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
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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.”