According to [1], there were about 20 million cars registered in Australia in 2021. If we turn them all electric, with an average battery size of 50KW/h, we'll get about 1TW/h of storage that can be charged during periods of overproduction and feed part of their capacity back to the grid when needed.

Electric car sales are currently low in Australia, with ~2% of new cars sold in 2021. But they are growing exponentially: ~2000 electric vehicles were sold in 2018, ~7000 in 2019/2020 and ~20'000 in 2021. [2][3]

[1] https://www.statista.com/statistics/632547/australia-registe... [2] https://electricvehiclecouncil.com.au/wp-content/uploads/202... [3] https://www.theguardian.com/environment/2022/jan/31/new-elec...