
Energy Storage Using a Rock-Filled Train on a Hill (2016) - mhb
https://www.wired.com/2016/05/forget-elons-batteries-fix-grid-rock-filled-train-hill/
======
olejorgenb
Discussion on similar ideas including this:
[https://news.ycombinator.com/item?id=17789456](https://news.ycombinator.com/item?id=17789456)

