Provence Grand Large offshore wind farm, off the coast of the Marseille region in France, is the first pilot floating wind farm in France. The project will comprise of three 8.4 MW wind turbines from Siemens Gamesa Renewable Energy, erected on pyramid-shaped floating foundations designed and built by SBM Offshore. This future-oriented floating facilities are a solution for previously unusable sea locations.

The sub components of the floating foundations were assembled at the Eiffage Métal’s site in Fos-sur-Mer to form the 45-metre-high floating foundations. These tripod-shaped structures are based on a TLP design developed by SBM Offshore, have a central buoy and two submersible buoys at each end, between which is an innovative anchoring system with tensioned lines. These components were then loaded onto a submersible barge and finally transported to be installed at sea, 17km off the coast.

During the first phase of the project, Sarens was commissioned to lift the major components of three floating foundations for the account of Eiffage Métal at their fabrication yard in Fos-sur-Mer. For the work Sarens used:

• LR1800 (800T Crawler Crane)
• CC2500 (500T Crawler Crane)
• 20 axle-lines of SPMTs

LR1800 was transported from Cadiz in Spain and CC2500 and SPMTs came from Belgium. The cranes lifted and assembled the following components:

• 3 Central Buoys
• 3 Central Columns
• 3 Transition Piece
• 18 Side Buoys
• 9 Side Nodes
• Bracings

Once assembled, Sarens began the second phase of the project in the first week of March 2023 This phase included weighing and load-out of the three floating foundations onto the outgoing barge. Sarens used:

For March 2023 weighing:

• 9 Load cells 500T
• 9 hydraulic jacks 500T
• 3 hydraulic power packs
• Sarens weighing interface

For May 2023 load outs:

• K24ST SPMTs arranged in two trains
• 4 maxi powerpacks K24 operational
• Two spare powerpacks.
• Two 6-axle SPMTs for auxiliary works.
• Four 30-meter MB1500x1000 modular beams

The equipment was transported and assembled on site within a week. Each floating foundation weighed around 2800T and was around 45m heigh and 70m wide. These floating foundations had to be positioned on a semi-submersible barge.

The floating foundations were transported by the two SPMTs configurations over 50 to 150 meters to the quay wall. Crew worked in two shifts to keep up with vessel float-off operation and finally loaded out the floating foundations onto the barge. 

All these operations were supervised by SBM Offshore's team who was responsible for the overall load-out and float-off activities.