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.
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h/t to WUWT readers M. White and Scarlet Pumpernickel
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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.
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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.