It bothered me at first, but I think it’s about greenhouse gas emission. For example, methane is another power source, with legal restrictions depending on the “cleanliness” of the gas when burnt. I don’t remember whether biofuels are still used at the time of the story.
clemux
Karma: −6
You’re probably not rational enough, then; see point 3 of lukeprog’s post.
This is the purpose of Freeciv’s variant Longturn. (Freeciv being the open-source game inspired—mostly—by civilization 2.)