After hosting the first “world’s tidal turbine farm” in 2018, the town of Caluire, near Lyon, is preparing to experiment with a new process, also unique on a planetary scale. From the end of June, four biomimetic tidal turbines, which reproduce the movement of fish in water, will be installed in the river currents of the Rhone in order to generate electricity.
It’s a revolution in the (small) tidal stream environment, accustomed to turbine models which, like a wind turbine that captures air, use water currents to produce energy. But a company from Boulogne-sur-Mer, EEL Energywanted to bet on the works by Jean-Baptiste Drévet to imagine a new technology in the world of renewable energies.
“If the propeller principle works on land, it is more difficult to make it optimal in water, where this same process does not exist naturally, develops Franck Sylvain, general manager of the company. However, species such as the blue marlin and the swordfish manage to move, in this very dense universe, at more than 110 km/h. They do this through undulation. We thought that it was this technique that would make the machine the most efficient in the field. »
Technology that captures 50% more energy than the best propellers
And the results speak for themselves. “Our membranes have been installed for a year in the harbor of Brest, in Brittany, continues the entrepreneur. The record is extraordinary. Our machines recover 50% more energy than the best propeller turbines. »
How does it work (or rather, does it swim)? Imagine a dolphin against the tide, treading water. “On the tail of this dolphin, we have fixed a mast that goes up and down. This movement activates a dynamo to make electricity work”, illustrates Franck Sylvain.
It also highlights the ability of undulating membranes to produce “H24”. “As long as there’s water,” he half-jokes. Before quoting all the advantages: “This technology has no waste or CO2 emissions in operation, does not emit visual or noise pollution underwater or on land. In addition, there is no impact on the coast and no attack on wildlife. Unlike wind or solar power, tidal turbines do not depend on the weather. The currents are predictable, quantifiable, localized and regular. »
Caluire, privileged site for tidal turbine tests
Once installed in the Rhône, these machines will produce 400 MWh per year, the equivalent of the consumption of a hundred households. Why here specifically? “At this location, there are no passing boats or other river activities. And the current velocities are very strong [plus de 2 m/s]. What interests us is the power of the current”, specifies the managing director of EEL Energy. Difficult to gather characteristics for rivers. “In France, we have a lot of hydroelectric dams which have an influence on the kinetic energy necessary for hydrokinetic turbines. The interesting market is then at the level of the tidal currents, in the sea, or in other countries of the world”, explains Franck Sylvain.
The Hydroquest-Hydrowatt consortium, which tested its technology in Caluire for three years, has also decided to focus on the maritime development of these tidal turbines, specified the French Waterways (VNF), detailing that EEL Energy had taken over the contract concluded with this subsidiary. “As the connection infrastructures already exist, there is no civil engineering work to be planned”, underline the VNF. And to conclude: “We are delighted that the site continues to live in this way, given that the favorable conditions and the difficulty of carrying out this kind of experimentation elsewhere. We are very proud to contribute to the development of the sector by making the public domain available. »