There was a plan, to use giant cylinders of landscape as hydraulic batteries. The problem was the cost of excavation or building the cylinder. Then this came a

There was a plan, to use giant cylinders of landscape as hydraulic batteries. The problem was the cost of excavation or building the cylinder. Then this came along, not even promoted as the future.. https://www.newcivilengineer.com/the-future-of/future-of-tunnelling-how-bots-will-build-tunnels-of-the-future-01-10-2021/ https://www.newcivilengineer.com/the-future-of/future-of-tun... And it's ideal.as in they could turn testsites into batteries. You could have such a battery in an any abandoned quary today. Chip the walls smoth, freeze an ice plug, pump water beneath and use the stored pressure.