Plot from WMO onshore weather stations close to North Sea averaging stations eestern shore (UK) and eastern shore (BE+NL+DE+DK). The wind is very correlated both on long and shore timescales.

More than half the wind capacity in Europe is in or close to the North Sea, so this correlation is of great importance. Imports and Exports of wind electricity cannot help a particualr country because the fluctuations are the same in the adjacent countries.

Wind Power Actual Generation Offshore North Sea

 UK and Netherlands+Belgium

(NB. UK Offshore generation also include Irish Sea)