[Gasification] Gasifier fan

[Clement Aigbogun]

I have built yet another gasifier, an updraft. The design is such that a bed of charcoal would lay over damp materials(the water content of materials is far in excess of what may be found in any normal wood)
Now because I intend to ignite from under, I want to ask if the natural upward draft of heat would be sufficient to create the hot bed of charcoal which is already placed over these damp materials(these materials are inbetween combustibles-the first layer of combustibles provides continous upward heat draft) without having the need for a fan or a blower.
My problem with using a fan or a blower is that I may need to power it with electricity or batteries which are scarce commodities in rural Nigeria.
Has anybody on this list have success with operating a gasifier without using a fan or blower. By success I mean consistent engine grade gas output everytime the gasifier is operated. 
 Clem

PS- thank you for the help