Hochradel K, Adomeit U, Mages J, Simon R, Stiller F, Behr O (2015)
Publication Language: English
Publication Type: Conference contribution
Publication year: 2015
Event location: Berlin
Attraction of bats to wind turbines is frequently discussed to be one of the reasons for high fatality rates. Thus, knowledge on activity distribution is vital to improve methods to reduce fatalities. However, no research has yet been conducted on the influence of existing wind turbines on the behavior of bats. We have seen different approaches to reduce fatalities such as ultrasonic deterrents or ‘bat-friendly’ operational algorithms, most of which share the assumption of an equally distributed bat activity in the rotor swept area. We quantified bat activity at wind turbines as a function of distance to the nacelle with a stereo thermal camera system. Stereo images were recorded in 2008 and 2012 during ten nights at six turbines at four sites in Germany. The turbines were also equipped with at least one acoustic bat detector installed in the nacelle. We triangulated the position of each recorded bat in absolute coordinates with the nacelle of the wind turbine as origin and the rotor diameter as field of view and correlated the results with the acoustic records. Activity decreased exponentially with increasing distance to the nacelle and converged to a constant level. This level describes the normal distribution of bats in free air space without the influence of wind turbines. Bat activity in close proximity (<10m) could not be determined since the nacelle covers most of the field of view. The distribution of bats was based on a total amount of 4468 triangulated bat positions. We used the distribution of bats triangulated around the nacelle to calculate a novel scaling factor accounting for varying rotor diameters of wind turbines that can be used for calculating ‘bat-friendly’ operational algorithms. As of yet, scaling was based on the assumption that bat activity is equally distributed. When using a uniform distribution, the scaled activity is largely overestimated which reduces the efficiency of the operational algorithms. The relation between bat activity and distance to the nacelle not only enabled us to improve the scaling for operational algorithms but also suggests that bats are attracted to wind turbines.
APA:
Hochradel, K., Adomeit, U., Mages, J., Simon, R., Stiller, F., & Behr, O. (2015). Bats are attracted to wind turbines – determining the distribution of bats by a stereo thermal camera system. In Proceedings of the Conference on Wind energy an Wildlife Impacts. Berlin.
MLA:
Hochradel, Klaus, et al. "Bats are attracted to wind turbines – determining the distribution of bats by a stereo thermal camera system." Proceedings of the Conference on Wind energy an Wildlife Impacts, Berlin 2015.
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