Download Submission on the proposed revisions to the Wind Energy

Tim Stuart
00 353 (0)XXXXXX
XXXXXXX, Co. Meath, Ireland.
XXXXXXXnet
Friday, 21 February 2014
Wind Submissions,
Planning Section,
Department of the Environment, Community and Local Government, Custom House, Dublin 1.
Email: [email protected]
Submission on the proposed revisions to the Wind Energy Development
Guidelines
Noise
There are a number of perspectives on noise.
There is the Physical Vibration in the medium that conveys noise. This is very amenable to
scientific investigation. Scientific analysis of the physical vibration focuses on two particular aspects
of noise: amplitude or intensity, measured in decibels (Db), and frequency measured in cycles per
second (Hz).
There is the Stimulations within the Ear to the physical vibration. There are hairs attached to hair
cells in the ear that vibrate in sympathy with the frequency of the physical vibrations and with an
amplitude that is a function of the amplitude and frequency of the physical vibration. There are two
distinct sets of hair cells, inner and outer, that respond in different ways to different frequencies, the
outer hair cells being more responsive to lower frequencies including infrasound frequencies. The
motion of these hairs excite their adjacent nerves cells (approximately 25,000 of them) that send
signals to the brain.
Research on animals and the comparison of the anatomy of the ears of these animals with the ears of
humans result in a reasonable understanding of the stimulations within the ear. However, ethical
considerations limit scientific experiments on the human ear and difficulties with definition, control
and non-linearity of variables limit inferences that can be drawn from what experiments can be carried
out.
There is the Processing within the Brain of the neural signals from the stimulation within the ear.
The nerves cells adjacent to both the inner and outer hair cells connect to the same region of the brain
(within the cochlear nucleus of the brainstem) but to different functional areas within this region.
These two areas are connected through two different branching networks of connections to both
auditory and to a broad spectrum of non-auditory areas of the brain. The consequences of these
processes are not transitory: for example, research by Akira Ishii et al. has shown when fatigued
volunteers were exposed to the sound of a metronome for 30 minutes while continuing to perform a
fatiguing task on day 1, that on day 2 the metronome sound on its own induced symptoms of fatigue.
The current state of the art tools available to science to explore the brain enable 3-dimensional
imaging of the active areas of the brain in controlled circumstances by detecting the electrical and
magnetic effects of brain activity. While the technical ingenuity of the design of these tools is
impressive, they are quite limited. For example, using these tools would not enable a direct causal
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link to be established between the inputs to (“1”, “+” “1”,”=”) and output from (“2”) a basic
electronic calculator.
There is the Perception of Noise. Having been processed and interlinked through a hierarchy of
functional levels within the brain, integrated information received from multiple stimuli is combined
in the generation of perception. One particular singular aspect of perception is loudness. The
International Organization for Standardization (ISO) develop and publish International Standards,
including the standard “ISO 226:2003: Acoustics - Normal equal-loudness-level contours.” that forms
the basis of the dB(A) measure of loudness. On their web-site they state:
“This International Standard specifies combinations of sound pressure levels and frequencies of
pure continuous tones which are perceived as equally loud by human listeners. The specifications
are based on the following conditions: the sound field in the absence of the listener consists of a
free progressive plane wave; the source of sound is directly in front of the listener; the sound
signals are pure tones; the sound pressure level is measured at the position where the centre of the
listener's head would be, but in the absence of the listener; listening is binaural; the listeners are
otologically normal persons in the age range from 18 years to 25 years inclusive.
The normal equal-loudness-level contour is the equal-loudness-level contour that represents the
average judgment of otologically normal persons within the age limits from 18 years to 25 years
inclusive
An otologically normal person is a person in a normal state of health who is free from all signs or
symptoms of ear disease and from obstructing wax in the ear canals, and who has no history of
undue exposure to noise, exposure to potentially ototoxic drugs or familial hearing loss.”
The role that ultrasound plays in various mental processes is not well understood, but it is clear that it
is not available to perception and is thus excluded from the dB(A) measure of loudness.
There is the Attention to Noise. Attention selects among the many and various stimuli that are
available to perception. Consciousness and the nature and force of stimuli play roles in directing
attention. Consciousness operates in a range of purposefulness between focussed intent and
dormancy: towards either end of this range, stimuli that are not supportive of the purpose of
consciousness exert greater force on attention. Stimuli present themselves in a range between
pleasing and displeasing: those stimuli towards either end of this range present themselves with
greater force than those towards the centre of the range. Stimuli may force themselves on attention in
conflict with the purpose of consciousness. There are wide ranges of reaction to and ability to cope
with this conflict among the population at large.
Limits of scientific understanding of noise
There is limited scientific understanding of the interface within the ear between the physical
characteristics of noise and the neural system. The adage used until recently “What you can’t hear
can’t affect you.” is now discredited by research demonstrating that sounds that can’t be heard
(perceived) do in fact resonate within the ear and stimulate the nervous system. This change in
understanding must serve as a clear warning to us. Our current understanding of noise “from the ear
in” is limited. In our guidelines we must err on the side of caution.
The scientific understanding of the effects within the neural system is at a primitive stage, particularly
in establishing cause and effect relationships. Evolution does not equip us to receive stimuli that have
no effect. This and the fact that stimulation from ultrasound does not affect perception and as a
consequence does not directly impinge on consciousness leads to the conclusion that is has other
unconscious effects. As of now, the scientific understanding of what these effects are is limited. The
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limitations on our understanding of what these and other effects are must not be taken as evidence that
there are no such effects. We must acknowledge our ignorance of the effects of noise within the
neural system and act accordingly. Again, in our guidelines we must err on the side of caution.
The dB(A) measure of loudness is a well-defined scientifically based measure. However, it has
limitations. It is a measure based on a particular subset of the population. It is based on controlled
circumstances where a singular relationship in space between the participants and the sound source is
fixed. It is based on sounds of a single frequency, one frequency at a time. It is a measure that is
normalised: the actual response of the individual participants is subsumed into an average. It is a
measure of sounds as they are perceived. It is a measure where the attention of the participants is
focussed on the sound that they are listening to.
The measure is thus not representative of the population as a whole: in particular, it is not
representative of children, whose development is susceptible to disturbance by intercipient noise. It
bears little or no relationship to peoples’ experience of noise in general and in particular to their
experience of noise from wind turbines. In its definition it avoids any measure of variation among
individual. It is a measure of perception only: it makes no attempt to measure the effects of sounds
other than on perception and as a consequence gives no measure at all for sounds that are not
perceived. It provides no measure of the effects of noise on attention – the aspect of sound that is of
greatest significance for consciousness and that scientist openly state is little understood.
The dB(A) measure of loudness is one of a family of such measures all of which suffer from a similar
set of limitations. These limitations are one particular reflection of the limitations of current scientific
understanding of noise from the ear in.
The Marshall Day report
The Sustainable Energy Authority of Ireland (SEAI) commissioned Marshall Day to compile a report
to form one of its inputs into the review of the Wind Energy Development Guidelines. The report “Examination of the significance of noise in relation to onshore wind farms” - has as its stated
objective to: “...obtain evidence upon which to evaluate the appropriateness of the Wind Energy
Development Guidelines in relation to noise impacts and if considered necessary suggest changes.”
Given that the commissioned Marshall Day report is a major source of information for the process of
reviewing the Wind Energy Development Guidelines it is appropriate to comment on the report in this
submission.
In section “3.4 Special characteristics”. The report refers to Amplitude modulation which it describes
as “a sound which noticeably fluctuates in loudness over time” and impulsiveness which it describes
as “transient sound having a peak level of short duration, typically less than 100 milliseconds.” The
report states “neither impulsiveness nor amplitude modulation have widely accepted metrics that are
field proven and are shown to correlate with peoples subjective impression of the sound. This, in turn,
prohibits the development of prediction tools and regulations.” While it is not feasible to regulate that
which cannot be measured, it is certainly not acceptable that the guidelines ignore issues that impinge
on the people simply because they cannot be measured. The impracticality of specifying measurable
regulations for these characteristics is a further indication that in the regulations we should err on the
side of caution.
Also in this section, Infrasound is describes as “noise at frequencies below the normal range of human
hearing, i.e. <20 Hz”. In the context of infrasound the report cites a 2010 public statement from the
Australian National Health and Medical Research Council (NHMRC) as follows “There is no
published scientific evidence to positively link wind turbines with direct health impacts”. A public
statement dated July 2010 on the NHMRC web site states “there is currently insufficient published
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scientific evidence to positively link wind turbines with adverse health effects” (emphasis added). A
PDF file of the public statement accessible from the website states “there is no published scientific
evidence to support adverse effects of wind turbines on health”. This latter statement is clearly at
odds with the facts. There are many published scientific reports reporting lower overall quality of
life, physical quality of life, and environmental quality of life of individuals residing in the proximity
of wind farms, such as those reports identified in appendix G of the Marshall Day report:


Item 1. Nissenbaum et al. 2012 “The adverse event reports of sleep disturbance and ill health by
those living close to IWTs are supported.”
Item 6. Hanning, CD.,Evans, A., (2012) British Medical Journal “A large body of evidence now
exists to suggest that wind turbines disturb sleep and impair health at distances and external noise
levels that are permitted in most jurisdictions, including the United Kingdom.”
Finally on the matter of the NHMRC public statement, the evidence in the statement was current in
2009.
As indicated above the effects of noise from the ear in is poorly understood. Because of this and
because the tools currently available to scientists to research these effects are primitive in relation to
the research required there is little direct causal evidence relating noise from wind turbines to the
plentiful of anecdotal evidence of the ill-effects of this noise. As stated by Hanning, CD., and Evans,
A., (2012) in the British Medical Journal contribution referenced above “experts contend that the
quantity, consistency, and ubiquity of the complaints constitute epidemiological evidence of a strong
link between wind turbine noise, ill health, and disruption of sleep.” The absence of direct causal
evidence in the Marshall Day report must be understood in the context of the limitations of the
scientific understanding and of the abundance of the anecdotal evidence and must not be read as “no
evidence”.
The report makes no reference to attention to noise.
Experience of noise
The variation in the effects of what people hear is illustrated by comparison of the effects of hearing
the noise of wind turbines at even low dB(A) levels with the effects of listening to music at the same
level. Many people have experienced the “flight or fight” adrenaline rush associated with a noise that
goes bump in the night. What we hear has a great variety of effects on our moods, emotions, focus,
sense of well-being and many other physiological, psychological and behavioural effects. For many
people, the noise from wind turbines can have considerable negative effects in these areas.
In the quiet of the night, to a student with intent focussed on the complexity of a concept of study or
to any individual trying to sleep, the effect of the sound of a dripping tap at a level of loudness just
above the hearing threshold can range from irritating to infuriating. It is within the control of a
household to fix a dripping tap. It is not within their control to quieten a wind turbine that elicits
similar effects: this lack of control can exasperate residents to the point of distress. The seeming life
sentence to residents of one or more wind turbines in their locality can exacerbate persistently over
many years these negative effects.
For individuals whose attention is particularly sensitive to noise such as individuals suffering from
any of the autistic spectrum disorders, and to the families of these individuals, the absence of any
reference to attention to noise in the considerations for the planning guidelines is unacceptable. We
judge democracies by how well they treat their minorities. Ignoring this minority is reprehensible.
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Guidelines
The power rating of wind turbines has been growing in recent years and looks set to continue
growing. The spectrum of noise generated shows a downward shift in frequencies with increased
turbine power: lower frequency noise travels further. On larger turbines the blade tips travel further
and faster resulting in greater wear and accretion on the blades which in turn results in the increase in
noise with turbine age occurring more rapidly. Newer larger turbines are, by definition, not tried and
tested in real life situations: there may be other as yet unknown effects of larger turbines. The
guidelines should reflect this possibility and err on the side of caution.
We Irish are now establishing Wind Energy Development Guidelines for ourselves. Due to the limits
of the scientific understanding of the effects of noise on people, the mistaken assumptions made
because of this in the past, the difficulties in measuring physical characteristics of noise, and the lack
of field experience of newer larger turbines, when drawing up our guidelines we should err on the side
of caution.
Ireland is among the best positioned countries in the world to harness wind energy. There are wind
farm locations in the country sufficient to at least meet our renewable energy needs that are
sufficiently removed from noise sensitive properties to eliminate the possibility of ill-effects of wind
turbines on the residents closest to the wind farms. The guidelines should acknowledge this fact,
should not limit themselves to best international practice and should represent an appropriate Irish
solution to an Irish problem.
The residences of many households have not been constructed with attenuation of turbine noise in
mind. Many people desiring a healthy personal environment leave windows open day and night for
ventilation purposes. Many people consider their garden to be their “room outside”. Many parents
urge their children to ”go out and play”. Where noise is concerned the distinction between indoor and
outdoor living is somewhat artificial, particularly for rural residents, the group most likely to be
affected by wind turbine noise. An outdoor noise limit of 30 dB(A) attributable to one or more wind
turbines, suggested as being appropriate for indoors in the draft guidelines, should be applied in order
to restrict noise from wind turbines at noise sensitive properties.
Measurements of wind turbine noise at a noise sensitive property requires specialist skills, expensive
equipment and a significant commitment of time. These are not available to most residents.
Engagement with planning enforcement agencies requires a significant commitment of time and
confident communication skills. These are not available to many residents. The commitment,
resources and motivation of planning enforcement agencies across the country is variable. A simple,
easily understood and effective planning regulation is the setback distance. The setback distance
should be such that in all but exceptional circumstances the outdoor noise limit at noise sensitive
properties will not be exceeded.
In general, the noise from a wind turbine at a particular distance from the turbine increases with both
turbine height and turbine rated power. While currently the typical number of blades on a turbine is 3
it is desirable to have additional blades as they harness additional energy: it is probable that
technological advances will enable attachment of additional blades and additional blades will result in
noisier turbines as well as higher flicker rates.
As a consequence of these considerations the setback distance should be a function of both height and
rated power of turbines. I have neither the tools nor the skills to determine the parameters of this
function but it should be a simple function, such as 2 meters for every 1 meter in turbine height plus 4
meters for every 10 kilowatts of turbine rated power, but with a minimum setback distance of 800
meters.
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Concluding comments
I make this submission holding the conviction that humanity must stop treating the atmosphere as a
dump for its unwanted gasses, greenhouse gasses in particular, and as an advocate of renewable
energy particularly here in Ireland which, as mentioned above, is among the best positioned countries
in the world to harness wind energy.
Submitted by
Tim Stuart
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