camelot-forum.co.uk

Remember this getting discussed in "That other place" a few years ago - the idea of pumped hydro using a fluid that is more dense than water in order to get more power and energy out of a similarly sized water-based system.

Looks like a pilot plant is going to be built in an old mine in Devon.

https://www.imeche.org/news/news-articl ... r-in-devon