Those TWH factories are being built right now. Multiple of them. Production ramp up is going to take a few years before they actually produce that much. But you can sort of do the math based on the number of cars they are selling. About half a million last year so that would be roughly a quarter TWH if you assume 50KWH batteries. Ballpark enough to keep Australia running for about a year if your numbers are correct.
That's last year. It's easy to see how they would grow production to a few million units in the next few years. So, at that point they are using TWH of production capacity that they are building right now in Texas, Berlin, Shanghai, and soon possibly India.
Of course the broader industry is growing quite rapidly to probably a few million unit sales this year and tens of millions by the end of the decade. So, definitely already into TWH/year territory right now. Taking care of Australian energy storage needs is not going to be an issue. About a million EVs would do the trick easily. Sadly, they are a bit behind on jumping on that band wagon but they'll catch up soon enough.