I thought wind turbines were silent. How can they have the potential to cause noise pollution?
There are two main types of noise from industrial wind turbines the noise of the mechanical gearing in the equipment compartment, and the noise the blades make when they pass through the air. Recent turbine design has limited the noise of the gearing mechanisms, and the main issue with recent problem developments has been the noise created by the movement of the blades. Whilst they can look deceptively slow from a distance, on a 130m turbine there is a 50m blade going round at around 15 revolutions per minute. This leads to blade tip speeds in excess of 150mph, and it is the movement of the blade through the air, and especially when the blades pass the tower, that causes noise. Complaints at problem sites are that noise from the blades is especially prominent at night, where it may even be calm at ground level with the turbine still rotating at the 80m height causing blade induced air turbulence and noise. Noise is also worse downwind of the turbines, and with a south to south westerly
