Resource Documents: Impacts (128 items)
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Author: Perold, V.; Ralston-Paton, S.; and Ryan, P.
[Abstract] Wind energy is a clean, renewable alternative to fossil fuel-derived energy sources, but many birds are at risk from collisions with wind turbines. We summarise the diversity of birds killed by turbine collisions at 20 wind energy facilities (WEFs) across southwest South Africa. Monitoring from 2014 to 2018 recovered 848 bird carcasses across all WEFs, at a crude rate of 1.0 ± 0.6 birds turbine−1 y−1 at 16 WEFs with at least 12 months of postconstruction monitoring. However, mortality estimates adjusted for detection and scavenger bias were appreciably higher: 4.6 ± 2.9 birds turbine−1 y−1 or 2.0 ± 1.3 birds MW−1 y−1 (n = 14 WEFs with site-specific bias correction factors), which is slightly lower than mean rates reported in the northern hemisphere, but still well within range. A striking result was the high diversity of birds killed: 130 species from 46 families, totalling 30% of bird species recorded at and around WEFs, including some species not recorded by specialist surveys at WEF sites (e.g. flufftails Sarothruridae). Species accumulation models suggest that 184 (±22) species will be killed at these facilities, some 42% of species found in the vicinity of WEFs. This is despite the smaller number of migrants in the study region, compared with the north temperate zone. Diurnal raptors were killed most often (36% of carcasses, 23 species) followed by passerines (30%, 49 species), waterbirds (11%, 24 species), swifts (9%, six species), large terrestrial birds (5%, 10 species), pigeons (4%, six species) and other near passerines (1%, seven species). Species of conservation concern killed include endangered Cape Vultures Gyps coprotheres and Black Harriers Circus maurus, both of which are endemic to southern Africa. Every effort must be made to site wind energy facilities away from important areas for birds, particularly raptors.
V. Perold and P. Ryan, FitzPatrick Institute of African Ornithology, Biological Sciences, University of Cape Town, Cape Town, South Africa
S. Ralston-Paton, BirdLife South Africa, Pinegowrie, South Africa
Ostrich 2020: 1–12. doi: 10.2989/00306525.2020.1770889
Download original document: “On a collision course? The large diversity of birds killed by wind turbines in South Africa”
Mortality limits used in wind energy impact assessment underestimate impacts of wind farms on bird populations
Author: Schippers, Peter; et al.
1. The consequences of bird mortality caused by collisions with wind turbines are increasingly receiving attention. So‐called acceptable mortality limits of populations, that is, those that assume that 1%–5% of additional mortality and the potential biological removal (PBR), provide seemingly clear‐cut methods for establishing the reduction in population viability. 2. We examine how the application of these commonly used mortality limits could affect populations of the Common Starling, Black‐tailed Godwit, Marsh Harrier, Eurasian Spoonbill, White Stork, Common Tern, and White‐tailed Eagle using stochastic density‐independent and density‐dependent Leslie matrix models. 3. Results show that population viability can be very sensitive to proportionally small increases in mortality. Rather than having a negligible effect, we found that a 1% additional mortality in postfledging cohorts of our studied populations resulted in a 2%–24% decrease in the population level after 10 years. Allowing a 5% mortality increase to existing mortality resulted in a 9%–77% reduction in the populations after 10 years.
Peter Schippers, Ralph Buij, Alex Schotman, Jana Verboom, Henk van der Jeugd, Eelke Jongejans
Wageningen Environmental Research, Wageningen University & Research; Environmental Systems Analysis, Wageningen University; Vogeltrekstation – Dutch Centre for Avian Migration and Demography, Wageningen; Animal Ecology and Physiology, Radboud University, Nijmegen, The Netherlands
Ecology and Evolution. Published on line 04 June 2020. doi: 10.1002/ece3.6360
Download original document: “Mortality limits used in wind energy impact assessment underestimate impacts of wind farms on bird populations”
Author: Palmer, William
For 5 years, since the start-up of an array of 140 wind turbines, residents have filed complaints with the Ontario Ministry of the Environment (the regulator), and K2 Wind (the operator). Residents complained that the turbines produce a tonal sound, and that the irritation this produced impacted their sleep, their health, and the enjoyment of their property. To confirm tonality from the wind turbines, this research examined over 200 data examples from two families. These families collected data by two independent methods, a continuously recording system, and by making selected audio recordings. The recorded data was correlated with the wind turbine operational performance, and local weather conditions. The correlated data was analyzed for tonality using international standard evaluation methods. The analysis confirmed over 84% correlation between complaints of irritating conditions, and tonality from 5 dB to over 20 dB. The research also identified deviation between the recommended method for assessing wind turbine tonality of an expert group panel for the industry and the method for compliance monitoring now prescribed by regulations. The deviation can incorrectly reduce tonality calculated to significantly below the actual tonality. Finally, the results showed that the assumption of the regulator to only require assessment of compliance when the resident was downwind of the nearest wind turbine was incorrect. Most complaints arose from other wind directions. Neither was the regulator’s assumption correct that curtailing the wind turbine operation to continue operating at only partially reduced outputs would give remediation. The research concludes that tonality arises consistent with the wind turbine operation, identifying a critical need to revise the practices to prevent chronic irritation.
William K.G. Palmer
Independent Researcher, TRI-LEA-EM, Paisley, Ontario, Canada
Journal of Energy Conservation, Volume 1, Issue 3. DOI: 10.14302/issn.2642-3146.jec-20-3359
Download original document: “Confirming Tonality at Residences Influenced by Wind Turbines”
Author: Cooper, Steven; and Chan, Christopher
Abstract: An issue exists around the world of wind farms that comply with permit conditions giving rise to noise complaints. Approval limits are normally expressed in A-weighted levels (dB(A)) external to residential receivers. The distance from the wind farm to residential receivers can result in diffculty in establishing the dB(A) contribution of the wind farm, as the overall noise includes background noise that can provide masking of the wind turbine noise. The determination of the ambient background at a receiver location (without the influence of the wind farm) presents challenges, as the background level varies with the wind and different seasons throughout the year. On-off testing of wind farms does not normally occur at high wind farm output and limits this approach for acoustic compliance testing of a wind farm. The use of a regression analysis method developed more than 20 years ago is questioned. Anomalies with respect to compliance procedures and the regression method of analysis based on real-world experience are discussed.
Steven Cooper and Christopher Chan
The Acoustic Group, South Windsor, Australia
Acoustics 2020, 2, 416–450; doi:10.3390/acoustics2020024