Bat-curtailment practices…

Bat-curtailment practices are nuanced and rely on precise and clear language to achieve intended outcomes. Therefore, we suggest that guidance more clearly reference industry standard language on curtailment, cut-in speeds, and minimization techniques. This includes:
• Clarify that raising the cut-in speed includes feathering of blades below cut-in to prevent rotation of the blade.
o This clarification is not made in the first mention of raising the cut-in speed and only marginally mentioned in one reference.
o Please refer to page 51 in Whitby et. al. 2021 for standard definitions used since 2014 .
• Remove references to ‘smart curtailment’. This is not a clear term and often means different things to each reader. The standard in the industry and research communities is Acoustic-triggered curtailment (for curtailment that uses near real-time bat activity information from acoustics) and predictive curtailment (for algorithms that predict bat activity levels based on meteorological factors). These techniques can be combined, for example acoustic-triggered curtailment can be implemented only under specific conditions determined by a predictive algorithm.

In order to ensure that fatality reduction outcomes are met, we suggest that the Ontario guidelines include targets for fatality and/or acoustic exposure reductions (e.g., 50% fatality reduction) for all methods, especially site-specific approaches.

Finally, we suggest that Ontario include a universal minimization strategy for all facilities that limit blade rotation when not generating electricity. This includes periods below manufactures cut-in speeds when electricity is not being generated. This minimization technique is often referred to by the ambiguous name of ‘feathering’, which originates from the method of implementation which is to rotate the blades (or feather) perpendicular to the wind so that blades rotate at less than 1 RPM.