> But it takes so much dam place. Does it? If you use iron instead then we only need to know that it has eight times the density of water. Multiplying a volume

> But it takes so much dam place. Does it? If you use iron instead then we only need to know that it has eight times the density of water. Multiplying a volume by eight is not a lot; it's only twice the size in length, width, and depth. So let's imagine replacing a typical hydroelectric power station [0] with a 'gravicity' system. Supposing the same depth you need a system of about one third of its length and its width and then fill it to the brim with iron. And of course do not forget to install cranes that are able to lift this iron to another space about 200m lower and back up. By the way, for concrete blocks it would only be a volume factor of 2.5, which would mean about 36% more in length, width and height. All in all, the amount of space that can possibly be gained with these systems seems pretty minimal to me. [0] https://en.wikipedia.org/wiki/Taum_Sauk_Hydroelectric_Power_Station https://en.wikipedia.org/wiki/Taum_Sauk_Hydroelectric_Power_... Edit: care to explain the downvotes?