Bats Interacting with Wind Turbines

from: Horn et al. 2008 Journal of Wildlife Management 72:1 123-132

The video clips on this site are presented to support a study that appears in the Journal of Wildlife Management. This study deals with the recent finding that forest-dwelling bats are often found dead beneath operating wind turbines at wind energy facilities. We used thermal infrared video cameras to record the flight behavior of bats at night near these turbines in an attempt to understand the cause of these fatalities. We encourage you to read the study so that you will have a context as you view the clips.

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Investigating the Turbine Tower and Nacelle (power generating unit)

One or more bats repeatedly investigate the turbine blades and tower (monopole).

A bat investigates the turbine tower (monopole), showing typical ‘touch-and-go’ behavior.

A bat repeatedly investigates and briefly lands on the turbine tower while the rotor spins slowly.

A bat investigates the nacelle.

A bat investigates moving blades.

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Investigating and Chasing Turbine Blades

A bat investigates and lands on a still blade.

Bats chase blade tips (1) or are possibly caught in tip vortices.

Bat chases blade tip (2) or is possibly caught in tip vortex.

A bat performs ‘touch-and-go’ behavior on the turbine tower, then a stopped blade.

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Bat Avoidance Behavior

A high-flying bat narrowly avoids being struck by moving blades.

A bat reacting to the movement of (and perhaps avoiding) turbine blades.

A bat narrowly avoids being struck, or receives a glancing blow from a passing turbine blade

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Contact with Blades

A bat is struck on the downswing of a blade.

A bat is struck by a rotating turbine blade in the lower portion of the rotor-swept zone.

A bat is struck by a rotating blade from below as the blade swings upward.

A bat is struck by a fast-moving blade.

A bat is struck by a downward-moving turbine blade.

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Birds

A flock of birds flies high overhead in a V formation.

A bird flies high above the turbines.

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Multiple Bats

Three bats flying low and close to the camera.

Multiple bats fly near an operating turbine.

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Height Reference: The altitude of bats relative to the height of moving turbine blades

Height example: A bat within the area swept by moving turbine blades. An insect also flies low and close to the camera.

Height example: A bat flying above the reach of moving turbine blades.

Jason W. Horn, Center for Ecology and Conservation Biology, Department of Biology, Boston University
Edward B. Arnett, Bat Conservation International, Austin, Texas
Thomas H. Kunz, Center for Ecology and Conservation Biology, Department of Biology, Boston University

Download “Behavioral Responses of Bats to Operating Wind Turbines”

Twenty-three videos illustrating several aspects (investigating the turbine tower and nacelle, investigating and chasing turbine blades, bat avoidance behavior, contact with blades, birds, multiple bats, and height reference) of bat flight at night around wind turbines are available from Boston University: click here.

We value this opportunity to comment on the draft directives. Given the complexity of the proposed changes, the level of expertise within our group and the multitude of documents where additions and changes are found, we struggled in the performance of a comprehensive analysis and the determination of the possible affects for Pendleton County and its national forests areas.

Our comprehensive analysis started with the USDA Forest Service website and the Forest Service Mission, Motto, Vision and Guiding Principals. We have concluded that it is impossible to justify any Forest Service decision to permit the industrialization of one acre of the 193 million acres, including the pristine mountain tops in the pristine National Forests of Pendleton County, West Virginia, of the Commons placed under its management by “We the People” with industrial wind energy projects. It just doesn’t fit, It doesn’t fit the Mission, It doesn’t fit the Motto, It doesn’t fit the Vision and It doesn’t fit the Guiding Principals. The current political wind is in favor of the development and energy interests, thereby significantly influencing the pressure on the natural environment. If the trend continues, how much of the National Forest will remain when our fast expanding population will likely be desperate for a little breathing room in the future, 25, 50 and 100 years from today? …

January 20, 2008

Larry V. Thomas, Vice President
Friends of Beautiful Pendleton County, Inc.
PO BOX 218
FRANKLIN, WV 26807

To preserve our rich heritage, protect the precious natural environment and ensure citizens receive responsible, factual information

Download “USFS Public Comment Letter”

Also see the letter from The Wilderness Society here at National Wind Watch.

• Introduction: Huge windmill “plants” cannot supply “green” electricity
• Huge windmills will not cause any coal-fired plant to go out of service and therefore will not reduce greenhouse gases
• It is a fallacy to contend that electricity produced by huge windmills can be considered for “renewable energy credits”
• Substantial energy is lost using the current methods of electricity production
• New technology and energy storage can provide realistic renewable energy
• Monetary incentives drive the continued construction of useless huge windmills
• Huge windmill “plants” cause cumulative negative impacts
• Huge windmills kill bats which control disease-carrying insects
• Conservation, preservation, and new technology can provide the solution

Go to: ‘Huge Windmill “Plants” Fail’

Our first objection concerns Mr. Hathaway’s basic premise that wind-powered generation will reduce the need for coal-fueled generation. The recent National Academies report on Environmental Impacts of Wind-Energy Projects compared U.S. Department of Energy projections for growth in electricity demand with projections for growth in wind generation. Between 2005 and 2020, annual U.S. electricity demand is projected to increase by more than a trillion kilowatt-hours (kWh). The projected increase in wind generation is expected to account for only 3.5% to 19% of this increase in total demand. In other words wind development may somewhat slow the growth in demand for electricity from traditional sources — but it will not reduce the demand for electricity from traditional sources.

Our second objection concerns Mr. Hathaway’s estimation of “18 acres of saved mountain top” per turbine. His calculations depend on a string of questionable data and assumptions.

• He relies on data published in Grist magazine and the Appalachian Voices newsletter as the basis for calculating that an acre of strip mining/ mountaintop removal yields 6,200 tons of coal. In contrast, EPA’s 2003 Draft Environmental Impact Statement on Mountaintop Mining/Valley Fill indicates that an average acre of mountaintop removal in West Virginia yields 10,000 tons of coal.*1

• He assumes that 100 MWh of wind generated electricity will displace 88 MWh of coal generated electricity — based on a report he submitted to the Virginia State Corporation Commission. We previously responded to this report, noting that it relies extensively on confidential and summary data that are not available or provided for independent review and evaluation. As we argued in our response, this lack of transparency is well outside the norm for either scientific assessment or public policy deliberation.*2

• He assumes that wind-generated electricity will only displace generation associated with coal that is mined through strip mining/mountaintop removal. According to the U.S. Energy Information Agency, more than 60% of coal mined in the Appalachian region is extracted from underground mines.

• His estimate of per-turbine electricity generation is based on 2.5 MW wind turbines, operating at a 35% capacity factor, with a lifespan of 30 years. There are no 2.5 MW turbines installed on central Appalachian ridges, most are 1.5 MW, and the largest are 2.0 MW. For turbines installed in the U.S. since 2000, the cumulative annual capacity factor (CF) in 2004 was 30% — and the average capacity factor (CF) of all the windplants in the eastern U.S. is less than 30%.3 The rated operational lifetime for turbines installed to date in West Virginia is 20 years.*4

The combined effect of these questionable data and assumptions is an unrealistically high estimate of potential mountaintop removal offset. We have used original data sources and more-realistic assumptions to obtain a more-credible estimate.

• We rely on the above cited EPA estimate for West Virginia of 10,000 tons of coal per acre of area mined by mountaintop removal.

• We have less-optimistic expectations for turbine performance, based on current technology and actual observation. That is, our calculations are based on 2.0 MW turbines, with a capacity factor of 30% and an operational lifespan of 20 years.

• We calculate a mountaintop removal offset (MRO) of 22.8%, which is the product of and accounts for:

• Potential coal displacement, based on the percentage of Appalachian region electricity generated with coal (65.3%).*5
• Potential surface mine displacement, based on the percentage of Appalachian region coal extracted by surface mining (34.9%).*6

• Consistent with the Hathaway analysis and EIA statistics, we further assume that 1 ton of coal is equivalent to 2 MWh of electricity generation.*7

We apply the above assumptions to estimate a potential perturbine coalfield offset: (2.0 MW × 30% CF × 20 yr × 8760 hr/yr × 22.8% MRO) / (10,000 tonscoal/ acre × 2 Mwh/ton-coal) = 1.2 acres.

This 1.2 acre estimate is substantially less than the 40 to 50- acre estimate reported in the Wind Chill article or the 18-acre estimate subsequently provided by Mr. Hathaway.*8 Consider that modern turbines are installed on ridgelines at approximately 8 turbines per mile and that each wind energy project may clear an average of 3-5 acres of forest per turbine. The impact on wildlife and habitat due to forest fragmentation is an even larger issue when turbines and connecting roads are constructed on forested ridges, with a per turbine loss of 15 to 20 acres of interior forest habitat.*9

It is not our intention to compare the ecological impact of mountaintop removal coal mining and ridgeline wind energy development. It is our intention to provide some perspective. We should all be concerned about the environmental and human costs of mountaintop removal and other forms of coal mining. We suggest, however, that it is not in anyone’s interest to exaggerate the potential role of wind development in addressing this problem.

Notes

*1. U.S. EPA. 2003. Draft Programmatic Environmental Impact Statement for Mid-Atlantic Mountaintop Mining — Chapter 3, page III.J, 17 (see www.epa.gov/region3/mtntop/eis.htm)
*2. Mr. Hathaway’s submission to the Virginia State Corporation Commission and our submission in response are posted on the Virginia Wind website. (see www.vawind.org/Assets/Docs/Comments/ Hathaway_and_Jacobsen_070506.pdf and www.vawind.org/Assets/Docs/Comments/ Response_To_HNWD_Backdown_Study_080906.pdf)
*3. Energy Information Administration. 2004. Form EIA-860, Form EIA-906, and Form EIA-920 Databases.
*4. Det Norske Veritas. 2004. Type Approval of NM72C — Approval number A-642052-5 [NM72C is the model number of the 1.5-MW NEG Micon wind turbines installed at Mountaineer windplant in WV; Appendix 1 on p. 3 of the Approval indicates this turbine's "Design life time" is "20 years". See also www.wt-certification.dk/UK/Approved.htm]
*5. U.S. Environmental Protection Agency. 2006. eGRID2006: Emissions and Generation Resource Integrated Database (containing 2004 information) — available via: www.epa.gov/solar/egrid/index.htm (Region defined as MD, PA, VA, and WV.)
*6. www.eia.doe.gov/cneaf/coal/page/acr/table7.pdf (Region defined as MD, PA, VA, and WV.)
*7. www.eia.doe.gov/neic/infosheets/coaldemand.html
*8. Use of Mr. Hathaway’s 88% coal-displacement factor, instead of the 65.3% factor we apply, results in a 1.6 acre per turbine offset, as opposed to the 1.2 acre per turbine offset we calculate.
*9. www.kutztown.edu/acad/geography/wildlife&windconf/Speaker_Presentations/Boone_GIS.pdf

… these provisions are badly flawed, in that they entirely disregard the serious environmental concerns that are raised by industrial wind-energy development in the mid-Atlantic region. Those concerns have been articulated by, among others, an expert study committee of the National Academy of Sciences, the U.S. Fish and Wildlife Service, and the U.S. Government Accountability Office, as well as numerous citizens of this state in proceedings before the West Virginia Public Service Commission. …

A fair reading of those provisions suggests that they are based on the entirely erroneous assumption that such development would have only positive impacts on West Virginia. …

… in fashioning a state energy plan, it is critically important to take into account not only the approved projects, but also the plans of developers to build additional projects in our state. The available information indicates that out-of-state developers have targeted West Virginia, and if they are allowed to have their way, they will build their huge industrial projects on mountain ridges throughout our state. …

Furthermore, according to the findings of the National Academy of Sciences study committee, the performance of wind-energy projects in reducing harmful atmospheric emissions will be as disappointing as their output of electricity. …

While the benefits of wind-energy development are limited, the environmental concerns raised by the construction and operation of wind turbines in our region are extensive. Those concerns include impacts on wildlife, particularly birds and bats, and impacts on scenic mountain views. …

One other point on the environmental impacts that needs to be highlighted is that it is necessary to evaluate not only the impacts of each particular project, but also the cumulative impacts of building all the projects that developers are planning. …

Briefly stated, the [state energy] plan should indicate support for only those industrial wind-energy projects that are properly sited under established standards that protect the environment, including standards that protect wildlife and scenic mountain views. …

Download “Letter from Rep. Mollohan to W. Va. Division of Energy”

Of particular concern is the cumulative effect of continuing wind energy development. Based on existing studies and the proposal queue for the mid-Atlantic grid, they project annual bat fatilities of up to 111,000 by 2020.

Abstract:  At a time of growing concern over the rising costs and long-term environmental impacts of the use of fossil fuels and nuclear energy, wind energy has become an increasingly important sector of the electrical power industry, largely because it has been promoted as being emission-free and is supported by government subsidies and tax credits. However, large numbers of bats are killed at utility-scale wind energy facilities, especially along forested ridgetops in the eastern United States. These fatalities raise important concerns about cumulative impacts of proposed wind energy development on bat populations. This paper summarizes evidence of bat fatalities at wind energy facilities in the US, makes projections of cumulative fatalities of bats in the Mid-Atlantic Highlands, identifies research needs, and proposes hypotheses to better inform researchers, developers, decision makers, and other stakeholders, and to help minimize adverse effects of wind energy development.

Download “Ecological impacts of wind energy development on bats”

Download “Relationships between Bats and Wind Turbines”

Download “Friends of Blackwater Complaint for Declaratory and Injunctive Relief”

Download “Mollohan letter to WVPSC”