Just look at Texas, where windfarms get curtailed because there is not enough transmission capacity from the production area to the load centers.

It's slightly less sensitive in Europe (wind is more widely dispersed), but it is a bottleneck in some places, and most of the current investment in grids is meant to accommodate the growth of wind production. In particular, transmission lines from the regions near the North Sea to the rest of the continent are necessary. So far this is done on a country by country basis, mostly.

Wind power