On the glistening waters of Lake Victoria, an aquatic plant causes big problems. But a new technology is converting the weed-like invader into something very needed: clean cooking fuel.
Dominic Kahumbu and his team yank bunches of water hyacinth from the giant freshwater lake between Kenya, Uganda, and Tanzania. The plant grows rapidly. It can form thick layers on the water’s surface, shading out other aquatic plants and reducing the oxygen in the water as it decays. The process not only harms lake life but also helps bacteria and mosquitoes flourish, which in turn can pose health risks to local communities.
Thankfully, the decaying process also has value. The Creator ordained that as organic matter like water hyacinths breaks down, gas develops. He also saw to it that the naturally occurring gas appears other places too, like in compost piles, swamps, and the bellies of cows and other cud-chewing animals.
Kahumbu is CEO of Biogas International, a Kenyan energy technology company. His business is piloting a machine that helps quickly convert organic waste into biogas, a clean cooking fuel. These “anaerobic digesters” allow renewable biogas to generate heat or produce electricity.
Kahumbu’s project has so far provided 50 “digesters” to homes in the city of Kisumu in western Kenya. The machines allow families to switch from wood or charcoal, both of which can produce harmful “black carbon” particles. (See Cleaning Up Cooking Worldwide.) Those are dangerous to breathe in close quarters with little air circulation, according to the World Health Organization. Some families received a gas stove as part of the project, to replace their jiko—a portable stove that uses charcoal.
Tony Otieno boils a milky tea using biogas made from ground-up water hyacinth. “The gas has no smoke, no smell. It is much faster than the jiko,” he says.
“It’s so fast and I no longer worry about the rains finding me outside anymore, because I cook inside my own house,” says Margret Ongowe, Otieno’s 70-year-old grandmother.
The digesters designed by Biogas International use about four to six pounds of water hyacinth harvested from Lake Victoria to power a single cooker. But the $650 digesters aren’t affordable for most families in the city.
Biogas International is seeking investors to help fund the digesters. Kahumbu hopes more machines will help solve two problems at once: saving the lake habitat and providing cleaner cooking fuel for those who call the area home. He now sees the invading water hyacinth as “a blessing in disguise.”