Duke Energy is putting a device that stops wind turbines from killing bats on 255 turbines in Texas

A device stops wind turbines from killing bats

Wind turbines kill bats, and Duke Energy and NRG Systems say a device that emits ultrasound now stops many of those deaths. Duke Energy is installing the device on 255 wind turbines at its Los Vientos wind site in Starr County, Texas, the first time the technology has gone into commercial scale use anywhere in the continental United States.

The field test that found a 50% cut in bat deaths

Duke Energy Renewables, NRG Systems and Texas State University tested the device at 16 turbines at Los Vientos over 2 years, 2017 to 2018. Overall bat deaths at the tested turbines fell 50%. The hoary bat, a species of rising conservation concern, showed the biggest drop, 78%. The Brazilian free tailed bat, the species that made up most of the deaths recorded at the site, fell 55%. A third species in the study, the northern yellow bat, showed no significant reduction, and no source gives that result a percentage.

Our results from this robust, two-year study indicate that NRG's acoustic deterrents significantly reduce Brazilian free-tailed bat and hoary bat fatalities.

Sara Weaver, the researcher who led the field study during her doctoral candidacy at Texas State University, quoted in source 4. Source 4.

Six speakers and a trick borrowed from a moth, stopping turbines from killing bats

The device bolts 6 speakers onto the nacelle, the housing on top of the turbine tower, and needs no new turbine design. It emits continuous ultrasound in the same frequency range that bats use for their own bio sonar, disrupting their ability to navigate and find food near the turbine. The design copies a defense already used in nature, the way a tiger moth confuses the sonar of a hunting bat to escape being eaten. The sound cannot be heard by humans and does not harm bats.

We have to step up and figure out ways to reduce our impacts as bats try to work through all the other challenges they have.

Tim Hayes, environmental development director for commercial renewable sites at Duke Energy, quoted in source 2. Source 2.

A 5 year plan announced in 2019, still underway

Duke Energy and NRG Systems announced the rollout in June 2019, saying installation across all 255 turbines would run over 5 years starting that month. A year later, Duke Energy described the remaining work as the next 4 years. This site reads those 2 dated statements as describing the same finish point, near 2024, from starting months about a year apart, not a change of plan. No source read for this article states that installation across all 255 turbines is finished, so the rollout is described here as announced and underway, not as complete.