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
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
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!
.
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.
.
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…
.
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