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Tapping the Sky
August 19, 2005 8:19 AM   Subscribe

45,000 pounds + four 130 foot rotors + up to 200 mph Jet Stream winds = Energy Problem Solved
Like the monster mother of all kites, a company called Sky Windpower (which sports an excellent website about high altitude wind power) has been founded by an Australian engineer with three others to attempt to harness the near limitless windpower of the jet stream with a machine they call an FEG (Flying Electric Generator).
They're currently seeking $4 million to build a 200 kilowatt prototype but still need to get FAA clearance to fly it. The production models would generate 20 megawatts each and would be flown in farms of up to 600 turbines to generate enough power to light up two cities the size of Chicago. Power and control of the huge machines would be handled by a three inch thick tether connected to a winch on a ground station.
Man, I love Popular Science!
posted by fenriq (35 comments total)

 
I wonder about all these natural energy ideas. Won't things like this, and the deep sea cold water idea, affect the environment? Maybe not enough to matter?
posted by tomplus2 at 8:43 AM on August 19, 2005


How much is that cable going to weigh? A cylender three inches thick, at a 45 degree angle, reaching 35,000 feet would be 2,429.4 cubic feet, or 68792.9471. That's 111 tons of kevlar, 341 tons of titanium, and about 100.8 tons of carbon nanotube rope.
posted by delmoi at 8:55 AM on August 19, 2005


sorry, 68792.9471 liters.
posted by delmoi at 8:56 AM on August 19, 2005


I think this idea has been around for a while, which presumably means they have been looking for money for a while. I have a number of concerns.

The biggest wind turbine in production at the moment is 3.6MW. A 5MW turbine is in testing in Germany and their seems to be some expectation within the sector that there is not much room to continue the expansion in capacity that has occurred over the last 15 years. Making the jump to an operational turbine of 20MW is not a simple task. The history of the wind turbine demonstrates that smaller incremental jumps in capacity tend to be successful while attempts to make large-scale jumps end in failure. Further, the turbines in operation today have speeds at which they cut in and speeds at which they stall. They stall in order to prevent them from 'running away' and destroying themselves. Thus there are currently no wind turbines capable of operation at the 200mph described in the article. Given that there is no market for such turbines on the ground, pushing up the capabilities of the turbines to meet the criteria described will require a major investment solely for the purposes of this project. For reasons delmoi highlights the technology would also need to be as lightweight as possible, adding a further difficult dimension to the design criteria.

I wonder about all these natural energy ideas. Won't things like this, and the deep sea cold water idea, affect the environment? Maybe not enough to matter?

To an extent they will but in many (most) cases the effects will be generally insignificant. Even a large land-based windfarm will have negligible impact on wind flow characteristics well within a kilometer of the farm.
Environmental impact assessments are often required for large (and even quite small) renewable developments in Europe, so there is quite a lot of data as to impacts. Offshore wind farms in the UK will be subject to a number of environmental impact studies to determine the range and scope of their impacts, including with regard to their effects on bird migration and feeding grounds, silting, sealife, etc.
A colleague of mine is currently working on a project to assess the effects of wave energy machines. The early results suggest these are relatively minor.
Bigger site specific projects have the potential to cause local ecological impacts. Tidal barrages for example are quite major projects and can have significant ecological impacts at a local level. They are rare so far though, and their high capital costs means future development looks limited. Good practice requires impacts are assessed before construction and accounted for in the planning process.
posted by biffa at 9:21 AM on August 19, 2005


From their website "But, while it is not well known, balloons tethered at up to 15,000 feet already exist along the southern border of the United States carrying radar equipment to detect drug flights."

So looks like current tech can keep these things at 15k ft which is plenty windy enough.
posted by zeoslap at 9:21 AM on August 19, 2005


TANSTAAFL
posted by freebird at 9:21 AM on August 19, 2005


Not a free launch, freebird, but the sun picks up the check.
posted by weapons-grade pandemonium at 9:29 AM on August 19, 2005


Similar crazy innovative wind energy project: the ladder mill.
posted by swordfishtrombones at 9:33 AM on August 19, 2005


According to the site, the jetstream ranges from a low of about 15000 feet to a high of about 25000 feet so the weight of the tether would be a bit lower but I do see that that's a pretty large issue to surmount. Alot of lift can be generated with sustained winds at 200 mph though.

tomplus2, I'd be more concerned about the deep sea cold water concept than harnessing some of the jetstream though both would have some impact on the environment.

And no, it won't be easy but a working prototype would go a long way toward demonstrating the concept's feasibility.

I also have to think about jets accidentally straying into a windfarm at 20,000 feet and shudder at the potential for tragedy even though I know it would be pretty straightforward to mark the area and detour planes around it.
posted by fenriq at 9:44 AM on August 19, 2005


I'm not surprised they're still looking for money; if I had a spare 4 million to spend on wind energy, I'd probably sink it into a conventional 2-3 MW turbine project rather than a 200 kW prototype...
posted by nickmark at 9:45 AM on August 19, 2005


I don't think they'd need to go as high. Some windfarms on the plains have been experiencing the "night jet"; near-jetstream winds coming close enough to ground.

I have a bad feeling about schemes like this. Maybe I'm too used to anchoring my turbines in hundreds of tonnes of concrete, like we're doing at Erie Shores right now. How do these FEGs make a soft landing for maintenance?

biffa, you were pretty much spot on with the wake effects of turbines. You'd want to keep downwind rows of turbines about 8 diameters apart so that they have manageable wake losses. I doubt you could measure the effects on flora and fauna.
posted by scruss at 10:18 AM on August 19, 2005


Wait till the first commercial airliner hits one.

This seems much more like an idea from a futurist than it does from someone that is trying to solve energy problems.
posted by 517 at 10:20 AM on August 19, 2005


I had read about this somewhere before and thought it looked cool.

Wait till the first commercial airliner hits one.

As the website points out, there are already high altitude things tethered around the US (and I'm sure elsewhere.) Commercial flight paths are very well-worn, jets don't just fly whereever they think it might be cool to go. I'm sure it would be easy to anchor them and flag them in areas that don't get commercial air traffic.
posted by OmieWise at 10:27 AM on August 19, 2005


scruss, the platform can be flown almost like a helicopter so it really shouldn't pose too much of a problem to bring them down as needed. Except for that last few hundred feet where the wind's not very strong!
posted by fenriq at 10:48 AM on August 19, 2005


Not a free [lunch], freebird, but the sun picks up the check.

I couldn't prove it, but I believe wind is caused by the rotation of the Earth, not the Sun. So therefore this will actually cause the Earth's rotation to slow. Fun!

(Much like my other favorite "free" energy solution: putting a giant a giant toroidal solenoid around the Earth's orbit. )
posted by jlub at 10:51 AM on August 19, 2005


Further, the turbines in operation today have speeds at which they cut in and speeds at which they stall. They stall in order to prevent them from 'running away' and destroying themselves. Thus there are currently no wind turbines capable of operation at the 200mph described in the article.

If the wind speeds is the same at all times (as it is in the jet stream) you could just easily design a turbine with blades set at an angle that would work best at those wind speeds. The reason earth-bound wind turbines are failing in high winds is that they are designed for average wind speeds, and not for storms.
posted by kika at 11:32 AM on August 19, 2005


I believe wind is caused by the rotation of the Earth, not the Sun. So therefore this will actually cause the Earth's rotation to slow.

I'm trying to figure out exactly which logical fallacy this exemplifies.
posted by goethean at 11:38 AM on August 19, 2005


I'm trying to figure out exactly which logical fallacy this exemplifies.

Careful, you could hurt yourself, it's a doozy.
posted by OmieWise at 11:47 AM on August 19, 2005


jlub: I believe you'd be incorrect. Think of it this way: if the wind were caused by the rotation of the Earth, then a) why does wind velocity vary? and b) why does wind direction vary? Rotation of the earth has an effect on the overall direction of wind patterns, but the motive energy comes from solar heat (which varies by the hour, by time of year, and by surface characteristics), not the Earth's rotation.

Also, the sun doesn't really "pick up the check"; the sun won't output more radiation to conveniently make up for the subtractions of windfarms. The main reason why it won't screw up the jet stream, and by extension, our climate is that there's much more energy in the jet stream than we could possibly use. That usage, therefore, won't make more than a tiny, insignificant dent in the passage of the jet stream. That's the theory, anyway.

Fun fact: Every space launch, because they are launched into the east to take advantage of the momentum of the Earth's rotation, slows down the Earth's rotation by a tiny, tiny fraction. I don't know if it's enough for even atomic clocks or astronomers to notice.
posted by skoosh at 11:56 AM on August 19, 2005


I realize we're derailing a bit here and apologize, but isn't the earth's rotation slowing anyhow? Something to do with the drag induced by tides and/or the moon's orbit?
posted by alumshubby at 12:06 PM on August 19, 2005


I'm trying to figure out exactly which logical fallacy this exemplifies.

Well, the biggest problem is that it violates conservation of angular momentum. You can't change the angular momentum of the Earth unless you have somewhere else to put it. In the case of skoosh's space shuttle example, the earth loses a tiny bit of angular momentum to the shuttle, but that angular momentum is transferred back to the Earth when the shuttle lands (or really, as it descends through the atmosphere).

The moon is stealing the Earth's angular momentum through tidal interactions. The Earth's rotation slows, and the moon gets pushed into a higher orbit.
posted by yarmond at 12:14 PM on August 19, 2005


isn't the earth's rotation slowing anyhow? Something to do with the drag induced by tides and/or the moon's orbit?

Tidal acceleration. On the other hand, there's also a countervailing effect apparently caused by the rebound of the northern continents from the weight of the icecaps of the last ice age: see ΔT (the difference between Universal Time and Terrestrial Time) for details. I love (non-hostile) derails.
posted by skoosh at 12:22 PM on August 19, 2005


Well if the shuttle launches to the east, they should land to the east to give the earth all it's energy back.
posted by parallax7d at 12:23 PM on August 19, 2005


Beaten to the punch by yarmond. In my defense, I was thinking of all space launches, not just shuttle launches, including the planetary probes that (I'm pretty sure) are never coming back to return their angular momentum back to Earth. Let it be noted here that IANA physicist.

On preview: someone else has been seduced by the allures of Live Preview, I see. ;-)
posted by skoosh at 12:28 PM on August 19, 2005


4 rotors @ 130 feet each
x (times) 600 turbines in a farm
==================
(equals) one giant blender.

I hear condor smoothies are delicious.
posted by surplus at 12:42 PM on August 19, 2005


This seemed exciting until I realized that it was from Popular Science, and thus is doomed by the Popular Science curse. (Which says, of course, that absolutely nothing of interest that Popular Science predicts ever comes to pass.)
posted by Western Infidels at 12:51 PM on August 19, 2005


...there's much more energy in the jet stream than we could possibly use.

And 640KB should be enough for anybody, too.

I doubt the human race will ever have the good fortune to be burdened with more energy than we know what to do with. If it were to become very cheap, we'd find interesting new ways to use it all up.
posted by Western Infidels at 12:54 PM on August 19, 2005


Commercial flight paths are very well-worn, jets don't just fly whereever they think it might be cool to go.

Before GPS, that was true. Now, long distance flights seldom stick to airways. Reserved airspace, however, is routine and generally problem-free.
posted by dreamsign at 1:29 PM on August 19, 2005


I'm trying to figure out exactly which logical fallacy this exemplifies.

Well, the biggest problem is that it violates conservation of angular momentum.


I was being tongue-in-cheek, but this is nonsense. If you spin a top, where did the angular momentum come from? When the top stops, where does it go? The point being that angular momentum is only conserved in a closed, non-inertial system on which no torque is applied.

Not disputing skoosh, though, I think everything he wrote was correct.
posted by jlub at 2:07 PM on August 19, 2005


man, I want to add large promenade decks and get a Gulf princelet to build lawn tennis courts, spacious interior recreation facilities, and a five-star white linen tablecloth restaurant atop this device.
posted by mwhybark at 6:19 PM on August 19, 2005


skoosh,
Don't forget the space launches from the Western Space and Missile Center, Vandenberg AFB. Check the VAFB web site for upcoming unclassified launches. Lots of payloads launched into North/South orbits over the last few years too.
posted by X4ster at 10:59 PM on August 19, 2005


Even if these FEGs weren't marked on aircraft navigational charts (and they would be!), don't airliners have radar these days? A bunch of giant turbines and steel cable hanging in the sky ought to be at least slightly radar-reflective. Especially if they put those radar-reflector balls on 'em.

Re "more energy than we could possibly use", that phrase makes me awfully nervous too. The seas were vaster than we could possibly affect, but we've managed to reduce most fishing grounds to scarcity or near-extinction. The plains and prairies were limitless, but they're full now. The woods were deep and ancient and powerful, but they're gone now. Human demands will grow exponentially, and as they say, that's faster than any polynomial.

But this isn't a reason not to use wind power at all. Just a reason not to believe we can't run out of it.
posted by hattifattener at 12:19 AM on August 20, 2005


surplus, the average cat sees off more birds in a year than a wind turbine. We've learnt from California errors.
posted by scruss at 8:50 AM on August 20, 2005


surplus:

Also, I'm not aware of too many condors cruising around above 15,000 feet. Just ain't much to eat up there, you know.

Now one very large, transient, kite-eating bird might evolve to fill that niche... (sorry to the JIR)
posted by trigonometry at 12:34 PM on August 20, 2005


X4ster: Oh yeah, I forgot about the polar orbits. Oops. I have, however, discovered this nifty feature, so at least I could find out someone had replied.
posted by skoosh at 10:45 PM on August 25, 2005 [1 favorite]


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