Ways to a further prevention of wind turbine noise disturbance: the extent to which the current sound assessment methods are satisfactory in noise estimation and possible improvements
Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
This text reviews the topic on how improved understanding and assessment of noise from wind turbines can and should mitigate noise disturbance for neighbouring inhabitants.
Experienced noise disturbance can lead to all kinds of problems for inhabitants, but also for wind power development in general: public attitude can turn negative, there can be claims, law suits and a reluctance of local authorities to welcome further wind power development.
There are various disturbing sound effects that wind turbines can cause for neighbouring inhabitants. These effects include swishing sound, pulsing sound, amplitude modulation, whistling sound but also low frequency sound.
Assessment methods obviously should try to assess or signal these effects properly to prevent disturbance. The IEC standards are widely accepted as guidance for sound measurements. It covers the apparent sound pressure level, tonality and octave bands. A critic is that amplitude modulation is not covered well, also because it is hard to measure. But this sound effect, that comes and goes often quickly, are an important nuisance.
The circumstances in the area around a wind turbine play an important role in the propagation of the sound that is emitted to the immission point. The nocturnal stable boundary layer, the topographical elevation of wind turbines, downhill propagation and the siting of wind turbines in forest area are all examples of situations that enhance the propagation of sound.
But IEC standards do not allow measurements at favourable conditions, since there is always the requirement to measure downwind in a situation with 8 meter per second wind speed at 10 meters high. This is not always representative for a situation in which neighbouring inhabitants suffer from wind turbine noise.
Inadequate legislation can enforce assessment practices that are incompatible in preventing real sound disturbance for neighbours. To prevent this, legislation and requirements set by responsible governments may have to be reviewed. If that happens requirements that are issued on calculation and measurements become more suitable to prevent sound disturbance from happening. But the intrinsic character of wind turbine noise as well as the meteorological environment at the specific site should be approached more accurately.
Place, publisher, year, edition, pages
2013. , 75 p.
IdentifiersURN: urn:nbn:se:uu:diva-206613OAI: oai:DiVA.org:uu-206613DiVA: diva2:644776
Master Program in Wind Power Project Management, 60 hp (HGO)
Aldén, Liselotte, Junior Lecturer
Sørensen, Jens Nørkær, Professor