Though dormant on the surface, the volcanic activity deep underground provides your house with a source of GEOTHERMAL POWER. You are not sure why your grandfather decided to draw from this source of energy when he had the UNLIMITED POWER OF THE ATOM at his disposal. But it has been this way for as long as you can remember.

Here’s what seems like a weird little throwaway from within the first thousand pages that doesn’t get answered until Act 5; the reason Jade’s house runs on geothermal energy and not Skaianet’s advanced fission technology is because Jake didn’t build it at all!

The seed of your [Kanaya’s] hive was deployed on the volcanic rocks beneath the sand with the assistance of your lusus and her remarkable burrowing skills, and you have lived there happily together since.

the building is organic technology that grows out of volcanic rock, presumably feeding on the magma to do so; a product of eco-friendly Sburb architecture rather than Skaianet’s careless abuse of physics.

I wonder, does that imbue the building with any of the same mythical qualities found in other items crafted from the lava of the Forge, like Dave’s cueball sword?