Resource Documents: Noise (644 items)

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Also see NWW press release on noise

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Effect of unsteady flow on wind turbine wake development and noise generation

Author:  Sedaghatizadeh, Nima

«The results of this study show that underlying mechanism associated with the perceived noise in the far-field of the turbine blades is amplitude modulation due to partial stall on the blades or interaction of the blades with incoming turbulent structures. This is in contrast with the common belief of trailing edge noise to be the dominant source for the perceived noise and its amplitude modulation due to rotation of the blades. Moreover, it is observed that the majority of the locations in which the noise from whole turbines is perceived by the community, are in close proximity of the wake region. … Results revealed that, the highest noise level in the vicinity of a wind turbine corresponds to blade pass frequency and is due to amplitude modulation of the trailing edge noise caused by the rotation of the blade, as well as blade tower interaction. Results also showed that the emitted noise is refracted due to the wind shear in atmospheric boundary layer, as well as the wake and associated turbulent structures. The [computational fluid dynamics] outcomes showed that the wake breakdown occurs at a distance of 12 diameters downstream of the turbine with a strong downwash due to longitudinal vortices. Contours of sound pressure level at the breakdown location of the wake of the wind turbine showed refraction and modulation of the sound at this location. Results also revealed refraction of the noise towards the ground and wider areas due to existence of the longitudinal vortices.»

Nima Sedaghatizadeh
School of Mechanical Engineering, University of Adelaide, Australia
Thesis submitted in fulfilment of the requirements for the degree of Ph.D. in Mechanical Engineering

Download original document: “The effect of unsteady flow on wind turbine wake development and noise generation”

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Recent developments in the regulation of noise from wind energy facilities in Victoria

Author:  Asten, Heidi; Tarasenko, Ellen; and Ellicott, Thomas

Wind energy facility proponents should take note of recent developments in the regulation of noise impacts from wind energy facilities in Victoria, which signal increased scrutiny of noise impacts from operations. This includes:

• South Gippsland Shire Council’s finding of statutory nuisance under the Public Health and Wellbeing Act 2008 (Vic) (PHW Act) in relation to the Bald Hills Wind Farm;

• The impending introduction of the general environmental duty in relation to noise under the Environment Protection Act 2017 (Vic); and

• The Victorian Civil and Administrative Tribunal’s (VCAT) consideration of the application of the high amenity noise limit under the New Zealand Standard Acoustics – Wind farm noise NZS 6808:2010 (2010 NZS) to the Farming Zone in Naroghid Wind Farm Pty Ltd v Minister for Planning [2019] VCAT 800 (3 June 2019) (Naroghid).

These developments highlight the significance of proactive and robust management of noise impacts for both existing and proposed wind energy facilities.

South Gippsland Shire Council’s investigation of Bald Hills Wind Farm under the PHW Act

In March 2019, the South Gippsland Shire Council (Council) determined that the Bald Hills Wind Farm had caused nuisance under the PHW Act as a result of noise from the operation of its wind turbines. The decision followed a Supreme Court of Victoria ruling requiring the Council to engage an independent health assessor to consider the complainants’ concerns.

In reaching its finding that a nuisance had been caused, the Council attributed weight to noise logs, and evidence of health impacts provided by the complainants. Significantly, the decision was made notwithstanding reported compliance with the noise conditions of the planning permit for Bald Hills Wind Farm. The lack of directly comparable data correlating timing, location and nature of noise emissions between the formal noise compliance monitoring and the noise complaints presented some challenges to all parties.

The decision is the first finding of nuisance under the PHW Act in relation to noise from the operation of wind turbines. The decision has not been appealed, and may set a precedent for other local government authorities in PHW Investigations. Our key observations in relation to the decision are:

• Compliance with planning permit conditions does not necessarily preclude a finding of nuisance under the PHW Act in relation to noise from wind energy facilities;

• Evidence of impacts on sleep, and corroboration by an independent expert of high levels of audible noise from wind turbines within dwellings was central to the finding of nuisance;

• Wind energy facility proponents may wish to consider whether their post-construction monitoring addresses consideration of any noise complaints they receive; and

• Wind energy facility operators will need to engage with complainants and councils if nuisance complaints are made under the PHW Act.

The new general environmental duty

The Environment Protection Act 2017 (Vic) will require wind energy facilities to comply with a new ‘general environmental duty’ (GED) when it comes into effect (along with a whole suite of other reforms), currently expected to be in mid-2020. The GED will operate separately from planning permit requirements, and from noise nuisance considerations, including under the PHW Act.

The GED will require that ‘a person who is engaging in an activity that may give rise to risks of harm to human health or the environment from pollution or waste must minimise those risks, so far as reasonably practicable’. Significantly, ‘human health’ is defined to include ‘psychological health’. The GED will require management of noise impacts from operations, given that the definition of ‘pollution’ includes noise pollution. A person commits an offence if they contravene the GED in the course of conducting a business undertaking.

The Environment Protection Authority (EPA) will have primary responsibility for regulating the GED. However, third parties may also bring actions for breach of the GED in some circumstances, and seek civil and compensation orders in respect of injury, loss or damage resulting from a contravention.

Wind energy facility operators should consider:

• What are the risks of harm to human health or the environment from operation of the wind farm, including in respect of noise?

• To what extent can the risk of harm be avoided, and has this been done so far as reasonably practicable?

• To what extent can the risk of harm be mitigated, and has this been done so far as reasonably practicable?

• To what extent are their procedures to engage with the local community effective in resolving issues or complaints that may arise during operation?

The EPA is yet to release detailed guidance as to how it intends to regulate the GED, including in the context of wind energy facilities. Once released, such guidance will be an important means of understanding the EPA’s likely approach. The EPA will also be releasing subordinate legislation under the new regime, including environmental reference standards which will regulate noise emissions and replace existing State environment protection policies.

The Naroghid decision

In Naroghid, VCAT considered a planning permit application for a 12 turbine wind energy facility in Corangamite, in the vicinity of Cobden.

VCAT refused to grant a permit for the wind energy facility on a number of grounds. However, of broader relevance to the industry, the decision provides a discussion of the application of the high amenity noise limit under the 2010 NZS to the Farming Zone. The high amenity noise limit under the 2010 NZS applies a limit of 35dB or background +5 dB, as opposed to 40dB or background +5 dB in other areas under the 2010 NZS.

While the Tribunal did not make a final ruling on the issue, it expressed the view that the high amenity noise limit should apply to non-stakeholder dwellings in the Farming Zone. The discussion on this point is contrary to the finding in another VCAT decision in Cherry Tree Wind Farm Pty Ltd v Mitchell SC & Ors (Includes Summary) (Red Dot) [2013] VCAT 521 that the high amenity noise limit does not apply in the Farming Zone. While the Tribunal in Naroghid agreed that the planning scheme is the relevant ‘plan’ relevant to application of the NTS 2010 in this context, the Tribunal’s discussion went on to attach particular weight to EPA Publication 1411 Noise from Industry in Regional Victoria (October 2011). Based on the approach to noise amenity in NIRV (a reference document in the Planning Scheme which is currently being updated), the Tribunal suggested that a high amenity noise limit should be applied to the Farming Zone.

While the discussion in Naroghid is not authority for the application of the high amenity noise limit to the Farming Zone, wind energy facility proponents may wish to consider noise compliance risks at dwellings within the 35dB noise contour.

Herbert Smith Freehills LLP – Heidi Asten, Ellen Tarasenko and Thomas Ellicott
August 30 2019 lexology.com

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Bald Hills noise monitoring data

Author:  Thorne, Bob; and Noise Measurement Services

Bald Hills Wind Farm Summary Report (45.04 MB) [alt. link]

Bald Hills Noise Monitoring PTR Data: “The 40 dB(A) noise limit is exceeded on the days coloured ‘peach’/’transparent red’ (PTR)”

• May 2018 (11.31 MB) [alt. link]
• June 2018 (22.01 MB) [alt. link]
• July 2018 (10.88 MB) [alt. link]
• August 2018 (14.50 MB) [alt. link]
• September 2018 (12.87 MB) [alt. link]
• October 2018 (11.87 MB) [alt. link]
• November 2018 (10.88 MB) [alt. link]
• December 2018 (6.32 MB) [alt. link]
• January 2019 (5.35 MB) [alt. link]
• March 2019 (6.31 MB) [alt. link]

Bald Hills Noise Diary Analysis May 2018 to March 2019 Final.xlsx (0.29 MB) [alt. link]

Comparison of wind vs special audible characteristics (SACs) vs power generation (SCADA), May-Sept 2018 (5.64 MB) [alt. link]

Bald Hills Wind Farm Video (141.79 MB) [alt. link]:

Sample noise event charts (colour dots represent noise complaints):

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Silent Menace (Part 1 of 2): Wind Turbine Infrasound – What You Can’t Hear Can Hurt You

Author:  Deever, Donald Allen

June 1, 2019 – Desert Report: Sierra Club California/Nevada Desert Committee

Sci-fi fans remember the tagline from the Alien movie poster, which ominously declared, “In space, no one can hear you scream.” Likewise, research on the infrasound frequencies produced by industrial wind turbine blades is increasingly providing proof that what you can’t hear, can hurt you. Accordingly, it is worth noting that there is a huge difference between the auditory terms “sound” and “noise.” According to the Canadian Centre for Occupation Health and Safety, “Sound is what we hear. Noise is unwanted sound.” When speaking of the sounds generated by industrial wind turbines, the operative term is “noise,” and an important difference between sound and noise – including when infrasound noise is not heard by the ears – is that it can be felt by the brain and internal organs. Such an insight makes it all the worse to learn that infrasound noise can travel over much longer distances than previously admitted by the wind energy industry. Moreover, the intensity of potentially harmful levels of infrasound vibrations do not dissipate as quickly as formerly believed.

Along those lines, an important German study calculated the distances over which wind turbines can have unanticipated effects. The 2016 study warned how wind turbine-produced infrasound interferes with Comprehensive Nuclear Test-Ban Treaty monitoring equipment that is operated by Germany in the Bavarian Forest and Antarctica. The purpose of those stations are to verify compliance with the International Monitoring System that exists to detect nuclear explosions occurring in the atmosphere.[1] The conclusion of that study suggested that a distance of 20 kilometers between a single wind turbine and the monitoring stations should be considered a rule of thumb and that a separation of 50 kilometers should be maintained between multi-element wind energy facilities and monitoring stations. The introduction to that article tells of a variety of studies that already took place to identify the hazards that wind turbine infrasound were already wreaking on similar monitoring stations on Ascension Island, as well as a station in southern California where the monitoring equipment is located 35 kilometers from a so-called “wind farm.” Moreover, the historical portion of that study mentioned, “Wind turbine noise effects on seismometer stations have also been investigated and reported for example at AS104 station in Eskdalemuir, UK. Stammler and Ceranna investigate the increasing influence of wind turbines on seismic records, depending on the wind speed and on the number of newly build wind turbines in the vicinity of seismic sensors.” This suggests that wind turbine infrasound could interfere with the monitoring and prediction of earthquakes and associated tsunami warnings.

The great distances that infrasound waves travel from their source was also documented in a study by the Los Alamos and Sandia Laboratories, published in 2014.[2] In New Mexico, infrasound from sixty wind turbines could be detected 90 kilometers from the source under favorable conditions at night. The present trend of the wind energy industry is to push for more offshore than onshore facilities, yet studies in acoustics show that sound waves travel further over water than land, and that cooler water temperatures create inversions that cause sound waves to bend downward and become amplified which is a thought that leads to a study in Finland.

A 2016 Finnish pilot study belatedly made international news in 2018, when the Finnish Association for Environmental Health studied 200 persons affected by wind turbine infrasound. The report showed the severity of adverse health symptoms did not decrease for the first 15 kilometers from the source. It also determined that the effects were not correlated with the expectations of the persons being studied. This represented a major finding, since few countries require more than a 2 kilometer setback of wind turbines from homes.[3] The results of the Finnish study should not have been a surprise among occupational medical health professionals. In 1999, a report was published by the International Journal of Occupational Medicine and Environmental Health,[4] which stated, “Owing to its long wavelength, infrasonic noise is less attenuated by walls and other structures, it is able to propagate over long distances and may affect the human organism even though the latter is far from its source.”

In light of the proliferation of wind energy, one might ask, “How long have the negative effects of wind turbine-generated infrasound been known?” The first solid evidence for estimating the levels of annoyance from infrasound on humans was found thirty-two years ago. In 1987, Neil Kelley pioneered the field of wind turbine noise annoyance when he presented a study at the WindPower ’87 Conference and Exhibition in San Francisco.[5] His lecture was titled A Proposed Metric for Assessing the Potential of Community Annoyance from Wind Turbine Low-frequency Noise Emissions. That research was carried out at the Solar Energy Research Institute in Golden, Colorado, and sponsored by the U.S. Department of Energy. Kelly’s lab-based report directly linked infrasound to annoyance among human subjects, thereby indirectly linking stress-related disorders from annoyance to wind turbine infrasound.

Since infrasound lies in the inaudible frequency range of less than 20 Hertz, “What you can’t hear, can’t hurt you” was a mantle of protection the wind industry hid under for decades. Few governments embrace the concept of wind energy as enthusiastically as Germany, yet a highly-publicized 2017 report from their Max Planck Institute found that infrasound, even though it is inaudible, can produce measurable effects in recorded brain function.[6] According to their report, “this study is the first to demonstrate that infrasound near the hearing threshold may induce changes of neural activity across several brain regions, some of which are known to be involved in auditory processing, while others are regarded as key players in emotional and autonomic control.”

This 2017 study from the Max Planck Institute, “Altered Cortical and Subcortical Connectivity Due to Infrasound Administered Near the Hearing Threshold – Evidence from fMRI”, also broached the topic of increased cortisol secretions that occur as a result. According to the authors of that report, “since the brain’s response to prolonged near-threshold IS [infrasound] involves the activation of brains areas which are known to play a crucial role in emotional and autonomic control, a potential link between IS-induced changes of brain activity and the emergence of various physiological as well as psychological health effects can be established.”

Citing earlier research, the authors stated, “It has been reported in several studies that sustained exposure to noise can lead to an increase of catecholamine and cortisol levels. In addition, changes of bodily functions, such as blood pressure, respiration rate, EEG patterns and heart rate have also been documented in the context of exposure to below- and near-threshold IS (infrasound).” The references to those citations are contained in that study. Equally enlightening is a study that was published fifteen years earlier (2002) in Sweden, “Low Frequency Noise Enhances Cortisol Among Noise Sensitive Subjects During Work Performance.”[7]

Pre-dating the research from the Max Planck Institute, back in 1985, infrasound was similarly found to increase secretions of the hormone cortisol (causing a flight or fight response), which, at sufficiently high levels, can stress the body and mind to trigger annoyance, apathy, confusion, fatigue, an inability to concentrate, and painful pressure in the ears, all of which represents merely short term symptoms. Too much cortisol in the long term eventually weakens immunosuppressive action, weight gain, brain damage, hyperglycemia (elevated blood sugar levels that lead to diabetes), and a shut down of digestive and endocrine functions. In the end, prolonged cortisol production can lead to hypertension.[8] Fast-forward approximately 25 years to 2011, when Canada’s Environmental Review Tribunal made history by officially declaring that the health debate is no longer whether wind turbine noise is harmful to human health but has evolved into one of the degree of harm, Erickson v. Director, Ministry of the Environment. 2011. Environmental Review Tribunal Nos. 10-121 and 10-122.[9] A simple experiment to witness the end of the debate over wind turbine noise can be seen by going to Google Scholar and observing the results from searching the terms “wind turbine” AND “health effect” together.[10]

On January 26, 2019, congratulations were issued by Cape Cod Wave Magazine to the people of Falmouth, Massachusetts, following their long fight to win a court decision to have a wind energy facility removed from their town. The courts sided with neighbors when it was demonstrated beyond a reasonable doubt that the harmful effects of infrasound emanating from the wind turbines did not justify their existence, and therefore the company was ordered to cease operations and dismantle the towers.[11] Such a legal pronouncement indicates that an understanding concerning the adverse effects of industrial wind turbines has advanced beyond the realm of political opinion and moved into the arena of evidence.

Next month: Part 2 of this series will explore research on potentially harmful effects on animals, pets and wildlife, and will look at the facts or fantasy of President Donald J. Trump’s recently criticized comment that wind turbine infrasound can cause cancer.

Dr. Donald Allen Deever is a former park ranger, science teacher, flight instructor, freelance journalist, and PhD with majors in nursing education, software development, and writing pedagogy. He recently helped defeat the Crescent Peak Wind project in Southern Nevada, one of the most misplaced wind energy developments in history. He and his wife live in Searchlight on their own ten-acre nature preserve.

Download original document: “Silent Menace (Part 1 of 2): Wind Turbine Infrasound – What You Can’t Hear Can Hurt You”

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