> All of the metal at a scrap yard I know of amounts to less than half that weight, for reference. That's not a great reference point when you're trying to vi

> All of the metal at a scrap yard I know of amounts to less than half that weight, for reference. That's not a great reference point when you're trying to visualize to pumped storage, as water is 1t/m3 while steel is up around 7 or 8. Also, 500t of steel at a scrapyard seems very small - 70m3? A better reference might be a back yard pool, which might be in the 30-40t range - so like lifting 15 back yard pools the height of your house to power a tiny AC.