A PLUG AND PLAY PRODUCT
The main advantage of the semi-submersible floating wind turbine is its ability to deliver an operational fully assembled product. This deployment is neither possible for onshore wind turbines nor for bottom fixed wind turbines. Onshore, subassemblies of the turbine need to be transported by truck on site and it often necessitates special roads building. Offshore, assembly of the turbine mast and its blades is made at the production site and requires costly dynamic positioning vessels.
Eolink wind turbines are easy to build onshore and commissioning on site is facilitated thanks to a plug and play connection. The 15 MW floating wind turbine is compatible with low depth harbors thanks to its 5 m draft.
A FAST TRANSIT SPEED
Eolink’s hull shape floater is towed on site at the speed of 7 knots (13 km/h) whereas competitors don’t reach more than 2 knots. Fast towing is possible thanks to the catamaran structure having a low drag and a high stability before ballasting. The plug and play connexion has been thought to hasten wind farm deployment, by decoupling anchors and main grid installation from turbine commissioning. The single point mooring buoy is the heart of this fast deployment.
Single Point Mooring (SPM)
DECOUPLING GRID & ANCHORING INSTALLATION FROM WIND TURBINE CONNECTION
The single point mooring system ensures mechanical and electrical connexion between the submarine network and the moving wind turbine. Installation process starts from pile driving on the seabed, this operation is mutualized for farm application as an anchor can be used by up to three wind turbines. Once anchors are set, the mooring lines and SPM are installed using a light vessel that is able to carry the SPM. The same is done for the grid connection using inter array cables between wind turbines. Both mutualisations mitigate installation costs.
The last operation, which consists of the wind turbine connection, is done independently. The turbine is towed to site and another light vessel connects the hawsers and the dynamic cable to the turbine.
This new process provides higher flexibility for marine operations usually constrained by weather conditions and vessels availability. Unlike other competitors, an Eolink turbine can easily be disconnected from the grid while keeping the whole array functional
The single point mooring dissociates inter array cable (red) and anchor (black) installation from turbine commissioning
In order to maximize production, wind turbines have to be operational at any time to exploit wind energy. Time availability will be higher than 95%.
Even if floating wind turbine facilitates commissioning, their maintenance is more expensive because of the distance to port. In addition, some operations are hazardous on the sea and cannot be done during bad weather conditions. To prevent damage and production interruption, Eolink uses condition monitoring on all the structure and anchors via connected sensors.
In addition, number of breakdown and maintenance operations directly depends on the number of components. By integrating 15 MW wind turbines, Eolink divides by three maintenance operations compared to the average offshore wind turbine.
Eolink presents 2 innovative solutions to mitigate unavailability costs.
To ensure the safety and ease of maintenance operations, they are carried out entirely from inside the hull. Accessible via a protected landing stage, the interior of the wind turbine is isolated from the humid and saline marine environment.
Secondly, heavy maintenance is carried out in harbor. The float is disconnected from the buoy, quickly towed by a light vessel back to harbor and the turbine is replaced by another one. Eolink is the only floating structure which offers easy towing back to harbor thanks to the single point mooring technology and a fast towing speed which reduces travel time. In addition, the moderate width of the float allows entry into a standard dry dock. This disconnection system keeps the inter-wind turbine network operational.
By taking advantage of these solutions, Eolink decreases maintenance costs.