The magic of floating
Statoil’s Hywind concept has been tried and tested since 2009, and is now ready for the big leap forward. By choosing a spar buoy as the floating component, we take our knowledge and experience from work in offshore oil and gas and bring it one step further.
It is hard to grasp how large this buoy must be to be able to carry the weight and movement of the windmill itself. Floating in open sea the power from the waves will also have a massive impact on the construction. One day we might be able to take advantage of this power as well.
The spar buoy is in itself a fairly simple concept, but scaled up and carrying the weight of a 154-meter wide wind turbine, takes major effort and ingenuity. The structures have been transported by ship to Stord on the west coast of Norway. There the giant spar-structures has been filled with close to 8 000 tonnes of sea water to make it stay upright. The next step was to fill them with around 5 500 tonnes of solid ballast while pumping out approximately 5 000 tonnes of seawater to maintain draught.
Fixed and floating are complementary
Floating wind turbines bring about new challenges, but challenges we believe can be overcome. At the same time, using floating substructures may have several advantages. We believe the floating offshore wind farms will complement the successful bottom-fixed farms. The two different concepts have much in common, but they also stand apart.
The advantages by producing wind power offshore are many, both by choosing bottom-fixed and floating. The floating wind turbines have currently a higher costs, but they do have some advantages that the bottom-fixed do not have:
- There are limited areas with shallow waters where bottom-fixed wind turbines could be installed.
- There are unlimitied deepwater areas, and wind is often better out at sea.
- The floating foundations for wind turbines can be standardized and mass-produced.