Wind and Property
Wind turbines negatively affect the value of property by varying amounts depending on the proximity of the individual house to the wind farm. Five different studies concur that this drop is between 11% and 40% for homes located within 2 km of a wind farm.
A 2007 report on the impact of wind farms on house prices in the UK (Sims. 2007), authored by Dr Sally Sims and Peter Dent of Oxford Brookes University and funded by the Royal Institute of Chartered Surveyors (RICS) Education Trust, found that terraced houses within 1.6 km of a wind farm dropped by 54%, with semi-detached houses dropping by 35%.
Michael McCann (2013) concurred with this finding. His study for a wind farm in Tipton County in Indiana included a literature review of 11 previous US studies. He concluded that properties within 2 kilometres of a wind farm experienced a drop of between 25% and 40%.
The Lawrence Berkeley National Library (LBNL) published a report in 2013, funded by the US Department of Energy, which claimed that the property-value effect of wind farms was likely to be small on average if it is present at all. Their report was extensive and examined over 50,000 home sales in proximity to 67 different wind facilities. However, only 2.3 % of the homes were within 1.6km of a wind farm with many up to 16 km away. The report’s own data found that homes located within one mile of the turbines decreased in value by 28 percent compared to homes located within 3 to 10 miles from the turbines. McCann explained that that many industry supported reports tended to play down the impact by “Pooling data from multiple diverse locations… which tends to set wide parameters that conceal actual impacts”. We have seen this misleading practice in Ireland also, where wind developers use entire counties as a basis for comparing property.
Perhaps the most comprehensive and independent study to date is that of the London School of Economics (LSE) (2013). This report, which will be launched in Spring 2014 and includes over a million property transactions, has found that larger wind farms of 20 or more turbines reduce property values by up to 12% within 2 km and by 3% at an 8 to 14 km distance. They also concluded that the amount required to compensate householders for their loss of visual amenity would be £12 million approx. for a typical 11 turbine wind farm based on the average number of households with turbines currently visible within 4 km. Importantly from an Irish perspective where many large wind farms are planned, they say; “The corresponding value for large wind farms will be much higher than this as their impact is larger and spreads out over much greater distances”. An important limitation of this study is that the average turbine in their extensive sample area was 90 metres high to tip. In Ireland, almost all planned turbines range from 130 meters to 185 meters.
Sims. 2007. Oxford Brooks University. What is the impact of wind farms on house prices? View.
McCann. 2013. Property value Impact and Zoning Compliance Evaluation. View.
Lawrence Berkeley National Library. 2013. View.
LSE. 2013. Gone with the wind: Valuing the local impacts of wind turbines through house prices. View.
Royal Institute of Chartered Surveyors 2013. View.
Davis. 2008. Lincolnshire valuation tribunal 2525475645/032C. View
Wind Turbine Noise
Uninterrupted sleep is known to be a prerequisite for good physiological and mental functioning of healthy persons (Hobson, 1989). A large body of evidence now exists to suggest that wind turbines disturb sleep at distances and external noise levels that are permitted in most jurisdictions (Evans & Hanning. 2012. BMJ).
World Health Organisation (WHO)
For continuous noise, to avoid sleep disturbance, WHO recommends an indoor limit of 30 dB (A), but also notes that, if the noise includes a large proportion of low frequency noise, “a still lower guideline value is recommended because low frequency noise ….. can disturb rest and sleep even at low sound pressure levels” (WHO, 1999).
Low Frequency Noise
The noise generated by wind turbines has a large low frequency component. Low frequency noise travels further than higher frequency noise (Moller & Peterson, 2010) and is more annoying than higher frequency noise. (Leventhall, 2004; Van den Berg et al, 2008). Current noise measurement techniques tend to obscure the contribution of impulsive low frequency noise (Curran Associates, 2011).
Sleep Disturbance Studies
Studies have found that residents living within 1.4km of industrial wind turbines, or where the outdoor turbine noise exceeds 35 dB LAeq, suffer from disturbed sleep (Peterson et al, 2004; Nissanbaum, Armani & Hanning, 2011; Van den Berg, 2004).
Impulsive, Relentless Noise
Large, industrial wind turbines, by their nature, are designed to operate even when wind speeds at ground level are low. In a stable atmosphere, which often exists at night, the difference in wind speed between top and bottom of the rotor is much higher than at other times. This changes the swishes to “clapping, beating or thumping” and can be heard clearly at distances at least up to 1km (Van den Berg, 2004).
Danish Statutory Order
In a study conducted by H Moller and CS Pedersen, it was found that the Danish outdoor limit of 44 dB(A) would result in the low frequency noise exceeding 20 dB(A) in many living rooms of neighbouring residences. Problems are much reduced with an outdoor limit of 35 dB (A) (Moller & Peterson, 2010). As a result, a Danish Statutory Order was enacted in January 2012, and the Danish indoor limit for low frequency noise inside dwellings is now a maximum of 20 dB (A) (Danish Environmental Protection Agency, 2012).
Irish Wind Turbine Noise Guidelines
The current outside night noise guideline in Ireland is 43dB (A) (D.O.E. 2006). It is proposed to reduce this to 40dB (A), resulting in an indoor noise level of 30dB (A) (D.O.E. 2014). An indoor noise level of 30 dB (A) will not protect sleep where there is a large low frequency element, and is in contravention of the WHO guidelines on Community Noise, 1999
J Hobson.1989. Sleep Scientific American Library. View
C Hanning: Wind turbine noise. BMJ 2012; 344:e1527. View
World Health Organisation. 1999. Guidelines on Community Noise. View
H Moller and CS Pederson.2010.Low Frequency noise from large wind turbines. View
Leventhall HG.2004.Low frequency noise and annoyance. Noise Health. View
Van den Berg G, Pedersen E, Bouma J, Bakker R.2008. Project WINDARMperception. Visual and acoustic impact of wind turbine farms on residents. View
Bray W, James R.Proceedings of Noise-Con 2011, Portland, Oregon, 25-27 July 2011. Curran Associates 2011. Dynamic measurements of wind turbine acoustic signals, employing sound quality engineering methods considering the time and frequency sensitivities of human perception. View
Pederson E, Pederson Waye K.2004.Perception and annoyance due to wind turbine noise – a close response relationship. View
Nissanbaum M. Aramini J, Hanning C.2011.Adverse health effects of industrial wind turbines: a preliminary report.
GP Van den Berg.2004. “Do wind turbines produce significant low frequency sound levels?”11th Int. Meeting on Low Frequency Noise Vib. It’s Control, Maastricht. The Netherlands. View
Danish Environmental Protection Agency, 2012 Statutory Order on Noise from Wind Turbines. View
Department of the Environment, 2006 Wind Energy Planning Guidelines. View
Department of the Environment, 2014 Draft Wind Energy Planning Guidelines. View
Wind Turbines, like other tall structures, can cast long shadows when the sun is low in the sky. The effect known as ‘shadow flicker’ occurs when the rotating blade blocks the sun and causes the shadow to flick on and off. These shadows can stretch for long distances depending on turbine height and orientation of the sun.
To view shadow flicker: View Youtube Video
- the sun is shining and is at a low angle (after dawn and before sunset); and
- the turbine is directly between the sun and the affected property; and
- there is enough wind energy to ensure that the turbine blades are moving.
In the northern hemisphere people located East-NE or West-NW from the turbine will be adversely affected by shadow flicker. (Verkuijlen E, 1984)
Rotating blades interrupt the sunlight producing unavoidable flicker bright enough to pass through closed eyelids, and moving shadows cast by the blades on windows can affect illumination inside buildings.
It is acknowledged that “…shadow flicker can be an issue both indoors and outdoors when the sun is low in the sky. Therefore, shadow flicker may be an issue in locations other than the home.” (Minnesota Department of Health (MDH) 2009). Shadow flicker modelling must consider human exposure to shadow flicker outside a building.
Under the current Irish Wind Energy Planning Guidelines (2006) it is “recommended that shadow flicker at neighbouring offices and dwellings within 500m should not exceed 30 hours per year or 30 minutes per day”. The guidelines allow up to 30 hours of shadow flicker per year per dwelling.
In England the recommended shadow flicker setbacks for current wind turbine designs are 10 rotational diameters which would typically translate to approximately 1000m. Shadow flicker can be mitigated by siting wind turbines at sufficient distance from residences likely to be affected. Flicker effects have been proven to occur only within ten rotor diameters of a turbine. Therefore if the turbine has 80m diameter blades, the potential shadow flicker effect could be felt up to 800m from a turbine.
In terms of the health impact, there are particular concerns about people who have epilepsy as flashing lights are known to trigger certain types of photosensitive epileptic seizure (which is why television announcements give warnings about flash photography).
Such photosensitive epilepsy (PSE) occurs in one in 4,000 of the population. It is likely that the frequency of flicker produced by wind turbines is usually lower than the 2.5 – 3 hertz that is a risk factor for epilepsy trigger. However, the combination of flicker from several turbines “can have a higher frequency than from a single turbine.” (Harding, Harding & Wilkins)
Two examples of seizures induced by wind turbines on small wind turbine farms in the UK were reported to the authorities in 2007. Anecdotal evidence would also suggest that shadow flicker causes stress and annoyance. Mr. Philip Hickey of Ballindaggin, Co. Wexford whose house is 370m away from a 120m turbine said the house was hit by shadow flicker due to the low winter sun from October to February. “The flicker would make you feel sick. It is like strobe lighting going through the property” he said. (Independent.ie 2014)
Verkuijlen E, Westra CA. (1984) Shadow hindrance by wind turbines. Proceedings of the European Wind Energy Conference. October 1984, Hamburg, Germany. View
Minnesota. Department of Health (MDH). 2009. Public Health Impacts of Wind Turbines View
Harding, Harding & Wilkins. 2008. Wind turbines, flicker, and photosensitive epilepsy: Characterizing the flashing that may precipitate seizures and optimizing guidelines to prevent them. View
Institute Aston University, Birmingham, United Kingdom; and Department of Psychology, University of Essex, Colchester, United Kingdom.
Independent.ie – Irish Independent 25/02/14 Why Wind Farms Have Power to Divide Country. View
Autism and Wind Turbines
Autism is a neuro-developmental disorder that affects the development of the brain in the area of social interaction. It has been well documented that individuals on the Autistic Spectrum experience a degree of sensory impairment which renders them extremely sensitive to specific sounds, light and reflection and in many cases touch. To this end, it is reasonable to assume that individuals on the Autistic Spectrum will be even more susceptible to infrasound, mechanical noise and shadow flicker from wind turbines than the general population
In fact, in the UK, Planning Inspectors and Planning Authorities have been sufficiently convinced of the effects of infrasound on those with Autistic Spectrum Disorders that they have refused planning permission for several wind energy facilities on the grounds that there were individuals living nearby with the condition. For example, a wind energy facility planned for North Lincolnshire was rejected in 2010 because of the serious effect it would have on twin autistic boys living nearby. A report from a Clinical Psychologist in this case pointed out the “extreme distress” that turbines could cause to people with autism. In this particular case, the twin boys had a fixation with spinning objects and the report asserted that “the time they spend engaged in spinning and observing objects had to be limited in order to allow them to engage in other more meaningful activities.” In another case in Aberdeenshire, Scotland in 2011, the parents of a severely autistic boy forced a wind energy company to backtrack on plans to site wind turbines near their home on the basis of evidence from Consultant Clinical Psychologist Dr. Susan Stebbings. Closer to home, Dan Danaher reported in the Clare Champion newspaper on the 26th Jan 2012 how a Co. Clare mother claimed that her life “had been turned upside down” following the erection of a 19.6m agricultural turbine in a neighbouring property.
The turbines planned for Ireland are 185m high, almost ten times the height of the 19.6 m high turbine in Co. Clare.
Cristina Becchio, Morena Mori, Umberto Castiello (2010) Perception of shadows in children with ASD. View
Catherine Purple Cherry & Lauren Underwood. The ideal home for the Autistic child. Autism Science Digest; The Journal of Autismone, Issue 03. View
Flavia Cortesi et al (2010). Sleep in children with Autistic Spectrum Disorders, Sleep Medicine 11 (2010) 659-664. View
Stansfeld & Matheson (2003) Health Impact Assessment Ch 7. B.A.C. View
Lillian N Steigler & Rebecca Davis (2010) Understanding Sound Sensitivity in Individuals with Autistic Spectrum Disorders, Online First. View
BBC website 27 April 2010. View
The Press and Journal, David Mc Kay 23 April 2011. View
The future of Irish tourism is inextricably linked to the quality of the environment. Our scenic landscapes, coastline, rivers and lakes, and cultural heritage are the bedrock upon which Irish tourism has been built. The economic viability and competitiveness of the Irish tourist industry can only be sustained if the quality of these resources is maintained. Now, more than ever, Ireland’s tourism industry relies on strong and appropriate environmental policies.
A Failte Ireland Draft Report as published by RTE on the 12th September 2013 found that 24% of tourists said wind farms would negatively impact on any future plan they had to holiday in Ireland. The unpublished study also shows that tourists would prefer to see turbines built on bog land or near urban areas rather than along the Irish coast or near good quality farmland. Fáilte Ireland will use this research to decide what planning applications for wind turbines it may or may not object to on the grounds of whether they are perceived to pose a risk to Ireland’s tourism industry.
To put these figures in context, 24% of a €5.5 billion industry annually, is a €1.3 billion potential tourist revenue loss. Furthermore, Ireland’s tourism employs ca. 185,000 people. To extrapolate the potential effect, twenty four per cent of 185,000 is a potential job loss of 44,400 jobs.
The potential loss of 44,000 indigenous jobs should be analysed against the Irish Wind Energy Association (IWEA) internal survey which suggests that there are 3,400 people in full time employment in the wind energy sector (this figure should itself, of course, be tested by reference to actual PAYE PRSI employment data), when the sector has “just over 2,000 megawatts of renewable generation connected to the power system in Ireland”.
The Failte Ireland survey was carried out in 2012 when there were less wind turbines on the Irish landscape. However and importantly, no consultation was carried out on the massive industrial scale, density, locations and height of the proposed wind turbine projects. Tourists surveyed would not have appreciated for example that one developer (Mainstream) has since published that it intends building “5,000 MW mainly in the Midlands”, Element Power has published that they intend building a further “3,000 MW”, and each of the three Semi-State owned companies Bord Na Mona, Coillte and ESB Wind Energy also have plans.
Worryingly, the two most important areas; “the Irish coast or near good quality farmland” are where private developers have been targeting.
Furthermore, in 2012 the scale of the €3.2 billion Eirgrid
Pylon project was not consulted upon, which is the infrastructural arm to the massive wind energy plan.
Therefore if the full scale of the proposals were identified to tourists, the 24% figure could in fact be significantly higher.
RTE News. View
DCENR.2013.Wind energy project may only proceed in compliance with a national policy. View.
Wind Turbine Heights
There are plans to build approximately 3000 to 4000 wind turbines of up to 185m throughout the island of Ireland. If these plans go ahead, these turbines will be by far the largest turbines in Ireland and indeed Europe. To put it in context, these turbines will be more than 1.5 times the height of the Millenium Spire in Dublin which stands at 120m. The tallest turbines in Europe are in the Stegelitz Project in Saxony Anhalt in Germany where there are 16 turbines with a tip height of 180m.
The tallest turbines that currently exist in Ireland are at Mount Lucas, Co. Offaly where there are 28 turbines of 150m in height currently being constructed. Such a proliferation of between 3000 to 4000 of this scale in one region would have an enormous negative impact on visual amenity should these developments go ahead. Wind turbines are known to pose various risks regardless of size. It can be shown that some of these risks increase with the height of the turbines. Some of these risks are as follows;
Large wind turbines generate infrasound. Infrasound, sometimes referred to as low-frequency sound, is sound that is lower in frequency than 20 Hz (Hertz) or cycles per second, the “normal” limit of human hearing. The ear is the primary organ for sensing infrasound, but at higher intensities it is possible to feel infrasound vibrations in various parts of the body. Infrasound is associated with sleep disturbance (Persson Waye, 2004; Nissenbaum, Armani & Hanning, 2012). Sleep disturbance has adverse effects on health such as obesity, heart disease, mood disorders and other issues (Harvard Medical School). It has been found that the relative amount of emitted low-frequency noise is higher for large turbines(Moller & Pederson, 2010). It follows from this that the health risks associated with low-frequency noise would also increase as the size of the turbines increase.
Birds can collide with any large structure. One study has found that for all onshore turbines in the US, annual model-predicted mortality increased nearly ten-fold across the hub heights in the data set(Loss, Will & Marra, 2013) This translated into an average of 6.2 bird deaths per turbine per year for the highest turbines. Hub heights in the study were 36-80m. The hub height for a 185m turbine is in the region of 120m, 50% higher than the highest in the study. It therefore follows that turbines of 185m would give rise to even greater mortalities. There are many variables is assessing collision risk (species, flight path etc) but the principle remains that higher turbines give rise to a greater risk of collision and mortality.
Wind turbines can accumulate ice under certain atmospheric conditions such as ambient temperatures near freezing combined with high relative humidity(Wahl & Giguere, 2006).
In addition, rotating turbine blades can propel ice fragments up to several hundred meters from the turbines if conditions are right(Wahl & Giguere, 2006). It follows that increased turbine height would increase the risk of ice accumulating in the first place, and the larger rotor blade sizes of these turbines would increase the potential throw area of the ice fragments.
The above risks increase as turbine height increases. These risks must surely be amplified further when there is a large concentration of turbines in the one region.
- Effects of Low Frequency Noise on Sleep. K Persson Waye. View
- Effects of industrial wind turbine noise on sleep and health Michael Nissenbaum, Jeffery Aramini & Christopher Hanning. Noise & Health. 2012. View
- Sleep and Disease Risk. Division of Sleep Medicine at Harvard Medical School. View
- Low-frequency Noise from Large Wind Turbines. H Moller and CS Pedersen, 2010. View
- Estimates of Bird Collision Mortality at Wind Facilities in the Contiguous United States. Loss, Will, Marra 2013. View
- Ice Shedding and Ice Throw – Risk and Mitigation. Wahl, Giguere, GE Energy 2006. View.
Heights of Turbines & Pylons Illustrated