Have you ever tried solar cooking? There are a few different options out there for cooking with not direct power (other than fire). While a lot of them are probably something you have seen before, we wanted to share this idea that we came across. A fresnel lens is an alternative option to solar cooking, but take caution as it is very powerful! Take a look at this post from Survival Mom to see how you can build your own.
See the post here: Build Your Own Fresnel Lens