Forthbank Wind Energy Development - Partnerships for Renewables

Forthbank Wind Energy Development
Table 8.15 13 Riverside View Predicted Wind Farm Noise Immission Levels, ETSU-R-97
Day-time and Night-time Limits Derived from 12 Riverside View, and the Associated
Immission and Limit Margins (negative margins indicate the immission level is below the
limit). All levels L A90,T
Description
Wind Speed at 10m Height, m/s
3 4 5 6 7 8 9 10 11 12
Predicted noise 29.8 33.8 37.3 40.3 41.3 41.8 41.8 41.8 41.8 41.8
Day-time limit 40.6 42.3 43.9 45.2 46.3 46.9 46.9 46.9 46.9 46.9
Night-time limit 43.0 43.0 43.0 43.0 43.0 43.0 43.0 43.0 43.0 43.0
Day-time limit margin -10.8 -8.5 -6.6 -5.0 -5.0 -5.1 -5.1 -5.1 -5.1 -5.1
Night-time limit margin -13.2 -9.2 -5.7 -2.7 -1.7 -1.2 -1.2 -1.2 -1.2 -1.2
8.7.5 The ETSU-R-97 fixed part of the limit during the day time should lie within the range from 35
dB(A) to 40 dB(A). The factors to be used to determine where in this range have been
discussed above. Although the area is generally of a rural character, all dwellings were found
to be of a relatively exposed character, with background noise levels clearly increasing with
wind speeds. Furthermore, there would be relatively little number of properties affected by
noise. However, given the relative scale of the development and the limited effect that having
a limit at the lower end of this range would have on the number of turbines installed, it is
considered appropriate to set the limit at the lower end of the range.
Low Frequency Noise and Vibration
8.7.6 Low frequency noise and vibration resulting from the operation of wind farms, together with
the often associated subject of blade swish, are all issues that have been attracting an
increasing amount of attention over recent years. Consequently Appendix 8.1 includes a
detailed discussion of these topics. In summary of the information provided therein, the
current recommendation is that ETSU-R-97 should continue to be used in its present form for
the assessment and rating of operational noise from wind farms.
Evaluation of Effects
Table 8.16 Summary Table of Effects
Potential Effect
Construction Noise
Operational Noise
8.8 Monitoring
Evaluation of Effect
Noise levels have been predicted using the methodology set out in BS 5228-1. Based on
effect assessment criteria derived and supported by a range of noise policy and guidance,
the overall effect of construction noise is considered to represent a negligible to minor effect.
Noise criteria have been established in accordance with ETSU-R-97. It has also been
shown that these criteria are achievable with a commercially available turbine suitable for the
site. The basis of the ETSU-R-97 method is to define acceptable noise limits thought to offer
reasonable protection to residents in areas around wind farm developments. Operational
noise immission levels are acceptable in terms of the guidance commended by planning
policy for the assessment of wind farm noise, and therefore considered not significant in EIA
terms.
8.8.1 It is proposed that if planning consent is granted for the proposed wind energy development,
conditions attached to the planning consent should include the requirement that, in the event
of a noise complaint, noise levels resulting from the operation of the proposed wind energy
development are measured in order to demonstrate compliance with the conditioned noise
limits. Such monitoring should be done in full accordance with ETSU-R-97 and include
penalties for any tonal characteristics of the noise.
November 2010 Chapter 8 Page 19
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