If you power source is secure, freezing is the best way to preserve food. Cut vegetables into small pieces. Press into a freezer bag removing all the air. "Freezer" bags are thicker than "storage" bags. If you don't use a freezer bag, the dry cold will dehydrate your food in a way to make it unpalateable.
This is tomato sauce, lay it flat so it takes up less room.
This is beans cut into single recipe portions, for soups etc.
Ziplock freezer bags are expensive, and twist tie bags aren't easy to get airtight. For the optimum protection, with the least amount of waste and expense I have found this inexpensive vacuum sealer.