"The sun is always shining somewhere and the wind is always blowing somewhere."
This is true, but electricity can only be economically transported about 1500 miles at absolute most (most source-load paths are significantly less than 400miles)
Grandiose plans of paving the Sahara for solar fall down on several points:
1: It's not ours
2: there's a lot of potential demand nearby (southwards)
3: The engineering of the transmission system alone would be the largest civil engineering project ever attempted by at least an order of magnitude
4: By the point of entry into Europe, you'd lose 3/4 of the power generated due to transmission losses