Wind energy has proven itself an emission-free energy source, but bat and bird collisions with wind turbines result in thousands of fatalities every year. Bats are a valuable resource in the ecosystem, providing pest management, pollination, and plant seed dispersal.
A new study in Frontiers in Ecology and the Environment has revealed some interesting conclusions regarding wind turbine speed and bat mortality rates.
Most wind turbines in the USA are programmed to begin rotating at 8 to 9 mph, but researchers have found that raising the cut-in speed (the wind speed at which turbines begin generating electricity to the power grid) to 11 mph reduces mortality rates for a very low comparative energy loss.
For a 1% annual energy loss, a 44-93% reduction in bat fatalities was achieved.
Edward Arnett from Bat Conservation International in Austin, TX., says "This is the only proven mitigation option to reduce bat kills at this time. If we want to pursue the benefits associated with wind energy, we need to consider the local ecological impacts that the turbines could cause. We have already seen a rise in bat mortality associated with wind energy development, but our study shows that, by marginally limiting the turbines during the summer and fall months, we can save bats as well as promote advances in alternative energy."
Emission-free energy such as the wind turbine is sometimes considered without realizing other potential ecosystem health dangers, and with just a small reduction energy generation, migratory bats will continue to bestow valuable ecological benefits.