Well, the wind blowing on some hill somewhere in europe isn't of much help, it needs to be diverse enough that some countries can make up for the entire lack of production of other countries.

I am not convinced there is much diversification. I just did some back of the enveloppe analysis to convince myself. I am using hourly wind electricity production data from this source [1] which is referenced on the europa website [2] (first source I found, I don't necessarily vouch for it). I only looked at 2014-2015 (the last two years of this time series), took the daily production at 2pm (seems to be peak production and peak demand), and then calculated a weekly average of the 2pm production by country for every day. I took the low points for the UK (arbitrarily, that's where I am now), and looked at the percentile of each country for those UK low points.

So the way you read this is for the week ending 28 June 2014, when the UK was at its 1% worst wind production across 2014-2015, at that time Norway was at its 15%th worst production, Sweden 9%th worst, etc. "15%th worst" means that the norwegian production for that week was below that level only 15% of the weeks in 2014-2015.

                     2014-06-28    2014-09-09    2014-09-16
  United Kingdom             1%            1%            2%
  Norway                    15%           21%           20%
  Sweden                     9%            0%           11%
  Netherlands                1%           19%           18%
  France                     2%            9%           15%
  Germany                   23%            1%           41%
  Italy                     63%            9%           18%
  Portugal                  32%            5%           60%
  Greece                    55%            5%            8%

so you do get some outliers (Italy and Greece in the first column, Portugal in the last), but overall, all the major countries are down at the same time, so it's not Portgual that will produce the wind energy for all the other countries.

[1] https://zenodo.org/record/4803353 [2] https://data.jrc.ec.europa.eu/dataset/jrc-emhires-wind-gener...