Record breaking wind turbine rotor blade

Measuring 75m in length, the blades are almost as big as the wingspan of an Airbus A380. Beginning this fall, the B75 rotor blades will be installed into a prototype 6MW offshore wind power system in Denmark’s Østerild test station.

As it moves, each rotor covers 18,600 m2, which is the size of two and a half soccer fields. The tips of the blades move at up to 80m per second, or 290 km per hour. The huge rotor was made possible by special technologies that enable Siemens to make extremely strong yet lightweight structures.

To produce the B75 rotor blade, Siemens uses the patented IntegralBlade process, in which the entire blade is poured as a single piece made of glass fibre reinforced epoxy resin and balsa wood. As a result, the blade has neither seams nor bonded joints and is extremely robust. The gigantic rotor, which measures 154m, has to withstand huge air masses, as it is hit by the energy of 200 tonnes of air per second when the wind blows at a speed of 10m per second.

Thanks to another patented process, QuantumBlade, the rotor blade weighs 20% less than conventionally produced blades. As a result, the nacelles, towers, and foundations can be made lighter as well, which reduces the facility’s cost. The weight reduction is achieved by using specially designed blade profiles that are also shaped in a way that delivers maximum rotor performance at a range of different wind speeds.

The first two 6MW turbines from Siemens (equipped with standard 60m rotor blades) are now being installed and tested at the Gunfleet Sands wind farm off England’s south coast. Over the next several years, the Danish energy supplier Dong plans to install 300 gearless Siemens wind turbines off the British coast. These turbines will be equipped with the new rotor blades.