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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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.
Will they also count the bird and bat bodies that pile up in the “wake”?
“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.
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.
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
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.
Here’s a better picture of turbine wake –
ttp://i54.tinypic.com/jqpa9u.jpg
http://i54.tinypic.com/jqpa9u.jpg
works better.
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.
“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.
Judging by the turbine wake pictures, I’d be more than a little concerned about the effects on shipping!!
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.
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.
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.
What I’d really like to see for our Alberta wind farms is simply a (post-funeral) wake☺ … and the sooner the better.
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)
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.
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.
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.
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.
“but the atmosphere is different, it’s more variable and complicated.”
But the Earth’s climate is predictable?
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