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DTE explains broken turbine blade

HURON COUNTY – A spokesperson for DTE Energy explained how a wind turbine blade in Sigel Township broke earlier this year in a presentation Wednesday night to the Huron County Planning Commission.

The blade broke at 1 a.m. March 11 on Parisville Road near Learman Road because of a manufacturing defect by General Electric, said DTE spokesman Dennis Buda.

A new blade was ordered, and the wind turbine returned to service on May 31.

“The cause for the blade breaking was a carbon failure at the 19-meter mark that was not formed properly,” Buda said. “Failure in the heating oven at the plant caused the blade to break later on.”

After the presentation, commission members asked Buda if high winds could have contributed to the blade breaking. He repeated that the failure was because of the carbon irregularity on the blade, not high winds. He later spoke of how properly made wind turbines can handle wind speeds up to 125 mph.

Buda said that despite the strength of the new wind turbines, DTE computer programs will automatically adjust the turbines to a slower speed if winds surpass 55 mph.

“Wind farm energy has come a long way in recent years,” Buda said. “These blades travel at 200 mph around in a circle.”

Buda said that the GE report to DTE Energy stated the oven that heated the blade for Sigel Wind Turbine SI-35 was accidently shut down in production for two hours during the building process. The factory where the blade was produced is in Brazil and GE will add nine additional inspectors to the plant. He said the issue was noted by the oven’s engineer, put not passed “up the ladder” by General Electric workers to the production inspectors before the blade was shipped.

“We’ve combed each blade on all 139 of the other wind turbines in operation and haven’t found another problem,” said the spokesman. “It was a one-time issue.”

The spokesman said that DTE and GE went over the turbine blade with an electron microscope when the malfunction occurred to see where the break occurred.

“We still have complete confidence in GE,” Buda said.