As development of utility-scale wind energy projects has increased in Minnesota, so have concerns regarding wind turbine noise. Concerns about wind turbine noise generally describe negative reactions to low-frequency sound, infrasound, and amplitude modulated audible frequencies of sound.
- Noise at lower frequencies generally travel farther (attenuate less) than high frequencies and are created directly by blades which is difficult for manufacturers to mitigate.
- Infrasound is generally defined as inaudible through conventional hearing. However, a percentage of the population may have lower thresholds for hearing low frequency noise or may sense low frequency noises though other sensing mechanisms besides conventional hearing.
- Amplitude modulated noise, analogous to continuously varying volume on speakers, may be annoying to the point at which it becomes a health concern.
These noise types and potential associated impacts to humans could potentially raise permitting costs and constitute a long-term barrier to the growth of the wind-energy industry.
In collaboration with industry partners, the Minnesota Study on Wind Turbine Acoustics (MnSoWTA) looks to analyze and characterize a comprehensive 2012 data set of audible and infrasound gathered at the St. Anthony Falls Laboratory Eolos Wind Research Field Station in Rosemount, Minnesota. The project will also additionally collect and analyze data from a Minnesota wind farm. The acoustic data will characterized and analyzed using information from literature, and under the direction of the project’s technical advisory panel, used to determine the potential impacts of wind turbine noise on humans. The project will significantly leverage the research team’s knowledge of wind turbine systems to aid this research.
By improving understanding of the sources and impacts of wind turbine sound, this project seeks to help industry and regulators better respond to the concerns of the public about potential health concerns from wind turbines. These responses include better site planning, post-construction noise monitoring, and potentially mitigation methods or technologies.
The project initiated in 2015 and will wrap up end of year 2018.
Take a tour of the Eolos Wind Energy Turbine by watching the video below