Green energy: abundant scientific research

If the ecological transition cannot be achieved without a change in our practices, technological innovations will also play a key role. In terms of green energy, many research projects could bear fruit. Here are three examples.

Osmotic energy

Electricity could be produced in all estuaries. In 2013, at the Institut Lumière Matière in Villeurbanne (Rhône), the physicist, professor attached to the Ecole Normale Supérieure (ENS) Lydéric Bocquet and his colleagues rediscovered an energy known since the 1950s but somewhat neglected: osmotic energy.

Concretely, when you put waters with different salinity levels in contact, the salt naturally circulates to balance itself. It is in fact made up of sodium charged positively with electricity and chlorine charged negatively. Place a membrane that only lets sodium ions pass through, you create a natural electric battery. The problem then lies in the cost and efficiency of the membranes. In 2015, Bocquet founded the start-up Sweetch Energy with entrepreneurs crazy about applied sciences. In less than ten years, she managed to create a membrane that is both biosourced and economically accessible. A first large-scale osmotic energy production pilot is in place on the Rhône delta.

MOFs (Hybrid Crystallized Porous Solids)

MOFs are also coming to the rescue of the environment. What are we talking about? metal organic frameworksor hybrid crystallized porous solids in French. They contain tiny cavities, of the order of nanometers, that is to say the size of essential molecules (O₂H₂Oh, WHAT₂etc.). Hence the selective absorption properties that interest researchers.

Chemist Christian Serre, research director at the CNRS, head of the Institute of Porous Materials in Paris (ENS, ESPCI, PSL University), recently elected to the Academy of Sciences, has devoted a large part of his career to these materials, which he compares to “molecular sponges”He has created hundreds of variations and multiplied their applications in the field of green energy (hydrogen production, heat transfer, membranes for batteries or fuel cells) and the environment (capture or recovery of CO₂air pollution control, etc.). His fundamental research is of interest to industrialists, with whom he works. In 2021, he also co-founded the start-up SquairTech, which specializes in indoor air quality.

Hydrogen

Hydrogen is a key lever in the energy transition: it could partly replace hydrocarbons and its use does not pollute. But today it is mainly produced from natural gas, a process that releases CO₂. A sustainable option to this method is water electrolysis, or the splitting of water molecules (H₂O) into oxygen molecules (O₂) and hydrogen (H₂). This requires catalysts, such as platinum, a rare metal that is too expensive for large-scale use.

But, explains chemist Vincent Artero, formerly of the “rue d’Ulm”, research director at the Grenoble Interdisciplinary Research Institute, “Producing hydrogen, without platinum, with solar energy, is possible. We just need to take inspiration from nature, in particular microalgae.” For years, Vincent Artero and his team have been mimicking the active sites of enzymes capable of producing hydrogen, such as hydrogenases. Ultimately, the idea is to produce a “solar fuel” cheap, explains Mr. Artero, who already works with manufacturers like Engie.