Wind Energy – Installation Campaign
Another mobilisation campaign of the DEME heavy lift vessel Innovation at its base in Flushing has been concluded.
The deck spread welding and seafastening have been skillfully executed by the offshore mobilisation teams of APT Global Marine & Offshore Engineering in cooperation with DEME.
The Innovation has departed the Netherlands 23 May for La Rochelle, France.
Here the Innovation is due to start a monopile installation campaign on the Iles d’Yeu et de Noirmoutier offshore wind farm.
For this specific project off the French Atlantic Coast Herrenknecht’s Offshore Foundation Drilling (OFD) technology will be used for the second time.
The mechanized drilling method developed by Herrenknecht and DEME to install foundations for large-diameter monopiles was used for the first time at the St. Nazaire wind farm in 2021 and 2022.
For the new wind farm, OFD will be used to drill boreholes for 61 monopiles in the rocky Atlantic seabed between the islands of Noirmoutier and Yeu. Each monopile has a diameter of 7 meters and will serve as the foundation for one of the more than 200-meter-high wind turbines.
The new project off Noirmoutier is subject to similarly challenging weather, sea and bottom conditions as off St. Nazaire. With water depths of up to 36 meters, the monopiles will be embedded in the rocky seabed.
DEME and Herrenknecht jointly developed the drilling and installation method and are continuing their close collaboration with the second project. Herrenknecht supplies the drilling technology and provides specialized drilling personnel who are constantly on board the installation vessel in shifts during the project.
DEME is responsible for the installation of the monopiles and the MODIGA (Monopile Offshore Drilling Installation and Grouting Aid). It serves as a drilling template and enables controlled lowering using a liner, which also stabilizes the borehole.
The 73 drilled foundations for the Saint-Nazaire wind farm have already been installed using the mechanized drilling method for large-diameter monopiles developed by the two technology leaders as a world first. This reference project was fully completed entirely on schedule.
The drilling for Noirmoutier will be carried out with the 350 tonnes OFD machine also used off St. Nazaire in 2021/2022. It has a drilling diameter of 7,700 millimeters and an impressive drive power.
For the construction of the new wind farm project, the OFD machine was thoroughly overhauled by Herrenknecht, subjected to extensive functional tests with comprehensive test documentation and then transported back to Vlissingen, the home port of the installation vessel Innovation.
In addition to overhauling the machines and reusing them in new projects, Herrenknecht’s sustainability concept includes using OFD drilling technology to keep the seabed largely intact and reduce noise emissions that are harmful to underwater fauna.
The monopiles for the project will be loaded onto the Innovation in the port of La Rochelle. After the drilling process, the monopile is then inserted into the lowered liner, creating the foundation for a wind turbine.
During the installation period, expected to last around 12 months, a team from Herrenknecht will always be on board the Innovation, to control and maintain the OFD drilling machine.
After completion, the Noirmoutier windfarm will have a total output of 496 MW and generate around 1,900 gigawatt hours of electricity per year from, covering the needs of 800,000 inhabitants.
