I do not know, whether this is true, but: When I was in school, we learned in geography class, that one could power the whole EU, if we occupied some area of the Sahara desert with solar panels, at least when looking at raw energy output, disregarding day night differences and possibly hot and cold environment that a desert is.

I guess humanity is still not ready for such projects of enormous cooperation between countries, or, that there are too many things in the way, like said temperature rise at day and fall at night, the vast distance the energy would need to be transported (is that a problem?) and maintenance work somewhere in the desert. One can still hope, that some day we will be able to think globally and solve problems that way.