Battery production capacity grows by 10x every five years. It was four years ago when I first heard that, and we are exactly on track still. In 2031 we will be at 20-30 TWh/year production capacity.

There are few things that grow this fast when it comes to manufactured things, atoms are far harder to arrange and scale than bits. But it's happening at a tremendous scale. Natural gas turbine production capacity is tapped out with long order queues, and so is battery production well into 2026, but only battery production capacity is expanding at breakneck speed.

Understand that only ~6 TWh of lithium batteries have been produced to date. As in, every single year of production combined adds up to less than 6 Twh. Moore's law largely stemmed from the fact that making a processer faster also meant making transistors smaller. Reducing the width of a transistor to a half, a quarter, etc. increased compute per cm^2 by double, quadruple, etc. Chemistry doesn't obtain that kind of exponential growth - we have hard limits on the number of joules we can store per gram of anode and cathode, so scaling up production means digging up more anode and cathode material out of the ground. The nature of resource extraction is that the easiest-to-exploit reserves are exhausted first, and continued production is contingent on accessing the progressively more and more inconvenient reserves. Maybe in 2030 annual global production will be 30 TWh - we'll know in 4 years. But there's a lot of people who probably don't want to make trillion-dollar investments gambling on that possibility panning out.

Regardless of your confidence in battery production's continued growth, I think you'd agree that if someone is making a calculation about the required amount of overproduction required to maintain a stable grid, they should at least mention that their calculation is contingent on provisioning tens of terawatt hours worth of grid storage.