> Fermentation is a easy way to create your own fuel.

Not that easy. The problem is the crop growing and processing you must do beforehand, to get your feedstock for fermentation. I'm from Brazil. Here we have a large industry built around ethanol production from sugarcane. To this day problems like boiler explosions and people falling in sugarcane crushers are not entirely unheard off, and also poor working conditions in sugarcane fields. Not that easy.

Large agri-industrial ethanol production has lots of problems, yes, but small scale local production integrated with regenerative agriculture, as described and promoted in the example link, is a different system. It used to be common for farmers to "grow" their own tractor fuel.

Fermentation is a great way to create cheap or free fertilizer and garden amendments. Look up the works of yungsang cho or hankyu cho.