Wind Energy Planning

Whenever we talk about noise we often think of unwanted sound for example vehicles, factories, snorers and all those other anti-social forms that we have to share our world with. We rarely refer to the waves in the sea or a babbling brook as noise but as “natural sounds”.

Whether it is human made or naturally occurring, virtually everything that moves will result in some sound. Wind turning the blades of wind turbines results in sound just as the wind moving the leaves in trees. Modern wind turbines are however generally quiet in operation, and compared to the noise of road traffic, trains and aircraft, the noise from wind turbines is very low.

There are guidelines in place for any new land use, with the aim of protecting the quality of life for nearby residents. In the UK a document entitled “Assessment and Rating of Noise From Wind Farms, ETSU R’97” (published in 1997) sets out guidelines which wind farm companies are required to demonstrate they can comply with. Noise from wind turbines will not be allowed to exceed a specified limit which is usually no more than 5dB (A) above the prevailing background noise existing prior to the construction of the wind farm.

Companies in the wind turbine industry are often asked how noisy wind turbines are. The companies then try to describe it, for example the British Wind Energy Association web site states that “Outside the nearest houses, which are at least 300 metres away, and more often further, the sound of a wind turbine generating electricity is likely to be about the same level as noise from a flowing stream about 50-100 metres away or the noise of leaves rustling in a gentle breeze. This is similar to the sound level inside a typical living room with a gas fire switched on.” I have always found these comparisons rather unsatisfying – what is a “typical living room”? Wind farm recordings usually result in you listening to microphone or speaker noise rather the wind farm and the listener is not in context.

The only way to find out what a wind turbine sounds like is to visit one in person. There is a map of UK wind energy projects on the British Wind Energy Association Web-site – so please go and visit one if you really want to find out – before you offer up an opinion.