Researchers Seek to Reduce Bat Deaths at Wind Turbines

[Guest Dr. Ed Arnett]

The Bats and Wind Energy Cooperative (BWEC), a unique government-industry-conservation group alliance, has begun testing the effect of stopping wind turbines during low wind conditions to avoid

killing bats. The study, the first of its kind in the U.S., would also determine the reduction, due to shutdowns, in the amount of electricity generated.

 

"The U.S. Fish and Wildlife Service (Service) is concerned that several species of bats, including potentially endangered bats, are killed each year by wind turbines," said Alex Hoar, the Service's

northeast coordinator for review of wind power projects. "The Service is pleased to be helping fund this precedent-setting study to test if slightly changing the way a wind turbine operates can

substantially reduce or even avoid killing bats."

 

IBERDROLA RENEWABLES offered its Casselman Wind Power Project site in Pennsylvania for the experiment and is also providing funding for it. “We are proud to offer our Casselman site for this important experiment and fully support efforts of the BWEC,” said Andrew Linehan, director of permitting for the company. “We believe this is the responsible thing to do and recognize there is an impact on bats that requires scientific study. We’re committed to hosting this effort, which represents a new area of investigation for the wind industry,” Linehan said.

 

In 2004, BWEC (http://www.batsandwind.org) was formed by Bat Conservation International (BCI), the American Wind Energy Association (AWEA), the Service, and the U.S. Department of Energy’s

National Renewable Energy Laboratory (NREL) to learn why bats are being killed at wind energy facilities and how deaths can be prevented.

 

Since that time, BWEC scientists have learned much about patterns of bat deaths and the relationships between weather and interactions of bats with wind turbines. Key findings suggest bat

fatalities occur primarily on low wind nights when turbines are operating at low power, but in some cases the turbine blades are rotating at or near their maximum speed. Scientists hypothesize that

shutting down turbines in times of low wind during periods of high bat activity could significantly reduce fatalities, with modest reduction in power production and associated economic impact on

project operations.

 

“I’m thrilled that this critical experiment is under way,” said Dr. Merlin Tuttle, Founder and President of BCI. “Our purpose is to work together on determining causes and solutions as quickly as possible.” Bats, though often ignored and falsely besmirched, are vital to the health of the environment and to many human economies. They are primary predators of night-flying insects, including many major agricultural pests, while some are important pollinators and seed dispersers. Bat kills have been high at many facilities, especially in the eastern United States, though it remains unclear why some bat species seem susceptible to collisions with the turbines and changes in atmospheric pressure immediately downwind of the turbine blades These fatalities raise concerns about potential

cumulative impacts on bat populations at a time when many species of bats are known or suspected to be in decline from other non-wind energy-related factors, and the use of wind energy is increasing worldwide.

 

“The industry is working cooperatively with diverse partners toward solutions, and this study is critical to those efforts,” said AWEA Deputy Executive Director Tom Gray. “AWEA is very pleased

with the progress the cooperative has made over the past several years and this study represents a key milestone in moving forward with developing solutions and bringing the best science to bear on this issue."

 

“The curtailment experiment is a great first mitigation method and it may provide an approach to reduce the impact to bats at wind plants, but we need to fully understand why and how bats are being

killed in order to devise methods to avoid the impact,” said Bob Thresher, Wind Research Fellow at the NREL and former Director of the Department of Energy’s National Wind Technology Center.

The BWEC partners are hopeful that this field experiment will yield a solution to support wind power production in concert with wildlife protection and conservation.