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Siemens Blade Technology

• To date, Siemens has introduced three major innovations in blade technology – the IntegralBlade, the Quantum Blade and the next-generation Quantum Blade, namely the Aeroelastic Blade.

• Over the last 30 years, Siemens blades have grown 15-fold and harvest ever more energy: The first commercial Siemens wind turbines had a capacity of 30 kW and 5 meter long rotor blades. In comparison, the new Siemens 6 MW wind turbine features a 75 meter long blade resulting in a 154-rotor diameter.

• With a length of 75 meters, the B75 Quantum Blade is the world’s largest rotor blade today. The first three prototypes of the B75 were produced in 2012 and will be installed in the second half of the year in Denmark.

• Blade tests are being performed at Siemens’ R&D facilities in Aalborg, Denmark. Siemens is changing industrial standards for component testing by running every component such as blades through a simulated 25 years highly accelerated lifetime testing (HALT). For blades, Siemens runs statics and fatigue tests.

IntegralBlades

• In 2000, Siemens made its first major blade technology advancement with the development of the IntegralBlade® process.

• Since then, Siemens is the only wind turbine manufacturer which uses blades cast in one piece in a closed process.

• The Siemens process eliminates glue joints, providing blades with optimum quality, strength and reliability. The IntegralBlade technology contributes significantly to reliability of Siemens turbines.

Fact Sheet: Rotor Blades Lowering the cost of energy by smart technology

Status: June 2012

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First generation Quantum Blades

• In 2011, Siemens introduced the ground-breaking Quantum Blade technology. Quantum blades are lighter than previous models while retaining the superior strength of earlier generations.

• As of 2011, all new Siemens rotor blades are designed as Quantum Blades. Like their predecessors they continue to get produced using the IntegralBlades® process.

• The original Quantum Blade concept was created in 2008. As usual, Siemens tested the concept thoroughly before introducing it to the market. The first commercial version of the Quantum Blade is the B55.

• The B55 blade is 55 meters long and features redesigned tip and root sections. The root section uses Siemens “flatback“ profiles to minimize root leakage and provide greater lift. The blade tip has also been redesigned to minimize loads and reduce noise levels. The B55 was introduced together with the SWT-2.3-113, Siemens` second direct-drive wind turbine which is designed for low to moderate wind conditions.

• The new Siemens 6 MW offshore wind turbine features the world’s largest rotor blade: the new B75 Quantum Blade. This 75 meter long blade features enormous strength at low weight. Thanks to its unique airfoils with “flatback“ profiles the B75 offers superior performance at a wide range of wind speeds.

• If the B75 blade had been produced according to traditional methods used elsewhere it would have been 50 percent heavier. Heavier blades lead to higher loads and require stronger supporting structures in the nacelle, tower and foundation. Thus, the unique combination of smart blade profile and low weight significantly contributes to reduce the cost of energy.

Second-generation Quantum Blades (Aerolastically tailored blades)

• The second generation quantum blade uses the so called Aeroelastically Tailored Blade technology (ATB). Thanks to the aeroelastic features using a coupling between blade bending and blade twisting the structural load on the blade is significantly reduced.

• This bend-twist coupling of the ATB technology represents a major advance compared with classical rigid blades. Thanks to their innovative aeroelastic properties, a rotor with ATB technology can be made with a larger diameter without increasing the loads on the nacelle, tower and foundation. As a result, the annual energy output can be increased without any cost penalty on the structure.

• Siemens has introduced a new 53 meters long blade for the 2.3MW workhorse platform of the product portfolio. The new B53 blade is four meters longer than its predecessor, the B49, yielding an eight percent increase in annual energy output. Applying Quantum Blade technology, the new blade is even several hundred kilograms lighter than its smaller predecessor.

• Serial production of the Aerolastically Tailored Blades has started in 2012 in all three Siemens blade production facilities (Fort Madison, US; Aalborg, Denmark; Shanghai, China).

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Aerodynamic accessories

• Aerodynamic accessories,known as DinoTails®, DinoShells® and Vortex Generators are among the add-ons that make the efficience of the Siemens blades even better.

• Aerodynamic add-ons have been in use at Siemens Wind Power for more than a decade.

• Applying aerodynamic add-ons can both maximize the aerodynamic performance and robustness with regards to roughness sensitivity. Roughness sensitivity is explained as the decrease in rotor efficiency during periods with blade soiling vs. periods with perfectly clean blade surfaces. Blade soiling is typically encountered as layers of bugs, dirt or dust particles which accumulate on the blades during operation.

• Moreover, the aeroelastic add-ons can also reduce noise emissions.

DinoTails®

• DinoTails® are serrated flaps, like the tail fin on a stegosaurus.

• By decreasing turbulence on trailing edge of a blade , DinoTails® make the blade quieter. DinoTails® can also enhance lifting performance, while keeping local acoustic emissions to a minimum.

• The Dino Tails® are placed close to the blade tip. This part of the blade is the noisiest due to the blade tip’s high velocity. Also, it is this region of the blade that accounts for most of the energy production.

DinoShells®

• DinoShells® also belong to our family of lift-enhancing devices. The DinoShell® is a combination of a Gurney flap known from racecars and an ordinary flap with an overlaid seashell structure.

• DinoShells® as applied on Siemens turbines are fixed control surfaces attached at or near the trailing edge of the blade surfaces. They give the blade a “spoiler effect” thus increasing lift. On Siemens turbines, DinoShells® are used to increase the lifting capacity especially on the thick part of the blade closest to the hub.

Vortex Generators

• Vortex Generators (VG’s) are aerodynamic “turbulators”. Turbulators are designed to improve the flow of air over the wind turbine blades. They do so by enhancing mixing in the so-called boundary layer: the region of flow very close to the blade’s surface.

• Siemens uses vortex generators to enhance aerodynamic performance.

• On wind turbine blades, vortex generators are often used on the part of the blade closest to the hub. Here the shape of the blade is determined mainly from structural reasons, which leads to a non-optimum aerodynamic shape. Furthermore transport restrictions cause limitations to the maximum width of the blade. Vortex generators can improve the aerodynamic performance of this part of the blade.