Improved Basic Earth Mound Kiln (IBEK)

Why to choose this solution?
Earth Mound Kiln (EMK) is one of the oldest and most commonly used kilns in Tanzania and East Africa. EMK has average efficiency of 8-15%. Carbonization time is eight days which requires continuous attention and cooling time is 24-48 hour on the average. Quality of charcoal produced is rather low. Improved Basic Earth Mound Kiln (IBEK) has efficiency of more than 25% and quality of charcoal produced is relatively high.
Savings per day or production:
IBEK has efficiency of about 20-25 per cent and the carbonization cycle time is four days, large pieces of charcoal are produced and there are no left overs. 4.5kg of wood is required to yield 1kg of charcoal with a calorific value of more than 31kJ/kg. Whereas with EMK, 7kg of wood are required to produce 1kg of low quality charcoal of calorific value of 26kJ/kg.
Cost in money and in own time to construct:
IBEK is a temporary structure; the size of the kiln varies from a few cubic meters capacity to over 100 cubic meters. One iron sheet to make the chimney is required, the price ranges from 15,000 to 18,000 Tsh (6.50 to 7.75 USD) Another item which may involve cost is man power.
Carbonization takes 4 days and cooling takes 24 hours then off-loading follows.
Maintenance needed:
During carbonization one need to monitor (every two to three hours) the process to ensure the kiln is well covered throughout and no air is getting into the kiln through its walls. Use soil to cover emerging opening around the kiln.
Resources needed in use:
Corrugated iron sheet to make chimney, wood, grasses and soil (locally available). IBEK requires minimum capital investment and comprises a few hand tools. These hand tools (axes, machetes, hoes, rakes, shovels, digging forks) are also commonly shared in other daily industrial and agricultural activities of the rural population.
Problems and limits:
More time is consumed while preparing and organizing wood in the kiln to minimize void space. Large amount of small pieces of wood is required to make apron. More grasses are required as the technology requires the entire piles of wood to be covered.
Where and how can you get it or make it?
Applied in Tanzania?s coast region and southern part but mostly practiced in Kilosa in the Morogoro region.
Skills needed to produce, install. maintenance, use:
Arrangement of logs, chimney placement and kiln covering needs a trained person. Monitoring of the carbonization process and charcoal off-loading need short introduction only.
How to use it:
How to maintain it:
Climate effect (if any):
Each ton of charcoal produced and consumed in Tanzania using traditional methods generates nine tons of CO2 emissions; there is less emission if IBEK is used. The chimney plays an important role in reducing air pollution by filtering the smoke. The improved earth mound kiln reduces the emission of harmful volatile substances into the atmosphere up to about 75 % (Bill, 1981).
Where it is used and how many users are there?
Used in Tanzania by more than 100,000 charcoal producers every year.
Why is it successful?
The quality of charcoal made from traditional kiln and IBEK are significantly different in terms of time of carbonization and weight of charcoal. A relatively small quantity of wood is used to produce the same quantity of charcoal produced in the traditional method.
If you can make it, a short description, typical problems, materials needed.:
Wood is needed to make charcoal.
How to make it (if possible):
Video is being prepared to be uploaded later.
How is it delivered and by whom?
IBEK has been incorporated in Sustainable charcoal production model which involves development of a village land use plan, which also includes demarcating land for village forest reserve. The village prepares a forest management plan and by-laws for managing the village forest reserve. The forest management plan designate areas for sustainable charcoal production equal to 10% of the total forest land. A Village Natural Resource Committee (VNRC) is established to oversee and manage the village forest land. One of the tasks of VNRC is to approve requests from charcoal producers and to ensure they follow sustainable charcoal production methods including use of IBEK.
Successful financial model
This model facilitates transformation of land which earlier was regarded as general land into village land and therefore gives villagers the right to own and benefit from fees and royalties from forest adjacent to them, which means that money which was earlier collected by central government remains in the village. The decision on how the revenue accrued will be used is made by the village assembly. In most cases villagers use the money for community development projects and forest management such as patrol costs.
What policies and strategies helped the success?
Tanzania National Forest Policy of 1998 which advocate for Community Based Forest Management and benefit sharing. Also Charcoal regulations and village by-laws.
More info:
Sustainable charcoal model leaflet at Transforming the charcoal sector in Tanzania, a policy note at
Name of the association uploading the case:
Centre for Sustainable Energy Services (TaTEDO)
When was the case uploaded? (YYYY-MM-DD):