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?
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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.