You can power the entire globe if you took 1% of the Sahara desert and made it solar collecting. You could cover that area in today's solar technology at an approx. cost of 5 trillion dollars, or 10% of the world's GDP, or a little under what the US paid to bail out it's banks. It would work out 10 times cheaper than the equivalent power output of nuclear. And that includes cabling across the globe to deliver the power.
This is already happening in small capacity delivery with North African countries supplying Europe through cabling under the Med with clean solar generated energy.
All we lack really is ambition.
Sunny yes but not ideal one sandstorm and everything's covered