2023-09-11 12:13:20
This should be one of the surprise guests of the next multi-year energy programming law (PPE), currently being developed. Ignored up to now by the public authorities, because deemed too expensive and not industrially mature enough, the creation of a tidal stream turbine sector should ultimately be encouraged.
The most powerful farm in the world deployed in the raz Blanchard
In July, the Ministry for Energy Transition already announced financial support of 65 million euros from the State, as part of the France 2030 plan. It will come in addition to an electricity feed-in tariff for the development of FloWatt, a 17.5 MW pilot farm, which will be installed in Raz Blanchard, off the Cotentin peninsula in the Manche department.
With seven turbines of 350 tons each, which are 25 meters high and 20 meters wide, laid 35 meters deep with gravity foundations, it should be the most powerful ever deployed in the world.
This is not entirely a leap into the unknown. Since 2008, an experimental site has existed off the island of Bréhat in the Côtes-d’Armor. A prototype, equipped with a 1 MW turbine, even operated for several years. It was designed by OpenHydro, the subsidiary of Naval Group, a 62% state-owned company specializing in armaments.
But, in July 2018, the state abandoned the project and the sector. One month after the inauguration of the tidal turbine production site in Cherbourg! Alstom was also interested in the matter. But this was closed with the takeover of the company’s energy branch by General Electric in 2014.
The machines do not see each other
Tidal energy, which produces electricity from ocean currents, is the least well-known of renewable marine energies – we are talking more about offshore wind power, static or floating – but has many advantages, which also explains the current interest.
“It’s a renewable energy like no other. It is predictable over decades, it cannot be seen, and does not lead to conflicts of use with fishermen, because the boats do not go where the machines are installed, given the currents. These two characteristics give it enormous value”explains Olivier Guiraud, managing director of Qair Marine, the developer of FloWatt, associated with the Grenoble turbine manufacturer HydroQuest, a subsidiary of Mechanical Constructions of Normandy (CMN).
Another advantage of tidal turbines: their energy density. “It only takes 15 km2 to install 1 GW, compared to 160 km2 for offshore wind power”he says.
We understand the interest of the government, which seeks to increase the volumes of renewables as quickly as possible. After the setbacks of the sector in recent years, its promoters consider the winds more favorable today, and continue to promote industrial production in France.
A potential of 5 GW in France
In Raz Blanchard alone, the capacity would be 3 GW of tidal turbines, making it possible to produce between 11 and 13 TWh per year, or roughly the equivalent of the future EPR. In total, French potential could reach 5 GW, with that of the Fromveur passage in Finistère.
“It could even be more, with the evolution of technologies which will make it possible to capture weaker and deeper currents”, judge Olivier Guiraud, recalling that other countries are working on the subject, such as Canada or, above all, Great Britain. Globally, the market is estimated at more than 100 GW.
For FloWatt, the first tank trials will start next year, before sea trials in 2025 and commissioning, at best, in 2026, if the schedule is respected. There remains the cost of the electricity produced. Its price should be around €300/MWh, almost seven times more than for the future EDF wind farm off the coast of Dunkirk. The sector nevertheless estimates that it can go down to around €100/MWh from the first installed gigawatt.
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