You have just the one snake and no incubator? If it gets cold put the snake in a bag and put the snake bag down your shirt to keep it warm. At night put the snake bag into a tub and put that under your bedcovers with you. The tub ensures that you don't roll over onto your snake, or if your snake pees it doesn't wet your bed.
You would be better off finding a place you and your snake can go temporarily (e.g. crash at a friend or relative's house) if there is an extended outage, rather than trying to set up a generator for a small apartment. All you would need is a small tub with a very secure top, heat pad, and thermostat to become your snake's home away from home.