmotic power has been studied for decades, it's only in the last few years that technological advances in membrane materials, nanofluidics, and membrane engineering have made it viable at pilot scales. 

Norway: A Global First 

The world’s first osmotic power plant opened in Norway in 2009, spearheaded by the energy company Statkraft. Though it was ultimately shut down in 2013 due to high membrane costs and limited efficiency, it proved that the basic principles could work at scale and sparked global interest in further R&D. 

Netherlands: REDstack Pilot Plant

The Netherlands is home to one of the most active osmotic energy research communities. A pilot plant on the Afsluitdijk—a dam separating the saltwater Wadden Sea from the freshwater IJsselmeer—has been testing RED technology since 2014. The project, known as REDstack, has shown continuous progress in improving energy yields and reducing costs. 

China and Singapore: Coupling with Desalination 

Asia, home to some of the world’s most water-stressed mega-cities, is now leading efforts to integrate osmotic power with low-carbon desalination. In China, researchers are exploring how salinity gradient energy can partially offset the energy demand of conventional reverse osmosis (RO) desalination. In Singapore, where land and freshwater are limited, institutions like Nanyang Technological University https://www.ntu.edu.sg/newri/research-focus/membrane-technology  are advancing membrane-based systems that purify water and recover energy at the same time. Source

Sweetch Energy: Turning Saltwater Into Sustainable Power 

Based in France, Sweetch Energy is a deep-tech company developing a breakthrough clean energy solution: osmotic power. This renewable source taps into the natural energy potential created when freshwater meets seawater—typically at river mouths and estuaries. The salinity difference between the two types of water creates a pressure gradient, which can be used to generate electricity—reliably and without emissions. 

Sweetch Energy’s approach centers on its proprietary INOD® (Ionic Nano Osmotic Diffusion) technology, which uses specially engineered nanofluidic membranes. These membranes are made from biodegradable biomaterials and allow ions to move more efficiently across the membrane, significantly increasing the energy yield. Unlike intermittent sources like wind or solar, osmotic power is available 24/7, making it a viable candidate for continuous, baseload power production. 

The company is currently building its first demonstration facility on the Rhône River in Southern France, designed to prove the scalability and economic viability of its solution. Backed by over €40 million in funding, Sweetch Energy is aiming to expand internationally and position osmotic energy as a key player in the future renewable mix—particularly in coastal and water-stressed regions where access to both fresh and salt water is abundant. 

With zero noise, emissions, or visible infrastructure, Sweetch Energy's system could provide clean power to urban areas, industrial zones, and remote coastal communities—without environmental disruption. 

Why Water-Stressed Regions Are Watching 

Desalination has long been the go-to solution for regions facing water scarcity, especially in the Middle East, Australia, and coastal parts of Africa and the Americas. However, traditional desalination is highly energy-intensive, often relying on fossil fuels, which makes it expensive and environmentally taxing. 

Osmotic power offers a dual benefit: 

• Energy Recovery & Supply: It can recover energy from brine waste (the concentrated saltwater left after desalination), which would otherwise be discarded. This energy can be fed back into the desalination process, making it more efficient. 

• Freshwater Production with a Lower Carbon Footprint: By reducing reliance on external energy sources, osmotic membranes could make desalination significantly greener—especially when combined with renewable energy sources like solar or wind. 

According to the WEF, advancements in two-dimensional nanomaterials and ion-selective membranes are pushing the performance of osmotic systems into commercially viable territory. This could be a game-changer for coastal cities and island nations that are energy-constrained and highly vulnerable to climate impacts. 

The Innovation Frontier: Smarter Membranes, Lower Costs 

At the heart of this progress lies innovation in membrane technology. Traditionally, osmotic membranes suffered from issues such as low water permeability, short lifespan, and susceptibility to fouling. But that’s changing. 

Modern membranes use graphene oxide, MXenes, and other nanostructured materials that allow for better control over ion and water transport. These materials are not only more efficient, but they also have improved durability and reduced fouling tendencies—making them suitable for long-term use in complex water systems. 

Additionally, researchers are developing multi-functional membranes that can both desalinate water and recover osmotic energy in a single step. These membranes could pave the way for next-generation water treatment plants that are energy-neutral—or even energy-positive. 

Challenges and Outlook 

Despite the promise, several hurdles remain. Cost remains a major challenge, especially for membrane manufacturing and system integration. Scaling up from pilot plants to industrial-scale facilities also requires regulatory support, investor confidence, and clear performance benchmarks. 

Moreover, site selection is crucial. Osmotic power systems require access to both saltwater and freshwater sources, limiting them to specific geographies—typically estuaries, river deltas, or desalination discharge zones. 

That said, the growing urgency of climate adaptation, coupled with strong tailwinds in materials science and sustainable infrastructure investment, is pushing osmotic power into the spotlight. As membrane performance improves and costs fall, osmotic power may become a central piece in the clean water and clean energy puzzle. 

Conclusion 

Osmotic power is not just an academic curiosity—it’s a real, emerging solution at the intersection of water and energy sustainability. As noted by the World Economic Forum, osmotic-energy membranes are among the most promising innovations with the potential to reshape how we produce both clean water and clean power. 

For nations and cities facing mounting water stress, especially in arid and coastal regions, the coupling of low-carbon desalination and osmotic energy recovery offers a compelling vision of the future—one where fresh water flows without draining the planet's energy reserves. 

The journey from lab to large-scale implementation is still ongoing, but the tide may be turning in favor of this ocean-powered innovation. 

This article was thoughtfully coordinated and researched by a member of the Supertrends team, with the help of AI technology to bring you the most insightful and accurate information.