Blade repairs are tricky, Moya said, because the weight and thickness of the repair materials have to be perfectly matched to the blade. Otherwise, a blade ends up lighter or heavier than the others on the windmill, causing the entire apparatus to wobble like an unbalanced tire and ultimately fall apart. "We send images of the damage to our engineers in Houston. They send detailed blueprints back about what needs to be replaced," Moya said.

Lightning knocked out two wind turbines and sent a massive tower blade crashing to the ground at the Judith Gap Wind Farm last month, the company said Wednesday. Repairs began earlier this month and will continue into September, said Susan Dennison, an Invenergy spokeswoman.