Vestas develops "stealth" rotors on wind turbines

Wind power equipment maker Vestas today said that it had successfully tested a full-scale ''stealth'' rotor on a turbine, that does not interfere with radars used at airports.

The new stealth rotors would help in paving the way for wind power plants to be located near many military, airport and other radar systems without interfering in their operations, it said.

The Danish wind turbines manufacturer said it had successfully tested its stealth turbine at a UK customer site along with its technology partner QinetiQ, as part of an ongoing research collaboration that began in 2006. 

According to Vesta preliminary test results, announced today at the International Wind and Radar Forum in Ottawa, Canada, showed that a Vestas V90 turbine with stealth rotor achieved a targeted reduction in radar cross-section of approximately 99 per cent, or 20 decibels, compared with standard turbines.
''Our testing has demonstrated that we have successfully adapted military stealth technology to make Vestas wind turbines viable for placement in many locations that have been restricted by radar concerns,'' said Vestas Technology R&D president Finn StrÝm Madsen.
''This is a critical step toward the commercialisation of stealth turbines and holds potential to open a significant number of wind power locations for Vestas customers.''

With an estimated 20 gigawatts of wind power capacity currently blocked worldwide by concerns about radar interference, Vestas' stealth turbine research has validated a potentially important addition to the operational, technical and political mitigation tools available today.
The stealth turbine solution uses a radar absorbing materials that are integrated into the current manufacturing processes for turbine components and can be designed to operate at aviation and maritime frequencies.  These modifications do not affect the performance or appearance of the turbines, which meet current visual standards.

The full-scale test announced today follows more than five years of research collaboration with UK-based QinetiQ to develop and improve the application of military stealth technology to wind turbines.  Early laboratory and wind tunnel testing progressed to initial site testing of a single, 44-meter blade in late 2009.  Additional design optimization led to process cost reductions and quality improvements that were verified by the full-scale testing of a three-blade stealth turbine in 2011.
Wind power from Vestas' more than 43,433 wind turbines currently reduces carbon emissions by approximately 50 million tons of CO2 every year, while at the same time building energy security and independence.