Our biogas system when it was working.

After last week’s Report from Kenya on Firewood (see here), I received a good number of comments and questions. So I thought it would be best to post another Report in response to cover additional issues. Note that the intent of the former Report was to indicate what people in the rural areas like Lumakanda use for cooking. It did not cover many other possible cooking methods that have not substantially caught on.

A number of people commented that there are a number of solar cookers available, some of them quite cheap. I have seen some of these and they have not caught on. The first reason is that they do not give a hot flame so it is impossible to cook the main dish of ugali. The one I saw could slowly cook rice, but then it took a long time and if the sun went away because of clouds, the pot had to be moved to the fire. This is the main impediment to all the wonderfully ingenious ideas developed for rural Africa: for one reason or another they are not acceptable or better than the old ways for the person doing the cooking. Note that I said in my previous report is what is needed is a cheap solar powered electric cooker. This will need a sufficient battery backup and yet be cheap enough that it is economical for people to purchase it.

Another reader remembered that we had a biogas system and asked why I didn’t comment on it. It is pictured at the top of this Report. Biogas is not used by people in our area. First, the system we got cost $750 so it was out of our range for most people in our neighborhood. There are cheaper version which are no more than a thick rubber balloon. Second, the system we bought was supposed to be sufficient to cook for 3 or 4 people. When it was doing its best, I estimated that it was only producing about half of what was advertized. This is another problem with innovations: the results are inflated so the purchaser is disappointed and will not recommend the innovation to others. Word of mouth is how an innovation is rapidly adopted and a bad reference will end that innovation. Lastly, after we had the system for about four years, one night we heard a loud bang and we found that the bottom tank had burst. That was the end of our biogas experience.

We know a Quaker family nearby who have over a hundred acres and about 25 cows. They built a much larger, underground biogas system. They also found that the system did not live up to its billing and soon abandoned the system.  

Elijah Kariuki spreads briquettes outside his plant in Majengo within Nanyuki Town. [Jacinta Mutura, Standard]

One new system that I have seen work is briquettes. These are made from paper, sawdust, crop residues, and other organic matter. These then can replace charcoal in cooking. They burn brighter, longer, and produce less smoke.

Another reader questioned the fact that the dead branches and wood if left on the ground would lead to more top soil. Unfortunately this is not what happens in a hot climate without a winter to slow down decomposition. African soils have almost no topsoil or organic matter unless cow manure or compost is put on the field shortly before planting. Organic material decomposes quickly helped by termites and other insects who feed on the leaves and wood. While termites are everywhere – when they fly out of the soil in clouds to mate, the children and some adults love eating them, kumbekumbe as they are called – while earthworms are rare.

One of the major uses of firewood is to burn them in the kiln that hardens the bricks. It takes a lot of big logs to make the fire at the bottom of the kiln. When too many trees were being cut down around Kigali, Rwanda, the government banned the burning of bricks with firewood. This ban began a number of years ago and has been quite effective as the trees near Kigali are now growing to substantial girths and heights. One reader noted that around the town of heavily populated Kakamega, stumps of trees are dug up and used for firewood.

One Kenyan friend on Facebook commented that he sells firewood to schools. Growing and cutting trees for firewood is an additional source of income for farmers here and those who do the cutting, transport, and selling of firewood.

In the near future in rural Africa, I see little possibilities of replacement of firewood as the major cooking source. Chimneys, better stoves, and other innovations may cut down on the amounts of firewood needed and the smoke it produces. These can reduce, but not eliminate, the drawbacks to cooking with firewood.


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David Zarembka

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Reports from Kenya: www.davidzarembka.com/

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