Output from wind turbines on the open sea is approximately 40% higher than on land. To help Dong Energy exploit wind power more efficiently, Siemens will be installing 300 gearless, new-generation wind turbines off Britain’s coast and providing service as well.
The 6 megawatts (MW) wind turbines are expected to supply about 1.8 million households with environmentally friendly electricity by the year 2017 at the latest. With a total capacity of 1,800 megawatts, these turbines will set new standards in efficiency and cost-effectiveness.
All this is possible thanks to the type B75 rotor blades. With a length of 75 metres, they are the world’s largest, and they make it possible to build rotors with a diameter of 154 metres. In a single rotation, they sweep across an area of 18,000 square metres – that’s equivalent to 2.5 soccer fields!
But that’s not their only amazing feature: weighing in at just 25 tons, the B75 rotor blade is a lightweight. Although it weighs as much as four bull elephants, it is 10-20% lighter than comparable rotor blades – and that helps to reduce construction costs for foundations embedded in the seafloor. Its light weight results from Siemens’ patented “IntegralBlade” process. There are no seams or bonding points. This blade is the largest fibreglass component ever manufactured from a single mould, and that adds up to maximum yield, maximum strength, and minimum weight.
The B75 blades will be installed on the second prototype of the 6 MW Siemens offshore wind turbine being built in the Danish Østerild this summer. Transporting the fibreglass giant will be a logistical feat.