"In 2019, LG Chem had the most lithium battery production capacity at over 50 GWh. LG Chem [is] increasing EV battery production capacity to as much as 110GWh by the end of 2020."
The design of a modern grid with battery storage would change as well - no reason to have singular giant storage plants. A mixture of solar, wind, and hydroelectric with distributed storage doesn't need to self-sustain 30GWh of storage, it needs to be able to smooth distribution and handle peaks. It'd be far more honest to look at seasonal average loads versus peaks, plus a buffer.
[1] https://energycentral.com/c/ec/world-battery-production
[2] https://www.statista.com/statistics/1103401/predicted-lithiu...
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.
UK current electricity demand is 30GW. So the demand for one hour is similar to the entire lithium battery production for a whole year.
How many hours worth of storage would we need to balance the energy grid using only battery storage? Off grid homes usually aim for around 3-7 days worth. Obviously that's excessive for a whole country where weather conditions vary across the country but I'd think several house would be required to account for peak in demand at times of low production.
Realistically distributed storage and load side control I think are more likely to be a bigger part of making it work.