NextBillion - An Initiative of the William Davidson Institute at the University of Michigan

Wednesday, January 7, 2015

Millions of rural villagers around the world still cook with wood and charcoal, with all the limitations and inconveniences that implies. Women spend time and energy collecting and hauling wood, which contributes to deforestation and takes them away from more productive uses of their time. Worse, burning wood and charcoal inside homes produces extremely unhealthy fumes.

Biogas produced from organic waste, such as cow dung and farm cuttings is a good alternative, because it’s lightweight and clean burning. But it’s not possible to have a bio-digester—a system for breaking down the waste to produce biogas—in every person’s home. That’s too expensive and impractical. You need upwards of five or six households invested in a digester to cover its costs.

Katrin Puetz saw the potential of biogas for rural communities while doing her master’s thesis at a university in Germany. She wondered how to do the “last mile” of distribution from a central digester site to someone’s home. She came up with the biogas “backpack”—a sturdy bag to transport the gas.

Since then, she’s created a full line of products for villages to use biogas locally. First there’s a 2 x 5 meter bio-digester “system” for 44 pounds of cow dung a day. It’s a tank with an outer tent covering. Then, there are the packs which hold 1.2 cubic meters of biogas at a time (6 kilowatt-hours of energy or enough for four hours of cooking). And there’s a simple stove and several other parts.