> One thing I'll add here is that there are a lot of energy usages for fossil fuels for which we have no alternative. Aviation is a big one.

The status of "fossil fuels" isn't crucial to these uses, it's just cheaper. You can just make kerosene, but you wouldn't because you already use fossil fuels for power. However if you have abundant energy without fossil fuels and you want kerosene for some reason you can make it for $$$$