Wind turbine noise measurements and abatement methods - Wind Power Generation and Wind Turbine Design - page 658

emissions, forces them to make extensive use in their future environmental plans
to install as many wind turbine as necessary. It becomes apparent that a number of
improvements in standards and regulations is needed to ensure that communities
can reliably anticipate noise from wind turbines and to ensure that the data are
available to make those sound estimations.
Also research and development in establishing commonly used standards
is essential for manufactures and planners to be able to conduct accurate
measurements.
We have already mentioned in this chapter that the challenge in measuring noise
from wind turbines is that the background noise levels increase as the wind speed
increases making it diffi cult to accurately measure sound levels from the turbines.
It is therefore essential that more investigation is being carried out into measuring
background noise as a function of both time of day and wind speed and also taking
into consideration the factors that affect propagation such as refl ection and absorp-
tion, ground topology and weather phenomena. This further research would help
in establishing accurate and practical noise standards that consequently would
inform and guide manufacturers and installers to make comprehensive sound
power level measurements, based on new standards, available to the public.
Standards are also needed for the measurement of noise from small wind tur-
bines. These should encounter not only for noise but also for vibration effects
since this seems to be a major problem for house mounted wind turbines. These
would also inform planners and installers on their decision to select type of wind
turbine, location as well as hours of operation.

R eferences

[1] Wagner, S., Bareis, R. & Guidati, G., Wind Turbine Noise , Springer-Verlag:
Berlin, 1996.
[2] Rogers, L.A., Manwell, F.J. & Wright, S., Wind Turbine Acoustic Noise ,
Renewable Energy Research Laboratory, 2006.
[3] Junger, C. Miguel & Feit David, Sound, Structures and their Interaction ,
Acoustical Society of America, 1993.
[4] Morse, P.M. & Ingard, K.U., Theoretical Acoustics , McGraw-Hill: New York,
1968.
[5] Pierce, D. Allan, Acoustics: An Introduction to Its Physical Principles and
Applications , Acoustical Society of America, 1989.
[ 6] Dowling, P.A. & Ffowcs Williams, E.J., Sound and Sources of Sound , Ellis
Horwood, 1983.
[ 7] Beranek, L.L. & Ver, I.L., Noise and Vibration Control Engineering:
Principles and. Applications , Wiley: New York, 1992.
[ 8] Planning

Policy Guidance Note 24 'Planning and Noise' (PPG24),

Department of the Environment, 1994.
[9] Bruel and Kjaer Instruments, http://www.bkhome.com/
[10] Harris, C., Absorption of sound in air versus humidity and temperature.
Journal of the Acoustical Society of America , 40 , p. 148, 1966.