b"Energy & Utilities | Engineer InnovationNot in my backyard!How annoying is wind turbine noise, really?Although everybody is in favor of clean and green energy, when new wind turbine parks are built, nobody seems to want them in their backyard. Next to the visual pollution of the landscape, increased casualties among bird and bat populations, and the so-called shadow flicker effects, people also complain about wind turbine noise.While some residents living close to wind farms find the swoosh sound of wind turbines pleasant to hear, others complain about the noise, from it being a simple annoyance to a sleeping disturbance, and even claim to have caused health problems. Wind turbineFigure 1: Wind turbine noise levels at different distancesnoise has therefore become a controversial topic, showing that every person perceives the sound generatedlevels around it and make sure they are by them differently. not higher than the legally allowed limits. This often means that during the But what are the facts?night, for instance, wind farms need to Well, in reality, a wind turbine does notrun sub-optimally to not exceed make that much noise at all! At 300background noise levels. meters it is not louder than your average personal computer or homeSo, what's the problem? Are all those refrigerator. Of course, modern windcomplaints fake news?turbines get bigger and bigger, andWell, not exactly. Not only is the their blade tips often reach speeds(averaged) sound pressure level is higher than 200 kilometers per hourimportant, but so are transient noises (km/h), making more noise. However,and at the specific frequency content of overall sound levels still stay low. the noise generated. The transient swoosh sound, made whenever a Legislation also steps in to make sureblade passes, can indeed be annoying noise limits are not exceeded: everyto some people - especially during the type of wind turbine needs to undergonight, when other environmental noise a noise certification test according tois less present.the IEC61400-11, resulting in a sound power curve for different operationalSpecific frequencies - such as tonal wind speeds. noises - although not very loud, can be annoying. The latest edition of the Once the wind farm is operational,IEC61400-11 standard explicitly takes the there are environmental regulationsanalysis of those tonalities into that monitor the wind turbine noiseconsideration. During the night, one 21"