I read this article, which is about covering 1% of Sahara, to cover the entire world electricity need. It is awesome that we are not further away than this to power the entire world with clean energy.

Article: https://www.forbes.com/sites/quora/2016/09/22/we-could-power-the-entire-world-by-harnessing-solar-energy-from-1-of-the-sahara/#5e5b8ee3d440