More than 400 “defective” motors are being replaced on 134 wind turbines in Tuscola County due to a design flaw that has neighbors complaining of loud clunking noises.
A representative of NextEra Energy Resources L.L.C. said Thursday that the replacements on wind turbines within two of Tuscola County’s “wind farms” are well underway, not only to address the loud clunking but also because the motors are likely to fail.
He disclosed the information when providing the Gilford Township Board of Trustees an update on complaints received in 2016. The information is provided annually per township ordinance.
“The major complaints were the clunky noise and we’re in the process of resolving those,” said Steve Gauger, wind site manager, NextEra Energy Resources.
Gauger said he is in charge of operations and maintenance for all wind turbines in Gilford and Fairgrove townships that are part of either Tuscola Bay Wind Energy Center or Tuscola Bay II Wind Energy Center.
Power generated at Tuscola Bay is sold to DTE as part of a 20-year, $485 million contract announced in 2011. Tuscola Bay II also sells power to DTE. The company also wants to build Tuscola III Wind Energy Center in Fairgrove, Almer and Ellington townships and has filed special land use applications for the project that calls for 52 wind turbines and a price tag of about $200 million.
Gauger told the board that, in Gilford Township, NextEra Energy Resources “really only had four or five complaints” in 2016.
However, a copy of the complaint log was provided to The Advertiser by township supervisor Jim Stockmeyer and shows there were actually 30 separate complaints logged.
Stockmeyer was among those who filed a complaint, but the majority were filed by one family between March and October.
Gauger said complaints mostly were due to loud “clunky” noises.
He told the board that the problem was identified as the motors contained within each wind turbine (each wind turbine contains three motors, one per blade).
Gauger said it’s been determined that the “old style” keyway pitch motor is “defective” and not able to handle the load that is being placed on them by longer blades. He said the motor is essentially trying to adjust itself so that there is less drag.
“What happens is on the upswing or the downswing, it’s actually got some slack in there and that’s that clunking noise that people are hearing,” Gauger said.
He said the motors originally installed in all 134 wind turbines as part of Tuscola Bay and Tuscola II are being replaced, “starting with any complaints that we do get, we start with those ones first.” They will use a differently designed motor identified as a “spline drive” pitch motor. Gauger said the new motors feature “a lot better design.”
Gauger said out of 402 motors in the project, 177 have been replaced.
Stockmeyer said he “could tell right away” that the wind turbine he complained about had been fixed.
Gauger said the company has contracted a third-party to help with the replacements, which he said are covered under warranty from GE, the manufacturer. One shipment a week of replacement motors are being sent to the area to address the problem, he said. The company is averaging fixing “three or four” turbines a week, he said.
Other issues related to wind turbines in Gilford Township were identified Thursday.
Gilford Township Trustee Kent Houghtailing pointed out that “fins” attached to wind turbine blades post construction were falling off.
“I don’t know what you call them, but you glued some fin work on the blades here a year or two ago and we’re picking up a lot of them,” Houghtailing said.
Gauger identified the “fin work” as vortex generators. He said all of them have been removed that are along M-138 and “close to major highways.”
“As soon as the weather breaks, GE is supposed to come out, too, and they’re going to remove them all,” Gauger said.
At least two of the vortex generators were “eaten up” by farming combines, he said.
“It was one of those things where we felt like we weren’t getting the performance out of the turbines that we were told by GE. This was their fix. It didn’t make a difference. They weren’t installed correctly,” Gauger said to Houghtailing. “You’re not the only one. We have a lot of them out there so we are going to be taking them off this year.”
Gauger said all landowners were allegedly notified via “phone call or letter” that if they are working within a certain distance of a turbine, “they call me, I shut the turbine down so they can work safely by it.”
Also in 2016, Gauger told the board that the company filed “a couple” of wildlife reports with the Michigan Department of Natural Resources. The wildlife issues were related to animals who died near turbines or were disposed near turbines. The animals were several deer and a cat.
“We made the reports to the DNR just because birds in the area…they might use that as a meal and then they’re getting close to the turbines and they may get hit by the turbine, as well,” Gauger said.
“We try to cover all the bases because somebody out there, or outside perspective, doesn’t like us or something like that might look at it weird, so…” Gauger said.
With regard to the landowner who filed more than 25 reports between March and October, Gauger said the company considers the issued resolved.
Gauger said the company “did some noise studies with some handheld equipment we had at the site and we were within compliance of the Gilford Township ordinance, which I believe is 55 decibels at 1,325 feet.”
“They acknowledge the clunking is gone but they’ve had issues with other sounds that we can’t pinpoint,” Gauger said, adding that whenever they have called him, he has followed up to try and determine the source of any issues.
“At this point, we feel we’re within the ordinance of Gilford Township,” Gauger said. “You know, they’ve done some Internet research, they don’t have any evidence other than just their hearsay and…I’m not getting any other feedback from anyone else in the area so we feel it’s resolved at this point.
“If it does come up again, we’ll address it or try to do what we can,” he said.