Preliminary Study Tackles Wind Power, Bat Issues

Bat carcasses aren’t the standard quarry for hunting dogs. But Luna, a Chocolate Labrador retriever owned by Ed Arnett of the organization Bat Conservation International (BCI), had a good six weeks during the summer to practice her bat searching skills. She was one of two dogs, and many people, to work on the first study for the Bats and Wind Energy Cooperative (BWEC) at the 66 MW Mountaineer wind power production farm on Backbone Ridge near Thomas, West Virginia.

The six-weeks spent on daytime mortality searches and nighttime bat watches was a first for researchers and the wind industry, who have concentrated on bird habits around wind turbines up until now. “We really want to get a handle on what’s happening on the ground,” said Laurie Jodziewicz, a communications and policy spokeswoman for the American Wind Energy Association (AWEA). “One of the things that the wind industry wanted to do was get right on this.” Mountaineer, which is owned by Florida Power and Light (FPL) Energy, came on-line as a power production facility in 2003. A two-month long study to determine bird habits in the area was done as part of establishing the facility, but researchers found some unexpected casualties around the turbines. Over the course of the bird study, researchers also found 475 dead bats. Jim Lindsay, who is the principal environmentalist for FPL, said the total bat mortality rate over the two-month period of the bird study at Mountaineer is statistically closer to 2,000 bat kills. The statistical estimate was reached by factoring in the number of bat carcasses researchers didn’t find, either because scavengers had carried away the carcasses or the bat bodies were hidden in the grass. No matter the number, it was obvious to many people that there was a new problem for the wind industry. In February of 2004, AWEA met with FPL, BCI, the United States Fish and Wildlife Service, and the National Renewable Energy Laboratory to form the Bats and Wind Energy Cooperative. All of the organizations dedicated time, money, or both to the cooperative’s research effort because they knew wildlife mortalities weren’t something to ignore. No one had a good answer as to why the bat mortality rate seemed so high, but researchers had a good place to start from. Bat migrations occur during the fall, so the cooperative scheduled a study at Mountaineer to determine how bats “interact” with wind turbines. Interact seems like a funny word to use when bats are getting knocked out of the air by turbine blades. But during the study from July 31 to September 12, Arnett said he definitely saw bats that were curious about the new items in their habitat. During one night of observation, he watched a bat explore a blade on a turbine that wasn’t working. Out of 44 turbines at the Mountaineer site, the only one that didn’t produce a nightly bat death toll was the turbine that was out of service. Flying bats never dove straight toward the turbine blades either, Arnett said. A bat’s flight pattern during feeding is very erratic because the creature uses sonar to detect potential prey and has to move around to zero in on an object. Bugs can congregate around the lights on a turbine, but feeding doesn’t seem to be the only reason that bats choose to fly near the spinning blades. “We don’t know just exactly what the attraction is,” Arnett said. “But they are interested in something.” Staff and interns for BCI compiled all of the data they gathered through physical searches, thermal imaging, radar studies and ultra sonic detection records into presentations for the National Wind Coordinating Committee in Washington D.C. How bat populations are affected because of turbine related deaths isn’t the only issue. “What’s jeopardized really isn’t the wind development of one facility,” Jim Lindsay said. “It’s the wind industry overall.” This isn’t the first time the wind industry has had faced similar environmental challenges. Altamont Pass in California is one of the more infamous sites of bird deaths associated with wind turbines. AWEA’s Jodziewicz said it was the first site to really bring the public and wind industry’s attention to the issue how turbines can affect birds. In August of this year, the California Energy Commission released a study highlighting mitigations efforts that could reduce the number of bird deaths at any wind farm. But the image of turbines as a detriment to bird, and now bat, species has plagued the wind industry since at least the early 1980s. “We want to be good stewards,” Jodziewicz said. “We want to respond to these issues as soon as we can.” The battle for clean energy resources can’t afford to shut down completely and wait for the study results. Energy production in America is mostly provided through coal-fired and nuclear-powered plants. Though there may not be dead birds at the base of a smokestack, energy production across the nation is detrimental to the environment in some not so instantly noticeable ways. Steve Clemmer, who is a research director for the Clean Energy Program at the Union of Concerned Scientists, said acid rain and mercury emissions from coal plants are just as likely, if not more, to kill area wildlife. “A lot of people forget the big picture, that there’s climate change and global warming,” he said. Among the litany of statistics that Clemmer has at his disposal is that global warming could lead to the extinction of 20 bird species by the year 2050. A conservative estimate on bird deaths from AWEA states that for every 30,000 avian mortalities caused by human-made circumstances, only one death is because of a wind turbine. No energy source is benign, Clemmer said. People have to remember that a “not in my backyard” attitude about an energy source means, perhaps, a worse source will be used elsewhere. The true effect of 2,000 bat kills in two months should be weighed against the total size of the bat population in an area as well, according to Lindsay. Industry officials should try to mitigate the deaths, but they also need to know what the overall affect on the bat population is. “There certainly must be a place where these (turbines) can be placed with low risk to bats and birds,” Arnett said. A final report on the study findings won’t be available from Bat Conservation International until February 2005, according to Arnett. The numbers researchers gathered and methods they tested during the six-week study are only the beginning of a long and hard look at why bats are being killed by wind turbines. Now that they have established how to conduct a study of bat habits around wind turbines, the Bat and Wind Energy Cooperative can work on answering the question of how to create a wind farm environment that isn’t a danger to bat colonies.


  • Renewable Energy World's content team members help deliver the most comprehensive news coverage of the renewable energy industries. Based in the U.S., the UK, and South Africa, the team is comprised of editors from Clarion Energy's myriad of publications that cover the global energy industry.

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