Cause of wind turbine damage unknown

"It's a good machine," said Jefferies analyst Michael McNamara of the Enercon product.

"All turbine manufacturers suffer breaks. It's what causes the break that's the issue," he said.

Indian turbine maker Suzlon Energy had to recall blades in the United States when some cracked and broke, McNamara said.

(Reporting by Daniel Fineren and Gerard Wynn, editing by Anthony Barker)