Short answer
Wind turbines make sound, but how much depends on factors such as wind speed, distance, terrain, weather conditions and the turbine model. In Sweden, the guideline value is 40 dBA at homes. This corresponds to a sound level that is often audible but that, according to the Swedish Environmental Protection Agency, has not been shown to cause more serious health effects. At the same time, research shows that some people experience wind turbine sound as disturbing, especially if the sound is recurring or clearly audible in an otherwise quiet environment.
Why is this discussed?
Common misconceptions
"Wind turbines make the same amount of sound all the time"
The sound varies depending on factors such as wind speed, wind direction, terrain and weather conditions. When there is too little wind, the turbines produce no electricity, or very little, and the sound level is low. Under some wind conditions, the sound may be heard more clearly, while at other times it is masked by natural sounds such as wind in the trees.
"It is not possible to control how much sound wind turbines make"
Sound from wind turbines is calculated before a project receives a permit. In Sweden, established calculation models, especially Nord2000, are used to assess how sound spreads across the landscape. After the turbines have been built, sound levels can be followed up with control measurements. If the applicable conditions are not met, supervisory authorities can require measures to be taken.
What do the facts say?
Wind turbines produce audible sound
Most of the sound from modern wind turbines is generated when the rotor blades move through the air. The sound is often described as a swishing or whooshing sound. How clearly it is heard is affected by factors such as distance, terrain, weather and background sound, such as wind in trees and vegetation.
The Swedish Environmental Protection Agency recommends that sound from wind power at homes should not exceed 40 dBA. This level is often audible and may be perceived as disturbing, but scientific studies have not shown that wind turbine noise at these levels causes more serious health effects.
Perceived annoyance is about more than decibels
Research shows that wind turbine noise is often perceived as more disturbing than, for example, traffic noise at the same sound level. At the same time, the experience is influenced by more factors than the sound itself. Landscape, visibility, attitudes to wind power and the experience of having received information and the opportunity to influence the process also matter.
Studies show that people who can see wind turbines from their homes, or who highly value quiet surroundings, more often report annoyance. Research also suggests that perceived annoyance may decrease when people trust the process and feel that they have been involved in decisions that affect their immediate surroundings.
Sound is measured, monitored and weighed against other public interests
Before a wind power project is established, detailed sound calculations are carried out, taking into account factors such as terrain, weather conditions and the turbines’ sound data. After commissioning, sound levels can be checked through measurements and follow-up in accordance with the permit conditions.
Like other infrastructure, wind power affects its surroundings. In spatial planning, the question is therefore not only how much an installation affects people, but also how that impact relates to the benefit. For wind power, this often means weighing impacts on the landscape, sound environment and the wellbeing of nearby residents against, for example, energy supply and climate benefits. This is why Swedish permitting processes include extensive assessments of noise, natural values and people’s living environment.
What affects the assessment?
- Distance to the turbine – the sound level decreases with distance.
- Wind and weather – wind direction, temperature and humidity affect how sound spreads.
- Terrain and ground conditions – forest, elevation differences and ground type affect sound propagation.
- Turbine design – different models have different sound characteristics.
- Background sound in the surroundings – wind in trees, traffic or other sound sources can make the sound seem more or less clear.
