The Sounds of Silence
A New Hurdle for Wind Farms?
Last spring, the Madison-based environmental group Clean Wisconsin set out to dispose of an issue raised wherever new wind-powered electric generation is planned—namely, noise emitted during turbine operation. By January, it was clear that in trying to remove the issue, Clean Wisconsin hit a tripwire and the result could be a whole new layer of regulatory review for wind development.
Ironically, what thwarted Public Service Commission (PSC) approval of Emerging Energies of Wisconsin’s Highland Wind project in St. Croix County was the relatively straightforward problem of audible turbine noise that can be alleviated by design, equipment, or operational changes. The peculiarities of “infrasound and low-frequency noise” (ILFN) didn’t figure in the PSC’s recent 2–1 denial of the application. But as the lump under the rug through Highland’s 20-month regulatory review, ILFN might have serious implications for future projects.
What You Can’t Hear Won’t Hurt You?
Both audible turbine noise and ILFN are frequently alleged to cause adverse health effects, but published research supports both sides of the argument. Current siting standards regulate audible noise because whether or not it harms anyone, it’s a recognizable irritant.
“Recognizable” is less descriptive of ILFN, which is largely below the threshold of detection by human ears. But people who say they recognize its effects aren’t scarce. Prime examples are the three Brown County families who’ve abandoned their homes in the Town of Glenmore since the Shirley Wind Farm began operations in December 2010. Nausea, headaches, and vertigo are on the long list of symptoms claimed by at least 50 Shirley Wind neighbors, according to documents filed last November with the PSC by the Brown County Department of Health.
Last spring, the PSC allowed Clean Wisconsin to intervene as an ally of the developers in its regulatory review of Highland Wind. In May, the organization asked the commission for $48,000 in intervenor compensation funds, provided by utility ratepayers, to measure background noise at the proposed Highland site and operational noise at a functioning wind farm, either Glacier Hills in Columbia County or Shirley Wind. According to documents Clean Wisconsin filed later with the PSC, Wisconsin Electric Power and Duke Energy, owners of the respective facilities, refused permission for on-site testing.
Ultimately, four acoustic consultants assembled from across the country settled for testing at the three abandoned homes near Shirley Wind. Not always owned by Duke Energy, the comparatively small wind farm was built by Emerging Energies of Wisconsin with eight turbines of a type considered for Highland Wind, which would use 41.
Last December the consultants—some of whom have worked predominantly for supporters of wind development, some predominantly for opponents—produced a report that became part of the PSC’s Highland Wind decision record. Inconclusive overall, it found enough unanswered questions about health consequences that all the consultants signed off on this statement:
“The four investigating firms are of the opinion that enough evidence and hypotheses have been given herein to classify LFN and infrasound as a serious issue, possibly affecting the future of the industry. It should be addressed beyond the present practice of showing that wind turbine levels are magnitudes below the threshold of hearing at low frequencies.”
Study First, Regulate Maybe
The PSC rejected Highland Wind’s application in February because two of the three commissioners doubted the project as designed would meet nighttime standards for audible turbine noise. All three made clear that ILFN wasn’t a factor, since Wisconsin has no standard. With varying degrees of enthusiasm, all agreed that research potentially identifying a standard is desirable. Commissioners invited Emerging Energies to submit a new application.
Just before the February 14 vote denying approval of Highland Wind, Commissioner Ellen Nowak said, “I think future applicants are on notice here that [ILFN is] going to be a key issue…this is an industry-wide concern.” Nowak agreed with Commissioner Eric Callisto that they “wouldn’t put the burden directly on Highland” to advance ILFN research but advocated for more being done.
Chairman Phil Montgomery agreed, saying, “This is our shot at ILFN.”
Callisto cautioned that the Shirley study yielded insufficient information to create a regulatory standard. The others agreed. Callisto pondered further research.
“If we’re going to go down that road requiring [an] additional look at ILFN, it should be a broader look,” possibly involving the Wind Siting Council that devised the current standards, “perhaps seeking funding from the Legislature or from all of the entities that we regulate in this state,” Callisto said.
He added, “There was a lot of smoke but from my perspective I’m not sure there’s a fire yet.”
Pick a Paper
A cursory search last month revealed a 2011 New Zealand study saying audible turbine noise “can negatively impact facets of health-related quality of life,” and a 2012 paper by researchers in Maine, Ontario, and Britain citing arguments that adjusting turbine-noise measurements for human hearing capacities inappropriately omits “relatively high levels” of ILFN and “has led to an underestimation of the potential for adverse health effects.”
In a 2011 paper, Massachusetts consultants examined two varieties of industrial wind turbines and said, “There should be no adverse public health effects from infrasound or low frequency noise at distances greater than [1,000 feet].” Wisconsin usually requires a 1,250-foot separation between large turbines and occupied structures.
Nobody knows if ILFN rules affecting wind farm development are coming to Wisconsin; it depends on studies not yet begun. But it’s safe to say as little as six months ago, nobody saw rules or even studies coming.
—Dave Hoopman, director of regulatory affairs, Electric Division, Cooperative Network