From the Carnegie Institution , some lofty ideas. Would you imagine a steady energy supply coming from high altitude kites?
Enough wind to power global energy demand
Washington, D.C.— There is enough energy available in winds to meet all of the world’s demand. Atmospheric turbines that convert steadier and faster high-altitude winds into energy could generate even more power than ground- and ocean-based units. New research from Carnegie’s Ken Caldeira examines the limits of the amount of power that could be harvested from winds, as well as the effects high-altitude wind power could have on the climate as a whole. Their work is published September 9 by Nature Climate Change.
Led by Kate Marvel of Lawrence Livermore National Laboratory, who began this research at Carnegie, the team used models to quantify the amount of power that could be generated from both surface and atmospheric winds. Surface winds were defined as those that can be accessed by turbines supported by towers on land or rising out of the sea. High-altitude winds were defined as those that can be accessed by technology merging turbines and kites. The study looked only at the geophysical limitations of these techniques, not technical or economic factors.
Turbines create drag, or resistance, which removes momentum from the winds and tends to slow them. As the number of wind turbines increase, the amount of energy that is extracted increases. But at some point, the winds would be slowed so much that adding more turbines will not generate more electricity. This study focused on finding the point at which energy extraction is highest.
Using models, the team was able to determine that more than 400 terrawatts of power could be extracted from surface winds and more than 1,800 terrawatts could be generated by winds extracted throughout the atmosphere.
Today, civilization uses about 18 TW of power. Near-surface winds could provide more than 20 times today’s global power demand and wind turbines on kites could potentially capture 100 times the current global power demand.
At maximum levels of power extraction, there would be substantial climate effects to wind harvesting. But the study found that the climate effects of extracting wind energy at the level of current global demand would be small, as long as the turbines were spread out and not clustered in just a few regions. At the level of global energy demand, wind turbines might affect surface temperatures by about 0.1 degree Celsius and affect precipitation by about 1%. Overall, the environmental impacts would not be substantial.
“Looking at the big picture, it is more likely that economic, technological or political factors will determine the growth of wind power around the world, rather than geophysical limitations,” Caldeira said.
Now imagine what a couple of thorium reactors could do…
Now who woulda thunk !!!!
Dutch astronaut and professor at the Delft University of Tenhnology Dr. Wubbo Ockels designed the Kite Power and did some encouraging experiments recently.
See his website for more details: http://www.kitepower.eu/home.html
Pie in the Sky !
A fantasy based on “computer models”
IIRC at Kitegen’s altitudes the wind always blows
The point about high-altitude winds is that they always blow.
No-one has yet built a kite that can get up there and then work reliably but that is a technical problem; it is not a fundamental flaw in the concept.
Don’t mix up the low level wind turbines (which do need the winds to be “just right”) with the jet stream.
These kites aren’t (yet) proven to be able unworkable.
This takes science fantasy to a new height.
So if the wind doesn’t blow, these things crash to Earth and if it blows too hard, these things crash to Earth.
Only ‘climate science’ could come up with a scheme which might work 250-300 days per year and be completely useless/tangled wreckage for the rest of the year – and just how do you get the energy to surface? A nice big, heavy, copper cable?
How much does the cable weigh?
..my last being a joke for regulars of numberwatch. Seriously, you can have kite power with the generator at the ground level, but that is not a turbine as mentioned here. Pipe dream, anyway. Any mentionof how the winds are affected? Doesn’t this screw up natural circulation?
I thought for one moment it was 1 April. Who monitors these clowns?
Jeesh – They really don’t know when to give up do they?
It’s not as if this cockeyed idea hasn’t been torn to pieces so many many times before.
http://www.numberwatch.co.uk/2007%20September.htm
Why won’t these academics in their mathematical towers ju st tell us ONE thing:
“How much does the tether weigh?”
Do the maths. Then go back to sleep.
OK, here we go again: the debate about how much wind energy truly can be harvested is far from settled science. Typically people assume a bottom-up approach: calculate how much wind can be generated by a turbine, expand the number of turbines – with assumptions – to come up with harvestable energy 100 times current energy demand. However, it appears that new insights suggest that far much less wind energy can be harvested that generally assumed. Top down approach: there are physical reasons why the wind blows, and you cannot simply “stop” wind from blowing by trying to extract energy. As a result, if you put an obstacle in the path of the wind to try to “stop” wind from blowing it will simply go around the obstacle.
Furthermore, the demand on area for wind in particular is staggering if it is to contribute to significantly to global energy demands:
“For wind-derived electricity, 17 TW represents approximately 319 million 2.0 MW turbines equally distributed over an area equivalent to 5.5-times the continental United States. For photovoltaic-derived electricity, 17 TW represents a coverage area equivalent to 4.4% of the continental United States. ”
Funny enough, this work seems to be largely overlooked, as evidenced by yesterday’s Nature Geoscience paper:
http://www.sciencedaily.com/releases/2012/09/120909150446.htm
http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1683.html
Geophysical limits to global wind power Kate Marvel, Ben Kravitz& Ken Caldeira, Nature Climate Change(2012)doi:10.1038/nclimate1683
References:
Solar and wind energy extraction within the Earth System – how are they related but different regarding power potentials and climatic consequences? Miller, L.; Pavlick, R. P.; Gans, F.; Kleidon, A. http://adsabs.harvard.edu/abs/2011AGUFMGC41D0849M
L.M. Miller, F. Gans, & A. Kleidon; Jet stream wind power as a renewable energy resource: little power, big impacts. Earth Syst. Dynam. Discuss. 2. 201-212. 2011. doi:10.5194/esd-2-201-2011 Final Paper
L.M. Miller, F. Gans, & A. Kleidon; Estimating maximum global land surface wind power extractability and associated climatic consequences. Earth Syst. Dynam. 2. 1-12. 2011. doi:10.5194/esd-2-1-2011 Final Paper
F. Gans, L.M. Miller, & A. Kleidon The problem of the second wind turbine – a note on a common but flawed wind power estimation method. Earth Syst. Dynam. Discuss., 1, 103-114, 2010. doi:10.5194/esdd-1-103-2010 Discussion Paper
http://www.bgc-jena.mpg.de/bgc-theory/index.php/Group/LeeMiller
http://www.earth-syst-dynam.net/2/1/2011/esd-2-1-2011.html
http://www.earth-syst-dynam.net/2/201/2011/esd-2-201-2011.html
http://www.earth-syst-dynam.net/3/79/2012/esd-3-79-2012.html
“Using models, the team was able to determine that ………. “.
Says it all, really.
Have they also taken air traffic into account? You’d have to clear large volumes of air space of air traffic to allow for stratospheric kites with ever increasing air traffic, requiring more space.
Pipe dreams of the idealists.
Firstly, who is going to ‘refly’ those kites almost every day, after they sink to the ground due no wind? Especially at coastal sites, this would be a very onerous twice-daily task – especially if they get tangled in ground features every time. (Can you imagine one of those draped across your roof each day, or smashing down your crops?).
Secondly, if you do manage to draw so much power from atmospheres circulations, what will happen to the weather? The high latitudes depend on cyclones (low pressures) spiraling up into the high latitudes and taking terra watts of energy with them. If you slow down and fill those low pressures (even if only by 10%), are you not going to inhibit their energy transfer capabilities?
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Ah, just go fly a kite… it should make aviation interesting.
This seems a lot more practical than offshore. Fewer maintenance problems, and lower construction costs.
If we are allowed to skip over technical and economic challenges – if you get all the rats in the world to run in generator wheels, you can supply half the US with energy.
Where’s my citation in Nature Climate Change?
Well, in its favour, it’s not as dumb as the flying turbine concepts that pop up every few years.
How many “terra-watt-hours” in a day, month, and year intervals, and (perhaps this a stretch) if we extract this energy from the atmosphere what will be the impact on climate and weather? They say “small” but can they guarantee the impact is less than alternative power generation strategies?
‘
If only we could power the world on wishful thinking alone!
Moonbeams and greendreams would fix all on our problems.
But back in Realityville…………
Could. I hate that word.
Among many problems with this idea I see one big one.
During the Second World War many nations facing bombing put up barrage balloons to force bombers higher and to snag any that flew low on the cables supporting them. I can see that these wonders of technology would have to be far away from any civil flight paths, which would count out most of the developed world. I know that if you look at a map of the UK with all the flight paths shown you can hardly see the land below and allowing for clearance around them there would be no room for error.
Don’t get me wrong I love flying kites but.
James Bull
Yeah yeah yeah,I think Kate is as high as a kite.Logically,there is enough heat in the sun to determine the temperature of the earth too.Isn’t there?Just go fly your kite to secure your funding.
Geophysical limitations, nothing technical using models. Perfect climate science. Expect some idiot politician to now say we can power the entire world with wind and if one questioned them they will call a denier of the science. It has gotten that bad.
It sounds like just more pie-in-the-sky to me They’ll never get these airy-fairy schemes off the ground.
Then there’s the problem of UV degradation of the synthetics used to make the sails and lanyards, and what happens when one finally lets go and gets tangled up in surface infrastructure or sucked into a jet engine.
Let alone pointing out that if you stopped the wind, then global warming would be horrendous, because you’ve stopped the convection engine.
Sounds like a lot of hot air to me! Leave out little things like “technology” & “economics” & you can do anything. I recall the anniversary BBC programme they did some years back now on star Trek, & they had a guy going over the physics of Warp engines & power generation, & the only fly in the ointment he could find was the little one of a world shortage of dilythium crystals!!! Anyway, a weekend of Red Dwarf was more than enough for me with Ace Rimmer accused of being as “about as butch as an ice-skaters friend”!
I thought that idiocy is the privilege of poor, corrupt and uneducated countries. The Carnegie Institution might consider strapping a belt around the equator, hooking it up to a generator, and presto! Free energy form the earth’s rotation (until it slows down and stops). Or install a big funnel and collect backround radiation from the Big Bang (that should last awhile).
@Martin Audley says:
September 10, 2012 at 12:53 am
“Jeesh – They really don’t know when to give up do they?
It’s not as if this cockeyed idea hasn’t been torn to pieces so many many times before.
http://www.numberwatch.co.uk/2007%20September.htm
Why won’t these academics in their mathematical towers ju st tell us ONE thing:
“How much does the tether weigh?”
Do the maths. Then go back to sleep.”
=================================================================
According to my post-normal mathematical calculations, IF we use superconductive unobtainium, the tether could possibly only be as big around as my little finger and could weigh as little as 0.027 grams per kilometer… maybe… if I remembered to carry the 2 and divide by the number of cats in Belgium.
If this imaginary world were to come to fruition then the requirement of near even distribution of wind turbines will cause greenie activists whine about wind turbine justice.
What’s a terrawatt? The SI system has a unit of measurement called the terawatt, I can only assume they are related. Whoever wrote the press release wasn’t too fussy about spell checking.
Very practical, first take 18 miles of high quality conductive cable, cut into 3 six mile lengths, and inset the triangular dividers at 2 yard intervals. Connect these wires to the turbine and the ground receiving station. Next attach the tether cable to the turbine ensuring that it is the specified one thousand ton breaking strain. Attach the kite in it’s self deploying module with the main switch in the safe position.
Next using appropriate lifting gear, place the turbine on the launch rocket, being careful to latch it correctly for self deployment. Double check that all cabling is laid out as per instructions to prevent tangling. You are now ready to deploy your life time guarantee 500MW wind turbine into the jet stream. What could possibly go wrong.
What about safety? I never read anything about that in this context.
The obvious technical solution is to build windfarms which have wind tubes which channel things like the jet streams to where their needed. To not upset the skeptics, they’ll be called wind canals and wind irrigation pipelines and high wind transmission lines so they’ll think it’s just a continuation of what we’ve already built for things like water, electricity, etc. After all, the skeptics still believe NASA still has that Moon landing warehouse tucked away in Area 51. They won’t even notice until we cover the planet. We’ll eventually enclose them into true tubes (which the Brit skeptics will think are subways) and put in a massive switching system. That way, folks that live in “skeptic land”, like the southern USA can just be blown off the face of the Earth. Then we can rename the Earth to what it should rightly be — “Terminus” — just like Isaac Asmov described in The Foundation series. Oh, and their names shouild be “Dylan Diverters” after this:
Now all we need to discover is where the food will come from but the Google chaps seems to have a handle on that one with their space initiative.
Don’t worry about the air traffic- there won’t be any when these clowns take over. It’s back to horse and buggy days. Backwards ho!
Ernest Lawrence is looking down on this in disgust. He was one of the few atomic founders who were NOT Soviet spies, and he worked hard to kick the Soviets out of the labs. Now it’s clear that our major labs have been fully occupied by saboteurs. They’re no longer working for Russia, but they’re still Soviets.
(However, the current generation of saboteurs are transparently ignorant and stupid, so maybe this is actually Lawrence’s revenge! Comrade Oppenheimer would never have wasted time on something as absurd as kite power.)
Bill Cody flew (?) on a kite, sitting in a basket. He did it by using a sequence of small to big kites to overcome the weight of the lines etc…but try to factor up to even a small turbine ?
And at what is the minimum turbine capacity needed to make it economically worthwhile…..you could end up with millions of these things…….blotting out sunlight…work out the shadow one of these would generate…..I could go on, but.
Consign it to the bin – if you can’t make a technical case then it’s not kites, it’s pie in the sky.
Niek Rodenburg says:
September 10, 2012 at 12:11 am
Dutch astronaut and professor at the Delft University of Tenhnology Dr. Wubbo Ockels designed the Kite Power and did some encouraging experiments recently.
See his website for more details: http://www.kitepower.eu/home.html
I thinks that’s impressive. Of course, if enough of these things were airborne to make really useful amounts of power for a town, the tether lines would tangle unless they were spaced so far apart that you’d soon encroach on the neighbouring towns ‘airspace’, but still, it might work for a remote farm with no power grid near to it.
Can’t see them being popular with aircraft pilots though.
Disentangling the tether from the countryside/cars/power lines when the thing comes down might be a challenge…
Still, some clever automation and development of in flight reliability might minimise that.
A much safer and technically feasible alternative is powering civilistion with hamster wheels.
My model shows that you can generate all of the 18 TW of power with 14 hamsters and a sufficient number of wheels per square meter.
Assumptions:
1 Hamster averages 0.009 W (source: instructables)
Earth has 148,940,000 km^2 of available land mass.
No high strength cabels, stacking of hamster cages or other unproven technology involved. There is a problem of intermittancy, but that can be solved by averaging the output of large numbers of hamster wheels with a transcontinental grid as envisioned by Buckminster Fuller or Technocracy Inc.
I think they mean 100 metres off the ground as “high altitude”. Slightly higher winds- no more reliable.
“The point about high-altitude winds is that they always blow.”
Not always. Check the plots every day for the next few weeks: http://weather.unisys.com/upper_air/ua_const.php?plot=30k&inv=0&t=cur&expanddiv=hide_bar You will see that where there is an upper ridge (or sometimes an upper low), the wind stops. Then it may reverse direction. This idea is about as lame as offshore wind, very expensive and unreliable.
Lot of mention of circulation patterns etc. I would think the “Butterfly effect” to be much more powerful. Tap into the jetstream with kites and who knows what will come of it. A small nudge here, another there and soon enough it will be sunshine in Seattle, and snow in Miami.
Think of the lawsuits! Think of the potential of weather control…
The Chu DOE is already funding this lunacy…..Makani Power of Almeda is one of the kite money pits….ironic that the promoter of this kite marvel is “Kate Marvel” ! ! !
Elitist owned Pop Sci [Bonnier] and Pop Mechs [Hearst] are all over this ‘technology’. More at
http://www.sfgate.com/news/article/Inventors-high-flying-kites-harness-wind-power-3211762.php
There’s lots of wacky ideas about using wind or solar or tidal power to fix the woes of the world, but I thought it had been pretty well demonstrated that you could offset more emissions and generate reliable power from installing Combined Cycle Gas Turbine power stations. Wind will always require baseload power in the event that the wind stops blowing.
Here’s a thought – what happens when one of these things gets struck by lightning?
Eric (skeptic) says at September 10, 2012 at 3:42 am that the winds are not always blowing at high altitude. Good point. But they are a lot more reliable than downlow.
The Dutch guy whoi has bee linked to claims his kites already double operating time and as the materials are a lot cheaper than turbines it is not acceptable to just ignore the possibility.
Technology is good.
http://www.kitepower.eu/technology.html
Aslo, not that the generator is on the surface. There is no copper cable in the sky. The rope sails up and then glides back again with the motion converted ot electricty on the surface. is website says it can be used at sea so that may mitigate the justiifable aviation fears.
I’m just suggesting that new technology shouldn’t be rejected before you’ve done the sums and the experiments.
I think there must be some kind of wacknoodle underground contest going on to see who can come up with the most insane and unworkable concept/study. It’s difficult to see how proposals like this one can do anything but elicit gales of laughter from the authors and their associates.
Wouldn’t it make much more sense to try to capture the electricity from lightning?
There is a plethora of it world wide.
http://geology.com/articles/lightning-map.shtml
It would be as likely to be successful as the wind/kite silliness.
/sarc/sarc/sarc/sarc
Sillier than windmills.
Starts at about 2:50
Almah Geddon says:
September 10, 2012 at 2:49 am
What’s a terrawatt? The SI system has a unit of measurement called the terawatt, I can only assume they are related. Whoever wrote the press release wasn’t too fussy about spell checking.
Perhaps they meant a terrorwatt, as that is the most likely (95%) outcome. I for one would be terrorised about one of those infernal things coming down on me when thery eventually fail, not that any sane person would commission such a scheme! 😉
[Would that be “when theory eventually” fails? 8<) Robt]
“Using models, the team was able to determine”
So now it’s models all the way…up?
I have no objection to people doing the thinking about these things, just how much they get paid for it, and their abilities to filter out the worst ones.
Flying another kite… How about using electrolytically generated hydrogen [from water] in a balloon to support the weight of the kite/tether at locations/times when wind is insufficient, and provide energy storage? At least these ideas have the merit of being testable at relatively low cost, and don’t ask for the world economy to be disrupted to the tune of some trillions of dollars.
Compare with one idea mentioned at Judith Curry’s blog where somebody proposed building windmills in Antarctica to condense CO2 from the air and bury it in a hole in the ground. [Yes, what ground? And no, I won’t make the obvious crude joke]
This somewhat more “down to earth” approach seems to be promising.
http://www.makanipower.com/why-airborne-wind/
I never held out much hope for wind power before seeing this. But to this somewhat non-technical layman this looks like it holds promise. Or is it similarly plagued by needing too many in any one area to be practical?
Put advertisement on the bottom of the kites to help defray the cost. Paint the top of the kites white, global warming solved. I am surprised they have not thought of this.
/sarc
One word: maintenance costs.
That’s actually two words but what the hell, this is climate “science” so being inaccurate is acceptable.
The ultimate irony is when one of these get stuck on a transmission line tower. Josh?
thallstd
It`s Bollocks,i suspect you knew that already;)
Good luck to Makani Power – if, as a private company they can develop a saleable product, they deserve to prosper. After all, that’s the glorious thing about the free market – it’s a mechanism to discover which new ideas work.
But there’s are three big differences between their ideas and the academic discussion of the use of high-altitude winds:
1. Makani are engineers – not academics. To their eternal credit they are actually trying to build these things – not discussing models.
2. Makani are not spending _my_ money to find out!
3. Makani are planning to operate at 1000 feet – not 18 miles. The key question about high-altitude devices stands: What is the weight of the tether?
ps. Makani’a supposed “demonstration” of transition between hover and crosswind flight looked awfully like the device was being _fed_ power through its cable, rather than generating it!
and there’s enough solar energy hitting the planet to provide perhaps 1,000s of times the energy we need, if we could just build enough photovoltaic cells to capture it, but, this isn’t about technological challenges…
I love stuff like this.
I like the hamster wheel idea!
There are kites like this for ships. I don’t know the website I found it on, but these have been attached to cargo ships for a over year. I have no idea if they work or just make the ship look “green” and make great adverising.
If we really want to know if new energy ideas are feasible, we need a law that Washington DC must be powered by any new energy source for a period of one year before any funding can be given. It must be powered by that source ALONE, no backup. After DC, each senator and representatives home towns will go on the power for a year. If after two years, there are no riots in DC and the senators and representatives have not been recalled, then we talk subsidies. Wait–we won’t need them then because the energy source will really be workable.
I missed the part where they actually generate electricity.
_________________________________________________________________
I think you may have just hit on the “Combating Global Warming” aspect of this project. You see, by making all the kites out of highly reflective material and covering the jet streams with them, we can change the albedo of the planet and go ahead and enjoy the ice age we so richly deserve. Of course for this icy utopia to happen half the plants and animals (including humans) on the planet will have to die, but that is such a small price to pay for utopia!. (need I say /sarc?)
I suspect that there is enough power in the Sun to power human civilisation. Can I have a professorship, a grant and a team to investigate this?
Actually, there might be enough power in the world’s rivers and waterfalls. Especially if everyone saved energy. Perhaps I could investigate that later. And then go on to investigate the total energy expended by the world’s worm population….
Why bother to limit ourselves to wind balloons or kites? Why don’t we just run the world on the energy we can project from our heads? You know, stare at a lightbulb, turn it on; same with a car. Studies show it would take 100 people to keep a factory going–no lunch breaks. If wishes were horses, right? Bad enough the right and the left in the U.S. don’t even speak the same language anymore. Now we have fantasy masquerading as ‘theoretical.’ If this weren’t simply stupid, it would be funny. The necessary reading here is Jonathan Swift, Voyage to Laputa.
Never any shortage of people on the internet ready to open their mouths without knowing anything about what they are talking about. I’m an engineer (BE Mech ME Elec) and have been involved with the huge kites and kite traction all my adult life and know some of the people developing kite power systems. Though not personally involved I have to say that Kite power looks quite feasible – there is risk, but the payoff is huge, ultimately their cost of generation has a very good chance of being cheaper than anything else, including gas.
1/ There is about 20x as much energy flux per m² at 10km altitude as at typical wind turbine height, even more in Jet Stream, and it increases pretty consistently up to 10km height, though there are fastest gains in getting up to about 1000m (top of earth’s boundary layer). Winds are also more reliably strong so that will be able to generate power more of the time. Kites can sweep through that wind faster than a wind turbine blade meaning even larger power extraction for a given sized wing. This means huge power from small, lightweight kites/airborne turbines that are orders of magnitude lighter than ground based turbines, and that can make them massively cheaper once the autopilot and launch/retrieval issues are solved (flying kites is hard even for humans).
2/ Kites can scale up enormously – this is early days and most people are sensibly developing at cheaper kW – MW scale low altitude plants to debug, but ultimately there is technically nothing preventing economic GW scale units at higher altitudes once the bugs are worked out at smaller scales. Scaling up works very well due to the ability to increasing winds with altitude, and the proportional reductions in line drag with length. 1GW is about $50-100million of electricity per year.
3/ They can work very well in terrain unsuitable for wind turbines or off-shore with little more than a tethered floating base and with fewer 100MW-1GW units linking to grid is far cheaper than more numerous 5MW units.
In my opinion the Delft system is not particularly good, because soft kites lack durability and the carousel autopilots are very difficult. Makani and perhaps SkyWindPower may have better chance of working out, though only in larger scales than what they are working on.
So you admit it basically has to be kites have to be the middle of nowhere so the transmission costs will heavily bite into any power you produce.
I love it when “peer-review” is conducted by the common folk!!!
And just think of all the energy in the waves of the ocean and its currents and the movement of rivers. What about all the power in lightning, volcanoes, earthquakes, and static electricity?
And if we could only harvest the energy from people flappin their yappers!!
The use of kites to illustrate the concept reveals the fundamental ignorance of physics at the heart of this proposal.
A kite line may be able to exert a *force* (F), but no energy can be extracted from the force without requiring the force to do physical *work* (W) – i.e. move something through a *distance* (D): W = F * D.
The distances available for towing things along the ground with a kite are sharply limited.
There is enough wind energy to run all sea transport in the world. Now, I wonder why sailing ships disappeared from the world’s oceans.
Must be better to go back to sailing ships and horse carts. That’s what they want. A kind of Amish lifestyle with some solar panels and windmills, but you can’t use too much energy. Because energy use is the new sin.
With change of worship of course, instead of the bible a worship of mother Gaia.
Kites are silly. Just mount wind-turbines on the side of something useful, like a space-elevator.
/sarc for those that think this is practical….
It would have been really good if they had talked to a meteorologist or two, they may have realized that some of their basic assumptions were totally flawed. As to the problem of cables to height interfering with aircraft, kites coming down in populated areas when the wind stops or reverses, tangles of power cables in an urban setting. It is immediately apparent that these people are not engineers.
“the team was able to determine that more than 400 terrawatts of power could be extracted from surface winds”
Over what area? The whole of the Earth’s surface? (In which case the realizable total will be somewhat less that 400TW) At what efficiency?
Mike.
Fess up. Which one of you told a warmist to, “Go fly a kite!”?
Has anyone thought about the effect of taking this natural wind effect away from the rest of the ecosystem?
thallstd says:
This somewhat more “down to earth” approach seems to be promising.
http://www.makanipower.com/why-airborne-wind/
I never held out much hope for wind power before seeing this. But to this somewhat non-technical layman this looks like it holds promise. Or is it similarly plagued by needing too many in any one area to be practical?
I would think building one should be difficult enough for anyone. Remember that what is suggested is essentially to build an aircraft that is capable of flying essentially for ever, in storm, rain, hail and icing, guided by an autopilot that apparently never fails (the first one ever, by the way). This autopilot controls the aircraft and flies it in circles which means it must have ailerons and rudders, operated by (presumably) electrical actuators, which never wear or fail (also an all time first). Also this autopilot must have control laws that can cope with a wide variety of wind speeds, sudden gusts and changes in wind speed. It would realistically also have to be capable of bringing the aircraft in to a controlled dead-stick landing at a pre-determined spot either tethered or free-flying irrespective of weather when something goes wrong (which it will, most likely in bad weather).
But perhaps it is never calm where it is flying and the aircraft never needs any maintenance, and nothing ever goes wrong, since it has no visible landing gear (or it might have retractable gear, greatly adding to weight and complexity).
Having 40 years experience of aircraft and aircraft maintenance my opinion is that this is indeed a “down to earth” idea in the most literal sense.
tty… if you watch the video of their test flight (http://www.makanipower.com/category/flights/) it seems that a lot of what you indicate is needed either isn’t (maybe because it’s tethered and not free-flying?) or has already been accomplished (not to say it doesn’t need improvement) or the entire video is a fake. As for landing, once in operation it is housed on a small tower and never touches the ground so traditional landing gear and auto-logic is not needed. Not to say that there aren’t any number of things that can go wrong and long term maintenance is certainly to be factored in. But at some point we need to develop additional sources of energy and these folks are, as someone above pointed out, at least attempting it with private vs public funds. I wish them luck.
Paragliding stocks up this morning…
Obviously these things are sufficiently dangerous they will cross their own power lines which requires they have buried power lines anywhere in a circle defined by the length of the tether. Here is a logical feasibility test: Can these things be made to work unattended at sea? What is the recovery time for redeployment after a crash in a rain-soaked field? What is the compensation plan for when these systems crash across freeways or highways or railways, blocking traffic? What is the cost of unraveling the shrouds? What is a grant worth to study this trash?
Lot’s of kites blocking the free flow of wind could alter the climate in some modelably catastrophic way.
There, I’ve CAGW’d the proposal.
Will that not speed up the earth’s rotation? Just think, we could get twice as many days in a year.
@Rob L
I’m not an engineer (neither BE Mech nor ME Elec), so I still wait for you to tell me what the tether will weigh. Specify any cross sectional diameter, any material, any conductivity, and any dielectric constant for the insulation that you like (remember we’ll be talking around 25-30 miles long for a kite flying at 18 miles altitude. I’ll wait…
Won’t this daft idea speed up the earth’s rotation? Just think – twice as many days in a year…
tether weight is the limiting factor. this is a well known problem with anchoring boats in deep water. For example, a steel cable will break under its own weight if it exceeds 10 miles in length,
Rob L says:
September 10, 2012 at 6:19 am
While (as a mechanical engineer also) I don’t disagree with any of your technical points, what happens when a thunderstorm comes along? And what happens when one of these kites breaks loose and crashes into someone’s home or business? Seems like a lot of trouble to harvest energy which can be more easily be obtained and distributed (on a large scale) from other sources (e.g. coal, nuclear, and natural gas).
This is like debating the scientific accuracy of something from The Onion.
Being a free market capitalist, I encourage those who believe in this to invest their own money in R&D. But if you expect the government to fund this with taxpayer dollars….well, let’s just say “them’s fighin’ words.”
Fun fact: In gliding sports, the life-time of a glider is essentially directly related to the fabric’s sun exposure time. That’s why you don’t wanna mess around for hours when not flying — you pack it up immediately. And depending on how much hours you did, you might want to sell it off on Ebay after 2 seasons, because tehy lose air-tightness… With all day sun, every day up there, you can replace those kites every 3 months, hahaha (read: they not gonna be good for 3/5/10 years)
Having 40 years experience of aircraft and aircraft maintenance my opinion is that this is indeed a “down to earth” idea in the most literal sense.
How about looking at what Makani propose before you start criticising, I can assure you they are extremely talented engineers (having met a few of them).
They are rigid, durable, carbon fibre wings flying in loops, so very little control input required, and they actually achieve all the necessary control by simply modulating the drag from the multiple turbines distributed above and below the wing across its span.
With those same multiple turbines working as propellers have already demonstrated VTOL lift off and recovery back to their base station, as well as looping flight all under autopilot control.
They have power available to deal with loss of wind, they just stop generating and start using power to the props to stay aloft during a lull and can hover as they are pulled back to base if wind drops away too much to produce power.
They can slow the looping or even stop it if the wind gets too strong (but the kite flies at 70-100kt so winds are realistically never too strong).
They can ultimately have redundancy in the turbines to allow landing after one fails – like multicopters, There is also potential for autorotation with pitch control or even carrying some battery backup at ground and/or on the kite.
They can be landed when lightening threatens.
Their proposed 5MW wing can produce several $million in electricity per year, is about the same size as a single blade on a 5MW wind turbine, weighs probably 3-5 tonnes, and could probably be replaced every year and still be profitable (though I doubt it would need to be). $500/hour in electricity can pay for a lot of maintenance.
A.k.a turbulence
Why not? There are both economical and energy (great) issues to get this stuff into the air.
Also, there is an extra cost and loss of energy involved every time needed bringing them down before lightning/thunder storms and afterwards, when they are going back up again. (Reminds me of all the erroneous wind turbine calculations …) This also applies when the wind is not able to keep the kite in the air.
Rob L. and anyone else suggesting this idea. The problem is not technical. It is weather. You stick kites 5-10 miles up, by the thousands, you will alter weather patterns. You might only shift things a little where this power station is located, but thousand miles down wind, there is no modeling that can tell what will happen. If you disrupt weather for years, you create climate changes.
If you don’t agree, what does mountain ranges do? Look at the weather patterns down wind from these, and you will have the basics of what these kites will do.
Here is another example, take a wind tunnel, introduce a small obstacle, and watch the change through out the whole tunnel. Very little will do a whole lot.
Here on WUWT there were pictures of the “contrails” behind wind turbines. Not a big issue at ground level. Bad idea in the sky. I bet due to the wind slow down caused by a few thousand of these, you will trigger increased rainfail right behind/infront these farms. As the wind slows down, clouds pile up, just like waves crashing to shore. Place this in the wrong place, and you will have a desert 500 miles down wind.
Worse, set these offshore and a whole continent will see reduced rainfall.
The disruptions will be massive.
Interesting idea, but first you need to do some homework in fluid mechanics …
Flow through tubes requires optimal conditions, if it should be useful:
* Length and cross section area is of great importance for this. Since wind speed is a variable in the context, length and cross section area must be adjusted accordingly … (Ooops! Try that one in a simple construction, as the wind is constantly changing in speed …)
* All existing objects that are inside the tube reduces efficiency by turbulence, including turbine units. There are better and more controllable medium available than air! (ie. water, see below …)
* All bends reduce the flow. Reducing this problem requires a rotating device which can follow the wind. If the pipe is large enough, motors for rotating are required because of the mass … (requires power … a contradiction!)
* Turbulence also occurs in straight tubes, unless the flow is at the right speed. Control via ports does not help in this case, as it increases the flow resistance (compare with a silencer, which require adaptation to ammunition performance to be effective, but in this particular case the “flow” is regarded as a constant.)
* The density (mass) of what is flowing through the tube matters! The lower the density (mass), the easier it is to reduce flow. This is why water is more suitable than air for the purpose …
Your quick thinking reminds me of the young guys who think they can be easily and in a relatively inexpensive way to get more power out of a car engine. This by replacing the exhaust system with a larger one. If not pure luck, wrong! The consequence is rather higher noise and increased engine wear (piston rings, gaskets and expensive things like exhaust valves and valve seats …) and probably a disapproval at the annual national controlled vehicle inspection (noise and/or difficulties of measuring emissions). On most vehicles, the end pipe must be located at the rear of the vehicle. This limits (prevent) the possibility to shorten the total length of the exhaust pipe, to adapt to the enlarged cross section of the exhaust pipe. (Changing stuff like this on newer cars sold within EU, is not legal according to the WVTA (Whole Vehicle Type Approval), without a direct (ie. written) approval from the manufacturer …)
The trouble with carbon fibre is it has a shelf life and whilst very strong in certain design parameters is ultimately not very durable, I think some serious material design technology evoloution is required before these kites can become an every day reality, quite apart from the effect large numbers of them will have on the climate. If CO2 in its very small concentrations can have such an effect on climate, according to ‘the experts’ of funded climate science; logically the same thinking can be applied to perturbations in the upper atmosphere wind streams.
I bet the contrails of a thousand of these would be a sight. Not only from the kite, but also from the wires. Think of “Von Karman cloud vortices ” off of islands. I bet there will be a few environmental lawsuites.
More kids playing with toys, funded by my tax dollars.
“Led by Kate Marvel of Lawrence Livermore National Laboratory, who began this research at Carnegie, the team used models to quantify the amount of power that could be generated from both surface and atmospheric winds.”
Maybe Kate is a Marvel comic heir, carrying forward the family tradition.
Hello, I’m a kite minder. My job is to run and relaunch the kite. Unless the tree eats it.
“The study looked only at the geophysical limitations of these techniques, not technical or economic factors.”
This is not a study. This is a paper napkin calculation shoved across a table down at Morey’s for the amusement of a few academics, one of whom will promptly set a beer glass down on it.
“Looking at the big picture, it is more likely that economic, technological or political factors will determine the growth of wind power around the world, rather than geophysical limitations,” Caldeira said.
Duh.
Studies indicate that there’s enough energy in the squirrels of the world to power California—if only we could figure out how to get them all into those little, spinning cages and hook up all the tiny, squirrelly generators to the grid.
One problem not yet discussed is icing. I can envision the kites getting loaded up with ice. People will be very unhappy to have hail stones the size of aircraft crashing around or on them.
Rob L says:
September 10, 2012 at 6:19 am
How do the de-icing/anti-icing systems work on these high flying kites?
Here is a funny calculation. found a claim “http://www.ecomagination.com/the-power-above” claim up to 10kW per sq meter in the jetstream. Lets say they harvest half. so 5kW per sq meter. 200sqM for a MegaWatt. 200,000sqM for a GW. 200,000,000sqM for a TW. 2800 Sq Kilometers for all energy we need, 14 TeraWatts. So, a WALL, approximately 3000 feet tall and slightly short of 2000 miles wide, in the sky, slowing down the wind by half….
Did I do that calculation right??
If I did, that would constitute a massive impact on our climate. That is a brand new 2000 mile long mountain range, just to prevent a lousy estimated 0.1 Celsius temperature impact by CO2.
Here is a question that no one seems to have ever considered.
The green power activists are all very concerned about CO2 and man’s potential impact on climate.
But what about the potential impact on climate of “green energy” removing so much energy from the climate system?
If we were to truly able to meet our global electrical power needs by wind power and solar power, would this not result in a great deal of energy being removed from the climate system when it is converted instead to electricity?
How important is the role that wind energy plays in the climate system and what impact will removing a large amount of this energy from the climate system?
Also if a large amount of solar energy, which is constantly needed to keep the planet from becoming a cold rock, is converted to electricity instead of heat, and on the scale required, what will happen to the average global temperature?
There seems to be some unstated assumption that solar and wind energy is infinite and removing a large chunk of this energy will have no impact on climate.
Are the green energy activists courting doom for our climate? I do not think their plan is well thought out nor do I think that they understand the climate system well enough to be able to make informed conclusions on these questions.
Regarding SasjaL says: September 10, 2012 at 9:19 am
Check out the definition of satire when the fluids drain out and the internet is up again.
I’m quite astounded by the lack of any intellectual rigor in nearly all the 97 comments I have read so far: willful misreading of the article, simplistic objections, and willful lack of imagination in overcoming them. Only one comment gives a sensible appraisal of what is eminently achievable for producing a proportion, however small of our energy needs. Not one comment has acknowledged what we all know- that if the wind drops, the kite can be reeled in and the speed of that reeling in can ensure its maintaining altitude until it rests on its base. No tangling, crashing into power lines or demolishing buildings. What’s more, being anti warmist doesn’t preclude a desire for pollution-free energy. For this reason, the posting of this article is off-topic with regard to challenging the warmist agenda.
@ Scute: Do you have any specific objections to any of the criticisms posted here or just one long ad hom against everyone who posted? I take it also that you will be out lobbying for nuclear power today, since you are so keen on non-polluting energy sources?
Scute says:
September 10, 2012 at 11:17 am
“Not one comment has acknowledged what we all know- that if the wind drops, the kite can be reeled in and the speed of that reeling in can ensure its maintaining altitude until it rests on its base.”
So how far in advance of the squall line do we need to start “safely” reeling in the kites? I see a massive fail during the first bad weather event…
(p.s. For testing purposes, let’s station those kites over your house or place of business…)
First: They used models.
Second: They were not bound by normal rules of physics.
Third: What they propose is pure optimism.
I was trying to decipher where the solutions to the significant technical challenges to this solution are defined. Finally it dawned on me, this is an article out of “Popular Mechanics” and gussied up by imaginary assumptions about just how much power might be possible from a column of air.
Another fantasy for the big AR5 and the future of climate funds.
Other than being a nasty and accusing others of faults you display all so well. Can you answer any of the big tehnical issues?
What happens when:
The wind stops, not slows down, stops? Even if for just a few seconds (not unusual). Even kites, especially kites with turbines are subject to that dratted 32ft per second squared. Most pilots dread an unexpected stall, and that’s with a plane they’re in control of.
The wind goes into a tight circle? Think tornado, but even a storm front can cause this.
Sudden wind direction changes? Downright common.
High altitude dust? Volcanoes and sand storms do more than play havoc with planes that can avoid them.
Wing span necessary for high altitude flight? Without power the wings must do all of the work holding that turbine. That needs significant wing area, even if you’re only putting a miniscule turbine up. The bigger the turbine, the more massive the wings and supporting superstructure.
These are just the quick ones off the top of my head as I was wondering how they were deciding they could shade so much of the land below. I am also curious how much electricity must be available to reel those suckers in, just in case or for any reason.
Now about the intellectual rigor of your comment…
rogerknights wrote:
“This seems a lot more practical than offshore. Fewer maintenance problems, and lower construction costs.”
I’ve got to go with Roger and against the naysayers on this one. I think the idea has promise.
Kites would be a lot more versatile than turbines: you can vary the height to catch the strongest wind; you could even move them from place to place to take advantage of seasonal variations or follow the jetstream and they would be much easier to remove if they don’t work out. It is worth some further research at least.
Leave it to private industry. If it’s economically viable, they’ll do it. And if some corporation just wants to green their image by sponsoring it, that’s fine with me too.
Bill Illis wrote:
“I missed the part where they actually generate electricity.”
Watch the video linked to by banjo (although he appears to be dismissive). The energy is gained when the kite is being pulled up and along by the wind, turning the cable drum. There is not the same resistance when reeling the cable in, if you tweak the aerodynamics of the kite. If you had several kites aloft in the jetstream some can be being let out (generating electricity) as others are being reeled in.
But keep your kite aloft in a thunderstorm and you’ll have more energy than you bargained for coming down that cable.
Thallstd says:
“tty… if you watch the video of their test flight (http://www.makanipower.com/category/flights/) it seems that a lot of what you indicate is needed either isn’t (maybe because it’s tethered and not free-flying?) or has already been accomplished (not to say it doesn’t need improvement) or the entire video is a fake. As for landing, once in operation it is housed on a small tower and never touches the ground so traditional landing gear and auto-logic is not needed.”
Actually in that video you will note that the test aircraft has a (fixed) landing gear, it has ailerons and rudder (and apparently a separate elevator, which I thought might have been eliminted by using the ailerons as elevons, but apparently not).
Also note that it apparently took five years development work to get the the autopilot to the point where it can make one autonomous crosswind turn.
As for the autopilot not having any capability to make untethered landings, sure it will work in a way, but it means that every time the tether breaks or the wind strength goes below stalling speed an aircraft will be lost.
And I can assure you that there is a world of difference between brief test-hops in perfect conditions to continuous operations in all weathers. Going from one to the other took rather more than a generation for ordinary aircraft.
Replying to many:
Not sure about icing, but can’t see how it would be a problem. Not a problem for cable due to resistive heat, and can’t see how heating systems would be problematic on wings. Could also just change altitude or land.
Cable weight is a relatively minor issue, a 15km long IM10 Carbon Fibre cable that can support 1000 tonnes with factor of safety of 2 weighs 100 tonnes and is about 80mm diameter Weight is proportional to length. And the conductor embedded in the cable doesn’t add much weight or size at high voltages. Line drag is a problem (will generally fair the line) – but scales up with kite size, so if works at 600m with a 5MW kite then it will work just fine at 10km with a 1GW kite.
The Makani system isn’t the only way of doing things (or even necessarily the best in the opinion of myself and some other people in the know) – can also use lighter than air to support some or all of the kite and line weight. at higher altitudes, or use many kites distributed over the length of the line. Again something that works best in GW sizes.
Carbon fibre is very strong over the long term as long as it is not subjected to changing stresses (fatigue), for proof of this look at energy storage flywheels. The nature of the loading on a kite on a long line is such that the tension remains very consistent due to elasticity of the line and light weight of the kite+line compared to lift – so not much fatigue.
In article they state worldwide wind power 1800TW, extracting a few TW is not going to be a problem for climate, and at 10km altitude won’t even notice it at ground level – whereas thermal power stations do produce noticeable local effects.
A lot of posters on this thread seem to be arguing at cross purposes.
The article is about a parachute type kite that generates electricity at ground level by turning a cable drum.
Makani Power of Almeda, which so many commenters seem to be referring to, propose an aircraft type kite with a turbine that would generate electricity at altitude that would then have to be transmitted down the cable.
The first idea is the simpler of the two and I think potentially feasible.
Here is a funny calculation. found a claim “http://www.ecomagination.com/the-power-above” claim up to 10kW per sq meter in the jetstream.
Umm … At 30,000 feet and -40 centigrade the density of air is about 0,45 kgm-3. To produce 10 kW per square meter would require a wind strength of about 210 m/s or about 450 mph, that is nearly twice the highest wind speed ever recorded in the jet stream and therefore about three times the maximum energy density (since energy is proportional to the square of the wind velocity).
Incidentally it is physically impossible to extract more than about half the energy from wind.
Global warming supposedly produces more wind , so we should therefore keep burning fossil fuels. Alternatively we could cover the planet with black plastic “cling film” in order to absorb all that extra “back radiation” for power production !
“Umm … At 30,000 feet and -40 centigrade the density of air is about 0,45 kgm-3. To produce 10 kW per square meter would require a wind strength of about 210 m/s or about 450 mph, that is nearly twice the highest wind speed ever recorded in the jet stream and therefore about three times the maximum energy density (since energy is proportional to the square of the wind velocity).
Incidentally it is physically impossible to extract more than about half the energy from wind.”
you forgot that the amount of mass flowing through that square meter is proportional to the velocity too. So velocity is more like 35-40m/s = 70-80kts, 125-144km/hr ie about right for the jet stream.
I agree with the concept. But, as usual, when the rubber hits the road, the concept evaporates.
What is the EROEI for this wind power proposal? In absence of an answer, assume < 1. It is unsustainable.
“High as a kite with a buzz” is the slogan for soliciting stoner funding.
Ask anyone who has operated sailplanes in a winch launch operation about the practicalities. There’s a reason towplanes and motor gliders are desirable!
Maybe we could harvest all the Ch’i energy found in Feng Shui in our homes! Wind mills could be placed in sharp angles in hall ways, and the Ch’i extracted in that way. First computer models should be run to determine the maximum level of power extraction.
As for harvesting energy from high altitude winds, we could just hang the wind turbines from clouds.
“Today, civilization uses about 18 TW of power … ”
Whoa. That’s *primary* power power – all the energy including heat energy going in the front end of power plants, combustion transportation, etc. Wind electric power does not have to play that game. That is, a coal plant producing 1GW thermal can be replaced with 300-400 MWe average wind, intermittent output issues aside for a moment. Space heat and the like use direct heating, but I think the total worldwide *secondary* power load is more like 11-12 TW, with room for less still to the extent space heat is accomplished with heat pumps instead of direct heat.
“It is weather. You stick kites 5-10 miles up, by the thousands, you will alter weather patterns.”
During any given daylight hour in the US there are some three thousand large body jet aircraft 3-5 miles up. Has this altered the weather?
I don’t mind pie in the sky brain-storming coming up with completely useless and unworkable ideas – except when I have to pay for it. The House needs to hold hearings on who authorized funding for this study and who permitted Federal resources at Livermore to be devoted to this “work”.
“””””……M Courtney says:
September 10, 2012 at 12:35 am
The point about high-altitude winds is that they always blow.
No-one has yet built a kite that can get up there and then work reliably but that is a technical problem; it is not a fundamental flaw in the concept.
Don’t mix up the low level wind turbines (which do need the winds to be “just right”) with the jet stream.
These kites aren’t (yet) proven to be able unworkable……”””””
So If you tether one of these “kites” (what a thought), and then you start extracting gigajoules from it, something in my Primer 1 Physics book, says there is going to be a reaction on the kite, like a big shove. I suppose that eventually the kite string will lay out in a catenary shape.
My schoolboy experience with flying kites, to some whacking great heights; well into the illegal aircraft inhabited range, says that catenaries are pretty damn big and horizontical for a long way, when the kite is that high. I seem to recall dropping such kites on the farm house way down the road. But in those days we didn’t fly a 10 megaWatt turbine on our kite; well we were too poor to afford one; otherwise, I’d a done it.
It’s also good that the wind direction doesn’t change. We used to tether our kites to the barbed wire fence, and go home for the night. Quite often, the next morning it would have crashed on the farm house up the road, instead of the one down the road. Who knows what it would take out while rotating during the night.
At least when you anchor a boat, you can put out two anchors to stop the boat from sailing up onto the beach.
They did say there were some bugs to work out didn’t they.
Personally, I’m much more a fan of the tethered geo-synchronous satellite that holds itself up without wind, and pipes down a lot of solar electricity.
“””””…..Rob L says:
September 10, 2012 at 1:36 pm
“Umm … At 30,000 feet and -40 centigrade the density of air is about 0,45 kgm-3. To produce 10 kW per square meter would require a wind strength of about 210 m/s or about 450 mph, that is nearly twice the highest wind speed ever recorded in the jet stream and therefore about three times the maximum energy density (since energy is proportional to the square of the wind velocity)……”””””
Well not exactly. The wind drag force goes as the square of the wind speed, but the power goes as the cube so the energy would go about at least the cube of the wind speed. That is in fact the beauty of wind power. If the wind speed drops to half of your design operating wind speed, you lose 87 1/2 percent of your generating capacity.
But if the wind speed doubles, you get eight times the power but the whole thing blows up anyway, so you actually end up with zero.
Wind is an ideal energy source, you can get winds from zero to 150 mph or even 250 in a tornado, whereas with hydro power, you just control how much water you let out of the lake to match your load at the time.
Stopped reading after ” ….. the team used models to quantify the amount of power that could be generated”. May as well say “I made a bunch of stuff up to fit my version of reality”. Most computer models simply reflect the biases of their creators and are about as realistic as the imaginary worlds of Half Life, Doom and Quake.
According to legend/folklore, there is a big hole in the ground, somewhere around Spokane Washington; out in the boonies. It’s like a large well, and it is deep. The locasl who know of it, toss all their junk down there; dead cows, refrigerators, whatever. Supposedly, you never hear a sound of anything hitting the bottom, it’s way to deep. Mel’s hole, it is called.
And this Mel chap who used to own it, tried to measure the depth, by dropping a fishing line down there with a weight on it, to see when it hit the bottom. He used 20# test mono nylon, and a one pound lead weight. He set up a plank across the well and a pulley so he could let the line go down the hole. He bought the line in 2 pound spools, and tied them onto the existing line, and then payed that out. Accordfing to Mel reporting this story, he had put at least 20 spools of line down that hole and he still hadn’t reached the bottom; the line just kept on going out and down the hole and the lead weight never did hit the bottom.
Do you know, that neither the talk show host nor the onsite reporter telling of this, or Mel himself, not to mention even one of the callers to the radio station, ever cottoned on to the fact that with over 40 pounds of line sent down that hole, the string would have broken long ago. Clearly the lead was down the hole on something, and the sheer weight of the long string was more than enough to keep the string taught, and continuing to go down the hole.
Mel eventually sold the hole to some investors apparently, and moved to Australia. He hasn’t been heard from since; and apparently they still toss the dead cows down there, and sometimes an old jalopy. The locals don’t let on where the whole is in case the place got vandalized.
LOOK ! ! ! Up in the sky ! ! ! It’s a bird ! ! ! It’s a plane ! ! !
NO ! ! ! IT’S FREE GREEN PIE IN THE SKY ! ! !
[another Marvel moment….and Makani is heavily funded by DOE & NSA front groups]
Fair amount of comments. First of all, I don’t think either kites or sky wind turbines are unfeasable. They simply will have a huge impact on local weather and regional climate. If you put up a system that captures wind over thousands of square kilometers of vertical airspace, you will have unintended consequenses.
Rob L.
“In article they state worldwide wind power 1800TW, extracting a few TW is not going to be a problem for climate, and at 10km altitude won’t even notice it at ground level – whereas thermal power stations do produce noticeable local effects.”
I think you have it backwards there. The jet stream is critical to all weather. Were it is at any moment, the weather on either side of it can be dramatically different. High pressure and low pressure systems are guided by it.
Were I live, it makes the difference between sunshine and rain. You slow it down, what happens? no one knows. The impact would be far beyond the extracted energy. It would be caused by the slowing down of the wind and built up of moisture. Think what happens infront of mountain ranges, rain falls. A large number of these would have a huge impact. As I said in my simple equation, 2800 Square Kilometers blocked and the wind cut in half. That is massive.
Falstaff says
“During any given daylight hour in the US there are some three thousand large body jet aircraft 3-5 miles up. Has this altered the weather?”
Well maybe their exhausts. Otherwise not much, they occupy any spot only for a fraction of a second. They go in every which direction, back and forth between airports. They are not stationary. However, they leave a trail behind when going through clouds, that is quite obvious.
Kites, or airborn turbines, are stationary, they take energy out of the wind, slowing it down over the same area, year after year, decade after decade. Just like a tall building or a mountain.
tty
“Umm … At 30,000 feet and -40 centigrade the density of air is about 0,45 kgm-3. To produce 10 kW per square meter would require a wind strength of about 210 m/s or about 450 mph”
I am only quoting the article I referenced. However if there is less energy up there, then wind wall would be even bigger. Ouch!
Interesting to note that “flying a kite” is a political phrase use to describe releasing a policy suggestion to see if the public are stupid enough to swallow it.
Hey!….. I’ve got this radical idea for power generation.
….. We take this black stuff, coal I think it’s called, and….. wait for it…..wait for it, this is the really radical part……. We burn it to produce heat, to boil water, to create steam, to spin a turbine so as to generate electricity!!!!!
….. BOOOYAHHHH!!!! Who’s ya daddy…. How’s them little orginal apples, ‘eh…?. And apparently coal costs peanuts!
Man. What’s not to like about this???
30,000 ft, how high is Mt Everest? there are calm days on Mt Everest, what happens to kites on a calm day?
And won’t it be fun when the cable breaks near ground level and we have a high voltage line dragging across a city.
I’d seen something simiular some years ago, perhaps in New Scientist (can’t find the ref right now). It doesn’t seem nutty to me, this is where a good proportion of the energy from the Sun could be harvested. Technical and technological problems? Of course there are. But, to the various knee-jerk nay sayers in this thread: what, nuclear, for example? ‘Watch-making by the ton?’ What if there’s a loss-of-coolant accident? What if the sodium coolant of breeder reactors is released? What if someone seriously unwise gets hold of fissile material? I don’t think the consequences of a failure in a well-designed, in engineering terms, system of high-atmosphere wind energy would be so disastrous as an equivalent failure in nuclear. All technologies, of whatever type, involve risks as well as benefits.
As usual, the issue of whether there’s enough wind energy is irrelevant – there’s enough of all kinds of energy (wave, solar, hydro, etc) to meet all our needs. The issue is costs, and I mean total costs, not the fraudulent cost analyses that have been provided by energy source advocates. The wind is variable and therefore not reliable, regardless of where the wind is found.
Unreliable power sources means a need to duplicate capacities to back up wind power, which means duplicating costs. Thus wind energy is junk energy, and pollutes the grid. End of story.