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.

Any kind of water - from a sea or drainage ditch - would be added to the top of the tower. The water would cool the hot air at the top, and the heavy cooled air would sink downwards, gathering speed as it falls, and would be used to power turbines at the tower's base. The turbines would be connected to a generator, which produces electricity.

Because it relies on the sun for hot air, the Energy Tower is considered a type of solar power. Due to the original hot air required at the top, the concept would work best in hot, dry climates. The team has identified regions in about 40 countries where towers could work, including in the Middle East, Australia, North Africa, California, and Mexico.

The researchers also predict that the project would be cheap - electricity generated from this method would cost just 2.5 cents per kilowatt-hour, which is less than a third of the cost of electricity in Israel today. It's also cheaper than solar, hydro-electric, and wind power.

Zaslavsky explains that the tower design could also be used for water desalination, producing fresh water at only half the cost of existing desalination technologies. The water reserves might be used locally for a number of purposes, including desert irrigation, the production of bio-fuels such as sugar, or for fish farming - an energy-efficient form of agriculture.

Finally, the Energy Tower might help the Earth cool itself, and actually reverse global warming. "Hadley Cell Circulation" is a natural process whereby the earth cools itself, but it mostly occurs only near the equator. But by cooling air around it, often in desert regions, the Energy Tower could expand the effects of this global cooling process.

While the researchers are confident in their technology, they're still waiting for investors to finance the project before taking the next steps, including building a prototype. But in the end, they hope that the Energy Tower could be the key to providing cheap energy for large populations.

Via: Israel21c

Lisa Zyga
Science Blogger

Dec 9, 2007
by beckster (not verified)


150 man-hours since 1983? Doesn't sound like much of a research project. I think I've spent 150 man hours eating lunch at work this year.

Dec 9, 2007
by bill (not verified)

This Tech

This tech has been used in PHX for cooling outdoor areas in the hot summer months. This is proven low cost tech .. selling condos around the outside of the structure could reduce the cost further. Build it in Arizona with 360 days of sun.

Dec 9, 2007
by Energy tower (not verified)

Looks promising

"150 man-hours" or "150 man-years"? ;-)

This looks promising, but will it deliver? I suppose it's up to the possible investors to decide!

Dec 9, 2007
by Lisa Zyga


oops, yes, it's supposed to be man-years...thanks for the correction!

Dec 10, 2007
by Anonymous (not verified)

did sound like very long to

did sound like very long to me either, for something so promising you would think they could spend more time developing it unless it is as far as they can take it at the stage before big money? Anyway I'm intruiged and hope they build one heaven knows we need someone to at least Try Something rather than just talk about the possibility of possibly discussing maybe doing something at some theorectical future date

Dec 10, 2007
by Anonymous (not verified)

Monster Tower

At 3000 feet high and 1200 feet wide, this would likely be the worlds largest construction project if buildlng it is feasible. I can't believe that the energy required to pump cooling water up to 3000 altitude would not exceed that gained by extracting the energy from the falling air mass.

Dec 10, 2007
by Anonymous (not verified)


Sounds like a good idea. Too bad about the "man-year" mix-up. Glad you cleared that up.

They have probably thought of this, but stationing all this responsibility in one building (ie. the responsibilty of providing a large portion of the world with energy) is probably not so great an idea. For example, imagine some diabolical Hitler-type dictator. He wants power. He blows up the big energy tower. The world is screwed for a bit.

It's just too easy of a target. But a very brilliant idea anyway. Let's keep looking into it.

Dec 10, 2007
by Anonymous (not verified)

so what kind of costs are we talking about

This looks ok, but I saw something very similar from an australian company last year. I dont remember the name of the company but im sure if you google it youll find it.

My main question is what kind of initial construction costs do they estimate, I mean 3000 feet tall and 1200 foot diameter that sounds very expensive, though if it delivers itll be well worth it.

Still I dont know about the intellectual property status of this object, like I said im a 100% sure I saw somthing very very similar out of australia

Dec 10, 2007
by Woodrow (not verified)

I'm hoping this is a typo, because...

Only 150 man hours in over 24 years of work? That's just about half an hour a month dedicated to this project. Doesn't seem that dedicated to me :P

Dec 10, 2007
by pete (not verified)

How much water would be lost

How much water would be lost at the top due to evaporation in the hot dry climate suggested? Would this not impact adversely on the surrounding countryside as water is sought to precipitate the cooling effect?

Dec 10, 2007
by Anonymous (not verified)

and how much energy would be

and how much energy would be used pumping massive quantities of water over the 3000ft. height of the tower?

Dec 10, 2007
by Rohan (not verified)

erm, one question...

How does the water get to the top? Surely pumping water 3,000 feet up is gonna take a lot of power? Especially if there's enough to power turbines?! I hate to piddle on the bonfire, but I don't like to get carried away when I hear of the latest uber power generation facility?!

Dec 10, 2007
by Anonymous (not verified)


wouldn't the reverse global-warming bit effect the immediate climate around the structure causing damage to the desert-like eco-systems proposed?

Dec 10, 2007
by Anonymous (not verified)

Need some more details

"Researchers have designed a product that its inventors claim could easily produce between 15 and 20 times the total electricity the world uses today"

The above quote needs to be explained. Are they trying to say that one of these can produce that much energy? It sounds like the writer should explain on this, because it sounds like he got the wording wrong.

I can't picture this producing much more energy then a standard hydro-electric dam.

Now if only someone could harness the power of lightning.

Dec 10, 2007
by Kilgore Trout (not verified)

Dream Weaver

Another one of those stinkin dream fests that need financing. How about a 100ft. size working model first? If it works I'll donate a coupla
bucks. Seeya

Dec 11, 2007
by Anonymous (not verified)

15-20 earths makes no sense

what if the maximum number of potential locations of operation had this or just from one of these?

A company in australia called enviro-mission already invented this years ago

Dec 11, 2007
by Anonymous (not verified)

Learn to Read

IT is 150 man years
as in 1,314,900 man hours
Also it is the opposite of a solar updraft tower
water would not evaporate as it is not what turns the turbines it would be kept in a sealed system
Cooled air coming from above is what turns the turbines

Dec 12, 2007
by Anonymous (not verified)

Working Model

ok ... Fine.
Put a large circular space truss on the top of a very tall building ... line the space truss with a light weight fabric to enclose the structure .... Pump some water to the structure to mist nozzels. Put a large pipe down the side of the building ... AND TEST THE DAMN THING. Let's find out if you develop the momentum you think you will. That experiment can be easily funded and will be proof of your concept.

Dec 12, 2007
by Sir Theas (not verified)


this could also help in reclaiming the deserts making them habitable , For the population boom that is coming

Dec 12, 2007
by Anonymous (not verified)

Does this seem impossible to anyone else?

Not to burst anyone's bubble here, but wouldn't the energy required to pump enough water up 3,000 feet be far more than the energy gained from the falling air?

Dec 13, 2007
by Erik (not verified)

Hey, sounds great! I also

Hey, sounds great!

I also hear that by the year 2000, there will be no more traffic jams, because we will all be flying hydrogen-powered gyrocars!

Dec 14, 2007
by Anonymous (not verified)

getting the water to the top

Would it work as a scaled down prototype? It might need the 3000 ft of fall to generate enough energy...

I'm sure that over the course of the last 150 years, someone asked the question about how to get the water to the top. If it can really produce those amounts of electricity, bleeding some off to pump water up wouldn't really matter. It is a long way to move water up, but who's to say that a solar powered Archimedes screw wouldn't do the trick? In that kind of climate you might also be able to use solar to pre-heat water so that it only takes a small amount more to turn it into steam, at which point it rises by itself and you just need to condense it at the top.

I say build it and see what happens, but it sure would be nice if it didn't have to be 3000 ft tall...that's more than 1.5 times as tall as the CN Tower.

Dec 15, 2007
by brainiac513 (not verified)

Power & sewage

The equation for lifting a liter of water 3,000 meters is pretty straightforward.

My question is that if we are lifting sea-water, swamp-water and doubtless sewage to these heights, what is expected? Clean water, power and -- what's missing?

Will the heat evaporate out, to be drawn down the tower, leaving salt crystals and detrius? Where? Stuck on the fluted rim of the tower? To trickle down return piping, only to be chisled out every so often, when it tends to choke and clog? Sit there on top of the tower, growing with time? Where is the waste-return? It sounds like we're lifting water up the tower, only to throw it down the tower. If that gives us clear water, easily separated sludge (either fertilizer or table-salt, as you choose,) and more power than it took to bear the salty-sludge-water up, in the first place, why, then more power to us! Definitely worth its salt.

I'm having trouble seeing all this, however. Is it possible the water is lifting itself, from evaporation at ground-level, via heated (greenhouse effect?) pipes embedded in the cylinder walls?

This report is simply unclear - it leaves too much to the imagination. And MY imagination is an awesome and terrifying thing to behold.

Or - as my good friend Pinky recently observed: "If we manipulate climactic variables with neutrinos, to produce agricultural economic equilibrium ... you might just be a redneck! Yey! Narf!"

Hey, Brain! Waddyah wanna' do tonight?
The same thing we do EVERY night, Pinky ...

Dec 16, 2007
by R. Lent (not verified)

Different power towers

We've got two different types of power towers here, both of which work on solar heating. This article is about an idea that is new to me; that of cooling the mass of air at the top of the tower by evaporating waste water. Of course this water has to be raised to the top of the tower.

The other is the one proposed for use in Australia, the heating of air at ground level by glasshouses and letting it raise up inside the tower. This one had a pilot test model made in Spain which produced current on line for a couple of years. It has the interesting effect in that it produces a fair amount of fresh, clean water at the top of the tower. My gut feeling is that the raising hot air tower would be more efficient.

I would like to offer my own observation here. The cost of building these towers would run into billions. A straight, neat looking tower would be more efficient but if one looks at steep dry mountain slopes such as those of the N. African Atlas Mountains, one could build an inclined tube up a South facing slope for far less money. The mountain's already there!

Dec 19, 2007
by Rob Heusdens (not verified)

can it be build?

This energy tower works on a different principle then the Australian environ mission tower.

If it could be built, it would be nice, since there are potentially a lot of places where it can be built. But building some scale models first would seem like a good idea, and then scale it up later, since the building delays in the enviro mission tower was caused just by that, scaling it up too big in one step (the Spanish demo tower was just 200m high, the Australian tower was envisioned to be 1km high, but is scaled down).

As far as building a 3000ft tower, I would suggest it would not need a concrete construction, since the tower does not have to support anything. A very wide cylindrical tube made from lightweight material, perhaps even made from Helim filled sections so that the tower essentially floats, and is stretching straight up by connected cables, might do the job.

The disadvantages of this power plant are however that part of the salted water will fall outside the tower and cause the soil to become salted.

Dec 19, 2007
by Anonymous (not verified)

The really exciting aspect

The really exciting aspect of this project is its geometry: If you double the tower diameter from 1200 to 2400 feet, you could get 40 times the total electricity produced globally. Double again to get 80 times. … finally at 2^n doubling there would be more electricity produced than the total output of the sun. Could even sell it back to G_d, or open shop on other planets. NOT bad for 150 man years, hey!

Dec 26, 2007
by George Hunnicutt (not verified)

energy tower

Since it's Christmas, I'm going to "suspend disbelief" and assume this is a serious possibility. Strikes me that the Grand Canyon is as much as 5,000 feet deep. So if such a tower were built on the floor and against one side of that (or some other more suitable) canyon, and water were piped to the top edge of the canyon from wherever it may be available in sufficient quantity, then the following advantages might be gained:
(1) a taller and more presumably more efficient tower,\
(2) some energy savings in raising the water
(3) some savings in the cost of the tower, both in materials (since it could be braced to the sides of the canyon) and labor (since material could be lowered down from the top rather than raised from the ground level)
(3) more water would wind up in the Colorado River, which I seem to remember reading is so heavily used by the US that it disappears before it gets to Mexico

I wonder if that would knock a big enough chunk off of building it to get somebody to try it?

Dec 28, 2007
by Anonymous (not verified)


The idea is not to use the water to drive the turbines, but to use just enough water to cool down the air at the top. The article didn't say how much water, but seing that it is a project that has been running for nearly 20 years. I doubt that they would not think of this.

Dec 28, 2007
by Anonymous (not verified)

Some of the dumbest posts

I've seen some of the dumbest posts, but this thread takes the cake!
It's not 150 man hours it's 150 man years (big difference and stop wasting your companies time like that)

The solar updraft tower doesn't even come close to this in terms of MW (Mega watt = million watt of electrical power) being produced.

The idea is to run the turbines off the downcoming air, not the water being pumped up. To cause the air to drop you need to cool it down. So, the you need just the right amount of water to cool down the air at the top (which is not a lot). It's not rocket science people!

The water being used is sea water, it doesn't dissapear into an alternate reality after being used and it doesn't leave the planet with aliens. It returns, like all water, back to the oceans.

I'm surprised that some of you completed the math problems correctly!

Dec 28, 2007
by Anonymous (not verified)

tower of power

let's just build a weather controlling machine while we're at it!