FREQUENTLY ASKED QUESTIONS ABOUT RENEWABLES

Question: Are wind turbines noisy?

...Wind Turbines whisper quietly, now...

Large, modern wind turbines have become very quiet. At distances above 200 metres, the swishing sound of rotor blades is usually masked completely by wind noise in the leaves of trees or shrubs.

There are two potential sources of noise from a wind turbine: Mechanical noise from the gearbox or generator , and aerodynamic noise from the rotor blades.

Mechanical noise has virtually disappeared from modern wind turbines. This is due to better engineering with more concern about avoiding vibrations. Other technical improvements include elastically dampened fastenings and couplings of the major components in the nacelle, and to a certain extent sound insulation. Finally, the basic components themselves, including gearboxes , have developed considerably over the years. Modern wind turbine gearboxes use "soft" gearwheels, i.e. toothed wheels with hardened surfaces and relatively elastic interiors.

Aerodynamic noise i.e. the "swish" sound of the rotor blades passing the tower of a wind turbine primarily arises at the tip and the back edge of the rotor blade. The higher the rotational speed, the louder the sound. Aerodynamic noise has been cut dramatically during the past ten years due to better design of rotor blades (particularly blade tips and back edges).

Pure tones can be very annoying to a listener, while "white noise" is hardly noticed at all. Rotor blade manufacturers take extreme care to ensure a smooth surface which is important to avoid pure tones. Likewise, manufacturers who install wind turbines take great care to ensure that the rotor blades are not damaged when a wind turbine is being installed.

Back to Page FREQUENTLY ASKED QUESTIONS
ABOUT RENEWABLES