[ksec]

If one day there is a battery for every house or even flat. That is double the capacity of Tesla power wall at half the size while lasting twice as long. Do we still need to upgrade the grid infrastructure?

I assume With that many buffer in place the whole thing should be able to self balance relatively easily. But I wonder if that is also a false assumption.

[aidenn0]

If EVs are competing with power walls for charge, then presumably you couldn't charge overnight, so a longer-than-normal heat-wave could drain all the household batteries.