Wind Turbines – The Issues, the Hype, the Truth, and Unresolved Questions
A Closer Look at Public Safety, Health Effects (from noise), Electrical System Security, and Sustainability
Wind turbines seem to be the “poster child” for the “green” movement. The hype about wind turbines from their advocates would lead the public to believe that wind turbines are free from adverse impacts and only self-serving NIMBY’s who fear any development oppose them. This list looks at the issues, the hype heard, the truth as supported by evidence, and significant unresolved questions.
|The Issue||The Hype||The Truth as Supported by Evidence||Unresolved Questions|
|Public Perception||We hear Canadians, and enlightened people worldwide, love wind turbines because they are “green”, and the only opponents are those afraid of change, unwilling to address environmental issues or who are biased supporters of some other generating technology.||After studying the issues carefully, one finds that there are real questions that need to be addressed. People trying to bring the truth to the table are environmentally aware, well informed, and want to present an approach to environmental issues that considers all the issues independent of any ideology.||As the public becomes educated about the issues, risks, and concerns of large industrial wind turbines, how will perception change? Will the installation of large wind turbines without consideration of the issues result in long lasting adverse effects that could have been addressed?|
|Impact on the cost of power||
We hear the wind is free, and limitless. Even better, we hear installing wind turbines will not cost the power customer anything as financiers with a social conscience are willing to install the turbines at their cost and risk. What could be better?
We hear that 1 MW of wind turbine capability will supply the power needs of 350 Ontario homes.
We hear that Ontario has the ideal situation, as “the wind is always blowing somewhere” and hydraulic generation can replace wind on windless days, saving water “in the bank” above hydro generators on windy days.
The wind passing wind turbines that can generate electricity is controlled by well understood atmospheric conditions. Experience shows that on a time based average, wind turbine output rises overnight, and falls in the morning. This does not match the electrical demands posed by society.
Looking at the 100 days from June 1 to Sept 8, in 2006 and again in 2007, on over half of the days each 1 MW of wind turbines was not able to supply the electrical needs of 350 homes, but only the needs of zero to 25 homes. Over the period from May 2006 to June 2008, there were at least 173 periods of at least 10 hours in duration, up to 125 hours (over 5 days) when 1 MW of wind turbines were able to supply no more than 0 to 25 homes. These gaps in wind turbine output occurred during hot summer days, cold winter days, and stormy spring or fall days. When we most need the power, experience shows it may not be available from wind.
Wind turbines contribute energy, but cannot be counted on to add to Ontario’s system peak capacity, as we cannot be assured there will be wind! We cannot expect existing stations to replace wind at peak, as Ontario runs all available generators on peak.
Developers that install wind turbines will profit very nicely from their investment. The cost of the turbines can be written off against cash flow from other operations, reducing taxes. Long-term guarantees ensure energy produced will be bought at a premium price, whether at a high or low power demand time. The consumer will pay dearly to repay those investments.
Who benefits most from the installation of wind turbines? Consumers or the developers?
Should we pay a premium price for a generating source that is not available when most needed?
An electrical utility must have backup generation equal to the wind turbine maximum output connected and idling at low load (and low efficiency) – ready to load at all times wind generators are on line, as they can (and experience shows do) vary from low load to full load, and back to low load over short time periods. Should we cost this additional required generation with the cost for the wind generation?
|Public Health and Safety||Hype says that no member of the public has ever been hurt by a wind turbine. The example of the demonstration turbine at the CNE in Toronto is used to assure us that they must be safe, as it has never had an accident.||
While the CNE wind turbine has not failed catastrophically, you cannot get a true measure of safety by examining one turbine for a few years.
In 2004, a handbook for the risk assessment of wind turbines was prepared by the Netherlands Agency for Energy and the Environment. The handbook analyzed over 43,000 turbine years of experience in Denmark, Germany and the Netherlands typical of, although some were smaller than the turbines being installed in Ontario. They found 62 severe incidents and accidents relevant for the safety of those nearby had occurred.
The handbook calculated the frequency of occurrence of actual accidents to show that loss of a full turbine blade, a tower collapse, or the collapse of the turbine from the top of the tower can be expected every 775-turbine years. A group of 100 turbines can expect an accident every 8 years.
The largest contributing factor in the Dutch study was the loss of a turbine blade, with a calculated recommended frequency of 8.4 x 10-4 per year. Actual blade failures in Ontario of large industrial turbines that have resulted in parts of blades disengaging from the tower and landing on the ground is about 4 times higher than the blade failure frequency found in the Dutch study. This may be due to the fact that Ontario turbines are taller, with longer blades (thus more impacted by stresses across the blades from wind shear – per US DoE NREL) and operating in a more severe climate than those in the European study. It also neglects an additional blade failure in Ontario that occurred on a smaller private turbine in which the blade traveled 100 metres.
If 43,000 turbine years of European operation resulted in 62 severe incidents and accidents relevant to safety, when Ontario has 3000 turbines (for the 5000 MW of wind generation proposed by the OPA), if we apply the actual failure rated from the Dutch study, are we content that each year we should expect 4 severe incidents and accidents that may hurt people if setbacks are inadequate?
Does the fact that actual Ontario experience (to July 2008) shows a blade failure rate 4 times higher than the Dutch failure rate not suggest that Ontario failure rates will be even higher?
Should the public be protected by setbacks from accidents such as loss of a 41-metre turbine blade weighing over 10 tons that can travel 250 metres?
Should the public be consoled by apparent safety of a single turbine when proposals will see thousands of turbines installed?
If we do not set adequate setbacks, do we accept the probability that the risk assessment shows that people will be hurt?
Do we accept the injustice to place members of the public whose established homes or travel pathways place them near where wind turbines are installed will be at a level of risk for death or injury well above the risk we accept for members of the public?
|Setbacks of wind turbines for public safety.||
The Canadian Wind Energy Association (CANWEA) website includes a proposed official plan for municipalities that would allow construction of wind turbines within the rotor radius plus 10 metres (e.g. about 50 metres) from property lines, from non dwelling buildings, or from road right of ways. They propose that wind turbines can be located within 200 metres of residences. The hype would seem that the industry feels wind turbines are very safe!
Proponents have said falling bits from wind turbines are like branches falling from trees, implying they are like naturally occurring common incidents.
The Netherlands risk assessment of wind turbines from actual accidents shows that at a 50-metre setback from wind turbines, the individual risk of death is 0.00001 per year – this is 10 times higher than the risk accepted in Ontario for other generating stations or in the Netherlands for wind turbines.
If this risk was applied to all persons in Ontario, we could expect to have 120 deaths due to wind turbines in a year. That risk would be unacceptable to the population.
To bring risk from wind turbines into an acceptable range (e.g. meeting the Netherlands standard) requires a setback of at least 1.5 times the total height of a turbine tower and the blade diameter (or 2 x height + radius).
A simple calculation shows that a 4 kg piece of ice (as documented falling from turbines in Ontario) falling 100 metres hits the ground with the same energy as a concrete bock dropped from a six-storey window.
Standards must be based on tower height and blade length, as turbines are getting bigger and simple distance limitations do not address them.
Why should society impose an additional risk of injury or death upon anyone from a neighbour’s wind turbine – a risk higher than is acceptable in Europe, and higher than the risk from other generating systems? Is accepting a higher risk for individuals “across the fence” from wind turbines justified?
Why place risks above those considered acceptable to everyone on some when it is easy to bring risks to acceptable levels by increasing setbacks?
Why is it a “right” for a farmer with acreages too small to allow adequate setbacks to have tall wind turbines? Have neighbours no rights to personal safety? Should turbine heights not be restricted to that which can be safely sited on the property?
Why do we not restrict wind turbines to areas where the leaseholder accepts the restriction on activity within the lease area? Does not the Ontario PPS demand that developments be separated from other uses?
|Noise impact of wind turbines||
The popular belief is that people who complain about wind turbine noise do so only as an excuse for their dislike of the technology. Noise concerns are dismissed as the excuse of the NIMBY set.
A CANWEA brochure states
“In fact, turbines are so quiet that it’s possible to carry on a normal conversation at the base. At 300 meters from the base, the sound they make has been electronically measured and compared to a whispering voice.” … “much of the sound from the blades is masked by the sound of the wind itself and of the accompanying sound of rustling leaves in nearby trees and shrubs.”
The Ontario Power Authority web site states “Manufacturers of modern wind turbines have also reduced noise levels to that of a quiet whisper.”
The Ontario Ministry of Energy web site states, “Ambient noise from passing cars or rustling leaves is often greater than the sound of a wind turbine.”
Ontario Ministry of the Environment noise standards for wind turbines (prepared in conjunction with CANWEA, the industry advocate group) are not as restrictive as many other countries. For example, the Netherlands, France, Denmark, Germany, and Sweden do not permit as much noise from wind turbines as do the Ontario Standards.
The Ontario MOE permits a wind farm to emit noise above 40 dBA for wind speeds above 6 m/s (21.6 km/h) at a 10 metre reference height. Manufacturers base the turbine sound emissions on a “neutral” atmosphere, as exists during daylight hours, to predict noise from wind turbines at an 80 metre hub height. Experience shows that many people are troubled by wind turbine noise, especially at night. Investigation by Dr. G.P. van den Berg of the University of Groningen in the Netherlands reinforced the atmospheric science fact that the profile of the wind at different elevations changes between night and daytime. After sunset, the atmospheric profile becomes “stable” and there are larger differences between the wind speeds at the ground and at the turbine than in the daytime “unstable” or “neutral” profile. While ground level winds fall at night and background noise falls, the wind speeds at the level of the turbine and the resultant noise increases. Human ears are particularly responsive to sound differences, so the noise from the turbines is perceived as significantly more troublesome at night even if the noise level only increases 4 or 5 dBA.
Work published in the UK (government sponsored) confirmed a hypothesis of Dr. van den Berg, that one of the significant contributors to the annoyance is modulation of the sound from clusters of more than one turbine.
Tracking the situation in Ontario for 100 days in the summer of 2006, on 70 out of those 100 days, the turbine output (as reported by the IESO) increased to the point that it indicated wind speeds were high enough to indicate that “masking” of the noise produced by the wind turbines by ground level winds would be required to meet the Ontario standard. At the same time, the Environment Canada wind speed data recorded for stations near the wind farms showed that ground level winds were below the level that masking could be credited.
To meet the Ontario standard – even on the dBA scale, current 1.65 MW wind turbines need to be about 1500 metres from homes to recognize that at night wind speeds can be high at the turbine while there is no ground speed wind to provide masking – and if allowance is given for gradual increase in noise as blades wear, the distance should be over 1500 metres.
Ontario Standards limit noise in terms of dBA, a scale that attempts to represent the response of our ear to diminish sensitivity at low frequencies. When noise from wind turbines is measured by the dBC scale, it shows a significantly higher reading (typically values measured as 40 to 45 dBA, show values of 55 – 75 dBC). This shows that low frequency component of the sound from wind turbines is significant.
Why are we unwilling to accept the recommendation of the French Academy of Medicine to restrict location of wind turbines closer than 1500 metres to a home until an epidemiologic investigation into the possible medical effects of noise from wind turbines is carried out?
Is it acceptable that people already living near where wind farms are being installed are forced to be exposed to potential harm to their health against their will before the effects are fully known?
There are many examples showing that some people (and some animals) have been adversely impacted by noise from wind turbines – even when the noise is within acceptable dBA standards. Canadian Audiologist, Gordon Whitehead, has stated, “Some of the documented court challenges against wind farms around the world have used the rebuttal that if it (very low frequency sound) is inaudible, it cannot hurt you. This is untrue.” He points out “Legislation pertaining to wind farm generated noise and vibration does not extend beyond noise levels which have had the low-frequencies filtered out (dBA).” In conclusion he recommends that the government should write legislation for wind farms that addresses noise and vibration, including ground transmitted infrasound, and which addresses wind farm location in relation to existing housing?
Why should the MOE accept that standards of noise at receptor homes are not met on some 1000 to 1500 hours a year? This was presented to the MoE in 2006. In 2008 they agreed to study the “emerging science” while still approving more wind turbines under the old rules that have caused problems.
Why does the CANWEA proposed municipal zoning bylaw allow setback distances from homes 200 metres, when it is clear that the Ontario standard is not being met at greater distances?
Why do we not consider turbine noise on the “dBC” scale?
Why do we accept claims from proponents that wind turbines are like a “whisper” when this is far from true?
|Electrical system security||Popular belief is that adding many wind turbines scattered across the province ensures that the “wind is always blowing somewhere” and increases system security.||
Environment Canada weather data shows that on hot summer days, there can be little wind (calm conditions) simultaneously across Ontario at Thunder Bay, Sault Ste Marie, Wiarton, London, Goderich, Kingston, Ottawa, and Windsor. Diversity is not proven out by fact.
The annual wind report of the world’s largest wind system operator states, “The weather situation determines the wind level. Both cold wintry periods and periods of summer heat are attributable to stable high-pressure weather systems. Low wind levels are meteorologically symptomatic of such high-pressure weather systems. This means that in these periods the contribution made by wind energy in meeting electricity consumption demand is correspondingly low.”
Why does OPA accept the idea of diversity of location of wind to supply during summer peaks based on information supplied by CANWEA, the wind advocacy group, when Ontario weather data by Environment Canada shows hot still days with no wind across the province?
During hot summer days, much of central North America can be influenced by stable high-pressure weather systems that result in low wind. Is the experience of the world’s largest wind system operator (E.On-Netz, in Germany) not relevant to be considered as a factor?
|The Integration of Wind into the Ontario Electrical System||
A study conducted for the Ontario Power Authority (OPA) and Independent Electrical System Operator (IESO) by General Electric (GE) – the largest wind turbine manufacturer in North America, with data provided by the Canadian Wind Energy Association (CANWEA) – the industry advocacy group, claimed that it was possible to integrate 5000 MW of wind generation into the Ontario System in 2020 with a system peak of about 31,000 MW, and a system capacity of about 36,000 MW (5000 MW is about 14% of the 36,000 MW system capacity).
The OPA Supply Resources Discussion Paper uses the example of wind supplying at a 50% capacity factor during a summer peak day in August 2006 as a representative day. Further the OPA paper states “the capacity factor is generally insensitive to wind penetration level due to good wind geographic diversity”.
The Total German installed wind capacity of 16,394 MW was about 14% of a total German electrical system capacity of roughly 120,000 MW at the end of 2004. The German grid is also strongly tied to other European nations which makes it possible to transfer power to neighbours more easily than in Ontario. E.On-Netz, the system operator of over 40% of the wind generation “has more practical experience in integrating large amounts of wind into the system than virtually any their operator” (quoting the E.On-Netz Wind Report 2005.)
E.On-Netz states in their Wind Report:
IESO data for 100 days in the summer of 2006 June 1 to September 8 shows on 52 days Ontario wind turbines contributed less than 10% of their capacity factor at Ontario peak hour. Only on 9 days, did wind turbines have output at 50% of their capacity or higher at the peak hour.
Is it curious that a study conducted by a major wind turbine manufacturer, with data from CANWEA, showed the same fraction of Ontario’s electrical need can be supplied by wind as is supplied in Germany without identifying the problems that identified by the E.On-Netz Wind Report?
Why did the Ontario study not address the fact that Germany has strong interconnections to neighbouring states, which allow flexibility not available in Ontario? Why did the study not show that wind can only replace a small fraction of conventional resources, that changes in wind input can cause a major challenge to system operators, or that even simple grid problems can lead to significant failure in wind power production? Should the power consumer be encouraged that an integration study by wind proponents suggests high connection of wind resources in Ontario without identifying real experience of the world’s largest wind operator?
Is it curious that the OPA Integration study shows the example of wind contributing 50% of its capacity on one peak day, but is silent on the fact that wind contributed less than 5% of it’s capacity on hot days in May and June?
Should Ontario power consumers take comfort that the OPA integration study shows all 5000 MW of proposed wind generation contributing to the Ontario system required generating resources graph without recognizing that on some days there is little wind anywhere in the proposed wind capture area, according to Environment Canada data?
Why does the OPA reports use as an example a condition that applied on only 9% of the days in the summer, suggesting that wind turbine output of >50% was representative, when in fact on 52% of the days, output was actually < 10% during peak? Is this giving the right impression to report readers?
|Impact of wind turbines on wildlife||Wind proponents state wildlife effects have been surveyed and researched and are considered to be minimal.||
Wind turbine installations often are sited close to wildlife areas, as near woodlots at the back of farmer’s fields. Wildlife will preferentially avoid noisy areas, and will move to areas of lower noise. This results in loss of habitat.
Wind turbines are shown to increase the number of bat kills in Alberta and the United States – with hundreds of dead bats found. As bats are important insect predators, bat mortality imbalances the eco-system.
Siting of wind turbines too near flyways have also been found to result in raptor and other bird kills.
If wildlife move away from areas where wind turbines are located, and concentrate in areas away from the wind turbines, is this not loss of habitat?
Southern Ontario wildlife habitat areas are already threatened by other developments, and is the siting of wind turbines not just another pressure on wildlife?
Are not sustainable energy projects supposed to have minimal impact on all living creatures?
Revised July 28, 2008 by,
William K.G. Palmer, P. Eng.