Impact of turbine noise on health and well-being

10.0 Concluding Remarks

In Europe (WHO, 2009) noise is a recognised environmental pollutant that degrades sleep, quality of life and general function. Utility-scale wind energy generation, involving the saturation of an optimum number of wind turbines in a fixed area, is not without health impact. However, the management of these impacts have been hindered by a systemic failure in the prediction of noise levels and sound characteristics emanating from wind turbine installations. I am not implying that these shortcomings are exercises of deceit by members of the acoustics discipline, but rather there is substantive international evidence showing that these errors are due to a lack of adequate methodology. Deceit has, arguably, been nurtured by the lack of acknowledgment regarding the limitation of current methods. Mr Rick James will describe these limitations in the statement that he presents to this hearing.

10.2 New Zealand has a poor record when it comes to the responsible positioning of wind turbine installations. Many of the turbine installations erected in the Manawatu region were initially welcomed by residents who supported renewable energy. However, this initial enthusiasm was based upon reassurances from the developers that turbine noise would not intrude into homes. The resulting lack of concordance between the predicted impacts of the noise and the actual impacts of the noise has lead to a rise in resistance to wind turbine installations in the Manawatu region. A similar situation occurred at Makara, although in this instance the turbines were not initially welcomed by the bulk of the community. Further evidence comes from a recent compliance report (Lloyd, 2010) undertaken on the Te Rere Hau wind turbine installation that indicates that the complaints made by nearby residents regarding noise exposure are justified on the basis of recent noise level readings. Note that these readings are discordant with those originally predicted and do not comply with the original resource consent conditions.

10.3 I further suggest that it is a mistake to judge potential health effects on noise level alone. Given that noise level explains between 15 - 20 percent of the variation in the annoyance response across individuals, I would recommend that noise level be given a 15 - 20% weighting in the decision as to whether the turbines should go ahead or not. Instead most weight should be placed on the potential amenity threats and the impact of vulnerable groups in the valley, including the elderly and children, and noise sensitive individuals. Because of the discrepancies between predicted and actual noise levels it would be prudent to rely on evidence coming from real people at established wind turbine installations (e.g., Te Rere Hau, Makara, Tararua) than disputed mathematical models.

10.4 Chronic (i.e., long term) exposure to unwanted sound can compromise health, and these adverse reactions to noise do not easily disappear with repeated exposures. It is proposed that adverse reactions to noise can reduce over time, a process known as habituation, which can be a physiological or behavioural. The WHO (1999) asserts that a habituation to noise is a highly individual matter. Noise sensitive individuals or individuals with certain types of mental illnesses are less likely to habituate to noise than noise resistant individuals. This lack of habituation is expected given the evolutionary significant roles undertaken by the auditory system, and as such we would predict, and indeed find, differences across individuals.

10.5 There are numerous reasons why wind turbine developers should be discouraged from placing turbines in the green belt areas around cities. The decision from this hearing is crucial in as much as it will determine the boundaries for turbine placement. Supporting the proposal will expose a good number of other lifestyle/semi-rural communities to the threat of turbines, while opposing the proposal will signal that developers need to explore less populated areas outside of the greenbelts. From the original consent hearing held in 2008 I understand that New Zealand is not lacking in wind resources and it there is vast opportunity to develop more isolated areas.

10.6 Ruling against the Mill Creek proposal will financially disadvantage a minority of the community. Supporting the Mill Creek proposal will compromise the well-being of a great many more residents. In addition, those who elicit strong emotional reactions to the loss of amenity that will accompany the turbines will also likely exhibit high annoyance responses to the turbine noise that will encroach the Ohariu Valley soundscape. Furthermore, those individuals who are highly noise sensitive will likewise suffer from the turbine noise.

10.7 It is possible that psychological therapies such as Cognitive Behavioural Therapy (CBT) could be used to reprogramme the thought processes of those experiencing annoyance through the amenity route, though such a solution may be seen as morally reprehensible by some. For the individuals with noise sensitivity CBT would not be effective as this is a trait rather than a state condition. For both these groups I would advise leaving the Ohariu Valley if the turbines are constructed as habituation is unlikely and sleep deprivation and/or stress-related disease is likely and, from the onset, quality of life will decrease.

10.8 It is not clear to me that Meridian has undertaken sufficient duty of care in assessing the health impacts of turbines in the Ohariu Valley. For example, to the best of my knowledge they have not assessed prevalence of vulnerable groups (elderly, children) or traits (noise sensitivity) or considered factors that predict amenity values (e.g., length of residence). Nor have they reasonably dealt with the experiences of residents in the adjacent Makara Valley. There is a sense that they have attempted to suppress meaningful debate in the direct links between noise and health and instead present arguments based on fears of technology. While I have some sympathy for this argument in certain contexts (e.g., the placement of cell phone towers) the approach is not relevant to the current context.

10.9 Based on these observations (i.e., 10.8), based on data I have collected and analysed, and based on the current state of knowledge linking noise to impaired health in vulnerable persons, I opine that consent should not be granted for the proposed turbines in the Ohariu Valley.

Daniel Shepherd holds a PhD in psychoacoustics, a Masters of Science degree in psychology, a Bachelor of Science degree in psychology and biology. His PhD dissertation was a study on the abilities of human observers to discriminate between low level sounds. Currently he is a Senior lecturer at the Auckland University of Technology in New Zealand, lecturing in the areas of psychological assessment, biopsychology, and statistical analyses at both the undergraduate and postgraduate levels. He has published papers on the psychophysical measurement of human hearing abilities and has presented at numerous international conferences on the topic.