Biogas Stoves: How do they work?

This image of a biogas stove was provided by http://news.co.cr/a-well-grounded-young-tico-marcos-vinicio-lopez/3237/. 

To begin explaining biogas stoves, it is probably useful to first think about what "biogas" is? Biogas is essentially another word for a gas mixture that is predominantly made up of methane (CH4) and carbon dioxide (CO2). It is created as a byproduct when organic material decomposes in anaerobic conditions.  When the decomposition process occurs in an enclosed environment it can be captured and used as a natural fuel source. Biogas production for any scale requires a digester and a gas storage tank (depicted below). The digester holds the organic waste and water mixture, called slurry, that slowly decomposes to form biogas. The biogas rises into the storage tank and stays there until is needed.

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This image of a biogas digester and fuel unit was provided by http://puxinbiogas.en.alibaba.com/product/320459746-214346657/New_style_biogas_digester_plant.html.

Biogas has not been successful marketed on a large scale yet, but there have been many accounts of successful biogas usage in smaller projects. Several grassroots and nonprofit organizations (such as Heifer International and it's partners), have in recent years started biogas fueled stove projects to allow people in impoverished communities to have a sustainable way to cook their food and heat their homes. For people in these communities, biogas is a much cleaner alternative fuel source. It burns with minimal CO2 output and uses products that are readily available. Many of these communities use wood as a fuel source for their homes, but the demand for wood is often higher than the supply which causes deforestation in those areas. Wood smoke in homes has also been known to cause health problems for the inhabitants and anyway to eliminate health complications in countries where health care is not necessarily available is beneficial.

There are a host of possibilities that biogas fuel could offer the world as a renewable energy source. Biogas could become a fuel alternative in homes around the world. People could work to make it more feasible to produce biogas on a large scale and provide it as an energy source if people are not interested in installing the systems in their homes. If it spreads far and wide enough it could significantly reduce deforestation and all of the environmental problems that come with it. It is interesting to contemplate, even if it might not be entirely feasible.

Sources and Links:

1) Brief Overview of Biogas Production: http://www.wisegeek.com/what-is-biogas-production.htm

2) Heifer International: http://www.heifer.org/blog/tag/biogas

**I give my sincerest apologize for my two month hiatus, but as of this post, I hope to begin weekly posts once again.