At utility-scale wind energy facilities, blanket curtailment of turbines in response to wind speed minimizes bat fatalities, but sacrifices generation and revenue by remaining in effect even when bats are absent. We Energies, EPRI, and its member companies funded a study to develop a turbine curtailment approach that minimizes such economic costs while ensuring lower fatality rates for bats. Turbine-Integrated Mortality Reduction (TIMRSM) is a Smart Curtailment hardware and software system that runs real-time bat activity and weather data in predictive models that link these parameters to bat mortality and issue a current risk value (red/curtail, green/resume, or yellow/override) used to drive turbine operation. Because the TIMR system does not curtail when bats are absent, it frees up turbine operating time for generation.
We Energies chose to implement a predictive model based on descriptive statistical cost–benefit analysis at its Wisconsin Blue Sky Green Field (BSGF) wind energy facility in 2015. During fall bat migration, 10 turbines were operated normally and 10 were model-operated with a 30-minute curtailment period. Real-time data for the study were supplied by acoustic monitoring of bat activity (calls) and wind speed recordings at the turbine nacelle. Bat carcass counts for three species and the Myotis family provided evidence of bat mortality. Study results showed a strong correlation between bat activity and mortality, validating the use of activity data to drive curtailment. This is the first study to demonstrate a reduction in mortality for any Myotis species; some members of this family are endangered. The study presents an economic analysis of generation and revenue under Smart Curtailment at BSGF, as well as other factors affecting facility operations.
TIMR could be implemented at a new site in weeks, since there is no need to reprogram the core Supervisory Control and Data Acquisition (SCADA) and the communication and alerting interface with SCADA is readily transferred to new users with minimal customization.