And if you don’t know for sure you can always default to a “Saarlands”

Would ask for the details about that water( quality , application and so on). Than I will offer them a cheaper source located near the destination. Doing such logistics would be absulutely stupid (Except for water of ultra high purity or large Deuterium/Tritium contents)

Fill it by a 12000km long 2cm wide tube. Do not underestimate the pressure needed to get a reasonable flow. Ever tried soak up honey with a straw?

Sounds plausible. In order to store more energy you’d need a longer wire. To compactify your setup you can wind the wire to a spiral and get a spring ( maths changing a bit due to Shear Modulus however). This way you can store more energy in the etall wire