> There's also coal -> oil, if you've got some hydrogen handy. Which only works if you already have a technological civilization. The Germans were able to do t

> There's also coal -> oil, if you've got some hydrogen handy. Which only works if you already have a technological civilization. The Germans were able to do this because they already had a large industrial base. The South Africans were able to do this because they had an industrial base, and could find expertise internationally if needed. If you're living with 19th century technology (16th century?) you don't get to do coal-to-oil. These problems simply aren't solvable in the situation we're talking about, and you seem to mistake the fact that you can think of solutions for them with 21st century technology means they are universally solvable. That's not even close to true. If civilization stumbles, it dies.