Since 2006, Bat Conservation International (BCI), under the auspices of the Bats and Wind Energy Cooperative (BWEC) has been investigating the effects of ultrasonic acoustic deterrents (UADs) to reduce bat fatalities at wind turbines. Arnett et al. (2013) published the first study testing this type of technology at an operational wind energy facility. Despite multiple failures in the devices, associated with water entry and overheating, the results showed an 18–62% reduction in overall bat fatalities. Fatalities for hoary bats and silver-haired bats were 2 to 4 times higher at control turbines relative to deterrent-equipped turbines. Despite the promising, yet somewhat equivocal results due to equipment issues, limited funds were available to advance the technology and conduct further experimental studies. Deterrent technology may offer a potentially mutually beneficial strategy to reduce bat fatalities at wind energy facilities while allowing for the normal operation of wind turbines, yet the technology requires further refinement and field testing to confirm its effectiveness as an impact reduction strategy.
The Wind Energy Technologies Office of U.S. Department of Energy-Energy Efficiency and Renewable Energy (DOE/EERE) is interested in measures to mitigate (avoid, minimize or compensate for) the potential impacts of wind energy development on bat species. The ‘Bat Impact Minimization Technologies and Field Testing Opportunities’ Award is designed to advance the commercial readiness of bat impact minimization technologies to provide wind stakeholders with tools to minimize the wildlife impacts, and regulatory and financial risks. This study is 1 of 5 awards provided by the DOE/EERE in 2015.
The overall project objective is to assess the effectiveness of an ultrasonic acoustic deterrent device to reduce bat activity and mortality at wind turbines.
The major project goals are to 1) determine the best placement and orientation of the ultrasonic acoustic deterrents to ensure safety, compatibility and functionality of the devices, 2) assess the functionality of a newly redesigned ultrasonic acoustic deterrent, 3) given the specific placement and orientation of the ultrasonic acoustic deterrent, investigate the effectiveness of the deterrent in reducing bat mortality at wind turbines, and 4) directly compare the costs and benefits of ultrasonic acoustic deterrents to operational minimization (i.e., feathering blades and raising cut-in speeds of wind turbines to reduce bat mortality).