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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64 Responses to Wakey wakey

  1. Ed Barbar says:

    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.

  2. Brian H says:

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

  3. jorgekafkazar says:

    “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.

  4. RiHo08 says:

    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.

  5. Latitude says:

    good grief….

    How about making them work first……………………

  6. Zorro says:

    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

  7. John F. Hultquist says:

    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.

  8. Mike McMillan says:

    Here’s a better picture of turbine wake –

    ttp://i54.tinypic.com/jqpa9u.jpg

  9. Mike McMillan says:

    works better.

  10. WTF says:

    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.

  11. Mike Bromley says:

    “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.

  12. DJ says:

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

  13. Andy G55 says:

    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”.

  14. wesley bruce says:

    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.

  15. oMan says:

    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.

  16. R. Shearer says:

    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.

  17. Clive says:

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

  18. Eric Larson says:

    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)

  19. philincalifornia says:

    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.

  20. 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.

  21. Common Sense says:

    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.

  22. Jimmy Haigh says:

    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.

  23. Cementafriend says:

    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.

  24. JinOH says:

    “but the atmosphere is different, it’s more variable and complicated.”

    But the Earth’s climate is predictable?

  25. AndrewSanDiego says:

    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

  26. John McDonald says:

    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.

  27. philincalifornia says:

    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.

  28. SSam says:

    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°

  29. Robert M says:

    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…

  30. dp says:

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

  31. brc says:

    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.

  32. wayne says:

    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.

  33. kuhnkat says:

    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…

  34. Latimer Alder says:

    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

  35. Willis Eschenbach says:

    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.

  36. gerard says:

    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.

  37. gerard says:

    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.
  38. 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)

  39. Lawrie Ayres says:

    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.

  40. Martin Brumby says:

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

  41. Martin Brumby says:

    @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.

  42. Keith Minto says:

    #
    #
    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 ?

  43. Dave Baker says:

    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.

  44. Geoff Sherrington says:

    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)

  45. Tom in South Jersey says:

    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?

  46. greg holmes says:

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

  47. Claude Harvey says:

    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.”

  48. Mark Gibbas says:

    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.

  49. starzmom says:

    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.

  50. DirkH says:

    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/

  51. George E. Smith says:

    Can’t be true; wind turbines only take up about 1/4 of an acre. That’s still a very low power density. I have a compact electric power source that puts out 1.5 MegaWatts per square metre; simply fabulous, and I have several of them in my house. Actually have a bunch of them right at my feet under my desk.
    They are about 4 x 4 cm (0.0016 m^2) and I can get 20 Amps at around 120 Volts out of one. So why would I be interested in wasting a full quarter acre on a wind turbine.

    And now I find out that you actually need more like four miles behind them and a km high.

    How many times have I said on WUWT that a wind turbine is actually a gas turbine engine, with the heat energy being provided by the sun, miles away from the final turbine impeller; and that you need a vast air duct in front of the turbine to bring the working fluid (air) into the turbine fan, and another big exhaust duct to direct the exhaust working fluid out the back. It takes thousands of acres to run a one MegaWatt solar powered atmospheric turbine engine.

    I’ll stick with my compact electric power sources. Somebody claimed that there is some big monster auxilliary component up in the hills somewhere that is wired to my electric power sources; but I’ve never seen it, so what do I care.

    But that solar powered air operated gas turbine generator, is supposed to run for free they say, and doesn’t put out much CO2. They do go ape sometimes; and simply cut themselves down with the propellor run amok.

  52. jon shively says:

    The charter of the NREL is to develop better wind turbines. The bulk of the funds being spent in 2010 were related to the wind turbines.
    One issue against wind farms is they use a lot of land, 22 acres per turbine. Projecting the growth of wind farms in the west to deliver 20% of the electrical energy on the grid, with 2 MW turbines, the estimated square miles of wind turbines is prodigious, hundreds of square miles covered with towers. However, if the turbines were 10 times larger and could be packed in closer so the wake of one turbine does not drastically affect its neighbor, the impact on the demand for space could be reduced. This research could shed light on how high density the packing of wind turbines can be. However, another thrust of NREL is to develop bigger and better turbines mainly for off land use. I can just imagine the 100GW tower and the impact on the aesthetics of western natural beauty. It would have to be put in the bottom of the Grand Canyon to keep airplanes from colliding with it.
    While this research will provide employment, the wind power development community is grasping to hold on to the research support. The problem for NREL is that they are working on the wrong side of the effort to implement wind farms as a source of electrical power. The current technology is not practical because the wind is unpredictable and variable. Consequently, the wind turbines as a source of electricity are also unpredictable and variable. Size doesn’t really matter. Wind technology unlike the grid which has a daily expectation of demand and tries to anticipate peak demand cannot be depended upon to be available at any time let alone at peak demand. The wind farms must have some way to store energy to be practical and most do not have that option available.

  53. George E. Smith says:

    “”””” Mark Gibbas says:
    April 27, 2011 at 6:15 am
    ……………………..
    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………………”””””

    So are you suggesting that “wind” power is NOT “solar” power. So where is all that free wind energy coming from ?

    Why don’t you calculate the Carnot Efficiency of a typical wind power turbine/generator system; and then tell us how you are going to raise that efficiency.

    So how come T. Boone Pickens decided to not invest his inestimable Texas wealth in that free energy from wind? Uually, very wealthy people know a good deal when they see one and jump on it to increase theri wealth. Don’t seem to be many wealthy people in the (free) wind power business.

    So should the Government; as in we the people, charge these investors for their use of our free wind energy supply; or are we just going to let them build their fans anywhere they want to, and then actually charge us fo the free energy they get.

  54. Steve C says:

    Considering the proverbial results of the flapping of a butterfly’s wing on the weather, perhaps we should just be grateful that the effects of the number of these monstrosities already out there have not already triggered climatic apocalypse.

  55. Betapug says:

    There is a much better “iconic image” to go with this post: http://ict-aeolus.eu/images/horns_rev.jpg
    It goes with the caption, “Beatiful Photo Shows Wake Effect of Wind Turbines” from this article from Treehugger: http://www.treehugger.com/files/2010/01/offshore-wind-farm-photo-wake-effect.php (Embedded link in article is broken)
    Makes a nice comparison with the stock water vapour from “smokestacks” image that accompanies all the “carbon polluter” stories.

    The discussion following is interesting for the apparent belief expressed by some that surface level “weather” is not affected by surface level conditions, only upper level. My understanding is the extended wake turbulence produces drying effects for thousands of metres on land with variable consequences for agriculture.

    The effects on non-vegetable living downstream environment are also far greater than we hear. The perpetual bird and bat kills are also not the quick surgical slices or pressure wave organ explosions occasionally mentioned. Many die slow agonizing deaths as this paper from the University of Calgary makes clear: http://ucalgary.academia.edu/erinbaerwald/Papers/182008/Incidence_and_Management_of_Live_and_Injured_Bats_at_Wind_Energy_Facilities

    More Green Jobs here, obviously.

  56. Paul Linsay says:

    George Smith @ 8:44 am

    The numbers I’ve seen are actually 80 acres for a 1.5 MW turbine to prevent turbulent interference between generators. It works out to 4 W/m^2, a very low generating capacity.

  57. feet2thefire says:

    Duh.

    Since the Wright brothers (using the wind tunnel they invented) invented a VERY efficient propeller and they and others developed airfoil wing shapes, the airfoil shape has been recognized (and used) to make efficient use of propellers and fan blades. Centrifugal airfoil industrial fan blades are even up to 91% efficient (Chicago Blower’s, specifically).

    It is obvious that wind turbines use the airfoil shape to get what efficiencies they do.

    But one thing about airfoils is this: The flow MUST be laminar over both the wind side and the lee side of the blade/wing. ANY disturbance of the laminar flow rapidly diminishes the airfoil’s ability to work efficiently – or in some cases, to work at all (as in when a plane stalls at low speed or is caught in wind shear).

    So, though I hadn’t thought about this in this specific regard, the point is obvious. (I DID think of it in terms of ocean current farms, which I think is the greatest untapped energy source on the planet. I don’t have the know-how to figure how close, but ocean turbines, even at only 2-3 knots, can be utilized in repetitive banks (and at different depths, too). I understand ocean currents to be more consistent and aligned than winds, which vary in intensity and direction from moment to moment. Because of this more homogeneous flow, I believe they can be placed fairly close to each other.

    With current velocities of only 2-3 knots, much more force (and thus energy) is available than the 12-knot wind turbines are designed for. I’ve read that flowing water at a given speed has 200 times the applied force of wind. So 2-3 knots may not sound like much, but it still affords more force – and it is force>/i> (aided by efficiencies, of course) that delivers wattage. Plus, fish are not in danger, as fish can simply swim around the blades. And there won’t be any ocean turbines self-destructing, either. – or shutting off because the fluid velocity is too high. They would not be restricted as to depth like wind turbines are with height.

    Banks can be several turbines across, and several deep can be set every few hundred feet, all along the Gulf Stream or any other consistent ocean current. The same technology that currently exists to convey the electrical power to land from wind farms can be utilized for ocean currents.

    Compared to the spacy schemes “green” folks have come up with to create clouds and such, developing this technology would a no-brainer.

    And laminar flow over the airfoil/turbine blades is more guaranteed.

  58. Ed Dahlgren says:

    philincalifornia says:
    April 26, 2011 at 8:40 pm
    R. Shearer says:
    April 26, 2011 at 7:43 pm

    Betcha they tell their Moms and Grans that they have meaningful lives though, and that they’re scientists.

    When you live in paradise (i.e., the Boulder area) you don’t owe nobody no explanations! ;-)

  59. mkelly says:

    Mark Gibbas says:
    April 27, 2011 at 6:15 am
    “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.”

    Bunkum. You failed to mention the need to build a power generation supply equal to whatever the wind is as a backup in case of no wind. And those back up must be kept running so there is no loss of electricity if switch over is needed. So you pay twice.

  60. Z says:

    Brian H says:
    April 26, 2011 at 5:48 pm

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

    No, no – bird migrations into wind farms is a good thing, and this experiment will prove it. They’ll see one big echo from an eagle flying into a turbine blade. Then they’ll see two smaller echos emerging from the far side.

    Those must be baby birds – right?

  61. George E. Smith says:

    “”””” Paul Linsay says:
    April 27, 2011 at 10:53 am
    George Smith @ 8:44 am

    The numbers I’ve seen are actually 80 acres for a 1.5 MW turbine to prevent turbulent interference between generators. It works out to 4 W/m^2, a very low generating capacity. “”””””

    Well that’s sor of the “how close can you mount twin outboard motors on your boat and have them not interfere with each other. ?” question. What I was referring to was how much clear space do you need in front of the turbine to get clean non-turbulent air coming into the turbine, plaus how much more do you need behind the turbine, so it doesn’t generate a lot of back pressure. That’s a lot more than 80 acres.

    The California Altamont Pass wind farm, needs the whole of San Francisco Bay in front of it to duct air into those turbines, and the whole California Central Valley to exhaust the disturbed air behind them.

    Try to get a permit to install a smaller wind turbine on the roof of your house.

  62. Brian H says:

    mkelly says:
    April 27, 2011 at 12:34 pm

    Bunkum. You failed to mention the need to build a power generation supply equal to whatever the wind is as a backup in case of no wind. And those back up must be kept running so there is no loss of electricity if switch over is needed. So you pay twice.

    It’s worse than you think. Ramping up and down to match wind is very hard on large conventional plant, and cuts service lifespan considerably, not to mention greatly increasing costs. Much of the time is spent in lower-efficiency mode during the transitions. Plus they must be kept “warm”, on stand-by, even when not generating power.

    Not just bollocks, a total bollox.

  63. Claude Harvey says:

    Mark Gibbas says:
    April 27, 2011 at 6:15 am

    “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.”

    Where in the world do you get stuff like this? According to the U.S. wind operators own reports of O&M costs, the O&M cost per Kwh for wind is probably the highest of any technology in the electric power industry. Those blade feathering mechanisms and transmissions are eating their lunch. The capital and fuel costs over a 15 year project life for Combined Cycle Gas Turbines at current natural gas prices is around 4 cents per average Kwh (at the fence). Capital cost alone for a wind turbine over that same 15 year life is over twice that amount and the European data indicates that the price for on-shore wind, including O&M, is 12 cents (U.S.) per average Kwh. European off-shore wind is running 20 cents per Kwh. The average at the U.S trading hubs is under 4.5 cent per Kwh using our current mix of generation. The more solar and wind we add to that mix, the higher the price will go. Unlike the U.S., where the true cost of wind is obscured by backdoor subsidies (investment tax credits; accelerated depreciation; depletion allowances; direct subsidies), to their credit the Europeans are paying the true cost for wind and solar at the fence in the form of hyper-inflated tariffs and the numbers could not be clearer. Economics is NOT a valid argument for either wind or solar, but solar is much much worse in that regard.

  64. racookpe1978 says:

    Mark Gibbas says:
    April 27, 2011 at 6:15 am

    “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.”

    Let us continue ….

    EVERY power plant of EVERY type is built only after long-term cost-benefit analysis incorporates ALL of those factors from initial design through permitting through fuel through training and paying operators through maintenance, repair, demolition, and site restoration.

    The future cost of money, future taxes, future pay raises for future operators, future maintenance, etc … are all factored in. Current fuel cots, expected future fuel costs, etc are included.

    And windmills do NOT add up to anything except a loss – UNLESS (big “unless” there!) – you add in government tax-money subsidies. Without constant government money from the rest of the taxpayers to the green lobby, no windmill makes money.

    Wind turbines- on average worldwide – only deliver 21% – 23% of their RATED output. So, to get the “nameplate” rating of ONE windmill, you need to build 5 windmills.

    Worse, winds are notoriously random – but the local winds in one area are going to be essentially identical for that region (winds in any 100 km x 100 km square are going to be the same since weather does not vary), so to get even your 5 windmills running even part of the time, you must build them spread out over several tens of thousands of square kilometers, repeating your 5 windmills every 60 km.

    So now you must build not 1 windmill, not 5 windmills and a local distribution center and transformer grid, but 10 groups of 5 windmills and 10 distribution centers.

    All of this to get the (unreliable) nameplate power of one windmill – part of the time.

    Classically, I understood the thumb rule for the second windmill was 10 blade diameters between following windmills, and 5 blade diameters between adjacent windmills. So that now needs to be “miles” of distance between rows.

    More – MUCH MORE – wasted copper and wasted energy and wasted concrete and wasted money building the high voltage wires to connect all of the windmills together. (Most nowadays are in a single line across the absolute edge of a hill or steep slope above a long valley – what Smith above described as the “natural” turbine input duct. This further limits available sites.)

    So – Even ocean based windmills now need to be separated by more space. Money. Money. Money. For nothing – 96 percent of the time.

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