Hywind, the 2.3MW floating offshore wind turbine being developed by Norwegian oil and gas company StatoilHydro, Siemens and Technip has now been installed and moored to the seabed off the coast of Norway. Once cables to the mainland grid have been laid, the wind turbine prototype will undergo a two year pilot which will provide valuable knowledge on how to perfect the technology and hopefully one day enable floating wind turbines to become a financially viable alternative to other energy sources.

Assembly and installation of the huge windmill was a staged process. The substructure was towed horizontally from port to the Åmøyfjord where water was poured in until the structure upended itself. Gravel and stone were then used to lower the structure to the required depth of 100 meters below the surface. The tower, which is 65 meters tall, was added in two sections and finally the generator and the blades were attached, adding another 40 meters to the height. The structure was then towed to its offshore location where three lines secure it to the seabed.

The floating structure consists of a steel jacket filled with ballast and software will control the windmill blades in a way that stabilizes the structure.

“It’s really exciting to see so much good science and so much engineering coming to life. It’s a project with a huge potential," said Alexandra Bech Gjorv, head of New Energy for StatoilHydro.

"We’re looking at building a commercial business with clean energy and offshore wind is going to be a big market segment. With our capabilities from the North Sea we have a lot to offer."

StatoilHydro believes that competencies achieved through becoming a leading offshore Oil and Gas operator have proved vital in helping them develop the Hywind concept.

More than USD$71 million has been invested in the project which began in 2001. Most of the funds have come from StatoilHydro for the construction and further development of the pilot, as well as research and development related to the wind turbine concept. However, Enova SF, a public corporation whose aim is to promote the transition to environmentally friendly energy use and energy production in Norway, has also made a significant contribution.

Hywind facts in brief:

  • Turbine size: 2.3 MW
  • Turbine weight: 138 tons
  • Turbine height: 65m
  • Rotor diameter: 82.4m
  • Draft hull: 100m
  • Displacement: 5300m3
  • Diameter at water line: 6m
  • Diameter submerged body: 8.3m
  • Water depths: 120-700m
  • Mooring: 3 lines
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