Effectiveness of an operational mitigation experiment to reduce bat fatalities at the Pinnacle Wind Farm, Mineral County, West Virginia, 2012

Published source details Hein C.D., Prichard A., Mabee T. & Schirmacher M.R. (2013) Effectiveness of an operational mitigation experiment to reduce bat fatalities at the Pinnacle Wind Farm, Mineral County, West Virginia, 2012. Bat Conservation International report.
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This study is summarised as evidence for the following.

	Action	Category
	Increase the wind speed at which turbines become operational (‘cut-in speed’) Action Link

Increase the wind speed at which turbines become operational (‘cut-in speed’)

A replicated, randomized, controlled study in 2012 at a wind farm in a forested area of West Virginia, USA (Hein et al 2013; same site as Hein et al 2014) found that increasing the wind speed at which turbines become operational (‘cut-in speed’) for all or part of the night did not result in fewer bat fatalities than at conventional turbines. Overall, average nightly bat fatality rates did not differ significantly between turbines with the cut-in speed increased to 5 m/s for all or part of the night and conventional control turbines (data reported as statistical model results). The authors report that wind speeds of 3–5 m/s (i.e. when the treatments were in effect) only occurred for 17% of the time during the study. Six species were found across the site (see original report for details). Each of 12 turbines was randomly assigned to one of two treatments (cut-in speed increased to 5 m/s from sunset to sunrise or for the first 4 h after sunset) or as a control (conventional cut-in speed of 3 m/s). Treatments were rotated between turbines nightly over 75 nights in July–September 2012. All 12 turbines were prevented from turning (‘feathered’) below the cut-in speed. Daily carcass searches were conducted along transects in plots (126 x 120 m) centred on each of the 12 turbines.

(Summarised by: Anna Berthinussen)