Feel free to share your ideas!
How about to have some types of civilizations? You can develop thanks to analogue of fuels(algae, if it is, or something other), thanks to oil, or thanks to microbes (or something similar). All ways have their pros and cons. When you use oil, you develop fast but with with disastrous consequences (up to environmental disasters, if you don’t take action). If you will use analogues of oil or fuel, you will develop slower than with oil, but after the threshold you will develop faster and faster. And that without disastrous consequences.
Yeah I think it would be really interesting to see how a civ would develop without oil. I’ve heard people argue that if civilisation collapses now then it will be super hard to rebuild because oil is so much more scarce now.
I heard in one TV program: that people will use algae, if will no oil. And another idea, civ in style steampunk. It will be with steam engines, airships and other things in steampunk style. I think, that it will be cool!