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Wind power problems,
alleged problems and objections

Contents of this page...

Consider using one of the indices at the bottom of the page rather than this table of contents.

Introduction
Why do people object to nearby wind farms?

Specific wind power problems, alleged
problems and objections
  Valid wind power problems
  Noise and wind turbines
  Wind power not the answer to greenhouse?
  People driven from their homes?
  Compensation
  Do wind farms cause social conflict?
  Paucity of information from operators
  Lack of consultation?
  Lack of support for local community?
  Are wind turbines only short-term?
  Are wind turbines inefficient?
  Subsidies
  Do wind farms get government money?
  Timing of wind power generation
  Are wind turbines a fire hazard?
  TV reception and wind turbines
  Is solar better than wind?
  Leakage of oil
  Erosion of sites
  Bird deaths from wind turbines
  Fragmentation of bird habitat
  Pygmy bluetongue lizards
  Native vegetation
  General environmental concerns
  Roads and road damage
  Do environmentalists oppose wind farms?
  Do turbines frighten animals?
  Wind is variable
  Regional variation in generation
  Are wind turbines reliable?
  High temperature shut down
  Bats killed by wind turbines
  Honey bee problems?
  Power surges
  Can a wind farm change the local climate?
  Turbulence from wind turbines
  Energy consumed in wind farm construction
  Power used when turbine not generating
  CO2 released from wind-farm concrete
  CO2 and wind farms
  Visual objections
  Air navigation lights
  Water requirement
  Groundwater and wind turbines
  Wind farm effect on tourism
  Land values and wind farms
  Wind turbine litter
  Blade failure in wind turbines
  Are other countries abandoning wind power?
  Lack of transmission lines
  Does wind replace coal?
  How much electricity do wind farms generate?
  How does wind power compare to solar?
  Wind speed range of turbines
  Lightning strike
  Aesthetics
  Confidentiality
  Self-inflicted problems
  Denmark and wind power
  Too many turbines
  Generally popular, locally opposed
  Safety
  Cost of electricity
  Earthquakes and wind turbines
  Agriculture and wind farms are compatible
  Light aircraft and wind turbines
  Pressure in the ears
  Feeling of place
  Louder at a distance?
  Philosophy
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On other pages

Wind turbines save lives
Wind turbines and health
Wind forecasting
Energy return on investment
Wind in the Bush aims to be the most informative, comprehensive, and up-to-date pages on Australian wind power and wind farms.
The author is not beholden to any company, lobby group, or government. *



This page was previously a part of Wind Power in Australia;
and was created as a separate page 2008/08/26, modified 2014/10/13
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Contact: email daveclarkecb@yahoo.com

Using this page: some hints

This and most other pages of 'Wind in the Bush' are set out like reference books. There is a contents list at the top of each page and at least one index at the bottom of the page. Use these to find the subject you want, or use CTRL F to find words or phrases that interest you. You can also Google search all of Ramblings DC. All the main pages of 'Wind in the Bush' are listed at the top left of the Wind Home page and most are listed on each of the states' pages. The links in the text lead to supporting evidence or give more information. Feedback is welcome. Please contact me if you disagree with any statements on these pages, giving evidence supporting your points.


Introduction

Of course there are problems associated with wind farms, visual objections are understandable; some people like the look of wind turbines, some don't, that's human nature; "some people find wind farms pleasant and optimistic, or symbols of energy independence and local prosperity" (Wikipedia), others think that they are a blot on the landscape. In some people there seems to be little that elicits such a strong emotional response as a row of wind turbines on a nearby ridge (or the proposal to build wind turbines on a nearby ridge); they are necessarily very big and very conspicuous.

 

On this page, tables and graphs

Tables, Factors, wind vs solar | Relative efficiency of turbine | Carbon intensity | Abatement intensity

Graphs, Bird mortality | Bird deaths at Waubra | Wind power generation in one month | Power from all wind farms: combined 2012/01/15 | Power from all wind farms: individually 2012/01/15 | Power curve of a wind turbine | Relative efficiency of turbine | Turbines operable in commissioning wind farm | Emissions intensity | Wind energy contribution to SA power | Safety

 

What is important?

My opinion is of little importance. It is the facts and the research that matter, and the reasoning that can be based on them.
Beauty is in the eye of the beholder, truth is not. Truth is absolute.
 

The state of the debate

Having said that my opinion is umimportant, I will express it. As of January 2014 it seems to me that no intelligent, well informed, open minded person can doubt several things:
  • Anthropogenic climate change and ocean acidification are facts, are very serious and require an equally serious and determined response;
  • Wind turbines do not cause illness;
  • Wind turbines do not make a lot of noise;
  • Wind farms do not cause serious or lasting declines in the values of nearby properties.
 

Lies

One of the main purposes of these pages is to counter the lies told by the more unscrupulous of those who don't like wind power.
The variability of wind is one of its great disadvantages as an energy source. Bird and bat deaths caused by wind turbines are valid environmental concerns, and there are others (for alleged health problems from turbines see WindHealth), but wind energy has far less environmental impact than the fossil fuel powered generation that it replaces and is more economically viable than most currently available sustainable methods of generating electricity (although solar PV at least is fast catching up).

What follows is an independent point of view written by someone with no reason to either gloss over, or exaggerate, the problems and limitations of wind turbines and wind farms.

Sadly, in my experience many who are opposed to wind farms are woefully ill-informed and are not above lying or using facts in a misleading way to try to gain public support for their stance; many of them share with creationists and climate science deniers a willingness to twist the truth and ignore inconvenient evidence. And they are usually motivated by selfish and short-sighted desires including looking after their finacial backers in the case of many politicians, or chasing short-term financial gain in the case of the bosses of the fossil fuel industry. What they seem to forget (or just ignore) is that it is to all our advantages to take serious action to reduce our greenhouse gas production.

On the other hand it is true that some wind farm companies have acted unethically at times, with insufficient consideration for the people who are going to be living near wind farms at other times, and they generally emphasize the advantages and down-play the disadvantages of wind turbines.

A balance is needed.

If any reader believes that something on this page is wrong I'd be pleased to hear reasons and read supporting evidence; my email address is above. I started this page in 2008 and to the present (April 2013) while many people have provided helpful ideas for improvements and additions, no-one has pointed out any serious errors.

The problems that wind farms cause should be balanced against the problems that will arise if we do not build wind farms; greenhouse/climate change and ocean acidification will cause incomparably more environmental damage than wind farms do, and fire hazards, health problems and bird mortality will all be greater without wind farms. I have written a bit on the benefits of wind power and on the pros and cons of various methods of generating electricity elsewhere.

The reality is that our life-style in the early twenty-first century requires huge amounts of energy and wind turbines are one of the least environmentally harmful ways of generating electricity. Obviously wind turbines need to be built where the wind blows reliably and strongly. Perhaps those tempted to object to wind farms should consider whether they would prefer a coal-fired or nuclear power station nearby?

It is imperative that we greatly reduce our totally unsustainable rates of greenhouse gas production. Society is certainly not willing to give up private cars, air conditioning, computers, television, refrigeration, and all the other energy consuming equipment of the modern life-style (see What should be done), so we must build sustainable energy supply systems.

Why do people object to nearby wind farms?

 

Informative link

CSIRO: Societal acceptance of wind farms: Analysis of four common themes across Australian case studies; N. Hall, P. Ashworth, P. Devine-Wright. Seven case studies of wind farm development.
 
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It is perfectly reasonable for people to want to look after their own bit of the world; many people (probably particularly rural people) feel a strong attachment to the surrounding area and at least some can perceive wind turbines as intrusive and out of place.

Wind turbines are very conspicuous; they have to be. They have to be built in windy places; this usually means either on the top of a ridge or close to the coast, perhaps both. They are very tall. Being tall and on top of ridge-lines means that they will quite probably be visible from forty or fifty kilometres, and the fact that they are moving most of the time only makes them more inclined to catch the observer's attention. Anyone who takes a disliking to them will be frequently reminded of their presence.

It is also reasonable for people to object to a new source of noise.

 
Cartoon
This, in a nutshell, really is the main objection that most people have to wind turbines.
Cartoon credit Joe Heller
Envy also can be important when people see their neighbours getting substantial lease payments for the use of their land while they themselves get nothing. It has been pointed out that farmers who own 'bottom land', the fertile land on level ground or in valleys, have usually been financially better off than those who own the much less valuable, and less fertile, land on hills. The added income from wind turbine leases that has come to some of the farmers who own the hill land has changed this in a number of areas. This reversal of the financial situation has not greatly pleased some of the more small-minded of the 'bottom land' farmers.

Community-owned wind farms are much more common in Denmark than in Australia and experience seems to show that some degree of ownership makes people much more accepting of nearby wind turbines. It will be interesting to see how the local acceptance of the community-owned wind farms at Mount Barker in WA and Hepburn in Victoria evolves. (Especially in the latter, because it has many more share-holders and surrounding area is much more densely occupied.)
 

Why object to wind, but accept solar?

Very few people are opposed to solar power installations, even when these are on a neighbour's house, yet a number are bitterly opposed to nearby wind turbines.

A typical modern, utility-scale, wind turbine will generate about as much clean electricity as 2000 average roof-top solar installations (see here), so you would think that people who want action on climate change would support wind power.

Wind turbines make some noise, solar panels don't. Both are conspicuous, but in different ways; wind turbines change rural views, solar panels just change the appearance of people's roofs. Neither cause any health problems (except perhaps in the mining of the raw materials and manufacture of solar PV panels), unlike coal- and oil-fired power stations.

I would be interested in people's views on this question.

Perception

Dick Bowdler has been a noise consultant for 40 years. He has been a Fellow of the UK Institute of Acoustics since 1977. In his submission to the 2011 Senate inquiry into the impact of wind farms he stated that (quoting from the Senate report): "The major factor that determines the impact of a new noise source is perception." Referring to the UK experience with wind farms Mr Bowdler stated that if people feel that they are not being treated fairly, they will perceive, rightly or wrongly , that:
(My comments are in brackets)
Their lives will be blighted by these developments
(In fact there is little disadvantage in living near wind turbines)
They will gain no benefit
(We all benefit from reduction of greenhouse gas emissions)
They pay subsidies in the form of Tax
(In Australia at least there are few subsidies for wind energy, but there are subsidies to the mining industry. See Do wind farms get government money.)
They pay more for electricity
(Electricity price rises are mainly due to factors such as the cost of replacing old transmission infrastructure)
Developers make all the money
(Communities also benefit from wind farms)
Mr Bowdler concluded that "The result is that that people believe that government and developers are covering something up. This merely reinforces the views of those people who already believe that there is something mysterious about wind farm noise."

This subject is further covered under Generally popular, locally opposed. The benefits of wind power are discussed in Why support wind power. I have discussed people's motivations in supporting or opposing wind power developments elsewhere on this page, and their attitude to wind turbines in relation to unsubstantiated claims of ill-health due to wind turbines on another page.

Brown Hill Range Wind Farm
Looking north from the southern end of Brown Hill Range Wind Farm
 
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Specific wind power problems, alleged problems and objections

 
Altered 2014/06/03

Valid wind power problems

There are many claimed, but unjustified, problems with wind power; much of this page deals with these claims. This section lists some of the real problems and will redirect the reader elsewhere (mainly on this page) for details. The problems can be placed into several catagories.

Noise problems

Turbines can, under some circumstances be heard at distances at least as great as 2.5km. While the sound is not loud, some people find it annoying, and at smaller distances (perhaps 1km or less) it may stop some people from sleeping and lead on to anxiety and stress in some people; this, in turn, can lead to health problems.

Power availability and transmission problems

The wind does not blow all the time. When the wind is not blowing wind turbines do not generate power. At times of peak electricity demand winds tend to be lighter than average.

When any type of generation is not in the same place as consumption there is the need to transmit the power from one place to another. This requires very expensive high capacity, high voltage, transmission lines. For example, South Australia has much more wind power per capita than other states; if wind generation is high and consumption is low in SA then the power must be sent interstate.

Inequible spread of financial benefit

In early 2013 the farmers who hosted wind turbines were typically paid at least $10 000 per turbine per year by a company runing a wind farm. Their neighbours, who did not host any turbines, received no direct benefit. This, of course, led to envy and resentment.

Trust Power have offered a financial solution for this at their proposed Palmer Wind Farm in South Australia. They are offering annual cash payments to nearby residents. Another, perhaps preferable, arrangement would be a gift of shares in the wind farm, as then the receiver would have an interest in the running and profitability of the wind farm.

Of course, even without the sort of direct benefit Trust Power are talking about the neighbouring people may benifit indirectly, for example by the community funding that most wind power developers set up, or from contracting or employment etcetera, but there has not generally been a good balance of financial advantage in the immediate vicinity of a wind farm.

Invasion of space problems

Some people move to country areas because of the relatively undeveloped feel of the place. Others have lived in an area for a long time and have developed a feeling of attachment to the place as it is and understandably might not think it will be improved by a row of wind turbines on nearby hills.

Aesthetic problems

This is related to the invasion of space problem above. Some people like the look of wind turbines, others hate them; it is a matter of personal preference – 'beauty is in the eye of the beholder'.

The life of a wind turbine is expected to be around 25 years. What happens to it when it reaches the end of its useful life? Some wind farms in the USA have simply been abandoned, leaving broken and rusting towers in conspicuous positions. (No wind farm has ever been abandoned in Australia.)

Environmental problems

There are a number of environmental concerns that are perfectly valid. Wind turbines do kill some birds and there are problems involved with the necessary distruction of remnant native vegetation and possible erosion problems connected with the building of roads and hardstands. It seems that wind turbines kill a worrying number of bats, but there is a lack of research on this; birds are pretty and visible, bats are rarely seen and are not 'cute and cuddly'.

Rare earths

At least some wind turbines (and a great many other industries) use magnets based on a group of elements called rare earths; the mining of rare earth minerals in third world countries has been carried out with little concern for environmental damage. Much of the world's rare earths come from China, see the Guardian Weekly for a description of some of the environmental damage there.

Problems to do with poor practice

  • Some wind farm developers have been less than honest when they have told people, for example, that they will not hear the turbines.
  • Some developers make little effort in keeping the local people informed about the development.
  • Some wind farm developers place confidentiality clauses in contracts with the turbine-hosting landowners that limit the landowner's freedom of speech in matters relating to the wind farm. This causes mistrust and resentment and places the whole industry in a bad light. Secrecy should be avoided, and limiting freedom of speech may well be unethical, certainly if the organisation doing the limiting does not freely admit that it is limiting the freedom of speech of the landholders.

Social disruption

Sometimes, when a wind farm is proposed, comunities are split into supporters and opponents. Occasionally bad feeling arises. In my experience this is more often due to people spreading misinformation about wind farms than being due to the wind farms themselves. For example, there has been no social disruption due to the Clements Gap and Snowtown wind farms (both near my home) because there was no vocal opposition.

Other problems

Wind turbines can cause problems with television reception and cause interference to radar installations. Shadow flicker can be annoying when the shadow of moving turbine blades fall on a house at certain times of the day and year. Wind turbines limit where aircraft can go and this can pose problems for agricultural aircraft services. Fires in wind turbines, while rare, are very difficult to fight.


Finally, we must consider where we are going to get our energy if we do not build sustainable energy infrastructure such as wind farms. Very few people will be willing to get by with substantially less energy and using fossil fuels or nuclear power comes with far more problems than does wind power. We must do all we can to slow climate change. "You cannot make an omelet without breaking eggs."
 
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Is wind power the answer to greenhouse and climate change?

Some people, David Bellamy is a vociferous example of this group, object to wind farms saying that they are not the answer to greenhouse. Their problem seems to me to be a too high expectation. Wind power is not the answer, it is however a part of the answer to a very big problem, the biggest single problem Man has faced to now.

The Australian Electricity Generation Report 2008 from The Climate Group stated that South Australia was the only eastern state to reduce its greenhouse gas production in that year (a fall of 6%); this was mainly thanks to wind power taking the place of some of the fossil-fuelled generation. More recent reports, including one in 2011 by the Australian Energy Market Operator (AEMO) showed that this trend has continued.

Our society must not confine itself to building wind farms, we must also:

  • Reduce wastage of energy and unnecessary energy use; this will require a massive change in thinking for most people;
  • Walk or ride bicycles more, not only will it save greenhouse gasses, it will improve our health and make our cities and towns more pleasant places in which to live;
  • Develop other renewable energy sources;
  • Modify our electricity supply system to make it more compatible with sustainable electricity;
  • Reduce unnecessary use of private cars – use cars that are no bigger than we need, move toward highly efficient cars such as hybrids, or use electric cars powered by green electricity. Again, an enormous change in priorities and thinking is needed;
  • Make our housing less hungry for energy and run our houses with more consideration given to power consumption;
  • Improve public transport;
  • Cut down on unnecessary consumption;
  • Cut down on unnecessary packaging;
  • Reuse rather than throw away;
  • Recycle where we can't reuse.
Many more examples are given in What Should Be Done?

Substantially increasing the price of energy would probably be the simplest and most efficient (but difficult to sell politically) way of achieving most of the above points.

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Altered 2014/07/20

People driven from their homes by wind turbines?

 

Professor Simon Chapman's investigation

Simon Chapman's paper on this claim has been published in the peer-reviewed journal Noise and Health.

It included:

The statement that "more than 40" houses have been "abandoned" because of wind turbines in Australia is a factoid promoted by wind farm opponents for dramatic, rhetorical impact. Other considerations are often involved in abandonment unrelated to the claims made about wind farm noise.
Professor Chapman reported that there seemed to be no "cases of true 'abandonment' in the sense that the families concerned 'fled' there house, unable to sell it."
Dr Sarah Laurie (a vocal supporter of the claim that wind farms make people ill), and others, have claimed that some homes close to turbines in Australia (at Toora, Waubra and Waterloo) have been abandoned due to the owners being unable to live with the noise from the turbines or being made ill by the turbines. However, does this claim stand up to critical scrutiny? We know that wind turbines don't make much noise and wind farm workers don't have any problems. Were there other reasons to explain the abandonment?

In the Ballarat hearing of the Senate inquiry into the impact of wind farms on land values (2011/03/28) Councillor David Clark of the Pyrenees Shire Council said:

"We did a revaluation in early 2010, so six months after Waubra wind farm was operating. We did not see an effect on commercial agricultural land. It had moved up and our belief is there were other factors driving the price of that. We did not see an effect on the nearby township of Waubra. Prices again had moved up in the case of that township, which is about 1.2 to 1.5 kilometres away."
Two years later, in the Pyrenees Shire Council Meeting Minutes, General Revaluation of Properties, 2012; of ten areas listed under 'Residentual Properties' Waubra shows the largest rise, 10.1%. The average change of the remaining nine areas was a rise of 2.9%. The valuations are done every two years.

If people are being driven from their homes by the Waubra Wind Farm one would expect a big decline in land values; the fact of the matter is quite the opposite.

 

My own experience

I have slept beneath operating wind turbines on a number of occasions and have had a good night's sleep every time.

A law of physics

Sounds, or anything else emanating from a turbine, would be expected to follow the inverse-square-law of physics; twice the distance, a quarter the strength; three times the distance, a ninth the strength; etc.
In September 2011 I was sent a map of a part of the Waterloo wind farm area showing the line of the turbines and the 'abandoned houses'. (The map was displayed here, but on 2012/02/10 the person who sent me the map asked me to remove it for security reasons. I have done so.) A little consideration of the map raised some questions. Not one of the houses was closer to the turbines than 3.5 km; three of the houses involved were in Waterloo township, 3.5 kilometres from the turbines, and the forth was 4.5 km away.

The greatest distance from which I have ever definitely heard turbines is 3 km, and then only once and in ideal conditions. I have visited Waterloo township about ten times while the turbines were operating and have never heard the turbines from the township.

So how could turbine noise be driving people from houses at such a distance that the residents would rarely hear the turbines, even when they were outside? Could it be that people were moving out of Waterloo because they wanted to live in a larger town with more services (there are no shops in Waterloo)?

 
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There are laws in South Australia, and probably all other Australian states, about permissible noise levels from wind turbines; so in cases where noise levels were excessive the owners would have a legal right to compensation. (The Waterloo Wind Farm has been found to be compliant with the SA EPA guidelines.)

 

Speculation – fraud?

Are some of the people claiming noise and/or health problems actually wanting to move to a more desirable location and get a higher amount of compensation for their houses than the normal market price? Some may hope to force a wind farm company to buy their home at a higher-than-market price by claiming to have been made sick. (For example, in the Waterloo case, I have been told that at least one of those who 'was driven from his home' had previous plans, quite unrelated to the wind turbines, to leave.)
Few people want to live in small country towns in Australia; they lack the services and shopping facilities of the cities and larger country towns. Older people don't want to live a long way from medical and hospital services; young people find few employment oportunities in small towns. For decades small country towns have been tending to get smaller. Homes in small country towns often have very low market values; similar houses in nearby larger country towns have much higher values.

This also relates to the question of Land values and wind farms; plainly, if a house truly had been abandoned due to noise nuisance, its value on the market will drop substantially.

There are many small towns in Australia, so it happens that wind farms will often be within a few kilometres of a small town.

Abandoned homes at Waterloo?

Waterloo is a very small country town in Mid-North South Australia. It has no shop and no hotel. It has been claimed that some people have been driven from their homes in and near Waterloo by the turbines of the Waterloo Wind Farm. Well before the wind farm was built it would have been very hard to find a buyer for a house in Waterloo.

There may well be special factors involved in the vacant houses at Waterloo; perhaps these have nothing to do with the wind farm?

At the Clare hearing of the Parliamentary Committee on Wind Farms, a wind farm opponent, John Faint, was asked "Are there likely to be factors other than the wind farm that have led to the decline of the local population?" (Question No. 886) He answered:

"No. Farms have become bigger, so if the farms have been sold they are usually bought by the neighbours, so families are lost that way. That is probably common all over the state. But the only other industry in Waterloo has been a quarry. That employed a few locals, but that has been leased out to a company called Fulton Hogan, and they are not operating there at the moment because they are a big company and they go where the work is. There is probably one permanent person there and a casual, and there would have been perhaps 20 people there at one stage. That would have helped the local community, but that is probably it, the main thing. However, as I said, the wind farm has not created any [jobs]."
Previously (question No. 818), another wind farm opponent, Ms Wanda Allott, had said:
"When I first moved there [Waterloo] virtually every second house was empty. After five years virtually every house was full. ... The wind farm comes and within six months people are leaving. ... and now the town is virtually empty again."
The Waterloo houses could well have filled because of jobs at the quarry (Mr Faint said that it was the only industry other than farms). And Mr Faint said that the quarry jobs had disappeared; isn't it very likely that that is why people have left Waterloo? (Of course Mr Faint is wrong to say that the wind farm has not created any jobs. There are a number of people employed in operation and maintenance.)

A good night's sleep at Waterloo

 
Camp at wind farm
Camping under a wind turbine at Waterloo Wind Farm; my swag is just visible behind my car

I went to the Waterloo wind farm on the evening of 2012/02/10 and set up my swag beneath one of the turbines. The number of kangaroos on the ridge impressed me; I must have seen at least eight, including a small joey. I also saw a pair of wedge-tailed eagles circling near the turbines. All were apparently in good health.

The wind varied from a moderate to a stiff breeze, so the turbines were operating all night. While I could plainly hear the turbines whenever I woke at night, I had no problem at all in getting a good night's sleep. Right at the foot of the turbine the sound of the turbine gear-box dominated the sound of the blades as they passed through the air. I noticed that when I moved away 100m or more all I could hear was sounds of the blades.

When passing through Waterloo in the evening I stopped my car and listened for the turbines. I could not hear them. The breeze in the nearby trees was making a fair amount of sound. In the morning I again passed through Waterloo and stopped. There was still a stiff breeze on the ridge where the turbines were, but very little air movement in Waterloo. I thought I might just be able to hear the turbines, but could not be sure.

Some people might well find the sound of turbines annoying and, if they were very close to the turbines, I could believe that they might be, unlike me, kept awake by the sound; but I totally fail to understand how people could find turbine sounds objectionable at distances of several kilometres.

Also see Good night's sleep under wind turbines where I write about sleeping under and near other turbines. The dose-response relationship is also very relevant to distance from turbines.



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Edited 2013/07/14

Compensation

When, how, how much, and for what should people who suffer in one way or another from wind turbines be compensated? This is a very difficult subject and one that can only be covered in a very superficial way on a page like this.

Natural justice demands that people whose amenity has been impacted by noise or some other problem to do with turbines should receive some sort of compensation. But if one person is compensated, how do you stop others who may be similarly placed in relation to turbines, but not have any real problems with them, jumping on the band-wagon and demanding similar compensation just because they think they can get it? How do you treat people who might honestly, but erroneously, believe their health has been impacted by wind turbines? Leave it to the courts?

The power given to Victorian householders to veto any proposed turbine within 2 km is not an answer because all the power is with the householder and none with the wind farm builder; there must be a balance. Many people live perfectly happily with wind turbines much closer than 2 km.

Should compensation be based on recorded noise levels, the difference between ambient noise and wind turbine noise, or something else? Ideally, it should depend on the true impact on the individual; but how to measure that?



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Altered 2013/05/07

Do wind farms cause social conflict?

It has been alleged that wind farms divide communities or that they "cause significant, long-standing social conflict and division within rural communities." This is questionable.

There was very little, if any, social conflict associated with wind farm construction in Australia until about 2008; around the time that the anti-wind farm lobby started to become active.

Is it the wind farms, or some inept wind farm developers who get on the wrong side of the local people, or even unethical wind farm developers; or is it wind farm opponents, or is it those who tell lies about wind farms and wind energy, or even climate change deniers – who deny that there is any need to change to renewable energy at all – who cause social conflict?

 

Misinformation and lies cause social conflict

Wind farm developments have few disadvantages for a hosting community and many benefits, but some people have been very effective in spreading misinformation about wind farms while others have been very effective in causing quite unjustified fear regarding wind turbines and health.

These people produce fear and misconceptions about wind farms and this can then lead to social conflict when a wind farm is proposed.

Sweeping generalisations and unjustified claims

One wind farm opponent in the Darlington area of Victoria has made credible claims of unscrupulous behaviour by one wind farm developer. He goes on to claim that the whole industry is corrupt and wind power is a scam.

There are many people involved in the wind power industry, it would be surprising if they were all honest and ethical people. One or two unethical developers is not proof of a corrupt industry. Even more, the presence of some bad people in the industry is not evidence that there is anything wrong with the principle of renewable wind energy.

Another opponent on the Yorke Peninsula of South Australia claimed that the local wind farm developer's describing a project as 600MW when it would generate an average of around 200MW was evidence that wind farm developers were pathological liars. (It is a matter of capacity factor; for wind power in SE Australia it is about 34%. The CF for solar PV power is about 18%, so a 600MW solar power station could be expected to generate an average of around 110MW.)

In those ocasions when disagreement and sometimes conflict have arisen, from my experience it is most often those who spread misinformation and unfounded rumours about wind turbines who have been the cause. For example, there was no social conflict when Wattle Point Wind Farm was built in 2005, or when Snowtown Wind Farm was built in 2008; but there was conflict when another wind farm, the Ceres Project, was proposed in 2012 between Wattle Point and Snowtown. An active and particularly dishonest opposition group played a big part in this.

I emailed Frank Brennan, CEO of the Wattle Range Council where both the Canunda and Lake Bonney wind farms have been built (the latter being the biggest in the country as of mid 2008). He replied "There has been no 'significant and long-standing social conflict' from the lake Bonney or Canunda Windfarm developments – to the contrary there has been significant local community support for these projects."

The Central Western Daily (Orange) reported on 2011/12/05 that Blayney mayor Bruce Kingham stated that "In the 11 years since the [Blayney] wind farm [was built], we have had not one complaint".

At the sod-turning ceremony, Snowtown Wind Farm Stage 2, on 2012/10/25, Mayor of Wakefield Plains Council, James Maitland, said that he "was not aware of any negativity" regarding the project.

Clements Gap Wind Farm, 15 km from my home, has not caused any social conflict that I know of.

On the other hand there is social conflict concerning wind farms such as Mount Bryan, a little further to the north-east, and Waubra, in Victoria.

So, there have been a number of wind farms built without social conflict. Social conflict only happens when people oppose wind farm projects and opposition often arises in response to misinformation about wind power.

The arguments for and against proposed wind farms do, no doubt, cause enmities. This is unfortunate, but probably unavoidable; many people see wind turbines as a part of the answer to the greenhouse/climate change problem, others see them as a blight on the landscape. The fact is that any industrial development, especially a conspicuous one, is likely to lead to disagreement in some cases.

Disagreement is not conflict. People within a community have always disagreed about many things. So long as the discussion is rational and unemotional there is no need for real conflict.
 
Don Quixote de la Twenty-first Century
Don Quixote
I saw this cartoon in ReNew and couldn't resist copying it here. The original was aimed at the NSW Government which, as well as cutting the solar power feed-in tariff, has shown anti-wind power sentiments.
Bill Gresham is a sixty-plus year-old who feels so strongly about climate change and renewable energy that he did the 328km Walk for Solar from Port Augusta to Adelaide in September 2012. I met him there.

Conflict – my own experience

It is not the wind farms that cause the social problems, it is the unreasonable and unjustified opposition to the wind farms and irrational fear of turbines that causes conflict. A long-time friend of mine developed the view that wind turbines were making some people sick and that these people were not being taken seriously. After a short discussion the friend refused to consider further argument on the matter.

Climate change is the greatest environmental and ethical challenge to 21st century society; changing from fossil fuels to renewable energy is one of the actions that is essential to combating climate change. I can accept that some people don't like wind turbines on aesthitic grounds, I agree that there are some genuine and valid problems with wind farms; but I refuse to turn a blind eye to people who tell lies about wind turbines.


Envy

Farmers who have turbines on their property receive thousands of dollars a year per turbine from the wind farm operators; some of their neighbours, having no turbines on their land, may receive no direct payments at all. This results in very understandable envy in at least some people.

The neighbours who do not have a direct share in the largess must, at least in some cases, feel that they are having to accept the visual impact, sometimes hear the turbines, and even believe that their health is being impacted, while gaining nothing.

In many cases the whole community benefits, due to jobs, work for contractors, accommodation demand, not to mention community funds, but these may not be seen as benefiting those neighbours who see themselves as missing out.

A specific case in which envy seems to be a major factor in the development of opposition to a wind farm is the Ceres Project on SA's Yorke Peninsula, where some potential turbine hosts demanded more money than the proponent was willing to pay. After they were passed over they had a big part in setting up the opposition group Heartland Farmers.

This envy is related to NIMBYism, and both perception and attitude to the wind turbines are involved.



Paucity of information from operators

 
AGL shop
AGL "Information Centre", Burra
Supposedly open Monday to Friday 1100 to 1500hrs. (Note the big sign painted on the window stating "Now open", visible 24 hours a day.)
When I was there, 1100 to about 1330hrs Friday 2009/02/13, there was no sign of life (but it was open on a visit in 2013, and the lady was very informative).
To do justice to AGL, their SA Manager of Power Development, Tim Knill, has been very helpful.
Unfortunately, while some businesses involved in wind farms in Australia make a serious effort to provided information, others don't trouble. There are some types of data that few wind farmers are willing to make public, for example few wind power operators routinely makes public the capacity factor (the percentage of the rated generation that is actually achieved) of their farms, nor do any publish the day-to-day, month-to-month, or year-to-year generation figures (see graph below). The cost of wind power is contentious; wind farm opponents like to talk about how expensive wind power is, a claim that is not easily refuted due to a general lack of data available to the public.

 
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Many wind farmer's Net sites give minimal data and are rarely updated. Internet sites are easily and cheaply updated and the operators must have the information. One wonders why they are so stingy about sharing it.

Ignorance of the facts of wind power is obvious in many wind power opponents. For example, I have read from opponents several times that wind farm construction uses huge amounts of water; this is not true, but it is difficult to get actual water consumption figures from wind farmers.

The companies that do the earth works for wind farms seem even less comunicative than the wind farmers themselves.

Those companies that make little or no effort to inform Australians on the facts about the wind farms that they are proposing, and wind power in general, are doing a disservice to informed discussion and, in the long run, are letting down their industry.

Several of those people in the wind industry who have provided information for these pages have done so on the condition that I don't disclose their names, several others didn't want me to publicise their email addresses. In the interests of credibility I would like to be able to attribute the data on these pages, but the lack of openness in the industry makes this impossible in some cases.
 
Wind power generation graph for August 2007 from Wonthaggi, Victoria
Wind 
graph
Acknowledgement, Wind Power Pty. Ltd.
So far as I know, this sort of data is no longer available from any wind farm in Australia (although it can be obtained from the AEMO).

Some in the industry only provide information in the form of PDF files that are very poorly indexed, so until they are downloaded it is very difficult to know what they might contain.

It was in response to this lack of easily accessible information that in late February 2008 I started expanding my wind farm pages – which previously had mainly concentrated on wind farms in South Australia – to cover the whole of Australia.

Unbiased studies into bird and bat impact, the effect of wind farms on property values, noise, sunlight-chopping, etc. should also be made easily and freely available. This is the responsibility of government as well as the wind industry.

Finally, I should say that there are many individuals in the wind power industry who have been very generous in providing me with information. It seems that those in charge of public relations are most at fault.



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Updated 2011/08/23

Do wind farmers consult sufficiently with local communities?

A resident of Hallett, where AGL has several wind farms, complained to me that AGL had very little consultation with the local community before committing to build their wind farms. I cannot say whether this complaint was justified.

In my own experience Pacific Hydro who built the Clements Gap wind farm in the Crystal Brook area, consulted widely with the local communities. Roaring 40s (and then TRUenergy), the developers of Waterloo, Stony Gap, and Robertstown wind farms also seem to be making a good effort to inform the local people.

There have been complaints that the wind farm companies explain rather than consult; that they tell people what is going to happen rather than ask what should be done. In my experience this is true. But wind turbines must be built in the best places to build wind turbines; there is not a huge space for compromise if a wind farm is to be economically viable.

Communities are made up of individuals. Each individual who lives near a proposed wind farm will have an opinion on where turbines should, and more to the point, should not be built. Aesop said something to the effect of "He who tries to please everyone will please no-one".

The people of Australia demand copious amounts of electricity. The climate change problem demands that we reduce our carbon intensity. Wind power is one of the most technically advanced and competitive forms of renewable energy available. Of course the concerns of the local people should be listened to, and if there are consensuses to be found, they should be complied with if this is a practicality, but ethically, isn't there an obligation to aim at the greater good – of everyone and the world as a whole – rather than sacrificing the greater good in order to try to please all the local people?



Wind turbines at North Brown Hill Wind Farm
Turbines and fog
A light breeze was clearing the morning fog


Do wind farmers support local communities?

There are several wind farms near Hallett (Mid North South Australia). A resident of Hallett complained to me that AGL, the owner of the Hallett wind farms, has not provided any financial or other support for the Hallett community, while admitting that support was given to Jamestown, another nearby town.

I inquired about this, but did not receive a response (AGL have not responded to a number of my inquiries).

Most wind farmers do support the local community. For example, Pacific Hydro, which has built a wind farm near my home town, Crystal Brook, gives $50 000 each year for community projects for the life of the wind farm. Also there are many commercial gains to a community during wind farm construction: lease payments to land owners, work for local contractors, business for hotels, restaurants and providers of accommodation, etc. Once finished there are jobs in maintaining the wind farm.

Also see community funding by wind farmers.



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Edited 2014/02/22

Wind turbines are as long-term a source of sustainable energy as anything else

A complaint about wind power that came up in conversation was that wind turbines have a short life and that we should be looking for long-term answers to energy supply, such as solar.

 

New research on old turbines

Science Daily: 2014/02/19 "Claims that aging wind farms are a bad investment blown away by new research"
In fact modern (~2012) wind turbines, including the blades, have an expected life span of around 20 to 25 years; typical solar photovoltaic panels are guaranteed for twenty years, and then with a decline in productivity written into the guarantee. Solar thermal or concentrating photovoltaic systems have not been around anywhere near twenty years so their life-spans are unknown, but I would think they would be unlikely to last any longer than 25 years, at least without major rebuilding.

It is quite possible that wind turbines will last longer than 25 years, but the technology is improving quickly and typical 25-year-old turbines have become obsolete, Salmon Beach, Esperance, WA, for example, became obsolete in 15 years.

Other sustainable energy systems, tidal, wave and hot-rock geothermal have not yet reached ages such as twenty or 25 years, but again they would be unlikely to last any longer than that. Hydro-power stations last longer than 25 years, but even they must need major maintenance at periods of a decade or two.

There is no one solution to our current dilemma, reducing energy consumption should have a higher priority than building wind farms, but wind power is just as much a long-term solution to the sustainable energy problem as is any generation technology.



 
Altered 2013/03/15

Efficiency of wind turbines

 

Repetition in ignorance

Wind farm opponents hear something like "wind turbines are inefficient" and then repeat it without bothering to check on its veracity. All the statement shows is the ignorance of the person making the claim.

Justifying statements can be a lot of trouble. I've read and written reams in an effort to justify what I write. It's a lot easier to just repeat something that you hear and like and hope that someone will believe you.

One of the most oft-repeated fallacies about wind turbines is that they are inefficient. A study in mass-psychology could usefully be based on this phenomenon. It seems that people who are opposed to wind turbines hear or read that they are inefficient and then repeat the lie without checking on its veracity. There is no meaningful sense in which wind turbines could be called inefficient.

Often these people are confusing efficiency with capacity factor, but in any case it is worth giving some thought to what could be meant by efficiency when applied to wind turbines.

The Oxford English Reference Dictionary defines efficiency as: "The ratio of useful work performed to the total energy expended or heat taken in."

Efficiency is very important in the case of fossil fuel power stations because fossil fuels are a finite resource – once we use them they are gone – and when burned they produce carbon dioxide and other substances that kill people and cause climate change and ocean acidification; so it is very important to get as much electricity as we possibly can per tonne of fossil fuel. A typical ratio of 'useful work' (electricity generated) to 'heat taken in' for fossil fueled power stations is about 1/4; ie; 25% efficiency.

 

Different meanings to different people

The main text discusses efficiency in the energy-in vs energy-out sense. Another sense in which wind turbine efficiency has been used is in dollars per unit of greenhouse gas abatement.
What about the efficiency of wind power? Going back to the definition – there is no 'energy expended' or 'heat taken in', so the ratio is 1/0! Electricity is generated, but nothing is consumed; infinitely efficient! (This is not quite true; if the wind isn't blowing wind turbines do consume a little electricity to run various equipment, and of course the turbines take energy from the wind.)

It could be said that before windmills and wind turbines all the energy in the wind was being wasted – that is, the efficiency of converting wind energy to useful work was 0%. The more wind energy that is converted to useful energy, including electricity, the more we improve on that. If we don't convert the wind into useful energy it could be called a wasted resource.

At the most wind turbines convert somewhere around 40% of the power of the wind that passes through them into electricity. The energy of the wind is in its movement; to take all the energy from the wind would be to take all the movement from the air; with a little thought you can see that this would be quite impossible. The theoretical limit to the amount of power that a turbine can take from the wind is 59%; this is called the Betz limit.

 
Power curve of a Suzlon S88, 2.1 MW turbine
Power curve
Data from Suzlon

Defining efficiency in the case of wind turbines

The efficiency of a wind turbine could be defined as the electrical energy generated divided by the power that has been taken from the wind. In what follows, efficiency is considered to be the electrical energy generated divided by the power available from the wind.

What is lost if wind turbines take relatively little energy from the wind?

Does it matter that wind turbines do not take all or most of the energy from the wind that passes through them? The answer has to be no. Wind is a renewable resource, we can never use it up, and the process of taking energy from it produces no pollution. If a particular turbine takes little energy from the wind that passes through it, then the velocity of that wind is not much reduced. No harm is done. (The turbine might produce turbulence, this has environmental implications and has been discussed elsewhere on this page).

The amount of power generated by actual Australian wind farms is given at Power generation of wind farms.

Energy in wind

 
Relative efficiencies of Suzlon S88, 2.1 MW turbine at increasing wind speeds (note definition of efficiency above)
Wind speed (m/sec)Power
generated (kW)
Relative efficiencyComment
200Wind too slow
4140.13 
63120.88 
75460.97 
88401.00Maximum efficiency
911800.99 
1015350.94 
1220370.72 
1421000.47Full power
1621000.31 
1821000.22 
2021000.16 
2221000.12 
2421000.09 
2600Shut-down
Based on power-curve data from Suzlon
and the cube law of wind energy
From Newton's laws of motion we can deduce that the amount of energy in any mass in motion is proportional to the square of the velocity of that mass. In the case of wind power, we must also take into account the fact that when the velocity of the wind doubles the mass of air moving through a turbine in any given time also doubles. So the amount of energy available to a wind turbine is proportional to the cube of the wind speed.

Consider the power curve shown in the graph above (and the table on the right). It shows that when the wind velocity rises above 14m/sec the turbine does not generate more electricity, in spite of the fact that the energy in the wind increases.

We can calculate (from the cube relationship mentioned above) that this turbine is at its most efficient, in the sense of taking the greatest proportion of the available energy from the wind, at a wind speed of about 8m/sec. We can then calculate how its efficiency varies at other wind speeds, relative to that. This is laid out in the table on the right.

Note that if this wind turbine is 40% efficient at a wind speed of 8m/sec then it is only 3.6% (0.09×40%) efficient at a wind speed of 24m/sec. That is to say that it takes proportionally very little energy from the higher speed winds.

 
Relative efficiencies of a Suzlon S88, 2.1 MW
turbine at a range of wind speeds
Relative efficiency
Data from the table above
The graph at the right shows that a typical modern turbine takes the greatest proportion of available energy from the wind at a wind speed of 8m/sec. At this wind speed the turbine is probably taking about 40% of the available energy from the wind. If we call this a relative efficiency of 1.0 the relative efficiencies at other wind velocities can be calculated (efficiency being defined as the proportion of the available energy being taken from the wind).

So while the turbine does not reach its maximum rate of electrical generation until the wind speed gets to about 14m/sec, it is at its maximum efficiency at much lower wind speeds.
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An article by wind farm opponent David Libby in which he calculates an efficiency of 24% for a particular wind turbine

The piece below was titled Absurdly Inefficient and published on the Net site Stop These Things, 2012/12/30. The arithmatic seems to be correct, but the conclusion strange to say the least.

Libby calculates that at a wind speed of 14m/second a particular turbine will generate 2MW of electricity while the total power available in the air passing through the turbine is 8.5MW (giving an efficiency of about 24%, very similar to that of coal-fired power stations). What he does not explain is why the 'failure' of the turbine to take a larger proportion of power from the wind is any sort of problem. Much of the power that was in the wind remains in the wind – is this bad?

Wind power opponents have a hang-up about wind turbines being inefficient, but, so far as I know, not one has ever explained how this claimed inefficiency is a problem.

Absurdly Inefficient by David Libby

Wind is made up of moving air molecules which have mass – though not a lot. Any moving object with mass carries kinetic energy in an amount which is given by the equation:

Kinetic Energy = 0.5 × Mass × Velocity2

where the mass is measured in kg, the velocity in m/s, and the energy is given in Joules.

Air has a known density (around 1.23 kg/m3 at sea level), so the mass of air hitting a wind turbine (which sweeps a known area) each second is given by the following equation:

Mass/sec (kg/s) = Velocity (m/s) × Area (m2) × Density (kg/m3)

And therefore, the power (i.e. energy per second) in the wind hitting a wind turbine with a certain swept area is given by simply inserting the mass per second calculation into the standard kinetic energy equation given above resulting in the following vital equation:

Power = 0.5 × Swept Area × Air Density × Velocity3

where Power is given in Watts (i.e. Joules/second), the Swept area in square metres, the Air density in kilograms per cubic metre, and the Velocity in metres per second.

The turbine has a rotor blade diameter of 80 metres and so the rotors sweep an area of PI × (diameter/2)2 = 5026 m2. We know the air density is 1.23kg/m3. The turbine is rated at 2MW in 30mph (14m/s) winds, and so putting in the known values we get:

Wind Power = 0.5 × 5026 × 1.23 × (14 × 14 × 14)

...which gives us a wind power of around 8,500,000 Watts. Why is the power of the wind (8.5MW) so much larger than the rated power of the turbine generator (2MW)? Because industrial wind turbines are absurdly inefficient piles of junk.

Mr Libby has calculated that this particular wind turbine is 24% efficient. What harm is being done due to the wind turbine being less than 100% efficient? What is lost? Where is the problem?

 
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Would Mr Libby prefer polluting coal fired power stations that are also around 25% efficient? Perhaps nuclear (typically around 30% efficient)?

The 24% efficiency that Mr Libby calculated is similar to the efficiency of coal-fired power stations and far ahead of the 15% efficiency of internal combustion engine-powered cars in converting the energy in the fuel into useful power delivered through the wheels.



 
Edited 2013/11/17

Subsidies – in regard to wind power

See also Do wind farms get government money?

Fossil fuels are dug or pumped from the ground and burned to generate electricity; it's very simple and very dirty. The industry receives a huge subsidy in the form of a license to dump its toxic wastes into the atmosphere.

 
Subsidy to mining
Facebook, 2013/01/21
Also see Paid to pollute
 

More subsidies to coal

The Federal Government funding for the Hunter Valley Corridor Capacity rail upgrade, to move coal from mines to the coast, cost taxpayers $855 million. (See Beyond Zero Emissions, Is Coal Mining Harming Our Health?)

The Victorian government is to spend $4.2 million to strengthen the brown coal mines in Gippsland following flooding; 2013/05/08.

In addition the fossil fuel industries receive huge amounts in open and hidden subsidies:

  1. The International Monetory Fund (IMF) produced a report on January 28th, 2013 that gave the post-tax subsidies in 2011 for petroleum products, natural gas and coal as a percentage of gross domestic product (GSP). Figures for Australia are below:
    Fossil fuelPercentage of GDPUS$ (billions)
    Petroleum products1.1117
    Natural gas0.132
    Coal0.558
    From page 57 of the report

    The report was titled Energy Subsidy Reform: Lessons and Implications. Australia's GDP in 2011 was about US$1500 billion; the dollar values above are calculated from this and the figures given in the report.
  2. The Australia Institute produced a report titled "The nature and extent of Federal Government subsidies to the mining industry" dated April 2012 and authored by Matt Grundoff. The report stated that the Federal Government alone provides $4 billion annually to the mining industry in subsidies and concessions; this does not include the cost of providing the mining industry with infrastructure, nor State Government susidies.
  3. Environment Victoria listed "The Big 4: Australia's most expensive, wasteful and polluting fossil fuel subsidies. These were:
    1. The Energy Security Fund, $1billion annually;
    2. The Fuel Tax Credits program, around $6 billion annually;
    3. Accelerated depreciation for oil, gas and coal seam gas projects, estimated $3.14 billion over next 4 years;
    4. Aviation fuel tax concessions, $3.8 billion over 4 years.
The obtaining of the fossil fuels (coal mines, oil wells) come with big environmental problems – including the burning of a lot of fossil fuel, the release of CO2 from that, contamination due to mining waste, destruction of agricultural land, etc. Burning fossil fuels, particularly coal, bunkering oil and diesel, produces atmospheric contamination that is harmful to health.

Natural gas is often claimed to be considerably cleaner than coal, but natural gas is mostly methane, a very strong greenhouse gas. Recent research has indicated that leakage of methane into the atmosphere from gas wells and particularly from coal-seam-gas operations, might do more climate-changing harm even than coal.

The fossil fuel power stations dump their wastes into the atmosphere at no cost to their operators, but huge cost to the environment. These wastes cause climate change and many deaths and serious illnesses due to particulate matter, sulfur dioxide and oxides of nitrogen. See Wind turbines save lives and No level playing field.

Sustainable forms of power (including wind) require more work and more infrastructure for the same amount of power generation compared to fossil fuel power stations – thus have higher initial costs – but do not have the environmental problems associated with fossil fuel power.

If Australian governments were to cut out direct and indirect subsidies to the mining industry, and the fossil fuel power generators had to either stop dumping carbon dioxide into the atmosphere or pay for cleaning up the environmental damage that this causes, the fossil fuel industry could not compete economically with wind power.

While wind farmers get a premium for the power they generate, they generally do not get government money to build the wind farms.



Wind turbines at North Brown Hill Wind Farm
Turbines and mist
The foreground turbine was operating in the light breeze, the more distant ones were on the wrong side of the range. It was early on a misty morning.


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Do wind farms get government money?

The short answer is no. The electricity generated by wind farms comes with renewable energy certificates (RECs) and electricity retailers have to buy a number of RECs related to the total amount of electricity they sell; in effect, due to the Renewable Energy Target electricity retailers have to buy a certain amount of renewable electricity. This adds about 1¢ to the 25¢ per kWh that we pay for our electricity. (Also see Subsidies.)

 

Government support for tower manufacture

An indirect for of government subsidy, more to support a local industry than to support wind power, was a $2m grant from the South Australian Government to a Whyalla business that had a contract to build turbine towers for the Snowtown 2 Wind Farm. Reported 2013/08/07.
Wind farm opponents sometimes make the claim that wind farms receive large parts of their funding from government. While it is true that, because of the lack of a level playing field, wind farms cannot compete with fossil-fuelled power stations in terms of dollars per MWh of the electricity generated, I believe that very little government money goes into building wind farms.

The only exceptions I know of are one or two very small community owned wind farms that might have had significant government funding.

In general, wind farms are built with private money. However, they cannot compete with fossil-fuelled power stations so long as the latter are allowed to dump their wastes into the atmosphere without charge. These wastes cause climate change and many deaths and serious illnesses due to particulate matter, sulfur dioxide and oxides of nitrogen (see Wind turbines save lives. The electricity from renewable energy power stations is generally more expensive than from fossil-fuelled power stations, so electricity retailers have to have incentives to buy renewable energy.

Financial support for wind power in Australia

 
Comparison of average absolute support levels (market exchange rates, British pounds per megawatt-hour)
Wind power sup
Graph Credit, Frontier Economics
The graph on the right, from Frontier Economics, shows that Australia has a very low level of financial support for wind power compared to almost all OECD countries.

The report, which was prepared for the Department of Energy and Climate Change in the United Kingdom, can be downloaded from the UK Government site.

I do not know how the figures for the graph were calculated, but probably most of the 'support' for wind power in Australia would be from the Renewable Energy Certificates connected with the wind-generated electricity. Refer to the source report for more information.

I have recorded some estimated electricity costs by energy source on my Sustainable Energy page and the costs of wind power in particular are discussed on my wind power page.



 
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Timing of wind power generation
Do wind turbines generate power when it is most needed?
Can wind power provide base-load or peak-load?

 
Edited 2013/07/14

Peak load

Peak power consumption (peak load or peak demand) in hot climates often coincides with calmer than usual weather; so, on average, wind turbines generate less power at times of peak demand than at other times. Extreme peak loads usually comes on very hot days at about 5 or 6pm as people are coming home from work, turning on air conditioning and cooking dinner.

Base load

Coal-fired and nuclear power stations supply what is commonly called base load power; they can provide electricity constantly – subject to breakdowns and maintenance needs – but are not well suited to matching generation to the varying rate of consumption. No power grid could run on wind power alone – because the wind doesn't necessarily blow when it is needed – just as no power grid could run on coal-fired or nuclear power alone – because they are inflexible.

How does this relate to wind power?

 

Shadow Minister for Energy in SA talking-down sustainable energy

In September and October 2011 Mitch Williams was using the inability of solar and wind power to provide peak load power as a way of devaluing sustainable energy, both in writing and on ABC radio. See also Liberal party opposed to climate change action.
 

80-85% of SA's power by wind

I have received an unconfirmed report that in September 2011 the proportion of wind power in South Australia's electricity momentarily reached 80-85% and 1000 MW (total installed capacity is about 1200 MW).
Wind power is usually being generated in relatively low amounts at peak load, but there are notable exceptions; Renew Ecomony has published graphs that illustrate data showing the Bungendore Wind Farm is usually generating at high capacity at times of high electricity demand.

The fact that wind power is not available on demand makes wind-generated electricity less valuable than electricity that can be generated on demand. However, the importance of these points can be exaggerated, and is often exaggerated, by those who oppose sustainable energy (the box on the right contains one example).

The fact that around 26% of South Australia's power was produced by wind farms in 2011, and greenhouse emissions from power generation in SA declined by about 20% from 2005 to 2010, with no reduction in power reliability, proves that renewable energy can provide a substantial part of Australia's electricity needs and produce a positive contribution to the climate change crisis.

Gas-fired generators are relatively cheap to build, although expensive to run and damaging to the environment because of their greenhouse gas production. It is the gas-fired power stations that commonlyy 'fill in the gaps' between power generation and demand in Australia.

A more environmentally friendly way of generating power at peak load is pumped hydro. Alternatively demand-side management of the electrical supply system could be implemented, where some of the loads are controlled to suit the level of supply.

One of the advantages of solar power in Australia is that its maximum output occurs on the sunniest days, which are often also when the higher power demands come; although by 5 or 6pm, at peak load, their power generation is very much in decline.



Are wind turbines a fire hazard?

A dubious claim on the frequency of wind turbine fires

This section has been (2014/07/23) replaced by a dedicated page on wind turbines and fires.


Television reception and wind turbines

Wind turbines can adversely affect television reception nearby. Typically the company building the wind farm will measure the TV signal quality at all the houses likely to be affected before and after construction. Where there is a significant deterioration in the signal following construction the company will provide some alternative, such as satellite TV.


 
Updated 2013/08/14

Radar interference

Weather radar

The moving blades of the wind turbines cause some problems to the operators of weather radars. The radar installations can be programed to ignore the returning signals from the wind farms. Large stationary installations also cause radar reflections, but these are more easily compensated for.

Surveillance radar

The following was provided by Pager Power Ltd.

Surveillance radar, used to detect aircraft and display their position on radar screens, can also show returns from other moving sources such as cars, trains and blades of a wind turbine. Wind turbine radar effects are dependent upon factors such as the type of radar installation; the distance to the turbines and the extent to which the turbines are visible to the radar. A common effect seen on Primary Surveillance Radar screens is that the rotor blades can produce intermittent radar returns. For this reason radar operators can object to turbine developments.

Technical effects include desensitization, receiver saturation and false returns. The most significant of these, for an air traffic control radar, is false returns. On older analogue type radar wind turbines can appear as clutter. There are many sources of clutter including insects, weather, traffic and birds.



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Updated 2012/04/29

Is solar power somehow 'better' than wind power?

Some people seem to believe that solar power is somehow better or more environmentally friendly than wind power. (The pros and cons of all the common methods of generating electricity have been dealt with elswhere; of course both wind and solar are much more environmentally-friendly than are coal, oil, gas and nuclear.)

 

Wind and solar power can complement each other

In hot weather winds tend to be lighter so wind turbines generate less electricity, at the same time the sun is likely to be shining and high in the sky, and solar power generation would be high. When the sun is not shining the wind is more likely to be blowing.
How should we judge which is 'better'? Logically we need to look at the cost, in both financial and environmental terms, of each in relation to the amount of electricity generated; and we should look at how wind and solar fit the electricity demand cycle.

In 2009 wind must be more profitable than solar. If it were not so then surely we would be seeing solar power stations all over the place instead of wind farms? There is no government bias toward wind power and away from solar that I know of. The people who invest their money in wind farms and the business people running the companies that build wind farms are not stupid.

By the way, a typical utility scale wind turbine has an installed capacity of 2MW and a capacity factor of 34% while the average Australian roof-top solar installation is 2kW and solar PV has a capacity factor of about 16%; so a typical wind turbine will generate as much electricity as 2000 average roof-top solar systems and a wind farm of 50 such turbines will generate as much power as 100 000 roof-top solar systems.

A comparison of wind and solar

Operational factors
FactorWindSolar
Generation at peak load Peak load (or peak demand) in Australia usually coincides with exceptionally hot weather and tends to come at around 6pm as people are arriving home from work, switching on air conditioners and preparing dinner.
Wind power generation is lower than average during periods of peak demand because exceptionally hot days tend not to be windy, see Wind Power in SA.
Solar power facilities will be generating at a high rate through the day on hot days, because it is most likely that the sky will be clear, but with the lower sun around 6pm their generation will have greatly declined. Solar PV panel productivity increases greatly with higher light levels, but decreases slightly with higher temperatures. (For more detail on this see elsewhere.)
Capacity factor The average capacity factor for wind power in Australia is about 34%. That is, a wind farm of 30 MW will generate about a third of its rated capacity, 10 MW, on average. The average capacity factor for solar photovoltaic systems is around 16% to 18%. That is, a solar power installation of 10 kW will generate about 1.7 kW, or about a sixth of its rated capacity, on average.
 
Cost
 WindSolar
Two proposed projects near Geraldton, WA Mumbida Wind Farm in WA is expected to cost $150m and will have an installed capacity of 55 MW. Assuming a capacity factor of 34% (typical for SE Australian wind farms) it will generate 164 GWh per year. Neglecting maintenance costs and assuming a 25 year life, this works out at a cost of about 3.7 cents per kWh of power generated. Greenough River Solar Plant, also in WA, is expected to cost $50m and will have an installed capacity of 10MW. Assuming a capacity factor of 18% (reasonable for a solar PV installations in this latitude) it will generate 14 GWh per year. Again, neglecting maintenance costs and assuming a 25 year life, this works out at a cost of about 14 cents per kWh of power generated.
Based on http://www.abc.net.au/news/2011-08-25/renewable-energy-supplement/2855838
 WindSolar
Two actual projects in SA - assuming 7.5% annual cost of capital Hallett #1 Wind Farm cost $233 million, so the annual cost of capital is $17.46 million. With annual maintenance costs of $6.75 million (from AGL), total annual costs come to $24.21 million. Annual generation is 326 000 MWh, so the cost of the power generated can be calculated as $74.26/MWh, or 7.4 cents per kWh. The total cost of my roof-top solar system in the Clare area was $8900, so the annual cost of capital is $668. Assuming no maintenance costs, this is also the total annual cost. Annual generation is 2096 kWh, so the cost of the power generated can be calculated as 32 cents per kWh – about four times that of Hallett #1.
 
Environmental factors
FactorWindSolar
Land covered Wind turbines occupy very little land, the necessary roads and 'hard-stands' for building and accessing the turbines cover more, but still not large areas for the amount of electricity generated. A typical modern, utility scale, turbine (rated at 2.1 MW) can generate about 6.4 GWh per year. Solar power is very diffuse. A solar power station must cover a large area if it is to produce a lot of power. This is way outside of my limited expertise, but it seems that the best areas in the world for solar power receive around nearly 3 MWh per year per square metre (for panels aligned to the optimal [fixed] angle for the latitude involved). Assuming an efficiency of 15% (typical of modern crystalline silicon cells), a collection area of 13 000 m2 (say 100 m by 130 m) would be needed to generate the same amount of energy as the 2.1 MW wind turbine discussed in the box on the left.
Site
damage
Wind turbines generate the maximum electricity if they are placed on the tops of ridges; rounded, bare ridges being better for wind flow than rocky or tree-covered ridges. Building roads and erecting turbines on ridge-lines carries with it some risk of causing erosion. Solar power stations can be built anywhere there is a lot of sunshine. Flat areas are cheaper to build on than hills. The solar collectors can be placed where the existing vegetation has little conservation value. However, as mentioned above, they must cover large areas.
Visual On-shore wind turbines are often on ridges and therefore are conspicuous from long distances. Off-shore wind turbines are expensive, and the further off-shore the more expensive they are.
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Solar power stations can be sited inconspicuously.
 
Environmental factors continued
FactorWindSolar
Embodied costs There are environmental costs in mining and smelting the steel from which wind turbine towers are made. Petrochemicals are used to produce the glass-reinforced polymers used for turbine blades: petrochemical industries are notorious for being polluting. Rare-earth elements are used in the magnets in wind turbines; rare-earth mining can be polluting when in third-world countries. Large quantities of steel are also needed for the support structures for solar collectors. Silicon solar panel production is not without environmental costs. Some advanced solar cells use gallium arsenide; gallium is quite a rare element and arsenic is highly toxic – the ultimate disposal of panels composed of such materials would need to be done responsibly.
Embodied energy Energy must be expended to build the wind farm and the wind turbines before any energy is generated by the wind farm. I have discussed this question elsewhere on this page. A wind farm will 'pay-back' the energy required to build it in the first few months of operation. So far as I have been able to find out it takes from two to four years to pay back the energy involved in manufacturing photovoltaic panels, see The Pros and Cons of Various Methods of Generating Electricity.
Water consumption Wind farms require very little water. Solar power stations using photovoltaic panels without concentration of sun-light require little water; those that concentrate sun-light and solar-thermal power stations require substantial volumes of water for cooling.

The table above shows that deciding whether solar or wind is the least environmentally damaging is not easy. Also see How does wind power compare to roof-top solar?.



Leakage of oil

Leaking lubricating oil or hydraulic fluid from wind turbines may be a problem. Fluids running down turbine blades may be scattered over the surrounding area, in some cases causing contamination of drinking water.

Of course the potential of this would be similar to any other machinery in operation, for example, farm tractors and earth moving equipment.



Erosion of sites

A complaint heard from a Hallett resident was that the building of roads and hardstands in the hills of the area was going to lead to terrible erosion problems in the future. I should record here that I have visited many wind farms and, while I have seen minor erosion adjacent to some roads (as I have seen on the sides of many private and public roads), I am yet to see out-of-control erosion caused by wind farm construction.

Brendan Ryan of Suzlon gave me the following:

"The access roads are built to a high standard, I always joke that you can tell them apart from the local roads as they are in better condition. The drainage plan for the site is well thought out and the road compaction is quite high as well as the forming of the shoulders. Built Environs have to do maintenance work several years after the road is built to tease out any areas that may be an issue such as where ponding occurs. I think if you look at Hallett Stage One after several rain events you will find the roads holding up okay."

I inquired with Built Environs (who have constructed roads and hard-stands on several SA wind farms), but got no reply.



Bird deaths from wind turbines
Power lines and turbines
Wind turbines do kill some birds, but the laticed pylons and wires in this photo are a greater danger to birds than the turbines. The transmission line was built to take coal-generated power from Port Augusta to Adelaide.
North Brown Hill Wind Farm


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Bird deaths from wind turbines

 
Updated 2013/11/28
One of the most commonly heard complaints against wind turbines is that the fast moving turbine blades kill birds. It is true that some birds are killed by wind turbines, but the numbers of bird deaths are far less than from collisions with steel-lattice towers, power lines, house windows and cars, and far more birds are taken by feral cats. Unfortunately large raptors (hawks and eagles) are often among those few birds that are killed by turbine blades.

 

Save birds, build more wind turbines

Mike Barnard tells how to save 70 million birds a year by building more wind farms. He calculated that fossil fuel electricity generation kills 17 times more birds per gigawatt-hour than wind energy.

New Scientist journal

Up to half of all birds are threatened by climate change; New Scientist. Changing from burning fossil fuels to renewable energy will slow climate change and give birds more time to adapt.

Selective "conservationists"

Right wing media ignored the death of 7500 songbirds killed over a liquified natural gas plant, while giving coverage to a very few bird deaths at wind farms.

Two feral cats

I won't go into detail, but data on bird deaths at one of Australia's biggest wind farms, Waubra (see below), and a Government study on Macquarie Island suggests that two feral cats would kill more birds than all the turbines at Waubra.
In an effort to show, by example, that wind turbines do much more good than harm for birds – by reducing greenhouse gas production and therefore slowing climate change – the UK Royal Society for the Protection of Birds (RSPB) plans to build a big wind turbine at its headquarters.



The USA National Wildlife Federation has a page on 'Encouraging Renewable Energy'. They write "NWF works to remove the barriers so that America and the rest of the world will quickly expand wind, solar, geothermal and biomass energy to power a new clean energy economy for all Americans."

Research

A study, published in PLOS ONE and funded by the American Wind Wildlife Institute, was based on data from 116 studies conducted in the USA and Canada. As reported in Ecocide Alert the study found that "wind turbines kill far fewer birds in North America than do cats or collisions with cell towers. The study concentrated on small passerine birds. View the original report at PLOS ONE.

The Canadian journal, Avian Conservation & Ecology, published a research paper titled 'Canadian Estimate of Bird Mortality Due to Collisions and Direct Habitat Loss Associated with Wind Turbine Developments' in 2013. The authors used data from carcass searches from 43 wind farms and concluded that on average about 8 birds were killed per turbine per year.

Benjamin Sovocool, for the peer-reviewed Journal of Integrative Environmental Sciences (vol. 9, No. 4) wrote a paper titled The Avian and Wildlife Costs of Fossil Fuels and Nuclear Power in which he compared bird deaths from these sources of electricity to wind power. His paper was a synthesis of findings from many studies and was dated 2012/06/30. He provided figures of 0.27 avian fatalities from wind power per gigawatt-hour of electricity generated, 0.6/GWh for nuclear power and 9.4/GWh for fossil-fueled power stations.

"Estimates of bird mortality at wind facilities in the contiguous United States" by Scott R. Loss, Tom Will and Peter P. Marra; published in Biological Conservation, Vol. 168, Dec. 2013, Pages 201-209.

This synthesis study conclued that between 140 000 and 328 000 birds are killed annually by wind turbines in the USA. Loss et. al. list bird deaths "per MW", presumably meaning per installed MW. I have converted this to bird deaths per generated GWh, based on a 30% capacity factor. Loss's figure of 5.76 deaths/MW for the contiguouls USA becomes 2.19/GWh; about ten times as high as Sovocool's estimate (see above).



The UK Centre for Sustainable Energy published a document Common concerns about wind power in which it was stated that "wind turbines are responsible for less than 0.01% of avian mortality caused by humans, with by far the largest cause of deaths being standing buildings (more precisely, the windows), power lines and domestic cats". In the long term every wind turbine saves bird's lives by slowing the climate change that will be a far greater bird killer.

The recorded rate of bird mortality associated with the three Australian wind farms that I have seen figures for is between 0.23 and 2.7 birds per turbine per year. Several of the world's bird protection organisations hold that climate change is a far greater threat to birds than are turbines.

 
Bird mortality
Graph from the UK Centre for Sustainable Energy, data from A Summary and Comparison of Bird Mortality from Anthropogenic Causes with an Emphasis on Collisions; Wallace P. Erickson, Gregory D. Johnson and David P. Young Jr.



A study of avian mortality by Environment Canada gives the following figures for annual bird deaths:
SourceNumber of deaths
Cats, feral116 000 000
Cate, domestic80 000 000
Power transmission line collisions26 000 000
Buildings – Houses22 000 000
Vehicle collisions14 000 000
Agricultural pesticides2 700 000
Harvest – Nonmigratory birds2 400 000
... another 11 catagories...
then: Wind energy17 000
The above figures were taken from Table 1 on page 18 of the document.
Reference: "A Synthesis of Human-related Avian Mortality in Canada" by Anna M. Calvert, Christine A. Bishop, Richard D. Elliot, Elizabeth A. Krebs, Tyler M. Kydd, Craig S. Machtans and Gregory J. Robertson; Environment Canada, 2013.

Quoting from a fact sheet published by the Australian Greenhouse Office and AusWEA (Australian Wind Energy Association)...
"A US study published in 2001 carried out by Western Ecosystems Technology puts wind turbine collision into perspective with bird collisions with other structures: [deaths per year?]
  • Vehicles: 60 million to 80 million bird deaths
  • Buildings and windows: 98 million to 980 million
  • Power lines: tens of thousands to 174 million
  • Communication towers: 4 million to 50 million
  • Wind generation facilities: 10 000 to 40 000
The study estimates that wind farms kill an average of 2.9 birds per turbine per year in the US – equivalent to less than 0.02% of the staggering 200-500 million collision related [bird] deaths in that country"
It should be noted that wind farm bird deaths per gigawatt generated are likely to be more numerous in the US than in Australia because:
  • There are many more small turbines in the US than in Australia;
  • Many older US turbines have steel lattice towers, similar to those of communication towers, while all industrial scale Australian turbines have solid steel tube towers;
  • Being smaller, US turbine blades are closer to the ground; common birds rarely fly as high as the blades of Australian turbines;


At the Codrington wind farm in Victoria (14 turbines of 1.3 MW each) 20 bird and bat deaths were detected between 2001 and 2003.

 
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Wikipedia states that...
"studies show that the number of birds killed by wind turbines is negligible compared to the number that die as a result of other human activities such as traffic, hunting, power lines and high-rise buildings and especially the environmental impacts of using non-clean power sources. For example, in the UK, where there are several hundred turbines, about one bird is killed per turbine per year; 10 million per year are killed by cars alone."

Wikipedia also discusses bird impact in its article on the Environmental effects of wind power.



Mike Barnard has an enlightening piece on Quora about birds and wind farms. Mike writes that:
"Replacing all fossil fuel generation with wind turbines world wide would save roughly 14 million birds lives annually. Declawing all house cats would save up to 500 million birds lives annually. Turning off lights in all windows at night would save up to 950 million birds live annually."
He goes into far more details in his piece, and he gives the references to back-up his statements.

Audubon has a Net page on its position on wind power. Basically, Audubon recognise that wind turbines do pose threats to birds, but that Climate Change is a much greater threat and sustainable energy, including well sited wind farms, are needed if the world is to limit the damage done to birds by Climate Change.

 
This section updated 2012/07/25

Bird deaths at Waubra


 

Bird deaths in two years at Waubra

From Acciona's newsleter #18...
TotalsNumber of
collisions
Australian Magpie23
Brown Falcon10
Nankeen Kestrel8
Crow6
Wedge Tailed Eagle4
Little Eagle2
Australian Shelduck1
Grey Teal1
Hoary-headed Grebe1
Little Button Quail1
Raven1
Straw-necked ibis1
Swamp Harrier1
Welcome Swallow1
Total61
David Clarke of Acciona is on record as stating the following:
"Acciona implements a comprehensive bird monitoring program at the Waubra Wind Farm in accordance with Avifauna Management Plan which was approved by the Minister for Planning in October 2006. This Plan was supported by extensive bird surveys of the site prior to commissioning of the wind farm.

The first year of bird mortality searches at the Waubra Wind Farm were completed in 2010. Dead bird searches are done by two highly trained German Short-haired Pointers and their handler. It is a unique survey method that allows a search of large areas of the wind farm to be done in an efficient and cost-effective manner. The dogs have also proven to have a higher searcher efficiency than people.

There were 28 birds found during the first year of mortality searches. No nationally or state threatened species were impacted. Magpies accounted for 43% of all bird collisions. The extrapolated results for the entire wind farm indicate that 1.65 birds are killed per turbine annually. This can also be presented as 1.1 birds/MW/year.

The mortality rates when compared to wind farms overseas suggest that impacts at Waubra are relatively low. An investigation of 19 wind energy facilities in the USA showed an average rate of 3 birds/MW/year."

Novel Scavenger Removal Trial

In order to test how many carcasses of birds killed by turbines are removed by scavengers researchers place bird carcasses and see how long it takes for scavengers to remove them. A paper by Smallwood, Bell, Snyder and Didonata (Journal of Wildlife Management 74(5):1089-1097; 2010; DOI: 10.2193/2009-266) (no longer available on the Net?) suggests that in conventional trials researchers might have dumped too many carcasses in small areas to get accurate results.
 
Updated 2013/04/26

Doctor Cindy Hull answers some questions on birds and wind turbines

 

Two of Dr Hull's reports

New Zealand Journal of Zoology; Avian collisions at two wind farms in Tasmania, Australia: taxanomic and ecological characteristics of colliders versus non-colliders. C L Hull, E M Stark, S Peruzzo, C C Sims. Accepted for publication 2012/12/07.

Wiley online Library; published in the Wildlife Society Bulletin; 2013/03/19; Behavior and turbine avoidance rates of eagles at two wind farms in Tasmania, Australia; Cindy L. Hull1, Stuart C. Muir.

Update from Dr Hull

Dr Hull mentioned on 2013/11/05 that there had been no eagle collisions at Studland Bay or Bluff Point wind farms (formerly Woolnorth Wind Farm) for three years.

Note on species affected from Dr Hull

Dr Hull mentioned this on 2013/12/02.
"... we have found at our sites that only 20% of the species of birds present at our wind farms were found to collide with turbines, and there are specific characteristics of those species that collided. The most important being that the bird has to be one that spends some time in the rotor swept area, and there are many birds that dont spend time at this height. So just being on site doesn't mean that a species is at risk of collision (and this is therefore a different impact to something ubiquitous like climate change). Our paper is in New Zealand Journal of Zoology 40:1, 47-62."
 
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Dr Hull has been involved in studying birds and their interaction with wind turbines at the Bluff Point and Studland Bay wind farms in north-western Tasmania since 2002, before the wind farms were built. She was kind enough to answer some questions that I put to her about her studies.
Question What has been learned?
Answer Not all species are equally at risk of collision with turbines. Of the species of bird occurring at our two wind farms, only about 20% are involved in collisions with turbines. This means that just being on site does not mean you are at risk of colliding with turbines. There are specific factors associated with collision risk – which we are starting to document. The same applies to raptors, not all raptors on a site are at risk of collision with turbines.

Some species of eagle have collided with turbines, but not goshawks and, other than brown falcons, not other species of falcon. A second key finding is that eagles actively avoid turbines most of the time. It is currently unknown why they sometimes do not. This is a lot of work being done in the UK at present about vision in birds and how this might impact on their ability to detect turbines. This research has lots of potential for informing strategies to make turbines more visible to birds (who see quite differently to humans).

Eagles continue to breed at our sites. Provided an adult is not killed, their breeding success rate appears to be better than outside the wind farm and there are likely reasons for this. The eagle nests on site are in the middle of protected remnant vegetation with at least 500m buffers to turbines. No person (other than those doing the breeding surveys), vehicle or any other activities are allowed in these areas so the nests are left undisturbed.

Question How many raptors are killed?
Answer At our sites, we have 1-2 eagles collide per year. We have also had 6 brown falcons at these wind farms (6 total over the 10 years of operation) and 2 swamp harriers. No other species of raptor, although there are nine species on these sites. People often make reference to the Altamont Pass Wind Resource Area in California. This wind farm has had numerous raptor collisions (particular species), but is recognised as being an old fashioned style wind farm and new wind farms are not comparable with these raptor collision rates (see Smallwoods work).

Question What studies are being done?
Answer Many. There are the detailed monitoring programs to detect the birds (and bats) that collide with the turbines, there are also breeding success surveys to determine if the wind farms are affecting breeding, genetic studies looking at the relatedness between individuals that collide and those on sites, detailed investigations into how eagles use the wind farms and a range of trials of mitigation strategies to reduce collision risk. These are reported in the Annual environment reports.

Question How can collisions be minimised?
Answer The short answer is we don't have an answer yet, but many people are actively and intensively studying the issue around the world, including us. The best approach we can take is to understand the factors involved in collision risk and then use this information to develop mitigation strategies. There are lots of theories around trying to explain collision risk, so what we as scientists need to do is test these theories and see if there is support for them. It benefits no one to just assume the theories are correct. Mitigation can only be built around understanding the factors involved in why birds collide and directly tackling these.

Question Do you know of any estimates on the numbers of wedge tailed eagles in Tas?
Answer The estimates are vague, but population variability modelling used the best estimates that the population was 1000-1500 (about half are floaters).
The Tasmanian sub-species of the Australian wedge tailed eagle is endangered and its population is declining. Doctor Hull also said that there had been no known wedge tailed eagle deaths at either of the wind farms in 2011 and the first half of 2012 (that is, up to the time of the comunication).

Doctor Hull has some interesting graphics illustrating her studies, but as these are in papers that she has submitted for publication in peer-reviewed journals she was not able to release them at the present.



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Fragmentation of bird habitat

I have received correspondence from Chia-Yang (John) Tsai of the Changhua Coast Conservation Action, Taiwan. He stated that his studies indicate that while bird collision has not been a significant problem, the fragmentation of bird habitat by wind farms can be.
 
Birds and turbine
Acknowledgement, John Tsai; his Flickr link.

I have taken the liberty of slightly modifying the text that I received in an attempt to make Tsai's meaning clearer (his English is limited).

"We found that a very direct effect of wind turbines on birds is the disruption of flying path between feeding and roosting sites. That is, the wind turbines cause a habitat fragmentation or a barrier effect. This is sometimes crucial for birds in their energy balance. If they spend too much time avoiding wind turbines or finding a safe way to their roosting sites, they are at higher risk of loosing their optimal habitat use pattern (the shortest route or minimization of energy expenditure).

We have done some research on the interactions between birds and wind turbines, showing that the collision risk might be low, but habitat fragmentation effect significantly high. So, wind turbines should be positioned with regard to bird flight paths.

Bird collision on wind turbines have been reported in many journals and papers; we have not yet found any birds hit. We recently started our research into the construction and operation of wind power and we intend to continue for several years.

I hope the research paper we are writing can be published soon so that more people and decision makers will have better information on which to base wind farm and turbine locating decisions.

Best regards,
Chia-Yang Tsai"



Pygmy bluetongue lizards

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The pygmy bluetongue, Tiliqua adelaidensis, is classed as an endangered species and occurs in grasslands of Mid-North South Australia; the same region as the Hallett wind farms. A few populations occur in the Port Wakefield to Balaklava area.

The lizards live in spider burrows after either evicting or eating the spiders. Information on the species is available from several pages at Environment SA who state that there are 22 known sites with an estimated population of several hundred lizards living in each of at least ten of these sites.

Soil disturbance in lizard habitat destroys lizard burrows and kills lizards. It seems that they do not live much in stony hill-top areas, perhaps because there are few spider burrows in such hard and stony ground. The lizards cannot live in recently ploughed land, and are very slow to re-occupy ploughed land.

ABC Rural carried an article headlined "Introduction of wind farms helps find endangered lizards". A part is quoted:

Senior herpetology researcher at the [South Australian] Museum, Doctor Mark Hutchinson, says greater environmental scrutiny for wind farm developments has had an unexpected side-effect. "In the periphery of it where people are looking to put in tracks or other things, down the bottoms of hills and on the edges of where the windfarms are going, the lizards have turned up.


Loss of native vegetation

In Australia wind farms are usually built on the tops of ridges; bare, rounded ridges are preferred by the wind farmers because the air-flow is less turbulent.

On the whole wind farms will provide more protection to bushland and grassland than cause damage. Climate change is a far greater threat to Australia's native vegetation than is the growth of the wind power industry. The June 2011 issue of Scientific American included a study about fire hazard linked to climate change. It seems that the area burned by wild fires in the US in the average year, given a one degree rise in temperatures, is expected to be up to six times as large as at present, depending on the ecoregion. And bushfires are not the only hazard to native vegetation that comes with climate change.

So we must replace the fossil-fuel fired power stations with renewable energy. Wind power is the most economically viable form of renewable energy at present (2012). Solar has great potential and is fast becoming cost-competative to wind, but is not there yet. The potential for hydro power in Australia is quite small, and if we dam rivers to get more hydro that will be much more damaging to the environment than will wind power developments.

 
Crane and towers
Waterloo Wind Farm, South Australia.
Native trees had to be removed for the building of this wind farm. Roaring 40s have an off-set arrangement with the Native Vegetation Council in which $800 000 will be paid toward revegetation and conservation programs.
There is little remnant native vegetation on many wind farm sites; for example I have photos of:

In South Australia...

In Victoria...

There is more native vegetation at:


 
Turbines scattered through remnant vegitation
Scrub and turbines
Turbines can be scattered through scrub, using existing clearings as far as possible
In most cases wind farm sites have a long history of grazing, and this has degraded the vegetation. Standard procedure in Australia seems to be that the wind farmers will finance revegetation elsewhere to try to compensate for the lost vegetation.

The proposed Mt Bryan Wind Farm is an interesting case, where damage to native vegetation has been claimed by opponents, but where very little will take place so far as I can tell.

Of course remnant native vegetion is valuable and should be retained wherever possible.



General environmental concerns

Specific environmental concerns such as bird and bat deaths, fragmentation of bird habitat, visual objections, erosion and effects on tourism and land values are dealt with elsewhere on this page.

Roads must be built to gain access to wind turbine sites and 'hard-stands' flattened out where the turbines are to stand; there are environmental problems associated with road building, with the roads themselves and the hard-stands. Roads and road damage outside the area of actual wind farm construction is discussed elsewhere on this page.

  • In some areas native vegetation is destroyed;
  • Sites of significance to Aborigines can be damaged;
  • The existence of a road is a barrier to the natural movement of some native animals;
  • Poorly planned or constructed roads in the hilly areas preferred for wind farms can increase erosion potential.
The damage associated with road building can be minimised if due consideration to potential environmental damage is given in both the planning and construction stages.

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The question of whether a wind farm can change the local climate is dealt with elsewhere on this page, and I have discussed whether very extensive development of wind power Australia-wide might affect weather on the Wind power potential page.



Roads and road damage

 
Road damage
Image credit Warrnambool Standard and Damian White
See text for relevance
Environmental problems caused by the building of new roads on wind farm sites is discussed under General environmental concerns.

Dust can be a problem during wind farm construction due to increased traffic movements. The increased traffic itself can also be a problem.

Wind farm opponents commonly complain that the heavy traffic needed to bring in wind farm components damages local roads. Like so many statements from wind farm opponents this is a half-truth. Yes, the additional heavy traffic does damage some of the roads, but I believe that there is also usually an arrangement between the wind farmer and council or between wind farmer and government whereby the wind farmer has to cover the cost of the necessary road repair.

The image on the right was printed in the Warrnambool Standard with the caption "A driver tries to traverse the crumbling Macarthur-Penshurst Road". In fact it is obvious that the driver is intentionally driving on the road shoulder for the purpose of obtaining a picture with impact. It also appears that the road is not "crumbling" in this section, the sealed part seems to be in good condition, it is only the earth shoulder that is rutted.

The road shoulder has probably been damaged by heavy wind farm traffic and it would be necessary for vehicles to move onto the shoulder when passing oncoming traffic, but it is a pity that so much of the media gives a higher priority to impact and sensationalism than truth.



Do environmentalists oppose wind farms?

Some of those who oppose wind farms claim to be environmentalists, some are perceived by others as environmentalists (see Motivations).

In fact environmental organisations are strongly in favour of wind power. For example:

  • Friends of the Earth, Victoria, have recently (early 2011) started a campaign called 'Yes 2 Renewables' in support of wind power;
  • WWF (previously World Wildlife Fund) see wind power as a big part of their 100% renewables by 2050 campaign (The Energy Report, 100% renewable energy by 2050, released in early 2011);
  • Environment Victoria "is a strong supporter of wind technlology" (from their submission to the Senate inquiry into "The Social and Economical Impact of Rural Windfarms", Australia, 2011);
  • "ACF [Australian Conservation Foundation] is generally supportive of wind power (and other forms of clean, renewable energy)" (pers. com.);
  • Gippsland Friends of Future Generations are strongly in favour of wind power.
 
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The opposition is not coming from serious environmentalists who look at the big picture. Much of it is coming from NIMBY (not in my back yard) people; people who simply don't like the look of turbines, and those who are envious of nearby farmers getting big lease payments while they see themselves as getting nothing. Several groups of people have banded together to oppose wind power, but they could not be called environmental groups because their primary, and probably sole, function is the opposition of local wind power development. See Waubra Foundation for example.


 
Updated 2012/07/12

Do turbines frighten animals?

 
Young cattle grazing peacefully beneath wind turbines
cattle and turbine
Toora Wind Farm
The argument that wind turbines frighten sheep, cattle, horses or other livestock is one that is used by wind farm opponents periodically. I think these photographs shows that, if ever turbines do frighten stock, the stock become accustomed to the turbines and behave quite normally in their near vicinity. (I have also seen kangaroos grazing quietly near turbines.)

Whether there is a period during which animals get used to the turbines I don't know.

Having been a dairy farmer for eight years, and having had sheep grazing on my property at Clare for the last 15 years, my own feeling is that neither cattle nor sheep would be much concerned by wind turbines.

 
Sheep sheltering in the shade of a working turbine
Sheep sheltering
Clements Gap Wind Farm
Low lambing rates at Waubra had been attributed to wind turbines (Aug. 2010). When the sheep owner called a vet, the vet said that low lambing rates had been a problem in much of the area recently, whether or not turbines were nearby.

I discussed this with a farmer who has a stud sheep business as well as turbines on his property near the Clements Gap Wind Farm; he told me that the sheep like the turbines, resting in their shade in summer, and that he had no problem with falling lambing rates since the turbines were built.

I have often seen sheep sheltering in the shade cast by wind turbine towers, as in the photo at the right.

Nichols Poultry have their own 225kW wind turbine, one of the biggest in Australia in private hands, on their free-range poultry farm in Tasmania. Nichols have a Net site on which they provide information about their operation. Would Nichols do this if wind turbines harmed animals?
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Edited 2013/10/21

The wind doesn't blow all the time
The need for backup

 

Wind energy and storage

The American Wind Energy Association has a very good page on wind energy and storage. It stated: "In the U.S., numerous peer-reviewed studies have concluded that wind energy can provide 20% or more of our electricity without any need for energy storage."

How much backup does a wind farm require?

Mike Barnard has written a page on this and how it compares to conventional generation. Mike's article was based on international studies of the electricity supply industry. The conclusion was that no special backup is required if the total installed wind power contribution is below 20%.

A very good article explaining back-up and wind power was written by Lyn Harrison in WindPower Monthly, 2013/08/01.

Dr David Osmond and Luke Osborne have written an informative paper on "Peaking Capacity, CO2-e Emissions and Pricing in the South Australian Electricity Grid with High Wind Penetration" that deals with this point.

South Australia has, on average, about 33% of its electricity generated by wind farms (as of mid 2014). So far as I know, no special backup generation has been installed specifically to handle the intermittency of the wind farm generation. (I live in SA.)

It is true that the wind doesn't blow all the time, when the wind isn't blowing wind turbines don't generate electricity and the short-fall has to be made up from some other source. This is probably the biggest disadvantage of wind power. But when the wind is blowing wind turbines are generating and are displacing fossil fuel generated power. It's all in how you look at it: glass half empty or glass half full.

It is very important to distinguish between variability and reliability. Wind turbine generation is variable depending on the wind, but wind turbines are typically around 97% to 99% reliable. The wind can be forecast with a fair degree of accuracy, so those who run the power grid know how much power to expect from wind farms.

It is also very important to understand that all forms of generation require backup. All power stations are closed down for periodic maintenance and are subject to sudden and unexpected breakdown. The power transmission grid is also subject to unexpected failure at times. The advent of wind power has made little difference to the way in which the power grid operates.

The fact that wind farms are wide spread in Australia smooths the combined generation. When the wind slows in one area it will still be blowing a hundred kilometres away.

Power generated from all AEMO monitored wind farms in Australia, 2012/01/15, combined output
All wind farms
Graphic credit: http://windfarmperformance.info
The Y-scale is megawatts (MW), the X-scale is time in 24-hour notation.

The graph above shows combined generation from most of the wind farms in eastern Australia on 2012/01/15. Note that the output varies only slowly and gradually – the slope of the line is gentle. Having a gradually varying output like this, combined with the fact that wind speed is predictable to a fair degree, makes it easy for the grid operator to bring other generators on-line as required. (2012/01/15 was the most recent full day of data available when this section was added; it was a pretty typical day.)

Power generated from all AEMO monitored wind farms in Australia, 2012/01/15, shown individually
All wind farms
Graphic credit: http://windfarmperformance.info
The Y-scale is capacity factor, the X-scale is time in 24-hour notation.
Each coloured line records the output of one wind farm.

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The graph above shows generation from most of the wind farms in eastern Australia individually on 2012/01/15; the same day as the earlier graph. Note that the output of each is quite variable – the lines are more steeply sloping than the earlier graph – however, the output of wind farms varies over periods of many minutes and hours, not significantly over periods of seconds.

Even within one large wind farm though, variation is 'averaged-out' because as the wind slows in one part of the wind farm it might be blowing more strongly in another part. Compare this graph with the one of the small Wonthaggi Wind Farm, below.

 

The ideal generator of electricity

The perfect electricity generating method would cheaply produce a varying amount of power that would exactly match the varying demand with 100% reliability and while producing no pollution.

It doesn't exist. (See the pros and cons of various methods of generating electricity.) The inflexibility of coal-fired and nuclear power stations is almost as great a limitation as the pseudo-random variation of wind power generators. All power generators have scheduled interruptions for maintenance and unscheduled breakdowns.

Wind power generation graph for August 2007 from Wonthaggi, Victoria
Wind 
graph
Acknowledgement, Wind Power Pty. Ltd.
This is a very small wind farm, with only six turbines, so its output is particularly variable in the short term.
Power curve of a Suzlon S88, 2.1 MW turbine
Power curve
Data from Suzlon
This graph is explained in Wind speed range of turbines, below
The variability of the wind is the most obvious problem with wind-generated electricity; when the wind stops then a wind farm stops generating electricity. The intermittency and imperfect predictability of wind-generated power lowers its value. (On the other hand, what opponents of renewable energy often seem to forget is that all commercial power generators go off-line unpredictably sometimes. Generally the power system copes.)

Wind can now be forecast fairly reliably 24 to 48 hours ahead. When wind farms are not generating the electricity deficit can be taken up by other generators such as natural gas-fired power stations. Most of the backup generators only run when required to make up the short-fall in power generation and are idle at other times. Of course there are costs involved in keeping power stations on standby. Some backup also needs to be kept running as spinning reserve so that it can be brought on-line at very short notice, but this has always been so in case of break-down of generators.

In fact, since the variability of power generation from wind farms is slow and predictable it is easier to cope with in a power grid than the occasional breakdown of a large fossil-fuel or nuclear generator, which will be sudden, unpredictable, and produce a big deficit in the power supply-demand balance. If one turbine in a wind farm breaks-down the power output of the whole wind farm will only drop a little because the other turbines continue operating.

All power stations are off-line some of the time. Fossil-fuelled power stations are typically available around 85% of the time; at other times they are undergoing maintenance or suffering breakdown, etcetera. For example, on the evening of 2013/05/31 600MW of generating capacity from AGL's Torrens Island power station was lost and at the same time 200MW was lost from Origin Energy's Osborne plant, both in South Australia. (This is equivalent to the maximum power output from about 400 wind turbines.) The system coped with this loss. There has always been backup in the system, the advent of wind power has not produced any need for greater backup.

A part of the problem of the pseudo-random variability of supply and demand could be overcome by introducing Supply Dependent Load, which is discussed in my Sustainable Electricity page and hydropower could also be used to balance generation and consumption (as is done very effectively with wind power in Denmark balanced by hydropower from Norway).

If it was economically (or environmentally) justified, then additional power supply-and-demand balancing methods could be introduced. I have included a section on how pumped hydro power can be used to balance the generation of wind power on my Sustainable Energy page. Of course developing pumped hydro has its own cost, but power that can be generated on demand and at short notice receives high prices in a supply and demand based power system, so it could prove to be economically justified.

Sometimes too much energy can be generated by wind farms; this could cause overloading problems in the electricity grid. AEMO has the power to make wind farmers limit their generation at such times.

The proportion of electricity that can be generated by wind before problems relating to variability of supply become intolerable has been debated for years. The magazine Wind Power Monthly reported that Denmark generated 31.5% of its power by wind in January 2008 (apparently January is its windiest month) and had generated even more in January 2007 (35.5%). Even more importantly, the article stated that there had been no need to constrain production from the turbines at any time.

Sustainable energy must be diversified; we need to develop alternatives such as solar and wave energy as well as wind. When an area is covered by a meteorological high pressure area, and consequently has light winds, there is a good probability that the sun will be shining and solar power output will be high. (See Solar complements wind.)
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A part of the answer to the intermittency of the wind would be to use electricity when it is abundant to desalinate seawater. Australia has major water supply problems; in SA these are particularly severe on Eyre Peninsula (which has excellent wind resources). It should be possible to set up desalination plants to run when there is excess electricity. Electricity can not easily be stored, but water can be, readily and cheaply. Why not have the desalination plants organized so that they switch on when power is abundant and switch off when the power supply declines? Using wind power to desalinate water on Eyre Peninsula is discussed in Eyre Peninsula Water.

Improved wind forecasting would provide forewarning of changes in the quantity of wind-generated electricity entering the grid.



Regional variation in wind power generation
Does the wind blow in one state when it is calm in another?

 
Are NSW wind farms generating when SA wind farms are becalmed?
Regional variation
Graph credit: Paul McArdle and WattClarity
The graph on the right, from WattClarity, shows that about 80% of the time, when wind farms are producing little power in South Australia, they are producing substantially more power in NSW, and vice-versa.

There are 39 data points in the marked area of the graph: 39 days when there was low wind farm output in both SA and NSW.

The total of the data points, or days, in the whole graph is 200.

So, while there were 39 days in which there was low wind farm output in both states, there were 161 days in which there was not!

That is, there were four times as many days when low wind generation in one state coincided with significantly higher generation in the other state than days with low generation in both states.



 
Edited 2013/09/12

The reliability of wind power

 
Wind Farm – turbines operable
Number of turbines on-line
The number of turbines operational and capable of generating electricity at Macarthur Wind Farm
Image credit: Vestas
Wind turbines are 97-99% reliable. "The term reliability is generally used in energy policy circles as 'a measure of how long a period of time occurs between failures of the machine or how long those failures last'. Wind turbines are extremely reliable. They generally have reliability ratings of 99 per cent or more." (From The Australia Institute, Wind Farms: The facts and the fallacies.)

 
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The graph on the right records the start-up period of Macarthur Wind Farm. Note that as soon as all the turbines were on-line for the first time (about 2013/01/08) there were only very short periods when one or possibly two turbines were not operable; demonstrating their reliability.

Reliability is often confused with variability, especially by opponents of wind power.

In regard to the amount of power a particular wind farm will supply to the grid at any time: "wind farm operators ... estimate the wind farms energy output one hour in advance for each 5 minute period of supply. This is successfully achieved by using sophisticated short term forecasting models that interpret weather information as it affects the wind farm in real time." (From the Ceres Project FAQs.)

There is an informative article on the reliability of wind power on Into The Wind, the American Wind Energy Association blog. For example, it showed that Germany, which gets 10% of its electricity from wind power has a power system that is the most reliable in Europe and has a 'reliability score' 16 times better than that of the USA. The German system is also four times more reliable than that of France; which relies heavily on nuclear power.



Wind turbines shut down when the temperature goes above 43 degrees

From Terry Teoh of Pacific Hydro:
"Wind generators have a high temperature alarm at around 43 degrees and will shutdown at around 45 degrees to protect components. That's measured at the nacelle 70m above ground. At Challicum Hills (near Ararat) during 2004 our wind farm experienced 15 minutes of unavailability due to high ambient temperature. That's 0.003% of the year."
It was reported in The Adelaide Advertiser on 12th February 2006 that the operators of the Lake Bonney Stage 2 wind farm said that all its 46 turbines shut down on January 22nd when temperatures exceeded 40C. (It seems that the turbine fire on that day was not due to a turbine overheating but to an electrical fault during maintenance.)

Temperatures above 43° are rare where wind farms are built, and often occur on calm days when turbines are either not working or working at low capacity.



Bats killed by wind turbines

 
Bat photo
Photo borrowed from the Zoonosis Net site
 
Altered 2013/11/10
A study by Mark Hayes and published in the journal BioScience found that the probable number of bats killed by wind turbines across the USA in 2012 was over 600 000. An article was published on this in the Science Now in the Los Angeles Times, and elsewhere. The LAT article noted that bat numbers were "decreasing due to changing climate and diseases such as white-nose syndrome".

 

Bat death mitigation strategy

It seems the number of bat deaths can be substantially reduced while losing little power generation by reducing the cut-in speed of the turbines, see below.
 

Comparison with bird deaths

A study gave annual bird deaths due to wind turbines as 17 000 and due to feral cats as 116 000 000. How do total bat numbers compare to total bird numbers?
600 000 is a huge number, but I had absolutely no success in putting it into perspective by searching on the Net. How many bats are there in the USA? How many have been killed by white nose syndrome? How many are lost due to habitat destruction? How many die due to changing climate? There seems to be a data vacuum.

The US Geological Survey in cooperation with the US Fish and Wildlife Service produced a report titled Bats and Wind Energy – A Literature Synthesis and Annotated Bibligoraphy in 2012. Three of the points it gave were:

  • Bat-fatality rates range from just below one bat per installed megawatt per year to as high as 70. (P 16)
  • The magority of bats appeard to be killed on low wind-speed night when power production was proportionally low but turbine blades were still moving, often at or close to fully operational speed. (P 17)
  • Studies in Canada and the United States have independently shown that curtailment, or preventing turbine blades from terning during relatively low wind speeds in late-summer and autumn, can reduce bat fatalities by as much as 40-90 percent. (P 17)

Little research seems to have been done into this potential problem in Australia. It seems there is a great need for research.

I believe that Brett Lane and Associates of Melbourne wrote the wind industry's 'best practice' guidelines on bat and bird monitoring.

 
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Some further information was available at Safewind (link no longer available). This page indicated that the greatest problem is with migratory species, presumably because they fly higher than hunting bats.

Iberdrola Renewables, Acciona, and BP have bat concerns over several USA wind farms that they were intending to develop. It seems that the Indiana bat, an endangered species, has suffered from 'white noise syndrome', and there is concern that wind farms might prove a problem to the species.

Wikipedia discusses bat impact in its article on the Environmental effects of wind power. Wikipedia stated that "In April 2009 Wind Energy Cooperative released initial study results showing a 73% drop in bat fatalities when wind farm operations are stopped during low wind conditions, when bats are most active." There would be little loss to the turbine operators in stopping the turbines at such times, in areas where bat fatalities are a problem, because very little power is generated in low winds; see Wind speed range of turbines. (More on this below.)

Death by barotrauma

 

Link; Bat fatalities at two wind farms in Tasmania, Australia: bat characteristics, and spatial and temporal patterns

Published in the New Zealand Journal of Zoology, 2012/11/27, by C L Hull and L Cawthen; Sustainability and Safety Group, Hydro, Tasmania, Australia; School of Zoology, University of Tasmania, Australia; Cooperative Research Centre for Forestry, University of Tasmania, Australia
An article printed in the New Scientist, 25th August 2008, discussed a new study by Erin Baerwald and colleagues of the University of Calgary in Canada that showed that many bat deaths at wind farms were caused by the sudden drop in pressure near wind turbine blades. This causes the bats' "delicate lungs to suddenly expand, bursting the tissue's blood vessels. This is known as a barotrauma, and is well known to scuba divers". The study's data suggested that this was the sole cause of 50% of the bat deaths examined in southern Alberta, and was at least a contributing cause in 90% of deaths. The article can be read at New Scientist.

On 2012/04/19 I discussed this research with Dr Cindy Hull, who has studied bird and bat kills in relation to the Bluff Point and Studland Bay wind farms. She informed me that in her opinion the 'death by barotrauma' question was not settled. Later, in a paper published in the New Zealand Journal of Zoology, and on the same subject, Dr Hull stated that collisions were thought to be the primary cause of fatality; referring to:

  • Grodsky SM, Behr MJ, Gendler A, Drake D, Dieterle BD, Rudd RJ, Walrath NL 2011. Investigating the causes of death for wind turbine-associated bat fatalities. Journal of Mammalogy 92: 917 925.
  • Rollins KE, Meyerholz DK, Johnson GD, Capparella AP, Loew SS 2012. A forensic investigation into the etiology of bat mortality at a wind farm: barotrauma or traumatic injury? Veterinary Pathology 49: 362 371.

Note that if 50% of the bats were killed solely by barotrauma and barotrauma was a contributing cause of death in 90% of deaths then it follows that the bats killed by this cause must have to fly quite close to a moving blade to be injured by barotrauma. If it were not so then one would expect higher percentages of deaths to be due to barotrauma.

Reducing bat deaths by increasing turbine cut-in speed

University of Calgary biology professor Robert Barclay co-authored a paper with PhD student Erin Baerwald and Jason Edworthy and Matt Holder of TransAlta Corporation on this (September 2009):
"Scientists at the University of Calgary have found a way to reduce bat deaths from wind turbines by up to 60 percent without significantly reducing the energy generated from the wind farm. The research, recently published in the Journal of Wildlife Management, demonstrates that slowing turbine blades to near motionless in low-wind periods significantly reduces bat mortality."

An article by Edward B Arnett, Manuela MP Huso, Michael R Schirmacher and John P Hayes published in Frontiers in Ecology and the Environment, 2011 recorded research in which it was found that bat mortality was substantially reduced by slightly increasing the turbine cut-in speed. The authors suggested that this could be done at times of greatest likelihood of bat deaths with little effect on power generation.

In 2013 Edward Arnett, Gregory Johnson, Wally Erickson, and Cris Hein published the report: A synthesis of operational mitigation studies to reduce bat fatalities at wind energy facilities in North America. This pulled together conclusions from a number of field studies in which researchers recorded bat fatalities while experimenting with cut-in speeds.

Bats cannot fly at wind speeds much greater than around 4m/sec, the normal cut-in speed of wind turbines. Turbines generate very little power at such low wind speeds, so increasing the cut-in speed to, say, 6m/sec. for some time would result in little loss of generation.



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Honey bee problems?

Some people have claimed that wind turbines cause (so far as I know, unspecified) problems to bees, which then are unable to pollinate the plants that rely on them for this service.

I have not read any half-way convincing evidence to support the truth of this claim, and find it very hard to imagine how it could happen. Bees would very rarely, if ever, fly high enough to be hit by a turbine blade.

I add the point to this page as an example of one of the difficult to credit claims being made against wind turbines with no apparent basis in reason or science.

There are well known problems occurring in the world's honey bees; varoa mites and colony collapse disorder among the more prominent of them. Separating pollination problems, or bee number reduction problems caused by wind turbines, from these much better researched and credible problems, would require careful research, and I have not heard that any such research has been done.



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Wind farms cause power surges?

Apparently, if wind power becomes a major component (say greater than 10%), power surges due to gusting of wind at wind farms can, theoretically, cause problems in a power grid.

I believe that regulations imposed on the operators of wind farms in Australia do not allow major power surges. The wind farm operators have to put in place devices stopping power surges entering the electricity grid.



A misty Autumn morning at a wind farm
Turbines in mist
North Brown Hill Wind Farm, Mid North South Australia


Can a wind farm change the local climate?

Can wind farms affect rainfall?

(Possible effects on temperatures and increased turbulence are discussed elsewhere on this page.)

A farmer from an area downwind of a proposed large wind farm expressed concern to me that the slowing of the wind might cause greater rainfall at the wind farm and less rain downstream. At first it seemed unlikely to me that any effect would be significant, but on more investigation some interesting points started showing up.


Relief rainfall

From Wikipedia: "Orographic or relief rainfall is caused when masses of air pushed by wind are forced up the side of elevated land formations, such as large mountains." Wind farms on the tops of ridges will have the effect of making the ridges 'appear' to the air-flow to be a little higher; it would therefore be very reasonable to expect an enhanced orographic effect.

When a wind turbine takes energy from the wind flowing through it, it slows that wind down. A bit of thought then shows that for the same volume of air to pass a point in the same time, but at a lower speed, it must take up more space. Putting it another way; if you think of a cylinder of air the diameter of the turbine blades approaching the turbine, then the velocity of the same air slowing as it passes through the turbine, the diameter of the cylinder on the down-wind size has to be bigger because the velocity is lower and the same amount of air per unit time must pass through it. The slow-moving air on the down-wind size of the wind farm will take up more space than the higher-speed wind would have before the wind farm was built, so this will cause the air-mass above to rise a little higher to pass over the obstruction.

In Australia, I suspect that most people will think that a slightly increased local rainfall is a very good thing. On the other hand, it would mean that there would be a little less moisture in the air that moves away from the wind farm into other areas.

How much will a wind farm increase the effective height of a ridge?

In 2009 the rotor heights of typical wind turbines are about 80m above local ground level; a typical spacing seems to be about four turbines per linear kilometre along ridge lines; rotor diameter is about 90m. So looking across the ridge the turbines take up 4×90m=360m in every 1000m, or about 1/3 of the profile. A modern wind turbine takes up to about 30% of the energy from the wind that passes through it (the theoretical maximum, the Betz limit, is 59%). It seems to me that something in the order of 10 to 20m of effective height added to the ridge would be reasonable; but that is more quess than estimate. Of course if there was more than one row of turbines the effect would be stronger.

An example case

The Clare 'Valley', an elevated area in Mid North South Australia famous for its high quality wines receives significantly higher rainfall than the surrounding, lower, areas. Roughly, the Clare Valley gets about 600mm annual average while the lower country gets around 400mm. The higher ridges around the Clare Valley are 470m to 550m in altitude.

Snowtown wind farm is built on the top of the north-south trending Barunga Range which is roughly 50km to the west of Clare. The top of the Barunga Range is around 325m. Most of the rainfall in the Clare Valley comes from the west; that is, quite a bit of it passes over the Barunga Range.

If the wind farm has caused the effective altitude of the Barunga Range to increase from 325m to 345m it would seem likely that this will cause a little more rain near the Barunga Range with correspondingly less remaining for the Clare Valley. (From being about 65% as high as the Clare ranges, the Barunga Range has effectively gone to 69% as high.)

To calculate very roughly what this might mean to the local rainfall we can make some very simple assumptions and employ a little basic arithmetic. Supposing that there is a linear function relating rainfall to altitude in the Clare region. We know that rainfall is about 400mm at 100m altitude (the plain between the Barunga Range and the Clare Valley) and is 600mm at 400m (typical of the Clare 'Valley'). Then we can derive an equation: rainfall = 0.667 × altitude + 333; the slope of the function being 0.667. So an increase in the effective altitude of the Barunga Range of 20m should result in a increase in local rainfall of around 0.667×20=13mm per annum.

Research into the significance of this effect would be useful.
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Altered 2013/01/06

Can wind farms affect temperatures?


 

Distinction from climate change/greenhouse warming

It is important to note that any warming from the changes to the air flow due to wind turbines will be very local and there will be no net increase in heat. This is all about some redistribution of local heat; no more than that.

By reducing the need for the burning of fossil-fuels to generate electricity wind farms will reduce climate change/global warming.

There is some research indicating that local temperatures can be increased by wind farms. It seems logical that a slight local temperature increase might follow from the lowering of wind velocity due to the turbines; the wind takes some of the heat from the soil, animals, buildings, etc. Slowing the wind would reduce this effect.

Turbulence from wind turbines will also cause some changes in the local temperatures. The turbulence increases the mixing of the air at very low levels with that at higher levels.

Nature Climate Change, one of the Nature Publishing Group, published a paper by Liming Zhou, Yuhong Tian, Somnath Baidya Roy, Chris Thorncroft, Lance F. Bosart and Yuanlong Hu, titled "Impacts of wind farms on land surface temperature". It was published online 2012/04/29. "Here we present observational evidence ... based on analyses of satellite data for the period of 2003-2011 over a region in west-central Texas, where four of the world's largest wind farms are located". The results of the study "show a significant warming trend of up to 0.72°C per decade, particularly at night time, over wind farms relative to non-wind farms".

The 'per-decade' part of the statement is misleading, as the satelite data only showed a rise in temperature, not a continuing trend. Apart from this the slight surface temperature rise should surprise no-one; earlier research (2004, S. Baidya Roy and S. W. Pacala) has shown a similar effect and if looked for, it probably would be found downwind of any tall structure that causes turbulence, such as grain silos.

At night time a layer of cool, calm air can develop close to the ground. The turbulence from nearby turbines, or other tall structure, can cause the warmer air above to mix with this cool layer; increasing temperatures at the surface. These higher temperatures, and increased air movement over the surface, can increase moisture loss from the soil.


Turbines increase the 'surface roughness' of the land

Wind blowing over bare flat land moves with little friction. Wind blowing over forested land is much more affected by the friction in the lower layers due to blowing through the trees. Wind farmers talk of the degree of 'surface roughness' and its effect on wind flow.

An array of turbines will have an effect on wind flow similar to that of trees, they will slow the wind at lower levels due to the energy that they take from it and the turbulence that they cause.

In many parts of the world trees and forests have been cleared from huge areas; Australia has lost a very large proportion of the scrub, woodland and forest that it once had in its agricultural areas. Will the introduction of wind farms change the 'surface roughness' back to nearer what it was before the trees were cleared?

Again, research into the likely effects on weather should be carried out.


Links/research on wind turbines and weather

In a Net search I was unable to find any research into the likely or actual effect of on-shore wind farms on local rainfall. This seems to be a significant lack.

Pim Rooijmans, of Utrecht University, did a master's thesis on the "Impact of a large-scale offshore wind farm on meteorology"; a 3MB pdf file was available, but no longer is. Rooijmans wrote of a reduction in rainfall in one rainfall event in one place, of more than 50%, but increased rainfall elsewhere. Rooijmans' figures were based on computer modelling rather than actual events.

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"Weather response to management of a large wind turbine array" by D.B. Barrie and D.B. Kirk-Davidoff (3.4MB) can be downloaded at www.atmos-chem-phys-discuss.net/9/2917/2009/acpd-9-2917-2009-print.pdf. It discusses modelling of the effect of a continent-scale wind farm on US weather.



Turbulence from wind turbines

 
Turbulence from turbines
Image of turbines at the Danish Horns Rev offshore wind farm; kind permission of Thomas Bak. "Unique meteorological conditions on 12 February 2008 at 1300 hours resulted in the wind turbines creating condensation (i.e. clouds) of the very humid air, thus making it possible to see the turbulence pattern behind the wind turbines."

I'm told that this is a pretty legendary photo throughout the wind farm industry, a great example of the need to site turbines so the prevailing wind is not blocked by the turbine in front.

Buildings, trees and hills would have a similar effect

I have seen this photo used to 'prove' that turbines produce turbulence that could be deadly to light aircraft and would seriously interfere with crop spraying. Lamina flowing wind, as on the upwind side of these turbines, is probably uncommon on land, especially land that has trees and hills. Turbulent winds, probably similar to those on the downstream side of these turbines, are very common over land.

Unique photo

There seem to be no photos similar to this on the Internet. This fact strongly suggests that the conditions under which this photo was taken, a lamina (smoothly flowing) wind with a very low sea mist and wind turbines, must be very rare.
 
Updated 2013/06/15
It has been suggested that the turbulence caused by wind turbines causes increased mixing in the lower layers of the air and that this has an affect on the local weather.

The New York Times published an article that discussed research published in The Journal of Geophysical Research; lead author, Dr. Somnath Baidya Roy. These researchers, using simulations, found that:

"In the Great Plains [of the USA] there is a nighttime stream of fast-moving air that separates cool, moist air near the ground from drier, warmer air above. The simulation found that the [hypothetical] turbines catch this nocturnal jet, and the ensuing turbulence causes vertical mixing."
This would cause more drying of the soil than would happen otherwise, and would also have implications for heating or cooling of homes. Roy suggests a solution – create better rotors. "We found that low-turbulence rotors are more economically efficient, they tend to generate more electricity than conventional rotors," he said.

The researchers said that:

"During the day, the effects from the disturbed airflow are negligible, since natural turbulence mixes the lower layers of the atmosphere. But the researchers found that in the predawn hours, when the atmosphere is less turbulent, a large windmill array could influence the local climate, raising temperatures by about 2 degrees Celsius for several hours. The rotating blades could also redirect high-speed winds down to the Earth's surface, boosting evaporation of soil moisture."

Informative links

Windlab have researched turbulence and its effects on wind turbines.

This video clip, taken from a light aircraft, shows wind turbines operating in low cloud, but without causing any apparent turbulence.

Turbine wake plumes and aircraft movements

As the above photograph shows, turbulence from wind turbines can extend a considerable distance downwind from the wind farm. Aviators in Australia have expressed concern about this, especially in regard to nearby airports or airstrips. Another section on this page deals with light aircraft and wind turbine turbulence.

 
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An anti-wind farm speaker at a meeting I attended used the above photo to suggest that wind turbines could kill birds by barotrauma at large distances from the blades; an absolutely ludicrous claim. Apart from the fact that birds are less susceptible to barotrauma than bats, even bats are only affected when very close to the blades, and there is no reason to believe that the turbulence in the photo is at all violent.



 
Updated 2012/01/08

The energy consumed in construction of a wind farm is very much less than the energy that farm will produce

Some wind power detractors have claimed that more energy is used in constructing wind turbines and building wind farms than is saved by the wind turbines displacing fossil-fuel fired power stations. Investigation shows that this is false. (I have included several references and one calculation of my own in the discussion below; it can be seen that all come to similar conclusions.)

 

A calculation of the embodied energy in the steel of a turbine tower

From the Victoria University of Wellington, NZ, page on embodied energies we have the starting point that the embodied energy in virgin (not recycled) steel is 251 200 MJ/m3. Taking the diameter of the tower as 3m, the height as 80m and the wall thickness as 40mm (0.04m) we can calculate that it contains 30 m3 of steel, giving an embodied energy of 7 576 GJ. The rated power of the turbine is 2.1 MW and the capacity factor from Wind power in Australia is 34% giving an average generation of 0.714 MW achieved. From Energy units we have 1 MJ = 0.278 kWh; (therefore 1 GJ = 0.278 MWh). Based on these figures it is simple to calculate that the embodied energy in this tower would be recovered in 122 days of turbine operation; about four months.

Note that if recycled steel was used in the construction the pay-back period would be much reduced.

I would think that the greatest part of the embodied energy in a wind farm would be in the steel of the towers.

The peer-reviewed journal Renewable Energy published a paper titled Life cycle assessment of a multi-megawatt wind turbine written by Martinez, Sanz, Pellegrini, Jimenez and Blanco. It stateed that "during its lifetime, the wind turbine allows us to recover nearly 31 times the environmental contamination caused by its manufacture, start-up, operation and decommissioning."

The same journal, Renewable Energy (20 [2000] 279-288), published a paper by L. Schleisner, titled 'Life cycle assessment of a wind farm and related externalities'. Schleisner discusses two hypothetical wind farms, one offshore and one land-based. He concluded that the energy pay-back time for the offshore wind farm would be 0.39 years and for the land-based wind farm 0.26 years; both being less than 2% of the assumed 20-year lifetime of the wind farms. The journal Renewable Energy has an impact factor of 2.2.

The Danish wind turbine manufacturer Vestas report in a "Lifecycle Assessment of a V90-3.0 MW onshore wind turbine" that it will typically 'pay back' the energy consumed in the whole life of the turbine in 6.6 months. Their lifecycle assessments are available on the Internet.

Suzlon, another wind turbine manufacturer, estimated in regard to the Brown Hill Range Wind Farm in SA that 'the payback period of "embodied energy" of the whole wind farm is approximately 5 months'.

The technical term for the amount of energy consumed in the process of obtaining energy compared to the energy obtained is Energy Return on Investment (EROI) and I have covered this in some detail in Wind power. In the study discussed there, wind farms, on average, produce around 18 times as much energy as is used in their construction. One would expect that this figure will increase as wind farms operate for longer periods and as the technologies mature; indeed, given an energy payback period of six months and a (conservative) turbine life of 20 years one can calculate an EROI of 40 (neglecting any energy involved in repairs and maintenance).
 
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Pacific Hydro have stated in a publication that "on average it takes only two to three months for a wind turbine to recover all the energy required to build it".

A publication of Wind Energy (Denmark) dated December 1997 states that the energy payback time for a 600 kW turbine is 3.1 to 3.8 months.

The related question of the carbon dioxide balance of wind farms is covered on this page in CO2 and wind farms.



How much power do turbines use when they are not generating?

One of the more foolish claims made by some people who are opposed to wind turbines is that they use about as much power when they they are not operating as they generate when they are running.

A little thought will show anyone with any grasp of engineering at all that this is a crazy claim, but what is the fact?

Lane Crockett, head of Pacific Hydro, has informed me (2014/06/12) that "a typical 2 MW wind turbine will use about 5 kW when not spinning". To put this into perspective, the same turbine, in eastern Australian conditions, will generate a long term average of around 700 kW.

Power generated from all AEMO monitored wind farms in Australia, 2012/01/15, shown individually.
This graph, from a typical day's wind farm operation, shows that most wind farms are generating most of the time. (That is, most of the coloured lines are not right on the bottom of the graph.)
All wind farms
Graphic credit: http://windfarmperformance.info
The Y-scale is capacity factor, the X-scale is time in 24-hour notation.
Each coloured line records the output of one wind farm.



The CO2 released from the manufacture of the cement used in the concrete bases of wind turbines is comparatively small

This relates to another claim that has been made by wind farm opponents that seems to be completely without any basis in fact. The calculations below show that the CO2 released into the atmosphere during cement manufacture is 'payed-back' in the first day or two of turbine operation.

Around 150 tonnes of concrete are used in the foundations of a single wind turbine. Cement manufacture releases large amounts of CO2 to the atmosphere. Is this pollution comparable to the CO2 abatement resulting from the wind farm's electricity replacing coal-fired electricity?

Also see CO2 and wind farms, which deals with the total amount of carbon dioxide released from wind farm construction, elsewhere on this page.

Joseph Davidovits, Geopolymer Institute, Saint-Quentin, France stated:

"Studies have shown that one ton of carbon dioxide gas is released into the atmosphere for every ton of Portland cement which is made anywhere in the world."

From McCaffrey "The Cement Industry's Role in Climate Change" (the link, http://www.propubs.com/climate/climate.html, is no longer working), one can calculate that for each tonne of cement that is manufactured, about 0.9 tonnes of carbon dioxide is released into the atmosphere.

The Information Unit on Climate Change, Switzerland, states that about a half a tonne of carbon dioxide is released from the roasting of the raw materials for each one tonne of cement manufactured. This does not include the carbon dioxide released from burning fuel.

Placing tower on concrete footing
Placing the bottom section of a wind turbine tower on its concrete footing
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How much CO2 is released for each wind turbine?

From the above we could work on 0.9 tonnes of CO2 for each tonne of cement, as a rough figure. A publication of Pacific Hydro states that each of their 1.5 MW turbines at the Challicum hills had 150 tonne foundations. Working on 10% of the foundations being cement (the remainder sand, gravel, steel and water) this gives a figure of 15 tonnes of cement resulting in the release of 13.5 tonnes of CO2 to the atmosphere.

Pacific Hydro state that the CO2 abatement due to the power production of each of their 1.5 MW turbines is 5000 tonnes per year (13.7 tonnes per day). My calculations confirm those of Pacific Hydro.

 

Carbon dioxide released per MWh of coal-generated electricity

Figures from The Australian Greenhouse office are that the current best efficiency for brown coal-fired power stations in Australia is 1220 kg CO2/MWh of sent out electricity, and for black coal 861 kg CO2/MWh.
Working on a round figure of 1 tonne of CO2/MWh for coal-fired electricity generation and a 35% load factor for a 1.5 MW wind turbine we can calculate

  • The actual (or average) power generated by a 1.5 MW turbine would be about 0.53 MW.
  • CO2 abatement for this turbine would then be 0.53 tonnes per hour.
  • This equals 12.6 tonnes per day or 4600 tonnes per year; very close to the Pacific Hydro figure above.

Conclusion

If these figures and calculations are correct, the 13 or 14 tonnes of CO2 released from the manufacture of the cement is paid back in the first, or early on the second, day of turbine operation.

Turbine footing or foundation

Since doing the above calculations I have been informed (May 2007) by Peter Reed of Suzlon (Australia) that while 216 tonnes of concrete is sufficient for the footings of the Suzlon 2.1 MW turbines being constructed at Hallett Wind Farm (where they are able to use rock anchors), 800 tonnes of concrete would be required for a 'gravity footing' for the same turbine. I believe this would be used where the turbine was to be constructed in an unconsolidated sediment foundation. Less than a week of operation would be required to 'pay back' the CO2 released from the manufacture of the approximately 80 tonnes of cement in these 800 tonne footings.


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Altered 2014/06/25

Abatement: CO2 and wind farms
Wind farms greatly reduce carbon dioxide emissions

 
Emissions intensity on the Australian NEM
Emissions intensity
Graph credit – Professor Mike Sandiford, University of Melbourne; data from the Australian Energy Market Operator (AEMO)
The graph on the right shows emissions intensity (EI) from the four large states in the Australian National Electricity Market (NEM) and the average for the whole of the NEM, including Tasmania. Tasmania's EI is off-scale at the bottom of this graph.

Note the very large decline in South Australia's EI; due almost entirely to the introduction of wind power. Much of this reduction is due to far less use of the state's only remaining coal-fired power station, the Northern, which, as of 2013, was being run for only the warmer half of each year. Its declining capacity factor is shown elswhere on these pages.



 
Changes in emissions
Graph credit – CEDEX report by Pitt and Sherry.
The graph on the right suggests that emissions were effectively decoupled from electricity generation in the National Electricity Market (NEM) in about late 2009.

Wind power in Australia became significant in around 2003 and steadily increased to 2013.

 
Changes in generation by fuel type
Graph credit – CEDEX report by Pitt and Sherry.
This graph shows the steady increase in renewables (mostly wind power) and the particularly marked decrease in power from black coal-fired power stations. The decline in brown coal has been less because it electricity generation from brown coal tends to be less expensive than from black coal.

Wind turbines have a carbon intensity similar to those of biomass-energy and hydro-power; it is a small fraction of that of the fossil fuel-fired power generators. Wind power is one of the best available methods of generating electricity while minimising greenhouse gas production.

 
Carbon intensity of various electricity generating methods
MethodSovacoolWeiser
 g CO2e/kWh
Biomass14-4174
Coal9601000
Gas 540
Hydro108
Lignite 1100
Nuclear6610
Oil 760
Solar PV 56
Wind(on-shore) 1012
Sovacool, B.K.; Valuing the greenhouse gas emissions from nuclear power: A critical survey. 2008. Energy Policy; 36: 2940-53 and Weisser, Daniel; A guide to life-cycle greenhouse gas emissions from electric supply technologies.
Some who object to wind farms claim that the amount of CO2 released during wind turbine manufacture and wind farm construction is greater than the savings that result from wind farms displacing fossil-fuelled electricity. This is one of their more ludicrous claims and is quite demonstrably false.

The Australian Energy Market Operator (AEMO) in the draft 2011 South Australian Supply and Demand Outlook report showed that emissions from electricity generation in SA declined by about 20% over the same period as generation by wind farms increased from near zero to 20% of total generation. See their graph.

The Australia Institute is an independent public policy research centre funded by grants from philanthropic trusts, memberships and commissioned research. It has a pdf document about The facts and fallacies of wind power. In this document The Australia Institute's researchers stated that taking into consideration all the CO2 released during manufacture, construction and management of a wind farm, every megawatt-hour (MWh) of wind farm electricity comes with a carbon cost of 14kg of CO2 while coal-fired electricity comes with a carbon cost of around one tonne of CO2 per MWh.

They further state that:

"the emissions related to the manufacture, construction and operation of the wind farm are likely to be equal to less than two per cent of the emission reductions that arise as a result of the displacement of fossil fuel-based electricity generation."


How much CO2 does wind power save?

 
Also see CO2 and wind farms on this page and CO2 abatement on the Wind-home page.
In July 2006 consulting firm McLennan Magasanik Associates Pty Ltd produced a report titled 'Assessment of Greenhouse Gas Abatement from Wind Farms in Victoria' for Sustainability Victoria. The report concluded that around a tonne of greenhouse carbon dioxide would be abated for each megawatt-hour of wind-generated electricity. (Effectively, for each MWh of wind energy generated about one MWh less 'dirty' coal-fired power would be generated.) Under some circumstances even more 'dirty' power would be abated than 'clean' power generated.

 
The Guardian (UK) published an interesting piece titled "It's a myth that wind turbines don't reduce carbon emissions" by Chris Goodall and Mark Lynas on 2012/09/26.
Three scenarios were modelled:

  • No additional wind generation capacity in Victoria (apart from that already installed)
  • 100 MW of additional wind generation, with the average capacity factor of the additional generation being 35%.
  • 1000 MW of additional wind generation, with the average capacity factor of the additional generation being 33%.
The two scenarios that included wind energy resulted in the reduced CO2 emissions shown in the table below.

Average abatement intensity from wind generation, kt CO2e/GWh
Wind Capacity2007200820092010201120122013 20142015
100 MW0.950.920.940.930.950.950.93 0.910.88
1000 MW1.121.101.081.091.091.101.05 1.031.06

Put simply, in the Victorian situation, for every MWh of power generated by a wind turbine about a tonne less CO2 will be released into the atmosphere than would be without the wind power. See the McLennan Magasanik report for a full explanation.

A single, typical 2 MW wind turbine operating at a typical capacity factor of 35% will generate around 6 000 MWh each year and save about 6 000 tonnes of CO2 from entering the atmosphere each year. A typical wind farm of 30 turbines will save 180 000 tonnes of CO2 each year.

Decoupling of electricity generation and emissions
Electricity generation and emissions
Note that starting in late 2009, when wind power capacity on the NEM (National Electricity Market, eastern Australia) started becoming substantial, emissions decoupled from generation.
Graph credit – Hugh Sadler, CEDEX report by Pitt and Sherry.


I have written about the energy consumed in wind farm construction and my own investigation into the amount of CO2 released from wind-farm concrete elsewhere.


Visual objections to wind farms
Brown Hill Range Wind Farm
Turbines of Brown Hill Range Wind Farm, Hallett

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Visual objections to wind farms

 
Our perception of wind turbines affects our attitude and our attitude can have important consequences to ourselves should we live near turbines.
"Beauty is in the eye of the beholder". So is ugliness. Some people like the look of a row of wind turbines slowly turning on the top of a ridge, others find them offensive. It is, of course, insupportable to claim that one group is right and the other wrong.

Almost everyone agrees that there are some places – particularly areas of great natural beauty – where wind turbines should not be built. I can't imagine that anyone would suggest that a row of wind turbines on top of the Wilpena Pound Range in the Flinders Ranges would be desirable.

 
Clements Gap WF
Clements Gap Wind Farm
How we perceive wind turbines visually depends in part on whether we believe that they are, in themselves, desirable and useful. Those who see turbines as a part of the answer to the greenhouse/climate change problem are more likely to consider them beautiful, those who think wind-generated electricity is over-rated or that either climate change is not happening or is not due to Man's activities are more likely to see turbines as intrusive and ugly.

In an article about the proposed Merredin Wind Farm the Merredin Mercury printed the following:

In a study in Geographical Research published by Wiley-Blackwell, it was found wind farms have a negative impact on landscapes with a high scenic quality, but a positive effect on dull and mundane landscapes. Author Dr. Andrew Lothian said while people may be apathetic to the appearance of wind farms, their location is critical. "Wind farms in scenic areas, particularly the coastal areas, are regarded as damaging to the landscape," he said. "However, in agricultural areas of low scenic quality, wind farms seem to beautify the otherwise mediocre surroundings."

Also see Air navigation lights, below.



Air navigation lights
Brown Hill Range Wind Farm
Air navigation lights at dusk, Brown Hill Range Wind Farm as seen from 50km south at Clare.
There is no need, either for safety or in law, for the lights to be so bright. AGL had them switched off around the end of 2009.

 
Altered 2012/03/27

Air navigation lights

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In researching wind farms I have found that one of the biggest concerns Australians have with them, at least in northern SA, is the brightness of the air-navigation lights. The beautiful pristine starry nights that we are used to in rural Australia are not improved by a line of bright red flashing lights on the horizon.

In Denmark and New Zealand lights on wind turbines are one hundredth the brightness of many of those used on Australian turbines.

The air-navigation lights on the first two of the Hallett wind farms, 50 kilometres away from my place in the Clare hills, were not only visible to me, they were conspicuous (photo above). If I walked about 1km west I could see another line of red flashing lights, this time of the Snowtown Wind Farm, 40km away. (The lights of Snowtown Wind Farm are also conspicuous from Crystal Brook, about 40km to the north.) (All of these lights have since been switched off [2012/03/27].) Whether an individual finds the lights objectionable or not is a matter of that individual's perception.

In Australia the Civil Air Safety Authority (CASA) decides how bright the lights must be when the turbines are in the vicinity (approximately 30km) of an aerodrome.

"CASA cannot mandate the lighting or marking of structures outside the vicinity of aerodromes. It is CASA's view that this is a decision for, and the responsibility of, the developer" (pers com Paul Trotman, CASA)."
CASA did publish an Advisory Circular (AC 139-18) to provide guidance to wind farm developers, this has since been withdrawn.
"Mr Byron (Chief Executive Officer, CASA) has ... directed that CASA now undertake an appropriate safety study into the risk to aviation posed by wind farms and develop a new set of guidelines."
 
Light-emitting-diode (LED) lights that concentrate their output in the horizontal direction are available and are preferable to lights with a broader spread. The former have been used at Wonthaggi and the latter at Challicum Hills.

There is no air safety necessity for the lights to be so bright that they are conspicuous at 50km. Being easy to see from 5km would be quite enough for air safety; using the inverse-square law of illumination this would require only one hundredth the present brightness in the lights. Indeed, I have been informed that while CASA advised the use of lights of 2000 candela on tall wind turbines in Australia, the New Zealand authority holds that lights of 20 candela are acceptable at Tararua III Wind Farm, even near an airfield (Terry Teoh, Pacific Hydro, pers. com. Sept. 2008).

In Denmark 10 candela lights are used, and in Germany there are various standards, but usually blinking 100 candela lights are used. (Tobias Geiger, Westwind Energy, Global Windpower conference, Adelaide 2006)

The wind farmers must take the bulk of the blame for the bright lights. As stated above, CASA only has an advisory roll, the wind farmers could use dimmer lights without breaking any law. One can only suppose that they use very bright lights because they fear that if they used anything dimmer and there was an aerial accident, they might be sued. They don't want to take any risks with their money. If the lights annoy people, that is of less concern than the remote chance of a big law suit.

If the lights must be bright for those times when visibility is poorer, then there could be two sets of lights, one for good visibility and one for poor – with an automatic system detecting poor visibility and switching from one to the other. At least in South Australia the dimmer lights would be sufficient more than 95% of the time.

Excessively bright lights on wind turbines conspicuously contradict the need to minimise energy consumption. Having obvious wastage of energy, even if it is trivial in comparison to the total energy generated, associated with devices that are aimed at reducing greenhouse gas production seems particularly incongruous.



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Water requirement of wind farms

Wind farm objectors have claimed that wind farms consume enormous amounts of water. This is quite false. The great majority of modern wind turbines do not consume any water at all for cooling (there is one type of relatively small wind turbine that does use some water for cooling, but it is not used in Australian wind farms). Water is used on an operating wind farm for things like washing hands, flushing toilets, cleaning floors, and re-establishing native vegetation.

During construction, water is required for making the concrete needed for the footings of the towers, and for things like damping-down while road-building, but these require small amounts of water relative to those used for mining coal or uranium or cooling coal-fired, or nuclear, power stations.

Terry Teoh of Pacific Hydro informed me that in building their last three wind farms (totalling 159 MW installed) they used 36ML of water. Tim Knill of AGL estimated rather less water requirement; my own estimate was similar to Terry Teoh's figure.

For comparison I believe that a typical Australian wet-cooled coal-fired power station uses around 1.5 kL per MWh of electricity generated. The 159 MW of wind farm referred to by T. Teoh above generates about 322 GWhr of electricity per year. That amount of electricity generated by a wet-cooled coal-fired power station would require about 480ML of water. That is about 13 times as much water, every year, as was used to build the Pacific Hydro wind farms.

Comparing with agriculture might also be interesting. The average water consumption for wine-grape growing in the Murrumbidgee Irrigation Area (MIA) is 5ML/ha/year; in the Clare Valley, about 1ML/ha/year. So a single 36ha vineyard in the Clare Valley would use as much water, each year, as was used to build the Pacific Hydro wind farms. In the MIA, 36ML would only be enough for 7.2ha for one year, probably not a big enough vineyard to provide a living for a single family.

One of the greatest advantages of wind power is its very small water requirement.



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Groundwater and wind turbines

It has been claimed several times that building wind turbines could harm underground water resources.

This seems to be completely unfounded. I worked in the groundwater field for over thirty years and cannot imagine any way in which the turbines or turbine foundations could harm groundwater resources.

As mentioned under water requirements of wind farms relatively little water is used during construction and a negligible amount is used during operation of a wind farm. Wind farms displace fossil fuel power stations that often use huge volumes of water for cooling.

Of course any industrial development, including many farming developments, can lead to contamination of surface and groundwater, but I've never heard of any significant contamination due to wind farms anywhere in the world.



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Do wind farms turn away tourists?

The allegation that a wind farm will turn away tourists is one that is often used by wind farm opponents. So far as I have been able to find out there is no convincing evidence that wind farms are either good or bad for tourism. I could refer to information from the wind farm industry, but skeptics would rightly say that that could be biased. The links below are from sources that appear to be unbiased.


 

Trip Advisor; wind farms as tourist attractions

Ketan Joshi wrote an article in which he looked into how people posting on Trip Advisor rated wind farms as tourist attractions. He reported an average of more than four stars out of five.
The Scottish Government (2008/03/12) published research indicating "minimal impact on the growth of Scotland's tourism industry".


ERTP (Electronic Resources for Tourism Professionals; link no longer available) published an abstract of a paper by Cara Aitchison (University of the West of England) entitled "Lies, damned lies and wind farm survey statistics: disentangling survey methodologies and motives in tourism impact studies". She wrote
"The small scale of the research undertaken to date, the geographical specificity of each survey commissioned and the variable research methodologies employed has resulted in a fragmented research base that has left planning inspectors unable to reach a definitive conclusion on this subject."
She also mentions opponents of wind farms "use of alternative and unorthodox survey methodology which resulted in highly contentious research findings".


The Quebec Source for Information on Global Trends in International Tourism has a page by Julianna Priskin titled 'Do wind farms affect tourism?' In its conclusion Priskin states that "The few studies mentioned here suggest that even though the majority of tourists may appear positive about wind farms" and goes on to provide a cautionary note.


Turbines, fog and gum trees
Turbines, fog and gums
North Brown Hill from the west, early one Autumn morning


 
Derelict wind turbines
Photo acknowledgment – treedork, Flickr

Wind turbine litter

The Industrial Wind Action Group, an anti-wind power organisation, claims that "More than 100 broken windmills dot the landscape in California near Palm Springs".

The photo at the right is of the Kamaoa Wind Farm, Hawaii. I have no information on the length of time that the turbines remained in a neglected state.

We in Australia must take care that old, unviable wind turbines do not become a blot on the Australian landscape. The owner of the wind farm should be made to remove it when it is no longer operating. Government has a responsibility to make sure that this will be done; perhaps there should be money compulsorily held in trust accounts specifically for the dismantling of wind turbines at the end of their useful lives?

The very large wind turbines that have been used in Australia will have a high scrap value and therefore I would expect that it will be worth dismantling them for their steel, copper and other valuable components, rather than leaving them once they become unusable.



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Wind turbine blade failure

Wind turbine blades have been known to fail and break apart. This can result in pieces flying several hundred metres when the failure was caused by the turbine rotating at very high speed when its control mechanisms failed during a high wind.

The break-up of a rotating turbine is an extremely rare event. It has never happened in Australia (as of November 2013). An anti-wind power Net site (Caithness Windfarm Information Forum) records an average of about 20 blade-failure events per year world-wide (not necessarily in utility scale wind turbines). There are around 250 000 utility scale wind turbines in the world. Assuming that all 20 blade failure events recorded by Caithness were in utility scale turbines, we can calculate a probability of one turbine in 12 000 suffering from blade failure in any one year. That is, a probability of blade failure of 0.000083 in any one year, or 0.00000023 on any particular day.

So far as I have been able to find out, no one has ever been injured by a piece of a blade thrown from a utility-scale wind turbine.



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No country anywhere in the world has abandoned wind power, most of those with good wind resources are building more wind farms

Some objectors to wind power make the point that wind farms are being abandoned in Europe and the USA and that this must prove that these countries have learned that wind power is no good. It is a fallacy based on a half-truth.

The wind farms that are being abandoned are old ones, with old, out-dated turbines. Wind turbine technology has been steadily improving over the past few decades; the best turbines of twenty years ago cannot compete with modern turbines. Why keep a wind farm with out-of-date and (by modern standards) inefficient technology going when there are more efficient options?

In Esperance, WA for example, small, old, out-dated turbines have been replaced with bigger, newer ones; the capacity of the new wind farms (5600 kW) is much greater than the old one (360 kW). It's called progress!

No country that has a significant development of wind power is abandoning wind power; they are all building far more new wind power station capacity than the old that they are abandoning. Total installed wind power world-wide is increasing at an exponential rate.



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Updated 2010/11/03

Lack of transmission lines

Most reasonably intelligent Australians would realise that wind power developments in Australia have taken place where there are reliable and relatively strong winds. Fewer people realise that wind farms are also built near high-capacity power lines; there are many areas that have top-class wind resources, but are not being seriously considered for wind farm development because of the lack of transmission lines.

In South Australia, for example, southern Eyre and Yorke Peninsulas, Kangaroo Island and the Limestone Coast (south-eastern SA) would have more wind farm development if the existing transmission lines had more capacity. This problem is discussed in greater depth in Sustainable energy in Australia.

The Electricity Supply Industry Planning Council Annual report for 2009 stated that "Further development of wind in South Australia will require significant investment in networks that, at times, already struggle to cope with the transfer of high levels of wind energy, particularly in the mid-north and south-east of the State."

Governments fund and build transmission lines for coal-fired power stations and mines, but no Australian government has yet funded and built a transmission line for sustainable electricity. (Yet another indication that Australian governments are not serious about developing sustainable energy?)

Christeen Milne, Greens MLC in Tasmania, has suggested that wind power development regions (WPDR) should be identified and transmission lines built to these in anticipation of wind farm development. This would replace the present ad-hock industry growth. The US state of Texas is following a similar approach. Among other qualities required for an area to be classed as a WPDR would be for the local people to be generally in favour of wind development.

The only promising sign (as of November 2010) seems to be the Eyre Peninsula Wind Project, a proposal to build major power lines on South Australia's Eyre Peninsula to connect to major wind resource areas.



 
Updated 2013/01/28

Do wind farms replace coal-generated electricity?

A commonly heard objection to wind farm construction is worded something like "no coal-fired power station has ever been closed down because of wind farms". This claim is misleading, mischievous and as of 2012, false. The Thomas Playford Power Station at Port Augusta in South Australia has been shut down, probably permanently, largely due to the expansion of wind power in that state. Not only that, but the larger and more modern Northerm Power Station, also in Port Augusta, will likely only be used in summer in future. The Canadian province, Ontario, is to close down all its coal fired power stations, largely because of its many wind farms (see the box on the right).

 

Onterio shuts down all its coal-fired power stations

On 2013/01/11 it was noted in Scientific American that the Canadian province of Ontario was to phase out all its coal-fired power stations. The same article notes that wind and gas power will fill the gap. Ontario has 2000MW of installed wind power (compared to Australia's 2500MW, end of 2012).

Electricity generated must be consumed

Electricity that is fed into the grid at one point must be consumed at some other point; generation must always equal consumption. The moment that consumption starts to out-strip generation the voltage in the grid drops and consequently consumption declines. (For example, a toaster will consume less power at 220 volts than it will at 245 volts.) If generation begins to out-strip consumption the voltage increases and consumption increases.
Another, less misleading, statement could be made, "every kilowatt-hour of electricity fed into the grid from a wind farm is a kilowatt-hour that does not need to be generated by a fossil fuel fired power station".

Many coal-fired power stations are burning less coal because of wind farms. In South Australia, for example, wind farms now produce 26% of the electricity and, while coal-fired stations used to produce 42%, they now only produce 25% of the state's electricity. Over the six years this has been happening, greenhouse gas emissions from power generation has been decreasing.

The main reason that coal-fired power stations have stayed in service for so long is that the power consumption in Australia, until recently, increased faster than wind farms were being built. Consider, for example, how popular big plasma TV sets are; they can consume as much power as a refrigerator. Air conditioning too, is a big electricity consumer, and is becoming more common, at least partly driven by rising temperatures due to climate change (which, of course, is driven largely by burning fossil fuels).

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Wind farms result in less CO2 being released into the atmosphere than would be the case if they were replaced by fossil fuel power generators.

Also see Do wind farms really save carbon dioxide emissions?



How much electricity do wind farms generate?

 
Wind energy contribution to total SA power generation to mid-2012
Wind farm generation
Figure from the Australian Energy Market Operator (AEMO) 2012 SA Supply and Demand Outlook report
A common criticism of wind farms is that they don't really generate a significant amount of electricity.

In fact the typical utility-scale wind turbine seen in Australia today has the capacity to generate up to about two megawatts, and on average will generate about 35% of that (see capacity factor, on another page). The capacity factors achieved in a number of South Australian wind farms is shown on another page.

The graph, from the Australian Energy Market Operator (AEMO) 2011 draft 2011 SA Supply and Demand Outlook report, shows that 20% of SA's electricity came from wind farms in 2010/11. Note also on the graph wind energy is growing quickly. The same report stated that SA's greenhouse gasses due to electricity generation decreased by about 20% over the same period.

Andrew Miskelly provides daily wind farm output in a graphical format in wind farm performance.

Many of the wind farmers, when announcing a new wind farm, will make a statement about how many homes it will be able to supply with electricity. I have listed some of the numbers used by various companies elsewhere on this site; they vary from 400 to 740 homes supplied per installed megawatt of wind power. These figures seem to assume that the average household electrical consumption is between 470 and 875 Watts; 470 Watts seems to me a little on the low side to be credible. Still, given that an Australian wind farm with an installed capacity of 50 MW would be only moderate in size, even if the average household consumption is 1 kW we can calculate that this moderate-sized wind farm would generate enough electricity to supply more than 17 000 homes.

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Also see Does wind power replace coal-fired power?, Power generation of wind farm which gives the actual amount of power generated by a number of wind farms and How does wind power compare to roof-top solar?.



 
Updated 2012/01/18

How does wind power compare to roof-top solar?

 
Working
PV: 2.043kW × 24 × 365 × 0.18 = 3 221 kWh/yr = 3.221 MWh/yr
Wind turbine: 2.1MW × 24 × 365 × 0.34 = 6 254 MWh/yr
Note: the 0.18 (18%) capacity factor for solar was derived from various sources including my own solar power installation and Wikipedia. The 0.34 capacity factor for wind was calculated as the weighted average of all the larger wind farms on the south-eastern Australian power grid.
Interestingly, while many claims are made that wind turbines do not generate much electricity, see elsewhere, the same claim is rarely made about roof-top solar power. (I am strongly in favour of roof-top solar power, but include this to show how unsupportable is this argument against wind power.)

The average roof-top solar power system in Australia is 2.043 kilowatts (Office of the Renewable Energy Regulator) and will generate about 3.2 megawatt-hours of electricity each year. A typical 2.1 megawatt wind turbine will generate about 6300 megawatt-hours each year, as much as around 2000 roof-top solar power systems!

The working for these calculations is shown on the right. See the glossary for an explanation of capacity factor and note that the capacity factor for Australian wind power is about twice that for Australian solar PV.

So, while putting a solar power systems on your roof is a step in the right direction in the fight against climate change, providing support to a wind-power company that wants to build wind turbines would be a much bigger step.

It is worth noting that the total solar PV installed in 2011 exceeded the total wind power installed in the same year – although, because of the lower capacity factor of solar, the power generated from this installed wind power will still be considerably greater than from the installed solar PV.



In what range of wind speeds do turbines operate?

It has been claimed that most of the time the wind is either too weak to run a turbine or it is so strong that the turbine has to be shut down. The fact is that turbines generate electricity about 70-80% of the time and the average capacity factor for Australian wind farms is around 35%. This indicates that they generate about 35% as much power as they would if they were operating at full capacity all the time.

 
Power curve of a Suzlon S88, 2.1 MW turbine
Power curve
Data from Suzlon
There is a wind speed below which a turbine will not rotate and will not generate any electricity; this is the cut-in wind speed. (Up to a wind speed of about 4m/sec. in the graph on the right.)

As the wind becomes stronger than this the turbine generates more and more power until the nominal (or full-power) wind speed is reached. (From 4m/sec. to 14m/sec. in the graph.)

As the wind increases above the nominal speed the turbine continues to generate its maximum power until the wind gets up to the cut-out (or stop wind speed). (From 14m/sec. to 25m/sec. in the graph.)

If the wind speed increases above the cut-out speed the blades are 'feathered' (turned about their axes so as not to produce rotational force at the hub) and the turbine stops. (Above 25m/sec. in the graph.) Winds of greater than 25m/sec. (90km/hr) are very rare in Australia.

Wind turbines generate power from the cut-in wind speed right up to the cut-out wind speed. A graph showing a one month generation record from a wind farm is above. It shows that most of the month that farm was generating some power. The graph was not chosen because it was in any way exceptional.

The amount of wind energy theoretically available is proportional to the cube of the wind speed.



Lightning strike

 
Lightning strike on a wind turbine at Hallett, South Australia
Lightning strikes turbine
Photo credit Helen Simpson, Osprey Photography
 
Sarah Zhang published a high-speed recording of ground-to-cloud lightning from wind turbines in Spain: Gizmodo, 2014/01/17.
Wind turbines are tall and they are often built on the tops of ridges; consequently they are often struck by lightning.

 
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The turbine in the photograph is at Hallett in Mid North South Australia. There was no damage to the turbine; there rarely is. There probably were a number of other strikes on Hallett turbines on the same night.

On 2012/03/21 a wind turbine at Wonthaggi Wind Farm in western Gippsland, Victoria, was damaged by lightning, apparently resulting in a blade being broken. (ABC on-line news) This is the only serious turbine damage due to lightning strike that I have heard of in Australia where there are over a thousand operating utility scale turbines (as of mid 2012).

Less fires started by lightning?

Interestingly, while a lightning strike on a grassy or treed hill-top might well start a fire, if that hill is protected by a row of turbines the fire risk would be greatly reduced. Instead of being able to start a fire by striking the ground the lightning that strikes a wind turbine will be conducted safely to the earth.

In an electrical storm wind turbines will be hit by lightning just as communication towers and power transmission pylons have been struck by lightning for decades. Fires are rarely (if ever) started following a lightning strike on a communication tower or power pylon; similarly there is no reason to believe that a fire will be started by a lightning strike on a wind turbine.

On 2012/11/28 a neighbour of mine told me that he had seen multiple lightning strikes on the turbines of the Snowtown Wind Farm during a thunder storm a few days earlier; result – no fires. I have also received a record of twenty lightning strikes on a South Australian wind farm; result – no fires.

It may be claimed that wind turbines attract lightning. This is true to some extent; lightning will tend to strike anything that sticks up higher than anything else in the vicinity – hence the advice of not standing in an open field in a thunder storm. It is conceivable that the presence of wind turbines will very slightly increase the number of lightning strikes (because a slightly lower voltage build-up will be required to produce a strike over the slightly shorter distance from cloud to ground). But, so long as the towers stop the lightning strikes from causing a fire, what harm is there in this?



Aesthetics

This is probably the most subjective of all the points of contention regarding wind farms; some people like the look of a line of wind turbines turning lazily along a distant ridge, others think them a blot on the landscape.

Interestingly, I don't think anyone likes the look of a line of power pylons. Wind farm construction requires the construction of a transmission line to take the power from the wind farm to the nearest point at which it can be fed into the main power grid.

If wind turbines are not built, other forms of power generation will have to be built. Is a fossil-fuelled or nuclear power station more aesthetically pleasing than a row of wind turbines?

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Roads have to be built to give access to the turbines for construction and maintenance. An old curving country road, especially if it is lined with trees, can be attractive, a new road very rarely is.

Trees and other native vegetation have been removed from some ridges to allow the building of turbines and the access roads. At one time many Australians would have thought the removal of trees from land a step forward and an improvement, but I think that time is long past; most Australians now would prefer that trees be left in place.



 
Altered 2013/12/26

Confidentiality (and 'gag clauses')

 

Bad behaviour from at least one company

Senator Chris Back made a speach in Federal Parliament on 2012/10/30 in which he quoted from a WindLab contract. There can be no doubt that this particular contract, in which the landowner was expected to sign away his right to complain about noise, was unethical.

I inquired into the matter with WindLab and was told that the clause was in an old contract that they no longer use. At 2012/11/02 WindLab and Repower were preparing a statement.

Behaviour such as this from a wind power company is deplorable and gives the whole industry a bad reputation.

Trust Power have also proposed an agreement with non-turbine-hosing neighbours for the Palmer Wind Farm that involves a gag clause (December 2013).

Common-law rights

So far as I understand, no-one can sign away their common-law rights. However, people who do sign contracts in which they agree to not complain about noise nusiance may well believe that they have lost this right.
The confidentiality clauses that wind farm developers put in their contracts are used by the anti-wind power lobby to claim that farmers who have wind turbines on their properties are 'gagged' and cannot complain if they subsequently become ill or have problems with noise.

I used to believe that this was simply a fabrication, or at least an exaggeration, of the wind power opponent groups, but unfortunetly some companies have attempted to do this (see the box on the right).

Wind farm companies have to come to agreements with land-owners about the use of land for the wind farm turbines. If any particular land-owner knew what the other land-owners were being offered then he would have an advantage in his negotiations with the wind farmers. Similarly, if a wind farm company has to buy-out the house of someone who has a problem with turbine noise, they do not want the details of the deal known to everyone. They may have to buy-out someone else later on, and knowing the details of any previous buy-out would give the person selling an advantage.

Any secrecy is undesirable in these sort of cases because secrecy leads to mistrust and suspicion. Any secrecy can also be used by wind farm opponents to cast suspicion on the motives of wind farm developers; with some justification.

Unfortunately it is normal business practice to try to minimise costs, so the wind farmers make their agreements with land-holders confidential. In real life, farmers quite probably will talk to their neighbours about how much they have been offered to host wind turbines; so it is questionable what confidentiality agreements achieve.

If the wind farmers hope to win the trust of the communities in which they are intending to develop their projects, they should minimise secrecy. Everyone knows that there is some secrecy/confidentiality, but by its very nature, no-one can know how much there is. Secrecy often leads to mistrust.



 
This section written 2011/03/12

Self-inflicted problems

Some problems complained about seem mainly to be self-inflicted. One of the submissions written to the Australian Senate inquiry into the "The Social and Economical Impact of Rural Windfarms" (Australia, 2011) was from a couple who refused to allow the wind farm developers to build turbines on their land (near Oaklands Hill Wind Farm in SW Victoria).

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They complained of friction with neighbours who had signed such agreements and of their costs, time and trouble opposing the wind farm proposal. They complained of the (anticipated) reduction in the value of their land and of receiving no benefit from the wind farm.

Had they agreed to have the turbines on their land then there would be no cause for friction with their neighbours who also had turbines, they would not have incurred any costs in opposing the development, their land value would have increased because of the increased income it generated, and they would have benefited from the development.



 
Updated 2011/05/03

Denmark and wind power

In proportion to the number of people in the country (ie. per-capita) Denmark has more wind power than any other country in the world. It also produces a greater percentage of its power by wind than any other country, and has a greater amount of wind power per dollar of gross national product. It is, therefore, often a target for nonsense stories from wind power detractors.

Wind farm opponents have said that Denmark is shutting-down wind farms because they don't work; this is quite false, Denmark continues to build more wind farms (many off the coast because of limited available land space – it is a densely populated country).

Denmark routinely produces more than 20% of its electricity from wind and has generated over 30% in a few months. There are plans to increase the share of wind power in Denmark up to 40%. It does power-share with Norway, a nearby country that has a lot of hydro-power.

In May of 2011 I was told that Denmark is to stop building wind turbines onshore and will only build offshore in future. I had an email from Karina Lindvig of the Danish Wind Energy Association stating that "there is absolutely no truth to that story".

A survey of over 16 000 Europeans by Eurobarometer conducted from February to April of 2002 found that "Denmark, Netherlands and Sweden place the most faith in renewables".



 
Added 2011/05/29

Too many turbines

I am sure that some people think that there are just too many wind turbines in a particular area or too many all together.

I would suggest that this in not a fault of the turbines or those who build the turbines, but an indictment of our greed for cheap and plentiful energy. So long as we want more and more energy it has to come from somewhere, and wind turbines are less damaging than most of the alternatives.



 
Altered 2014/02/06

Wind farms have high approval in the general community, but are less popular locally:
NIMBYism

 
Why oppose wind power?
Why not wind power?
Of course this is an oversimplification, but in my experience it is the main reason for most of the opposition to wind farms. How many wind farm opponents look at the bigger picture and consider the damage that will be done to the planet and to the lives of generations to come?
 

NIMBYism in balance

It is natural and right to care for what is 'in our backyard'. It is the ethical question of 'when should I overlook a small harm to myself for the sake of other considerations?' that needs to be answered fairly.

A single 2MW wind turbine in Australia will abate between 3000 and 6000 tonnes of carbon dioxide each year. The Garnaut report showed that Australia's CO2 emissions were 28 tonnes per person in 2006. So one wind turbine will generate enough electricity to abate the emissions of some one to two hundred Australians.

The question that must be asked is 'how much harm is this turbine going to do me, compared to the good it will do for the planet?'

Both in Australia and overseas, wind turbines, as a way of generating electricity, have a high level of approval (see opinion surveys on community attitudes to wind farms – showing high support for wind power in Australia).

But actually propose building a wind turbine within two or three kilometres of someone's house and the likelihood of opposition increases greatly. The obvious conclusion is that this is simply NIMBYism (Not In My Back Yard). While there is a lot of truth in that, it's not the whole story.

There are a number of reasons why people might oppose wind farms. One is that some feel a wind farm is an unwarranted invasion and spoiling of the place that is their home and environment. Some people just don't like the look of wind turbines and don't want to have to see them every time they go outside. Many don't make a judgement based on ethical reasons; don't weigh-up the total good against the total bad. They are willing to forget about the global need to reduce greenhouse gas production (it is a problem that is invisible and largely in the future) and oppose the more immediate perceived 'blight on their landscape'. Unfortunately, in the case of wind power developments, many people listen to the abundent and varied lies spread by those who hate wind turbines, and are swayed by them; while if they knew the facts, they would feel differently.

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Farmers who are to have turbines built on their land, and receive lease payments for the use of that land (several thousand dollars per turbine per year) are, understandably, generally strongly in favour. A householder who is going to have several turbines built a few kilometres from his or her house and get little direct financial benefit is usually, equally understandably, less enthusiastic.

It is becoming clear that, if local opposition to wind power is not to overwhelm general approval, there needs to be more reward for those people who host turbines in their vicinity, but do not currently receive any income from them. How this might be done, beyond the Community funding that often comes with wind farms, is not an easy question to answer.

And who should pay for it? Wind farms benefit the whole population by increasing the amount of renewable energy available; so should some compensation be paid out of taxation revenues? It would seem simpler and preferable if it were left to the wind farm operators, but care must be taken to not kill the goose that lays the golden egg.



Turbines at sunrise
Turbines at sunrise
The first photo I took in the morning after sleeping the night in a swag behind the car on the left.
North Brown Hill Wind Farm


 
Added 2011/06/22

Safety

 
Energy generation methods - safety
Graph credit UK Centre for Sustainable Energy
The UK Centre for Sustainable Energy published a document Common concerns about wind power that included the following:
"Taking figures from the start of the commercial wind energy industry in 1975 up to 2010, there have been 44 recorded fatalities (this includes a technician who reportedly committed suicide by hanging), an average of 0.054 deaths/GWey. Conventional fossil fuel industries have considerably higher rates, ranging from 0.197/GWey for natural gas, to 6.921/GWey for coal and 15.058/GWey for liquefied petroleum gas. The outlier is nuclear energy, with just 0.048 deaths/GWey due to accidents – although it should be remembered that the hazards associated with nuclear energy are much greater in the event that something goes wrong, with 'latent mortality' difficult to quantify."
*GWey is an abbreviation for Gigawatt-energy-years, so the fatalities are related to the amount of energy produced in order to allow a comparison of safety in the various power generation industries.
 
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Altered 2014/06/10

Wind farms are not the cause of rising electricity prices

Wind farm opponents often point to increasing electricity prices and claim that renewable energy, and wind power in particular, is to blame. The facts are otherwise. (Costs of wind power are discussed elsewhere.)

 

Wholesale electricity prices have been falling

The Australian Energy Market Operator average price tables show that the wholesale prices of electricity have been falling in the interconnected eastern states from 2006/07 to 2011/12. Most of Australia's wind farms were brought online during this period. Also see The Conversation: Electricity prices fall: renewable energy deserves merit.
 

Renewables are suppressing electricity prices

 
The USA experience
Wind energy share
The 11 US states that get more than 7% of their electricity from wind energy have seen their electric prices decrease by 0.37% over the past five years, in contrast to all other states, where electricity prices have increased 7.79% during that time.
From Climate Crocks
On 11th July 2013 Sid Maher had an article in The Australian titled "Electricity market shrinks by 40pc as prices tumble".

Mr Maher discussed the increased supply of renewable energy to the market. He quoted the Chief Executive of the Energy Supply Association of Australia (ESAA), Matthew Warren, as saying "One of the major effects of this increased supply of renewable energy in a shrinking national market is to suppress the wholesale price of electricity." Note, the generation of power from renewables, including wind, is suppressing wholesale power prices.

Dylan McConnell, Research Fellow, Melbourne Energy Institute at University of Melbourne wrote an article for The Conversation titled "Power of the wind – how renewables are lowering SA electricity bills".

The article discusses a proposal by The Essential Service Commission of South Australian (ESCOSA), to lower electricity prices, 'by an average of $160 per household'; and ascribes the lower costs to the 'Merit Order Effect' of SA's plentiful renewables.

 

International Energy Agency forcast that renewables will surpass gas by 2016

"As their costs continue to fall, renewable power sources are increasingly standing on their own merits versus new fossil-fuel generation," said IEA Executive Director Maria van der Hoeven (2013/06/26).
 

Australia has relatively low retail electricity prices

Opponents of renewable energy have falsely claimed that electricity prices in Australia are high because of wind and solar power. Quoting from page 40 of the report "Energy in Australia, 2012" from the Bureau of Resources and Energy Economics:
"Households in Australia face relatively low retail electricity prices compared with many OECD economies. Although Australian electricity prices were above those in some countries such as the United States and Canada, they were just below the OECD average in 2010."
Of course retail prices have risen significantly in Australia since 2010, but have they also risen significantly in other countries?
 

Cost of renewables to the consumer

On 2013/06/29 the Clean Energy Regulator gave the volume weighted average market price for large-scale generation certificates (LGC) as $38.69/MWh. What this means is that, on top of whatever price the wind farmers can get for the electricity they generate on the open market, they get another $38.69 per megawatt-hour because the power is renewable. $38.69/MWh equals $0.03869/kWh – about 4¢/kWh. This is factored into the retail price of electricity. So if a quarter of the electricity is renewable, as in South Australia, about 1¢ is added to the approximately 25¢ that one pays for electricity; a 4% increase due to wind farms.
The Australian Energy Market Commission's report on "Future Possible Retail Electricity Movements: 1 July 2010 to 30 June 2013" stated in its Executive Summary that "the most significant driver of the expected increase in residential electricity prices is the increasing cost of distribution services, which is expected to contribute 41% of the total increase in residential electricity prices". Other substantial increases were ascribed to wholesaling (19%), transmission (8%) and retailing (14%).

On the other hand:

"Renewable Energy Target (RET) costs are forecast to comprise around 11% of the total increase in residential electricity prices at a national level. This increase in costs is related to an expansion in the renewable energy generation target from the Mandatory Renewable Energy Target of 9,500 GWh to the RET of 45,000 GWh by 2020. Other components of the residential electricity price include feed in tariff scheme costs and the costs of other state based energy efficiency and demand management schemes. Together these cost components comprise around 5% of residential electricity prices at a national level and are not expected to have a significant impact on the total residential electricity price over the reporting period in most jurisdictions."
The report also gives 3% as the "contribution to national price increases" from the Renewable Energy Target.

PJM, the independent grid operator for all or parts of 13 US states produced a report that confirmed that wind energy is decreasing both the price of electricity and emissions of harmful pollutants. (See Into The Wind.)

Opponents of renewable energy (including the Liberal party) like to connect the proposed carbon tax with a rise in electricity prices. Energy prices are rising world-wide; and will continue to do so. The cheap sources of petroleum have been used up, those that remain cost more to exploit. Until recently consumption of electricity has risen steadily (in Australia and world-wide), this has led to a need from the building of expensive new electricity transmission and distribution infrastructure. Domestic solar power has helped to decrease the average demand for power from the electricity grid, but peak power consumption, so far as I know, has not declined, and the generation and transmission system has to be able to cover peak demand. Ultimately this must all be paid for by the end consumers of the electricity.

There is no justification for the claim that power prices would fall without a carbon tax.

Renew Economy has an informative article on the relationship of wind power to electricity costs in South Australia, dated 2012/03/21.

Heat wave of January 2014

Giles Parkinson on RenewEconomy pointed out that solar and wind power forced wholesale electricity prices down. He quoted a report by Sinclair Knight Merz:
"We conclude that wind generation is likely to have significantly reduced the price impact brought about by sharply rising demand during the heat wave period. In the seven days to 19 January, wind farms contributed around 6 per cent of overall supply in SA and VIC, and as a consequence, wholesale prices were at least 40% lower (on a consumption weighted average basis) than they would have been without the contribution of wind."

ACT has the highest renewables target and lowest electricity prices

Sophie Vorrath, writing for RenewEconomy says that the proposed development of up to 550MW of wind, solar and waste to energy projects, working toward their 90% renewables target (by far the highest on the mainland), will help them retain the lowest electricity prices of any state or territory in Australia.
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This section added 2012/01/29

Earthquakes and wind turbines

No wind turbines damaged in major 2011 Tohoku Japanese earthquake

Kelly Rigg wrote the following in the Huffington Post on 2011/03/17.
"Colleagues and I have been directly corresponding with Yoshinori Ueda leader of the International Committee of the Japan Wind Power Association & Japan Wind Energy Association, and according to Ueda there has been no wind facility damage reported by any association members, from either the earthquake or the tsunami. Even the Kamisu semi-offshore wind farm, located about 300km from the epicenter of the quake, survived. Its anti-earthquake "battle proof design" came through with flying colors."
The catastrophic failure of the Fukushima nuclear power station due to the tsunami caused by the earthquake is well known.

Also see the Wikipedia article.



The Moon and a turbine
Turbine and Moon
The Moon behind a turbine late in the day at North Brown Hill Wind farm


 
Edited 2014/0614

Are agriculture and wind farms compatible?

 
Turbines on agricultural land in Germany
Turbines and agriculture
Image credit: Earth-The Operator's Manual
 
Wind turbines and houses in the tulip fields of North Holland
Turbine and house
Photo credit Normann Szkop
Note how close the turbine is to the house
The original photograph can be seen on Flickr
 
Canal, turbines and houses
Photo credit Normann Szkop
Four houses and two turbines close together
The original photo can be seen on Flickr
The photos on the right show that wind turbines and agriculture can fit together very well. The top photos shows many turbines in agricultural land in Germany, the next two show turbines in highly productive tulip fields in The Netherlands.

One need only look at the US experience to see that agriculture and wind power are very compatible. The top three US states by value of agricultural production are also the top three states by installed wind power.

StateAgricultural production $mInstalled wind power MW
California31 8355 549
Texas16 49812 212
Iowa14 6535 137

The figures for agricultural production above were obtained from Stuff about states, dated 2004 (I was unable to find more recent data), and the figures for wind power were from Wikipedia, dated the end of 2012.

 
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Iowa is in the heart of the US Corn Belt and is sometime called, at least in the United States, the "Food Capital of the World". It has the highest concentration of wind power, in terms of Watts per unit area, of any US state. In 2012, 24.5% of Iowa's electricity was generated by wind power.

Another section of this page deals with the relationship between wind turbines and aerial agriculture.



 
Altered 2014/02/15

Light aircraft, agriculture and wind turbines

Aerial spraying of a cereal crop in Mid North South Australia
Crop spraying
Note that the plane is very low and the pilot would have to be aware of any power lines in the vicinity.

In this section...

Aerial Agriculture Association of Australia
UK Civil Aircraft Authority
Mt Emerald aeronautical assessment
Repower agricultural flying study
Light aircraft and turbulence
 
Concern has been expressed about restrictions on the use of aircraft for spraying, seeding, fertiliser and mouse-bait application in the vicinity of wind turbines. (Operation of aircraft for fire fighting is dealt with elsewhere.)

 

Agricultural Aviation Expert Witness Report

Union Fenosa Australia commissioned an Agriculture Aviation Expert Witness Report from Barry Foster in relation to their proposed Berrybank Wind Farm. If I was to summarise what Mr Foster said in a few words, it would be that the presence of wind turbines lead to some inefficiencies, but no danger, to aerial agriculture aircraft. Mr Foster wrote of a 500m buffer zone required for aircraft operations around wind turbines.

Places where wind turbines and agriculture successfully coexist

Much of the land of South Australia's Yorke Peninsula Wattle Point Wind Farm is used for cropping, the 111 turbines of Collgar Wind Farm are in the Western Australian Wheat Belt. The three top US states by value of agricultural production are also the three top states by installed wind power (see more here).

References

Civil Aviation Safety Authority of Australia's (CASA) document Man Made Obstacles Located Away From Aerodromes, foi-ef12-8748.pdf, 2009, deals with aerial agriculture starting with point 116, but seem to give no specific guidelines.

UK Civil Aviation Authority Policy and Guidlines on Wind Turbines, 2012. Does not discuse aerial agriculture.

Collision between aircraft and turbines is an obvious risk, although so far as I have been able to discover, at most there have only been two aircraft that have ever collided with wind turbines. (For one of these see CASA Flight Safety magazine, Nov.-Dec. 2011; article by Keith Tonkin and Gabby O'Brien. CASA is Civil Aviation Safety Authority [of Australia].) The same article ascribed two other aircraft fatalities to wind turbines;

  1. "Fatal loss of control of [an] aircraft while manoeuvring around wind turbines;"
  2. "Fatal flipping of an idling helecopter due to excessive tailwind gust."
No further detail was given on these incidents, so it would seem likely that they were connected with turbulence from the wind turbines. The article also mentioned a power line strike, presumably in a wind farm, and four collisions with wind monitoring towers.

On 2014/02/06 I contacted CASA Aviation Projects asking for more information on the aircraft accidents. They were unable to provide any more information on the claims, nor contact details for the authors, so some doubt about the veracity of the claims exists.

On 2014/04/28 it was reported that a light plane crashed "into a wind farm" in South Dakota, USA. The weather was foggy at the time. The reason the plane was flying so low was not reported. (In Australia at least, it is illegal to fly so low except in special circumstances.)

At the end of 2012 there was 274GW of installed wind capacity world-wide; probably around 200 000 utility scale turbines and roughly the equivalent, in capacity, of about 100 000 modern turbines. Wind turbines would be easily avoided as they are large and conspicuous.

Power lines, especially the thin wires used for supplying rural homes, stretched between poles that may be 500m apart, are a major hazard. Collision with power lines do happen, and the construction of wind farms involves building more power lines.

Interestingly, UTube has video clips of crop dusting planes flying within a few metres of wind turbines, see here and here.

This is my own opinion; a pilot who can avoid power lines that are almost invisible except within a hundred metres or so should have no difficulty at all in avoiding something as huge and obvious as a wind turbine.

Aerial spraying should be done in calm conditions because of potential spay-drift; in calm conditions the turbines will be still. They typically do not start generating electricity until the wind speed reaches four metres per second, so during spaying operations there will not be any turbulence created by the turbines to bother the aircraft. I have been told that some aerial agricultural operations, such as mouse baiting and the application of fertiliser, are best done from altitudes higher than wind turbines.

I have been informed that it is standard procedure for any farmer who agrees to have wind turbines on his property to also agree to not use aerial agricultural methods – for insurance reasons. If this is so, then the loss of business to aerial agricultural operators would explain why they seem to be opposed to wind farm development.

Turbine turbulence can impact on aircraft safety; there is a section on this below, and it is also discussed in the Mt Emerald assessment.
 
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Aerial Agriculture Association of Australia

The Aerial Agriculture Association of Australia (AAAA) has policies on "Fire Fighting" and "Windfarms". (As of 2012/10/04 the Fire Fighting policy document did not mention "turbine", "windfarm" or "wind farm".)

 

Collisions

While there are around 200 000 utility scale turbines in the world, so far as I have been able to find out there have only been two aircraft accidents world wide due to either collision with a turbine or the turbulence created by turbines.

Meteorological towers

David Jack Kenny of the US Aircraft Owners and Pilots Association (AOPA) stated (as of 2012/03/04) that there had been at least three pilots killed in collisions with unmarked meteorological towers in eight years.

Discussion of turbine hazard

Another page of the AOPA, by Ian J. Twombly, discussed wind turbines as a potential hazard to pilots. Interestingly, it did not mention turbulence.
The AAAA Windfarm policy document talks about the duty of care of the "regulators, asset developers and operators of the need for action on their part to fulfill their duty of care to Australia's aerial applicators". The document goes on to discuss safety and economic impact concerns. In regard to safety it is significant that there seems to have never been any collisions between aircraft and wind turbines (see the box on the right); however, in light of the recorded accidents involving collisions with meteorological masts and their supporting wires the AAAA's demand of better marking of these hazards seems well justified.

The AAAA make the point that the presence of wind turbines on land affects, not only the operation of aircraft on that land, but also on nearby land. While the owners of the land with the turbines are financially advantaged by the wind farmers, neither the owners of the nearby land nor the aerial operators receive any compensation for any economic harm done to them.

From my reading of the AAAA document the main concern is the economic impact that wind farms have on the 'aerial application' industry. The document does not include the word 'turbulence'.

UK Civil Aircraft Authority

The Directorate of Airspace Policy of the UK Civil Aircraft Authority (CAA) produced a guidelines document on wind turbines. While the document did not give anything definitive on turbulence, it did say:
"There is evidence of considerable research activity on modelling and studying the wake characteristics within wind developments, using computational fluid dynamics techniques, wind tunnel tests and on site lidar measurements. A thorough literature survey would be necessary to establish the scale and the advances of the research findings."
and:
"... the CAA has received anecdotal reports of aircraft encounters with wind turbine wakes representing a wide variety of views as to the significance of the turbulence. Although research on wind turbine wakes has been carried out, the effects of these wakes on aircraft are not yet known. Furthermore, the CAA is not aware of any formal flight trials to investigate wake effects behind operating wind turbines."

I have not been able to find much credible information on this matter. I'd be pleased to hear from anyone who knows of any. On 2012/02/01 I emailed the Civil Air Safety Authority of Australia (CASA) inquiring about light aircraft and wind turbines. I had received no reply by 2012/02/18.

Mt Emerald Wind Farm aeronautical assessment

This report was done for Transfield by Rehbein Airport Consulting.

Relevant to this subject the report states:

"A wake length equivalent to 6 times the rotor diameter is considered a minimum in wind conditions of 10-15 knots [18-28 km/h or 5.1-7.7m/sec]. When the wind turbines are operating in winds of 15 knots [28 km/h or 7.7m/sec] or greater the wake from a single turbine is still prevalent at 10 blade diameters and can persist for up to 16 blade diameters downwind of the turbine. The majority of modern wind turbines reach their maximum output, and in theory, generate the strongest wake turbulence in wind speeds of approximately 47km/h [25 knots or 13m/sec]. At this speed, and in combination with the wake produced by other turbines, the wake may exist up to 5km downstream from a large turbine cluster of several rows.

Agricultural aerial spreading and spraying operations are normally conducted at very low levels and often require calm or very light wind conditions of less than 8 knots (15km/h, 4.1m/sec). At these wind speeds it is reasonable to assume the wake can extend for a distance of 6 rotor diameters or 600m downwind of the nearest turbine based on the proposed rotor diameter of approximately 100m. Given the distances from wind turbines to cultivated areas of land on adjacent properties outside the wind farm boundary there should be minimal impact on agricultural aerial operations."

Repower study in relation to the Ceres Project on Yorke Peninsula, SA

I had the following from Peter Sgardelis of Repower on 2012/03/05:
"Unlike most of the mid-north, the Yorke Peninsula is relatively flat and predominately farmed densely for wheat, barley and legumes. Due to these farming practices it has been argued that aerial spraying may not be possible for neighbours of the wind farm if wind turbines are installed. At the moment we are attacking this issue via a 4 tier study;
  1. Commissioned a solutions based 3rd party report by an Aerial specialist to quantify the issue in terms of how close planes can fly, turn etc. etc.
  2. Asked for public submissions from the community that believe they will be impacted by the wind farm.
  3. Commissioned a report to quantify the cost differential between aerial and tractor based spraying.
  4. Surveyed our participating landowners and their neighbours.
At this stage we are probably 50% through our studies and are not able to release our results, suffice to say that we are confident we will not impact the farming integrity of YP land. There are no definitive studies in this area in Australia or even globally and generally it becomes a specific community issue."
The Ceres Project is a very large proposed wind farm with undersea cable connecting to Adelaide.

Light aircraft and wind turbine turbulence

The Australian Department of Infrastructure released a revised document titled " Managing the risk to aviation safety of wind turbine installations (wind farms)/wind monitoring towers" on 2012/07/15.

I quote the section of this document that dealt with turbulence in full:

"Wind farm operators should be aware that wind turbines may create turbulence which noticeable up to 16 rotor diameters from the turbine. In the case of one of the larger wind turbines with a diameter of 125 metres, turbulence may be present two kilometres downstream. At this time, the effect of this level of turbulence on aircraft in the vicinity is not known with certainty. However, wind farm operators should be conscious of their duty of care to communicate this risk to aviation operators in the vicinity of the wind farm. CASA will also raise awareness of this risk with representatives of aerial agriculture, sport aviation and general aviation."
Note that the document states "turbulence which [is] noticeable" and "turbulence may be present two kilometres downstream". There is no suggestion that this level of turbulence is dangerous to aircraft.

Aerial spraying of insecticide and herbicide can only be safely done when there is little or no wind. At other times the spray will drift off-target. When there is little or no wind, wind turbines will not be operating and so will not create turbulence. It should also be remembered that many things create turbulence in the wind; trees, hills and coastal cliffs are common examples, even convection on a warm day can cause turbulence.

So far as I have been able to discover, no aircraft, anywhere in the world, has ever crashed into a wind turbine or due to turbulence from a wind turbine or wind farm.

Hearsay

I have been told of a helicopter pilot who made a point of flying backward and forward on the downwind side of a South Australian wind farm. He may not want to be identified so I will not give information on the helicopter or wind farm involved. I was told that he was wanting to test whether the turbulence would have any effect on his aircraft; and found no noticeable effect at all.
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This section added 2012/02/13


Pressure in the ears

 
Camp at wind farm
Camping under wind turbine at Waterloo Wind Farm
A woman told me that her husband and she went within about four kilometres of some turbines (at Waterloo Wind Farm) and found that they had 'pressure in their ears' that they could not account for by changes in altitude. She went on to say that it was about a day before her ears came back to normal.

There are several reasons I cannot believe that the problem she had had anything to do with the turbines. One reason is this: I slept under those same turbines on the night of 2012/02/09 (my swag is visible behind the car in the photo on the right). (The turbines were operating all night, at varying speeds.)

I noticed no pressure changes in my ears at all – indeed, I had a perfectly good night's sleep.

She was 4000m from the turbines, I was maybe 80m (right underneath). So she was 50 times as far away as I was. Using the inverse square law of physics, that would indicate that any sound (sound is vibrations in air pressure) from a single turbine where she was would be 50 x 50 = 2500 times weaker than where I was. (An adjustment would need to be made because she was probably roughly equally distant to a number of turbines. But even allowing for this the sound intensity where I was would be hundreds of times higher than where she was.)



 
This section added 2012/02/13


Feeling of place (or personal space)

Many people, probably most people, who have lived in an area for a long time, develop a feeling of attachment or some sort of ownership toward that place.

Wind farms, and sustainable energy in general, are necessary if the world is to limit climate change. Some people, perhaps those who tend to look at 'the bigger picture' or 'the greater good' will see a proposed sustainable energy development as being desirable and a cause for pride in their area.

On the other hand, many people will see a wind farm as an intrusion into their neighbourhood. If they do not see wind power as desirable and necessary they might be offended and believe it to be an imposition that is being pushed onto them by big business or government. This is related to NIMBYism, but is not entirely that. These people quite probably feel protective toward their immediate vicinity. Some of them will have worked to improve their locality in some sort of voluntary capacity.

The only answer to this problem (I consider it to be a problem, others may not do so) would seem to be to try to make people understand how disastrous unmitigated climate change will be and therefore to see the urgent need for the development of sustainable energy.

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Can wind turbines be louder at a distance than up close?

Ms Laurie and others have tried to explain how illness may be caused by wind turbines by claiming that wind turbine sound can be louder at a distance than it is close to the turbine. Ms Laurie has been reported as saying "You can stand underneath the turbines and not hear a thing, but up to five kilometres away they can sound like a jet engine or a low rumble or a washing machine." This is absurd. If a turbine is operating you will hear it when you are up close, but it is very unlikely that you will hear any wind turbine under any circumstances at a distance of five kilometres. This statement suggests that Ms Laurie has taken very little trouble doing any personal investigation.

(I've studied wind power for years and visited most wind farms in SA, Victoria and WA; the greatest distance I've ever heard wind turbines from is 2.5 km and then they are barely audible in ideal listening conditions. See elsewhere. The dose-response principal of epidemiology is also relevant to this point.)

 
In addition to the reduction of sound levels with the inverse-square-law sound attenuates at about 5dBA per kilometre because of atmospheric absorption.
Sound moves outward from the source in all possible directions with the intensity becoming weaker with distance according to the inverse-square law (twice the distance, quarter the intensity; three times the distance, one ninth the intensity; etc.) In decibel terms, sound levels normally decrease by 6 dB with each doubling of the distance.

Apart from the laws of physics one simply needs to visit a wind farm to convince oneself that the 'louder at a distance' claim is nonsense. As you move from turbine to turbine it is always the nearer ones that you hear, you never hear those further away drowning out the nearer ones.

There are some special circumstances where sound might diminish by something less than the inverse-square of the distance, over a flat surface (such as water) and where there is a temperature inversion, for example, but still it always diminishes with distance. Hills and valleys could direct sound in some directions more than others, but this does not stop the sound diminishing with distance. And when a number of turbines are involved, while you double your distance from one, you might not be doubling your distance from others; the sound level you hear depends on all of the turbines and their distances.

Some sounds from turbines can be stronger in some directions than in others (from my own experience).

It is possible that once in a while pulses of sound coming from different turbines at regular intervals could arrive at a particular spot simultaneously and reinforce each other. Such pulses from two turbines would double the sound intensity at a point, that is increase it by about 3dB, from three turbines the sound would be increased by 4.7dB. Sounds from two turbines combining would happen occasionally, from three more rarely, and from more than three very rarely. See also noise and wind turbines.

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This section added 2012/06/18

Motivation of proponents and opponents

Unlike most of these pages this section is opinion and speculation. What motivates those who are in favour of wind farms and those who oppose wind farm developments?

 

Selfish or altruistic

It has to be said that those who favour wind power do so because it reduces greenhouse gas production and reduces deaths and serious illnesses due to coal-fired power plant air pollution. That is to say, their motivation is altruistic. Most who oppose wind power do so for selfish reasons.
Opponents are motivated by one or another of fear, dislike or hatred, envy, greed, ambition, selfishness or environmental concerns:

  • Fear may be from any of a number of sources:
    • Fear of being made ill by turbines (without any basis in fact);
    • Fear of being economically disadvantaged (again, often without factual basis);
    • Fear of having one's environment degraded;
  • Dislike or hatred, for whatever reason, of wind turbines;
    • Some people think that wind turbines are ugly (this is a matter of opinion and people's opinions differ) and that they will spoil the appearance of the area;
    • Those who are actively opposed seem to have feelings that go beyond simple dislike; dislike does not explain the lying that is so common in opponents' statements;
  • Envy of others around you who will be getting substantial income from a proposed wind farm while you feel you gain nothing;
  • Greed:
    • The greed of those in the fossil fuel industries who believe that growth in wind power will come at the cost of contraction in the fossil fuel industry and less profits;
    • The desire to force a wind farm company to buy an unwanted house at a higher-than-market price so that the owner can move to a more desirable, town, where home prices are higher;
  • Ambition in politicians who believe that it is to their advantage to look after the very wealthy fossil fuel industries;
  • Selfishness in those who feel that wind farms are well and good, just not nearby
  • While there are some genuine environmental concerns, those people who hold their concerns honestly will realise that wind farms are, at worst, usually the lesser of two evils. They are far better environmentally than unmitigated climate change.
Motivation of proponents can be selfish or altruistic:
  • Selfish:
    • Those who are investing in the wind farm are building an enterprise from which they hope to make a profit;
    • Landowners who will have turbines on their property will have a substantial increase in income;
    • Local business owners will make money from the oportunities available in construction and maintenance of the wind farm;
    • Local residents might be hoping to get a job from a proposed wind farm;
  • Altruism – in those supporters who want to see sustainable energy development in a world that is in desparate need of increased sustainability; others will want to see sustainable energy replacing fossil fuel energy because of the health problems that result from burning fossil fuels.
I have used derogatory terms like 'greed' and 'ambition' in those who oppose wind power development and less emotive terms such as 'building a profitable enterprise' in the case of proponents. The reader might consider this to be bias; I would hold that the former group are generally less ethical. Most people would agree that it is perfectly justifiable to want to establish a money making concern; while using underhand and dishonest methods to advantage your investments by discrediting the opposition is unethical.

Motivation is related to attitude and a person's attitude to wind power has a big affect on whether or not they are likely to believe they have been made sick by nearby wind turbines. I have discussed my motivation elsewhere.

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This section added 2012/05/05

Philosophy

It seems appropriate to write something on the philosophy of wind turbines and renewable energy in relation to our modern way of life and the alternatives: fossil-fuels or nuclear, or drastically cutting down on energy use. In what follows I will assume that the reader accepts the reality of anthropogenic climate change (ACC: the fact that the climate is changing and that it is Man's activities that are the primary driver for that changing). I have written about climate change on two other pages: the first deals with climate change in the international context, the second, in the Australian context. The science on ACC is settled.

I have dealt with the question of Why support wind power elsewhere, so will try not to repeat those points here.

In the simplest case we have two choices: business as usual, or tring to limit climate change and its speed of onset.

Ethics, moral philosophy, is about balancing our personal wants and needs against those of other people, and, I have argued, against the needs of all other life on Earth: the biosphere. Climate change modelling indicates that thousands or even millions of species are likely to become extinct and millions or even billions of people will be displaced if we do nothing; there will be terrible wars over land, water, and food. In any view of ethics such dire damage in the future would oblige taking serious action in the present to avoid or limit climate change, if such action is possible and can be achieved without huge costs.

That we can do something without huge costs has been shown by the South Australian experience: in early 2003 SA had no wind power, in 2011, 26% of South Australia's electricity was generated by wind power and over the same period the percentage of coal-fired electricity decreased from 42% to 25%. The financial cost has not been great, while the price of electricity in SA has increased, the increases are no greater than elsewhere and have been ascribed mainly to the costs of updating old infrastructure in the transmission system, rather than having anything to do with the cost of building and integrating wind power.

What costs and benefits have there been in developing the wind power in South Australia?

Environmental costs and benefits

There are environmental costs involved in developing wind power, a number of them are discussed on this page. However, the environmental costs of not developing renewable energy – letting climate change continue unabated – will be far greater.

Economic costs and benefits

It is difficult to be sure, but wind power is probably more expensive than electricity generated by burning fossil fuels (unless you add in the environmental costs of the fossil fuel option). (Fossil-fuel power is subsidised through subsidies given to the mining industry; the Australia Institute has estimated these subsidies at $4b per year.)

Of course SA cannot get by on wind power alone, the wind doesn't blow all the time, alternative power sources had to be retained. If much more wind power is developed, we will have to look at sustainable methods of generating electricity, including pumped hydro-power.

The wind farms have brought with them jobs for local people, business for local contractors, stores, hotels and other providers of accommodation. Many wind farms provide community development funds for the people in the vicinity.

Social costs and benefits

I live in Mid-North South Australia where there is a greater concentration of wind farms than anywhere else in Australia and where you might expect social costs to be at their highest. There are some people (estimated at a vocal half-dozen) in the vicinity of the Waterloo Wind Farm who are very vocal in their opposed to that development; there are several (perhaps another half-dozen) in the vicinity of the Hallett wind farms. Of course there are others who are less vocal elsewhere.

At least some of these people claim health problems due to the turbines; on another page I have explained at length that there is no acceptable evidence for more than annoyance and some sleep deprivation being directly due to wind turbines. There is certainly fear and anxiety in some people, but these are brought about by causes other than the turbines; the fear and anxiety can lead to some serious health problems.

Certainly some people feel that there are already enough wind turbines in the Mid-North; they would rather not see any more. This is a point of view based on aesthetic preferences.

One must then consider the social benefits. While some people don't like the look of wind turbines, others, like me, consider them graceful, elegant, and symbols of a more responsible future. Had the wind farms not been built more coal-fired power stations might have been, with consequent health problems that come with the toxins that they release into the atmosphere.

I hold, therefore, that the net social costs of wind power have been slight, and far outweighed by the benefits, especially if you consider slowing climate change as one of the benefits.



I have skimmed over the philosophical points above very lightly; I apologise for that. As for everything on these pages, I welcome reasoned comment, my email address in near the top of this page.
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Wind power problems, alleged problems and objections: links

Many other links are spread through this page; for example links relating to bird deaths and wind turbines are in the bird deaths section. Links relating to wind turbines and health are on my WindHealth page. General links relating to wind power are given on my Wind links page.
Recommended sources of information...

Mike Barnard has written an excellent summary of wind power myths and what the facts are.

The Australia Institute is an independent public policy research centre funded by grants from philanthropic trusts, memberships and commissioned research. It has a 134kB pdf document about The facts and fallacies of wind power.

Another useful document is "Wind Energy: The myths and the facts", from Sustainability Victoria, the full URL of the page is "http://www.sustainability.vic.gov.au/www/html/ 2148-wind-energy-myths-and-facts.asp".

The Clean Energy Council also provide fact sheets on wind farms, but they could hardly be called a disinterested party.

Paul Gipe wrote an excellent review of a book (the book was written in French, the review in English), edited by Vincent Boulanger and titled Wind Turbine Noise: Rumors, Gossip, Lies, and Stories. Obviously the fallacies about wind power are not confined to English-speaking countries.

Wikipedia has an extensive page on the Environmental effects of wind power.

An expert panel review of "Wind Turbine Sound and Health Effects" conducted for the American Wind Energy Association and the Canadian Wind Energy Association was available from the American Wind Energy Association (but the original link is no longer working).

 
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Feedback

Rational and informed arguments from anyone disagreeing with any of the points made on any of my pages are welcome. Do not expect me to change anything if you do not give convincing evidence in support of your arguments. My email address is near the top of all my pages.

Suggestions of additions are always welcome, compliments particularly so.

What constitutes valid evidence?

First, some examples of things that are not convincing evidence:
  • Anecdotes;
  • Postings on anti-wind sites such as Stop These Things which show a callous disregard for the truth;
  • Statements from groups set up to oppose specific wind farms such as Heartland Farmers, who are dishonest and do not give evidence in support of their claims.
  • Statements from disguised anti-wind power and anti-renewables lobby groups such as: the Waubra Foundation, Australian Landscape Guardians, Australian Environment Foundation and the Insitute of Public Affairs.
I could go on, but I'm sure that the reader will get the picture by now.

Some examples of valid evidence:

  • The NSW Farmers Guide to Wind Farms (what reason would they have for bias one way or the other?);
  • The study released by Professor Simon Chapman and discussed on The Conversation showing that health complaints from wind farms are very much related to scaremongers telling people that if they live near a wind turbine they should be sick;
  • The study by psychologist Fiona Crichton and others and published by the American Psychological Association a few days ago (see APA PsycNet) showing that people who are under the impression that they will become ill due to infrasound, and are then told that they are being subjected to infrasound, are likely to experience adverse symptoms;
  • The South Australian Environmental Protection Agency (EPA) report showing that infrasound levels near wind turbines was no higher than elsewhere; January 2013;
  • The evidence of my own eyes and ears;
  • More generally, material published in respectable peer-reviewed science journals.
If readers are interested in more of what I consider to be evidence they can get an impression by looking up a few of the hundreds of links on my Wind Links page.
 
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Index

On this page...
A good night's sleep at Waterloo
Abandoned homes at Waterloo?
Abatement intensity – table
Aboriginal sites
Absurdly inefficient
Access roads help fire-fighting
Aerial fire-fighting and wind turbines
Aesthetics
Agriculture and wind farms; are they compatible?
Agricultural Aviation Expert Witness Report
Air navigation lights
Annoying sounds
Are other countries abandoning wind power?
Barotrauma and bats
Barriers to animal movement
Bats killed by wind turbines
Bird deaths from wind turbines
Bird deaths at Waubra
Bird mortality - graph
Blade failure in wind turbines
Carbon intensity
CO2 and wind farms
CO2 released from wind-farm concrete
CO2 released per MWh - coal
Can a wind farm change the local climate?
Can wind farms affect rainfall?
Can wind farms affect temperatures?
Can wind power provide base-load
Can wind power provide peak-load
Carbon intensity – table
Compensation
Confidentiality
Conflict-my own experience
Cost of electricity
Cost of renewables to the consumer
Cut-in speed (of turbines) and bat deaths
Denmark and wind power
Do environmentalists oppose wind farms?
Do turbines frighten animals?
Do wind farms cause social conflict?
Do wind farms get government money?
Does wind replace coal?
Dr Cindy Hull on birds
Dubious fire claim
Earthquakes and wind turbines
Efficiency of wind turbines
Electricity generated must be consumed
Embodied energy in turbine tower
Emissions intensity – graph
Energy consumed in wind farm construction
Energy payback time for wind turbines
Envy
Erosion of sites
Factors, wind vs solar
Feeling of place
Feedback
Financial support for wind power in Australia
Fire hazard
Fire hazard without wind farms
Fragmentation of bird habitat
Fraud – speculation
General environmental concerns
Generally popular, locally opposed
Gradual variation when many wind farms
Groundwater and wind turbines
High temperature shut down
Honey bee problems?
How much electricity do wind farms generate?
How much power do wind turbines use?
How does wind power compare to roof-top solar?
How much CO2 does wind power save?
Hull, Dr Cindy, on birds
Inequible spread of financial benefit
Infrasound: low frequency noise
Infrasound: Geoff Leventhal
Infrasound: Peter Seligman
Introduction
Is solar better than wind?
Lack of consultation?
Lack of support for local community?
Lack of transmission lines
Land values and wind farms
Leakage of oil
Lies
Life of wind turbines?
Light aircraft, agriculture and wind turbines
Light aircraft and wind turbine turbulence
Lightning strike
Links
Links: Wind farms and weather
Louder at a distance?
Motivation of proponents and opponents
Mt Emerald Wind Farm aeronautical assessment
Native vegetation
NIMBY; not in my back yard
Noise; my own experience
Noise and wind turbines
Noise complaint
Noise complaints when turbines not operating
Noise sources other than wind turbines
Paucity of information from operators
People driven from their homes?
Perception
Philosophy
Power curve of a wind turbine
Power from all wind farms: combined 2012/01/15 – graph
Power from all wind farms: individually 2012/01/15 – graph
Power surges
Power used when turbine not generating
Pressure in the ears
Pygmy bluetongue lizards
Radar interference
Relative efficiency of turbine - graph
Rare earths
Relative efficiency of turbine - table
Reliability
Renewables are suppressing electricity prices
Roads and road damage
Regional variation in generation
Retail electricity prices
Room (sound) modes
Safety
Self-inflicted problems
Site damage
Social conflict
Solar complements wind
Specific wind power problems
Subsidies
Tasmanian wedge tailed eagles
TV reception and wind turbines
Timing of wind power generation
Too many turbines
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Turbine footing (or foundation)
Turbine wake plumes and aircraft movements
Turbulence from wind turbines
Visual objections
Valid wind power problems
Water requirement
Weather - turbines and surface roughness
Why do people object to nearby wind farms?
Wind farm effect on tourism
Wind farms reduce CO2 emissions
Wind is variable
Wind power generation in one month
Wind power not the answer
Wind power problems
Wind speed range of turbines
Wind turbine litter

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Key word index

This index concentrates on the one most relevant word. (Many subjects cannot be indexed by a single word)...
Abandon
Abandoned 1
Abandoned 2
Abandoned 3
Abatement 1
Abatement 2
Abatement 3
Abatement 4
Aboriginal
Aesthetics
Agriculture 1
Agriculture 2
Annoying
Aircraft 1
Aircraft 2
Aircraft 3
Animals
Aviation
Backup
Barotrauma
Barriers
Base-load
Bats
Benefit
Bees
Birds 1
Birds 2
Birds 3
Birds 4
Blade
Carbon
Cattle
Cement
Climate
CO2 1
CO2 2
CO2 3
Compatibility
Complaint
Coal 1
Coal 2
Concrete
Conflict 1
Conflict 2
Community
Comparison 1
Comparison 2
Confidentiality
Consultation
Compensation
Cost 1
Cost 2
Cost 3
Cut-in
Denmark
Environmentalists
Earthquake
Efficiency
Energy
Environmental
Eagles
Emissions
Envy
Erosion
Evidence
Feedback
Fire 1
Fire 2
Fire 3
Fire 4
Flicker
Footing
Foundation
Fraud
Hot
Hull
Gagging
Generation 1
Generation 2
Geographic
Groundwater
Inequible
Infrasound 1
Infrasound 2
Infrasound 3
Information
Intermittent
Introduction
Land
Lies
Life
Lightning
Lights
Links
Litter
Livestock
Lizards
Motivation
NIMBY
Noise 1
Noise 2
Noise 3
Noise 4
Noise 5
Oil
Payback
Peak
Perception
Philosophy
Place
Power 1
Power 2
Power 3
Prices 1
Prices 2
Prices 3
Property
Radar
Rainfall
Regional
Reliability
Research 1
Research 2
Roads
Safety
Secret
Shadow
Social
Solar 1
Solar 2
Solar 3
Solar 4
Sound
Sheep
Stock
Sound
Space
Subsidies 1
Subsidies 2
Subsidies 3
Sustainability 1
Sustainability 2
Temperatures
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Tourism
Transmission
Turbulence 1
Turbulence 2
Turbulence 3
TV
Values
Variability
Variation 1
Variation 2
Vegetation
Visual
Water, 1
Water, 2
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