500MW French offshore wind farm nears completion

The 496MW Dieppe-Le Tréport offshore wind farm, in the English Channel, is owned by a consortium including Sumitomo Corporation, Banque des Territoires, and Ocean Winds – itself a joint venture between Engie and EDP Renewables.

The project company Éoliennes en Mer Dieppe Le Tréport (EMDT) has been set up by the consortium to develop the project.

The site will comprise 62 Siemens Gamesa turbines whose foundations are being installed by DEME’s installation vessel Innovation, which is transporting the jackets from Cherbourg Port to the site and installing them in 63m steel piles already there. These will support the turbine towers.

An offshore substation designed and built by Atlantique Offshore Energy has already been installed at the site with Nexans finishing the installation of the two 225kV export cables linking it to the French grid.

Onshore, construction of the operations and maintenance base at the Port of Dieppe is nearing completion, with delivery expected in 2026 to support long-term servicing of the wind farm.

Sound reduction

Underwater noise has been kept to a minimum during the heavier works, such as pile driving, thanks to a passive acoustic monitoring (PAM) system by Sercel, which provided a custom version of its QuietSea system.

The system uses microphones (hydrophones) to listen for marine animal sounds such as whistles, clicks and mutterings, detecting them and locating them in real time and continuously.

It then sends an alert to the people on the job, who can make operational decisions on the basis of the alerts.

While not a noise reduction technology, it provides the data required to prompt any mitigation actions such as the use of bubble curtains or quieter piling methods.

“We are proud to mobilize our underwater acoustic expertise and high-quality monitoring technologies to support France’s offshore wind ambitions,” said Jérôme Denigot, CEO, Sercel. “Our flexibility in offering a customized QuietSea solution to meet EMDT’s needs and our commitment to delivering operational excellence were key to QuietSea’s successful performance on this project.”