It is a little more complex than that. You cannot only consider how big is a country or how big is its grid.
If the Europe would be hit by a solar storm, assuming that not all of it was hit we can recover the grid in about a month and the blackout would not be longer than maybe a week.

But a solar storm would destroy also everything else, so how big is the grid is really irrelevant when you basically have every other piece (excluded the few hardened enough) destroyed.