Wind power on hold by Julie Buntjer

While the wind hasn't stopped blowing across the prairies of southwest Minnesota and northwest Iowa, the 40-turbine Endeavor Wind Farm near Harris, Iowa, hasn't been able to fully capitalize on the gusts for several months now. Officials with the wind farm, developed by Clipper Wind, discovered late last summer there was a timing issue in the secondary stage of the power train.

"It was ... what we would call a start-up issue - supplier related," said Mary McCann-Gates, director of global communications for Clipper Wind's Carpinteria, Calif., office. "In a nutshell, some of the power trains that we made early on had a timing issue on some of the gears."

To prevent further damage to the gears, McCann said the affected turbines were shut down. The process to replace the drive trains with correctly-timed gears is ongoing, and she doesn't yet know how soon the repairs will be completed.

"As we bring one down, we have a new one that has arrived from the manufacturing facility that we're putting right up there," she said. "All of the turbines at Endeavor don't have the same gear timing issues. Some of them are just fine."

McCann said that as workers replace the power trains, they are also making reinforcements on the blades.

"These blades have to last 20 to 25 years," McCann said. "Since we have the blades down, we feel we have the opportunity to reinforce these blades."

The biggest challenge - and the greatest delay in completing repairs - is the weather, McCann said.

"Working on these blades, the fiberglass material has to set properly; it has to be heated to a certain temperature for it to cure properly," she said. "It's a very precise process. While it's not going to take a tremendously long time, we want to take the time to do it properly."

Both the affected blades and power trains were manufactured at Clipper Wind facilities in Iowa.

McCann said the components, developed for the 2.5 megawatt Liberty C93 wind turbines, began being mass produced in 2007.

"It's like with anything. You see this with cars where you have a recall here or a fix there," McCann said. "This is our first production of a brand new turbine. With a new product, there will be some teething issues."

Despite the "teething issues," McCann said there hasn't been anything wrong with the design of the turbines. The power train timing issue has been corrected by the manufacturer, and the change has been implemented in all of the new blades coming out of the factory, she added.

"For the most part, it's a fabulous project," she said. "These are turbines that have been built in Iowa, installed in Iowa, and they are the largest turbines built in the U.S."

The Endeavor Wind Farm at Harris was purchased by Florida Power & Light in August 2007. Because of the repairs Clipper Wind must make, the acquisition process has not yet been completed.