Biodigesters, which convert organic waste and invasive plants into biogas and biofertilizer, are popular in Kenya and present themselves as a less polluting solution than firewood and charcoal. Companies have the wind in their sails, but the unaffordable cost for households remains a challenge.
At Biogas International, a Kenyan company specializing in energy technologies based on the outskirts of Nairobi, several experiments and research have been carried out for a dozen years.
With his team, the Chairman and CEO, Dominic Wanjihia Kahumbu, has notably developed, like other companies, small biodigesters which can be installed in three hours next to houses. Their owners can throw in a tube their organic waste, which then turns after a week into organic fertilizer and methane for cooking, used on a stove connected to a pipe.
“From the start, our main objective was to see how we could prevent people from cutting down trees to make charcoal,” said the man who worries about deforestation and forest degradation. He also wants to “divert” organic waste that pollutes rivers.
80%
Kenya, like other African countries, has a population that uses wood and charcoal extensively for cooking: 80% of households in the country depend on it as their primary source, which prompts several voices to be raised to develop sources of cleaner energy. According to the World Health Organization, these two methods are polluting and dangerous for health, and lengthen the time spent cooking. Nearly 20,000 people die each year because of their exposure to pollution, Kenyan authorities estimate.
As for the device making it possible to use methane for cooking, it “saves a considerable amount of time in a day”, adds the CEO of Biogas International. This is especially convenient for farmers, as they can increase their productivity by focusing on other tasks.
The company currently has more than 2,000 biodigesters in operation. Larger models of digesters exist, but institutions, such as hospitals or schools, are reluctant to switch to biogas. “The biggest barrier for biogas is financial,” says Josephat Chege, operations manager at Biogas International. Expansion is therefore complicated. “Low-income households are the ones who need biogas the most, but they can’t afford it,” he says.
Their small model biodigester costs nearly US$750 while the average monthly income is just over US$150, according to Kenya’s National Bureau of Statistics.
War on water hyacinths
Biogas International has partnered with pharmaceutical group AstraZeneca and the University of Cambridge’s Institute for Sustainability Leadership. Through a sponsored project, 50 household biodigesters were donated to households that are older or have certain challenges — such as a disability — in Kisumu, a town near Lake Victoria in western Kenya.
The employees on site kill two birds with one stone. They regularly go hunting for water hyacinths on the lake, a very fast-growing invasive plant that harms fish by reducing oxygen in the water, and which causes headaches for fishermen. They then grind the plants in a 20-meter-long digester, which supplies the building of a nearby non-governmental organization, as well as a community kitchen and other businesses.
“We have also installed bins in the twenty restaurants on Dunga beach and we collect all their food residues, underlines Dominic Wanjihia Kahumbu. They don’t have landfills and they used to throw them on the beach. »
At the smoky beach market, fish seller Eunice Anyango, who fry tilapia over a wood fire and sometimes use the communal stove, sees “a big difference” between the two. “Biogas is cleaner, there is no smoke. We don’t cough, we don’t lose a lot of energy, says the one who has been practicing her profession for a dozen years. The smoke gives us chest pain. »
Nearby restaurants are connected to biogas, which is less expensive than buying wood. But the energy provided is not enough to supply everyone and it is not easily accessible. Added to these challenges is the difficulty of convincing herding clans to equip themselves with digesters. “Still to this day, they refuse. The men kept asking me what their wives would do with their days if they no longer had to collect firewood,” Dominic Wanjihia Kahumbu drops.