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# Stratospheric Solar Power Collector

 (+7) [vote for, against]

It has been proved that supersonic zeppelins are possible. I'll have to find a link sometime. For now, just trust me on this, please.

:)

Actually, whether or not we really need supersonic zeppelins depends on the latitude at which this Idea is implemented.

Consider the rotation of the Earth. Since Equator is about 25,000 miles in circumference, and the world rotates once in 24 hours, we can figure that if you were on the Equator, you'd be moving around the center of the Earth at about 1042 miles per hour (1667km/hr).

Now suppose you got onto a jet at the Equator, at noon, and (after zero departure delay) flew westward at 1042mph (ground speed, not air speed, and supersonic, of course) for a while, and then landed. The local time would still be noon, because your westward motion would have exactly balanced the Earth's eastward rotation.

If you had enough fuel, you could fly for many hours westward at that speed, and it would still be noon when you landed.

Now suppose you were at the Arctic Circle instead of at the Equator. We can compute the cicumference of that circle easily enough; it is proportionate to the Equatorial circle in the same way that the radius of the Arctic circle is proportionate to the radius of the Equator; it is the "sine" of 23.5 degrees (0.3987) multiplied by that 25,000 miles, or 9969 miles (15950km). At the Arctic Circle the Earth's surface only moves 9969 miles in 24 hours, or 415mph (665km/hr). This is not a supersonic speed!

A westward-flying jet at the Arctic Circle could easily fly that fast. So could zeppelins, of course, if they were designed to also fly at supersonic speed.

We want to take our fleet of zeppelins and fly them so that the Sun is always in the sky, relative to them. We might even want to fly them very near the North or South Pole, just so they can dawdle along, not using much fuel or other energy, to keep flying at the correct speed for that latitude.

The zeppelins are built to be quite large, so that they can rise to the stratosphere and maintain their altitude nearly indefinitely. They can be unmanned, and we might even get away with using hydrogen as their lifting gas.

And of course the main reason for doing this at stratospheric altitude is because the zeppelins will almost always be above all the clouds. Thus do we bypass two of the biggest problems (night and clouds) associated with collecting solar power, without actually going into outer space.

Each zeppelin has a transparent outer bag. Inside the main body of every zeppelin (except one) is a long curved mirror, thin and lightweight and supported by the structural members of the zeppelin.

The fleet of zeppelins fly together in a formation that can be described as a series of nested rings. Stratospheric winds may or may not be a significant factor; there are "streams" which can probably be avoided, and possibly the stratosphere above the North and South Poles are almost always fairly still air (no Coriolois forces causing winds there). It should be possible for computers to automatically maintain the desired formation, with reasonable precision.

Every zeppelin in the rings of the fleet reflects sunlight onto the Main Central Zeppelin, which holds the solar power plant instead of a mirror. To anyone who thinks that it is not such a good idea to do solar power collection near the Pole, because the Sun's rays are diffused by extra atmosphere (Sun typically appears at the horizon), well, this is compensated-for by going to stratopheric altitude. The thinner air allows plenty of solar power to be collected.

To transfer the power to the ground, let's use superconducting rings. A fully-charged ring can be ready to go; another can be getting charged, and a ferry can be carrying a discharged one up to swap with the charged one.

 — Vernon, Dec 26 2006

"The Supersonic Zeppelin" http://www.tangento...ew&id=89&Itemid=259
There is a little (not much) about the notion here. [Vernon, Dec 26 2006]

Superconducting ring http://www.imagesco...y-storage-ring.html
On a large scale, useful for storing a lot of energy. [Vernon, Dec 27 2006]

IKECE IKECE
As mentioned in an annotation. [Vernon, Jan 02 2007]

OK, I added a link. That idea has been around for a while.
 — Vernon, Dec 27 2006

True, but the solution is simple; just fly the fleet down to the other Pole for the next six months.
 — Vernon, Dec 27 2006

Better to tether the Zep to the ground with a long cable. Somewhere inside the Arctic circle with access to the grid (Scandinavia, Russia).
 — BunsenHoneydew, Dec 30 2006

 Ummm, you say supersonic zeppelins are possible?

 //While Zeppelins have long been a favorite of the alternate history set, "The Supersonic Zeppelin," by Ben Bova, is straight science fiction.// This is from your link...

I like the idea in principle, I just think it will be cheaper and easier to use a "stationary" orbital power plant that keeps itself in the sun.
 — emjay, Dec 30 2006

 Bova's story was based on fact, and the link said that, too. (That's why they call the genre SCIENCE fiction.) The story itself referred to the facts; I have to dig it up sometime so I can post a more informative link.

 I agree that orbital solar power plants have benefits over this Idea, but this has its own benefits, too.

 First, note that orbital stuff may be stationary relative to the surface of the Earth, but they are not stationary otherwise. So, all those hundreds/thousands/more tons of solar power plant have to be lofted high against gravity and accelerated to many thousands of kilometers per hour. Here the lofting can be done with lifting-gas, and the speed can be quite low (approximately zero AT either Pole).

 I basically only mentioned the supersonic bit to show that the Idea is POSSIBLE anywhere else on Earth, but I do agree that the faster, the more impractical (takes energy to overcome air resistance, so only the difference between what is collected and what is used can actually be sent to the ground). In Space, of course, once the desired speed is reached, you just coast along without needing to use much more.

 Next, in Space a power plant has a waste-heat problem (see the IKECE idea for a more thorough description of that); on Earth waste heat from this power plant can be dumped into the very cold stratosphere, mostly via convection.

 Next, the Earth's atmosphere offers some protection for this Idea from micrometeoroid damage, while a space-based power plant doesn't benefit from the atmosphere (would burn up!).

Finally, in sending power to the ground, a space-based system must convert the energy into a power beam (microwaves, likely), and that beam must then be converted to electricity, with efficiency losses in both places. Here, either with superconducting rings or with a direct-power-line/"tether", those energy losses don't exist (well, the cost of ferrying rings could count as a "loss", so the power-line/tether could indeed be better).
 — Vernon, Jan 02 2007

 YES! I just knew it would say "Vernon" when I finished reading it!

+ from me.
 — Zimmy, Aug 29 2010

 I'm confident that you'd use much more than 50% of the power collected, just keeping these things moving at the velocities mentioned. In fact, drag for something inherently large (like a zepplin) - would probably account for >>100% of the power available from solar collection.

 Long story short - Why not just go tethered and live with the 50-50 day/night problem?

 Furthermore, if you looked at construction costs, hydrogen initial generation cost as well as replenishment (most hydrogen storage leaks) - I'm thinking the payoff of being above the clouds would be negative as well.

To my mind, if solar collection is ever going to work as a viable alternative, it's going to be because of cost efficient large scale ground coverage, in arid, mostly full sun areas.
 — Custardguts, Aug 29 2010

[custardguts], please keep in mind that at this site some Ideas are more deliberately half-baked than others....
 — Vernon, Aug 29 2010

 So the custard-filled torque converters in the driveline and the rocket launched Stratoshperic electrical discharge probes were just implied then?

Not to mention the joll-roger tailplane markings and the Robo-parrot autopilot?
 — Custardguts, Aug 29 2010

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