News of the world's first full-scale floating windmill being built spread over a year ago. Now, the Hywind has reached its final destination, where it will face rigorous testing. The Hywind concept combines known technologies in a novel way: a 2.3 MW wind turbine is attached to the top of a Spar-buoy, a solution familiar from production platforms and offshore loading buoys. It captures the wind's energy where the wind is strongest – out at sea.
On June 8, 2009, Hywind was moored to the seabed 10 km southwest of Karmøy, Norway. The next step is cable-laying to land, which is scheduled for July. StatoilHydro of Stavanger, Norway is the developer of the Hywind concept, and will be testing the concept over a two year period starting in the autumn of 2009.
StatoilHydro is investing around NOK 400 million in construction, research, and development related to the wind turbine concept. The public corporation Enova SF, whose aim is to promote the transition to environmentally friendly energy use and energy production in Norway, has granted NOK 59 million in support for the project.
Existing offshore turbines are mounted firmly on the seabed. However, foundations become very expensive at water depths of more than 30 to 50 m. Hywind's floating structure consists of a steel jacket filled with ballast. This floating element extends 100 m beneath the surface and is fastened to the seabed by three anchor piles. An advanced control system takes advantage of the turbine’s ability to dampen out part of the wave-induced motions of the floating system. The wind turbine weighs 138 tons and stands 65 m high, and can be placed at ocean depths of 120 to 700 m.
In Kamøy, Hywind is moored at a water depth of about 220 m. The turbine will be connected to the local grid, and is expected to start producing power in mid-July.
Hywind is a collaborative effort. The windmill itself, model SWT-2.3-82, is built by Siemens. Technip builds the floating elements and is in charge of the offshore installation. Nexans will install the cable to shore, and Haugaland Kraft will be responsible for the landfall.