The first 14 XXL monopiles manufactured in Spain by the JV Navantia Seanergies-Windar Renovables were transported with flexible site planning and heavy lifting equipment by transport engineering specialist Mammoet.
Mammoet said that as offshore wind turbines continue to grow, bespoke engineering solutions are needed to accommodate the handling of their foundations. The specialised equipment used to lift and transport their heaviest parts must be upgraded or, in some cases, created.
When Navantia Seanergies-Windar Renovables became one of the first companies in Spain to fabricate XXL monopiles, Mammoet assisted with the marshalling of the components at Navantia’s Fene production facility in Ferrol. Mammoet planned a route to transport the massive monopiles to different workstations on the dock, before loading them onto delivery vessels, bound for Scotland, for the Moray West offshore wind farm that is being developed by Ocean Winds.
The 14 XXL monopiles measured 90 m in length, and 10 m in diameter and weighed up to 2,000 tonnes each. All of them were carried out to a storage area once they were manufactured at Fene´s workshops.
For installation vessels to lift safely, it is crucial to know the final weight and centre of gravity (COG) of each monopile. Each was weighed before being moved to a temporary storage area, near the quayside, where it would wait to be loaded onto delivery vessels in batches of two and three.
Sales manager Javier de Pablo Arenzana said: “Mammoet was able to be flexible and adapt not only to the schedule but also the surroundings. We have worked in this facility in the past. We helped the client to plan and study the route, in case they had to perform any civil work in the area. From this, we determined that steel plates were needed at certain points to ensure the ground was level and flat. We also coordinated the route between the different stations.”
A total of 60 lines of SPMTs were used to move the monopile foundations. The trailers were equipped with specialist equipment designed for the movement of XXL monopiles in particular. The SPMT attachment, a cradle system, comprises foldable saddles that limit the local deflections of the monopile by supporting it as high as possible when in a horizontal position.
This SPMT transport configuration was then used to move the monopile foundations to each station and drive them onto the vessels using a ro-ro ramp, avoiding the need for cranes. Mammoet also performed the final weighing operation, which was done using hydraulic jacks and load cells.
The painting station proved to be the biggest challenge on the route, with operators needing to change the orientation of the XXL monopiles, which involved a full 180-degree rotation before they could enter the area.
In some situations, it was also necessary for painted monopile foundations to be driven directly to the storage area and bypass the weighing station, if it was already in use. This was done to prevent delays in the manufacturing process.
