I see companies like Tesla and Generac are selling back up power solutions for home, to include solar. For convenience I know at least the Generac solutions work fairly well when maintained and run regularly.
Some other strategies for protecting food would be a supplementary freezer kept in the coolest part of the house. Keeping food separated and well packed can mitigate loss of cooling when opening the freezer. Block ice can supplement refrigeration as well as insulation.
For a simpler solution I found in the many power outages we experienced in Winter and hurricane season a good cooler ( ie yeti ) placed in the shade and wrapped with a good insulation, perhaps with thermal reflective qualities you can keep food and drink cold for long durations. Organize the content to keep open time to a minimum. Having made gear lists and review after action reports following events I noticed one item always crept to the top of the list. Cold beer turns out to be important indeed, now if you could just get your hands on a good thermal reflective insulation...
