It's doable given a large enough need. But I don't think there's much of a need to do this. People seem to blindly assume this but you have to challenge the ass

It's doable given a large enough need. But I don't think there's much of a need to do this. People seem to blindly assume this but you have to challenge the assumptions they are making a bit. Grid storage is not about long term storage at all but about demand shifting so that you can shift over production when demand is low to peaks (evenings typically) when demand is high. That's it. There are some setups with multi day capability but essentially most of the market is about 4 hours or less. That's what's killing the demand for gas plants. It's not long term storage. People build gas plants for base load that is supposedly needed. But then they end up being pushed into peaker-plant roles because the demand for base load just is a lot less than assumed. The reality is of course that we actually have a lot of base load in the form of nuclear and gas plants. That's not going to go away overnight. We probably have more of it than we need. So as long as we have too much of that, demand for seasonal storage is not going to pick up. That might change over the course of the next decades. But it will be slow and probably cost driven. Can we build huge batteries that store many GWH/TWH of power? Sure. Factories are already producing batteries by the TWH per year. That number is going to go up pretty rapidly as more factories come online. There's a lot of potential energy stored in (mostly) fully charged batteries in cars, grid storage, etc. That number is only going to go up. A simple question: how much demand for seasonal storage is there actually? In gwh please. It's a simple question but I've never heard a coherent answer to it. As soon as you put a number on it, it becomes an engineering challenge that you can put a price on. Most of the reports on this front are based on very flawed assumptions. That's how you end up with stupendously large numbers.