SENSITIVITY ANALYSIS OF MODELLING PARAMETERS IN WIND TURBINE NOISE ASSESSMENT PROCEDURE

In 2013 the Italian Institute for Environmental Protection and Research (ISPRA), in cooperation with the Environmental Protection Agency of Tuscany Region (ARPAT), published a new methodology for the assessment of noise impact of wind farms. The procedure estimates the emissive and the residual components of noise, also when the residual noise is mainly generated by wind, measured trough measurement campaigns of noise and weather parameters at the receiver for at least 3 weeks. Through iterative steps, the method returns the evaluation of noise impact produced by wind farms, without stopping the farm for measuring the residual noise. The method has been successfully tested through specific measurement campaigns in some Italian sites with different orography conditions, but a proper uncertainty analysis has not been performed yet. Some specific numerical values to be assigned to the parameters for the calculation of noise propagation are involved in the procedure. The paper presents the sensitivity analysis of a key parameter, N-eq, aiming to establish the influence that a variation of a specific input of the procedure has on the final results. This analysis will allow a better understanding of which procedure parameters require more accuracy and will help reducing the uncertainties of the noise impact prediction.