Reducing bat mortality at wind farms using site-specific mitigation measures: A case study in the Mediterranean region, Croatia

Abstract

A 4-year monitoring of bat fauna at Rudine wind farm in Croatia aimed to produce mitigation measures to minimize both the number of bat fatalities and power loss in energy production. During the first 2 years, a high number of carcasses was found from mid-July to the end of October, indicating the need for some mitigation strategy. Based on the results of carcass searches, meteorological data and bat activity monitored at a weather mast and four wind turbine nacelles, mitigation measures were proposed. During the next 2 years, wind turbine curtailment was implemented in the high collision risk period based on critical wind speed thresholds varying from 5.0 to 6.5 ms-1. Estimation of a total number of bat fatalities was conducted with the GenEst software for each monitoring year. A 78% reduction in estimated number of fatalities was recorded indicating the effectiveness of implemented measures.