Each yaw ring replacement will cost about $50,000 dollars, says Vestas service manager Hans Laurids Pedersen. The retrofit will be carried out on one turbine in Norway, one in Spain, three in Sweden, eight in the United States and eight in Germany. He adds that the adjustments made on other 1.65 MW turbines appear to have halted the problems. No new cases of yaw ring damaged have been detected in the past three months.
The problem was caused because the three blades were not pitching identically, says technical director Mogens Filtenborg.