OP: Are you THAT short-sighted? When TSHTF... where do you think you'll find the power to charge through a USB? The IDEA is to find a stove -or means of cooking- when the entire grid collapses.

I have a dual-burner propane model [still not a GOOD choice, since the propane will eventually run out], a charcoal grille, several foil buffet trays [that use canned, gelled Alcohol -aka Sterno- these are the cheapest and easiest to find, BTW] and finally, I bought an old-fashioned cast-iron HIBACHI [like we used back in the 1970's at the beach]... it fits very neatly inside my fireplace and cooks quite well.

MY ADVICE? RE-EVALUATE your personal needs and think a little further ahead when you have abslutely NO backup resources.