We built a woodgas digester at LEF in the early days. We found that our two-drum system would provide enough gas to cook a meal once every ten days or so. We were new to the technology. Probably better equipment and more experience would lead to much higher gas yeilds. We are concerned, however, about promoting village-scale biogas. Biogas is the same thing as methane is the same thing as natural gas. By whatever name, methane is a powerful greenhouse gas. If village-scale biogas became more popular, that could be an issue. Leakage from millions of small digesters is a problem that is hard to quantify. Biogas also needs daily feedstock, which is harder to find in urban or semi-urban environments.For these reasons, we are currently pursuing high temperature solar storage. (See solar cooking.) If we can make that work at a modest pricetag, it would be a very adaptable technology that would work without feedstock. It would work the best in middle lattitudes, where many of the world's lower income peoples live.
Biogas Burner in Action
Two Drum Biogas Production System