Last update: December 13, 2017

iMedPub Journals 2017: Vol.1 No.2:12 Canada

Why Wind Turbine Sounds are Annoying, and Why it Matters

Some consider “annoying” has little impact more than, “your gum chewing is annoying,” while for others, an annoying sound can mean loss of sleep, and loss of that restorative time itself has many documented adverse effects.

Wind turbine noise measurement

Research Article
iMedPub Journals
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Global Environment, Health and Safety

Author: Palmer WKG, TRI-LEA-EM, 76 Sideroad 33-34, RR 5, Paisley, ON N0G 2N0, Canada, Tel: (519) 353-5921, E-mail: trileaem@bmts.com

Published date: November 07, 2017

Copyright: © 2017 Palmer WKG. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

Almost without hesitation, most people can identify a sound that is annoying to them, whether it might be fingernails on a chalkboard, a barking dog late at night, a mosquito buzzing in their ear, or their own particular example. Classic acoustics texts identify key points related to annoyance. These "special characteristics of noise" include tonality, a non-random cyclical nature, pitch, roughness, rise time, and dominance of noise during sleeping hours when environmental noises diminish. A new source of environmental sound arises from wind turbines, a rapidly growing method of generating electricity. Studies such as the “Health Canada Wind Turbine Noise and Health Study” [1] have documented noise annoyance complaints. This paper categorizes wind turbine noise complaints based on face-to-face interviews with impacted individuals, and correlates logs of complaints to conditions at the time. Recordings made in a controlled manner of environmental sound samples, such as flowing streams, wind in coniferous trees, or wind in bare or leafed deciduous trees as well as other sounds found in the environment, such as vehicles passing by on highways, aircraft overhead, and railway travel are compared with sound recordings from wind turbines. The comparisons included analysis of LZeq, LAeq, narrow band analysis, evaluation of amplitude and frequency modulation, and fluctuation strength. Development of modifiers to normal LAeq sound limits is suggested to improve the effectiveness of regulations. A key finding shows annoyance is related more to changes and characteristics at a particular time, rather than to longterm averages of sound. Why annoying sounds matter is a complex subject. Some consider “annoying” has little impact more than, “your gum chewing is annoying,” while for others, an annoying sound can mean loss of sleep, and loss of that restorative time itself has many documented adverse effects.

Introduction

The subject of annoyance from noise has been discussed by many, including Kryter [2] in, "The Effects of Noise on Man" as well as Fastl and Zwicker [3] in, "Psychoacoustics-Facts and Models". A new source of sound in the environment, not discussed in these classic texts arises from wind turbines, a rapidly growing method of generating electricity. The Global Wind Energy Council [4] shows there were 341,320 wind turbines in operation in the world at the end of 2015, with a global capacity of 486.8 GW, which produced 3.7% of the Global Electricity Supply. Most of the examples in this paper are chosen from data for the Canadian Province of Ontario. In Ontario the number of wind turbines increased from 1 to roughly 2500 from 2001 to 2016. The connected MW wind turbine nameplate capacity [5] in the latest year (4821 MW in 2016) could amount to about 31% of the annual average Ontario electrical demand (137 TWh) if operated at capacity, although these wind turbines generated about 6% of the Ontario yearly electrical energy output. Studies such as the “Health Canada Wind Turbine Noise and Health Study”[1] or the Council of Canadian Academies “Wind Turbine Noise and Human Health” [6] study have documented complaints about noise annoyance from wind turbines impacting the environment, even while they were intended to be environmentally friendly. Witnesses have testified under oath to Ontario Environmental Review Tribunal [7] hearings of adverse health impacts they experienced after wind turbines started up in their environment.

While the classical texts [2,3] clearly identify the "special characteristics of noise" that increase annoyance, such as tonality, a non random cyclical nature, and dominance of noise during sleeping hours when environmental noises diminish, they are less clear about measures that can be used to assess the “special characteristics” to ensure that regulations are effective at protecting the public from the adverse impacts of noise annoyance. This paper describes recordings made in a controlled manner of a number of environmental sound samples, such as flowing streams, lake waves, crops in fields, wind in coniferous trees, or wind in bare or leafed deciduous trees. Recordings were also made of other sounds found in the environment, such as vehicles on highways, aircraft, and railways. These sounds were compared with sound recordings from wind turbines. The comparisons included analysis of LZeq, LAeq, narrow band analysis, and an evaluation of amplitude modulation, and fluctuation strength. Interviews with people identifying adverse impact and some complaint log files were examined to categorize the most annoying aspects of the noise. The annoying aspects were compared to the features identified in the comparisons between wind turbine sound recordings, and the recordings from other sound samples.

The paper identifies measures for some of the special characteristics that can be correlated to the changes in annoyance level. Development of promising modifiers to normal LAeq sound limits, as from cyclical nature, tonality, and dominance compared to background are suggested to improve the effectiveness of regulations. A key recognition is that annoyance is related more to changes and characteristics at a particular time, rather than to long-term averages of sound.

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