Wind turbines can reflect radar waves, appearing on radar screens as ‘clutter’ in an unpredictable and confusing way. But Vestas hopes to open up new potential wind farm sites by coating blades with a similar material to that used to make stealth bombers invisible to radar.
With an estimated 20 GW 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.
Vestas showed that a V90 turbine of the company with stealth rotor achieved a targeted reduction in radar cross-section of approximately 99 percent, or 20 decibels, compared with standard turbines.
The stealth turbine test, which was conducted at a UK customer site with technology partner QinetiQ, is part of an ongoing research collaboration that began in 2006.
"Ourtesting 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 Strøm Madsen.
"This is a critical step toward the commercialization of stealth turbines and holds potential to open a significant number of wind power locations for Vestas customers."
The stealth turbine uses a portfolio of radar absorbing materials integrated into the current manufacturing process. Vestas with partner QinetiQ has been testing a full scale "stealth" rotor on a turbine as part of on-going research that began in 2006.
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.