Modified TV dish making charcoal from some black locust branches. When you heat a covered container and drive off the gasses, what you are left with is charcoal. You can either burn it or draw with it, or use it crumbled up in theory to filter water, and or as a poison antidote it is rumored. You can see the gasses escaping on right.
Now, if you were to add these gasses to a small propane or other flame source, you would be able to include the BTU's from the gas into your other fuel, making both available for cooking, heating or whatever. Please realize this is only a small batch system, but many of them can be combined or larger ones made. And it takes NO FOSSIL FUELS to make this charcoal.
This free technology could be used in many parts of the world where wood is burned inside buildings to cook. This leads to much lung disease and early deaths of people who are forced to cook inside their small dwellings. Making charcoal with the sun provides people with a more refined fuel that does NOT cause such damage to lungs, since much of the toxic gasses have already been exhausted when the charcoal is originally made.
Here in America there are a myriad of tv satellite dishes, and Post Peak Oil, or during emergencies, these can easily be pulled down from our roofs, and cover with a bit of glue and aluminum foil (as shown in example).
You MUST use caution and never leave one of these parabolics near any combustible materials, else you may find out you have burnt down your house. ALWAYS store a silvered parabolic upside down with the reflecting surface pointing at the ground.