The first year of an effort to study the interaction between bats and wind turbines at the Casselman Wind Power Project shows that turning off the turbines during low wind periods reduced bat mortality by more than 70%.
Iberdrola Renewables, the owner of the Casselman wind farm, partnered with independent conservation group Bat Conservation International (BCI) for wildlife data collection at the southwestern Pennsylvania wind power project.
BCI's work is being conducted through the Bats and Wind Energy Cooperative (BWEC), which is a coalition of the American Wind Energy Association (AWEA), the U.S. Fish and Wildlife Service, the National Renewable Energy Laboratory and BCI. The cooperative's work focuses on identifying and addressing potential wind energy impacts on bats.
‘Shutting down turbines at certain wind speeds during periods when bats appear most vulnerable at this northeastern U.S. wind farm may have the potential to be a cost-effective way to reduce the impact on bats during their late summer migration season,’ says Andy Linehan, wind permitting director for Iberdrola Renewables.
From late July to mid-October 2008, Iberdrola Renewables, working with BCI researchers, conducted a controlled experiment in which selected wind turbines at the Casselman project were stopped during relatively low-wind-speed nights in the late summer and early fall. This represents the first U.S.-based effort reporting the effects of shutting down turbines on reducing bat deaths.
Although it was crucial for this study, curtailing turbine operations is not likely to be the complete solution to reducing the impact on bats in all circumstances or locations, but it may be a practical solution at some northeastern U.S. sites where elevated bat mortality has been a concern, company officials say. This study is one of a series of collaborations with BWEC at five Iberdrola Renewables sites.
The results of the 2008 Casselman study were reviewed by BWEC's scientific advisory committee before being made public.
SOURCE: Iberdrola Renewables