how about the use of a AA battery and insulated wire to start a fire? If you have a wire, but no insulation, just wrap the wire with something. a bit of clothing, some debris, a hunk of tape. The tape is best, cause it can hold the wire in place on the poles of the battery, until it gets red hot (only takes seconds to achieve) The duct tape will burn readily, if it's shredded and piled up a bit, but really fine wood shavings/feathersticks, with a bit of pine resin, will also ignite quite easily, as will a little chunk of your T shirt. How many emergency fires do you imagine you will need to start? why not just bed the coals in the ashes? It will keep the fire for 8 hours, and you wont get to sleep longer than that, in emergency conditions. You'll be lucky to get 5 hours, mostly.