Wind Farm Noise Assessment Case Study
Noise levels study at nearest residential properties from a proposed Wind Farm.
The proposal of building three wind turbines along a valley where the nearest residential properties are located between 800 and 1000 meters. Different noise monitoring locations were chosen at different noise sensitive residential properties. These locations-receptors were chosen as sites for background noise monitoring and for prediction and assessment of the proposed 3 wind turbines. These locations-receptors are the only noise sensitive residential properties affected by the noise from the proposed wind turbines. The wind turbine to be installed is the V01-3.8 MW, it is a wind turbine with 3x44 meters of leading edge, it has a rotor diameter of 90 meters, area swept of 6.3 m2, nominal revolutions 15.1 rpm, operational interval 8.2-16.3 rpm, number of blades 3, the tower hub height is 80 m, 105 m.
The operational data is cut-in wind speed 4. 4 m/s, nominal wind speed 15 m/s and cut-out wind speed 25m/s. We know that the main noise source from these wind turbines is the interaction of the air with the surfaces of the rotor blades with can generate low frequency noise. Different studies have marked the possible link between the low frequency noise of the type transmitted by wind farms and a rare condition called vibroacoustic disease. It has been suggested that a combination of noise (containing low frequency) and the irregular movement effects of the flickering blades (amplitude modulation) is causing some physical effect in a variety of people. This noise can be a special problem in a certain rural areas where the background noise levels are very low.
A realistic noise prediction levels causing from the proposed wind turbines can avoid future problems at nearest noise sensitive residential properties.
SSAC has assessed the noise impact of the proposed wind turbines by a combination of noise prediction levels against relevant criteria in the way of noise limits.
To assess the potential impact we have been following the methodology of ETSU-R-97. Other relevant methodology has been consulted such as BS4142.
We undertake different background noise monitoring across the most noise sensitive residential properties that will be affected by the wind turbines for a period to be representative of the typical noise background on the area. We also covered an adequately wide range of wind directions and speeds to be considered as a representative on the area. Consideration was taken to remove any effects of extraneous noise.
The prediction of the wind turbine noise levels was undertaken using the calculations method supply by the ISO 9613. The Sound Power Levels emitted by the wind turbine has been supplied by the manufactured supported by a measurement test. The final assessment showed that the noise levels predicted complied with limits derived from ETSU-R-97.