Industry officials are investigating an accident that occurred this week in which a rotor and blades fell from a tower at the Rugby Wind Power Project near Rugby, N.D.
No one was injured in the incident, which is believed to have occurred sometime during daylight hours Monday, according to Jan Johnson, communications director for Iberdrola Renewables, which operates the 149.1 megawatt wind farm.
“Nobody was in the vicinity when it happened,” she said.
The rotor assembly and three blades are attached to a hub. So, when the rotor became detached, the blades fell, too, Johnson said.
“It’s kind of a unique situation,” she said, “It hasn’t happened before; certainly not in our fleet, and not that I’m aware of anywhere else.”
While Iberdrola has maintenance crews on the farm during normal business hours, the facility is not staffed around the clock. The company monitors wind farms throughout the country from a central technical facility at the company’s headquarters in Portland, Ore.
The company reported the incident to the North Dakota Public Service Commission, which regulates the state’s wind energy industry.
In the meantime, the incident is being investigated by officials from Iberdrola and from Suzlon Wind Energy Corp., wind turbine manufacturer.
“These investigations tend to be very thorough,” Johnson said.
The Rugby facility, which was dedicated in October, includes 71 wind turbines. A portion of the energy produced there is sold to Missouri River Energy Services, based in Sioux Falls, S.D.
The structures at Rugby stand 407 feet tall, from the bottom of the turbine to the top of the highest blade at 12 o’clock.
The S88-2.1 megawatt turbine is designed for medium wind speeds and to withstand extreme conditions, according to Suzlon’s website. The blades were manufactured at Suzlon’s manufacturing facility in Pipestone, Minn.