A study performed by Edward Arnett, from Bat Conservation International in Austing, TX, and his colleagues, have determined that wind turbine operators could lower bat deaths by as much as 93 percent and at least 44 percent by raising the wind speed threshold at which the turbines begin to spin.
Killing bats impacts the ecosystems both locally and nationwide, because they offer a natural way of killing pest, and help with pollination and dispersal of various plant seeds. The test has been made during 25 summer and fall nights, during their peak periods of migration. These periods coincided with the highest bat fatality rate.
Wind turbines are generally programmed to begin spinning when wind speed reaches 8 to 9 mph (also known as the cut-in speed). The researchers raised this speed to 11 mph, so the turbines spun more rarely than those programmed to open at 8 to 9 mph.
The 11 mph speed caused the turbines to kill a significantly lower number of bats, and offered a win-win situation: the annual power loss was under one percent. Moreover, taking into account that the change has been made during the months when wind speeds are naturally lower, the overall estimated energy loss is marginal.
We have also been mentioning how to keep bats from hitting the wind turbines’ blades in a previous article, by painting the turbine in purple, so it does not attract the bugs that the bats are after.
“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.”