This exists, and is called "pumped hydro" energy storage. But it needs favorable geography and/or huge use of space. There isn't a single technology for all o

This exists, and is called "pumped hydro" energy storage. But it needs favorable geography and/or huge use of space. There isn't a single technology for all our energy storage needs, pumped hydro, batteries and lots of others all have their niche and efficient use cases.