Space pump hydroelectric I'm in the need of some help here. I'm an artist and I want to paint digitally something that can have an use for the future of humanity. I would like to create an illustration about a futuristic hydroelectric that uses the vacuum of space to rise sea water into long hoses and then, before the water actually escapes, let the water come back, falling into generators.
So my question is, (I know it's a crazy idea but I'm allowing to dream technology will find the way to support structures with electric rockets), if we were capable to put a hose from the ocean to space, could it pump out water? Is that even possible?
 A: No.
It's a little counter intuitive, but vacuum doesn't suck water up. Instead, air pressure pushed down everywhere.
If you had a vacuum hose from space down to the ocean, air pressure would not push down inside the hose. Since water is being pushed down everywhere else, it would rise in the hose until the weight of the lifted water pushed back hard enough to balance the upward push. This happens when the water has been pushed up 32 feet. See this Veritasium videos - World's Longest Straw
Trees play tricks to get it higher, but not above 300 feet. See these - How Can Trees Be Taller Than 10m? and How Trees Bend the Laws of Physics
A: NO.
Sea water has to climb across the gravitational potential to reach space. Someone has to work against gravity. Don't be under the impression that vacuum would suck up liquid water like a suction pump. Supposing something similar to happen would lead to the creation of a perpetual energy source (wherein vaccum does work for you and you convert that energy to run turbines), which would violate Laws of Thermodynamics.
What will happen here is because the pressure above the water(inside the hose) is zero, now to maintain the vapor pressure above its surface (which is proportional to the temperature of water body) more water gets vaporized and rise up. Since the temperature at high altitude is low, this waster vapor is likely to condense onto themselves and fall back as droplets, unless you have a mechanism that maintains a warm temperature inside. Even if you manage to get this to the other end (vaccum end) you will only have water vapour and not liquid water
A: Water pressure increases about 1.47 PSI per meter of depth due to the weight of the water (pressure may vary slightly with exact water temperature and purity). At a 10 meter depth water pressure is about 14.7 PSI which is about 1 atmospheric pressure. A complete vacuum in a pipe or tube could not lift water more than about 10 meters above sea level as atmospheric pressure could only push the water up about that high. And, as always, there is no free energy machine as it would violate thermodynamic laws.
