THE INSTALLATION PROCEDURE IS DIVIDED INTO THE FOLLOWING STAGES:
1. Onshore construction process
The foundation is manufactured in a low depth dry-dock, combining precast concrete and in-situ manufacturing.
The tower levels are divided into panels that are manufactured at nearby precast facilities, and are pre-assembled in an adjacent area to the dry-dock.
2. Buoyant launching
The foundation is then floated out of the dry-dock.
3. Base completion and assembly of folded telescopic tower
The foundation base is completed and the tower levels are assembled onto the foundation.
The assembly can be at this point set for temporary storage while the nacelle and blades arrive, if such is the case.
4. Installation of nacelle and blades
The system allows for the low-rise installation of the turbine and blades, as well as for the pre-commissioning of the turbine.
5. Tower transportation to final location
The use of cells in the foundation base and the stable design of the assembly allow for a self-buoyant transport of the complete wind turbine with conventional tugboats.
6. Seabed preparation and positioning
An auxiliary floating system, using buoyant elements, is installed temporarily around the tower to provide the required stability during the water ballasting of the assembly once it has arrived to the final position.
Three small tugboats are also used for the positioning operation, and a seabed preparation can take place if required.
7. Partial lift of top tower level
In order to ensure water clearance to the blades, the top level is lifted using the hydraulic jacks located in the lower joint of the tower.
The foundation cells are filled with water, allowing for the controlled ballasting of the base, down to the seabed. Afterwards, the solid ballasting can take place, displacing the inside water with solid ballast.
9. Final tower lift
Telescopic tower final lift with conventional hydraulic heavy lift jacks, executing all the lifts and horizontal joints from the same single working platform at sea level.
The decommissioning of the turbine can benefit from the reversibility of the tower installation process, by refloating the foundation and lowering the tower levels using the hydraulic jacks.
The assembly can be then transported to land before it is fully de-assembled.