Wakey wakey

CU-Boulder leading study of wind turbine wakes

A turbine at the National Wind Technology Center south of Boulder, Colo. (photo courtesy of CIRES)

While wind turbines primarily are a source of renewable energy, they also produce wakes of invisible ripples that can affect the atmosphere and influence wind turbines downstream — an issue being researched in a newly launched study led by the University of Colorado Boulder’s Julie Lundquist, assistant professor in the atmospheric and oceanic sciences department.

The study, called the Turbine Wake and Inflow Characterization Study, or TWICS, also includes researchers from the National Oceanic and Atmospheric Administration, the U.S. Department of Energy’s National Renewable Energy Laboratory, or NREL, and the Lawrence Livermore National Laboratory in Livermore, Calif.

Scientists and wind energy developers will use results of the study to better understand power production and increase the productivity of wind farms, according to the researchers.

“Today’s massive wind turbines stretch into a complicated part of the atmosphere,” said Lundquist, who also is a joint appointee at NREL. “If we can understand how gusts and rapid changes in wind direction affect turbine operations and how turbine wakes behave, we can improve design standards, increase efficiency and reduce the cost of energy.”

To measure wind shifts and wake behavior, the researchers will monitor a wind turbine at NREL’s National Wind Technology Center in south Boulder, using an instrument developed at NOAA called a high-resolution scanning Doppler lidar. The lidar produces three-dimensional portraits of atmospheric activity and can capture a wedge of air up to 3,280 feet from the ground and 4.3 miles long.

Robert Banta, an atmospheric scientist with NOAA’s Earth System Research Laboratory and a TWICS researcher, has worked with the instrument for several years.

“The wake effect has been modeled in wind tunnel studies and numerical models,” said Banta, “but the atmosphere is different, it’s more variable and complicated.”

Researchers also will use a specialized laser called a Windcube lidar and a sonic detection and ranging system, called a Triton sodar, to measure wind and turbulence. In addition, NREL has installed two meteorological towers, each 135 meters tall, which will be used to measure air temperature, as well as wind and turbulence.

“Even fluctuations in air temperature throughout the day can affect wind turbine wakes,” said Lundquist. “The resulting changes in wake behavior can impact the productivity of wind farms with many rows of turbines, so it’s important to observe them in detail and understand how to minimize their impacts.”

Other TWICS researchers include Yelena Pichugina, Alan Brewer, Dave Brown, Raul Alvarez and Scott Sandberg of NOAA, Neil Kelley and Andrew Clifton of NREL and Jeff Mirocha of Lawrence Livermore National Laboratory.

CU-Boulder graduate students Matt Aitken, Mike Rhodes, Robert Marshall and Brian Vanderwende of Lundquist’s research group also will work on the study.

For more information on the TWICS study and Lundquist’s research visit atoc.colorado.edu/~jlundqui/re.html.

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Ed Barbar

I think slowing down the air with wind power is a bad idea. It will make the air more stagnant, prevent evaporation, and heat up the atmosphere.
Also, imagine the “wind wars” that might ensue. Imagine if Canadians stop the polar streams from hitting the US. Major heating here in the US.
Just say “No” to any form of energy. It’s not natural.

Brian H

Will they also count the bird and bat bodies that pile up in the “wake”?

jorgekafkazar

“Today’s massive wind turbines stretch into a complicated part of the atmosphere,” said Lundquist.
That implies there is an uncomplicated part of the atmosphere.
Brian H says: “Will they also count the bird and bat bodies that pile up in the “wake”?
The bodies don’t make it that far, having pretty much splattered the blades and the soil beneath.

RiHo08

Wind wakes for airplanes is particularly important when large “jumbo” jets leave a very turbulent wake. This is relevant for subsequent aircraft landing or taking off on the same runway in that wake. The turbulence maybe so severe that rudders have broken off aircraft as may have happened in NYC several years ago.
Multiple wind turbines on a “wind farm” may overlap turbulent airflow leaving airstream distortions for miles. With land based wind farms, there may be much more impacts locally than maybe those turbines located off shore. Yet another study to contemplate. But then we would have to know & put equations to a baseline impact of wind on surface water. My understanding is that we don’t have such equations nor understandings.

Latitude

good grief….
How about making them work first……………………

Wind farms are a very dilute and unreliable method of generation. They are a fad now but have no long term future other than a source of energy for very small communities in remote locations. The bigger the turbines are the harder they are to service. The stronger the wind, the faster they wear out.
lots of info here
http://www.palmerston-north.info

John F. Hultquist

Sutton claims not to have said he robbed banks “because that’s where the money is” :
http://en.wikipedia.org/wiki/Willie_Sutton
. . . still, an urban legend can be useful. Namely, would it not be wiser to study wind energy in places where there are such entities in large number, various configurations, topography, and other variables?
Then too, wind energy needs a storage system, without which it is next to useless.
Personally, I prefer approximate answers to important questions rather than exact answers to questions of little interest.

Mike McMillan

Here’s a better picture of turbine wake –
ttp://i54.tinypic.com/jqpa9u.jpg

Mike McMillan
WTF

Slightly OT but still related…not only are these things modifying wind patterns but I suspect grid voltage patterns and amplitude also.
Has anyone else out there seen a spike in electronics blowing or malfunctioning for no particular reason? I have had several VFDs and voltage sensing control boards go in the last year or so and can not pin point the problem. I suspect that the inverters and syncronizers being used here in Ontario to integrate the wind and solar are the problem. I can’t prove it yet but I have anecdotal evidence which seems to be building. I would appreciate any comments.
If you think this is too far off topic Anthony feel free to snip or move.

Mike Bromley

“The wake effect has been modeled in wind tunnel studies and numerical models,” said Banta, “but the atmosphere is different, it’s more variable and complicated”
Let’s hear the second part again:
“but the atmosphere is different, it’s more variable and complicated”
Maybe this erudite spokesperson should go play some hockey with the big kids at CRU, or just use one of their GCM’s to instantly predict when wind turbines will reach peak efficiency. Heck, just ask Dr. Jim, and save a bundle.

DJ

Judging by the turbine wake pictures, I’d be more than a little concerned about the effects on shipping!!

Andy G55

It always seemed very odd to me that these huge inefficient structures could have ever become the “poster child” for green energy.
How does it go.. “forgive them lord, for they know not what they do”.

There’s wind wake data going back decades. These guys need to do a proper library search for the old textbooks. I have a suspicion that the research team is either trying to reinvent the wheel or doctor the numbers down to favour claims of a greater possible density to fit the plans of a particular climate change related case. The lidar should just confirm the old work part of which was done by the Wright brothers. The turbulence can be adjusted anyway by adding a wide conical base to the tower up the first 3 meters. Trees and berms can shape the flows if placed properly. There are also venturi tower and ducted wind mill designs that negate the turbulence. A venturi tower has a poly-directional venturi at the top of a tower with the ducted mill at the base of the tower. Air is sucked up the tower coming in though the turbine at the base. Like many of the best designs the patent expired in the 1980’s so no one’s using it?!?
If the wind industry had gone for pumped water and not electricity they could have used windmills like the Dutch sail or Darrieus wind turbine. These work at very low winds speeds, have reduced turbulence and stores energy. With water pumped up hill you have on demand electricity via a micro hydro technology. This eliminates intermittent energy output but requires more planning and more land. The green movement hates dams and as a result the direct technology got all the government, green NGO and IPCC backing. The industry has thus backed direct electric drive, thinking that that could be made cheaper, but its proving inadequate.

oMan

Wesley Bruce: those are some very helpful perspectives. I need to go look at what you describe (venturi towers, ducted windmills). As for pumping water uphill to store the wind energy, sure. I would love to see numbers on how much water you’d have to shift how far upward (water towers? lakes?) in order to get adequate storage for “real world” needs. One idea that occurred to me is using weights. You might have a big concrete weight on a wire suspended in a shaft, or a rack of concrete weights on wires in a “farm” comprised of the acreage around the base of the wind farm. When the wind starts to blow, the weights get winched upward one by one. When you want the power, they descend and run the generator. Haven’t run the numbers on how many weights, how high, how expensive, etc. Increasingly I’m skeptical that wind will ever be a mass power source. We will end up with all these rotting eyesores on some of the most beautiful ridges and valleys around. Oh well, live and learn.

R. Shearer

If I climb onto the top of my roof, I can see a few of those turbine blades at NREL’s site some 7 or 8 miles away. They are impressive to gaze upon. What keeps the hundred or more NREL employees busy that oversee wind research there, I have some idea that the tax payer is not getting full benefit. Do we really need the U.S. government to do what GE, Vestas, etc. could do themselves?
My work sometimes takes me to NREL sites. When I arrived for one of my meetings, a group of perhaps ten administrative assistants was setting up a “Candy Land” game in a couple of hallways. I don’t know what that was all about, but when I left about 2 hours later, they were still at it. I guess they were having fun. By the way, usually NREL’s wind turbines are idled. Ironic.

Clive

What I’d really like to see for our Alberta wind farms is simply a (post-funeral) wake☺ … and the sooner the better.

Eric Larson

One more factor is the evaporation down-stream of the turbine. Farmers are finding a greater moisture loss because of the turbulence created at the surface. In areas such as Eastern Oregon where they plant a wheat crop one year and conserve water the next, they are loosing the wheat crop in the downstream cone of turbulence. This may aalso be happening in the midwest corn fields. (corn takes more moisture)

philincalifornia

R. Shearer says:
April 26, 2011 at 7:43 pm
My work sometimes takes me to NREL sites. When I arrived for one of my meetings, a group of perhaps ten administrative assistants was setting up a “Candy Land” game in a couple of hallways. I don’t know what that was all about, but when I left about 2 hours later, they were still at it. I guess they were having fun. By the way, usually NREL’s wind turbines are idled. Ironic.
—————————————–
Betcha they tell their Moms and Grans that they have meaningful lives though, and that they’re scientists.

I was on the periphery of a study of this at the Boundary Layer wind tunnel at UWO in 1977. The results were that wind turbines should not be spaced closer downwind from another turbine at less than 28 diameters of the turbine size. Turbines in a line perpendicular to the prevailing winds, no problem, in a matrix, big problem.

Common Sense

This site is a few miles up the road from my house in Arvada, I drive by them all the time. They are HUGE and I would never want to see “farms” of them, talk about polluting the view!
They are so big that I can actually see them turning from my office window 30 miles south, on a clear day.
The funny thing is that they can only run them with winds between 10 and 45 mph and our winds in the foothills (Golden and Boulder are notorious for wind damage) frequently gust double that. Because of La Nina, we’ve had a very windy, dry winter. During our last wind event, we had gusts of 86 mph. Even sustained winds are frequently higher than that. I’m guessing that they’re not operating about 50% of the time, very efficient.

Jimmy Haigh

I’ll make a prediction that sometime before too very long – within the lifetimes of many here – all these windfarms will simply fall into disrepair. The money it will take to replace them will be more that the money they earn as energy producers.

Cementafriend

I agree with the comments saying that goernment funded universities and research organisations should not be waste time and effort on wind turbines and wind farms. If manufacturers want to fund research either sourced or in house that is their commercial decision but they should not be especially subsidised. Funding for research on real future energy (small and large scale) like Thorium reactors is much more appropiate for universities and government research establishments. Cheap energy, medical intrumentation, medical radiation isotopes, farm produce sterilisation etc are some of the benefits of nuclear research. There are no benefits in studying windmills which have had various commercial uses for over a thousand years but have never assumed an important part (ie large portion) of energy supply.

JinOH

“but the atmosphere is different, it’s more variable and complicated.”
But the Earth’s climate is predictable?

AndrewSanDiego

They could probably save a lot of taxpayer dollars by going over to CU’s Aerospace Engineering department and asking an old aerodynamics professor what he knows about wake turbulence behind moving wings.
But that won’t happen for two reasons:
1. It’s about SPENDING taxpayer dollars, not saving them…
2. The engineering professor is probably a skeptic of CAGW, and is therefor blacklisted from receiving funding from NOAA

John McDonald

Sounds like this is just another government funded researcher milking the tax payer. We’ve got a few of those government funded PhDs in the Altamont Wind Farm. In my opinion: Dr. Smallwood is getting a few hundred thousand dollars a year to count phantom dead birds and burrowing owls that magically die during the periods of no wind.

philincalifornia

Jimmy Haigh says:
April 26, 2011 at 9:00 pm
I’ll make a prediction that sometime before too very long – within the lifetimes of many here – all these windfarms will simply fall into disrepair. The money it will take to replace them will be more that the money they earn as energy producers.
————————————————————————
….. and that a business could be made picking up those pieces of sh*t and selling them for scrap.
Betcha the people who put them there are all ready to profit from their demolition.

SSam

oMan says:
April 26, 2011 at 7:27 pm
“… As for pumping water uphill to store the wind energy, sure. I would love to see numbers on how much water you’d have to shift how far upward (water towers? lakes?) in order to get adequate storage for “real world” needs…”
Look no further than peaking reservoirs.
http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity
Of course, you do have to keep an eye on how much water you pump up to the top of the mountain. An insta-flood could be an issue.
http://en.wikipedia.org/wiki/Taum_Sauk_Hydroelectric_Power_Station
And, if you have Google, here is another: Rawlins Peaking Reservoir – Wyoming
41.743954° -107.257627°

Robert M

Did he just say that the real world was different then the computer models? Gasp! Say it ain’t so!
Not sarcastic, just tired of all the bull. The stupid climate models are why the stupid windmills are there in the first place, those seem to be good enough…

dp

What won’t people do to get hooked up to a government teat?

brc

I’m no aerodynamics expert but it seems quite simple to me that if you harvest energy from the wind, somewhere that has to have an effect. Just going from the ‘energy cannot be created or destroyed’ that every kid learns. The more energy harvested, the greater the effect. Same goes for solar panels – it’s got to have an effect somewhere, even if they are horribly inefficient.

wayne

They are worried of downwind turbine efficiency and I too am worried of evaporation, as some above already. Sure hope they are measuring it also, along with a far removed standard to compare against.
If downwind evaporation is greater than normal then there is probably no global problem but to the local plant life and farmers. If downwind evaporation is markedly less than normal without the windmills we may have a continental scale problem brewing as they blanket the hillsides and coasts.
See my logic? What will a continent be like with a sizable decrease in total evaporation flowing across it? I am not knowledgable enough to answer that, how many miles downstream does it extend, hope someone else is questioning.

kuhnkat

OK, so they spend a few million to improve the efficiency of the turbines by as much as 10%. This means the turbines are STILL not useful for baseload generation. Are these people really that ignorant or are they just doing it to make the money from the gubmint grants…

Latimer Alder

Anthony
I hate to disagree with you but you state:
wind turbines primarily are a source of renewable energy
IMO modern day windmills (they are not turbines) are primarily sacred objects of worship so that the Chosen People of the Green Cult can visibly demonstrate their love of the Gaia Goddess and so gain redemption for their energy-grubbing sins.
By building higher and bigger- like the mediaeval cathederal builders – they show evermore their devotion and distinguish themselves from the rest of humanity. Like cathedrals (and castles) they are built on hilltops so all the surrounding peasantry can see their subjugation to The Word.
That these symbolic idols occasionally produce some spare energy is only of secondary importance to the Cultisists. It is not reliable, efficient or predictable enough to be useful for many real applications.
But that hardly matters. The point is made. The sight of these ‘magnificent erections’ are testament to the ego and sanctanimity of the Cult. Look upon their works and tremble.
REPLY: You aren’t disagreeing with me, but with the press release. – Anthony

Willis Eschenbach

When I used to teach windmill construction to the Peace Corps Volunteers and their local counterparts, I used to use streams of soap bubbles to visualize the air currents and how they flow around buildings, walls, and trees. I’d love to see a lidar or a “sodar” image, never even heard of the latter …
Interesting find,
w.

gerard

I was reading New Scientist today and I thought the article which can be found at the following link might be of interest
http://www.newscientist.com/article/mg21028063.300-wind-and-wave-farms-could-affect-earths-energy-balance.html?full=true
It is also interesting tha New Scientist had to change the title of the article after complants This article has elicited a considerable amount of interest, and some criticism. We always welcome discussions of the stories we publish. Some readers felt the original headline (Wind and wave energies are not renewable after all) was misleading, so to address these concerns we have changed it. We have also been made aware of a wider debate about Kleidon’s research that we did not address in the original article: we will continue to follow this issue and report back on what we find.

gerard

I was reading New Scientist today and I thought the article which can be found at the following link might be of interest
http://www.newscientist.com/article/mg21028063.300-wind-and-wave-farms-could-affect-earths-energy-balance.html?full=true
It is also interesting tha New Scientist had to change the title of the article after complants

This article has elicited a considerable amount of interest, and some criticism. We always welcome discussions of the stories we publish. Some readers felt the original headline (Wind and wave energies are not renewable after all) was misleading, so to address these concerns we have changed it. We have also been made aware of a wider debate about Kleidon’s research that we did not address in the original article: we will continue to follow this issue and report back on what we find.

RiHo08 says: April 26, 2011 at 6:06 pm
“Multiple wind turbines on a “wind farm” may overlap turbulent airflow leaving airstream distortions for miles.”
Personally I think people have vastly underestimated the environmental damage of windmills and the EPA really ought to be banning these things. It is not simply that the airstream is distorted, in effect a row of turbines is almost as effective as an equivalent rise in land, that will dramatically affect local wind patterns, cause shifts in rain patterns, it will create areas of relatively “still” air in the wake of the turbines with lower evaporation and therefore lower cooling significantly increasing temperatures in that region.
Then we have the regional weather changes. Not only do wind turbines increase the effective height of the land, but they literally slow down the wind. The wind accounts for around 50% of the cooling from the earth’s surface, so on a regional basis windmills are likely to significantly increase temperatures potentially creating more global warming than they are intended to save (even with the mythical 3-5x multipliers to make the real physics seem mildly scary)

Lawrie Ayres

During our past summer South Australia had a four or five day heatwave. Maximun power consumption of nearly 3000 MW occurred at 4.30 one Friday afternoon. SA has 1050 MW of installed wind power but when most needed produced only 49 MW. That I believe sums up windpower. It is seldom available when needed. Cold weather often is accompanied by a stationary high (lots of frosts) and NO wind. Wind is just another feel good waste of money.
The suggestion above to use wind power to drive pumps and store elevated water for later hydro generation has promise. Then again those 25 MW packaged nukes are probably cheaper per MWh and heaps more reliable. We used windmills for stock water in the fifties but had to fit a jack pump belt driven from a tractor when the wind didn’t blow.

Martin Brumby

They’d be better researching how to make the wind blow when we need electricity.

Martin Brumby

@SSam says: April 26, 2011 at 10:28 pm
@oMan says: April 26, 2011 at 7:27 pm
In the UK we have four pumped storage schemes. Ffestiniog and Dinorwig in Wales, Ben Cruachan and Foyers in Scotland. IF all the pumping was done by wind power, they might be considered ‘renewable’.
There is scope for using the sea as a ‘bottom reservoir’
http://www.hitachi.com/rev/1998/revoct98/r4_108.pdf
descibes a scheme in Okinawa, there is at least one scheme proposed in Hawaii.
Eyewateringly expensive but do-able.
I’m also aware of one study examining the potential use of a disused coal mine. Enormous potential pressure to run a turbine in ‘generating’ mode. Very difficult to prevent the residual energy knocking the hell out of the underground workings.

Keith Minto

#
#
brc says:
April 26, 2011 at 10:43 pm
I’m no aerodynamics expert but it seems quite simple to me that if you harvest energy from the wind, somewhere that has to have an effect. Just going from the ‘energy cannot be created or destroyed’ that every kid learns. The more energy harvested, the greater the effect.

Slowing the Earth’s rotation ?

Dave Baker

I’ve never understood why Greenies who are so concerned about small changes to our weather patterns/climate (seems interchangeable to them) don’t consider the so-called ‘butterfly effect: if that butterfly in Brazil can flap its ickle wings and affect the weather half a world away, what will fields of huge wind turbines do?
If wind farms are extracting wind energy (OK, not as much as we’re led to believe)from the air, might that not have consequenses down wind and over time? More ‘extreme weather events’? Oops, only climate change/disruption can do that.

Geoff Sherrington

Mike McMillan shows beautiful photo of turbine wake.
Note that evey windmill is stopped. Imagine the effect if they were rotating! The efficiency of a turbine is enhanced by wind flow that is closer to laminar than turbulent. Here we see turbulence aplenty. It is such poor design to put them in neat rows so that the wake from the front ones spreads to all those in the line behind. At least this image shows that it is going to take many, many turbines to stop the wind and hence stop the earth from rotating. (sarc/off)

Tom in South Jersey

I’ve often wondered whether the windmills will effect weather patterns. Essentially they are removing energy from the atmosphere. The more windmills, the more energy being absorbed out of the atmosphere by the blades in order to generate electricity. Is it not possible that this could in some way effect weather patterns in a manner similar to the urban heat island?

greg holmes

“It all makes work for the working man to do” Flanders & Swan circa 1965

Claude Harvey

Whenever one of our national labs ventures into an “alternate energy study”, hide your tax-paying wallets. In my experience, the money they’ve wasted over the years “studying” geothermal energy, for example, while producing no results beneficial to the industry is staggering. Their typical field project burns massive amounts of money until the money is gone and then everyone goes home with only a minute portion of the stated project objective having been met. As a grizzled old well driller in their employ once told me when one of the labs was attempting a “deep core drilling” project , “These smart folks don’t know the first thing about geothermal well drilling and won’t listen to those who do. It’s a mess.”

Mark Gibbas

From the point of view of doing science, I have no problem with this study. But I have a slight fear of what the results might be twisted into, for example a position that states harvesting wind energy is bad. If this extreme position is adopted, then we would also need to put a moratorium on any project that effects wind flow including tall buildings and aircraft. As I said, this is a ‘slight’ fear. Beyond that, I think it is a great idea to study the dynamics of wind power as this should help advance the efficiency. And our planet needs every safe source of power production we can develop, and thus wind energy is extremely needed, along with solar, tidal, hydro, and whatever else we can dream up.
Lastly, do NOT believe the hype from people who claim that wind is not cost effective. It is very much cost effective, because once you build the wind farm, the cost to operate it is very low in that you don’t not have to “dig up wind” in order to run the turbines. Since wind is a free and immediately usable resource, there are no ‘supply costs’ in running a wind farm. Comparatively, fuel based power generation (gas, coal, nuclear) have substantial and continuous fuel costs that over the life time of the plant dwarf the costs of ‘free’ power such as wind.

starzmom

I once worked on a proposed pumped hydro storage project. The lower reservoir would have been excavated out below an old iron mine. The existing mine structure was not suitable. The upper reservoir would have been a pond remaining from the mine days. Very interesting project, but the economics weren’t there, and I don’t think it was ever built.

DirkH

oMan says:
April 26, 2011 at 7:27 pm
“Wesley Bruce: those are some very helpful perspectives. I need to go look at what you describe (venturi towers, ducted windmills). As for pumping water uphill to store the wind energy, sure. I would love to see numbers on how much water you’d have to shift how far upward (water towers? lakes?) in order to get adequate storage for “real world” needs. One idea that occurred to me is using weights. You might have a big concrete weight on a wire suspended in a shaft, or a rack of concrete weights on wires in a “farm” comprised of the acreage around the base of the wind farm. When the wind starts to blow, the weights get winched upward one by one. When you want the power, they descend and run the generator. Haven’t run the numbers on how many weights, how high, how expensive, etc. ”
The weights work exactly as pumped storage hydro; to store 8 kWh you need 125 tons of weight (or water) in your attic (assuming a two story house). So, it’s a lot of weight you need. That’s why pumped storage hydro reservoirs need to be big.
You find a lot of numbers in MacKay’s online book.
http://www.withouthotair.com/