I installed a few outlets last year which claimed to offer USB-PD at 18 watts. They were certainly more expensive than any other kind of receptacle, but not so

I installed a few outlets last year which claimed to offer USB-PD at 18 watts. They were certainly more expensive than any other kind of receptacle, but not so much that I remember what I spent on them. I don't think anyone would switch the wall voltage altogether; not in one generation, at least. But a majority of the devices we plug into AC outlets these days convert that power to DC before doing anything with it, and a majority of those devices do so using USB; so one could imagine that a house which had solar panels and batteries could also have DC power wiring and dedicated USB-PD receptacles, skipping the inverter and all the rectifiers.