Are onshore wind turbines noisy?

Nearly everything with moving parts makes noise, and wind turbines are no exception. Wind farms are very quiet compared to other industrial facilities, but they do produce low-level noise.

Question:

Are onshore wind turbines noisy?

Fact:

Wind turbines make low-level noise while in operation, but onshore wind farms are always designed to minimise noise to the surrounding environment. Government regulations require that onshore wind farms are built at least 500 metres from the nearest residence.

Turbine noise explained

A wind turbine generates two kinds of noise. The first is an aerodynamic “whooshing” sound which is created when the turbine blades pass through the air.

The second noise is mechanical hum that is caused by the generator in the turbine’s nacelle – the large box positioned at the top of the turbine behind the rotors.

Well-designed wind turbines are relatively quiet while they are in operation, producing noise at about 35-45 decibels (dB) at a distance of 500 metres from a turbine.

Compared to other commonly heard noises, that is quite low: the noise from an electric tea kettle can range from 79 to 95 dB, a truck driving 30mph comes in at about 65dB, the sound from a kitchen refrigerator is about 50dB, and a quiet office can hum at about 40dB.

Assessment & action

While wind turbines produce low-level sound, studies have shown that the noise from wind turbines does not have negative health impacts at a safe distance.

There is, according to a comprehensive review of environmental noise guidelines for Europe published by the World Health Organisation in 2018, very little evidence available showing adverse health effects of continuous exposure to wind turbine noise. ¹

Furthermore, the WHO estimate the “burden on health from exposure to wind turbine noise at the population level to be low.”²

Background noise monitoring and extensive studies are carried out when wind farms are planned to identify the best location for turbines, so that sites are designed to minimise or eliminate any potential disruptions to residents.

At Ørsted, as part of the development of an onshore wind farm project, we always conduct an Environmental Impact Assessment (EIA) and prepare an Environmental Impact Assessment Report (EIAR).

Through that process we identify any potential noise sensitive locations and design the layout of the turbines to minimise noise levels.

We adhere to Ireland’s Wind Energy Guidelines which specify that wind turbine noise should not exceed 45 decibels at sensitive receptors.

Due to strict limitations in Ireland, the closest that a wind turbine can be built to a house is 500 metres. At that distance, noise levels drop to about 35-45 dB.

However, recent projects in Ireland have placed a setback distance of 700 to 800 metres between turbines and residential properties to assure that noise levels are reduced at nearby properties as much as possible.

Decibel levels of an onshore wind turbine

Wind often noisier than the turbines

As the wind energy industry has matured over the last few decades, manufacturers have made great strides minimising the amount of noise the turbines generate.

The soundproofing on nacelles has vastly improved since earlier models, blades have become much more efficient, resulting in less aerodynamic noise, and gearboxes are now designed for quieter operation.

As a result, the noise generated by turbines has been reduced substantially in recent years and often the wind itself is noisier than the turbine.

An image rendering of turbine noise emissions from one of Ørsted’s onshore wind farms.

Sources
1) WHO Environmental noise guidelines for the European Region, pg. 84 Environmental noise guidelines for the European Region (who.int)
2) Ibid.