Skip to main content
Observer Ethical awards Winners 2011

YouGen Blog

How noisy are wind turbines really?

Posted by Graham Eastwick on 2 November 2009 at 9:50 am

When discussing noise and wind turbines it is important to be clear what size of turbine you are thinking about. The noise from large, commercial wind turbines is very different to that generated by smaller turbines installed at homes, offices and schools. The rotors on smaller turbines rotate much faster.

Data on noise from small wind turbines is often provided by the manufacturers. Ask them for it if it is not in their published data sheet.

As an example the Proven 6 kW wind turbine has the following noise profile published.

– 45 dBA at wind speed of 5 metres per second
– 65 dBA at wind speed 20 metres per second

These noise levels are measured at the turbine itself, and can then be calculated at varying distances from the turbine (noise level falls in proportion to the square of distance).

To give you an idea of how loud this is the following table gives the noise levels for some common situations:

- 30dB – whispering, leaves rustling very gently
- 60dB – normal conversation
- 90dB – in the middle of city traffic
- 120dB – rock concert
- 150dB – jet engine at 10m

The background noise in the local environment is also critical to understanding the impact of noise from any turbine. City centre locations are noisier than rural locations, windy days are noisier than still days. To ensure that noise is not an issue the turbines tend to be sited away from neighbouring properties. Typically 50m to 100m clearance is given from the nearest neighbours.

However, noise perception is also a subjective, psychological phenomenon. If people want to be disturbed by noise they are more likely to hear it and more likely to perceive it as loud. They are also more likely to be disturbed by noise that demands analysis (like conversation or music) than they are by random noise or noise related to wind, birds and similar.

Normal (horizontal axis) wind turbines have potential to generate low levels of noise because some parts of the rotors will be driven faster than the wind, so they create a gentle swish as they cut through the air. This is not true for vertical axis machines, which are silent as they travel at the same speed as the wind.

The only way to really get a feel for how noisy a wind turbine is in operation is to visit one and talk to the owners. A properly maintained and installed wind turbine does not generally cause a noise problem.

Photo by Alan Cleaver

About the Author: Graham Eastwick is a director of Encraft, and manages renewable energy installations for home owners, community organisations and small businesses across the UK.

About the author: Graham Eastwick is a director of Encraft, and manages renewable energy installations for home owners, community organisations and small businesses across the UK.

If you have a question about anything in the above blog, please ask it in the comments section below.

Like this blog? Keep up to date with our free monthly newsletter

Comments

2 comments - read them below or add one

Cathy Debenham

Cathy DebenhamComment left on: 4 November 2009 at 3:52 pm

Ooh, it's a fascinating subject. One of the things I wonder is whether it's a matter of frequency for example I hear the fan in the above example, and the beeps my car makes if you leave the headlights on, and my husband doesn't. Does hearing differ, so some people hear things and others don't. Or is it just psychological? I certainly didn't want to hear the former, but it's quite useful to hear the beeps.

report abuse

nigelpensarn

nigelpensarnComment left on: 4 November 2009 at 3:37 pm

I read with interest your blog on noise. I have a 6KW Proven installed 6 months ago and live 200m from the turbine. I find there is virtually no noise from it unless your are directly downwind. It is then only noticeable if you are out side and the wind is above 30mph and yet my neighbour who is also 200m away has complained bitterly, involving the council and our MP. Is this an example of subjectivity over noise levels or an extreem case of nimbyism? I am pleased to say the council and MP are turning a deaf ear to him!

report abuse

Leave a comment

You must log in to make a comment. If you haven't already registered, please sign up as a company or an individual, then come back and have your say.