From devastating outbreaks of white nose syndrome to large numbers of bat deaths caused by collision and dramatic changes in air pressure, the health of bat populations has emerged as a major issue for wind farm developers and operators. And while a range of solutions including specialized radar systems and purple wind turbines have been proposed and tested, there has been a gap in research and technology that helps predict the movements of migratory bats.
But now, researchers at the US Forest Service have developed a new technology and predictive tool designed to help wind farm operators reduce impacts on migratory bats while maximizing energy production. The interactive tool, created by ecologist Ted Weller and statistician Jim Baldwin from the USDA Forest Service's Pacific Southwest Research Station, allows users to predict the probability of bat presence (See a demonstration of the interactive tool at the Wolfram Demonstrations Project website).
In research conducted at Dillon Wind Energy Facility in the San Gorgonio Pass Wind Resource Area in Southern California (pdf), Weller and his team used devices that detected the bats’ echolocation calls, and then linked the presence of bats to the on-site weather conditions.
"Increasing the wind speed at which turbines begin to spin and produce energy to the grid has proven to be an effective way to reduce bat fatalities; however, bat activity levels depend on more than just wind speed," says ecologist Weller. “Our work demonstrates the use of a decision-making tool that could protect bats when fatality risk is highest while maximizing energy production on nights with a low chance of fatalities.”
The researchers also found that multiple, properly-deployed echolocation detectors better characterize bat activity at the facility.
“These days, pre-construction echolocation monitoring is as common as meteorological monitoring at wind energy facilities," Weller explains, "so the basic building blocks for these models are available at most proposed sites.”
Funded by the California Energy Commission Public Interest Energy Research program, the study was a collaborative effort between the USDA, Iberdrola Renewables, and the Bats and Wind Energy Cooperative.