Perceived Noise Impact of Transitioning Towards Larger Wind Turbines Using Auralisations

The human perception of two wind turbines of different sizes, a small NTK turbine and a larger NREL model, was evaluated through their synthetically auralised sound. A wide range of wind speed conditions and observer locations was considered. The simulated sounds were analyzed using equivalent sound pressure levels and psychoacoustic sound quality metrics. Moreover, listening experiments were conducted to evaluate the human response to the same sounds. The least-squares models fitted to the results provided scaling laws for the different sound metrics as a function of wind speed (divided into low- and high-speed regimes) and distance to the observer. At lower wind speeds, the NREL turbine’s noise and annoyance levels increase faster with increasing wind speed than the NTK turbine. The results of the NREL turbine at high wind speeds seem to indicate that turbulent boundary layer trailing-edge noise contributes more to annoyance than leading edge turbulent inflow noise. In the listening experiments, the larger wind turbine was perceived roughly 30% more annoying than the smaller one for the same conditions. The equivalent A-weighted sound pressure level and the psychoacoustic annoyance model by Zwicker were reported to closely represent the annoyance ratings reported in the listening experiment.