Bat deaths at wind farms not due to collisions

Scientific American reports that an examination of 188 bats killed at a wind farm in Southwestern Alberta last summer shows the creatures did not meet their end by smashing into the giant blades as one might expect. Rather 90% of the bats were killed by blood vessels in their lungs bursting due to changes in wind pressure.
The report explains that as wind moves through a wind turbine’s blades, the pressure behind the blades drops by five to 10 kilopascals. Any bat entering the zone with a lungful of air, suddenly finds its lungs rapidly expanding and bursting.
The report by David Biello in Scientific American was based on research by Erin Baerwald of the University of Calgary.
Baerwald studied the Summerview wind farm, where hundreds of bats are killed every year, mostly during the fall migration period.
But it is only since the new, taller turbines have been added to the wind farm that bat casualties began to rise. The Scientific American article quoted Baerwald as saying: “As turbine height increases, bat deaths increase exponentially. What we found is a lot of internal hemorrhaging.”
Experts don’t have any answers yet as to what measures can be taken to protect the bats, except stopping turbines from spinning during the times when bats are most active.
The study in Alberta was funded by wind power developers including Enmax, Suncor Energy and TransAlta Wind, along with a Texas-based organization known as Bat Conservation International.
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