Questioner
For the light-lances, where do they get their power from?
Brandon Sanderson
They come from the same sort of place that everything's getting their power. You know, little micro-engines that are basically fantasy-ish. They're... It's super advanced hyper-engines. I think I worked something out where they using acclivity stone in some way. They're like Brandon's versions of Asimov watches with atomic power. They're just fantastically far-future power sources. Otherwise, we couldn't make any of this work. Like, the whole shell around Detritus and stuff. We needed a cheap and powerful energy source.
Questioner
Exactly. They're just like little bitty things.
Brandon Sanderson
They're basically fantasy novels with spaceships.