Scientists at the University of Calgary (U of C) have found a way to reduce bat deaths from wind turbines by up to 60%, without significantly reducing the energy generated from the wind farm. The research, recently published in the Journal of Wildlife Management, demonstrates that slowing turbine blades to near motionless in low-wind periods significantly reduces bat mortality.
‘Biologically, this makes sense, as bats are more likely to fly when wind speeds are relatively low,’ says U of C biology professor Robert Barclay, who co-authored the paper with student Erin Baerwald, and Jason Edworthy and Matt Holder of TransAlta Corp. ‘When it's really windy, which is when the turbines are reaping the most energy, bats don't like to fly. There is a potential for biology and economics to mesh nicely.’
Over the one-month experiment, total revenue lost from the 15 wind turbines was estimated between C$3,000 and C$4,000. TransAlta has applied the low wind mitigation strategy to the 38 turbines identified in the study area.
Last year, a Barclay-Baerwald study shed new light on the reasons for bat deaths under wind turbines in the Pincher Creek area. Researchers found that the majority of migratory bats in this southern Alberta location were killed because a sudden drop of air pressure near the blades caused injuries to the bats' lungs – an occurrence known as barotrauma.
The next step was to find a way to mitigate the deaths. TransAlta initiated a follow-up study at the same site to determine what could be done.
SOURCE: University of Calgary
