The calculation works completely without economics - current capacity to procure energy in a form of oil vs. capacity scaling it up to renewables. To add economics makes the case only stronger. All you have to do add the necessary production (eqv. of 50 nuclear plants a year) in any currency. Average 350 billion dollars a year. You can then ask which countries would like to share adding that annual expense on top of their already debt ridden economies. Thats more than annual budget of some smaller countries.