A great deal of effort into developing more efficient and less polluting stoves has been done over the last year, and the progress has been impressive. Some of the more advanced ones have charcoal as a byproduct. which in turn can be used as fuel, biochar or to produce "producer gas". Hedon (mentioned above) has a growing database of stoves.

Other sources of cooking fuel to be developed: Human and agricultural waste are best treated by anaerobic digestion into fuel gas. Aquatic weeds such as water hyacinth and typha can be digested with wastes, or briquetted into fuel or brewed into ethanol. Dryland weeds such as mimosa can also be harvested as fuel. If you deplete the weeds, so much the better! If you can't, your fuel source is renewable.