A new "float out and sink" offshore wind turbine foundation design will be demonstrated at the Fécamp project in the English Channel.
The so-called cranefree gravity foundation is designed for the next generation of offshore wind farms that will be built in deep waters and with bigger turbines, and is the only foundation design that can be installed using regular towing vessels.
Seatower, the Norwegian firm that has developed the new foundations, says that it was selected for the Fécamp project because the "game-changing" design promises to cut construction costs and reduce installation risks for the offshore wind sector. The contract is the final step in the firm's objective to move the foundation design to full-scale manufacturing and deployment.
"Our technology will ease and speed up the construction of offshore wind farms at a time when cutting costs and risks is necessary to help the sector progress to more challenging project sites," said Seatower CEO Petter Karal. "Cranefree Gravity foundations are generally more cost-efficient, quicker to install and less risky than current methods that use steel foundation designs.
"They also allow for local construction, which provides welcome economic activities to the coastal communities close to the wind farms."
The Fécamp project is being jointly developed by EDF Energies Nouvelles, Dong Energy and wpd offshore and will consist of up to 83 Alstom 6 MW Haliade wind turbine units installed 13 km off the coast of Normandy.
Current project plans indicate that gravity base foundations will be used alongside Seatower's demonstration foundation.
Seatower says it will manage the installation of the demonstration foundation, which will be pulled around 13 km by a towing vessel before being positioned and subsequently sunk in a controlled manner by gradually letting in seawater. It will be outfitted with equipment that will measure wind and other parameters on the site, as well as to provide data for future optimisation of the technology.
Eiffage, the French construction giant, which is an established manufacturer of conventional, steel-based foundations for the offshore wind sector, will fabricate the demonstrator foundation at the port of Le Havre.
Seatower said in a statement that its technology will give offshore wind farm developers more control over the installation process because unlike other foundation designs, it will not require the use of specialist and weather-sensitive crane ships.
In addition, installation of cranefree gravity foundations would not require underwater piling.
Sian Crampsie
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