Garbage-fed community cooker cuts wood use, energy costs

Source: Thomson Reuters Foundation - Tue, 10 Apr 2012 15:45 GMT
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KIBERA, Kenya (AlertNet) - At 9 am, boiled-maize vendor Janet Atieno leaves her house in Laini Saba village in Nairobi’s sprawling Kibera slum with a sack in one hand and a stick in the other. Her mission is to collect solid waste that she can exchange for cooking time at a community facility that makes use of garbage as fuel.

“For many years, I have used either charcoal or firewood to boil the maize. But the cost of these forms of energy has become unbearable,” said the mother of four, explaining why she decided to start picking up rubbish to redeem at the community cooker.

The cooker is based around a simple incinerator for dry solid waste, which burns at more than 800 degrees Celsius, with a very high combustion efficiency of up to 99 percent, according to its designers. The heat is channeled to nine cooking plates, used by local people to make food for commercial and domestic purposes, as well as for heating water.

“The main aim of constructing this facility was to help slum dwellers manage their solid wastes sustainably, and earn from it at the same time. But there are other advantages too,” said Janice Muthui, coordinator of the Community Cooker Foundation, a charitable trust set up by Planning Systems Services Ltd., the architectural practice that invented the cooker. “Whenever the cooker is on, it saves the equivalent of several tonnes of charcoal and firewood, which are the main sources of fuel in Kibera.”

With financial support from the U.N. Environment Programme (UNEP), the company helped local artisans build the prototype cooker in 2008 in Kibera, one of Africa’s biggest slums, on behalf of a community-based organisation called Ushirika Wa Usafi Kibera (Fellowship for Cleanliness) Laini Saba Kibera.

The group, which has around 230 members, also provides commercial bathing services and toilets for slum dwellers, and solid waste management.

Nairobi-born Jim Archer, chairman of Planning Systems Services, told AlertNet he first started toying with the idea for the cooker back in the 1980s because he was disturbed by the growing mountains of rubbish he saw around him in Africa, where garbage collection is often poor.

“If I could find a way of heating it to the point where people could use it for cooking – and given the high cost of fuel wood, and the fact that trees are increasingly scarce – it would mean a sustainable source of fuel on the threshold of every low-income community on Earth,” he said.

The problem with the first model in Kibera was that the temperature in the firebox was too low to eliminate toxins from the rubbish. Then Archer’s team met a local blacksmith, later dubbed “Firebox Francis”, who suggested a technique that involved dripping sump oil and water onto a super-heated steel plate.

That boosted the temperature to 850 degrees Celsius, enabling the cooker to produce toxin-free smoke and ash from burning plastic and other waste materials.


Environmental Resources Management (ERM), an international consultancy, has calculated that, if operated 24 hours a day, the community cooker could save the calorific heat equivalent of burning around 2,400 mature trees over one year.

More than 80 percent of Kenya’s urban dwellers, many of whom live in poor, informal settlements, use charcoal made from wood as their primary source of energy, according to government statistics.

Their heavy dependence on wood for fuel has contributed to the rapid decline of Kenya’s forests, with negative effects for the local climate, wildlife, water sources and forest dwellers, says the World Rainforest Movement.

On average, burning 2 kg of dry wood emits 1 kg of stored carbon, according to Vincent Onguso Oeba, head of the biometrics division at the Kenya Forest Research Institute (KEFRI).

“Considering that charcoal is largely made of carbon, it becomes environmentally friendly to substitute it with rubbish, because it saves a substantive amount of carbon from entering the atmosphere,” the research scientist said.

In Laini Saba, Atieno needs 6 kilogrammes (kg) of charcoal each day, at a cost of 180 Kenyan shillings ($2.50), to boil 80 kg of green maize for her business. She uses a further 2 kg of charcoal for her domestic needs – adding up to some 240 kg of charcoal each month.

“But when the community cooker is on, all I need is 90 kg of rubbish per day to earn cooking time that is sufficient for all my commercial and domestic needs,” she explains, adding that it takes about two hours to collect that amount of waste.

Not only is she helping clean up the local environment, but when the fruits of her labour are burned in the cooker, she is also contributing indirectly to forest protection.

“The effect is multiplied by hundreds of other slum dwellers who seek to do the same in order to get free cooking time to save on their daily costs of living,” said Muthui of the Community Cooker Foundation.


Bernard Manano Asanya, project clerk for the group in Kibera, said the cooker is lit three times a week, and community users either ‘pay’ 90 kg of solid waste for a one-hour cooking session or Sh10 ($0.12) per 15 minutes. Group members, most of them women and youth, are asked to bring in rubbish every Friday to be weighed.

The project employs seven young people who sort the solid waste. They remove objects that can be recycled, including glass and some plastics. Food and plant waste, such as banana skins and potato peelings, are separated out too so they can be used for making compost. The rest is burned in the cooker.

In February, the community cooker was awarded the inaugural World Design Impact Prize by the International Council of Societies of Industrial Design (Icsid).

Yet, while it is providing a valuable local service, Archer said the cooker hasn’t been easy to maintain, not least because of the violence that erupted in parts of Kenya after President Mwai Kibaki's disputed re-election at the end of 2007. The fledgling cooker was unharmed during the political unrest, but some of its early supporters fled Kibera, including Firebox Francis, disrupting the system being established to operate it.

Inventor Archer recognises that, having finessed the technical design, the social aspects of managing the cooker’s operation will be key to its success. The foundation is now working with development partners, including UNEP and non-governmental organisations, with the aim of rolling out the community cooker beyond Kibera.

With simple modifications, it could also be used to distill water, smelt metals, generate electricity, bake clay products, run refrigeration and dry maize and millet, according to the foundation.

Orders have been placed for cookers to be built in Karagita slum in Naivasha in Rift Valley Province, in Nairobi’s Kangemi slum, and in Kisumu East in Western Kenya, Muthui told AlertNet.

And UNEP has identified 20 to 25 Kenyan government schools across the country where it hopes to install the cookers, Archer said. He estimates that savings on fuel wood and charcoal would pay for the cooker’s set-up cost – under $10,000 – within five years.

“If you could replace the existing cooking facilities in Kenya’s 25,000 (primary) schools, the amount of trees you could save would be mind boggling,” he said.

(Additional reporting by Megan Rowling)

Isaiah Esipisu is a freelance science writer based in Nairobi. This story is part of a series supported by the Climate and Development Knowledge Network.