Wind power problems,
alleged problems and objections

Valid wind power problems

Noise problems

Power availability and transmission problems

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.

Invasion of space problems

Aesthetic problems

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

At least some wind turbines (and much other modern machinery) 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

Social disruption

Other problems

Is wind power the answer to greenhouse and climate change?

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.

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.

People driven from their homes by wind turbines?

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."

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 3.5km; 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 2.5 km, and then only in ideal conditions. I have visited Waterloo township at least six 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.

A good night's sleep at Waterloo

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.

Compensation

Natural justice demands that people whose amenity has been seriously impacted by noise from 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?

Do wind farms cause social conflict?

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 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

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

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.

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

Paucity of information from operators

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. To do justice to AGL, their SA Manager of Power Development, Tim Knill, has been very helpful.

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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 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.

Do wind farmers consult sufficiently with local communities?

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?

Do wind farmers support local communities?

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.

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

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.

Efficiency of wind turbines

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 Data from Suzlon

Defining efficiency in the case of wind turbines

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

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

Energy in wind

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 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

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.

Subsidies – in regard to wind power

	Facebook, 2013/01/21
	Another subsidy to coal The Victorian government is to spend $4.2 million to strengthen the brown coal mines in Gippsland following flooding; 2013/05/08.

Even so, the fossil fuel industries receive huge amounts in open and hidden subsidies. 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.

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.

Do wind farms get government money?

(Also see Subsidies.)

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.

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.

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

Peak load

Base load

How does this relate to wind power?

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 more than 20% of South Australia's power was produced by wind farms in 2010, 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.

Starfish Hill Wind Farm The fire of 2010/10/30 Image credit Fleurieu Multimedia

Fire hazard without wind turbines It should be recognised that climate change, if unabated by changing from fossil fuels to renewable energy, will result in far greater increases in fire hazard. Scientific American, June 2011, carried an article stating that fire danger in the western US states will increase up to six fold with just one degree higher average temperatures. Lightning strike A common cause of fires in Australia is lightning strike. This risk will be significantly reduced in an area where the ridge-tops are lined with wind turbines that safely conduct the lightning to the earth.

Are wind turbines a fire hazard?

It is quite likely that the frequency of bushfires will be reduced by wind turbines. Wind turbines on the tops of ridges will safely conduct many lightning strikes to earth, while, before the turbines were built, the lightning strikes may well have started fires.

My rough calculation suggests that there have been getting on toward a thousand turbine-years of wind turbine operation in Australia.

The area around the base of all turbines is kept clear of vegetation (in the case of the proposed Mount Bryan Wind Farm at least, the SA Country Fire Service required a cleared area of 40m × 40m), but a fire in the nacelle, on top of the tower, could result in sparks and burning material falling on the ground at a distance from the tower.

Geoff Conway of the Country Fire Authority has said that fires from agricultural machinery at harvest are a far greater fire risk than are wind turbines.

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The turbine access roads would help emergency services access any fire. Some turbines have built-in fire suppression facilities such as automatic flooding with carbon dioxide. This is not used on Suzlon turbines in Australia because of the risk of asphyxiation of workers; protecting life is held more important than protecting assets.

The paragraph on the left is based on advice that I have received on wind turbines and fire fighting from Andrew Allchurch, Gilbert Group Officer of the South Australian Country Fire Service.

Wind power opponents have claimed that Country Fire Service units are not allowed to go within certain fixed distances of turbine fires. This is not true; the decision of how to respond is entirely up to the person in charge at the time.

Much is made by wind turbine opponents of the 300 L of oil in the turbine gearbox being a fire hazard. This would be true if the fire was due to failure of the gearbox, but I had the piece below from Brendan Ryan of Suzlon:

"I worked for Vestas when one of their turbines burned at Lake Bonney. I remember clearly the inspection crew had checked the inside of the gearbox and found no signs of heat damage even though the whole external nacelle was destroyed."

Grass fire stopped at wind farm access road Photo credit; REpower service technicians, The Bluff Wind Farm

Aerial fire-fighting and wind turbines

Personal Communication from David Pearce 2013/02/05; If water bombing aircraft fly above the wind turbines they are too high to be effective.

So far as I have been able to find out the decision of how close to fly a fire-fighting aircraft to a turbine is entirely up the the pilot concerned, who will treat the turbine in the same way as any other obstacle. South Australian Country Fire Services Aviation Services Manager, David Pearce, was reported in the Stock Journal, 2013/01/25, as saying: "As a general rule of thumb, we'll leave about 500 metres between any obstacle and a aircraft, depending on which way the wind's blowing."

There are questions that still need answers:

• Are there any houses near existing wind farms that cannot be protected by fire-bombing aircraft due to nearby wind turbines? If so, how many and where are they?
• Are there any houses near proposed wind farms (particularly the Ceres Project on Yorke Peninsula where the matter is controversial) that will not be able to be protected by fire-bombing aircraft if the wind farm is built? If so, how many?

Television reception and wind turbines

Weather radar interference

Is solar power somehow 'better' than wind power?

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

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

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

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

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. 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 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.

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.

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"

• 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;

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."

Wedge tailed eagles – in perspective It was reported in the Clare Northern Argus 2011/02/23 that "well in excess of 100 birds had been killed". Independent information was that around 75 of these were wedge tailed eagles.

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 says 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."

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

"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

Doctor Cindy Hull answers some questions on birds and wind turbines

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).

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.

Fragmentation of bird habitat

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

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

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.

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...

• Canunda-Lake Bonney
• Brown Hill Range
• Hallett Hill
• Snowtown
• Starfish Hill

• Cape Bridgewater
• Challicum Hills
• Toora
• Waubra

There is more native vegetation at:

• Esperance (WA)
• Mount Millar (SA)
• Waterloo (SA)
• Wattle Point (SA)
• Wonthaggi (Vic)

Turbines scattered through remnant vegitation Turbines can be scattered through scrub, using existing clearings as far as possible

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

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.

Wind home Top Index

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

Image credit Warrnambool Standard and Damian White See text for relevance

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?

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.

Do turbines frighten animals?

Young cattle grazing peacefully beneath wind turbines Toora Wind Farm

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 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?

Wind home Top Index

The wind doesn't blow all the time
Wind is intermittent and variable from time to time
The need for backup

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.

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
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
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.

Wind home Top Index

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.

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 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 Data from Suzlon This graph is explained in Wind speed range of turbines, below

The variability and unreliability 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. When they are not generating some other power station must make up the short-fall.

A part of this problem 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.)

Wind home Top Index

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.

The reliability of wind power

Wind Farm – turbines operable The number of turbines operational and capable of generating electricity at Macarthur Wind Farm Image credit: Vestas

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.)

Wind turbines shut down when the temperature goes above 43 degrees

"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."

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.

Bat deaths

Photo borrowed from the Zoonosis Net site

The article stated that most of the bats were common species including red bats, eastern pipestrelles and hoary bats. What was of great concern was the fact that quite probably only a small percentage of the bats killed were being found.

Little research seems to have been done into this potential problem in Australia. I believe that Brett Lane and Associates of Melbourne wrote the wind industry's 'best practice' guidelines on bat and bird monitoring.

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

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

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.

Honey bee problems?

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.

Wind farms cause power surges?

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.

Can a wind farm change the local climate?

Can wind farms affect rainfall?

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

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?

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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Can wind farms affect temperatures?

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

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

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

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. Lamella 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 lamella (smoothly flowing) wind with a very low sea mist and wind turbines, must be very rare.

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."

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."

Turbine wake plumes and aircraft movements

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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.

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

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 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.

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.

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

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 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?

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

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.

Wind farms greatly reduce carbon dioxide emissions

Emissions intensity on the Australian NEM Graph credit – Professor Mike Sandiford, University of Melbourne; data from the Australian Energy Market Operator (AEMO)

Note the very large decline in South Australia's EI; due almost entirely to the introduction of wind power.

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 Method g CO2e/kWh   Sovacool Weiser Biomass 14-41 74 Coal 960 1000 Gas   540 Hydro 10 8 Lignite   1100 Nuclear 66 10 Oil   760 Solar PV   56 Wind (on-shore) 10 12 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?

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%.

Average abatement intensity from wind generation, kt CO2e/GWh
Wind Capacity	2007	2008	2009	2010	2011	2012	2013	2014	2015
100 MW	0.95	0.92	0.94	0.93	0.95	0.95	0.93	0.91	0.88
1000 MW	1.12	1.10	1.08	1.09	1.09	1.10	1.05	1.03	1.06

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.

'Studies' that are claimed to show that wind power results in increased fossil fuel consumption and higher greenhouse gas emissions

Wind-generated power on 2012/02/25 The top line is the combined generation of all South Australian wind farms, the bottom lines record the output from individual wind farms. This was the most recent day for which data was available at the time I needed a graph for a different purpose; the data were not selected because they were unusually consistent. Image credit "http://windfarmperformance.info/" and Andrew Miskelly

• They contradict the South Australian experience where electricity consumption has increased while emissions have declined due to the construction of wind farms;
• Mr. le Pair claims that the great variability of power from wind farms causes continual starting and stopping of backup generators. Wind power is not highly variable, as can be seen from the example graph on the right, and its variations can be, and are, forecast;
• Can the reader believe that the people who run the world's power supplies, in many different countries, could be so stupid as to introduce wind power if it was going to lead to an overall increase of fossil fuel use?

Visual objections to wind farms

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 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

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)."

"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."

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.

Water requirement of wind farms

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.

Do wind farms turn away tourists?

"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."

Land values are hardly affected by wind farms

Median prices for Cape Bridgewater/Cape Nelson – commissioned 2008/09   Median prices for Challicum Hills – commissioned 2003   Median prices for Codrington – commissioned 2001   Median prices for Toora – commissioned 2002   Median prices for Waubra – commissioned 2009   Median prices for Wonthaggi – commissioned 2005   Median prices for Yambuk – commissioned 2007

The graphs on the right were created using data from propertyvalue.com.au by Victorian Greens MP Greg Barber (see here). Each is in an area where a wind farm has been built. The graphs clearly show that there are no long-term declines in land values associated with wind farms. I have produced similar graphs from South Australian property values (using realestate.com.au), but as they all show the same trend as Greg's graphs it seems superflous to display them here.

Informative link Mike Barnard wrote a summary of studies of the effect of wind farms on property values on Quora. In general he found evidence of some short-term, but no long-term, decreases in the values of properties near wind farms. Tales of impending disaster and land values Anti-wind power groups like Heartland Farmers, a group that is trying their best to make the proposed Ceres wind farm look like an impending disaster, must drive land values down to some extent. On the other hand, at nearby Snowtown, where there is a wind farm that everyone is happy with, there is no cause for land values to decline.   Wind home Top Index Abandoned homes? Also see People driven from their homes by wind turbines?, on this page.

Australia

"This study investigated eight wind farms across varying land uses (rural, rural residential, residential) using conventional property valuation analysis. Two wind farms were selected in NSW and six in Victoria. The main finding was that the wind farms do not appear to have negatively affected property values in most cases. Forty of the 45 sales investigated did not show any reductions in value. Five properties were found to have lower than expected sale prices (based on a statistical analysis)."

In the Australian case and concerning the land on which the turbines are built, turbines are usually on the tops of hills where the land is too steep to crop, so no cropping land is usually lost. Animals, both wild and domestic, quickly get used to turbines and will happily graze right under them. The value of a property is dependent on its earning potential and having turbines on a property greatly increases earning potential. The licensing fee normally paid by turbine operators to land owners varies from at least $4000 per turbine per year up to $10 000 at (Dalby, Queensland) and possibly as high as $14 000. (See also elsewhere). So fairly obviously values of land having turbines on it are likely to increase.

Waubra

In the Ballarat hearing of the Senate inquiry into the impact of wind farms (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.

Overseas

In the USA the Renewable Energy Policy Project reported on a massive survey titled "The Effect of Wind Development on Local Property Values" in May 2003. The report stated that: "Although there is some variation in the three Cases studied, the results point to the same conclusion: the statistical evidence does not support a contention that property values within the view shed of wind developments suffer or perform poorer than in a comparable region."

Again in the USA, a study named "The Impact of Wind Power Projects on Residential Property Values in the US", published by the Ernest Orlando Lawrence Berkely National Laboritory and dated December 2009 stated:

"The present research collected data on almost 7,500 sales of single family homes situated within 10 miles of 24 existing wind facilities in nine different U.S. states. The conclusions of the study are drawn from eight different hedonic pricing models, as well as both repeat sales and sales volume models. The various analyses are strongly consistent in that none of the models uncovers conclusive evidence of the existence of any widespread property value impacts that might be present in communities surrounding wind energy facilities. Specifically, neither the view of the wind facilities nor the distance of the home to those facilities is found to have any consistent, measurable, and statistically significant effect on home sales prices."

The UK Centre for Sustainable Energy published a document Common concerns about wind power that included a section on "Wind turbines and property prices". It spoke of an "anticipation stigma" regarding adverse effects on land prices that exists during the planning and construction of wind farms, but said that "a great deal of research in the UK and abroad shows that there is no devaluation in property prices nearby once a wind farm is operating".

The UK Royal Institute of Chartered Surveyors (RICS) summarised a number of surveys under their 'Frequently asked questions' – 'Do wind farms affect property values?' They stated that "There is no difinitive answer to this question".

The Clean Energy Council provides a fact sheet on wind farms and land values.

General

Photo acknowledgment – treedork, Flickr

Wind turbine litter

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.

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

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.

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.

Do wind farms replace coal-generated electricity?

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 Figure from the Australian Energy Market Operator (AEMO) 2012 SA Supply and Demand Outlook report

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?.

How does wind power compare to roof-top solar?

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?

Power curve of a Suzlon S88, 2.1 MW turbine 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 Photo credit Helen Simpson, Osprey Photography

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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?

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

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.

Confidentiality

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 attempting 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.

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.

Self-inflicted problems

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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.

Denmark and wind power

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".

Too many turbines

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.

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

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.

Safety

Graph credit UK Centre for Sustainable Energy

"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."

Wind farms are not the cause of rising electricity prices

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.

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.

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. Consumption of electricity continues to rise (in Australia and world-wide), this leads to a need from the building of expensive new electricity transmission and distribution infrastructure. Ultimately this must be paid for by the end consumers of the electricity. Those who claim that power prices would fall without a carbon tax are simply liars.

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

Earthquakes and wind turbines

No wind turbines damaged in major 2011 Tohoku Japanese earthquake

"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."

Also see the Wikipedia article.

Are agriculture and wind farms compatible?

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State	Agricultural production $m	Installed wind power MW
California	31 835	5 549
Texas	16 498	12 212
Iowa	14 653	5 137

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.

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.

Light aircraft, agriculture and wind turbines

Aerial spraying of a cereal crop in Mid North South Australia
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, and my information is that 2800 wind turbines coexist happily with intensive cropping in the US state of Iowa.

Collision between aircraft and turbines is an obvious risk, although so far as I have been able to discover there seems to have never been any, nor has any aircraft crashed due to the turbulence on the down-wind side of a wind turbine. (At the end of 2012 there was 274GW of installed wind capacity world-wide; the equivalent 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; the Mt Emerald assessment, below, deals with this.

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Aerial Agriculture Association of Australia

Collisions While there are around 200 000 utility scale turbines in the world, so far as I have been able to find out there has never been an aircraft accident due to either collision with a turbine or the turbulence created by turbines. Meteorological towers However, 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

"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."

"... 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

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

"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."

Light aircraft and wind turbine turbulence

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.

Pressure in the ears

Camping under wind turbine at Waterloo Wind Farm

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.)

Feeling of place (or personal space)

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.

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

(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.

Motivation of proponents and opponents

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.

• 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.

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.

Philosophy

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

Economic costs and benefits

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

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.

Wind power problems, alleged problems and objections: links

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.

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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