Bat Mortality at Wind Turbines in Northwestern Europe

Abstract

ACKNOWLEDGMENTSThis study was conducted under the auspices of the Bats and Wind Energy Cooperative. We wish to thank the American Wind Energy Association (AWEA), Bat Conservation International (BCI), the National Renewable Energy Laboratory-Department of Energy (NREL), and the U.S. Fish and Wildlife Service (USFWS) for partnering to form the Bats and Wind Energy Cooperative (BWEC). Tom Gray (AWEA), Alex Hoar (USFWS), Bob Thresher (NREL), and Merlin Tuttle (BCI) provided oversight for the BWEC the project.We wish to thank the U.S. Fish and Wildlife Service, donors to BCI, the National Renewable Energy Lab, and Iberdrola Renewables for funding the curtailment study at the Casselman Wind Project in 2008. We are indebted to Holly McCready, Jeff Miller, Erica LaMore, Mario Desilva, Brian Farless, Paula Shover, Ryan Claire, and Ann Zurbriggen for their dedication in the field and collecting and managing the data throughout the study. We thank Iberdrola Renewables employees, in particular Andy Linehan, Sam Enfield, Jason Bell, Scott McDonald, Dave DeCaro, and Chris Long, for their support and efforts to make this study happen and run smoothly. Zac Wilson (BCI) conducted all GIS analysis for the study. Finally, we appreciate the support and hospitality of the private landowners that graciously allowed access to their lands for this study; they should be commended for supporting proactive research for solving wildlife and wind energy issues. EXECUTIVE SUMMARYWe implemented the first U.S.-based experiment on the effectiveness of changing turbine cut-in speed on reducing bat fatality at wind turbines at the Casselman Wind Project in Somerset County, Pennsylvania. Our objectives were to 1) determine the difference in bat fatalities at turbines with different cut-in-speeds relative to fully operational turbines, and 2) determine the economic costs of the experiment and estimated costs for the entire project area under different curtailment prescriptions and timeframes.Twelve turbines of the 23 turbines at the site were randomly selected for the experiment and we employed three treatments at each turbine with four replicates on each night of the experiment: 1) fully operational, 2) cut-in speed at 5.0 m/s (C5 turbines), and 3) cut-in speed at 6.5 m/s (C6 turbines). We used a completely randomized design and treatments were randomly assigned to turbines each night of the experiment, with the night when treatments were applied being the experimental unit. We conducted daily searches at the 12 turbines from 26 July to 10 October 2008. During this same period, we also conducted daily searches at 10 different turbines that were part of a complementary study to determine if activity data collected prior to construction with acoustic detectors can be used to predict post-construction fatalities, and to meet permitting requirements of the Pennsylvania Game Commission's (PGC) voluntary agreement for wind energy (herein referred to as "PGC" turbines). These 10 turbines formed an alternative 'control' to the curtailed turbines. We perfo...

Behavior of bats at wind turbines

“…We regularly observed hoary bats and eastern red bats (Lasiurus borealis) flying in under the bottom of the leeward nacelle and making close approaches to the recessed exhaust port (Movie S4). Although we did not see clear evidence of bats consistently trying to land on turbines, we frequently observed bats approaching the monopoles very closely, as previously reported (4,13,34). The high proportions of close approaches focused on nacelles and monopoles (Table S1) are consistent with bats trying to find places to land.…”

“…In North America, tree bats compose more than three-quarters of the reported bat fatalities found at wind-energy sites (6,9), although there is a paucity of information from the southwestern United States and Mexico. Similar patterns occur in Europe (4). Another prominent pattern in bat fatality data from northern temperate zones is that most fatalities are found during late summer and autumn, sometimes with a much smaller peak of fatality in spring (4,6).…”

“…Similar patterns occur in Europe (4). Another prominent pattern in bat fatality data from northern temperate zones is that most fatalities are found during late summer and autumn, sometimes with a much smaller peak of fatality in spring (4,6). Concurrent involvement of species with shared behaviors suggests that behavior plays a key role in the susceptibility of bats to wind turbines, and that tree bats might somehow be attracted to wind turbines (8).…”

“…The recent phenomenon of widespread fatalities of bats at utility scale wind turbines represents a new hazard with the potential to detrimentally affect entire populations (3,4). Bat fatalities have been found at wind turbines on several continents (3)(4)(5)(6), with hypothesized estimates of fatalities in some regions ranging into the tens to hundreds of thousands of bats per year (4,6). Before recent observations of dead bats beneath wind turbines, fatal collisions of bats with tall structures had been rarely recorded (7).…”

“…energy development | sensory perception | video surveillance | wildlife | wind energy B ats are long-lived mammals with low reproductive potential and require high adult survivorship to maintain populations (1,2). The recent phenomenon of widespread fatalities of bats at utility scale wind turbines represents a new hazard with the potential to detrimentally affect entire populations (3,4). Bat fatalities have been found at wind turbines on several continents (3)(4)(5)(6), with hypothesized estimates of fatalities in some regions ranging into the tens to hundreds of thousands of bats per year (4,6).…”