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Energy from High-Altitude Kites
maddmike writes "High altitude kites could produce energy equal to some power stations at a comparable cost without polluting. The technique uses a thing dubbed a 'Laddermill' - a chain of kites attached together to create a loop in the sky more than 5 miles long."
the only thing that is high.
One strong gust of wind and the earth could start spinning the other way.
Most windmills arnt 30,000ft tall, and at that altitude the winds are 20 times more powerful than at sea level. (from the article..)
Paul
"How does this differ from regular windmills?"
More surface area. The overall thing I'm worried about is the upcoming pollution of the airspace. Kind of what happened to outerspace.
What would Benjamin Franklin have to say about this?
The article doesn't say much about how such a structure could be maintained. How in the world could kites stay up for a long enough period to be feasible as a power source? Or is all this still in the "just five more years" phase?
I'd like learn more, but the article is not very helpful.
What if the entire Universe were a chrooted environment with everything symlinked from the host?
The Laddermill would only be flown where aircraft are banned. One such area is the zone along the US-Mexican border, where high-flying balloons fitted with radar are used to combat drug traffickers.
It's not even slashdotted. Yet.
-Rob
Marriage doesn't have to suck!
Also what will happen if the cable snaps. They worry about the kite, what about the heavy cables falling and destroying things down here.
With these cables how are they going to fly the kite from the ground ? Will they use turbines from the military planes to blow air ?
Anyone has more information about it ?
-a
"The Laddermill would only be flown where aircraft are banned. One such area is the" white house.
Paul
"Winds at 30,000ft are 20 times more powerful than at sea level."
It differs from regular windmills in that you should have read the article.
Don't worry, if it's successful it's not pollution we'll have to worry about - it'll be the fact that they absorb all the energy of the wind, mess up the climate, and then cause all sorts of weather anomalies. Instead of global warming, we'll have...global "stasis?"
Flying kites at high altitude isn't as easy as it seem: pretty soon you get a lot of problem from the line(s), chiefly the weight of the line, but also line drag.
The former problem is essentially a strength vs. weight problem that even high tensile lines made of dyneema won't solve easily (above 400/500m, a 6m parafoil can very well sit there and refuse to climb with standard lines).
The latter problem introduces a problem of angle, since the line becomes curved under the wind drag, which makes the section right under the kite more and more vertical as it climbs, which in turn "flattens" its incidence angle and reduces its lift. It's always possible to modify the incidence on the ground to compensate, but takeoff can get dicey then. And of course, the wind drag on the line also tends to pull the kite down, and it's not negligible with a lot of line up.
So yes, it should be possible to use kites to generate power, but there will have to be a great deal of electronic magic to regulate everything, down on the ground and up in the air, if high altitude flying is to be more than stunts performed by enthusiasts on good days with (semi-)controlled conditions.
why not use the kites to collect solar energy? Although, I don't know how better/worse this would be, but it could free up a lot of land needed to maintain solar panels - and depending on how high the kites are, could they could collect energy in nasty weather! With regards to aircraft, I'd say make these power-gathering areas no-fly zones -- otherwise how different is it from a field of broadcast towers?
Now then, Dmitri, you know how we've always talked about the possibility of something going wrong with the Bomb...
What they were saying was equal was the cost, not the total output per kite.
Mathematics is made of 50 percent formulas, 50 percent proofs, and 50 percent imagination.
If you had RTFA, they said it would only be flown during fair weather and the kites would be adapted to that days wind conditions.
actually, Ben Franklin didn't do his kite experiment at all.
I thought Franklin flew the kite because he needed 1.21 gigawatts in order to send the DeLorean back to the future to pick up a load of cocaine or something like that.
This means the cable is actually ten-plus miles long. I don't remember my differential equations from twenty years ago, but I do know that as the cable gets longer (goes higher), the amount of weight supported increases. So half the loop is a five mile strand going up, and the other half is five miles of cable coming down. It sure seems like the weight on the top kites would be extraordinary. Do we have carbon-fiber cable yet?
And what happens when lighting hits it? Didn't Tesla manage some stunning current with a structure less tall than this?
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The nice thing about some of the other alternative power systems is that they tend to be smaller scale and are backed up by the power grid or some other form of generation. If you have a 100MW kite system, it would be such a substantial source of power that providing a backup to it when there is no wind or the cable breaks, will not be trivial.
Jerry
http://www.syslog.org/
The article is very short on details. For instance, how will they obtain the the power if the kites are floating hundreds or thousands of feet in the air? Unless their tethered, in which case on whose land would they be tethered? And what would they do when the wind drops?
In the beginning the universe was created. This made a lot of people very angry and is widely considered as a bad move.
Exactly, they say,
"Professor Ockels says a few hundred of the installations, each requiring some 400 kites with 27ft wingspans, could generate enough electricity to supply the needs of a city the size of Seattle. The cost would be similar to that of generating power with polluting fossil fuels."
At a few hundred per city... that is a lot of kites..
Then you have to find the places to put them...
"The Laddermill would only be flown where aircraft are banned. One such area is the zone along the US-Mexican border, where high-flying balloons fitted with radar are used to combat drug traffickers."
http://www.hawknest.com/
Kite trains, or stacks, readily soar to heights greater than what can be attained with a single kite.
The record, set back in 1969, is 10,830 m abg. So the 30,000 ft mark has already been surpassed.
The single kite record stands at around 13K feet.
...took the US a little too serously when we told them to go fly a kite.
(ducking)
"Oh drat these computers, they're so naughty and so complex, I could pinch them." --Marvin the Martian
Have a look at some of the plans and protoype pics of this behemoth, and it becomes clear (if not in the article) that the intention is for the ladder to be ground-originated, not just ground-anchored. This means the kites are travelling up from the ground to 5 miles and back again. The volume occupied by such a structure - especially one as non-static as this - would be monumental, not to mention the massive safety margin required to have more than one in operation within a few miles of any other ladder.
So if we're looking at 400 ladders to generate enough to power a city, we're look at a good 3000+ square miles of land if we're to be sure that no ladder is to collide with another. Not practical on any scale, I suspect.
Now if we're to be sure the things don't come down every time there's a spot of bad weather, we are looking at getting them up above the common cloud-cover atmospheric strata. In that case, why the hell not just use bigger kites, no ridiculous ladder-arrangement, and use the kite-wing surface-area to convert solar-energy? If the kites are well-engineered and -controlled enough to be able to operate in such a stringently unified fashion, I'm sure the same technology could be used to keep solar-kites in the air. True, the strain on the cables would be even greater if they have to be reliable electrical conduits as well, but that's really only one of several major flaws in this project.
Frankly, we'd be better off burning drug-addled research-scientists as fuel. They're renewable, at least.
Meta will eat itself
For more details, check the official website, cleverly titled:
http://www.laddermill.com/
or, for that matter, do a Google search for "laddermill":
http://www.google.com/search?q=laddermill
Now how hard was that?
I say we just take the people who came up with this and chain them to an exercise bike for power, anyone with me?
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This is a really interesting concept. The designers say they won't fly the kite except in good weather so they won't have to worry about electrical storms etc. but I wonder if they have considered the atmosphere's natural electric field as well... It is estimated that the natural electric field potential between the earth's surface and the ionosphere is in the hundreds of thousands of volts range. While the current is usually very low for small but rather tall structures (regular kites, radio towers etc.) I would imagine that having a huge 5 mile wide kite 30 thousand!! feet up would make an immense difference in the current transmitted through a conducting wire to the ground. We may be talking about tens or perhaps even hundreds (??) of watts here. This will have to be dealt with and I imagine it could actually be used to perhaps, power some backup or secondary control equipment way up there.
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Well, speaking of that experiment, I wonder if a blast of lightning would cause either even more power to be created or just screw up everything?
Most of the places where aircraft are banned are due to other dangerous activities, such as live weapons testing. Not a good place to put infrastructure.
As far as the balloons on the border, here is an example from the descriptions on the appropriate aeronautical charts (referring to the few balloons on the border) -
CAUTION UNMARKED BALLOON AND CABLE TO 15000 FEET IN R-6317
The entries for the few other sites list alitudes of 14000 or 15000 feet. The chart doesn't say that aircraft are banned, but most pilots would avoid flying around the balloons just to be safe. In any case, it probably isn't a good idea to put kites on a cable in the same place as balloons on a cable, due to the risk of becoming entangled.
My personal guess is that the FAA will shoot this project down well before it gets off of the ground, unless the kites are equipped with transponders (since they will be in CLASS A* airspace) and lights (so that pilots flying VFR can see and avoid).
* For those without an aviation background, all aircraft in CLASS A airspace are required to fly instrument rules, have transponders, and are controlled by controllers on the ground. In the US, Class A airspace is all airspace between FL180 (about 18,000 feet) and FL600 (about 60,000 feet).
I wonder about what happens if the line breaks.
Reminds me of something I saw when I was a kid. My dad and I were fishing off the coast of Cape Cod. The boat we were in was a 23' center console with twin 135hp engines. If memory serves me (this was some 25+ years ago) the boat would do about 40mph on a flat calm. Anyway... There was a good stiff breeze, good for sailing, kight flying, etc. At one point not too far in the distance we saw an orange kite flying in the sky. It was one of those $1.99 plastic things you can buy in any toy store. Well it didn't take us too long to realize that nobody was flying the kite because they'd have to be in the water given its location, and there weren't any other boats in the area. We decided to investigate (the fish weren't biting) so we headed towards the kite at full-throttle. It took us about 45 minutes but we eventually caught up with the kite. The string had apparently snapped or whoever was flying it had let go of the string. Enough string was dragging in the water to create just enough drag to keep the kite aloft, and the kite was dragging it through the water at a pretty decent speed. If the boat wasn't as fast as it was we probably wouldn't have caught the kite. We figured it could have made it all the way to Europe in a week or so if we let it. (Makes for a good story anyway) But it ended up in our closet instead.
I suppose as long as the kites in this ladder-thingy are designed properly they would continue to fly upright. But unless they have enough drag (like the string in my little tale) I'd suspect that the wind would just blow it out of the sky if the line were to break.
Mary Poppins would approve. And we all want to please Mary Poppins.
Heck, I figure you could get about 1.21 gigawatts easily.
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The idea of tethered high altitude wind power generation has been around for a long time. The people behind Sky Wind Power Corporation (http://skywindpower.com) have been developing their technology since 1979.
They do not use kites but a tethered electrical generator, like a helicopter with 2 fifteen foot rotors and no cabin. The documentation on their site seems to cover a lot of questions that would come up here, especially about the tether etc.
It is just sad to see another australian inventor having to go overseas to try and get their idea noticed.
If I had to rate the validity of ideas just by hearing an intro to the idea itself, this would score lower than cold fusion, harvesting cow farts, or launching satellites with a giant ACME slingshot.
Table-ized A.I.
You miss something, young teenager shaking in righteous angst...
The industrial world has a vested interest in maintaining itself and not destroying itself or us: If there is no civilization or people to buy goods and services, then money and soon power (as in power of the people, not nuclear power) go bye-bye.
It's simplistic and misses all those pesky nuances, but true.
Now, whether or not the industrial world _knows_ how to maintain itself and not destroy us... THAT's another question...
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The numbers don't make much sense. 100 megawatts is about 75 MILLION horsepower, or about 35 BILLION pound/feet per second. It would take a HECK of a kite string, probably thicker than a suspension bridge cable, to bring down that much power. Just supporting the cable is going to take a heck of a high wind.
I don't see many people analysing deeply the environmental impact of those technologies. Suppose EVERYBODY started using wind and sea power... couldn't this change el niño's mood or something?? Possibly the impact is very weak, but I would like to see the figures. And what about uniting the useful and the disagreeable? what about solar power centrals in the poles, where we are having already too much solar radiation??? :)
Nicolau Werneck - NIC1138
"The secret of genius is to carry the spirit of childhood into maturity" -- Thomas Huxley
Drawing of the system
Look at the math.
A person can generate about 1/4 horsepower with an excersize bike. Given the daily rate for unskilled labor in many countries now, we could simply rig up a giant wheel like what Conan the Barbarian pushed around as a slave in that clearly prophetic movie.
Given the cost of building a nuke plant, then running it, getting rid of the waste, (hiding it really well for a really long time), and cleaning up after it -- it would be cheaper per kilowatt to simply have a bunch of low paid people push giant logs around in a circle.
The economics are outstanding. Its great excersize, and the power companies would be incented to provide health care at the same time. It provides plenty of jobs for unskilled labor, and could quickly be set up in the lowest income countries.
All in all, its a win-win. Best of all, it doesn't suffer from the one drawback everyone is clearly afraid to speak about with wind-power, which is the potential for slowing down the rotation of the earth! Clearly a danger if ever there was one. Why, if we slowed down the earth, and there was no centrifugal force apposing the gravity of our planet we would all be crushed! Oh the horror.
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The power is generated by the action of wind on the kite producing lift on half of the loop, and through manipulation of control surfaces, subsequent down-force on the other side of the loop. It's the mechanical conversion of wind-power that is harnessed here, so the simple lift generated by a blimp wouldn't work - how does it go down after it's ascent?
However, I think you'd be correct in another regard - having the kites anchored to a floating point (for example a blimp) would allow for a much more efficient system since the kites wouldn't have to go through thousands of feet of significantly slower wind each cycle. There's hope yet...
Meta will eat itself
This laddermill requires a lot of untested technology, and some of the problems don't seem to have been addressed at all (such as how the kites 'know' if they should be going up or down, how to make cables that never break but are light enough to lift, and how to stop the 'up' kites and 'down' kites colliding.
Given that all the down kites, and the up kites below the level of high winds are dead weight, wouldn't it make more sense to just put a big tethered autogyro or 10 on the cable instead, and drive a generator from the prop rotation? This would eliminate the dead weight, replace the unstable kites with fail-safe autogyros that land gently naturally, and changes the requirement for a flexible cable that can cope with extreme tension for a requirement for a weaker less flexible cable that can transmit electricity, which should be easier to produce.
A pizza of radius z and thickness a has a volume of pi z z a
The winds do not blow the same direction as you go higher. Sometimes you get 90 degree shear or 180 deg shear. The poor kites will always be doing a shuffle to work correctly and efficiently between the low-level, mid-level, and high-level winds. I think that this plan is how he plans to get his pies-in-the-sky......
I remember when wind farms started generating controversy - mainly by those bothered by sight of them (see Kennedy's and the Nantucket Sound controversy). Those type of folks have paid obscene amounts of money to stop things like the Cape Wind project. Their reasoning (besides ruining their view of the sound in the morning)? It kills birds, it might change the climate, etc. Yeah... And what about the two coal plants that currently provide them electricity? In comparison, what do THEY generate?!
So when I see possible energy solutions like this one, it makes me rack my brains to think what excuse will these NiMBY folks use THIS time? Thanks so much for 'global stasis'. I can see the lawsuits now...
I vote for moving the coal plants in CT that feed Nantucket down near the Kennedy Compound. You might as well get them closer to where the HOT AIR is generated...
"...Well, there's egg and bacon; egg sausage and bacon; egg and spam; egg bacon and spam; egg bacon sausage and spam..."
If height is the issue, then why not have a tethered blimp hoist wind turbines? You could even cover the top of the blimp with flexible solar panels and have a high-flying hybrid system and you don't have worry about bombing people with a giant bicycle wheel if the wind died. If the weather gets bad just reel the blimp in.
Use the pancake rotor types, carbon composite blades, you could make some pretty high production turbines that were light enough to be raised by a blimp. Some kind of frame and the tether could double as the transmission cable.
That's our life, the big wheel of shit. - The Fat Man, Blue Tango Salvage
Oh no, not another wacko diversion from useful wind turbine design. I bet it'll make PopSci, just like all the other dumb energy things.
There was a similar idea to this about 20 years ago, called a "Lift Translator". It got goverment money. It made the cover of PopSci. It went precisely nowhere because it didn't work. This one's likely to work just as well/badly.
No-one I know in the wind energy industry thinks this 'laddermill" is remotely credible.
[On smoking]
Ishmael: You should try to quit. They say its bad for your heart, your lungs. It quickens the aging process.
Roy: Who's done more research than the good people at the American Tobacco Industry? They say its harmless. Why would they lie? If you're dead, you can't smoke.
"A few hundred"? That's at least 200, so we're talking about a minimum of 80,000, 27-foot kites, for a single large city. Then consider that each of these trains will be 5 miles long, and swaying in the wind. That means they need to stay some distance away from each other. My guess would be that half a mile between them (that's only 1/10th the length of a train) wouldn't be overly conservative. For a 14*14 installation (196 trains) that means just over 40 square miles (more than 25,000 acres) for a single installation. Sure, you can let some cows graze inbetween, but still. Somehow this whole scheme seems a little... impractical...
Catch a clue (or maybe just RTFA) - they're not talking about flying a single kite at 30k. They're talking about flying a whole stack of kites in a big loop. The only tension you need to worry about is from each kite to the next in the stack.
As long as each kite in the stack is capable of lifting its own weight plus the weight of the cable to the next kite in the stack, the "tension" on all of the pieces of cable will not necessarily accumulate from segment to segment. As long as it's engineered correctly, they could use strong fishing line as the cable (although that probably wouldn't handle the wear of going through the electrical generator ground station).
The overall tension will be whatever is needed to maintain the kites going up one side of the loop and coming down the other.
As far as safety is concerned, if you read more about their thoughts at www.laddermill.com, their ultimate intention is to make each "kite" a computer-controlled wing (complete with GPS). If the cables snap, the wings could control their glides down.
Actually, "industry" is only concerned with maintaining civilization and the environment to the BARE MINIMUM necessary to keep the masses consuming product. Industry can destroy and destroy, up to the point just before people can no longer consume.
I'd say at least in the USA, we have a long way to go before we hit the bottom.
As long as you have access to other countrie's resources.
Reminds me of a short novel published in an early 60s Analog by Walt and Leigh Richmond (which may have been called "Shortstack").
A lone genius move out into an arid southwest desert and quickly bulldozes out an underground home. He then feeds one end of a roll of sheet plastic into a jig that turns it into a very long tube.
After attaching some wire our genius somehow flies the entire (mile long?) tube up into the sky like a kite, and fastens the bottom end to a rig on the ground.
The air near the earth being relatively warm rushes up the tube, stiffening it. The resulting current turns a fan blade, powering an electrical generator.
Condensation along the inside of the tube constantly trickles down and provides all the water our hero needs.
I think he gets the girl.
Several groups have been studying hanging kilometer long wires from satellites to generate energy for the satellite or space habitation. These operate on the same principle: exploit the electric field gradients in the earth's magnetosphere.
Several orbital experiments have been tried. I recall one time mechanical problems prevented full unwinding of the cable. Another time the cable shorted and burnt apart from a power surge. I suspects these bugs will be eventually fixed by the engineers.
I've heard suggestions like this many times. My main arguement is that we should consider how tapping energy from the atmospheric layers above the Earth may impact our global ecology. Would it pull more dust from space, creating heavier Coronal Mass Ejection saturation? Would it have any impact on the geodynamo? As wonderful as were the ideas of Nikola Tesla (who was among the first to consider tapping the atmosphere for electrical power) it is important to give these ideas thorough review.
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-shpoffo