Solar balloons?

[neilsox]

Space solar power looks puny for the next ten years, but you should never say never. We can do it now, very small scale for about a million times what it costs to make electricity from coal. The main problem is launching mass into space is very costly. Details at http://www.spacesolarpower.wordpress.com Cost will come down if we start doing space solar power, but not enough to make it cost effective, near term.
How about we use big hydrogen balloons, free flying at an altitude of about 30 kilometers and lasers to send the energy to existing solar energy sites? Low cost at the receiving end. The lasers are expensive, but not nearly as costly as getting mass to LEO orbit or GEO orbit. The lasers can illuminate spots as small as one square meter from a distance of 100 kilometers. Minimum spot size is about one kilometer for radio beams, with a reasonable size transmitting antenna. A square kilometer is about optimum for a gigawatt, but about a square meter is optimum for a kilowatt. In the Northern hemisphere the balloons launched just North of the Equator could be recovered near the Arctic circle, a few months later. Hydrogen is non-flammable above about 10 kilometer altitude because the air is too thin to support combustion. The world helium supplies are inadequate for large scale balloon use. Neil

 

[kelvinzero]

It could certainly be a benifit if you could get above the clouds giving reliable power.

Lasers are pretty inefficient. What about a cable? It could be studded with smaller balloons to counter the cable's own weight.

You might not need hydrogen for lift. Solar balloons are hot air balloons powered by solar energy. I dont know if they can stay up at night though

Another idea I had was high altitude balloons that produce hydrogen from solar power and water. The hydrogen would be ferried down occasionally and water either ferried up or perhaps collected from condensation. These things would never land.

However I expect we have not really begun to exploit solar power on earth yet (disregarding that most forms of energy on earth including anything we burn in oxygen are ultimately from solar energy)

 

[Mee_n_Mac]

Space solar power looks puny for the next ten years, but you should never say never. We can do it now, very small scale for about a million times what it costs to make electricity from coal. The main problem is launching mass into space is very costly. Details at http://www.spacesolarpower.wordpress.com Cost will come down if we start doing space solar power, but not enough to make it cost effective, near term.
How about we use big hydrogen balloons, free flying at an altitude of about 30 kilometers and lasers to send the energy to existing solar energy sites? Low cost at the receiving end. The lasers are expensive, but not nearly as costly as getting mass to LEO orbit or GEO orbit. The lasers can illuminate spots as small as one square meter from a distance of 100 kilometers. Minimum spot size is about one kilometer for radio beams, with a reasonable size transmitting antenna. A square kilometer is about optimum for a gigawatt, but about a square meter is optimum for a kilowatt. In the Northern hemisphere the balloons launched just North of the Equator could be recovered near the Arctic circle, a few months later. Hydrogen is non-flammable above about 10 kilometer altitude because the air is too thin to support combustion. The world helium supplies are inadequate for large scale balloon use. Neil

So how many free floating balloons would it take to replace a typical power plant ? And as they float away are you planning to beam their collected energy to the same receiver or to different receivers spread under their wide flight paths ? How will airplanes (for one) know where the keepout corridors are as they move about ? I think the tethered windmills make more sense.

http://www.skywindpower.com/ww/index.htm

 

[neilsox]

It may take a million balloons to replace one large coal fired electric plant and that will be a hazard to other aviation. Air traffic control would need to keep track of where the balloons are and advise other craft to change course so as to miss the balloons by a safe margin.
In theory, the balloons can have dimensions as large as a mile allowing then to collect up to a gigawatt, each. Neil

 

[Boris_Badenov]

Actually this isn't a bad idea for JP Aerospace to pursue.
http://www.jpaerospace.com/
This might very well be within their capabilities.

 

[Mee_n_Mac]

It may take a million balloons to replace one large coal fired electric plant and that will be a hazard to other aviation. Air traffic control would need to keep track of where the balloons are and advise other craft to change course so as to miss the balloons by a safe margin.
In theory, the balloons can have dimensions as large as a mile allowing then to collect up to a gigawatt, each. Neil

OK say we have mile long "balloons" collecting a GW (peak) each. (I haven't done the math to see if that's reasonable but I'll guess we're off by more than an order of magnitude). Lets assume such craft could withstand the winds aloft. Why not go the extra step of mounting some electric motors (now we have dirigibles) to keep them semi-stationary over their rectenna farms ? Thus we have fixed and relatively few collection and power distribution points.

 

[tampaDreamer]

The elephant in the room with all space or airborne solar power solutions is how much more powerful is the sunlight at that altitude, and is there any kind of a diminishing returns effect with harnessing it?

 

[neilsox]

Yes giant hot air balloons can fly almost as high. and only descend about one mile over night. I'll guess diminishing returns limit size to about one cubic mile per balloon. Class suits from lawyers may be the worst problem. Wind gusts and wind sheer are rare above about 20,000 feet, so the balloon does not have to be very sturdy. If launched from the surface as one assembly, wind gusts and sheer are a bad problem even before launch day. The balloon is subject to about 99.9% of surface gravity, so it will disintegrate under it's own weight, if much larger than a cubic mile, with present materials. CNT = carbon nano tubes may soon make 5 cubic miles possible, if not cost effective.
On the average about twice as much sunlight falls on a square mile compared to typical surface locations, but half the power may be lost getting the energy to a location on the surface. The main advantage is we avoid the cost of purchasing or leasing the square mile on the surface, and the existing solar sites can produce energy if there is a solar balloon within range, at least one more hour per day. Neil

 

[Mee_n_Mac]

The main advantage is we avoid the cost of purchasing or leasing the square mile on the surface, and the existing solar sites can produce energy if there is a solar balloon within range, at least one more hour per day. Neil

I'm not following you here. While I agree that moving the collector to the sky saves that space on the ground, you'll still need ground space to emplace the rectenna to receive the energy from the balloon. If the balloon is free to move with the upper air currents you'll need a lot of these. I note that I've dismissed the concept of using lasers to beam the energy down. My estimate is that high power semiconductor diodes are still too inefficient to be used for this purpose and the problems of scattering and atmospheric absorbtion further compound the situation.

 

[MeteorWayne]

Yes giant hot air balloons can fly almost as high. and only descend about one mile over night. I'll guess diminishing returns limit size to about one cubic mile per balloon. Class suits from lawyers may be the worst problem. Wind gusts and wind sheer are rare above about 20,000 feet, so the balloon does not have to be very sturdy.

It's obvious that you don't look at upper air meteorological charts! Ever hear of the jet stream? Any idea of what heights that occures at?

 

[scottb50]

Yes giant hot air balloons can fly almost as high. and only descend about one mile over night. I'll guess diminishing returns limit size to about one cubic mile per balloon. Class suits from lawyers may be the worst problem. Wind gusts and wind sheer are rare above about 20,000 feet, so the balloon does not have to be very sturdy.

It's obvious that you don't look at upper air meteorological charts! Ever hear of the jet stream? Any idea of what heights that occures at?

I've experiences quite a bit of turbulence up to 45,000 feet crossing a frontal system with Thunderstorms. Usually it was just a few bumps but anything that looked like it could be sustained would require a lower altitude and a deviation at least in the Lears.

Above 60,000 feet I think you would be pretty safe except on rare occasions, especially with a balloon because you are not dealing with aerodynamic forces, stall speed and Mach tuck.