Knowledge only is knowledge if it's proven.
Anything else said or written can only be speculation (even if it turns out to be true).
So proof, mathematical or otherwise, is not just desirable but should be mandatory in Wikipedia.
Of course, for quick reading, it could be separated from introductory text.
What surface does it take to fuel a car for a year. 1 hectare? Will there be any space left for anything else in the country?
Knowledge only is knowledge if it's proven.
Anything else said or written can only be speculation (even if it turns out to be true).
So proof, mathematical or otherwise, is not just desirable but should be mandatory in Wikipedia. Of course, for quick reading, it could be separated from introductory text.