The UK has very little hydroelectric power and the undeveloped hydro resources are in remote areas of outstanding natural beauty (which is a shame because it's

The UK has very little hydroelectric power and the undeveloped hydro resources are in remote areas of outstanding natural beauty (which is a shame because it's by far the best option for base load renewables). The UKs current installed pumped hydro resources amount to some 28GWh. Clearly we need a multiple of that if that is currently required to balance a grid consisting of largely dispatchable power. Given that, I don't think my estimate of needing several hours worth storage is too far out. That was the first statistic I found. Even if we say current production is 200GWh of lithium battery storage, that isn't going to go very far if the rest of the world also need to create similar storage infrastructure.