The WindFloat can accommodate any offshore wind turbines, from the traditional medium and high-speed gearbox driven turbines to today’s most advanced direct drive, downwind, or vertical axis options and inclusive of tomorrow’s future designs. Ultimately, the turbine chosen for a WindFloat project is defined by the project developer and the other skateholders. The WindFloat does not restrict turbine selection in any way and can enable the possibility of even larger turbines by reducing the logistical and cost challenges typically associated with larger units onshore.
Boat Landing and Deck Hardware
In most locations, operations and maintenance access to the WindFloat is accomplished by crew transfer vessel. The WindFloat can accommodate a variety of custom boat landing configurations to support various vessels requirements. Catenary moored floating structures are not subject to tidal variation, which can simplify boat landing design and cost. With three columns, the location of the boat landing can be chosen to maximize sheltering opportunities. Typical WindFloat deck hardware includes a winch, a temporary back up generator, navigational aids (as required by local consent authorities) and a davit for maintenance activities.
Hull-trim System (Active Ballast)
The WindFloat’s patented hull-trim system (also known as active ballast) distributes water ballast between the three columns of the WindFloat to compensate for variable turbine thrust due to low frequency changes in wind velocity and direction. The system is closed-loop (no water moves in or out of the system), fail-safe, and comprises only a small fraction of the total WindFloat ballast water. The result is a floating offshore wind turbine foundation with a horizontal mean position in pitch and roll. This is a key design feature of the WindFloat.
Static Water Ballast (Static Stability)
Similar to offshore Oil & Gas platforms, the WindFloat uses sea water ballast to submerge approximately 2/3 of the structure below the mean water line. This inexpensive and readily available form of ballast material compensates for the excess buoyancy of the hull (useful during load-out of the structure at quay side in a harbor) and lowers the overall center of gravity of the WindFloat.
The WindFloat’s conventional mooring system only includes components that are relatively inexpensive, readily available globally, and simple to install. The mooring configuration is similar to those on Oil and Gas platforms and permanently moored maritime structures. Drag embedment anchors permit installation in various soil conditions including mud, clay, sand and layered soils. Their installation is less weather-dependent than other alternatives, and installation does not require full geotechnical surveys of the sea bed prior to design. Further, the incremental cost increase, due to water depth, associated with a WindFloat mooring is minimal. This permits greater flexibility in site location and turbine placement to customers.
Water Entrapment Plates (Dynamic Stability)
The patented water entrapment plates,outfitted at the based of the WindFloat columns, contribute significantly to the motion performance of the WindFloat. The plates “entrain” water resulting in a large added-mass component and the sharp edges of the plates increase the viscous damping due to vortex shedding. This is a key design feature of the WindFloat.