Clean Power manmade wind for low cost wind power

Published on February 2nd, 2013 | by Tina Casey


Man-Made Wind For The Wind Turbines Of The Future

February 2nd, 2013 by  

Low cost wind power is extending its reach throughout the U.S., even in regions where wind conditions aren’t exactly optimal for powering a wind turbine. New transmission lines like the Grain Belt Express are helping to make that happen, and there could be a third option on the horizon if all goes well for Clean Wind Energy Tower, Inc. The company has developed an energy efficient way to generate wind in a steady, reliable stream, and the technology is promising enough to catch the eye of ARPA-E, the Energy Department’s cutting-edge research funding arm.

manmade wind for low cost wind powerLow Cost Wind Power from Man-Made Wind

Clean Wind calls its technology the “Solar Wind Downdraft Tower,” and that pretty much describes what it’s all about: a hybrid system that harnesses solar energy to create wind.

The infrastructure basically consists of a large cylindrical tower in which a fairly powerful downdraft is created when water meets hot, dry air.

To heat the air in the tower, the system relies on ambient energy from the sun. The water is introduced as a fine mist across the top of the tower. As it evaporates, the air becomes cooler and denser, and this air falls through the tower at a pretty good clip, reaching speeds in excess of 50 mph.

At the bottom of the tower, the wind is diverted into tunnels in which the wind turbines are located.

Depending on the prevailing wind conditions in any particular region, the company also anticipates outfitting the tower with vertical wind vanes that capture additional wind energy.

You’ll notice that there are a couple of catches, namely that the basic technology is best suited for regions where ambient temperature and water supply are sufficient, but that still accounts for a pretty good chunk of the U.S.

With the aforementioned wind vanes included, the system’s cost effectiveness could span a wider area.

Making Wind without Using Energy

In case you’re wondering how that water gets to the top of a tower without using energy, it doesn’t. The water is pumped, but the system generates enough wind energy to power its own operations, with plenty left over of course.

Here’s what the company is looking at in terms of the system’s capacity:

“…As currently designed, the Company anticipates that each Downdraft Tower will be capable of generating, on an hourly basis, up to 2,500 megawatt hours, gross, of which approximately 1/3 will be used to power its operations. From normal to ideal circumstances the Tower should have a potential hourly yield of 1,100 to 1,500 megawatt hours available for sale to the power grid.”

From Downdraft Towers to Silos

Obviously, Clean Wind is banking on bigness, but you can see the same basic concept at work at the other end of the scale.

One example is a system for small and medium-sized farmers to generate low cost wind power by converting their existing silos to create a steady, compressed air flow strong enough to power a small wind turbine.

We Built This!

Not for nothing, but the silo project is being partly funded by the U.S. Department of Agriculture with a grant of $100,000.

In that regard, it’s worth noting that the developer of the technology, an Air Force veteran and Arkansas native, was partly inspired by a desire to help his fellow Arkansans create a sustainable rural economy, enabling small communities to remain viable.

Meanwhile, Clean Wind Energy Tower is hoping for some big love from the Department of Energy. The company was selected as a semi-finalist for the the ARPA-E Energy Innovation Summit taking place later this month, which features a new $150 million funding opportunity for breakthrough technologies.

Note: Clean Wind has begun the process of formally changing the company name to Solar Wind Energy Tower, Inc.

Image: Low cost wind power system courtesy of Clean Energy Wind Tower, Inc.

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About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.

  • Dileepa Dharmasiri

    what if we could make more small wind turbines , spreading all over the world !

    • So far, these simply haven’t been cost-competitive compared to conventional wind turbines or solar panels. Personally, I wouldn’t bet they ever will. The good wind is up high (where big wind turbines go), and solar is likely to be the dominant source of power in the future — more potential there.

  • bkhebert

    This is like de jeu vous for me, because in 1980 I wrote a technical paper on something very similar involving solar energy. The more underground for this endeavor will prove the most successful. I also have Ideas that can enhance the wind generation process to its maximum…

  • one problem is that humid air is less dense than dry air at the same temperature.

  • VietnamRyan

    I like it and have a few ideas to improve it

  • The need for a large source of water would render this idea virtually impractical as it places additional demand on existing water sources.

  • Scott Parker-Copestick

    why would you change your name so that the anacronym is S.W.E.T.I?

  • In case someone wants an easy way to understand air being used as a force because of it’s weight…’s a weight measurement you can visualize right in your own home or office….
    The air in a room 8’x10′ that has an 8ft ceiling, and is at sea level, at a standard room temperature range, weighs approximately 62#…. so the air in an average size bedroom room weighs about 125#….and in an average 3 brm home, the air would weigh about 1000# to 1200#. Now…think about your car, and figure that the air in your home weighs about 1/3 as much as your car weighs.

  • I wanted to stress the point that these hucksters are touting this contraption as a perpetual motion machine….and the only one in existance, operates with permanent magnets on a ring, and uses the opposing force of same polarity repulsion…however, the magnetic fields created in this manner, have no real risidual energy to drive anything else but the device itself.
    Theoretically, the only way to “beat the odds” so to speak, of developing enough energy to exceed the various existing wind and solar devices, is to find a more efficient way to capture the energy from the sources they get it from, or to combine them to create a synergy.
    Remember, the shoes of Da Vinci, Einstein, Planck et al, are pretty big to fill…but then again….nothing existed until someone invented it.
    My company actually has a product which exceeds 100% efficiency. It’s a device that holds an average of about 20 common hand held size objects in a 3″x5″ space….such as sizzors, pens, rulers, a small stapler, cellphone, etc. and allows you to remove and replace all items with one hand, without anything needing to be held aside or removed to get to it….even if there is something like a paperclip with 10 other larger items surrounding it….so it IS possible to beat mother nature with something….However, not using this wind tower! Lol

  • Very innovative approach to harness power from wind.
    There is Wind Chimey.

    Air is a fluid that has weight, so when it gets moving it exerts
    pressure on anything that gets in its way. If you have experienced a fifty mile per hour wind, you know all about it. Just like water, air flows in eddies and currents when it gets turbulent, as it does flowing around obstacles. The fact that air is invisible makes diagnosing wind-induced venting failure mostly guesswork, but there is some science that provides guidance.

    The higher the velocity of air flowing over a surface, the lower the pressure it exerts.The higher the velocity of a stream of air, the lower is the pressure that it exerts on the surface it is flowing over. It is this principle that gives an airplane wing its lift. For the same reason, wind flowing over the top of a chimney can increase draft by producing a driving pressure that assists in pulling exhaust gases from the chimney.

    Despite the fact that wind flowing over a chimney can produce a driving pressure, it cannot be depended upon for appliance performance because it is variable and unpredictable. The only dependable driving pressure in a chimney operating on natural draft is produced by temperature difference.

    Wind can force exhaust back down a chimney without a cap.For example, wind can often flow down towards the top of a chimney after passing over an obstacle like a roof, adjacent building or trees. Wind may also approach the top of a chimney from below after flowing up a roofline to a chimney penetrating the peak. Wind tunnel testing has demonstrated that wind flowing from either above or below the chimney top can be adverse to upward flow by creating positive pressure at the top of the chimney.
    Dr.A.Jagadeesh Nellore(AP),India
    Wind Energy Expert


  • Bob Bench

    This system would produce an enormous quantity of mineral deposits. Anyone who has ever used an evaporative cooler knows that these deposits cling tenaciously to the nearest surface. They are very difficult to remove.

  • Sometimes, ya gotta wonder where some people got their degree in physics.
    Look, for a structure this large in diameter and this large vertically, you’d need at least 5 sq. ft. of water at over 2400 psi to climb to it’s height. That’s 1,000,000 lbs. of water needing to be constantly pumped to the top of this Goldberg.
    The world’s largest motor is 140 MW (that’s 189,000 hp) and the equivalent of just under 30 ea., 5 mw wind turbines….that’s 12,000 ft of rotor length….the picture shows manifolds to be approximately 1/10 of it’s height, so 300ft turbines….so this device would have to have 40 turbines turning at the same speed as a windmill to put out 140 mw…and these people claim to be able to produce at least 1000 mw….over 7 times the power of 30 windmills….210 windmills…..a 5 mw windmill puts out 6750 hp….so this device would be putting out 1,417,500 hp.
    So folks, when a cubic ft of water weighs 62 #, and a cubic ft of air with a negligible amount of water weighs .07 lbs. you’re just not going to get a million and a half horspower….and the air won’t fall at 50 mph, because the air underneath it will slow the column of downward traveling air, from the narrowing openings of the manifolds at right angles creating a tremendous amount of angular force, thus greatly slowing down the speed of the not very forcefull misted air….
    However, there’s yet another issue….they are describing a perpetual motion device….the USPTO says they won’t even look at a patent app for a PMD, unless accompanied by a working protype

  • You could add another tower to the equation to capture the wind “exhaust”. Heat the air in that tower with solar and create an up cycle, put a wind turbine at the top thereby generating additional power

    • David, there would be almost no kinetic energy left after the turbines absorbed the energy from the falling air. Air loses heat so rapidly, that the available energy from the exhaust air’s movement from the turbine and it’s further travel would leave it with very little energy. Also, even though air is 800 times lighter than water, that volume of air weighs millions of tons.

      • Zer0Sum

        They could put CSP/PV on the roof and sides of the tower and use that to generate the electricity needed to power the water pumps. They could also build them deeper into ground to get some more thermal efficiencies.

        The process of construction would create a large number of “green” jobs and once built they would require very little maintenance. Certainly a hell of a lot less risky than any form of nuclear power generation.

        There are so many ways to utilise the complete selection of solar/wind/thermal options in Hybrid solutions that we make ourselves look like complete idiots by continuing to rely exclusively on fossil fuels for our electricity production.

        • It takes 4400 panels to produce 1 mw….and 1350 hp will absolutely lift millions of lbs of water up to the top of this thing….even THEY are saying it would take 1/3 of 2500 mw to run this thing….that’s about 800 mw, or 3,520,000 panels to power it…even if the pump used only 10th of that, it’s still 320,000 panels…..which would require about 160 acres, or more.
          If you will read my previous post, from yesterday (2/3) you will have a lot more understanding of why this contraption could never work…..and not work with less power output…not work at all.
          I’m not picking on you, as there are lots of posters who also mean well when posting, but please remember that there are some posters with science educations in these kinds of blogs….try to ask more than tell if you want credible answers

        • Sacha B. Nice

          power gen is ALL about consistency/reliability. Nuke gives you that. Wind, solar, do not. About the only thing that is constant in these green environments is wave tech. Problem is all of the things that can tangle most wave generators. This may work fine for hot dry days… what about night, winter, inclement weather?

          • Bob_Wallace

            Wrong. Power generation is all about supply people electricity when they want it, for the best possible price, and with the least amount of risk.

            Nuclear is too expensive and brings an unnecessary amount of risk.

          • nope, baseload power sources that take forever to start up and shut down (and are quite expensive) are a thing of the past, going out of style fast. there’s a reason (or several) why solar, wind, and natural gas dominate new power installations all around the world:

  • Colin Megson

    Lovers of electricity from wind turbines – get off the band wagon while you can. The truth shall set you free – this is what it really costs:

    • Bob_Wallace


  • akb

    We also wrote about this back in March…with link to video presentationl…


    Current design plans predict that each Downdraft Tower would be capable of
    generating as much as 2,500 MW per hour [sic.] of clean, renewable
    electricity. Approximately 1/3 would be used to run the tower itself.
    After all is said and done, a potential energy yield of 1,100-1,500 MW
    per hour [sic.] would be available for sale on to the power grid.

    Clean Wind Energy Tower predicts the energy capacity factor for the
    Downdraft Tower will be 51%, with prime production periods in daytime
    and evening in the spring, summer and fall, which would dovetail nicely
    with energy usage patterns. Equipping the Downdraft Towers with External
    Wind Capture, which the company says would keep working 24/7 with an
    energy capacity factor of 75%, raises the predicted overall energy
    capacity of the system above 60%.
    Clean Technica (


  • jdavies

    This seems promising but rather extravagant. Seeing as you are more familiar with energy outputs etc, can you (or somebody?) please put one of these towers in terms of its equivalent in wind turbines and also its equivalent sized solar farm? Would one of these replace a mid size power station? Thanks.

  • Curious

    I agree. I’ve seen various concept drawings of this for many years. I wonder why I’ve not heard of any in production. As far as using water, hmm. Are the following thoughts accurate? The tower height isn’t specified here, but from freshman level meteorology we learned the adiabatic lapse rate of a column of air is three degrees F per thousand feet of altitude. The tower system will need to access the different temperature air masses, and the larger the difference between the heated column of air and the temperature at the top of the column, the greater the airflow. If the mass of descending air is sufficient to spool up the turbines, an equal mass of air had to ascend the tower by using “ambient heat” energy. If the step of introducing water to reverse the flow of the air mass from ascending to descending is taken out, the ascending air exhausts from the tower into the lower temperature air at the top of the tower. The direction of the turbines at the can be reversed from spinning from the forces of the descending air on the turbine airfoil shape, to spinning from the equal force of ascending air on the turbine airfoil shape. Less, complex? No water needed?

    • JustSaying

      Now there are several heat towers that have been built that do the raising air dance.

    • There is no way reversing anything is going to raise millions of #s of air without using more energy than is produced…this contraption violates the laws of thermodynamics, and what you are saying, does it to an even higher degree.

  • Bob_Wallace

    I’m betting that these things won’t produce electricity for a low enough cost to compete with PV solar. There’s too much infrastructure to construct.

    Watch this site for news of new, lower electricity prices coming to our grids…

  • JustSaying

    Been seeing this for what 40 years now? Problem is you need hot dry air and a large source of water, they often don’t go together. See a Isreal company wanting to use salt water, which was proposed for out west say 20 years ago. But haven’t seen any get past pictures. If you can design it to capture the salt, and not have the salt destroy the turbins. Then any where with ocean and desert would be set. A big pipe from the coast in what 100-200 miles and you got desert in California. Less for Az if you pipe through Mexico.

    • JustSaying

      Here is the Israel company youtube
      Can always be hopeful that a new look at a old idea will pay off.
      The idea is that the water cools the air at the top of the tower thru evaporation and that is why the air is cool and drops. As for size says 1000m tall 400m wide. That is a tall tower. You need deep deep pocketc to build the first with no prove it will pay off. Look at OTEC the US government built a prototype, proved it worked, said we don’t make comerical size power plants (lets ignore those old damns). But no deep pockets stepped forward to make a large scale plant and prove you could make money with it.

      • Bob_Wallace

        Deep pocket money people usually hire some knowledgeable engineers who work through the data available to see if investing a lot of money is likely to produce earnings.

        • Yes Bob, the the deep pockets in power are very conservative, so the provable payback needs to be 2-3 times what they can get with current carbon fuel or the change isn’t worth the risk. Else you wouldn’t see companies like Mosaic and would see a lot more PV, wind, and geothermal already.

          As JDavis question on size. A net “NamePlate” power output of 1500 MW, typical land wind turbines are are now at the 2.5-3.0 MW level, Offshore ~5MW. So this would be like 500-600 on shore wind turbines. It is sized about like a big nuclear unit. Most of the new units are between 1000 and 1700 Mw electric. Often a plant will have multiple units.

          • Bob_Wallace

            I see the Google guys putting hundreds of millions into potential clean energy solutions. Bill Gates has invested many millions into novel ideas. Elon Musk has certainly funded some groundbreaking technology. Vinod Khosla has invested all over the place on seemingly long shot. And they’re just the big name people we hear about.

            I think it’s worthwhile considering that people with billions to invest and an interest in clean energy don’t seem to be showing interest in this idea.

            That’s not saying that the idea is bad, it’s just flag that is waving and might be worth observing.

            Consider. This idea might work. It might make a lot of electricity.

            But what if the electricity produced would have to be sold for 10 cents per kWh in order to keep from going bankrupt?

            We’ve got other way, proven ways, to produce electricity for less than 10 cents.

            Mosiac is something different. It’s a crowd-sourcing of loan money. They are financing known technology.

          • I agree Bob, I don’t think this is going to fly. Just the engineering unknown of building tube structure 1500m tall and 400m wide (over 4 football fields) is a massive undertaking. This was first designed in the 70s, and I think it will still be on the drawing board in another 40 years. Ones self assembling structures come along it will be a good way to use saltwater to add moist air to a desert, just need to design the bottom to catch the salt and not send it out on the land. That was part of the plan when it was in Poplar Science when it first came up.

  • darklight_413

    This should be a top priority development. This will alleviate the problem with bird strikes.

    • globi1

      One could shroud wind turbines and add a net on the ‘intake’ side. The shrouding would make wind turbines even more efficient. It would still make wind energy more expensive though, but probably not as expensive as energy from this 40 year old behemoth.

      • Bob_Wallace

        A small 2 MW wind turbine has about a 100 meter/300 foot “wing span”. An American football field.

        Imagine the size and weight of a shroud that would direct wind into the blades. A 300′ wide doughnut, designed to “catch” the wind.

        Imagine how strong the tower would have to be to support all that mass in a strong storm. Turbine blades can be turned so that their thin edge faces the wind when winds are too strong. The shroud would be a massive “sail” putting immense force in play to bring the tower down.

        Stick your hand out the window of a fast moving car. Turn your palm toward the wind. Then the edge of your hand. Back and forth a couple of times.

        Your palm is the shroud.

        A net in front. It’s time to move past the bird kill stuff. Wind turbines kill so few birds that it is simply not important. Extensive field studies find that most turbines kill 0 to 2 birds a year.

        Domestic cats in the United States kill up to 3.7 billion birds each year.

        Cats that have outdoors access kill between 30 and 47 birds apiece in temperate parts of Europe and North America each year.

        30 to 47 bird deaths per cat.

        Trillions of birds are going to have their habitat destroyed if we don’t prevent the worst of climate change.

    • Ronald Brakels

      Bird strikes aren’t a problem. Not in my state here in Australia and we get about a third of our electricity from wind. Maybe our birds are just smarter than in other countries, but what is actually happening is that the first wind turbines, such as the first ones at Altamont Pass in California, were tiny by modern standards and so their blades moved very quickly. So quickly that even birds couldn’t see them and so a lot of raptors got hit. Now that we use large modern wind turbines which have blades that are much easier to see, bird hits are quite rare. The Royal Society for Protection of Birds in Britain is building a modern wind turbine at its headquarters to underscore how clean energy from wind power protects birds by mitigating global warming.

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