You can say that wind turbine is not 100% efficent, but it still produces energy. So we are talking about open systems, where the climate and atmosphere can produce energy almost infinitely. So over 100% percent means how much more can buouancy add to energy generated by the windmills.
See my post(s) upthread: the buoyancy energy comes from the windmills to begin with.
The smiley is intended to convey the meaning that you know that’s wrong, right?
Just for the mathematically inept who might read the thread: 1000 cubed is 1,000,000,000.
200 million, supposing the initial calculations are correct.
Egads. :eek:
:smack::smack::smack::smack::smack::smack::smack:
How did I miss that? I know that 100 cubed is a million; somehow I had mixed 100 with 1000 in that thought.
No, my smiley was to acknowledge that there is nothing “mere” about 200,000 windmills. I really thought that was the right number.
:smack::smack::smack::smack::smack::smack::smack:
You are correct. 200 million windmills is the right number. Increase the required land area for our wind farm by a factor of 1000; now we’re talking about a patch of land 7500 kilometers on a side - only six times the area of the United States.
See above 
The answer is none. None more energy. Actually less than that.
I don’t think that’s right.
Suppose you didn’t pump the H2 up into the mountains, and instead used Mangetout’s balloon-conveyor-belt rig to extract work from the rising balloons as those balloons buoyed themselves up to mountain elevations. In either case, you burn the stuff in your power plant, condense the flue gas, and end up with high-altitude liquid water, ready to send downhill to your hydroelectric facility.
So the gravitational potential energy in that high-altitude liquid water wouldn’t coming from the pumps you used to drive the H[sub]2[/sub] up into the mountains, and it wouldn’t come from H[sub]2[/sub] buoyancy effects.
So, you are saying that if you have a pipe full of H2 and a valve on top of it. When you open the valve - nothing happens.
If the bottom end of the pipe is not open to atmosphere, this is correct.
And if the bottom end of the pipe is open to atmosphere, and the hydrogen rises because of buoyancy, you cannot recover more energy than you put into creating that volume of hydrogen in the first place.
Million litres per day makes me more than happy - so 200 it is!
Understood, but nobody said this has to be a closed system - we can allow the gas to be warmed ambiently.
Thanks for the explanation - this was certainly a gap in my understanding of the system.
I’m under absolutely no illusion about this, but knowing the bald fact that perpetual motion is impossible is not the same as knowing the ***precise and expanded detail ***of why any particular attempt at perpetual motion fails.
Atomic bombs. If somebody is vaporized by a nuclear explosion, they cannot die of hunger or thirst.
If we set water to be boiled by the explosions, we can use the steam to run turbines.
We can also build windmills to take advantage of energy in the concussion wave.
Generating free energy is trivially easy. You don’t have to run a pipe 200 km to the top of the Atlas mountains, or bother producing hydrogen. Simply run a pipe 3 km straight up. The pressure at the bottom is 101.325 kPa. The pressure at the top is around 70 kPa. As the high pressure air at the bottom rushes through the pipe to the partial vacuum at the top, it turns a turbine. You could stack multiple turbines in the pipe, put one every fifty meters or so.
Be careful not to make the pipe too large though, or all of the air down at sea level will end up 3 kilometers up, and we’ll all suffocate.
This is a whoosh, right?
That’s the sound the air makes as it rushes up the pipe, right?
Simplified: A closed, vertical pipe, 1000m high, full of H2 and O2 and some water at the bottom. At the top you oxidize the H2 to H2O, covert all the energy to electricity and send it down to the bottom over loss-less wires. At the bottom the electricity is used to crack an equal amount of H2O. The water produced at the top flowing down to the bottom gives you some extra energy for free.
But as Joe pointed out, the extra energy is needed to expand the gasses at the bottom. The pressure of the gasses on the water increases the energy you will need to crack it. When you oxide at the top, under lesser pressure, you will get back less energy than you spent cracking. The extra energy goes into pushing the gasses up the pipe. The gas atoms increase in potential energy as they are pushed up; they lose the potential energy as they flow back down as water.
You don’t need to know details, you just need to believe in thermodynamics. The most energy you can get out of the system is what comes out of the wind turbine’s generator. Electrolysis - net energy loss. H2 rising - net energy loss. Recovery of H2 rising energy - net energy loss. Capturing heat from burning H2 - net energy loss. Turning heat back into electricity - net energy loss. Turning water flowing down hill into electricty - net energy loss. I would be really surprised if for every 100 watts coming from the wind turbine generator you ended up with over 20 watts at the end of this Rube Goldberg plan.
katunari - what is the water pressure at the bottom of a 4000 meter high column of water? What happens if you run a pipe from there to a tank of H2 at atmospheric pressure and open the valve? Hint: the H2 isn’t going into the pipe.
So you have to compress the H2 to greater than the water pressure - this takes energy to run a compressor that isn’t 100% efficient. How will you get energy back out of the rising H2? No method will be 100% efficient. You think you can just use more free wind energy to get back the difference, but why throw it away in the first place?
May or may not be true, which is why I’m trying to understand the details. I’m still pondering where the gravitational potential energy comes from that we extract from the liquid water flowing down to the Sahara. The hydrogen has been brought up to the 4100-meter elevation, but we are taking oxygen that was already at that elevation and combining it with our imported hydrogen to make the liquid water. Solar energy (indirectly) or something else may be involved here. I will put some numbers on all of this tomorrow.
[sub]and I will check my calculations better…[/sub]
I think you misunderstand the premise outlined in the OP. The liquid water, produced at the 4100-meter elevation, is not being sent back down to the windmills on the coast; it’s flowing down the other side of the Atlas mountains, toward that artificial lake in the Sahara. Not using it to aid in transporting H[sub]2[/sub] uphill, just using it to generate hydroelectricity, like the Hoover Dam.
You are burning O2 that is already at the top. Of course you will not end up with a hypoxic bubble. That O2 will be replaced by convection. Likewise, you will not end up with an O2 bubble at the electrolyzer. So effectively, the energy comes from convection which as you surmised, is ultimately powered by the sun.