Wind offers a remarkable source of green energy - renewable, widespread and pollution free. The big turbines, which look like high-tech windmills and turn wind into electricity, are going up on windswept sites around the United States. But as wind farms proliferate, an unforeseen problem is turning up: Migrating bats are crashing into the spinning blades of the turbines in disturbing numbers.
This recently discovered issue could get worse in a hurry. Wind power is the fastest-growing segment of the U.S. energy industry, and tax subsidies that are expected from Congress this year could trigger a construction boom that will put thousands of wind turbines on high-risk ridges and mountaintops, especially in the Eastern United States.
To prevent serious threats to bats, Bat Conservation International is working with industry and federal agencies to determine exactly why bats are fatally flying into the turbines and how that can be prevented. The Bats and Wind Energy Cooperative includes BCI, the American Wind Energy Association (AWEA), the U.S. Fish and Wildlife Service and the U.S. Department of Energy's National Renewable Energy Laboratory (NREL).
The issue of bat deaths at wind farms was widely neglected in early wind-power assessments simply because bats, unlike birds, have no broad-based legal protection. Reports of two or three bats per turbine being killed each year at some facilities seemed a relatively small price to pay for clean energy. Such figures, however, can be misleading. We now realize that many more bats may have been killed but not counted.
Weekly surveys last summer beneath 44 giant turbines at West Virginia's Mountaineer Project revealed that an estimated 2,095 bats of seven species had been killed. However, since no surveys were conducted during the first half of the peak mortality period in August and since scavengers likely removed unknown numbers of bats during the seven-day intervals between searches, the total number of bat fatalities could easily approach 4,000.
The Mountaineer Project is the first large wind-energy site in eastern North America to be built on a high ridgeline. Exceptional bat kills are also being reported at a Tennessee wind farm on a mountaintop; 85 bats are being killed there each year at just three turbines. These are the only two wind farms built so far on ridges and mountaintops in the Eastern states.
For more than a decade, biologists have been raising concerns about ridge-top wind sites as potential threats to migrating birds, but bat migration was rarely considered. With major bat mortality confirmed at the only two Eastern wind-turbine projects located on ridges and mountaintops, the potential for devastating cumulative impacts is clear.
To address this urgent issue, BCI hosted a planning session last December that brought together leaders from the Fish and Wildlife Service, NREL and AWEA. The group agreed to sponsor a Wind Power Generation Technical Workshop to develop an expert consensus on how to prevent further bat deaths. That meeting, funded by AWEA and NREL and hosted by FPL Energy (America's largest wind-power producer), was held last February in Juno Beach, Florida. Top bat experts from the United States, Canada and the United Kingdom developed the research priorities they consider essential to preventing additional bat kills.
Solutions will not be found until detailed observations are made, and these will require long hours of daily and nightly monitoring at problem sites. Night-vision and thermal-imaging equipment, echolocation detectors and marine radar have all been identified as tools that may help in assessing problems. It is imperative that we immediately develop reliable methods for identifying and avoiding highly sensitive locations, stop attracting bats to turbines, act to reduce their vulnerability, learn to predict and respond effectively to high-risk time periods, or delay further construction along sensitive ridge and mountaintop areas.
Armed with the advice of leading experts on bats and relevant technologies, members of the Bats and Wind Energy Cooperative agreed to jointly fund a Project Coordinator at BCI. Ed Arnett, a biologist of exceptionally relevant experience, officially assumed that position June 15. His immediate goals include developing a project website for information sharing, completing guidelines for risk assessment and mortality studies, facilitating required peer review and communication, and organizing and participating in field research.
The new Bats and Wind Energy Cooperative has been formed. Expert guidance has been obtained and priorities have been set. But nothing can be accomplished until we make essential observations and find and implement solutions. Cooperation in funding the required research will be the true test of our collaboration.
