Germans are developing the idea to use huge reservoirs in the sea (at the bottom) to pump out water to have internal space with high pressure and then let water in by moving electric generators.
Find details here
What is good about the idea that comparing to accumulator batteries these bottom water storages can have much longer life and these don't lose their capacity after a while as batteries do.
That's a brilliant idea but as I understood they pump water out with ...electricity... (!) O
Of course, it can be reasonable when there is an overproduction of electricity so you just convert it into the potential energy and then get it back when you need.
But I am thinking how about to convert mechanical energy into potential energy directly?
What if wind turbines will move not an electric generator but just a simple mechanical pump and then when you need you convert it from these reservoirs to electricity?
What do you think, seasteads?