New Research Could Cut Down on Wind Turbine Bat Deaths

­If you’ve ever dipped your toes in the renewable energy debate, you’ve probably heard that wind turbines have a bad habit of killing wildlife. But Australian research could help eliminate those deaths – at least when it comes to bats.

Estimates for the number of birds killed each year by wind farms vary wildly. From what I can tell, different studies place the figures at 4 to 18 birds killed per turbine per year, with a broad overall appraisal of 140,000 to 679,000 birds killed, annually, though some studies place them in the millions.

Though those figures are a tiny fraction of the birds killed by power lines – 12 to 64 million each year – or cats, they’re not insignificant. And if nothing’s done, turbine bird deaths will continue to rise with the addition of new wind farms and the overall embrace of renewable energy.

In Victoria, Australia, somewhere from 25,000 and 50,000 bats die annually from colliding with the more than 1,400 wind turbines in operation there. And along Australia’s east coast, about 12 bats die each year per turbine.

In relative terms, far more bats than birds are killed by turbines, spurning Australian researchers to action.

And apparently, the solution rests with wind turbine speeds.

According to The Guardian, wind turbines “cut in” (or start turning) at wind speeds of about 3 metres a second (m/s), with maximum output between 10 and 15m/s. And research has found that reducing the cut-in speed from 1 to 3m/s reduced bat deaths by 33% to 81%, while a separate study concluded that a 5m/s cut-in speed reduced bat fatalities by nearly two-thirds.

Obviously, that’s not the final word on turbine-related avian deaths, but it’s a good start.