Sound emissions from wind turbines are regulated by the decree of August 26, 2011.
The noise of a wind turbine is 55 dBA directly underneath, 30-40 dBA at 500 meters, and 20 dBA at 1 km. This noise has two origins: the friction of the blades with the wind (“aerodynamic” noise) and the mechanical vibrations between the components of the turbine.
The resulting noise pollution is among the criticisms of opponents of wind power development in France (although far behind landscape impact or energy considerations).
Noise Levels Depending on Distance
Directly Under a Turbine:
At the foot of a wind turbine, the noise averages 55 decibels (dBA), which is almost the equivalent of the “noise of a busy market” according to Engie Green.
At 500 Meters:
French law prohibits the installation of wind turbines within 500 meters of any dwelling. At this mandatory minimum distance, the noise of wind turbines is reduced on average between 30 dBA and 40 dBA, which is the sound level of a conversation in a low voice according to ADEME. It should be noted that this noise varies depending on the wind but also on the environment of the site where the wind turbines are installed (topography, vegetation, urban planning, etc.).
At 1 Kilometer:
At a distance of one kilometer, a wind turbine produces a noise of about 20 decibels, comparable to that of a light wind.
What Does French Regulation Say?
Wind turbine sound emissions are regulated by the decree of August 26, 2011 (article 26) which sets, in so-called “regulated emergence” zones (inside homes or building zones), a threshold of “noise emergence” if the ambient noise level (noise including the background noise of the site and that of the wind farm) exceeds 35 dBA: the difference in noise when the wind farm is operating or stopped must not exceed 5 dBA during the day (between 7 am and 10 pm) and 3 dBA at night (between 10 pm and 7 am).
At the edge of the park perimeter, as defined by the decree, the maximum noise level must not exceed 60 dBA at night and 70 dBA during the day.
An acoustic study is carried out before the installation of a wind farm. Exceeding the mandatory thresholds after commissioning may force an operator to restrict or shut down wind turbines during “critical” periods identified during the study (particular wind directions and/or speeds).
Ongoing Studies:
Some concerns have also been raised about infrasound (frequencies below 20 Hz) and low-frequency sound emitted by wind turbines (the nuisance associated with audible noise mainly concerns frequencies above 50 Hz). According to ANSES (National Agency for Health Safety), the studies currently available do not, however, “provide sufficient scientific evidence in favor of the existence of health effects related” to these infrasounds.
Several research projects on wind turbine noise are underway in France: Cerema is piloting the “PIBE” project (Predicting the Impact of Wind Turbine Noise) until early 2023, which aims to improve methods for predicting the noise impact of wind turbines by studying new noise reduction solutions. The “RIBeolH” project, led by Gustave Eiffel University, is interested in the impact of wind noise effects on human health and the perception of low frequencies.
Sources : Connaissance des Energies