1,000s Of Bats Die Every Year From Wind Turbines: Can We Save Them?
The answer is “Yes”: it’s possible that new technology could save the bats.
Care2 has noted previously that communication towers kill nearly 7 million birds every year as they cross the Americas, migrating south, and that wind turbines with retractable blades could cut down on the number of birds killed by these turbines.
But what about the thousands of bats killed by wind turbines?
Dead bats are turning up beneath wind turbines all over the world. Bat fatalities have now been documented at nearly every wind facility in North America where adequate surveys for bats have been conducted, and several of these sites are estimated to cause the deaths of thousands of bats per year.
The mystery of why bats die at turbine sites remains unsolved. Is it a simple case of flying in the wrong place at the wrong time? Are bats attracted to the spinning turbine blades? Why are so many bats colliding with turbines compared to their infrequent crashes with other tall, human-made structures?
To work on this problem, engineers and bat biologists are coming together this summer at a wind farm in Wisconsin to field-test a potential fix. They’ll attach ultrasonic microphones to four or five turbine nacelles to record the high-pitched squeaks and clicks bats emit for navigating and locating prey.
Based on the data collected there and at 40 other wind installations, software developers will create a predictive model that also factors in meteorological information like wind speed, temperature, and precipitation. The model will yield a probability score that indicates the risk to bats at the site at any given time. When the risk is high—meaning there are likely many bats present—the utility operator will be able to shut down the turbines and then bring them back up when the risk is low.
“This project is really focused on trying to reduce bat mortality at wind farms while at the same times maximizing electricity production,” says John Goodrich-Mahoney, a senior project manager at the Electric Power Research Institute (EPRI), the sponsor of the field test, which runs through next year. “How do you balance those two needs?”
The economic impact of losing so many insect-eating animals is staggering: A study published in Science last year estimated that bat deaths could lead to annual agricultural losses in North America of more than US $3.7 billion.
It was in 2003, as biologists searching for dead birds at a wind farm in West Virginia noticed hundreds of dead bats, that wind turbines’ deadly impact on bats came to light. Scientists concluded that 1400 to 4000 bats were being killed there each year.
Since then, dozens of studies throughout North America and Europe have confirmed and refined the finding. It seems that most bats are killed when the turbine blade strikes them, but some may also succumb to the rapid pressure change they experience close to the turbine, which causes their hearts and lungs to burst.
Other options have been proposed to solve the problem: several years ago, a project sponsored by Bat Conservation International looked at whether ultrasonic “Boom boxes” mounted on wind turbines could deter bats. Another study, by Barry Nicholls and Paul Racey at Aberdeen University in Scotland, considered radar as a bat deterrent.
But this one looks the most promising. Let’s hope that the engineers and bat biologists in Wisconsin will be successful.
Photo Credit: Sammy & Johnny