If van darnas is riding around in fuel spaceships...

[Catapult]

Does Eorzea even have electricity yet? Are all the light posts torches? Now, I dunno if it's just because of the graphics engine, but all the light posts I've seen in Thanalan don't flicker like fire light does, which means that at least Ul'dah may use some form of electric lighting.

Based on my memory from the botanist guild quests, Ul'dahn lighting is powered by Ceruleum oil.
The quest in question has you follow up on some research done by the alchemists on the use of local Gridanian oil as a fuel. The response you get is the aclemists' lack of enthusiasm along the lines of "why don't you just use Ceruleum?"

The answer of course being Gridania's desire to develop energy from renewable sources they can harvest rather than finite sources that are mined.

[indira]

i think they get there fuel from burning xbox-one's.