Energy Tower: Power for 15 Earths?

Energy Tower: Power for 15 Earths?


Researchers have designed a product that its inventors claim could easily produce between 15 and 20 times the total electricity the world uses today. Not only that, it could also be used as a desalination device and may be able to reverse the effects of global warming.

Those are pretty big claims, but the researchers from the Technion – Israel Institute of Science seem confident that the “Energy Tower” could be a major solution to the world’s problems. They’ve been working on the concept since 1983, and together have spent more than 150 man-years researching, designing, testing, and analyzing.

As project founder Professor Dan Zaslavsky explains, the Energy Tower works on the basic principle of convection: hot air rises and cold air falls. The 3,000-foot tall tower, with a diameter of 1200 feet, would take advantage of the heavy falling weight of cold air.

12 thoughts on “Energy Tower: Power for 15 Earths?

  1. Robert

    Good Morning J.W.!

    This thing would be monstrous by its description. Where could they put one up where they would not have to redirect air traffic it? What would be the force of the air current as it enters the top and heads towards the bottom?

    Anyways , as usual you have posted yet another interesting note on the topic of technology. Thanks much!


  2. James

    Hm…it’s a sound concept (we have plenty of cold air hanging around in the upper atmosphere), but I’d like them to be ABSOLUTELY POSITIVE that it won’t have any serious effects on the climate first.

  3. Mangetout

    This works by cooling the air with water, then harnessing its downward motion? How can the energy from the falling column of air reasonably exceed that required to lift the cold water to the top rim to spray it? – I don’t think this is a thermodynamic impossibility, just a practical one.

  4. Gary

    “Hot air rises and cold air falls” Yet the diagram shows hot air falling…

    I notice that the internal base seems to have fans/turbines. These would be required, at least initially, to suck in the hot air from above and pump it down through the water droplets.

    The air is dry at the top and therefore needs wetting. The wetting has to start near the top. Therefore energy is required to raise and spray the water and drive the fans/turbines.

    The only bit of Physics that I can think of that would possibly make this work is a sort of reverse Hadley Cell Circulation causing a syphon effect. If this is so, then once primed, the system may go on for quite a long time by itself – or at least until night-time.

    The tower is supposed to work best in hot dry places but also requires a large water supply.

    The actual projected size of this thing is 3000 foot high and 1200 foot across – hardly the sort of thing that 50% of the countries of the world could afford or have the skills to build.

    As a further advantage, it is reported elsewhere that the turbines at the base could be used to produce surplus electricity. This presents the prospect of a perpetual motion (over-unity) machine. As this seems to break the 2nd law of thermodynamics, and I could not possibly contradict the good Professor Dan Zaslavsky, I have obviously missed something here and will reserve judgement on the performance of the tower until a working model is built.

  5. Chris Gahan

    I think I can answer a couple of these questions.

    #1) The problem of getting the water to defy gravity has already been solved by plants — trees have a clever method that doesn’t involve a water pump at their base. It’s called “transpirational pull”. Here’s a chunk from a wikipedia article:

    Transpirational pull results ultimately from the evaporation of water from the surfaces of cells in the interior of the leaves. This evaporation causes the surface of the water to pull back into the pores of the cell wall. Inside the pores, the water forms a concave meniscus. The high surface tension of water pulls the concavity outwards, generating enough force to lift water as high as a hundred meters from ground level to a tree’s highest branches. Transpirational pull only works because the vessels transporting the water are very small in diameter, otherwise cavitation would break the water column.

    #2) I don’t think this machine breaks unity, I think it’s releasing the energy stored in “hot air”. Hot air is air that’s had lots of energy dumped into it by the sun, so much that it floats on top of colder air. The fact that it’s floating high up gives it potential energy (due to the gravity well that we all live in), and if you can cool it down, you now have a big heavy falling thing that you can use to do work. (Air is heaver than people think — there’s 2000 pounds of air pressure pushing down on every single square foot of the planet.)

    So, this all hinges upon whether the energy cost of pumping the water way up high is less than the energy they get out of it. If trees are any indication, we can probably do it. I think this idea looks fairly scientifically sound, and I’d imagine that they’ve worked out all the numbers. 🙂

  6. Dave

    If you follow the links to the source of the information ( you will find a lot more information about the idea.

    There is no mention of how the water would reach the top of the tower in the original article, however, the water would be sent down the centre of the tower and through the turbines so the net energy would be a theoretical zero. You raise the water to 3000 feet and then bring it all the way back down again. Zero change… in theory.

    The power gain comes from bringing a lot of air down with the water. Presumably the power gain offsets the real losses through friction that don’t happen “in theory”.

    I seriously doubt that the amounts of energy they are claiming they can produce are anything like what they actually will produce but the theory seems sound enough that it WILL produce energy. If you build enough of them, I guess it could produce a lot of power but the power may need to be transported a very long way to be useful.

    Unlike solar and wind power, which are dependent on the amount of sun and wind available, this technology will be dependent on the relative humidity of the air 1Km above the ground. It will probably also get a nice little boost whenever it rains.

    Of course, I will be reserving my final judgment until I see one in action.

  7. Keith

    I read about this type of tower years ago. And yes, you would need to figure out how much energy it takes to pump/suck the water to the top. I’m not sure transpiration could be used to suck the water up 3000 feet. Trees can only do it to a maximum height (according to a previous post) of 100m. This is about 2670 feet short. However when it does get to the top, it’s atomized into the air and cools the air via evaporative cooling. This air falls down the hollow tower and out the bottom past the turbines. I’m not an engineer and couldn’t competently run the energy input/output calculations so I won’t.

    However, I will say that deep mines need tons of water pumped up very deep shafts so the pump technology probably exists and if they can afford it for mines, it can’t be that expensive for a tower like this. You are atomizing the water and aren’t just pouring it out in buckets so volume probably wouldn’t be that high either.

    This would make the most sense for a place like Kuwait when the oil starts to run out. They don’t have the area for massive wind or solar farms but they do have cash now for something like this. And if you really did get a cool moist micro-climate around one of these things, it would make these places much more habitable. And you need a hot dry climate for the thing to work best which I think Kuwait does inland away from the Persian Gulf. This also means that all the seawater you’d want isn’t that far away.

    Another possible location may be Death Valley. It’s below sea level. You could pipe water from the ocean there and have it running down hill all the way. It’s also very hot and dry. But think of the environmental impact statement you’d have to do. LOL. It’d never get done.

    When I first read about this 20 years ago the proposed location was the desert southwest of the U.S. Of course, the magazine was an U.S. publication.

    I think the big obstacle is getting someone to put enough money into this to finish the research and build a pilot plant. Why build a 3000 foot tall ferro-concrete tower when you could build many conventional wind or solar farms for the same price?

    I think it’s a really cool project, but I don’t see it happening soon. The UAE and Bahrain seem to be on a building spree but they have more humid climates from what I understand. And this thing looses efficiency the more humid your climate becomes. That’s why swamp coolers will work in Arizona but not New Orleans.

  8. Pablo

    Gahan, I’m afraid the transpirational pull which you cite as a method to transport the water upwards only allows for a certain height to be achieved. I forget the exact figure but I believe it’s only a few hundred feet.

    I am intrigued by the overall idea here, cheers for the interesting stumble Dave.

  9. kasilas

    The design looks very like a solar updraft tower (see wikipedia). If such a structure was to be attempted it would be the better to use this simpler design.

    That said it is an interesting idea.

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