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Resource Documents: Impacts (117 items)


Also see NWW "costs/benefits" FAQ

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.

Date added:  April 8, 2016
NoisePrint storyE-mail story

Journal of the Acoustical Society of America: Special issue on wind turbine noise

Author:  Various

Effect of modulation depth, frequency, and intermittence on wind turbine noise annoyance
Christina Ioannidou, Sébastien Santurette and Cheol-Ho Jeong
J. Acoust. Soc. Am. 139, 1241 (2016);

Amplitude modulation (AM) may be an important factor for the perceived annoyance of wind turbine noise (WTN). Two AM types, typically referred to as “normal AM” (NAM) and “other AM” (OAM), characterize WTN AM, OAM corresponding to having intermittent periods with larger AM depth in lower frequency regions than NAM. The extent to which AM depth, frequency, and type affect WTN annoyance remains uncertain. Moreover, the temporal variations of WTN AM have often not been considered. Here, realistic stimuli accounting for such temporal variations were synthesized such that AM depth, frequency, and type, while determined from real on-site recordings, could be varied systematically. Listening tests with both original and synthesized stimuli showed that a reduction in mean AM depth across the spectrum led to a significant decrease in annoyance. When the spectrotemporal characteristics of the original far-field stimuli and the temporal AM variations were taken into account, the effect of AM frequency remained limited and the presence of intermittent OAM periods did not affect annoyance. These findings suggest that, at a given overall level, the AM depth of NAM periods is the most crucial AM parameter for WTN annoyance.

Introductory remarks for special issue on wind turbine noise
Paul Schomer and Sanford Fidell
J. Acoust. Soc. Am. 139, 1430 (2016);

The effects of wind turbine noise (WTN) on residential populations have become a matter of considerable popular and technical controversy in recent years. Because fewer resources have been devoted to scientific study of WTN effects than to other forms of environmental noise, much speculation and debate still surrounds the origins and nature of effects of WTN.

This special issue presents findings of a thorough cross-sectional field study of community response to wind turbines conducted by Health Canada. The reported study is notable for its scale, design, care in execution, and sophistication of analysis. It assesses both subjective and objective end points, and it identifies limits to the generalizability of reported findings. Substantial quantities of supplementary data, which accompany the articles, may be accessed electronically through the ASA website. The URLs for this material may be found in the individual articles.

As noted by the authors, interpretations of study findings are subject to limitations inherent to the design itself. Most notably, cross-sectional studies cannot establish causal relationships, nor can the Health Canada study be used to make inferences about the presence of health effects that may occur at very low prevalence rates. The current findings cannot be generalized to settings in which A-weighted WTN levels exceed 46 dB, the upper limit of WTN exposure investigated. The study likewise offers no insight about long term changes in community reaction to WTN beyond the observation that suggests annoyance with WTN does not appear to level off or subside after a year of exposure.

Beyond annoyance, the Health Canada study indirectly suggests that if health effects do exist, they would occur at very low prevalence rates, and that future work in this area could benefit from carefully executed case-control studies in addition to longitudinal studies. Case-control studies would provide an opportunity to study WTN impacts from areas with very low population densities. This is not possible in large-scale cross-sectional studies that aim to assess impacts on a larger population.

A rather strong finding to emerge from this study is that there appears to be a sharp break point at 35 dB where the odds of reporting high annoyance with WTN increase by a factor of 10, and continue to increase further at the highest WTN level category assessed.

This finding lends support to a criterion of meaningful WTN effect at about 35 dB. Such a criterion would be based on the level at which attitudes change, rather than a sleep based limit. The community tolerance level (CTL), analyzed as a part of the paper that models annoyance, provides a good way to compare WTN annoyance to the annoyance caused by more common community noises, such as road traffic. The authors show the close correspondence between the present study and four earlier European studies, lending further support to the use of CTL for comparative analyses

The study further shows that the noise emitted by wind turbines is clearly not the only annoying feature attributed to wind turbines. Annoyance with wind turbines was also related to visual impacts, shadow flicker, and blinking lights. Participants were also found to be concerned for their physical safety. That concern, in turn, was related to annoyance. These findings imply that amelioration of community reactions to wind turbines should consider these factors collectively.

The noise metric that best predicts community response to WTN remains another open question. The Health Canada study examined both A- and C-weighted metrics, which were found to be highly correlated. This may mean only that the several models of wind turbines included in this study all have similar spectral characteristics. The high correlation does not mean that C-weighted assessments may be replaced by A-weighted analyses. Concerns about low frequency noise are best addressed by metrics that are most sensitive to low frequency exposures.

Although A-weighted noise metrics may correlate with community responses to wind turbine noise, this does not necessarily make them the preferred metrics for use in this application. Indeed, the statistical association between A-weighted WTN levels and annoyance in the Health Canada study was especially weak: the base model accounted for only about 9% of the variance when only WTN noise levels were considered. The strength of the model only increased to 58% after other “non-A-weighted” variables were added.

The Health Canada study has clearly advanced understanding of WTN effects, but much remains to be learned.

Wind turbine sound power measurements
Stephen E. Keith, Katya Feder, Sonia A. Voicescu, Victor Soukhovtsev, Allison Denning, Jason Tsang, Norm Broner, Werner Richarz and Frits van den Berg
J. Acoust. Soc. Am. 139, 1431 (2016);

This paper provides experimental validation of the sound power level data obtained from manufacturers for the ten wind turbine models examined in Health Canada’s Community Noise and Health Study (CNHS). Within measurement uncertainty, the wind turbine sound power levels measured using IEC 61400-11 [(2002). (International Electrotechnical Commission, Geneva)] were consistent with the sound power level data provided by manufacturers. Based on measurements, the sound power level data were also extended to 16 Hz for calculation of C-weighted levels. The C-weighted levels were 11.5 dB higher than the A-weighted levels (standard deviation 1.7 dB). The simple relationship between A- and C- weighted levels suggests that there is unlikely to be any statistically significant difference between analysis based on either C- or A-weighted data. [download PDF]

Wind turbine sound pressure level calculations at dwellings
Stephen E. Keith, Katya Feder, Sonia A. Voicescu, Victor Soukhovtsev, Allison Denning, Jason Tsang, Norm Broner, Tony Leroux, Werner Richarz and Frits van den Berg
J. Acoust. Soc. Am. 139, 1436 (2016);

This paper provides calculations of outdoor sound pressure levels (SPLs) at dwellings for 10 wind turbine models, to support Health Canada’s Community Noise and Health Study. Manufacturer supplied and measured wind turbine sound power levels were used to calculate outdoor SPL at 1238 dwellings using ISO [(1996). ISO 9613-2−Acoustics] and a Swedish noise propagation method. Both methods yielded statistically equivalent results. The A- and C-weighted results were highly correlated over the 1238 dwellings (Pearson’s linear correlation coefficient r > 0.8). Calculated wind turbine SPLs were compared to ambient SPLs from other sources, estimated using guidance documents from the United States and Alberta, Canada. [download PDF]

Exposure to wind turbine noise: Perceptual responses and reported health effects
David S. Michaud, Katya Feder, Stephen E. Keith, Sonia A. Voicescu, Leonora Marro, John Than, Mireille Guay, Allison Denning, D’Arcy McGuire, Tara Bower, Eric Lavigne, Brian J. Murray, Shelly K. Weiss and Frits van den Berg
J. Acoust. Soc. Am. 139, 1443 (2016);

Health Canada, in collaboration with Statistics Canada, and other external experts, conducted the Community Noise and Health Study to better understand the impacts of wind turbine noise (WTN) on health and well-being. A cross-sectional epidemiological study was carried out between May and September 2013 in southwestern Ontario and Prince Edward Island on 1238 randomly selected participants (606 males, 632 females) aged 18–79 years, living between 0.25 and 11.22 km from operational wind turbines. Calculated outdoor WTN levels at the dwelling reached 46 dBA. Response rate was 78.9% and did not significantly differ across sample strata. Self-reported health effects (e.g., migraines, tinnitus, dizziness, etc.), sleep disturbance, sleep disorders, quality of life, and perceived stress were not related to WTN levels. Visual and auditory perception of wind turbines as reported by respondents increased significantly with increasing WTN levels as did high annoyance toward several wind turbine features, including the following: noise, blinking lights, shadow flicker, visual impacts, and vibrations. Concern for physical safety and closing bedroom windows to reduce WTN during sleep also increased with increasing WTN levels. Other sample characteristics are discussed in relation to WTN levels. Beyond annoyance, results do not support an association between exposure to WTN up to 46 dBA and the evaluated health-related endpoints. [download PDF]

Personal and situational variables associated with wind turbine noise annoyance
David S. Michaud, Stephen E. Keith, Katya Feder, Sonia A. Voicescu, Leonora Marro, John Than, Mireille Guay, Tara Bower, Allison Denning, Eric Lavigne, Chantal Whelan, Sabine A. Janssen, Tony Leroux and Frits van den Berg
J. Acoust. Soc. Am. 139, 1455 (2016);

The possibility that wind turbine noise (WTN) affects human health remains controversial. The current analysis presents results related to WTN annoyance reported by randomly selected participants (606 males, 632 females), aged 18–79, living between 0.25 and 11.22 km from wind turbines. WTN levels reached 46 dB, and for each 5 dB increase in WTN levels, the odds of reporting to be either very or extremely (i.e., highly) annoyed increased by 2.60 [95% confidence interval: (1.92, 3.58), p < 0.0001]. Multiple regression models had R2’s up to 58%, with approximately 9% attributed to WTN level. Variables associated with WTN annoyance included, but were not limited to, other wind turbine-related annoyances, personal benefit, noise sensitivity, physical safety concerns, property ownership, and province. Annoyance was related to several reported measures of health and well-being, although these associations were statistically weak (R2 < 9%), independent of WTN levels, and not retained in multiple regression models. The role of community tolerance level as a complement and/or an alternative to multiple regression in predicting the prevalence of WTN annoyance is also provided. The analysis suggests that communities are between 11 and 26 dB less tolerant of WTN than of other transportation noise sources. [download PDF]

Self-reported and measured stress related responses associated with exposure to wind turbine noise
David S. Michaud, Katya Feder, Stephen E. Keith, Sonia A. Voicescu, Leonora Marro, John Than, Mireille Guay, Allison Denning, Tara Bower, Paul J. Villeneuve, Evan Russell, Gideon Koren and Frits van den Berg
J. Acoust. Soc. Am. 139, 1467 (2016);

The current study was the first to assess stress reactions associated with wind turbine noise (WTN) exposure using self-reported and objective measures. Randomly selected participants, aged 18–79 yr (606 males; 632 females), living between 0.25 and 11.22 km from wind turbines, were exposed to outdoor calculated WTN levels up to 46 dBA (response rate 78.9%). Multiple regression modeling left the great majority (77%–89%) of the variance in perceived stress scale (PSS) scores, hair cortisol concentrations, resting blood pressure, and heart rate unaccounted for, and WTN exposure had no apparent influence on any of these endpoints. PSS scores were positively, but weakly, related to cortisol concentrations and resting heart rate (Pearson r = 0.13 and r = 0.08, respectively). Across WTN categories, modeled mean PSS scores ranged from 13.15 to 13.84 (p = 0.8614). Modeled geometric means for hair cortisol concentrations, resting mean systolic, diastolic blood pressure, and heart rate were 150.54–191.12 ng/g (p = 0.5416), 113.38–116.82 mmHg (p = 0.4990), 67.98–70.34 mmHg (p = 0.5006), and 68.24–70.71 bpm (p = 0.5223), respectively. Irrespective of WTN levels, diastolic blood pressure appeared to be slightly (2.90 mmHg 95% CI: 0.75,5.05) higher among participants highly annoyed by blinking lights on turbines (p = 0.0081). Collectively, the findings do not support an association between exposure to WTN up to 46 dBA and elevated self-reported and objectively defined measures of stress. [download PDF]

Estimating annoyance to calculated wind turbine shadow flicker is improved when variables associated with wind turbine noise exposure are considered
Sonia A. Voicescu, David S. Michaud, Katya Feder, Leonora Marro, John Than, Mireille Guay, Allison Denning, Tara Bower, Frits van den Berg, Norm Broner and Eric Lavigne
J. Acoust. Soc. Am. 139, 1480 (2016);

The Community Noise and Health Study conducted by Health Canada included randomly selected participants aged 18–79 yrs (606 males, 632 females, response rate 78.9%), living between 0.25 and 11.22 km from operational wind turbines. Annoyance to wind turbine noise (WTN) and other features, including shadow flicker (SF) was assessed. The current analysis reports on the degree to which estimating high annoyance to wind turbine shadow flicker (HAWTSF) was improved when variables known to be related to WTN exposure were also considered. As SF exposure increased [calculated as maximum minutes per day (SFm)], HAWTSF increased from 3.8% at 0 ≤ SFm < 10 to 21.1% at SFm ≥ 30, p < 0.0001. For each unit increase in SFm the odds ratio was 2.02 [95% confidence interval: (1.68,2.43)]. Stepwise regression models for HAWTSF had a predictive strength of up to 53% with 10% attributed to SFm. Variables associated with HAWTSF included, but were not limited to, annoyance to other wind turbine-related features, concern for physical safety, and noise sensitivity. Reported dizziness was also retained in the final model at p = 0.0581. Study findings add to the growing science base in this area and may be helpful in identifying factors associated with community reactions to SF exposure from wind turbines. [download PDF]

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Date added:  April 7, 2016
Australia, Contracts, EconomicsPrint storyE-mail story

Neighbor participation agreement with the Moorabool Wind Farm

Author:  Moorabol Wind Farm, Westwind Energy

Thank you for meeting with us on Monday to talk about the Moorabool Wind Farm.

We value all feedback received in respect of the project from you, other neighbours to the project and many other members from the broader community. We have reflected on your concerns voiced in the meeting, and have considered how we can best support your intentions to sell your property if the wind farm is built.

As part of this process, we contacted a Ballarat real estate agent to discuss his opinion on the impact of the wind farm on neighbouring property values. The agent we spoke to has 17 years experience selling properties in your area as well as properties around the Waubra wind farm. He is fully aware of the perceived impact the wind farm may have on properties, and he indicated he has no recollection of a wind farm causing a property to be sold below market value. He did indicate that it could potentially take slightly longer for the property to sell depending on the turbine locations relative to the dwellings. We advised the dwelling on the property was greater than one kilometre from a proposed turbine site, and his opinion is there will be little if any impact to the sales process or price. He also indicated rural properties in the Ballan area are in high demand from Melbourne residents looking for a sea change, as well as Geelong and Ballarat residents looking to move closer to Melbourne. We are hopeful that this information can give you some comfort that your property is desirable, in an interesting location, and is likely to be sold at market value. We would be happy to share the agents contact details with you if you would like to discuss this further with him. We also discussed fees associated with the sales and marketing of a rural property, and the services available for consultation to prepare your house for the best possible sales outcome. The agent indicated that $4,000 in marketing fees will register your property on all the major internet sales sites and list advertisements in the local and Melbourne papers. He specified that guidance on improvements required to secure the most lucrative sales price on your house is completed by the real estate agent, and this service is included as part of the 2.2% agency fees. He doesn’t know of any agencies that complete this service in your area and it is standard practice to include this assistance during the consultation process with a real estate agent.

We also discussed in our meeting that a direct financial benefit for wind farm neighbours can be achieved by entry into a voluntary participation agreement. Through this agreement, neighbours, like the host landholders, will receive a direct financial benefit from the wind farm, and in return accept some of the conditions that the host landholders also accept.

In response to your concerns as a neighbour to the wind farm, we are pleased to offer you a participation agreement on the following basic terms.

As indicated in the meeting, this agreement does not have ‘gag clauses’ or take away your right to complain about the wind farm. However, you will see in section 4.7 [see below] of the agreement, that the landholder agrees not to object to any development approval or other application or procedure made or initiated by the developer. Given the wind farm already has got a planning permit this clause is probably of little consequence for you. In addition to this clause section 9 [see below] does require the terms of this letter and attached agreement to remain confidential.

(((( o ))))

4.1(a) The Landholder acknowledges and agrees that the Annual Fee is adequate compensation and consideration for all matters contemplated by this Agreement including (without limitation) any nuisance caused by the construction, use and operation of the Wind Farm.

4.1(b) Without limiting the generality of clause 4.1(a), in consideration of the Annual Fee the Landowner agrees that the Landowner will not:

(i) require the Developer to provide any acoustic suppression or treatment measures in order to minimise any noise impacts resulting from the Wind Farm on the Property or any Dwelling or Permitted Dwelling on the Property (Acoustic Suppression); or

(ii) require the Developer to provide any landscaping treatment to the Property in order to minimise the visual impact of the Wind Farm on the Property or any dwelling on the Property (Landscaping); and

(iii) make any request under the Planning Permit:

(A) for any Acoustic Suppression or attenuation measures; or

(B) for any Landscaping for visual suppression or attenuation measures.

4.3 The Landholder shall not carry out, or allow to be carried out, any development or use of the Property that is likely to unreasonably diminish the security or utility of the Property or the Site for use as part of the Wind Farm. In particular, without the prior written consent of the Developer, the Landholder shall not:

(a) construct any dwelling on the Property additional to the Dwelling and Permitted Dwelling;

(b) erect any device to convert wind energy on the Property, other than a water pumping or other windmill no higher than 25 metres above ground level solely and exclusively for the generation and supply of electricity to the Dwelling, Permitted Dwelling or other buildings and uses on the Property; or

(c) otherwise obstruct or interfere with the potential operation or efficiency of wind turbine generators that form part of the Wind Farm.

4.6 To the extent permitted by law, the Landholder releases the Developer and its Related Persons from any damage, loss, cost, expense or Claim arising from or relating to any impact or effect of the Wind Farm on the Landholder or the Property, including but not limited to impacts or effects created by the construction, use and operation of the Wind Farm.

4.7 The Landholder must not object to any Development Approval or planning or other application or procedure made or initiated by the Developer or any other entity for any use or development of the Site or any neighbouring property that is related to or necessary for the Wind Farm, and must provide all reasonable assistance requested by the Developer for the purposes of obtaining approvals.

9(a) The parties expressly acknowledge that the contents of this agreement (and any documents or information provided by one party to another pursuant to or in connection with this agreement) are confidential and shall not be disclosed to any person except …

Download original document: “Participation Agreement – Moorabool Wind Farm”

Download original letter: “Participation Agreement with the Moorabool Wind Farm – Basic Terms”

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Date added:  April 5, 2016
EconomicsPrint storyE-mail story

Amenity costs of offshore wind farms: Evidence from a choice experiment

Author:  Lutzeyer, Sanja; Phaneuf, Daniel; and Taylor, Laura

Abstract:  We conduct a choice-experiment with individuals that recently rented a vacation property along the North Carolina coastline to assess the impacts of a utility-scale wind farm on their rental decisions. Visualizations were presented to survey respondents that varied both the number of turbines and their proximity to shore. Results indicate that there is not a scenario for which respondents would be willing to pay more to rent a home with turbines in view as compared to the baseline view with no turbines in sight. Further, there is a substantial portion of the survey population that would change their vacation destination if wind farms were placed within visual range of the beach. The rental discounts required to attract the segment of the survey population most amenable to viewing wind farms still indicate that rental value losses of five percent or more are possible if a utility-scale wind farm is placed within eight miles of shore.

Sanja Lutzeyer, McKinsey and Company, Johannesburg, South Africa, and Center for Environmental and Resource Economic Policy, North Carolina State University
Daniel J. Phaneuf, Department of Agricultural and Applied Economics, University of Wisconsin
Laura O. Taylor, Center for Environmental and Resource Economic Policy, North Carolina State University

The amenity costs of offshore wind farms: Evidence from a choice experiment

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Date added:  April 5, 2016
Economics, Property valuesPrint storyE-mail story

Exploring the impact of the proposed Galloo Island energy project

Author:  Nanos Clarkson University Research Collaboration

Conducted for the Town of Henderson, January 2016.

The Galloo Island Wind Energy Facility (henceforth GIWEF) Project was first informally proposed in September 2014 by Albany based Hudson Energy Development LLC under a subsidiary Hudson North Country Wind 1 LLC (henceforth HNCW). Its formal Program Involvement Plan Application occurred in Summer 2015. Its plan comprises 29 turbines located on the privately owned island for an expected 102 MW output. The turbines will be 575 feet high, with blade lengths of 210 feet (Hudson North Country Wind 1, LLC 2015). On Dec. 18, 2015, HNCW sold the project to Apex Clean Energy LLC of Charlottesville, VA.

A key concern of many residents of the Town of Henderson is that the Galloo Island wind facility will negatively impact both property values in the town, as well as economic activity through tourism. These concerns are exacerbated by the fact that the usual benefits which typically accrue to counter potential negative impacts of this type of development, such as payments-in-lieu-of-taxes (PILOTS) or lease payments, are not eligible for residents of the Town of Henderson. As such, the impact of the proposed development on the Town of Henderson is uncertain and requires clarification. This study does not examine environmental benefit / cost impacts for the region as they are beyond the scope of the report as designated by the Town of Henderson.

Key Findings

The Nanos Clarkson Research Collaboration has undertaken a series of analyses, enclosed within the subsequent report, specifically a property value analysis, an economic and jobs analysis, as well as a viewshed analysis. While methodologies (and qualifiers) for the various analyses are highlighted within the report along with report details, the overall general findings can be summarized as follows in terms of the anticipated impacts:

These findings are elaborated in more detail within the subsequent report. It should be noted that this study does not examine environmental benefit/cost impacts for the region as they are beyond the scope of the report as designated by the Town of Henderson. Finally, the report includes a series of view-shed analyses for the Town of Henderson in relation to the proposed Galloo Island development. In addition to the enclosed data and documents, the 3-D viewer can be accessed at: in order to provide a more variable tool for analysis and evaluation.

Download original document: “Exploring the impact of the proposed Galloo Island energy project”

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