While there are no direct uses involving DC power equipment and cooking in a self reliant situation, we include some information on the subject, as it might be useful. Using battery storage, for example, to run a resistance cooking device, is very inefficient. An exception would be a small microwave oven. While still a power hog, the run time is less than a resistance heating device, and may be applicable for some situations. Other than that, there are some options.
Cooking without electricity can be done with a variety of fuels, some of which you may already have and use. This includes propane, natural gas, coal, wood, charcoal, kerosene, etc. If you backpack or camp, and use fuel for your cooking device, find out any shelf life, and have enough on hand to last a while. If you have a propane barbeque that takes the 5 gallon tanks, there are larger capacity tanks available, or you can acquire several extra tanks, and keep them full. If you live rurally and have a large (200 gallon or more) propane tank for other purposes, have the fittings required to feed this to the barbeque (through the regulator of course). Most of the larger propane barbeques have a side burner, which may be very handy if you just need to prepare or heat a pot of something. You can wrap corn or other vegatable in foil (a good reason to have foil) and cook them over the grill portion. If you have an RV or trailer close by that has a propane cook stove, keep the tanks full, or keep spares. If you have natural gas, and a gas cook stove, and there are no line disruptions, you can still cook with it during a power outage. If you use wood for heat (or pellets), most wood stoves have a flat surface and can be used for most cooking purposes. In summer, this may not be your most efficient or comfortable method of cooking. There are boxes built for baking on top of a surface like this or on a camp stove surface, made by Coleman, I believe. There are boxes built to install in the 6 or 8 inch flue pipe most of the wood stoves use, which have a chamber inside for baking. The old kitchen wood cook stoves with the cast iron lined fire box on the side, and burners and an oven worked fine. Not very handy during normal times, but a nice condition 'decorator' on hand might be nice, if you live in a country setting.
Cast iron cooking implements have been in use for centuries. They are durable, reliable, but heavy. They have to be cured, and maintained. But, they retain heat, can be used directly over flame, set on coals, set in coals, etc., and have claimed health benefits. If you don't have any, they are good yard sale finds, as most people want stainless pots and pans. It's good to have quality, double bottomed stainless as well. We don't recommend any aluminum for cooking purposes other than foil, as there are suspected health risks with its use, and other limitations.
There are solar cooking devices that can be purchased, or built from plans, or you can build your own once you understand the principles and requirements. Not going to work in New England (or the Northwest where we are) in winter months. Some locations and times of year lend themselves well to this. Basically they are reflector boxes with a clear cover which trap solar radiation and concentrate it in the center of the box. There are other designs as well. Could be handy to have or know how to build.
Everybody needs some sort of cooking facility. Apartment dwellers may be limited to camping type equipment, or a barbeque. Not to worry. We recommend everyone have a propane type barbeque with several tanks, as this gives you immediate ability to cook/heat/sterilize, while you analyze the situation at hand. There may be other priorities than need more time consuming attention, and you can always use a barbeque. Keeps the heat out of the house/apartment in summer. If you have a wood stove, look into methods or other equipment you might add that allows the stove to do double duty in cooler months. Have some cast iron skillets, dutch ovens, etc. to augment your daily use stainless pots and pans, and know how to cure and maintain them.