I am curious about the power grid situation in Europe. Assume the rate of AC usage was as high as the US (or god forbid Japan), how far behind is the grid infrastructure from where it needs to be?
ERCOT (Texas) has daily swings of up to 50 gigawatts of power in the summer. I am pretty sure it is the most volatile US grid in terms of the demand side. A lot of the transmission infrastructure is purpose built for this exact problem.
They don't have any problem with impact from EVs on the grid, but god forbid AC units. One could obviously solve the peoblem with rooftop solar, which peaks just when you need AC the most.
There are massive distributed solar deployments (eg. people putting cheap solar panels on their roofs, often backed by batteries) happening right now, those should help offset AC demands quite nicely.