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.
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.
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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?