​​Bruno Mottet, Lyderic Bocquet and team​

The duo’s cutting-edge INOD® (Ionic Nano Osmotic Diffusion) technology uses a special membrane, made from a cost-effective bio-sourced material, to harness the energy generated at the meeting point between seawater and river water. During the process of osmosis, ions travelling from the high salt concentration of seawater to the low concentration of river water via the membrane result in a charge difference that produces an electric current. “Osmotic energy takes its roots in the entropy of mixing salt into fresh water,” says Lyderic Bocquet. “Osmotic energy harvests this entropy, this chaos, into something which you can work with."  

Sweetch Energy, co-founded by Mottet and Bocquet, as well as Nicolas Heuzé and Pascal le Mélinaire, has collaborated with Compagnie Nationale du Rhône (CNR) to launch France's first osmotic pilot plant, OsmoRhône. At scale, 500 megawatts (MW) of osmotic capacity could be installed on the Rhône and eventually reduce the cost of osmotic energy from an initial EUR 150-180 per MWh to EUR 50-80 as usage increases. According to Sweetch Energy, osmotic energy production could help raise the global renewable electricity share from the projected 50% in 2050 to 65%, contributing substantially to the decarbonisation of the energy sector. 

The fight against climate change requires reducing our reliance on fossil fuels to meet the growing global electricity demand (28 000 terawatt-hours (TWh) per year in 2022). Renewable energy solutions like solar and wind can reduce this gap, but they are heavily dependent on the weather and are not always readily available. Osmotic energy, unaffected by weather conditions, has the potential to provide clean and reliable energy to satisfy global electricity demands.  

Turning a big idea into a reality

Sweetch Energy was founded after Mottet, an engineer with a passion for mining and mineral engineering, read a paper on using boron nitride for renewable energy harvesting written by Bocquet, a distinguished physicist and pioneer in nanofluidics, and flew to Canada to meet him. They first experimented with boron nitride and later titanium oxide, both of which yielded promising results and led to Bocquet filing the duo’s earliest patent applications. However, these materials were expensive to work with.

Undeterred by these setbacks, they continued researching materials for a membrane and eventually found an alternative bio-sourced material.  With their new, cost-effective bio-material, they were able to convince the French government and European Commission to recognise the potential of osmotic energy, leading to the plans for OsmoRhone. According to Mottet, their story is one of perseverance, "It'll be a massive victory for Lyderic and me, as we have been working on the subject for now 10 years”.