Mechanical motion technology is a key element in the evolutionary path and
long-term growth for wind energy solutions. With the design of wind turbines
clearly defined, recent developments are focusing on the reliable performance
of gearboxes and hydraulic/electric solutions for pitch and yaw control.
"The most significant developments center
on increasing the reliability, efficiency and cost of the wind turbines," says Till
Deubel, manager for Market Segment Energy for Bosch-Rexroth. "Increasing
reliability and efficiency is directly related to techniques for better pitch
control, decreasing the stresses on bearings and reducing spikes and other forces
on the mast."
Deubel says pitch
control is an important motion system used to change the angle of the wind
turbine blades and adjust turbine operation for different wind speeds. Pitch
motion is controlled using both hydraulic and electric systems and is a key
area for innovation.
"Up until now, pitch
control has used blades that are pitched at the same angle but now we're
looking at individual pitch control," he says. "Each blade can have an
individual pitch angle and be adjusted independently based on whether the blade
is in an up or down position. This allows the system to compensate for the fact
that the wind is stronger in the up position than it is in the down position. By
slightly changing the pitch angle, the system can reduce the stress on the
bearings of the wind turbine."
According to Dr.
Christoph Seifert of Bosch Rexroth AG, offshore wind parks are also an
important technology focus, especially in Europe.
He says industry has developed a new generation of wind energy plants
specifically for use on the high seas which is now ready for series
production. Bosch Rexroth has expanded its capacity for producing the large
wind-turbine gearboxes generally used in offshore installations by opening a
new facility in Nuremberg, Germany. The plant will manufacture
around 300 large gearboxes in 2009 for the latest generation of multi-megawatt
An important development for these offshore
locations is software which monitors the condition of the rotor blades and
warns the control unit in the case of icing. Condition monitoring systems issue
warnings before wear or damage can occur, and allows operators to better plan
maintenance measures and increase the availability of the wind energy plants.
"Having enjoyed annual growth rates of
up to 30 percent in the recent boom years, wind energy is making somewhat
slower progress in 2009," says Seifert. But he says signs point to a
return of double-digit growth rates within the next two years.