— Structural issues that may be cost-prohibitive to repair may mean the permanent shutting down of
wind turbine No. 3, and wind turbine No. 4 continues to have electrical issues that are being worked out.
Although wind turbine No. 3 generated more power in June than turbine No. 4, it is now shut down until the structural issues can be addressed — if they can be addressed.
Both turbines are located near Willmar Senior High School: No. 3 is the north tower, and No. 4 is the south tower closest to the school.
Electrical Engineer Jeron Smith informed the Utilities Commission on July 8 that a blade pitch issue initially shut down No. 3, but more significant issues were discovered by Willmar Municipal Utilities wind technicians when they went up into the turbine to investigate.
One-inch steel brackets that connect the Fiberglass nacelle housing on the top of the tower to the frame are all cracked and bent, according to Smith. The nacelle houses all of the generating components in a wind turbine, including the generator, gear box, drive train and brake assembly.
“It’s in really bad shape,” Smith said. “It’s beyond our wind techs’ ability to repair.”
Willmar Municipal Utilities is consulting with a company to evaluate the situation and discuss different options on how to address the issue, according to Smith.
“We’ll probably come forward with that once we’ve got a plan in place, but it’s going to stay at a standstill until then,” Smith said.
Utilities Commissioner Dave Baumgart asked if it is something that can be repaired.
“To show behind the curtain, it’s likely we’ll need a crane to bring it down on the ground to repair it and it’s going to be cost-prohibitive,” Smith said. “The question is, is it something where we can rebuild the bracket, bring it up there and somehow support the cell housing in some temporary fashion to replace those brackets?”
He noted that Municipal Utilities staff would not be capable of such a challenge.
General Manager John Harren added that wind turbine No. 3 is also having other issues that need to be fixed at this time, but did not elaborate on it.
Wind turbine No. 4 continues to have electrical issues that cause it to stop functioning and the wind technicians continue to work through those, according to Smith.
“It was about mid-June that we got the synchronization issue worked out, but we’re still getting a control plus fault issue that we’re trying to work through,” Smith said. “Unfortunately, it’s sporadic and it only happens after hours.”
In the month of June, wind turbine No. 3 had an availability of 86% and produced 176,007 kilowatt-hours of power; wind turbine No. 4 had an availability of 27.9% and produced 45,376 kilowatt-hours.
