I was thinking about Hydrogen balloons and that large ones which are used for weather balloons which sometimes go up to 100,000 ft (approx 30km). Then I was wondering, how much potential energy has the balloon gained with the balloon and the weight it carries to get up to 100,000 ft. It seems the object would have a lot of potential energy at that height. If the object was rolled down a ramp from that height, it would generate a lot of energy going down a 30km height ramp. Then how much energy was used to get it to lift, to produce the hydrogen in the first place?
So my question is, could there be any situation where the potential energy the balloon and its cargo gained exceed the energy it took to make the hydrogen in the first place? Then, if so, how could a cycle be set up where the lifting energy of the hydrogen is used to liberate more hydrogen and produce energy.
Here is another idea, what if the balloon started at the bottom of the ocean, a Electrolysis device is separating hydrogen and oxygen from the water down there. A balloon collects the hydrogen and oxygen and pulls upwards. The balloon is attached to a string which it pulls up and turns a pully (wheel) at the bottom as it goes up. Could the rotation of the wheel gain more energy than the cost to extract the hydrogen. I guess the weight of the string would be a factor to consider as well.
My thought is that all of this is very unlikely, as it seems like a perpetual motion device, as the hydrogen and oxygen could be re-combined and it would fall back downwards as water and the cycle would be repeated. The question would be, where does the energy come from? it has to come from somewhere, so this seems very unlikely. I cannot think of where the energy comes from.
But can anyone work out the calculations even for a very basic calculation?