For those of you that know anything about frost prevention, or have even seen aircraft engines like these mounted on poles in an orchard, this paper will make perfect sense to you. It makes perfect sense to me. According to PNAS, this paper was edited by the late Dr. Steven Schneider, making it even more interesting. – Anthony
From a University of Illinois press release:
CHAMPAIGN, Ill. — Wind power is likely to play a large role in the future of sustainable, clean energy, but wide-scale adoption has remained elusive. Now, researchers have found wind farms’ effects on local temperatures and proposed strategies for mediating those effects, increasing the potential to expand wind farms to a utility-scale energy resource.
Led by University of Illinois professor of atmospheric sciences Somnath Baidya Roy, the research team will publish its findings in the Proceedings of the National Academy of Sciences. The paper will appear in the journal’s Online Early Edition this week.
Roy first proposed a model describing the local climate impact of wind farms in a 2004 paper. But that and similar subsequent studies have been based solely on models because of a lack of available data. In fact, no field data on temperature were publicly available for researchers to use, until Roy met Neil Kelley at a 2009 conference. Kelley, a principal scientist at the National Wind Technology Center, part of the National Renewable Energy Laboratory, had collected temperature data at a wind farm in San Gorgonio, Calif., for more than seven weeks in 1989.
Analysis of Kelley’s data corroborated Roy’s modeling studies and provided the first observation-based evidence of wind farms’ effects on local temperature. The study found that the area immediately surrounding turbines was slightly cooler during the day and slightly warmer at night than the rest of the region.
As a small-scale modeling expert, Roy was most interested in determining the processes that drive the daytime cooling and nocturnal warming effects. He identified an enhanced vertical mixing of warm and cool air in the atmosphere in the wake of the turbine rotors. As the rotors turn, they generate turbulence, like the wake of a speedboat motor. Upper-level air is pulled down toward the surface while surface-level air is pushed up, causing warmer and cooler air to mix.
The question for any given wind-farm site then becomes, will warming or cooling be the predominant effect?
“It depends on the location,” Roy said. “For example, in the Great Plains region, the winds are typically stronger at night, so the nocturnal effect may dominate. In a region where daytime winds are stronger – for example a sea breeze – then the cooling effect will dominate. It’s a very location-specific thing.”
Many wind farms, especially in the Midwestern United States, are located on farmland. According to Roy, the nocturnal warming effect could offer farmland some measure of frost protection and may even slightly extend the growing season.
Understanding the temperature effects and the processes that cause them also allows researchers to develop strategies to mitigate wind farms’ impact on local climate. The group identified two possible solutions. First, engineers could develop low-turbulence rotors. Less turbulence would not only lead to less vertical mixing and therefore less climate impact, but also would be more efficient for energy generation. However, research and development for such a device could be a costly, labor-intensive process.
The second mediation strategy is locational. Turbulence from the rotors has much less consequence in an already turbulent atmosphere. The researchers used global data to identify regions where temperature effects of large wind farms are likely to be low because of natural mixing in the atmosphere, providing ideal sites.
“These regions include the Midwest and the Great Plains as well as large parts of Europe and China,” Roy said. “This was a very coarse-scale study, but it would be easy to do a local-scale study to compare possible locations.”
Next, Roy’s group will generate models looking at both temperature and moisture transport using data from and simulations of commercial rotors and turbines. They also plan to study the extent of the thermodynamic effects, both in terms of local magnitude and of how far downwind the effects spread.
“The time is right for this kind of research so that, before we take a leap, we make sure it can be done right,” Roy said. “We want to identify the best way to sustain an explosive growth in wind energy over the long term. Wind energy is likely to be a part of the solution to the atmospheric carbon dioxide and the global warming problem. By indentifying impacts and potential mitigation strategies, this study will contribute to the long-term sustainability of wind power.”
###
Here is the paper on PNAS: http://www.pnas.org/content/early/2010/09/28/1000493107
Impacts of wind farms on surface air temperatures
+ Author Affiliations
Department of Atmospheric Sciences, University of Illinois, 105 South Gregory Street, Urbana, IL 61820
-
Edited* by Stephen H. Schneider, Stanford University, Stanford, CA, and approved August 13, 2010 (received for review January 15, 2010)
Abstract
Utility-scale large wind farms are rapidly growing in size and numbers all over the world. Data from a meteorological field campaign show that such wind farms can significantly affect near-surface air temperatures. These effects result from enhanced vertical mixing due to turbulence generated by wind turbine rotors. The impacts of wind farms on local weather can be minimized by changing rotor design or by siting wind farms in regions with high natural turbulence. Using a 25-y-long climate dataset, we identified such regions in the world. Many of these regions, such as the Midwest and Great Plains in the United States, are also rich in wind resources, making them ideal candidates for low-impact wind farms.
==============================================================
h/t to WUWT readers M. White and Scarlet Pumpernickel
Is it still true that wind farms kill many birds? I have long questioned the value of these installations, especially since learning that they require supplemental electricity about 80% of the time. The assumption seems to be that wind farms are beneficial and effective, that they should be built, and that they are inevitable. The data I have seen contradict that assumption. Anything out there to show why they should be built?
With appropriately positioned wind farms and thermometers, global warming will continue forever.
So windmills will be damaging the natural micro-climate. Not only are these monstrosities ugly as sin, they chop up birds, kill bats by embolisms, and now mess up the climate.
Exactly why are we pursuing this undependable, expensive, expensive to maintain ‘option’?
Oh, yeah: because government subsidized industries can make big buck$ off it.
I like the idea of using wind turbines to help mix low-level air depleted of CO2 with high-level air that has more abundant CO2. Some plants, such as corn, are so voracious that they lower CO2 levels in the air around them on days with no breeze to the point that they quit growing. So air mixing not only will impact termperature regimes, but CO2 concentrations, which will help stimulate plant growth. Of couse, on days with absolutely no wind, turbines won’t be turning so there will be no plant growth and no electricity generation.
“According to Roy, the nocturnal warming effect could offer farmland some measure of frost protection and may even slightly extend the growing season”
Some measure of frost protection when the wind is blowing and you’re lucky enough to be down wind. Surely frosty nights tend to be windless?
Another probable source of mixing air layers is along the corridors of the Interstate Highways and other major roadways where large trucks stir vortexes of air in the wake of their passages. The effect can be seen along the highway shoulders by the retardation of frost and snow accumulation in relation to the adjacent fields and woods.
It would be interesting to discover what effects there have been by the changeover from railroad steam locomotives to diesel-electric locomotives versus the increses in highway diesel trucking.
The pollution from merchant ships has already been the subject of environmental studies and criticism, but the air mixing and wake effects of this shipping upon air temperatures and sea surface temperatures is an open question.
Frost benefits? I think frosts occur when there is no wind!
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And there is also the effect of reduced wind-chill, due to reduced wind velocity behind the rotors. The ground can suffer wind-chill, if it is moist, and so a lower wind speed will equal a warmer surface temperature. Shelter in the lee of a hill, and you will get the idea.
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And here is another thought experiment: – will reducing the wind speed also change the wind direction?
The winds blow in circles around low-pressure systems, due to a convenient balance between Coriolis force and Centrapetal force. If you reduce the Centrapetal force (because you have reduced the wind speed by taking its energy as electrical power) the wind will blow more towards the center of the low pressure system. This will have the effect of allowing the low pressure system to fill more rapidly – a bit like a vortex in a bath-tub, when you interfere with the vortex with your finger. And how will this effect our weather systems??
“” Help !! Its worse than we thought, the Greens are going to change entire weather systems, and we are all going to die !! “”
Or some such alarmist rant…
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Wind farms are causing dangerous climate change. My model says that wind farms in Texas cause more floods in Pakistan.
Wind energy is likely to be a part of the solution to the atmospheric carbon dioxide and the global warming problem.
Talk about talking out of both sides of his mouth. He himself points out that “the nocturnal warming effect could offer farmland some measure of frost protection and may even slightly extend the growing season.” Doesn’t that mean warmer is better?
Wow, they’re really worried about some slight, localized cooling/warming effect of these expensive, pretty much useless, ugly, loud, bird-killing machines?
“The time is right for this kind of research so that, before we take a leap, we make sure it can be done right”. Done right? How about making sure it should be done at all?
“Many of these regions, such as the Midwest and Great Plains in the United States, are also rich in wind resources, making them ideal candidates for low-impact wind farms.”
========================================================
lol, low-impact………how about no impact. I went to El Dorado, Ks, last week, (near Wichita) and drove by seemingly hundreds of those silly things, a nice constant breeze blowing…….not a one turning…….sigh.
“Anything out there to show why they should be built?”
Just unfounded panic, including large subsidies..
Given that I’m near a research turbine at the University of Delaware in Lewes, DE, I wonder what the effect is from costal or off-shore turbines where you have onshore and offshore winds from the differential heating/cooling of land/water.
I’ve joked to people that Lewes couldn’t afford air conditioning so they just build a giant fan. So far the turbine is off more than it’s on. The University had an open house this weekend and I asked a rep of the company that built it why, and they said that it really wasn’t intended to be fully operational, but to be a research tool to test out winds and corrosion issues for off shore wind farms.
Butt Ugly as well high up in the pristine WV Alpps…+ like Mr goddard says..they cause flooding in Pakistan, Can you prove him wrong?
Dr. John M. Ware says:
October 5, 2010 at 3:45 pm
“Is it still true that wind farms kill many birds? I have long questioned the value of these installations, especially since learning that they require supplemental electricity about 80% of the time. ………”
========================================================
The supplemental energy required is dependent upon the energy produced by the wind farms. Which, of course, is dependent upon the wind and amount of windmills. Wind is horrible for reliance when it comes to anticipation of wind. However, the sad part of the story is they must be backed by gas or oil fired generation plants. You can’t use the cheaper coal or nuclear, because you can’t take them up and down quick enough to respond to the wind changes. Currently, in my location, it costs about 3 cents/kwh to produce coal fired electricity. 5 cents for nuke. Gas…..13 cents/kwh…..wind…..17 cents/kwh.(Costs vary from location to location.) Worse yet, when one considers the duplicity on transmission requirements,(while gas fired plants are not new, they weren’t widely used because of costs, so we have to construct many more for the backup.) energy used to manufacture, construct and maintain the duplicity, and costs and energy to do the same individually, there is no savings, CO2, energy or money. A giant waste of time, energy, money and effort. To have some real fun, look at the life expectancy of the bird killing monstrosities and realize, very soon, if we are to maintain our course, we’ll have to do it all over again. Nice
Warmer is better for growing when “warmer” means higher minimums.
In this case there is no contradiction, as their is no nett change in energy, just a more mixed arrangement, which happens to suit growers. The windmills aren’t generating any heat, just arranging it differently.
Unless you think glass greenhouses contribute to global warming too, by somehow “making” extra heat.
“Wind energy is likely to be a part of the solution to the atmospheric carbon dioxide and the global warming problem.”
=========================================================
That’s funny. Do they figure in the redundancy necessary with they figure the CO2 calculations of creating these idiotic mechanisms? Do they have any idea what it takes, in terms of CO2 emissions, to build two distinct generation plants and transmission lines? The maintenance?
There’s never a free lunch, right? Since the entire planet is basically a solar powered biosphere, it would seem that extracting significant amounts of energy from it to create electricity, has to have an impact in the energy budget. If you get enough of these things spinning there will be an impact that nobody has thought of yet.
Then you have to consider the impact on the behavior budget. Farmers are getting 8K per tower every year. I’ve seen wind farms that stretch clear across the horizon, three deep. Farm senators surely smell this loot and will do whatever it takes to keep this revenue stream flowing to their constituents. Only in America can you grow economically useless turbines in the middle of a corn field created to make economically useless ethanol and reap a fortune in the process.
These things would never be growing out of the plains without the political fertilizer being thrown on them.
I wondered about the design of those huge windmills, they look inefficient, but not an engineer couldn’t tell. I recall the Dutch perfected the windmills they had and that extra power fuelled their rise to trading hub – is anything bigger than that necessary? They look as if a stiff breeze is all they need to get them going. Are they dangerous for birds and bats?
The windmills the US farmers had before the companies put in their lines, for ‘free’ and got them to take down their own, were small.
Mods, thanks.
This seems like basic meteorology. The coldest nights are when there is no wind and the hottest days are when there is no wind. I often wonder why people who push so-called green technology always ignore already well-known scientific facts. And then I remind myself of the money involved and wonder no more.
I posed a question one timeto a wind generator “expert” as to why only three blades? it seems to me that having 6 or even 12 blades would allow you to capture more energy from the passing wind that you miss only having three. Just look at any old pump windmill used by ranchers and farmers and they have 20 blades.
She was dumbfounded at the question because nobody had ever asked her that. she didn’t know, couldn’t cite any calculations or engineering reasons to justify 3 blades other than perhaps it is more cost effective to manufacture 3 blade turbines rather than “more than 3 ” blade turbines.
Seems to me that with more blades you create a larger visual barrier, forbidrs and creating a larger sonar signature for bats and perhaps generate more electricity per tower.
Any one?
Generally speaking frost damage to crops is only an issue on a small number of nights each year. Nights where unseasonable and damaging frost is likely typically are cold and clear with no cloud cover and little or no wind. Wind turbines won’t be running in those conditions so they won’t help prevent frost damage. The farmer doesn’t care about effects on average nighttime temperatures. They only care about increasing nighttime temperatures on those few occasions where frost damage is a likelihood.
The claim could be rescued however if it was proposed to run power backwards through the turbines in times of frost and use them as giant fans to stir up the air and protect the crops. That would require windmills specifically designed with this application in mind.
“nocturnal warming effect could offer farmland some measure of frost protection”
===================================================
No wind = frost
No wind = no windmills
No windmills = no wind – frost
OK, I’m within the Univ of IL system, so I have a dog in this fight!
a) Turbines are known to cause a strobe-effect called “turbine flicker.” Here:
[youtube=http://www.youtube.com/watch?v=MbIe0iUtelQ&fs=1&hl=en_US]
b) Strobe effects from turbines are implicated in triggering photosensitive epileptic seizures, here is an example from the medical literature:
http://www.ncbi.nlm.nih.gov/pubmed/18397297
c) These turbines are an abomination. Present-day hysteria over climate change brings to mind the episode of hysteria during the Salem witch trials in the late 1600’s:
http://www.salemwitchtrials.com/salemwitchcraft.html
There is quite a bit of controversy within the UI system about climate change, but the warmists, by far, rule the roost.
Matt :
October 5, 2010 at 5:16 pm
I’d guess its an issue of weight of the extra blade(s) requiring an increase in engineering in the central rising pillar as well as of cost of the additional blade not being offset by yet more subsidy money.
I hope that made sense.
I wonder if there might be a wind farm associated drying effect that might impact nearby irrigation requirements….
This is ridiculous. Windmills take energy from the air and convert it to electricity. The only possible result is less energy in the air which must result in lower temperatures and/or lower wind speed. Remember that these things are huge, producing about 2 megawatts of power each. A lot of energy transfered at the interface along blades. One thing is certain, they (windmills) never increase the temperature of the air by themselves.
Knowing the initial conditions pressure, relative humidity, temperature and air speed and what power is generated you could assume 100% efficiency and predict the final conditions of the air through the turbine. That’s is why we have thermodynamics courses.
I think windmills act like dampers on the surrounding weather so it may not be the blessing we are told about. The energy ends up somewhere but where and in what form? Is this harmless?
Barry
“For example, in the Great Plains region, the winds are typically stronger at night, so the nocturnal effect may dominate.”
Let me get this straight then… The wind blows predominantly at night in the mentioned location. The wind blows primarily at night in most locations, right? So how do we make use of this night time electricity? Become naked mole rats and work and live in darkness? I propose we use the electricity produced by windmills to pump water back up into hydroelectric reservoirs at night as that is the only way to store the power for daytime use.
I agree with Sandy, Alex and Wade that frost occurs mainly on still, windless nights (at least that is the case where I live for frosts that you would want to influence, for example in vineyards). On these nights the wind turbines would not be turning (unless Roy is proposing that they be powered by electricity in order to alleviate frost…?!?!).
Is Roy talking about something else, e.g. reducing a (say) -20C frost by a bit? Is this of any use to agriculture in North America? If not, I don’t have a clue what Roy is talking about.
An interesting analysis of the economics of a wind farm are posted here:
http://www.beaconhill.org/BHIStudies/Windmills2004/WindFarmArmyCorps.pdf
Here’s the summary:
“The economic costs of the project exceed the benefits by $209 million.2 Based on these numbers, it does not make sense, from a societal point of view, to build the project.”
and
“From the developer’s perspective, the project is much more appealing. Despite being
economically undesirable from a societal point of view, the project would be privately profitable because of the very large subsidies that it would receive. The most important of these would stem from the “green credits” that result from recent changes to the law in Massachusetts: Electricity consumers in the Commonwealth must buy a growing proportion of their electricity from “new renewable” sources, requiring them, in practice, to pay a premium for their power.”
Sandy says:
October 5, 2010 at 4:04 pm
“According to Roy, the nocturnal warming effect could offer farmland some measure of frost protection and may even slightly extend the growing season”
Some measure of frost protection when the wind is blowing and you’re lucky enough to be down wind. Surely frosty nights tend to be windless?
Frosty nights, at least here in New England with trees and valleys, are typically clear and windless – near the ground. An air inversion sets up that often is only dozens of feet thick. Wind may be blowing up at wind turbine height and I suppose the blades can create enough turbulence to stir things at ground level. Well, except that in New England people put wind turbines on mountain ridges, putting one in a valley is plain stupid….
Windmills are much more efficient bat-swatters than Granny with a tennis racquet. The reduction in bats experienced in the last decades coincides with deployment of large-scale commercial wind turbines. Less bats = more insects = more diseases, like EEE, West Nile, malaria, ebola, etc.
Turbines kill bats even when the bats are close to them; direct hits are not needed. They die by embolisms caused by pressure differentials, and also the echolocation ability is destroyed by damage to their ears.
Everything has consequences. Burning petroleum or nuclear power generation seem to have the softest impact on the environment. AND CO2 production is, of course, good for the planet since we are in a CO2-starved era.
bubbagyro says: Windmills are much more efficient bat-swatters than Granny with a tennis racquet. The reduction in bats experienced in the last decades coincides with deployment of large-scale commercial wind turbines. Less bats = more insects = more diseases, like EEE, West Nile, malaria, ebola, etc.
Had not heard of that… I love bats (as I hate mosquitoes). One bat can eat 1,000+ mosquitoes in a night. Best thing you can do to keep mosquitoes down near a rural location is put in bat houses…
@CRS, Dr.P.H: OMG! I’d heard about the ‘woosh’ but not the flicker. That would drive me nuts in no time. That video makes it very clear to me that if a wind farm was built next to my home it would constitute a ‘taking’ as I could not live there anymore and anyone with a brain would not want to buy the place. GAK!
What? I’ve never heard that. Sure doesn’t happen at ground level here. I tried finding something about that in Google, but only came across references to “low level jets” being stronger at night. I figured those would still be too high, but I found http://www4.ncsu.edu/~sbasu5/Storm_WE_2008.pdf and that appears to be what they’re talking about:
100m – that’s certainly in reach of a good sized turbine.
Be careful of what you wish for. Well, maybe they aren’t wishing for stronger winds at night.
As I recall, wind farms got their start when the world was going to end because we were running out of oil. Not “peak oil”, that hadn’t been invented yet, it was just “running out”. I’m hazy on the time frame, but I’m pretty certain it was just after the world was going to end because of a new ice age, but before the world was going to end because of ozone depletion. I’m prettu sure that was the order, but maybe the world was going to end because of acid rain and then ozone? No… I think ozone was before acid rain.
In any event, all the talk was about renewable energy sources and that’s where wind and solar started to get traction. When it turned out that we weren’t running out of oil, wind and solar kinda faded away because the world was going to end from all sorts of things but they got resurrected when the end of the world prophecies started to hype CO2 and global warming.
I’ve asked the same question then as I do now. Does anyone really think that a substantive amount of energy can be extracted from the wind without affecting climate? Back then, the answer was “yes, but what choice do we have?”. The answer now is “yes, but if we ignore how frosts actually occur we can spin it as a benefit”.
Any farm kid (or avid golfer) can tell you what type of weather results in frost, and it isn’t the kind that makes wind mills spin. The spin that these researchers have on frost mitigation is right up there with the sales guy in a loud shirt trying to sell you the clothes you are already wearing.
Olaf Koenders says:
October 5, 2010 at 4:20 pm
“Anything out there to show why they should be built?”
Yep. On the eastern parts of the South Island of New Zealand we have a hot drying wind parochially called the Nor’wester. Its source is an air mass that picks up moisture from the Tasman Sea and dumps it as heavy rain on the Southern Alps then continues eastwards as a strong wind that dries everything in its path.
There also is much need for agricultural irrigation on the Eastern parts of the South Island and happily the few wind turbines built spin flat out while the Nor’wester blows providing power to the grid that feeds the big water pumps that drive the irrigation systems…..
Our other main electricity source is hydroelectric which is very sustainable. Still the greens insisted we having these ugly wind farms perched up on the hilltops overlooking our landscape. And that is the price we pay to save er – something pretty insignificant.
I think if there are too many windmills, the air currents will be affected. This could truly change the dynamics of our global climate environment.
Maybe this could be used for Eco warfare in the future. The Russians and Canadians could build huge wind farms, depriving the US and China their share of cold air.
I think someone needs to seriously consider this possibility. I wonder if I could get a multi-million dollar grant from the DOD to study it?
E.M. SMITH,
We need to know you insight to the “Wave Power”. My calculations have it close to 65,000 generators for the minimum of California (23,000MW). I can not see any serious impact other than needing to boat out through these wave farms.
Reference:
http://chiefio.wordpress.com/2010/09/27/grid-connected-wave-power-in-usa/
In case you missed it. Pics of turbines lifting warm moist air from below and creating fog. Negative feed back??
http://www.dailymail.co.uk/news/article-1251721/Pictured-The-stunning-micro-climate-sea-fog-created-Britains-windfarms.html
We haven’t investigated all contributors:
– addition of heat to water sources by hydro-electric dams
– reflected radiation from solar panels heating adjacent power lines and producing EMF
– chemical heating from the decaying fish hitting wave generated power blades
We MUST abandon all artificial energy and return to Gaia!
How would the mixing effect cause a different outcome during the day and during the night – by disturbing convection currents perhaps? Generally speaking the warmest air is where it is thickest – near the surface (up to a point). If turbines cool in the daytime and warm in the night they must be aiding convection when it is sunny and slowing it down when it is dark.
Or is it dependent on the source of the heat? During the day the radiation is predominately coming from above and at night it is coming from the ground. Could the more turbulent air be acting ever so slightly like insulation and reducing surface temps during the day and maintaining them at night?
The laws of physics (thermodynamics) expalain it all. I agree with “Enginear” post 6:30 PM. He said it all.
You can’t take energy out of the atmosphere without lowering its wind speed or temperature. The Conseration of Energy Law says so.
E.M.Smith says:
October 5, 2010 at 7:22 pm
@CRS, Dr.P.H: OMG! I’d heard about the ‘woosh’ but not the flicker. That would drive me nuts in no time. That video makes it very clear to me that if a wind farm was built next to my home it would constitute a ‘taking’ as I could not live there anymore and anyone with a brain would not want to buy the place. GAK!
======
REPLY:
Yeah, it surprises people! I guess I’m lucky, I’m a public health expert with photosensitive epilepsy, so I have a dog in THAT fight as well!!
Here’s the .pdf of the entire paper “Wind turbines, flicker, and photosensitive epilepsy: Characterizing the flashing that may precipitate seizures and optimizing guidelines to prevent them”
http://www.mfe.govt.nz/rma/call-in-turitea/submissions/186changeappendix3.pdf
These things are a curse. A bad solution for a nonexistent problem IMHO.
Oh I get it local warming is good because it helps reduce frost but global warming only has negative effects. My guess is that if we were talking about the local warming effects of nuclear power plants it would be spun as a negative.
Wind farms and bird killing
A lot of the bird killing studies originate with a Dr. Smallwood doing research on the Altamont Wind Farms in CA near Tracy and Livermore CA. I see the wind turbines everyday.
Dr. Smallwood’s research is too be highly questioned. For example: the bird killing according to him has gotten worse even though there are fewer turbines working here each year and they break down and are not replaced. The burrowing owl killing was huge in the winter months when the wind barely blows contributing only 3% of the yearly energy production during the worse “bird killing time”. Further, even though I drive through the wind farm every day twice a day on my long commute – I’ve never seen a single researcher ever walking the grounds or a single bird getting chopped. I’ve even witnessed birds flying around the blades with no apparent problem. I’m not saying that a few have been killed – but I believe the problem is grossly overstated. The research is so suspect that I took pictures the previous winter of all the days that the windmills were not turning to see what his research would say about the winter deaths. I can’t wait till his next paper. He gets a lot of money to walk around these beautiful windmills looking for bird carcasses.
Please remember – I have zero agenda either pro- or anti- windmills. I actually like how they look, they are not very noisy at all unless you are standing within a few hundred feet, and I wish they were the answer for our energy needs. However, the windmills here generate good energy during the summer months and are virtually “off” all winter when so much of the bird killing occurs. So unless this country doubles it’s energy capacity to compensate for when the wind doesn’t blow for 6 months, this is not a complete solution. The reason the windmills do not turn during the winter is because the San Joaquin valley temperature vs. the coastal San Fran Bay Area temperature is not great. In the summer time there is a huge temperature differential and thus a LOT of wind.
CRS, Dr.P.H
Thanks for that video. I have never read or heard of that type of pollution. How irritating must that be to the occupants.
Matt at 5:16 and Robert at 5:57
I used these words to do a Google search:
“wind turbines” more “three blades”
There were about 11,200 results
At the time this was the eighth result.
http://www.aerostarwind.com/Literature/Why%20Two%20Bladed%20Rotors%20Make%20Sense.pdf
“You may recall from a physics class the experiment were you hold a bicycle wheel by its axle while someone spins the wheel. If you try to move the axle forward or back the wheel will tilt off to one side.”
and . . .
“Large gyroscopic forces are inherent in rigidly mounted three blade rotors. On large wind turbines these forces are reduced by slowing the yaw rate to a very low value. This is accomplished by using a motorized yaw drive with a large gear reduction. Most small wind turbines don’t have yaw drives because it would increase the expense and complexity of the turbine. For a small free yaw turbine, the most common solution is to build a very strong, and heavy, machine. Because the tower also has to be strong enough to resist these forces, it too must be designed to handle the loads. The increased weight often results in increased cost.
A properly designed two bladed rotor can substantially reduce these large gyroscopic forces.”
Enginear says:
October 5, 2010 at 6:03 pm
Why not? The wingtips are cutting through the air at a hundred miles per hour or so, that ought to cause enough frictional heating and turbulence (which dissipates as heat) to be worth some concern.
Since I live out here on the Great Plains and have many windmills located nearby I just have to comment on this whole silly discussion.
First of all how do you measure air temp accurately when the air is turbulent? Have suicidal pigeons with thermometers tied to them fly through the windmills?
If you want to mix the air from high to low the blades would have to look like giant soup spoons. Probably not too effective but send me some money for a study and I will build a demo unit.
Bird kills? Ha! We have waaaay too many Canadian geese around here anyway. I think we should surround the windmills with sloughs and put permanent decoys up. Give the meat to the school lunch program or something. That tough greasy bird will need a little tenderizing anyway, so a good smack with a giant blade will probably do the job.
Hadn’t heard about the issue with bats, and I do hate mosquitos, however just how high do bugs fly? Are bats actually flying 300ft off the ground in pursuit of bugs? Heres an idea! Put a couple street lights a few hundred feet away from the big bad windmill and use some of that power to light them up. Problem solved! It will be a virtual bat buffet with all the bugs flying around the light.
Hey, lighten up a little, this is funny stuff!
Matt,
A three-bladed rotor as compared to a two bladed will transmit much less vibration to the mast. The three-bladed rotor has constant moment of inertia with respect to horizontal and vertical axes, a two bladed has a large variation.
The number of blades is a compromise between efficiency and cost, weight, etc.
If there were gains in having more than three blades on a large turbine, we would see such turbines everywhere. Engineers know how to calculate…
I worked for a wind machine company in California for 7 years. These machines were specifically for frost protection and ran on gas, propane, diesel and electricity. The concept has little to do with air movement or heat generated by friction. At night the air is generally warmer as warm air rises and is replaced by cool air at lower levels. This is the inverse of daytime air temperatures, which are warmer near the ground and cooler at higher levels. The wind machine blows the warmer air from 30 to 40 feet above back down toward the ground.
At best, it will heat the ground level by 6 degrees. When temperatures go below 26 degrees there will be crop and bloom damage, even when conditions are right for the wind machine to be most effective. Running the machines at those temps are an attempt to save the trees themselves.
Our company manufactured a very large two bladed fiberglass fan to go on our machines. The fans were light and efficient. but the engines were very large, such as the Ford 450s, which are no longer used in cars. Smudge pots worked better but were stinky and produced oily smoke. Most areas don’t allow them anymore, even though frost conditions occur for a total of a couple of weeks each year.
I don’t see how windmills can help much with frost protection. My understanding is that the blades catch the wind, causing them to turn and generate electricity. If it’s windy, I don’t think there would be the inversion layer needed to blow down warmer air. The air wouldn’t be sucked from behind the fans and blown out the front at a faster speed than the wind itself. Please explain if I’m wrong.
Nothing new here – MIT reported back in March this year – . Authors Prinn and Wang studied both onshore and offshore wind farms, and concluded that onshore farms would reduce heat transport processes that move heat away from the Earth’s surface,and given the projected growth in wind farms, this could have a significant impact globally.
It should be fairly obvious that wind turbines absorb wind energy,and must therefore reduce wind speed, but the effects of this aspect haven’t been fully studied yet. It’s clear that large-scale expansion of wind farms is a form of geo-engineering – we should be sure that ALL the aspects and impacts of any such expansion is studied in detail and understood.
Finally, I can’t think of one thing that’s positive about wind farms. Power stations, factories and mines can (and in some cases are forced to be) hidden from long-distance view. Wind farms by their very nature have to be sited prominently to catch the wind; they despoil the coast and countryside, kill birds,and employ very few. Luckily they’ll all wear out in around 20 years, and perhaps common and commercial sense will have prevailed by then, and they’ll be quietly removed and forgotten as an experiment that went wrong. Unfortunately we’ll have all paid the price for these monstrosities and their ultimate scrapping.
>>A three-bladed rotor as compared to a two bladed will transmit
>>much less vibration to the mast.
But why not have more blades? Prop aircraft have always moved towards multi bladed props, because they are more efficient. Is it hub complexity that restricts windelecs to three blades?
http://media.defenseindustrydaily.com/images/ENG_EuroProp_TP400-D6_Test_lg.jpg
.
>>Ric:
>>The wingtips … ought to cause enough frictional heating
By definition, windelecs are unpowered, passive devices; so they can only take energy out of the atmosphere, not visa versa. The speed of the blade tips is caused by the wind itself.
.
@Matt
“it seems to me that having 6 or even 12 blades would allow you to capture more energy from the passing wind that you miss only having three. Just look at any old pump windmill used by ranchers and farmers and they have 20 blades.”
It’s a complicated issue with respect to all the details.
1) Slowing down air to a standstill at the turbine’s rotor plane is completely counter-productive. Which is rather easy to understand because if the wind passing the rotor plane would come to a standstill the rotor would not ‘see’ any wind at all. Thus the wind’s kinetic energy can be harvested only partially:
http://en.wikipedia.org/wiki/Betz%27_law
2) Turbine blades do not work like kites ‘deflecting’ the wind but like glider airfoils. You will probably never see a biplaned glider because the most efficient glider airfoils are slender, high-speed, low-friction/turbulence designs (turbine blades are big and their tips are indeed moving fast).
Now imagine a parcel of air passing the rotor plane. Adding more blades to the rotor would mean cutting through this parcel more often, slowing it down each time (depending on the velocity of the parcel as well, og course). But slowing it down too much willl result in lower efficiency (see 1.) thus adding more blades might actually reduce efficiency while still adding costs. Under favourite wind conditions, two or even a single high-speed blade can perform even better than three (at least in theory – in practice unbalances, resonance and material stress become very serious issues). Therefore the danish three-blade design is a very good general-purpose compromise.
HTH. I’m well aware this just sort of scatches the surface a bit and so should you.
Wolfgang
So if the wind is blowing it keeps the frost down and the wind turbines turning, and as the wind turbine turns it creates wind to keep the potential of frost down?
Why don’t I see any difference between having and not having wind turbines?
Paul Bahlin says:
October 5, 2010 at 4:39 pm
There’s never a free lunch, right? Since the entire planet is basically a solar powered biosphere, it would seem that extracting significant amounts of energy from it to create electricity, has to have an impact in the energy budget. If you get enough of these things spinning there will be an impact that nobody has thought of yet.
One effect I have considered is that much like turning on the AC in your car will create a load on the engine, how much of a load are we putting on the earth? since these are anchored in at some point we would likely add enough resistance to affect Earths rotation. Now as to how much wind resisance that would be (could be a number of windmills that we cant even generate) I have not calculated as I dont even know where to begin the math.
stevengoddard says:
October 5, 2010 at 4:08 pm
Wind farms are causing dangerous climate change. My model says that wind farms in Texas cause more floods in Pakistan.
A definite aplication of the Butterfly Effect.
Standby for the unintended consequences from massive wind farms.
I can see negative effects from the turbine wind turbulence increasing surface evaporation of water from the soil and being detrimental to plant growth.
The frosts in spring also serve to kill early weeds and control insect pests.
“The impacts of wind farms on local weather can be minimized by changing rotor design or by siting wind farms in regions with high natural turbulence. ”
What are these guys proposing then? Adding another counter-clockwise turning rotor for the benefit of a little rime beneath now and then?
And why would s/o prefer turbulent sites? Here in Germany manufacturers are contemplating hub heights of 120… 140m just to escape unfavourable turbulent conditions. Makes no sense to me at all.
Wind Farms will be next to Solar Power which can support mankind. With better designs and good understanding, we can make the best out of this resource
Hey, Ralph, can you add a distinguishing moniker to ‘Ralph’?
Barry is wrong in suggesting that wind turbines will cause cooling by taking energy from the air. They are converting the kinetic energy in the flowing air into a rotational movement. They are less than 50% efficient in this regard and much of the energy is wasted in frictional loss in the hub and gear train and in creating turbulence. The turbulence dissipates in noise which can travel a very long distance and in heating of the local air through friction. I’m sure it’s true though that the major effect on local temperatures is due to downstream mixing of ground level air with higher level air. This would seem self-evident from first principles.
As for their harm, forget bats and birds and give some thoughts for the poor humans forced to live within 2km of these things. They seriously disrupt sleep and ruin health.
Wind turbines are about as useful as garden gnomes in reducing CO2 emissions and Swamykant is either deluded or works for the wind industry. Their sole purpose is the harvesting of subsidies. Apart from green idolatry, why are these ugly monstrosities foisted upon us? As someone is bound to say: “Follow the money”
Stupid me!
Here I thought planetary rotation generated wind and the shape of the planet regulated where the directions of the wind were dominate.
Swamykant says:
October 6, 2010 at 4:09 am
Wind Farms will be next to Solar Power which can support mankind. With better designs and good understanding, we can make the best out of this resource
How does the usable energy produced by wind farms compare to the energy required to smelt the steel for the towers that support the turbines?
Never mind the amount of energy needed to extract the ore used in steel production.
Wind turbines dont have to be so ugly – I know it is a subjective thing but I think this is quite attractive:
There are a number of designs for vertical axis wind turbines but I have no idea how they compare with conventional designs for efficiency, but they do not need a wind vane design as they are omni-directional.
Not only do they affect local weather but they also affect local Doppler Radar. There are a couple of wind farms in neighboring counties and they are picked up on radar. I believe that the image that doesn’t show the interference may be due to the radar not seeing close enough to the ground, it is afterall coming from about 75 miles. Those blips are there 24/7 rain or shine and they do slightly shift around a bit.
Interference
No Interference
*mods, can you fix the links if they aren’t correct?
[Reply: No info contained in 2nd link. ~dbs]
More stuff on wind farms since I nearly live in a 4000 wind mill farm.
1. There are no crops immediately near the wind farm, because during the summer months the wind is too fierce to grow, plow, or to spray plants. So using windmills to help crops is goofy unless we are discussing little tiny home windmills and not the big industrial type.
2. Wind farms are beautiful, many people stop their cars and take pictures of these beautiful machines. Cyclist like to ride the roads near them, very beautiful.
3. I still haven’t been able to figure out why there can be 100 windmills not spinning, during no wind, and yet there will be one wind mill in the lot going like crazy — weirdest thing.
4. Wind is EXTREMELY inconsistent seasonally – there are no economically viable battery back up systems that will outlast a 4-6 month period of no significant wind, there must be an entire energy production system built to compensate for off season demand, which by definition in my way of thinking means, Wind is only a partial answer and will not save money as it’s cost will be additive to a year around system that must be built at 100% capacity anyways.
5. So far I have not seen any windmills self destruct, but it is obvious a few of them have as scraps of windmill metal litter the landscape on some hills around here. So I think it is probably a bad idea to co-locate big industrial windmills and homes and businesses.
6. Birds do not like 50 and 60 mph hour winds especially when they can fly 5 miles away and live at a more reasonable air speeds. The Altamont wind farm is a located in a sort of wind funnel between the San Francisco Bay and the San Joaquin Valley. In my opinion, Bird killing is way over stated by researchers with an incentive to overstate it. Birds do like the windmills during periods of no wind as they make great perches.
7. Ironically, the next county over is working on approving a big fossil fuel power plant just North of the wind farm. They like the placement there because they only consider the environmental impact in their county. Well the wind during 6 months of the year blows hard and directly into my county less than 1 mile away – thus no environmental impact. 🙂 ah politics. While, as I stated before, the wind farm is losing turbines every year due to maintenance issues and they are not being replaced – partly due to environmentalist freaking out about the bird kills and threatening lawsuits and getting settlements and research studies.
So get this, we have environmentalist pushing wind, wind farm is built, wind farm probably kills a few kill birds, other environmentalist sue raising the cost of the wind farm, wind farm is slowing dying, new fossil fuel plant is built. Think how much money, effort, lawsuits, papers, etc. was wasted in a process that just resulting in us doing what we always do.
Dr. John M. Ware says:
October 5, 2010 at 3:45 pm
“Is it still true that wind farms kill many birds?”
Yes, the rotating blades do but the fish are safe from the same fate for now because wind farms keep sea-levels down.
😉
The way bats die due to wind turbines is a completely different mechanism from that of birds. Their lungs explode due to a pressure drop, similarly to the way a divers’ lungs would if he returned to the surface too quickly. Their echo location allows them to avoid actual collision with the blades, but to no avail.
For a lot more information go here…
http://ontariowindperformance.wordpress.com/2010/09/14/table-of-contents/
In Ontario night time performance on average (or on the median) is no better — or worse than day time. Over a year the performance is pretty much level. This may be different in other areas I realize.
Production goes up on the front, and during a large “weather/storm” system and drops for a day or two after.
Read “Powering Ontario” to start if you want an overview of the production — then you can go through the detail data to your hearts content. Ontario has over 625 turbines and about 1,200MW on tap. However, the production is spotty at best. On occasion there is zero production. On many occasions they produce less than 5% of nameplate power.
All of the articles use the original production source data. That makes it difficult for anyone to dispute the data. So far we have had no successful challenges of the findings. As far as I know there is no similar assessment of any other wind power system.
For Medical Issues — just google Wind Concerns Ontario. They are holding a conference on Medical issues this October.
Cheers!
To read how the Ontario government is shoving these industrialized wind facilities down the throats of rural residents, please visit:
http://windconcernsontario.org
Indeed!, local people get angry hot with them.
Current so called wind turbines are useless for a multitude of well researched and published reasons.
Basically they are very inefficient at capturing wind energy, have expensive and heavy gearboxes and really ordenary generators. Engineers are asked to design them to a capacity/price demand, so thats what they do
Some of the discussion here ignores well known differences between prop planes and jets. Ask yourself which is the more efficient.
Seriously, they suck energy out from the wind, changing its kinetic energy into electricity, which deprives it from heat during the day while irradiating friction heat during the night.
Some folks in the windmill industry and their eco-cronies just don’t want to hear that windmills kill birds, many of them protected species:
click1
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click8 [check out the comments]
The value of the energy taken out of the wind is always less than the value of that energy left in the wind to regulate weather and climate. There is a large class of people living downwind from any such rape of Mother Gaia.
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I read recently (sorry, no source – so this is kind of hearsay) that the number of birds and bats killed by buildings, vehicles and such make kills by windmills, even at the most “optimistic” levels of wind usage, rather inconsequential – I would suspect that the windmill kills are also more concentrated, making the situation seem like more of a problem than it is.
That being said, wind stil has technological problems and should not be rolled out en mass by force of government funding.
Chris H @4:48 says im wrong about windmills removing energy from the air thus reducing the temperature. Indeed, if I’m wrong about that then what we have is perpetual motion machine producing more energy than it uses. Yes there can be some localised effects along the blade that do warm up a small amount of air but the net effect is reduction of temperature unless some change of state occurs like precipitation. All the inefficiencies end up returning their heat back to the atmosphere nut the energy that comes out of the generator is the loss the air has undergone. Is is as simple as that.
Barry
Joe Lalonde says:
October 6, 2010 at 5:06 am
Stupid me!
Here I thought planetary rotation generated wind and the shape of the planet regulated where the directions of the wind were dominate.
~ ~ ~ ~ ~ ~
Stupid me!
Here I thought unequal heating of the atmosphere and pressure gradients generated wind.
Seriously, the atmosphere is coupled to the surface by friction and gravity. At the Equator, Earth’s surface moves at about 1,037.5 m/h (1669.8 km/h) and from a view over the N. Pole that movement is counterclockwise. Wind along the Equator is generally clockwise, ignoring the time when there is no wind.
I’m not sure what Joe L. was responding to so maybe this doesn’t help. Sorry if that’s the case.
@WillR
This is excellent backup material indeed. Thank you.
The results are not much different for Germany. Btw my conclusion with respect to demand and wind power output was that one can probably substitute 5…10% conventional power by wind power w/o placing additional burden to the grid and production. Beyond there will be steep increases in demand for long distance transmission capacity (peak export).
These theoretical estimates are well backed up by our situation here in Germany so I place some confidence in my conclusions. We have around 8% substitution currently and desperate needs for long distance transmission capacity has evolved. Severe bottleneck management began around 7% which of course simply means throwing farms off the grid when wind conditions become too favourable with respect to demand. Thus increasingly frequent we pay please-don’t-feed-in-renewables compensations while european power exchange markets are trading negative electricity prices to get rid of the surplus.
The notion that wind farms locally increase convection seems rather obvious and quite trivial. Wind power is truly only useful well away from the electrical grid in areas where solar power isn’t useful. However, the problems wind turbines face in extreme cold would remain.
Ah! slap upside the head, being a dumkopf here. Of course bats don’t fly that high up, and more to the point, bats very unlikely to go anywhere near them, set as they are in open spaces. For echo location bats need a continuous run of things at their level, where insects fly, which in rural locations will be in typical hedged field systems as in England. Where there are gaps in these the bats stop feeding and move away because their echo system has nothing to bounce back from.
In some areas where there have been long strips of hedging taken out they are now putting them back, even to making ‘dummy’ trees to fill the gaps until the natural can grow back as they need a continuous run to cross open fields ,they stick to the edges. Their echo location can only work to a certain distance, where they perceive too much space they won’t fly.
Generalizing: Any energy taken from the environment cools down the environment.
In other WUWT posts we have discussed, also, the not a small problem of the low frequency vibrations effects on people living around, and that’s pollution!
A hundred of these monstrosities, with thousand moving parts can be replaced by only ONE one hundred megawatt of one single moving part. Obviously it is the most intelligent choice that liberals can possibly make.
In a few years its oxidized remnants will remember us the limitless stupidity that men only by chrematistic interests may reach.
Radar issues. Add that on to the cost of wind power.
“Spinning wind turbine blades create a “cone of silence” above the turbines, making it difficult for 2-D radar systems to see aircraft as they fly overhead. It can also create false positives on radar that can look like weather systems (photo). According to Gary Seifert of the Idaho National Laboratory speaking at the RETECH conference in Washington, close to 10,000 MW of wind power has been held up or abandoned completely because of conflicts with FAA, DoD or Department of Homeland Security radar system concerns.”
http://spectrum.ieee.org/energywise/green-tech/wind/wind-turbines-cause-radar-cone-of-silence
Enginear,
the energy you talk about comes from accelerating or slowing down the earth rotation. Winds from the west accelerate, winds from the east slow down.
In Europe, apparently, one can get subsidies for 25 years even though the operational life span of something spinning in the wind is statistically said to last for 20 years. Yet they all seem to be dismantling all those spinning in the wind stuff when those’ve full filled their economic cost return at about 15 years time.
It’s very much like the positive propaganda for windy hardware, what with their use of installed capacity rather then effective capacity right, and with the life span for wind power this converts to, apparently all very logical, a subsidy life span of 25 years for a physical life span of 20 years that’ll self die at the economical life span of 15 years. And for some reason this makes perfectly sense to the eurocrats under our, more or less, self appointed president.
As there are probably hundreds of thousands of tall towers already strung across the landscape carrying electric current from power stations why not stick mini windmills on top of each one of these and feed the wind generated electricity directly into the cables ? Cut out a lot of middlemen that way !!
mhpol says: October 5, 2010 at 9:02 pm
Smokey says: October 6, 2010 at 7:33 am
OK what is the real picture? Smokey I appreciate your pics but what are the figures? Are these gadgets a threat to whole species, or can the populations keep up? Are deaths worse than on the roads?
Now I have a theory. It’s not going to solve the energy challenge but I want windmills as an attraction rather than a menace, if you gotta have some. Nobody ever complained about windmills in Holland. So what is the difference? How can we build beauty? it has to be possible…
The big issues are humanity of scale, and proportion. Each community had a miller who ground everyone’s corn when they needed it… when the wind was blowing, didn’t matter if it was intermittent… only during the day, silence at night. The windmill with its miller was a part of the community, just like the church or the town hall. The technics needed was bound to be seen as beautiful, with just a few windmills locally, not a battery of them for someone else’s electricity. Are broad sails safer for birds and bats? Did they turn slower? Somehow they do look nicer. Are there bird-bat-sensitive current designs? Was the old beauty unavoidably linked to wooden construction?
OK so wooden technology won’t power up electricity. We need metal. So what about those little local windmills I used to see lots of, with about 16 blades on a ring up a little mast… lots of room to develop beauty… just as did the first cars and steam engines and every single one of Brunel’s designs… again it’s scale, building community, and something in each that has character. Well, why not have FIVE blades? The pentagram reveals the Golden Section, and people do pick up on fivefold symmetry as harmonious. Think of all those car hubs with lots of starry designs. Why not do windmills in a similar way, lots of pattern variations within the constraints of workability?
Electricity pylons have a certain beauty which can work… if the landscape still has some rugged features. People want countryside that’s not dominated by metal constructions. Skyline has to be beautiful because it’s seen for such a distance, and because we still know it touches Heaven. Harmonious roof forms make all the difference.
Looks like we need a new architectural canon, that echoes the proportions of sun moon and stars… as did all the beauty of antiquity… and feels right when we trust our higher senses to be intuitively responsive to current challenges, both technical, environmental, economic, political, aesthetic, and ethical.
Ah, it all goes back to integrity… starting with oneself.
Lucy – re: birds, IMO the issue is siting of the turbines relative to habitats and migration paths. Ridge based to capture updrafting wind may coincide with soaring birds of prey, estuary based for smooth fetch, over water wind may coincide with migration paths etc. I believe the RSPB have done a lot of work on these issues.
re: design – most machines are designed according to sound engineering and aerodynamic principles with a particular wind regime in mind. Rotors are generally more solid for smaller diameter slower speed, higher torque operations like water pumping and large diameter low solidity with faster peripheral speeds and larger swept area for electrical generation.
If you want a starting point for good quality info. backed by much real world experience I’d suggest Hugh Piggott’s website “Scoraig Wind Electric”. A good overview presentation of grid scale generation technology, which rightly emphasises the wind regime, is here:
http://www.clemson.edu/scies/wind/Poster-Schmidt.pdf
btw – it is also worth getting a feel for the scale of the energy and power densities associated with renewables relative to those of thermal technology. Check out the sums on the amount of power flow through the high tension grid pylons you mention. David MacKay FRS has a good online book “Sustainable Energy without the hot air”:
http://www.withouthotair.com/
Pete Hayes says:
October 5, 2010 at 9:14 pm
CRS, Dr.P.H
Thanks for that video. I have never read or heard of that type of pollution. How irritating must that be to the occupants.
====
Pete, you are most welcome! These wind farms are becoming a blight in Illinois, and the unintended consequences of any alternative energy source are usually bad.
I’ve been in this game for a long time, e.g. ethanol, biogas etc. Entropy always wins.
I just returned from a vacation in Wyoming and Montana, where I saw a number of windfarms (for example, just north of Cheyenne). The curious thing is that I did not see any transmission lines to take away the power that was supposedly generated. I’m wondering if the power lines are buried, or if this is all for show? In every case, I saw one or two of the group whose blades were not moving.
NY Times has an interesting story:
http://www.nytimes.com/2010/10/06/business/energy-environment/06noise.html
VINALHAVEN, Me. — Like nearly all of the residents on this island in Penobscot Bay, Art Lindgren and his wife, Cheryl, celebrated the arrival of three giant wind turbines late last year. That was before they were turned on.
“In the first 10 minutes, our jaws dropped to the ground,” Mr. Lindgren said. “Nobody in the area could believe it. They were so loud.”
Lucy,
I was replying to the assertion: “Bird killing is way over stated by researchers with an incentive to overstate it.”
Sorry I didn’t make that clear.
RE: bubbagyro: (October 5, 2010 at 6:59 pm)
“Windmills are much more efficient bat-swatters than Granny with a tennis racquet.
I suspect that a serious bat depopulation problem might result in a requirement that all these windmills must warn the animals away with built-in noise sources producing loud irritating sounds at the most sensitive point in the bats hearing range. This might be effective with birds as well.