Environmental consultants can count the minutes a home is affected by the strobelike flickers of a wind turbine’s shadow.
They can measure the decibels of the rhythmic thrum of turbine blades cutting through the air.
They can use those flicker and sound measurements to determine the best placement for wind farms.
But, wind farm developers argue, basing placement on those tests means sacrificing the one thing the industry needs to build in Wisconsin: certainty. Establishing setback distances would give developers that certainty, said Jim Naleid, managing partner for Holmen-based AgWind Energy Partners LLC.
“The problem with issues relating to sound and shadow flicker is that you run into a series of unending tests,” he said. “You don’t know at what cost those tests will come, and that’s the problem.”
It can cost as much as $15,000 and take as long as a month to run a computer program that studies the flicker, said Bryan Wheler, project manager for Hershey, Pa.-based ARM Group Inc., an environmental consulting firm that runs shadow flicker and sound tests for wind farm projects. He said sound tests take two to three months and can cost as much as $30,000.
“It’s not an unending series of tests,” Wheler said.
Those tests lend logic to turbine placement that arbitrary setbacks cannot, said Doug Zweizig, co-chairman of the state’s Wind Siting Council, which is developing turbine placement recommendations for wind farms that generate less than 100 megawatts of electricity.
“A setback is just a very crude attempt to deal with issues relating to noise and shadow flicker,” he said. “If the real problem is something like noise, then why don’t we just deal with that?”
The council, Zweizig said, will consider a proposal to restrict turbine noise and shadow flicker on properties that do not host turbines. The proposal would limit shadow flicker to 25 hours per year. It also would set a 50-decibel daytime limit and 45-decibel limit at night.
The drawback to establishing a setback distance, Wheler said, is that it could limit wind farm development. If the council, for example, established a 2,000-foot setback from property lines, he said, developers lose the opportunity to account for variables.
“What if there’s a property closer than 2,000 feet that’s down in a valley where they’ll never see shadow flicker?” Wheler said. “What if there are trees and vegetation in between the turbine and house that limits shadow flicker? You still have developers saying, ‘Well, we don’t have 2,000 feet here. Let’s move on.'”
Those variables create unnecessary complications for projects, said Jason Yates, contracts manager for Elgin-based EcoEnergy LLC. The industry needs a reliable standard, he said.
“Because maybe there are issues with 10 of 40 turbines, so you have to run a new set of tests,” Yates said. “It’s just nonending battles.”
If the council expands the guidelines beyond setback distances, Yates said, it will create more uncertainty in Wisconsin’s wind market.
That, Naleid said, would scare away developers.
“Until there is some kind of standard,” he said, “developers are not going to do business here.”