Texas leads the nation in wind energy generation with thousands of wind turbines throughout the state. This is a boon for clean energy generation but not for the state’s large population of bats, which are often drawn to the spinning turbines.
To help discourage them from approaching, Duke Energy Renewables is working with NRG Systems, Inc. to install an innovative bat deterrent system. The technology uses ultrasound to block the sonar that bats use to navigate in the dark, causing them to avoid areas around the wind turbines.
Duke Energy Renewables will install NRG Systems’ Bat Deterrent System over a five-year period at 255 wind turbines at its Los Vientos III, IV and V wind sites beginning in July 2019. This will mark the first commercial deployment of the Bat Deterrent System in the continental U.S.
The Rio Grande Valley, where the Los Vientos wind projects are located, has a robust population of common bat species that provide tremendous pest control benefits to local farmers and ranchers. Maintaining this local bat population was the impetus behind a two-year field study conducted by Duke Energy Renewables, NRG Systems and Texas State University. The study found that the Bat Deterrent System reduced overall bat fatalities by 50% around wind turbine locations at Los Vientos III, IV and V.
“At Duke Energy, we’re focused on generating clean, renewable energy for customers while also protecting the native wildlife around our generation facilities,” said Greg Aldrich, lead environmental scientist with Duke Energy. “With this new technology, we’re pleased that we’ll be able to significantly reduce the impacts on bats and continue our environmental leadership in this area.”
“We are endlessly grateful to the entire Duke Energy team for the crucial role they played in bringing this technology to market,” said Brogan Morton, senior product manager at NRG Systems. “Their participation in the two-year study coupled with their willingness to share their expertise with us helped us create a commercially viable Bat Deterrent System that we expect will have considerable benefits both in terms of wildlife conservation and renewable energy generation. Their implementation of our systems at Los Vientos is the next chapter in what has so far been a successful and rewarding collaboration.”
How NRG Systems’ Bat Deterrent System works
The NRG Systems’ Bat Deterrent System is mounted on the nacelle (the covering that houses all the generating components) of the wind turbine. Once installed, it emits continuous ultrasonic energy in the same frequency range as the bat’s bio sonar used to orient, forage and locate objects.
When bats enter the airspace where the deterrent units are operating, the ultrasonic energy essentially disrupts their bio sonar, making it difficult for them to find food sources and navigate their surroundings. This effectively minimizes bats’ interactions with the wind turbines. The ultrasonic field emitted by the Bat Deterrent System does not harm the bats and quickly dissipates beyond the turbine rotor sweep. The sound cannot be heard by humans and does not impact other wildlife or livestock.
Research study methodology and results
Duke Energy worked with researchers from Texas State University and NRG Systems to field test the Bat Deterrent System on 16 2-megawatt wind turbines located throughout Los Vientos III, IV and V in Starr County, Texas.
- Field testing was conducted on eight control and eight treatment randomly assigned turbines on a nightly basis between 2017 and 2018.
- The trials showed a 50% reduction in overall bat fatalities during the field testing period.
- The Brazilian free-tailed bat and hoary bat showed the greatest fatality reductions. The hoary bat, a bat species of recent conservation concern, showed a reduction of 78%.
Sara Weaver, PhD, biology lecturer at A&M, San Antonio, who led the Los Vientos study during her doctoral candidacy at Texas State University, said, “Our results from this robust, two-year study indicate that NRG’s acoustic deterrents significantly reduce Brazilian free-tailed bat and hoary bat fatalities. Based on these results, the technology is a promising tool for reducing bat fatalities at wind turbines.”
Funding for the research came from the Texas Parks & Wildlife Department and Bat Conservation International.
“Bats play an important role in our ecosystem and many species are facing unprecedented threats from disease and habitat alteration. By taking voluntary steps to minimize impacts on our native species, Duke Energy is setting an example of proactive environmental stewardship. We are impressed by their leadership and encourage others in the industry to consider similar actions, “said Jonah Evans, mammalogist with the Texas Parks & Wildlife Department.
About Duke Energy Renewables
Duke Energy Renewables, a nonregulated unit of Duke Energy, operates wind and solar generation facilities across the U.S., with a total electric capacity of 3,000 megawatts. The power is sold to electric utilities, electric cooperatives, municipalities, and commercial and industrial customers. The unit also operates energy storage and microgrid projects. Visit Duke Energy Renewables for more information.
Duke Energy (NYSE: DUK), a Fortune 150 company headquartered in Charlotte, N.C., is one of the largest energy holding companies in the U.S. It employs 30,000 people and has an electric generating capacity of 51,000 megawatts through its regulated utilities, in addition to Duke Energy Renewables’ capacity.
Duke Energy is transforming its customers’ experience, modernizing the energy grid, generating cleaner energy and expanding natural gas infrastructure to create a smarter energy future for the people and communities it serves.
Duke Energy was named to Fortune’s 2019 “World’s Most Admired Companies” list and Forbes’ 2019 “America’s Best Employers” list. More information about the company is available at duke-energy.com. The Duke Energy News Center contains news releases, fact sheets, photos, videos and other materials. Duke Energy’s illumination features stories about people, innovations, community topics and environmental issues. Follow Duke Energy on Twitter, LinkedIn, Instagram and Facebook.
About NRG Systems, Inc.
NRG Systems, Inc., a subsidiary of ESCO Technologies Inc. (NYSE: ESE), revolutionized the way wind resource assessment was done more than 36 years ago. Today, this heritage of innovation drives everything they do. The company is dedicated to designing and manufacturing smart technologies for a more sustainable planet – that means more renewable energy, cleaner air, and a safer environment for all. Their measurement systems, turbine control sensors, Bat Deterrent Systems, and Lidar remote sensors can be found in more than 170 countries. For more information, visit nrgsystems.com.
About Texas State University
Founded in 1899, Texas State University is among the largest universities in Texas with an enrollment of 38,694 students on campuses in San Marcos and Round Rock. Texas State’s 189,000-plus alumni are a powerful force in serving the economic workforce needs of Texas and throughout the world. Designated an Emerging Research University by the State of Texas, Texas State is classified under “Doctoral Universities: Higher Research Activity,” the second-highest designation for research institutions under the Carnegie classification system. For more information, visit txstate.edu.
Jennifer Garber / Duke Energy
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