Constable, Dr J. Moroney, Dr L. Den Brook Amplitude Modulation Noise Condition
Renewable Energy Foundation
Information Note
October 31, 2011
Introduction
The noise most commonly associated with wind farms, and frequently complained of, is the repetitive swishing beat occurring at turbine blade rotation frequency, which is known as Amplitude Modulation (AM) of the aerodynamic turbine noise. In 2007 the Government commissioned the University of Salford and the Hayes McKenzie Partnership (HMP) to investigate AM noise by means of a survey of wind farm noise complaints lodged with local authorities. At the time of publication the resulting Salford report did not reveal the names of any of the wind farms with noise problems nor the specifics of the noise complaints.
The Renewable Energy Foundation (REF) submitted a Freedom of Information request to the University of Salford to obtain this data, and following a ruling by the Information Commissioner, this data was ultimately disclosed. The survey data was published in 2009 and revealed that a significant number of noise complaints were potentially attributable to AM noise.
There has been an increasing debate, including those at Public Inquiries into proposals for specific wind farms, about the need for an AM noise condition to protect wind farm neighbours from excessive AM noise, which has been blamed for sleep disturbance.
Of particular interest is the case of the Den Brook wind farm application. This project was consented in December 2009 following a second public inquiry during which noise issues were extensively discussed. The Inspector accepted that a planning condition to prevent excessive AM noise was both necessary and reasonable, and included a new AM condition as part of the consent. …