From Green Right Now Reports

Bird and bat deaths from wind farms have been among the few environmental negatives of this growing source of alternative energy. But a new study offers hope that a solution can be found.

A new study of the interaction between bats and wind turbines at the Casselman Wind Power Project found that turning off the turbines during low wind periods reduced bat mortality by more than 70 percent.

Iberdrola Renewables, owner of the Casselman wind farm in southwestern Pennsylvania, partnered with independent conservation group Bat Conservation International (BCI) to collect the data. From late July to mid-October 2008, Iberdrola Renewables and 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.

“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,” Andy Linehan, wind permitting director for Iberdrola Renewables, said in a statement. He said Iberdrola Renewables “looks forward to a second year of the study to confirm what appears to be very good results with modest (power) generation lost.”

The research is being conducted as part of the Bats and Wind Energy Cooperative (BWEC), a coalition of the American Wind Energy Association, 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. This study is one of a series of collaborations with BWEC at five Iberdrola Renewables sites.

Although it was crucial for this study, Iberdrola Renewables cautioned that curtailing turbine operations is not likely to be the complete solution to reducing the impact on bats in all circumstances or locations. But the company believes it may be a practical solution at some northeastern U.S. sites where elevated bat mortality has been a particular concern, company officials said.

Dr. Ed Arnett, conservation scientist at BCI and program coordinator for the BWEC, led a team of scientists that tested increasing the minimum wind speed necessary for turbines to begin spinning and producing electricity into the power grid.

“We hypothesized that bat fatalities could be lowered substantially by reducing the amount of turbine operating hours during low wind periods when bats are most active. We found that bat kills were reduced from 53 to 87 percent on any given night at turbines that were partially curtailed during low wind nights compared to those that were fully operational,” Arnett said in a statement.

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