I’m only half kidding. I’m a bit of a prepper and I have lots of powerbanks and devices that charge from USB but besides idling my truck I really had no other way to charge any of them in case of a long-term power outage which seemed a bit of an oversight on my part.
Not like this solves the issue. 30 watts (under ideal conditions) isn’t much but it’s a start.
I get water from 800ft underground. Not a long term solution but being able to drink, cook, and bathe for a few weeks or months is going to be important. It is useful to be able to power the pump with batteries charged by the sun until enough people have died so I can migrate to a more tolerant climate without having to mad max it.