Dan Moore and some of his neighbors had complained for years about noise from the nearby Big Blue Wind Farm in southern Minnesota. Their grievances went unresolved.

So, in an unusual move, Minnesota utility regulators intervened in 2017. They found Big Blue had taken up to three years to address noise problems, including a clunking sound that turned out to be a tool stuck in a wind turbine blade.

Regulators found, too, that Big Blue never had its noise protocol approved by the Minnesota Public Utilities Commission — a step required under its state permit issued in 2011. And a noise study that Big Blue eventually did submit to regulators lacked proper data, according to a PUC filing.

As wind farms have multiplied in Minnesota and the Great Plains, they have churned out an increasing amount of clean energy — and revenue for farmers who lease land for turbines. But some wind farm neighbors have become more vocal in their concern about the environmental effects of the big blades on their skyscape. Big Blue and one other Minnesota wind farm are rare in that complaints about them have led to PUC actions.

Moore, a Faribault County farmer, pressed the PUC to shut down Big Blue, alleging the wind farm owned by Granite Falls-based Fagen Inc. had violated its state permit.

"You need to send a message," Moore said at a PUC meeting earlier this month.

The PUC instead opted to allow Big Blue, which is near Blue Earth, to fix the problems — but with a warning.

"If this does not get resolved in relatively short order, [permit suspension] needs to be the next step," PUC Commissioner Dan Lipschultz said at the meeting.

Big Blue, while disputing it was ever out of compliance with its permit, says it's on board.

"We are committed to correcting any complaints or compliance concerns," Fagen CEO Ron Fagen told the PUC. "We will do everything to make this right and meet our regulatory obligations."

Lipschultz and PUC Commissioner Matt Schuerger both said they were at first inclined to suspend Big Blue's license, an unprecedented move in Minnesota for wind farm noise.

"I understand this has been frustrating for you and your neighbors," Schuerger told Moore.

The PUC voted unanimously to require Big Blue to file a new noise modeling protocol and conduct a new, more stringent round of noise testing. A third-party consultant must conduct that work, and its scope must be approved by state agencies.

Big Blue is a relatively small wind farm with 18 turbines that can produce up to 36 megawatts of electricity, enough power for about 20,000 homes. (A megawatt is 1 million watts.) Xcel Energy buys Big Blue's output.

The wind farm went online in December 2012, but not before a legal fight between Fagen and the project's developer, Idaho-based Exergy Development Group. Fagen — a large, family-owned industrial construction company — built Big Blue.

Fagen took ownership of Big Blue just before it opened, after Exergy had defaulted on millions of dollars in credit extended by Fagen. "Mr. Fagen and his family saved this project from going under," said Jim Bertrand, an attorney for Fagen.

Big Blue acknowledged it has faced noise problems since the wind farm began operating, and it has conducted turbine repairs to address those problems, according to PUC records.

Moore has been at the forefront of the noise complaints. He's a corn and soybean farmer, whose parents lease farmland he tills to Big Blue for two turbines. Moore led a group of local farmers who had invested in a company called Windfinity, which started developing Big Blue. Windfinity sold its development rights to Exergy. After Fagen took over Big Blue, it paid the $1.67 million that Exergy owed to Windfinity.

"The wind farm was a dream of mine," Moore told the PUC. He said he thought "that things would be quiet out in the farm field." But the way it turned out, the turbines "are just too loud."

Moore and others had complained of a clicking noise coming from the Big Blue Wind Farm. During maintenance in the spring of 2016, workers removed a tool from a wind turbine blade that had been left during construction, according to a PUC document.

In August 2016, nearby residents were still complaining of a "clickity-clack noise" and a "jet noise" when wind turbines were shut down. By spring 2017, the Minnesota Department of Commerce became aware that complaints about Big Blue weren't being resolved, and it began an inquiry. The department works on behalf of the public in cases before the PUC.

By October 2017, a state Commerce Department report concluded Big Blue had made "substantial progress in addressing the [noise] complaints of Mr. Moore." Adjustments to the turbines appeared to have resolved the "clicking" and "jet engine" sounds.

Still, the commerce department concluded it wasn't satisfied that Big Blue was in compliance with "noise conditions" in its site permit.

The department noted that a mid-2017 noise monitoring study commissioned by Big Blue had found that at certain times, state noise limits were exceeded at the wind farm; wind turbines could have been the cause. Big Blue concluded the noise monitoring was flawed, due to "mechanical breakdowns" and other factors, according to a PUC filing.

Commerce also found that a noise study Big Blue had done wasn't based on a formal protocol that had been approved by commerce or the PUC. Such protocols, which create a baseline for noise monitoring, are usually done around the time a wind farm begins operating.

Big Blue said in a PUC filing that it submitted a protocol back in 2012, but there were "inadvertent breakdowns in the compliance process despite good faith efforts by all parties."

Lipschultz said the noise monitoring process in Big Blue's case was flawed going back to when Exergy was developing the project. "Things didn't go the way they should have in 2011 when this permit was applied for and granted."

However, Big Blue "seems intent on making it good now," Lipschultz said.