The answer to this fuel problem is pretty straightforward and the easy solution is using the fuel source that’s all around you, i.e: use natural materials, wood, cones, furns etc.

All these natural fuels will create heat to boil your water and enough heat to cook your food.

Of course, as always there are plenty of  wood burning stoves to choose from, and if you go right back they were very simple tin boxes with a hole to feed in some twigs. 

But wood burning stoves design has moved on:

Source link: https://www.ukpreppersguide.co.uk/solo-stove-lite-wood-burning-stove-for-camping-or-bushcraft/ by UK Prepper at www.ukpreppersguide.co.uk