The potential for hydro-electricity is mostly exploited, and it does not offer a solution for the long-term storage of electricity for large parts of the world.

The potential for hydro-electricity is mostly exploited, and it does not offer a solution for the long-term storage of electricity for large parts of the world. Not all countries are like Norway (or Brazil or Canada). There is still space left, but it‘s simply not enough. Instead, many systems with two reservoirs are now being equipped with pumps, again this is ok for short-term storage from hours to days, but no solution to store the Northern sun for the winter. Better produce hydrogen with cheap solar in the sun belt and ship it elsewhere, or move heavy industry to places where green energy is abundant (Iceland, Qatar, …?).