In Sweden, researchers analyzed measurement data from the Målarberget and Lervik wind farms and published their findings in 2026. The infrasound study concludes that modern, large-scale wind turbines can generate stronger low-frequency signals than earlier generations of turbines. Furthermore, the measurements indicate that standard calculation models may underestimate the propagation of infrasound under certain conditions. The study examined turbines featuring large rotors and heights of around 200 meters. Key factors in this context include weather, terrain, and atmospheric stratification. Consequently, these new findings have particular implications for permitting processes, setback regulations, and the assessment of potential impacts on local residents.
Infrasound study measures real signals from modern wind turbines
The study is based on measurements taken at two Swedish wind farms. In addition, the authors used a 3D model for sound propagation, thereby combining real-world data with a technical simulation.
At Målarberget, 27 Vestas V150 turbines were in operation. At Lervik, there were seven SG170 turbines. Consequently, the study focuses on large, modern turbines rather than older models.
Shutdown test distinguishes turbine noise from natural wind
Measurement points were located at varying distances from the turbines. Additionally, microphones captured very low frequencies. The results indicate that modern turbines can generate stronger infrasound signals than smaller, earlier models.
A key part of the measurement process took place at Målarberget. The turbines initially operated normally. They were then shut down while the measuring equipment continued to record data. This allowed researchers to identify the wind farm as the source.
Weather and terrain significantly affect sound propagation
Following the shutdown, the low-frequency signal dropped markedly. This indicates that the measured signal did not originate solely from natural wind noise. The infrasound study characterizes the sound as a periodic pattern.
This pattern involves recurring pressure pulses. Furthermore, these pulses are linked to the rotor’s movement and the blades passing the tower. Low-frequency pulses can propagate differently than audible sound.
Models reveal limitations of current setback assumptions
The SoundSim360 model accounts for terrain, wind direction, and atmospheric stratification. Meteorological data are also incorporated into the calculations, allowing the simulation to better approximate real-world conditions.
Low-frequency sound waves can behave differently, particularly at night. While stable air layers influence sound at ground level, wind affects its range. Therefore, a blanket setback distance provides only a rough estimate of actual exposure.
Not a health study, but important data for authorities
The study does not provide medical evidence of adverse health effects. However, it does show that modern wind turbines generate measurable infrasound. Consequently, authorities should scrutinize low-frequency signals more closely in new projects.
The infrasound study highlights, above all, a need for further technical clarification. This includes longer measurement series, nighttime measurements, and indoor data. In addition, operators should transparently provide operational data and weather profiles.