Noise levels rise as wind speeds increase. When wind speeds are high, turbine noise is masked by wind-induced noises, particularly of trees being blown. Noise from modern wind turbines is essentially broad band in nature, in that it contains similar amounts of noise energy in all frequency bands.
To set this in context, Government data1 indicate that the sound of a wind turbine generating electricity 300 metres away is likely to be the same level as noise from a flowing stream 50-100 metres away, or comparable to the noise of leaves rustling in a gentle breeze. This is similar to the sound level inside a typical living room with a gas fire switched on, the reading room of a library or an unoccupied, quiet, air-conditioned office.
To protect residential amenity and sleep disturbance there are strict guidelines on wind turbines and noise emission.
In our proposed development, the turbines have been designed and located to minimise noise levels at nearby houses. Accordingly, it is anticipated that the turbines will operate within the limits set in the Government’s guidelines on noise.
To ascertain this, an assessment is being made of noise impact arising from the construction and operation of the proposed turbines. This will include comprehensive monitoring and will determine daytime and night-time criteria for noise levels at nearby houses or other selected properties. This will endeavour to ensure that neither the sleep of local residents nor the amenity of the area is disturbed.
Information derived from ODPM Planning for Renewable Energy - A Companion Guide to PPS22, Technical Annex: Wind, HMSO, 2004.