Papers on wind turbine noise

This is a list of papers on wind turbine noise. The list is not complete, and will most likely be updated in future in order to make it more thorough and more representative.

Update (November 13, 2012): Hubbard & Shepherd (1991), Jakobsen (2005), Pedersen & Larsman (2008), Pedersen et al. (2009), Hessler et al. (2008), Knopper & Ollson (2011), and Bolin et al. (2011) added. Thanks to Martin for pointing these out (in private communication).
Update (November 7, 2012): Taylor et al. (2012) added.

The influence of negative oriented personality traits on the effects of wind turbine noise – Taylor et al. (2012) “Concern about invisible environmental agents from new technologies, such as radiation, radio-waves, and odours, have been shown to act as a trigger for reports of ill health. However, recently, it has been suggested that wind turbines – an archetypal green technology, are a new culprit in explanations of medically unexplained non-specific symptoms (NSS): the so-called Wind Turbine Syndrome (Pierpont, 2009). The current study assesses the effect of negative orientated personality (NOP) traits (Neuroticism, Negative Affectivity and Frustration Intolerance) on the relationship between both actual and perceived noise on NSS. All households near ten small and micro wind turbines in two UK cities completed measures of perceived turbine noise, Neuroticism, Negative Affectivity, Frustration Intolerance, attitude to wind turbines, and NSS (response N = 138). Actual turbine noise level for each household was also calculated. There was no evidence for the effect of calculated actual noise on NSS. The relationship between perceived noise and NSS was only found for individuals high in NOP traits the key role of individual differences in the link between perceived (but not actual) environmental characteristics and symptom reporting. This is the first study to show this effect in relation to a so called ‘green technology’.” Jennifer Taylor, Carol Eastwick, Robin Wilson, Claire Lawrence, Personality and Individual Differences, http://dx.doi.org/10.1016/j.paid.2012.09.018.

Effects of industrial wind turbine noise on sleep and health – Nissenbaum et al. (2012) “Industrial wind turbines (IWTs) are a new source of noise in previously quiet rural environments. Environmental noise is a public health concern, of which sleep disruption is a major factor. To compare sleep and general health outcomes between participants living close to IWTs and those living further away from them, participants living between 375 and 1400 m (n = 38) and 3.3 and 6.6 km (n = 41) from IWTs were enrolled in a stratified cross-sectional study involving two rural sites. Validated questionnaires were used to collect information on sleep quality (Pittsburgh Sleep Quality Index – PSQI), daytime sleepiness (Epworth Sleepiness Score – ESS), and general health (SF36v2), together with psychiatric disorders, attitude, and demographics. Descriptive and multivariate analyses were performed to investigate the effect of the main exposure variable of interest (distance to the nearest IWT) on various health outcome measures. Participants living within 1.4 km of an IWT had worse sleep, were sleepier during the day, and had worse SF36 Mental Component Scores compared to those living further than 1.4 km away. Significant dose-response relationships between PSQI, ESS, SF36 Mental Component Score, and log-distance to the nearest IWT were identified after controlling for gender, age, and household clustering. The adverse event reports of sleep disturbance and ill health by those living close to IWTs are supported.” Michael A Nissenbaum, Jeffery J Aramini, Christopher D Hanning, Noise & Health, 2012, 14, 60, 237-243, DOI: 10.4103/1463-1741.102961.

Infrasound and low frequency noise from wind turbines: exposure and health effects – Bolin et al. (2011) “Wind turbines emit low frequency noise (LFN) and large turbines generally generate more LFN than small turbines. The dominant source of LFN is the interaction between incoming turbulence and the blades. Measurements suggest that indoor levels of LFN in dwellings typically are within recommended guideline values, provided that the outdoor level does not exceed corresponding guidelines for facade exposure. Three cross-sectional questionnaire studies show that annoyance from wind turbine noise is related to the immission level, but several explanations other than low frequency noise are probable. A statistically significant association between noise levels and self-reported sleep disturbance was found in two of the three studies. It has been suggested that LFN from wind turbines causes other, and more serious, health problems, but empirical support for these claims is lacking.” Karl Bolin et al 2011 Environ. Res. Lett. 6 035103 doi:10.1088/1748-9326/6/3/035103. [FULL TEXT]

Health effects and wind turbines: A review of the literature – Knopper & Ollson (2011) “Background: Wind power has been harnessed as a source of power around the world. Debate is ongoing with respect to the relationship between reported health effects and wind turbines, specifically in terms of audible and inaudible noise. As a result, minimum setback distances have been established world-wide to reduce or avoid potential complaints from, or potential effects to, people living in proximity to wind turbines. People interested in this debate turn to two sources of information to make informed decisions: scientific peer-reviewed studies published in scientific journals and the popular literature and internet. Methods: The purpose of this paper is to review the peer-reviewed scientific literature, government agency reports, and the most prominent information found in the popular literature. Combinations of key words were entered into the Thomson Reuters Web of KnowledgeSM and the internet search engine Google. The review was conducted in the spirit of the evaluation process outlined in the Cochrane Handbook for Systematic Reviews of Interventions. Results: Conclusions of the peer reviewed literature differ in some ways from those in the popular literature. In peer reviewed studies, wind turbine annoyance has been statistically associated with wind turbine noise, but found to be more strongly related to visual impact, attitude to wind turbines and sensitivity to noise. To date, no peer reviewed articles demonstrate a direct causal link between people living in proximity to modern wind turbines, the noise they emit and resulting physiological health effects. If anything, reported health effects are likely attributed to a number of environmental stressors that result in an annoyed/stressed state in a segment of the population. In the popular literature, self-reported health outcomes are related to distance from turbines and the claim is made that infrasound is the causative factor for the reported effects, even though sound pressure levels are not measured. Conclusions: What both types of studies have in common is the conclusion that wind turbines can be a source of annoyance for some people. The difference between both types is the reason for annoyance. While it is acknowledged that noise from wind turbines can be annoying to some and associated with some reported health effects (e.g., sleep disturbance), especially when found at sound pressure levels greater than 40 db(A), given that annoyance appears to be more strongly related to visual cues and attitude than to noise itself, self reported health effects of people living near wind turbines are more likely attributed to physical manifestation from an annoyed state than from wind turbines themselves. In other words, it appears that it is the change in the environment that is associated with reported health effects and not a turbine-specific variable like audible noise or infrasound. Regardless of its cause, a certain level of annoyance in a population can be expected (as with any number of projects that change the local environment) and the acceptable level is a policy decision to be made by elected officials and their government representatives where the benefits of wind power are weighted against their cons. Assessing the effects of wind turbines on human health is an emerging field and conducting further research into the effects of wind turbines (and environmental changes) on human health, emotional and physical, is warranted.” Loren D Knopper and Christopher A Ollson, Environmental Health 2011, 10:78 doi:10.1186/1476-069X-10-78. [FULL TEXT]

Evaluating the impact of wind turbine noise on health-related quality of life – Shepherd et al. (2011) “We report a cross-sectional study comparing the health-related quality of life (HRQOL) of individuals residing in the proximity of a wind farm to those residing in a demographically matched area sufficiently displaced from wind turbines. The study employed a nonequivalent comparison group posttest-only design. Self-administered questionnaires, which included the brief version of the World Health Organization quality of life scale, were delivered to residents in two adjacent areas in semirural New Zealand. Participants were also asked to identify annoying noises, indicate their degree of noise sensitivity, and rate amenity. Statistically significant differences were noted in some HRQOL domain scores, with residents living within 2 km of a turbine installation reporting lower overall quality of life, physical quality of life, and environmental quality of life. Those exposed to turbine noise also reported significantly lower sleep quality, and rated their environment as less restful. Our data suggest that wind farm noise can negatively impact facets of HRQOL.” Daniel Shepherd, David McBride, David Welch, Kim N Dirks, Erin M Hill, Noise & Health, 2011, 13, 54, 333-339, DOI: 10.4103/1463-1741.85502. [FULL TEXT]

Low-frequency noise from large wind turbines – Møller & Pedersen (2011) “As wind turbines get larger, worries have emerged that the turbine noise would move down in frequency and that the low-frequency noise would cause annoyance for the neighbors. The noise emission from 48 wind turbines with nominal electric power up to 3.6 MW is analyzed and discussed. The relative amount of low-frequency noise is higher for large turbines (2.3–3.6 MW) than for small turbines (≤ 2 MW), and the difference is statistically significant. The difference can also be expressed as a downward shift of the spectrum of approximately one-third of an octave. A further shift of similar size is suggested for future turbines in the 10-MW range. Due to the air absorption, the higher low-frequency content becomes even more pronounced, when sound pressure levels in relevant neighbor distances are considered. Even when A-weighted levels are considered, a substantial part of the noise is at low frequencies, and for several of the investigated large turbines, the one-third-octave band with the highest level is at or below 250 Hz. It is thus beyond any doubt that the low-frequency part of the spectrum plays an important role in the noise at the neighbors.” Henrik Møller and Christian Sejer Pedersen, J. Acoust. Soc. Am. Volume 129, Issue 6, pp. 3727-3744, http://dx.doi.org/10.1121/1.3543957. [FULL TEXT]

Wind Turbine Noise – Harrison (2011) “Following an introduction to noise and noise regulation of wind turbines, the problem of adverse health effects of turbine noise is discussed. This is attributed to the characteristics of turbine noise and deficiencies in the regulation of this noise. Both onshore and offshore wind farms are discussed.” John P. Harrison, Bulletin of Science Technology Society August 2011 vol. 31 no. 4 256-261, doi: 10.1177/0270467611412549. [FULL TEXT]

The Problems With “Noise Numbers” for Wind Farm Noise Assessment – Thorne (2011) “Human perception responds primarily to sound character rather than sound level. Wind farms are unique sound sources and exhibit special audible and inaudible characteristics that can be described as modulating sound or as a tonal complex. Wind farm compliance measures based on a specified noise number alone will fail to address problems with noise nuisance. The character of wind farm sound, noise emissions from wind farms, noise prediction at residences, and systemic failures in assessment processes are examined. Human perception of wind farm sound is compared with noise assessment measures and complaint histories. The adverse effects on health of persons susceptible to noise from wind farms are examined and a hypothesis, the concept of heightened noise zones (pressure variations), as a marker for cause and effect is advanced. A sound level of LAeq 32 dB outside a residence and above an individual’s threshold of hearing inside the home are identified as markers for serious adverse health effects affecting susceptible individuals. The article is referenced to the author’s research, measurements, and observations at different wind farms in New Zealand and Victoria, Australia.” Bob Thorne, Bulletin of Science Technology Society August 2011 vol. 31 no. 4 262-290, doi: 10.1177/0270467611412557.

The Noise From Wind Turbines: Potential Adverse Impacts on Children’s Well-Being – Bronzaft (2011) “Research linking loud sounds to hearing loss in youngsters is now widespread, resulting in the issuance of warnings to protect children’s hearing. However, studies attesting to the adverse effects of intrusive sounds and noise on children’s overall mental and physical health and well-being have not received similar attention.This, despite the fact that many studies have demonstrated that intrusive noises such as those from passing road traffic, nearby rail systems, and overhead aircraft can adversely affect children’s cardiovascular system, memory, language development, and learning acquisition. While some schools in the United States have received funds to abate intrusive aircraft noise, for example, many schools still expose children to noises from passing traffic and overhead aircraft. Discussion focuses on the harmful effects of noise on children, what has to be done to remedy the situation, and the need for action to lessen the impacts of noise from all sources. Furthermore, based on our knowledge of the harmful effects of noise on children’s health and the growing body of evidence to suggest the potential harmful effects of industrial wind turbine noise, it is strongly urged that further studies be conducted on the impacts of industrial wind turbines on their health, as well as the health of their parents, before forging ahead in siting industrial wind turbines.” Arline L. Bronzaft, Bulletin of Science Technology Society August 2011 vol. 31 no. 4 291-295, doi: 10.1177/0270467611412548. [FULL TEXT]

Infrasound From Wind Turbines Could Affect Humans – Salt & Kaltenbach (2011) “Wind turbines generate low-frequency sounds that affect the ear. The ear is superficially similar to a microphone, converting mechanical sound waves into electrical signals, but does this by complex physiologic processes. Serious misconceptions about low-frequency sound and the ear have resulted from a failure to consider in detail how the ear works. Although the cells that provide hearing are insensitive to infrasound, other sensory cells in the ear are much more sensitive, which can be demonstrated by electrical recordings. Responses to infrasound reach the brain through pathways that do not involve conscious hearing but instead may produce sensations of fullness, pressure or tinnitus, or have no sensation. Activation of subconscious pathways by infrasound could disturb sleep. Based on our current knowledge of how the ear works, it is quite possible that low-frequency sounds at the levels generated by wind turbines could affect those living nearby.” Alec N. Salt, James A. Kaltenbach, Bulletin of Science Technology Society August 2011 vol. 31 no. 4 296-302, doi: 10.1177/0270467611412555.

Properly Interpreting the Epidemiologic Evidence About the Health Effects of Industrial Wind Turbines on Nearby Residents – Phillips (2011) “There is overwhelming evidence that wind turbines cause serious health problems in nearby residents, usually stress-disorder-type diseases, at a nontrivial rate. The bulk of the evidence takes the form of thousands of adverse event reports. There is also a small amount of systematically gathered data. The adverse event reports provide compelling evidence of the seriousness of the problems and of causation in this case because of their volume, the ease of observing exposure and outcome incidence, and case-crossover data. Proponents of turbines have sought to deny these problems by making a collection of contradictory claims including that the evidence does not “count,” the outcomes are not “real” diseases, the outcomes are the victims’ own fault, and that acoustical models cannot explain why there are health problems so the problems must not exist. These claims appeared to have swayed many nonexpert observers, though they are easily debunked. Moreover, though the failure of models to explain the observed problems does not deny the problems, it does mean that we do not know what, other than kilometers of distance, could sufficiently mitigate the effects. There has been no policy analysis that justifies imposing these effects on local residents. The attempts to deny the evidence cannot be seen as honest scientific disagreement and represent either gross incompetence or intentional bias.” Carl V. Phillips, Bulletin of Science Technology Society August 2011 vol. 31 no. 4 303-315, doi: 10.1177/0270467611412554. [FULL TEXT]

Toward a Case Definition of Adverse Health Effects in the Environs of Industrial Wind Turbines: Facilitating a Clinical Diagnosis – McMurtry (2011) “Internationally, there are reports of adverse health effects (AHE) in the environs of industrial wind turbines (IWT). There was multidisciplinary confirmation of the key characteristics of the AHE at the first international symposium on AHE/IWT. The symptoms being reported are consistent internationally and are characterized by crossover findings or a predictable appearance of signs and symptoms present with exposure to IWT sound energy and amelioration when the exposure ceases. There is also a revealed preference of victims to seek restoration away from their homes. This article identifies the need to create a case definition to establish a clinical diagnosis. A case definition is proposed that identifies the sine qua non diagnostic criteria for a diagnosis of adverse health effects in the environs of industrial wind turbines. Possible, probable, and confirmed diagnoses are detailed. The goal is to foster the adoption of a common case definition that will facilitate future research efforts.” Robert Y. McMurtry, Bulletin of Science Technology Society August 2011 vol. 31 no. 4 316-320, doi: 10.1177/0270467611415075. [FULL TEXT]

Industrial Wind Turbine Development and Loss of Social Justice? – Krogh (2011) “This article explores the loss of social justice reported by individuals living in the environs of industrial wind turbines (IWTs). References indicate that some individuals residing in proximity to IWT facilities experience adverse health effects. These adverse health effects are severe enough that some families have abandoned their homes. Individuals report they welcomed IWTs into their community and the negative consequences were unexpected. Expressions of grief are exacerbated by the emotional and physical toll of individuals’ symptoms, loss of enjoyment of homes and property, disturbed living conditions, financial loss, and the lack of society’s recognition of their situation. The author has investigated the reported loss of social justice through a review of literature, personal interviews with, and communications from, those reporting adverse health effects. The author’s intention is to create awareness that loss of social justice is being associated with IWT development. This loss of justice arises from a number of factors, including the lack of fair process, the loss of rights, and associated disempowerment. These societal themes require further investigation. Research by health professionals and social scientists is urgently needed to address the health and social impacts of IWTs operating near family homes.” Carmen M. E. Krogh, Bulletin of Science Technology Society August 2011 vol. 31 no. 4 321-333, doi: 10.1177/0270467611412550.

WindVOiCe, a Self-Reporting Survey: Adverse Health Effects, Industrial Wind Turbines, and the Need for Vigilance Monitoring – Krogh et al. (2011) “Industrial wind turbines have been operating in many parts of the globe. Anecdotal reports of perceived adverse health effects relating to industrial wind turbines have been published in the media and on the Internet. Based on these reports, indications were that some residents perceived they were experiencing adverse health effects. The purpose of the WindVOiCe health survey was to provide vigilance monitoring for those wishing to report their perceived adverse health effects. This article discusses the results of a self reporting health survey regarding perceived adverse health effects associated with industrial wind turbines.” Carmen M.E. Krogh, Lorrie Gillis, Nicholas Kouwen, Jeff Aramini, Bulletin of Science Technology Society August 2011 vol. 31 no. 4 334-345, doi: 10.1177/0270467611412551.

Can road traffic mask sound from wind turbines? Response to wind turbine sound at different levels of road traffic sound – Pedersen et al. (2010) “Wind turbines are favoured in the switch-over to renewable energy. Suitable sites for further developments could be difficult to find as the sound emitted from the rotor blades calls for a sufficient distance to residents to avoid negative effects. The aim of this study was to explore if road traffic sound could mask wind turbine sound or, in contrast, increases annoyance due to wind turbine noise. Annoyance of road traffic and wind turbine noise was measured in the WINDFARMperception survey in the Netherlands in 2007 (n=725) and related to calculated levels of sound. The presence of road traffic sound did not in general decrease annoyance with wind turbine noise, except when levels of wind turbine sound were moderate (35–40 dB(A) Lden) and road traffic sound level exceeded that level with at least 20 dB(A). Annoyance with both noises was intercorrelated but this correlation was probably due to the influence of individual factors. Furthermore, visibility and attitude towards wind turbines were significantly related to noise annoyance of modern wind turbines. The results can be used for the selection of suitable sites, possibly favouring already noise exposed areas if wind turbine sound levels are sufficiently low.” Eja Pedersen, Frits van den Berg, Roel Bakker, Jelte Bouma, Energy Policy, Volume 38, Issue 5, May 2010, Pages 2520–2527, http://dx.doi.org/10.1016/j.enpol.2010.01.001. [FULL TEXT]

Response to noise from modern wind farms in The Netherlands – Pedersen et al. (2009) “The increasing number and size of wind farms call for more data on human response to wind turbine noise, so that a generalized dose-response relationship can be modeled and possible adverse health effects avoided. This paper reports the results of a 2007 field study in The Netherlands with 725 respondents. A dose-response relationship between calculated A-weighted sound pressure levels and reported perception and annoyance was found. Wind turbine noise was more annoying than transportation noise or industrial noise at comparable levels, possibly due to specific sound properties such as a “swishing” quality, temporal variability, and lack of nighttime abatement. High turbine visibility enhances negative response, and having wind turbines visible from the dwelling significantly increased the risk of annoyance. Annoyance was strongly correlated with a negative attitude toward the visual impact of wind turbines on the landscape. The study further demonstrates that people who benefit economically from wind turbines have a significantly decreased risk of annoyance, despite exposure to similar sound levels. Response to wind turbine noise was similar to that found in Sweden so the dose-response relationship should be generalizable.” Eja Pedersen, Frits van den Berg, Roel Bakker, and Jelte Bouma, J. Acoust. Soc. Am. Volume 126, Issue 2, pp. 634-643 (2009), DOI: http://dx.doi.org/10.1121/1.3160293. [FULL TEXT]

The impact of visual factors on noise annoyance among people living in the vicinity of wind turbines – Pedersen & Larsman (2008) “Wind turbines are highly visible objects and the response to wind turbine noise is possibly influenced by visual factors. In this study, visibility of the noise source, visual attitude and vertical visual angle (VVA) in different landscapes were explored. Data from two cross-sectional field studies carried out among people living near wind turbines (n=1095) were used for structural equation modelling. A proposed model of the influence of visual attitude on noise annoyance, also comprising the influence of noise level and general attitude, was tested among respondents who could see vs. respondents who could not see wind turbines from their homes, living in flat vs. hilly/rocky terrain, and living in built-up vs. rural areas. Visual attitude towards the noise source was associated with noise annoyance to different degrees in different situations. A negative visual attitude, more than multi-modal effects between auditory and visual stimulation, enhanced the risk for noise annoyance and possibly also prevented psychophysiological restoration possibilities. Aesthetic evaluations of the noise source should be taken into account when exploring response to environmental noise.” Eja Pedersen, Pernilla Larsman, Journal of Environmental Psychology, Volume 28, Issue 4, December 2008, Pages 379–389, http://dx.doi.org/10.1016/j.jenvp.2008.02.009.

Experimental study to determine wind-induced noise and windscreen attenuation effects on microphone response for environmental wind turbine and other applications – Hessler et al. (2008) “Despite the use of windscreens, the measurement of ambient sound levels or noise emissions in quiet environments can be adversely affected by wind blowing over the microphone. This is especially true when environmental impact assessments are being carried out for proposed wind turbine power projects – where the objective is to determine the level of background masking noise available as a function of wind speed, since any potential noise impact from the project will only occur under moderately windy conditions. Under calm conditions the project will produce no noise at all. A number of windscreen products are commercially available for short and long-term sound level monitoring in adverse weather conditions. Generally, these windscreens vary by physical size and the method of preventing water from reaching the microphone. High frequency attenuation effects are usually available from the product suppliers but, in general, low frequency turbulence effects are not available. Consequently, a controlled laboratory test program was carried out in a state-of-the-art wind tunnel at the Fraunhofer Institut fu¨r Bauphysik in Stuttgart, Germany to quantify the level of low frequency interference (down to 6.3 Hz) associated with a number of different foam windscreens and an aerodynamic microphone nose cone. A total of nine configurations were tested with “quiet“ airflow only, artificial noise only and noise plus airflow to evaluate both low frequency wind induced noise and high frequency attenuation effects. The test program demonstrated that the largest size foam-based windscreens provided the most protection from flow induced noise due to wind. Flow induced noise by air flow alone was estimated from the study results and compared to community noise measurements at a typical wind turbine site. It was determined that flow induced wind noise does not have a significant or detrimental effect on the measurement of A-weighted sound levels under wind conditions of concern as long as the suggested measurement techniques described herein are followed.” Hessler, George F.; Hessler, David M.; Brandsta¨tt, Peter; Bay, Karlheinz, Noise Control Engineering Journal, Volume 56, Number 4, 1 July 2008 , pp. 300-309(10), DOI: http://dx.doi.org/10.3397/1.2949926.

Wind turbine noise, annoyance and self-reported health and well-being in different living environments – Pedersen & Waye (2007) “Objectives: To evaluate the prevalence of perception and annoyance due to wind turbine noise among people living near the turbines, and to study relations between noise and perception/annoyance, with focus on differences between living environments. Methods: A cross-sectional study was carried out in seven areas in Sweden across dissimilar terrain and different degrees of urbanisation. A postal questionnaire regarding living conditions including response to wind turbine noise was completed by 754 subjects. Outdoor A-weighted sound pressure levels (SPLs) were calculated for each respondent. Perception and annoyance due to wind turbine noise in relation to SPLs was analysed with regard to dissimilarities between the areas. Results: The odds of perceiving wind turbine noise increased with increasing SPL (OR 1.3; 95% CI 1.25 to 1.40). The odds of being annoyed by wind turbine noise also increased with increasing SPLs (OR 1.1; 95% CI 1.01 to 1.25). Perception and annoyance were associated with terrain and urbanisation: (1) a rural area increased the risk of perception and annoyance in comparison with a suburban area; and (2) in a rural setting, complex ground (hilly or rocky terrain) increased the risk compared with flat ground. Annoyance was associated with both objective and subjective factors of wind turbine visibility, and was further associated with lowered sleep quality and negative emotions. Conclusion: There is a need to take the unique environment into account when planning a new wind farm so that adverse health effects are avoided. The influence of area-related factors should also be considered in future community noise research.” Eja Pedersen, Kerstin Persson Waye, Occup Environ Med 2007;64:480-486, doi:10.1136/oem.2006.031039. [FULL TEXT]

Living in the Vicinity of Wind Turbines — A Grounded Theory Study – Pedersen et al. (2007) “Little is known of wind turbines’ impact on people living in their vicinity. The aim of this study was to gain a deeper understanding of how people perceive and are affected by wind turbines in their living environment. In-depth interviews with 15 informants, strategically chosen to form a heterogeneous group, were analyzed using the constant comparative method of grounded theory. The informants were to different extents affected by the swishing noise, flickering light, and constant movement of the turbines’ rotor blades. Some informants perceived the exposures as outside their territory while others perceived them as intrusion into privacy; a divergence partly determined by the informants’ personal values about the living environment. The feeling of intrusion was associated with feeling a lack of control, subjected to injustice, a lack of influence, and not being believed. Informants used various coping strategies, such as rebuilding their houses or complaining, but mainly tried to ignore exposures from the wind turbines. The findings can help us to better understand the severe reactions wind turbines sometimes evoke and contribute to the knowledge base used when planning for new wind farms.” E. Pedersen, LR-M. Hallberg & K.P. Waye, Qualitative Research in Psychology, Volume 4, Issue 1-2, 2007, DOI:10.1080/14780880701473409.

Perception of low-frequency acoustic signals by a harbour porpoise (Phocoena phocoena) in the presence of simulated offshore wind turbine noise – Lucke et al. (2007) “Using auditory evoked potential (AEP) methods, a study was conducted on a harbour porpoise (Phocoena phocoena) at the Dolfinarium Harderwijk in The Netherlands. The study measured the audible range of wind turbine sounds and their potential masking effects on the acoustic perception of the animal. AEPs were evoked with two types of acoustic stimuli: (1) click-type signals and (2) amplitude-modulated signals. The masking noise resembling the underwater sound emissions of an operational wind turbine was simulated. At first, the animal’s hearing threshold was measured at frequencies between 0.7 and 16 kHz. Subsequently, these measurements were repeated at frequencies between 0.7 and 2.8 kHz in the presence of two different levels of masking noise. The resulting data show a masking effect of the simulated wind turbine sound at 128 dB re 1 μPa at 0.7, 1.0, and 2.0 kHz. This masking effect varied between 4.8 and 7.3 dB at those frequencies. No significant masking was measured at a masking level of 115 dB re 1 μPa. The available data indicate that the potential masking effect would be limited to short ranges in the open sea, but limitations exist to this conclusion and all estimates are based on existing turbine types, not taking into account future developments of larger and potentially noisier turbine types.” Lucke, Klaus, Lepper, Paul A., Hoeve, Bert, Everaarts, Eligius, van Elk, Niels, Siebert, Ursula, Aquatic Mammals, 33 (1), pp. 55-68, DOI 10.1578/AM.33.1.2007.55. [FULL TEXT]

Location and quantification of noise sources on a wind turbine – Oerlemans et al. (2007) “Acoustic field measurements were carried out on a three-bladed wind turbine with a rotor diameter of 58 m, in order to characterize the noise sources and to verify whether trailing edge noise from the blades was dominant. To assess the effect of blade roughness, one blade was cleaned, one blade was tripped, and one blade remained untreated. A large horizontal microphone array, positioned about one rotor diameter upwind from the turbine, was used to measure the distribution of the noise sources in the rotor plane and on the individual blades. The operation parameters of the turbine were recorded in parallel to the acoustic tests. In total more than 100 measurements were performed at wind speeds between 6 and 10 m/s. The array results reveal that besides a minor source at the rotor hub, practically all noise (emitted to the ground) is produced during the downward movement of the blades. This strongly asymmetric source pattern can be explained by convective amplification and trailing edge noise directivity. The blade noise is produced at the outer part of the blades (but not at the very tip), and the level scales with the fifth power of the local flow speed. Comparison of the noise from the individual blades shows that the tripped blade is significantly noisier than the other two. Narrowband analysis of the de-dopplerized blade noise spectra indicates that trailing edge bluntness noise is not important. All in all, the test results convincingly show that broadband trailing edge noise is the dominant noise source for this wind turbine.” S. Oerlemans, P. Sijtsma, B. Méndez López, Journal of Sound and Vibration, Volume 299, Issues 4–5, 6 February 2007, Pages 869–883, http://dx.doi.org/10.1016/j.jsv.2006.07.032.

Wind turbine underwater noise and marine mammals: implications of current knowledge and data needs – Madsen et al. (2006) “The demand for renewable energy has led to construction of offshore wind farms with high-power turbines, and many more wind farms are being planned for the shallow waters of the world’s marine habitats. The growth of offshore wind farms has raised concerns about their impact on the marine environment. Marine mammals use sound for foraging, orientation and communication and are therefore possibly susceptible to negative effects of man-made noise generated from constructing and operating large offshore wind turbines. This paper reviews the existing literature and assesses zones of impact from different noise-generating activities in conjunction with wind farms on 4 representative shallow-water species of marine mammals. Construction involves many types of activities that can generate high sound pressure levels, and pile-driving seems to be the noisiest of all. Both the literature and modeling show that pile-driving and other activities that generate intense impulses during construction are likely to disrupt the behavior of marine mammals at ranges of many kilometers, and that these activities have the potential to induce hearing impairment at close range. The reported noise levels from operating wind turbines are low, and are unlikely to impair hearing in marine mammals. The impact zones for marine mammals from operating wind turbines depend on the low-frequency hearing-abilities of the species in question, on sound-propagation conditions, and on the presence of other noise sources such as shipping. The noise impact on marine mammals is more severe during the construction of wind farms than during their operation.” P. T. Madsen, M. Wahlberg, J. Tougaard, K. Lucke, P. Tyack, Marine Ecology Progress Series, 309:279-295 (2006), doi:10.3354/meps309279. [FULL TEXT]

Infrasound Emission from Wind Turbines – Jakobsen (2005) “A critical survey of all known published measurement results of infrasound from wind turbines has been made. The survey indicates that wind turbines of contemporary design with an upwind rotor generate very faint infrasound with a level far below the threshold of perception even at a rather short distance. From considerations on propagation and transmission of infrasound it is concluded that infrasound from such upwind turbines can be neglected when evaluating the environment effects of wind turbines. Turbines with downwind rotors produce 10 – 30 dB higher infrasound levels, and these may exceed relevant assessment criteria for dwellings in the immediate neighbourhood. When longer distances are considered, neither downwind nor upwind turbines are capable of violating assessment criteria for infrasound. This paper considers whether other aspects of the noise than the infrasound can explain the indicated adverse public reactions to large downwind turbines.” Jørgen Jakobsen, Low Frequency Noise, Vibration and Active Control, Volume 24, Number 3 / September 2005, DOI: 10.1260/026309205775374451. [FULL TEXT]

Perception and annoyance due to wind turbine noise—a dose–response relationship – Pedersen & Waye (2004) “Installed global wind power increased by 26% during 2003, with U.S and Europe accounting for 90% of the cumulative capacity. Little is known about wind turbines’ impact on people living in their vicinity. The aims of this study were to evaluate the prevalence of annoyance due to wind turbine noise and to study dose–response relationships. Interrelationships between noise annoyance and sound characteristics, as well as the influence of subjective variables such as attitude and noise sensitivity, were also assessed. A cross-sectional study was performed in Sweden in 2000. Responses were obtained through questionnaires (n = 351; response rate 68.4%), and doses were calculated as A-weighted sound pressure levels for each respondent. A statistically significant dose–response relationship was found, showing higher proportion of people reporting perception and annoyance than expected from the present dose–response relationships for transportation noise. The unexpected high proportion of annoyance could be due to visual interference, influencing noise annoyance, as well as the presence of intrusive sound characteristics. The respondents’ attitude to the visual impact of wind turbines on the landscape scenery was found to influence noise annoyance.” Eja Pedersen and Kerstin Persson Waye, J. Acoust. Soc. Am. Volume 116, Issue 6, pp. 3460-3470, http://dx.doi.org/10.1121/1.1815091. [FULL TEXT]

Effects of the wind profile at night on wind turbine sound – van den Berg (2004) “Since the start of the operation of a 30 MW, 17 turbine wind park, residents living 500 m and more from the park have reacted strongly to the noise; residents up to 1900 m distance expressed annoyance. To assess actual sound immission, long term measurements (a total of over 400 night hours in 4 months) have been performed at 400 and 1500 m from the park. In the original sound assessment a fixed relation between wind speed at reference height (10 m) and hub height (98 m) had been used. However, measurements show that the wind speed at hub height at night is up to 2.6 times higher than expected, causing a higher rotational speed of the wind turbines and consequentially up to 15 dB higher sound levels, relative to the same reference wind speed in daytime. Moreover, especially at high rotational speeds the turbines produce a ‘thumping’, impulsive sound, increasing annoyance further. It is concluded that prediction of noise immission at night from (tall) wind turbines is underestimated when measurement data are used (implicitly) assuming a wind profile valid in daytime.” G.P. van den Berg, Journal of Sound and Vibration, Volume 277, Issues 4–5, 5 November 2004, Pages 955–970, http://dx.doi.org/10.1016/j.jsv.2003.09.050.

Psycho-acoustic characters of relevance for annoyance of wind turbine noise – Waye & Öhrström (2002) “The knowledge of annoyance and perception of wind turbine noise is limited, although some previous studies have found that the relationship between the equivalent noise level and annoyance was weak. The hypothesis for this study was that different sound characters in the noise not fully described by the equivalent noise level, are of importance for annoyance and noise perception. In total, 25 subjects were exposed to five different wind turbine noises at the level of 40 dBL_Aeq. Subjective ratings of annoyance, relative annoyance and for how long they were aware of the noises were carried out after 10 min exposures. This was followed by 3 min exposures where perception and annoyance of 14 psycho-acoustic descriptors were evaluated. The results showed that the rating of annoyance, relative annoyance and awareness was different between the wind turbine noises, although they had the same equivalent noise level. A psycho-acoustic profile was obtained for each noise, which subjectively described the most and the least annoying sound parameters. None of the psycho-acoustic parameters, sharpness, loudness, roughness, fluctuation strength or modulation could explain the differences in annoyance response.” K.Persson Waye, E. Öhrström, Journal of Sound and Vibration, Volume 250, Issue 1, 7 February 2002, Pages 65–73, http://dx.doi.org/10.1006/jsvi.2001.3905.

Aeroacoustics of large wind turbines – Hubbard & Shepherd (1991) “This paper reviews published information on aerodynamically generated noise from large horizontal axis wind turbines operated for electric power generation. Methods are presented for predicting both the discrete frequency rotational noise components and the broadband noise components, and results are compared with measurements. Refraction effects that result in the formation of high-frequency shadow zones in the upwind direction and channeling effects for the low frequencies in the downwind direction are illustrated. Special topics such as distributed source effects in prediction and the role of building dynamics in perception are also included. © 1991 Acoustical Society of America.” Harvey H. Hubbard and Kevin P. Shepherd, J. Acoust. Soc. Am. Volume 89, Issue 6, pp. 2495-2508 (1991), http://dx.doi.org/10.1121/1.401021.

Noise characteristics of large wind turbine generators – Hubbard et al. (1983) “Data on wind turbine noise taken from the large wind turbines, the Mod-OA, Mod-1, and Mod-2, are examined for guides to developing a predictive model for wind turbine noise. Data were taken on the pressure time histories, the narrowband spectra, the one-third octave band spectra, and the overall linear and A-weighted noise levels. A thumping noise recorded upstream from the Mod-1 was due to the encounter of the downwind turning blades with the tower wake. The upwind Mod-2 caused broadband noise with peaks at 800 Hz, caused by interactions of turbulent boundary layers with the blade trailing edges. Amplitude modulation of the overall pressure time history was associated with a periodic swishing noise. Some noises were machine specific; however, the low frequency loading was directed upwind and downwind from the rotors in all machines, while the broadband noise was nondirectional. The wind velocity gradient elongated the noise downwind and shortened it upwind. Wake acoustic measurements of two of the Mod-2 machines indicated that the wake does not affect the acoustic output of one Mod-2 downwind from the other. Finally, evidence was found for random phase adding of broadband noise five rotors downstream.” Hubbard, H H, Grosveld, F W, Shepherd, K P, Noise Control Engineering Journal (ISSN 0736-2501), vol. 21, July-Aug. 1983, p. 21-29.