A new report by a group of Michigan State University faculty is challenging the current state-endorsed sound level for wind turbines and citing potential health risks.
The state of Michigan established sound guidelines for wind energy at 55 decibels in 2008, but local communities throughout Michigan have hotly debated the topic as wind farms begin to crop up.
The MSU report calls on the state to consider lowering the noise level to 40 decibels, after concluding that there could be potential health risks with the lower frequency noise created by large, industrial-scale turbines.
“We strongly recommend the state of Michigan consider our recommendations in revising its 2008 guideline on the placement of onshore wind turbines,” Ken Rosenman, chief of the division of occupational and environmental medicine at Michigan State University, said in a statement announcing the report. “A level of 55 decibels or higher presents unacceptable health risks.
Rosenman and the report cites research from the World Health Organization that found cardiovascular disease can result from repeated exposure to 40 decibels at night and short-term effects include sleep disturbances.
The study has already had an impact in Emmet County, where the current wind energy ordinance has been set at 35 decibels.
Copies of the new Michigan State University report were distributed to members of the Emmet County Planning Commission last week.
“It definitely seems to support our position,” said Tammy Doernenburg, Emmet County Planning and Zoning director, adding that the planning commission also seemed to think it supported the current ordinance level.
Doernenburg said she didn’t know whether the planning commission would revisit the issue specifically because of the study.
In April, the Emmet County Zoning Ordinance Advisory Committee decided to stand firm on the wind energy ordinance of 35 decibels and its 400-foot height restriction. Changes and decisions to the overall county ordinance are expected to be finalized in October.
Wind developers have contested the 35 decibel level in Emmet County amounts to exclusionary zoning, because it would severely limit what could potentially be built within the zoning boundaries.
The guidelines in Emmet County have effectively stalled a $150 million proposed wind farm in Bliss and Carp Lake townships that Balance 4 Earth, a developer out of southeast Michigan, estimates would generate up to $1 million per year in tax revenues for the area.
While the report recommends a lower sound level for industrial turbines, the study does not review smaller, home use turbines.
In a follow up email, report co-author Jerry Punch – a retired MSU professor of audiology – said there has “generally not been many complaints or issues raised regarding noise levels generated by smaller, single-home turbines, but concern with noise from industrial-scale turbines has been widespread in Australia, European and Scandinavian countries, and the U.S.”
Punch said the report focuses strictly on negative health effects attributed to the high-intensity, low frequency sound and infrasound created by large turbines of 1-1.5 megawatts.
Small wind turbine developer, Lake Effect Energy Corporation in Harbor Springs, recently filed a request with the Michigan Attorney General’s Office requesting an investigation be conducted into potential illegal actions in the development of the county wind ordinance. However, because the case is a criminal investigation, a spokesperson for the Attorney General confirmed the case has been filed, but said the details of the investigation are not available while the case is ongoing because of its nature.