That's a fairly old statistic to pick, not sure if it was intentional or not, but the reality is lithium battery production has grown significantly since 2016 and shows no signs of stopping. The largest manufacturer in China, CATL is estimated to grow its capacity beyond 307GWh by 2028 [2].

"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...