New Possibilities in Biochar Stoves

The 3 stone fire– the traditional East African Cooking apparatus found in millions of rural households. It’s simple and cheap, consisting of 3 large stones supporting a cook pot, with a wood fire burning underneath. The 3 stone fire is ideal for cooking ugali, the staple dish of the region (a thick paste of cornmeal and boiling water which requires quite a bit of force and leverage to mash). Unfortunately, the 3 stone fire is also deadly. It is the leading cause of indoor air pollution in the developing world, largely due to the smoke, particulate matter and assorted carcinogens produced during incomplete combustion. This pollution also disproportionately affects women and children, since men are not traditionally involved in preparing food in these regions.

Many bold efforts have emerged to combat the 3 stone fire over the last few years. We’ve seen a host of innovative stove designs come to market, as well as a variety of new, cleaner fuel technologies. These new technologies have been matched by a pledge of over $100 Million in funding from the Clinton Global Initiative and the Global Alliance for Clean Cookstoves to displace the 3 stone fire. Unfortunately, despite the best efforts of the West, clean cookstoves have faced an uphill battle. Through our work in East Africa, we’ve frequently come across a disappointing scene in many kitchens: A clean cookstove sitting idle, next to a roaring 3 stone fire.

Why is it that people would choose to cook with a smokey fire, when they have a cleaner alternative? From speaking with many women in East Africa, we’ve identified several problems with existing clean cookstove technologies:

  • They are not effective for cooking local dishes: Like any other kitchen gadget, a stove has to first serve the purpose of cooking food. African cuisine varies significantly from country to country, and often requires different cooking techniques. In East Africa, the process of mashing and kneading ugali requires a strong, stable cooking surface that many clean cookstoves cannot provide.
  • Burn time and intensity is not sufficient: Three stone fires get hot very quickly. People are unlikely to adopt a solution that takes significantly longer to achieve the same effects as the status quo.
  • The improvements in emissions are not readily apparent: There are huge educational barriers to clean cookstove adoption. Virtually all clean, biomass stoves produce some amount of visible smoke during start-up (sorry stove manufacturers, it’s true). As a result, many end-users do not understand or appreciate the differences in emissions between a 3 stone fire and a clean cookstove.
  • They require complex fuel preparation: Many clean cookstove designs require complex or costly fuel preparation systems (pelletizing, briquetting etc), which can make the cost of fuel prohibitive to the end-user.
  • Existing stove financing schemes have not worked: Many groups have tried to subsidize the cost of complex stoves to increase adoption. By giving away stoves at little or no cost, it is possible to quickly saturate the community. Unfortunately, it does not leave the end-user with a strong incentive to use the product.
  • Clean Cookstoves are perceived as foreign: East African culture has powerful undertones of solidarity. The peoples of East Africa have endured great hardship by maintaining a strong sense of community. Many people in these regions perceive that by purchasing goods from local merchants and artisans, they are investing in and enriching their community. As a result, the local market for fuel charcoal and locally-produced jiko stoves is exploding. Clean cookstoves, which are often mass-produced in other parts of the world, do not necessarily illicit this same sense of community enrichment.

A biochar-producing stove

On a recent trip to Kisumu, a large Kenyan city on Lake Victoria, we identified a stove prototype with great potential to satisfy the above criteria. This stove was designed by Dorisel Torres, a Cornell student in the laboratory of Dr. Johnannes Lehmann. Dr. Lehmann is the world’s leading expert on biochar, and head of the International Biochar Initiative. This stove runs on firewood, and operates like the highly-sucessful ‘rocket stove.’ However, users can load the stove’s ring-shaped chamber with raw, waste biomass (corn cobs, corn stover, sawdust etc) and produce biochar while cooking their meals. The stove then burns the pyrolysis gases produced by the waste biomass, leading to a hotter flame and reduced cook time. Finally, the stove has a sturdy clay lid making it perfect for cooking ugali.

Meet Beatrice

What’s more, this particular stove design can be fully assembled by local artisans. Beatrice is a remarkable local woman who runs an orphanage and school out of her house. Beatrice also maintains a small garden and runs a side business making pottery. She is able to manufacture these amazing stoves, totally by hand, using locally-available clay. While this stove design is only a prototype, it offers great income potential for local artisans like beatrice. It also offers a sustainable path to clean cookstove adoption in East Africa that might just work.

Beatrice's bean crop grown without biochar Photo Credit: David Guerena

Beatrice's bean crop grown with biochar. Photo Credit: David Guerena

Oh yeah, and it produces biochar! Because of its clay retort design, this stove generates a high-temperature biochar which is ideal for use as soil amendment. The above pictures were taken by our friend, David Guerena, a PhD student in Dr. Lehmann’s lab after 1 year of using the stove. David was very clear that the above results do not represent the results of any scientific study. They are merely informal, anecdotal images. In addition, Beatrice was not able to measure how much char she produces with the stove to apply to her garden. However, these results are nonetheless encouraging. An efficient, biochar-producing stove has the potential to produce enough char in one year for a small, one-person garden plot. Over the coming months, we will be collaborating with Dr. Lehmann’s lab to facilitate many exciting initiatives in Western Kenya, and hopefully spread technologies like this stove throughout the region.

, , , , ,

2 Responses to New Possibilities in Biochar Stoves

  1. Art Donnelly March 29, 2011 at 9:22 pm #

    Hi Jason,
    Thank you so much for turning me on to this clay anila style stove. My name is Art Donnelly. I am with a group named SeaChar.Org We are working with local partners in Costa Rica on biochar/improved cook-stove projects. We are using a very different approach. Our Estufa Finca is a large TLUD style pyrolyzer. We are just wrapping up a very encouraging pilot project focusing on the needs of migrant indigenous coffee bean pickers. Send me an email and I will send you more info. Or you find my Public Picasa Albums on-line.

  2. Art Donnelly April 2, 2011 at 11:34 am #

    Hi Jason,
    The SeaChar Estufa Finca team is in the last couple of days of editing a detailed report on our recent biochar/clean stove pilot project in the Santos region of Costa Rica. This was done with the involvement of researchers from the National University of C.R. and the U of Washington, Seattle. We recruited 32 migrant coffee pickers households to work with. The data set is small, but the numbers look very encouraging. We did surveying, monitoring, Controlled Cooking Tests. We are trying to figure out the best way to share it with everyone. It will be a BIG file. We are looking for funding to do a much larger study with an indigenous (BriBri) cocoa growing community in southern Costa Rica.