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Bad gluing blamed for mishaps at wind farm

It all came down to glue. And how it was misapplied by workers.

Spanish wind-energy company Gamesa said “insufficient and irregular distribution of glue” caused large pieces to break off seven turbine blades at the Allegheny Ridge Wind Farm near Lilly, Cambria County. No one was injured during the mishap in mid-March, but pieces of the blades flew more than 500 feet, according to residents.

Gamesa manufactured the turbine blades at its $50 million factory in Ebensburg, Cambria County, which opened last summer with $9.3 million in financial assistance from the pro-wind-energy Rendell administration. Gamesa wants to build a wind farm on Mahantango Mountain in northern Dauphin County using turbine blades from the same plant.

Gamesa announced new quality-control measures on Friday, promising that blades must get a 100 percent passing grade or they will not be shipped. The company brought in experts from around the world to help investigate the mishap.

Gamesa spokesman Michael Peck defended the quality of the 264 workers at the Ebensburg plant, saying they were well-trained in Spain and locally with the help of the United Steelworkers of America.

But wind-industry consultant John Vanden Bosche, principal engineer at Chinook Wind in Everson, Wash., was not so sure.

“This problem most often crops up when there’s a new factory or new personnel in a factory and they don’t really have their techniques down,” he said. “It usually happens on the graveyard shift when there are no managers or [quality-control] inspectors around to make sure the bond is done properly.”

He said gluing the top skin to the turbine’s internal frame, or spar, is tricky because it must be done blind. Problems such as this are “somewhat common” for turbine blades of this size and have been reported by other manufacturers, Vanden Bosche said. One of them, Danish wind-energy company Vestas, built the Meyersdale Wind Farm in Somerset County. An effort to reach an official with Vestas for insight into the issue was unsuccessful Friday.

Gamesa has put in place “mandatory and comprehensive” internal inspections of blades, Peck said. Thermographic – infrared – scanning will be used to determine whether the glue was applied properly.

Blades from the plant also have gone to wind farms in Illinois and Texas. Gamesa did not respond to a question about whether similar problems have been found in blades there.

As the wind turns the blades of a turbine, a shaft in the turbine spins, creating mechanical power. The shaft is connected to a generator, which converts that power into electricity.

The statement from Gamesa continued speculation from the company that weather might have been an aggravating factor in the breakage. Peck said Gamesa will upload new, proprietary software into the turbines that will adapt their operation to weather conditions. He did not elaborate.

From a distance, it is hard to comprehend how large the Gamesa turbine blades are – 140 feet long, about 14 feet wide and weighing about 7 tons, according to the company.

“It’s something the size of a yacht flying through the air,” said Brian Alger, an analyst who covers the wind-energy industry for Strata Capital Management in Beverly Hills, Calif.

Several of the blade pieces landed on property owned by James A. Davis, 69, of Lilly, and leased in part to Gamesa. One piece was thrown more than 500 feet before coming down through the trees, Davis said. That would put it outside the official 300-foot safety zone around each turbine.

Davis said he has one of the smaller pieces in his basement. A larger piece of the exterior skin – he said it was 100 feet long and 14 feet wide – was cut into 4-foot sections by Gamesa employees, who trucked a portable generator and power saw to the site.

By David DeKok
Of The Patriot-News


7 May 2007