Resource Documents: Impacts (122 items)
Documents presented here are not the product of nor are they necessarily endorsed by National Wind Watch. These resource documents are provided to assist anyone wishing to research the issue of industrial wind power and the impacts of its development. The information should be evaluated by each reader to come to their own conclusions about the many areas of debate.
Author: White, Richard; and Bean, Katherine
On our analysis, a number of propositions emerge from the medical and scientific evidence. Some of those propositions had unanimous support by the relevant experts, and others had the support of most.
The propositions which we understand have unanimous support from the relevant experts or are not contested include the following:
- Wind turbines emit sound, some of which is audible, and some of which is inaudible (infrasound);
- There are numerous recorded instances of WTN exceeding 40 dB(A) (which is a recognised threshold for annoyance/sleep disturbance);
- There are also recorded instances of substantial increases in sound at particular frequencies when particular wind farms are operating compared with those at times when they are shut down; (Measurements undertaken at the Waterloo wind farm showed that “noise in the 50 Hz third-octave band was found to increase by as much as 30 dB when the wind farm was operational compared to when it was shut down” – Exhibit A51, p 2.)
- If it is present at high enough levels, low frequency sound and even infrasound may be audible;
- WTN is complex, highly variable and has unique characteristics;
- The amount and type of sound emitted by a wind farm at a given time and in a given location is influenced by many variables including topography, temperature, wind speed, the type of wind turbines, the extent to which they are maintained, the number of turbines, and their mode of operation;
- Wind farms potentially operate 24 hours a day, seven days a week;
- There are numerous examples of WTN giving rise to complaints of annoyance from nearby residents, both in Australia and overseas.
469. The propositions which are supported by the preponderance of relevant expert opinion, and which we accept on that basis, include the following:
- A significant proportion of the sound emitted by wind turbines is in the lower frequency range, i.e. below 20 Hz;
- The dB(A) weighting system is not designed to measure that sound, and is not an appropriate way of measuring it; (It is even acknowledged in the International Standard, ISO 1996-1 that the A-weighting system alone is “not sufficient to assess sounds characterized by tonality, impulsiveness or strong low-frequency content” – Exhibit A29, T43/8; Section 6.1; “Acoustics – Description, measurement and assessment of environmental noise – Part 1: Basic quantities and assessment procedures”, International Standard ISO (1996-1).)
- The most accurate way of determining the level and type of sound present at a particular location is to measure the sound at that location;
- The best way of accurately measuring WTN at a particular location is through ‘raw’ unweighted measurements which are not averaged across time and are then subjected to detailed “narrow-band” analysis;
- When it is present, due to its particular characteristics, low frequency noise and infrasound can be greater indoors than outdoors at the same location, and can cause a building to vibrate, resulting in resonance;
- Humans are more sensitive to low frequency sound, and it can therefore cause greater annoyance than higher frequency sound;
- Even if it is not audible, low frequency noise and infrasound may have other effects on the human body, which are not mediated by hearing but also not fully understood. Those effects may include motion-sickness-like symptoms, vertigo, and tinnitus-like symptoms. However, the material before us does not include any study which has explored a possible connection between such symptoms and wind turbine emissions in a particular population.
We consider that the evidence justifies the following conclusions:
- The proposition that sound emissions from wind farms directly cause any adverse health effects which could be regarded as a “disease” for the purposes of the ACNC Act is not established;
- Nor, on the current evidence, is there any plausible basis for concluding that wind farm emissions may directly cause any disease;
- However, noise annoyance is a plausible pathway to disease; (We note the World Health Organization has stated: “There is sufficient evidence from large-scale epidemiological studies linking the population’s exposure to environmental noise with adverse health effects. Therefore, environmental noise should be considered not only as a cause of nuisance but also a concern for public health and environmental health”– Exhibit A4, T287/5709, citing “WHO. Burden of disease from environmental noise.” World Health Organization; 2011 [viewed April 2013]; Available from: http://www.euro.who.int/en/publications/abstracts/burden-of-disease-from-environmental-noise.-quantification-of-healthy-life-years-lost-in-europe as referenced by Professor G Wittert in Exhibit 56 NHMRC Draft Information Paper: Evidence on Wind Farms and Human Health, “Expert Review: Comments in full”, National Health and Medical Research Council, February 2015, Appendix 8; and Exhibit 4, T299/6308, Reference No. 40, WHO “Burden of disease from environmental noise”. Bonn: World Health Organization European Centre for Environment and Health, 2011. Available from: http://www.euro.who.int/__data/assets/pdf_file/0008/136466/e94888.pdf.)
- There is an established association between WTN annoyance and adverse health effects (eg. this was established by the Health Canada study);
- There is an established association between noise annoyance and some diseases, including hypertension and cardiovascular disease, possibly mediated in part by disturbed sleep and/or psychological stress/distress; (This is also supported by much of the documentary material before us, including a Victorian Department of Health publication entitled “Wind farms, sound and health”, Technical Information, at 7. How can noise affect our health? – Exhibit A4, T297/6232.)
- There are as yet no comprehensive studies which have combined objective health measurements with actual sound measurements in order to determine for a given population the relationships between the sound emissions of wind turbines, annoyance, and adverse health outcomes. Indeed there is as yet no study which has given rise to a soundly based understanding of the degree to which particular types or levels of wind turbine emissions give rise to annoyance, or what levels or types of emissions are associated with what level of annoyance in the population. Because it relied on calculated rather than actual sound measurements, and was limited to the A and C-weighted systems, the Health Canada study did not do this.
Paragraphs 467–470, File Number 2015/4289
Decision and Reasons for Decision
Administrative Appeals Tribunal, Adelaide
Taxation & Commercial Division
Re Waubra Foundation (Applicant) and Commissioner of Australian Charities and Not-for-profits Commission (Respondent)
The Honourable Justice White, Deputy President
Deputy President K Bean
4 December 2017
Author: Barlas, Emre; et al.
The unsteady nature of wind turbine noise is a major reason for annoyance. The variation of far-field sound pressure levels is not only caused by the continuous change in wind turbine noise source levels but also by the unsteady flow field and the ground characteristics between the turbine and receiver. To take these phenomena into account, a consistent numerical technique that models the sound propagation from the source to receiver is developed. Large eddy simulation with an actuator line technique is employed for the flow modelling and the corresponding flow fields are used to simulate sound generation and propagation. The local blade relative velocity, angle of attack, and turbulence characteristics are input to the sound generation model. Time-dependent blade locations and the velocity between the noise source and receiver are considered within a quasi-3D propagation model. Long-range noise propagation of a 5 MW wind turbine is investigated. Sound pressure level time series evaluated at the source time are studied for varying wind speeds, surface roughness, and ground impedances within a 2000 m radius from the turbine.
Emre Barlas, Wen Zhong Shen, and Kaya O. Dag
— Department of Wind Energy, Technical University of Denmark, Kongens Lyngby, Denmark
Wei Jun Zhu – School of Hydraulic, Energy and Power Engineering, Yangzhou University, Yangzhou, China
Patrick Moriarty – National Wind Technology Center, National Renewable Energy Laboratory, Boulder, Colorado, USA
The Journal of the Acoustical Society of America 2017 Nov;142(5):3297.
Download original document: “Consistent modelling of wind turbine noise propagation from source to receiver”
Author: Palmer, William
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” 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.
Global Environment, Health and Safety 2017, Vol.1, No. 2: 12
Download original document: “Why wind turbine sounds are annoying, and why it matters”
Author: Hemmel, William
Photos by William Hemmel, Aerial Photo NH