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July 2011, Volume 9, Number 7
‘Curtailing’ bat fatalities


A study led by Bat Conservation International confirms that curtailing wind turbines – temporarily shutting them down during low-wind periods at night – could reduce bat fatalities at wind-energy facilities by up to 93 percent with minimal losses to annual power production.

The research was featured on the cover of Frontiers in Ecology and the Environment, a journal of the Ecological Society of America.

Wind is an extremely popular source of renewable energy and it is generally considered environmentally clean. But wind farms often take an alarming toll on wildlife, especially birds and bats that encounter the spinning blades of wind turbines. BCI scientists have been exploring solutions to this problem since 2003 through the Bats and Wind Energy Cooperative – an alliance of state and federal agencies, private industry, academic institutions and non-government organizations. BCI leads the Cooperative.

The latest study, conducted at the Casselman Wind Power Project in Pennsylvania, found that applying curtailment procedures to all 23 of the site's turbines during bats' 2½-month migration period would reduce total electricity output by less than one percent for the year.

Lead author Ed Arnett, BCI's Director of Programs, discussed the study in a podcast for the Ecological Society. It can be heard at: www.frontiersinecology.org/beyond/

Arnett and Wind Energy Project Manager Michael Schirmacher also represented BCI in Trondheim, Norway, at the first international conference on wind energy and wildlife. The session dramatically illustrated the worldwide impacts of accelerating wind-energy development on wildlife of many kinds. More than 300 participants from 30 countries shared their research and experience in managing this alternative energy source.

Arnett served on the science program committee and was part of an expert panel on challenges and solutions. Schirmacher presented a poster on research that attempts to utilize acoustic deterrents to reduce bat kills at turbines.

The deterrents broadcast ultrasonic noise that is designed to interfere with bats' echolocation system to such an extent that they steer clear of the turbines.  The study found that using deterrents reduced bat fatalities by 18 to 62 percent. That is significantly less than the reductions from curtailment, however, which suggests that this technology is not yet ready for wide-scale deployment. Researchers continue modifying and testing devices in hopes of developing a bat-saving system for widespread use.

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All articles in this issue:
Bats in the News
The Fort Drum Military Installation in northern New York is home to the U.S. Army's fabled 10th Mountain Division. It is also ...

‘Curtailing’ bat fatalities
A study led by Bat Conservation International confirms that curtailing wind turbines – temporarily shutting them down during ...

Apply for a BCI Scholarship
Knowledge is crucial to protecting bats. And Bat Conservation International has been helping to increase scientific information ...

Unless otherwise noted, all images are copyright ©Merlin D. Tuttle and/or ©Bat Conservation International