"RheEnergise said it invented the new high-density fluid, known as R-19. Chief executive Stephen Crosher told Professional Engineering that the liquid is a fine-milled suspended solid in water, with low viscosity and low abrasion characteristics. The base material is used in oral medication applications, in a similar way that chalk is used as a bulking agent for pills and tablets. He said the raw materials are common and available, including in the UK, and the fluid could either be manufactured on-site or at a depot. "
Hydro is very geographically restricted, halving the height makes it less so.
I like the idea of using old coal mines, there’s been pilot projects in Germany and Australia but I’ve never seen them amount to anything
https://www.imeche.org/news/news-article/high-density-pumped-hydro-could-be-installed-on-thousands-of-small-hills
"RheEnergise said it invented the new high-density fluid, known as R-19. Chief executive Stephen Crosher told Professional Engineering that the liquid is a fine-milled suspended solid in water, with low viscosity and low abrasion characteristics. The base material is used in oral medication applications, in a similar way that chalk is used as a bulking agent for pills and tablets. He said the raw materials are common and available, including in the UK, and the fluid could either be manufactured on-site or at a depot. "
I like the idea of using old coal mines, there’s been pilot projects in Germany and Australia but I’ve never seen them amount to anything