That's a really popular idea on the internet because it's very easy to grasp, but the numbers don't work out well. The weights you can actually lift aren't much compared to the volume of a reservoir of water, and the heights you can lift them are but a fraction of the thousands of meters being discussed here. Yes, the concrete isn't going to require much maintenance, but the gearboxes needed are a significant engineering challenge. Pumping water or compressing air are a lot easier, and batteries are going to be hard to beat.
Except it is already being done by multiple companies [0], Energy Vault in Switzerland [1], Gravitricity in Scotland [2], New Energy Lets go [3], and Gravity Power [4]. All have raised substantial funds and are building.
Sure, pumped hydro has advantages, but has serious geographic limitations - you need a fairly ideal site. The key is that these can be built almost anywhere.
Good point, and good examples. Excited online discussion about companies like those are what I mean when I say it's popular on the internet. It's not impossible, it's just not the technology I would be betting on. To get a sense of what one is up against, you can work through the math comparing gravitational potential energy to electrical potential in typical batteries. I can't find a good link right now, but what I remember finding is that (in the ideal) a typical lead acid car battery has enough stored energy to lift itself into space! Conversely, if you wanted to store the same amount of energy as in a typical car battery, you'd need to be dropping that amount of weight from the top of the atmosphere all the way to the ground.
But the point about little progress by these companies still holds. ARES has been around for 11 years now and has one 50MWh project to talk about that covers 20 acres.
