I am currently approaching this world through the eyes of someone who may want to use it for a project. By chance, before we started the world-building project, I applied to a Swedish art fund for a LARP project with friends at Blivande. We call it Avantgrid: Joule de vivre! and it would be set on a spectacular post-industrial island in the archipelago of Stockholm.
We would like the “world” that this is set in to be very flexible and open to interpretation while sticking to the core principle. Ideally, we would like factions to emerge for interesting in-game dynamics - energy worshippers, energy smugglers, energy accountants, underground rebellions of those who reject the rules, hackers who find loopholes.
I have brought up the idea with my co-conspirators on this project to perhaps set this game in the world built by Sci-Fi Economics Lab. Of course, we should not adapt Extremistan to that specific purpose but it gives me a chance to look at the world through the lens of someone who might use it and expand on it.
First of all, the proposed world of Extremistan feels like an inviting place for this game. That is a good sign. We could create a new district that was run on this energy-starved economy. That is the alternative that gives us the most freedom. We could also imagine that one of the major districts implemented these rules at some point in the history of Extremistan. Among the districts you have proposed, perhaps The Covenant seems most likely to become swayed by a new interpretation of scripture that demands extreme energy frugality? This also opens up the question of how we wish to handle the timeline of Extremistan - will there be a history and sequence of major events that are more or less consistent and canon (like Star Trek before 2009) , or will we end up with endless timelines (Star Trek after 2009).
The porous membranes between an endless number of districts is a very good mechanism for the sort of LARP we imagine because it allows any player to create a character with exactly the set of beliefs and rich back-story they desire by simply making up a new district. This fits our vision well, as we are generally looking for a set-up that allows for a very high degree of experimentation and diversity around the theme. It becomes very easy in-game to explain away your quaint style of clothing or strange technology - you just arrived on the train from a far-away minor district. Indeed, the mechanism of the train itself becomes a great way to explain if new people arrive in the game or leave early.
As for the layers brought up by @Joriam, I am actually not too worried about the initial idea not allowing for enough co-creation. At least not if we allow for a very wide range of looks and feels for these districts. As I imagine the city, it would be the size of a small country. As such, it allows for an almost endless variety of landscapes - at least if the technological level is such that it allows for more or less total control over building floating islands overgrown with forests, fields of crops, and rolling hills. Is that what we are imagining? As you imagine it @yudhanjaya, could this island believably be a scene in a district of Extremistan?