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Providing evidence to improve practice

Individual study: Reducing bat fatalities at wind facilities while improving the economic efficiency of operational mitigation

Published source details

Martin C.M., Arnett E.B., Stevens R.D. & Wallace M. (2017) Reducing bat fatalities at wind facilities while improving the economic efficiency of operational mitigation. Journal of Mammalogy, 98, 378-385


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Increase the wind speed at which turbines become operational (‘cut-in speed’) to reduce bat fatalities Bat Conservation

A randomized, replicated, controlled study in 2012–2013 at a wind farm in Vermont USA (Martin et al 2017) found that increasing the wind speed at which turbines become operational (‘cut-in speed’) at temperatures above 9.5°C resulted in fewer bat fatalities than at turbines with conventional cut-in speeds. The number of bat fatalities was 62% lower at wind turbines with increased cut-in speeds (average 0.5 bats/turbine) than at fully operational turbines (1.4 bats/turbine). At treatment turbines, cut-in wind speeds were increased to 6 m/s when temperatures were >9.5°C. Fully operational control turbines had a cut-in wind speed of 4 m/s. In each year, eight of 16 turbines were randomly assigned the treatment for 60 nights. Daily fatality searches were carried out in June–September 2012 and 2013. Rectangular study plots around each turbine were searched using transects spaced 6 m apart. If applied to all turbines, it was estimated that the operational changes would result in annual energy losses of 1%.

(Summarised by Anna Berthinussen)