Making a grate for a stove

For centuries ‘injera’, a pancake-like bread served with most traditional Eritrean dishes, has been cooked on simple clay stoves.

These stoves are smoky and dangerous to use and inefficient in their use of woodfuel, which contributes to deforestation and rural poverty in Eritrea. The Renewable Energy Centre (REC) has designed a new and improved stove that is more efficient and safer to use. 

The new stoves mean there is no smoke and no disease from the smoke. In two years, I have seen the local trees recover from overuse. We used to spend one and a half hours a day collecting wood. We were upset when we had to cut green wood, as the Ministry of Agriculture said it was illegal. Now we can use dry fragments and straw.

Berektaeb Teklahaimonot, Adana village

Background

For centuries, the cooking of ‘injera’, a pancake-like bread served with most traditional Eritrean dishes has been carried out on simple clay stoves, built over an open fire. These stoves - or mogogos - require a lot of woodfuel to complete the cooking process. 

Eritrea is currently experiencing a rural energy crisis, whereby demand for household energy has outstripped supply. Biomass, including wood, dung and crop residues, is the source for 80% of Eritrea’s total energy use and yet its average efficiency is only about 10%. The combination of high demand aggravated by low use efficiency has contributed to deforestation and rural poverty. With increasing scarcity of woodfuel, the distance covered to collect wood has reached 10 km in some rural communities. The combustion of biomass fuels in open stoves also causes eye infections and respiratory problems, particularly amongst women and children.

The REC project has designed a new and improved stove for the cooking of ‘injera’ which is more efficient and safer to use. 

The technology

How does it work? 

People in rural Eritrea use three different types of stove: the mogogo stove for injera; the mok’olo, a large steel plate for cooking disks of ‘hard’ bread, made from maize flour; and a smaller stove for boiling water or making sauces. The improved stove developed by REC incorporates all these aspects in a single unit. 

An improved stove is made with three combustion chambers, one for injera, one for hard breads and one for sauce. The appropriate combustion chamber is used, depending on which item is being cooked. A metal or woven grass cover is placed over the cooking plate, when injera or bread is being made, to retain the heat and to ensure even cooking

The combustion system consists of a primary air inlet that is tapered to accelerate the air flow under and through a grate, to ensure complete combustion of the fuel used in it. Exhaust gases are led to a chimney, which has a damper valve, so the draft can be controlled. The improved stove can make use of small twigs, agricultural residues from around the village, and dried cattle dung, whereas the old stove required thick tree branches. 

Sticks burning inside a stove.

The technology in more detail

An air inlet at the base of the stove leads air into a large, cone shaped ‘air accelerator’ and then on up towards a cylindrical fireholder. The base of the fireholder is a large, circular ceramic grate punctured by small tapered holes. These holes are wider at the bottom than the top, which further accelerates the air flow into the fire. The holes also allow ash to fall to the floor, to be collected later. Once the fire has been lit, the fireholder is isolated by sliding down a metal door. The sides of the fireholder are built with specially designed curved ceramic bricks giving it its cylindrical shape. These bricks are hollow and filled with insulating ash or sand to minimise heat loss to the surroundings.

How is it manufactured, promoted and maintained? 

To ensure uniformity and quality of construction, the project makes metal moulds for stove parts in local metal fabrication shops and then distributes them to the installation sites. Previously the hollow baked bricks and grates were made centrally.  Now, by providing metal moulds to the villagers, bricks and grates can be made by villagers themselves from local clay.  

REC staff form the women in a target village into groups of about ten. Two of the group are then trained in making the stoves and are given the steel moulds to use. These two women then train the other women and help them build their own stoves. The use of moulds helps reduce the overall cost of the stove, but also gives people ownership of their stove as well as developing a strong community spirit as people work together in construction.  A careful record is kept of each village that has received the training for the stoves. A selection of stoves from each village is field tested for efficiency by REC staff. This ensures that the design has been followed properly by the villagers. 

Some of the metal parts will corrode with time, but can easily be replaced.  The mud parts should remain in good condition, as long as the stove is being used and looked after. 

Weighing injera bread.

Environmental benefits 

Wood and greenhouse gas savings have been monitored through a number of independent verification visits. Savings vary, depending on how much wood and how much residue people use with the new stove, with measured savings between 1.9 and 4 tonnes/year CO2 per stove. 

People can now collect the fuel they need from bushes around the fields, residues and dung, and do not need to go to areas with larger trees. This, combined with an active reforestation programme, is helping to reforest the country.

Social benefits 

Rural women like the design of the new stoves, and often decorate them with elaborate paintings. Cooking with the new stoves is much quicker and the food is better quality. The quicker cooking time means that older children can get off to school with a good meal and do not have to spend time collecting wood with their family. 

The insulated walls and combustion chamber doors also mean that the outside of the stove stays cool, so it is much safer for small children and babies.  The new stove reduces indoor smoke pollution and hence respiratory and eye complaints. 

Economic and employment benefits

Some of the women who have received training in making and constructing the improved stoves can make a good income by making the parts and assembling the stoves in the towns.

Potential for growth and replication 

Demand for the new stoves appears to be strong.  People come to villages where women are being trained and asking the extension workers to provide them with stoves as well.  REC aims to provide an improved stove to all 340,000 rural households The main constraints to growth is the funding to train and employ extension workers and provide moulds for bricks. The style of stove is very specific to Eritrea and Ethiopia.  However, the basic design parameters could be adapted and REC is very keen to use the design of the new stove elsewhere.

REC is also developing other cooking equipment, such as a more fuel efficient charcoal fired coffee stove, and a fish cooking stove for use in the coastal strip area, and starting work with other renewable energy technologies.