At a glance

A single 20kg bucket of food scraps and animal muck holds enough energy to cook every meal, all day, for a household of six to eight people. You just have to know how to pull the energy out. That is the idea Biogas International Limited (BIL) has been building on since it was founded in Nairobi in 2011, and fifteen years later its systems are installed across East Africa and beyond.

How anaerobic digestion works

Here is how it works. Seal organic waste inside an airless tank, and the microbes already living in it get busy, breaking the waste down and giving off a methane-rich gas as they feed. It is the same process that happens inside a cow's stomach, or in a compost heap quietly steaming on a cold morning. The only difference is that a digester captures the gas instead of letting it drift off. That captured gas is biogas, and it runs straight to a kitchen stove. The same gas can also drive a combined heat and power unit (CHP), a small turbine or engine that burns the biogas to make electricity and puts the heat it throws off to use as well. So one tank can light a building as easily as it cooks a meal.

This is anaerobic digestion ("anaerobic" simply meaning without air, which is the condition the microbes need), and it is one of the renewable sources already feeding the UK grid too.

The tech: FlexiTech (home) and T-Rex (bigger volumes)

BIL's household unit, the FlexiTech digester, sits above ground and goes in within three hours. No digging, no concrete, no construction crew. You feed it whatever is to hand: livestock manure, crop residues, market waste, even invasive weeds. If it is biodegradable, it is fuel. For bigger volumes, BIL runs the T-Rex (great name), a large-capacity digester built to chew through far more waste than a single home produces.

What you get out: energy, time back, and biofertiliser

Two useful things come out of the tank. The first is the gas, which replaces the charcoal, firewood, kerosene and LPG a household would otherwise buy or gather. That last part matters more than it sounds. Collecting cooking fuel can swallow three to four hours of a person's day, almost always a woman's or a child's, and a digester at home hands that time straight back. The second output is the leftover slurry, a nutrient-rich biofertiliser that goes back onto the fields and feeds the soil that grew the crops in the first place. The same material does two jobs and then a third.

"Waste is not a problem to be disposed of. It's a resource to be transformed," says BIL's Josephat Chege. The clearest proof of that sits in three very different places.

Proof in three places

In Dol Dol, in Kenya's Laikipia County, the land had been slowly losing ground to Opuntia, a prickly invasive cactus that crowds out grazing and spreads where nobody wants it. BIL installed more than 100 household biogas systems there and fed the cactus into them, so the plant choking the land became the fuel cooking dinner. Alongside the digesters came cactus choppers, beehives and vertical gardens, and the same ground that had been a problem started producing energy, fertiliser and food.

On the shores of Lake Victoria, the invader is water hyacinth, a weed that mats across the surface and clogs the waterways. T-Rex digesters eat it, turning it into biogas and fertiliser while helping clear the water it was choking. And in city markets, where organic waste usually ends its life rotting at a dumpsite, BIL's Trash 2 Resource model catches it first and runs it through a digester instead.

Built to stay local

What ties all three together is where the work happens. Rather than collecting waste and trucking it somewhere else to deal with, BIL handles it at the source, on the farm or in the market where it is made. And at every installation, BIL trains local people to fit and run the systems, so the know-how stays in the community long after the crew has packed up.

Recognition

BIL has spent fifteen years showing that the material causing a problem can be the same material that solves it. That work has earned it two nominations at the 2026 AD & Biogas Industry Awards: Micro & Small-Scale On-Farm AD of the Year, a category tem is proud to sponsor, and Net Zero Circular Solution of the Year.

Across thousands of homes, the same bucket of scraps now does three jobs at once, cooking the food, fertilising the field that grew it, and handing back a morning that used to disappear into gathering firewood. After fifteen years, that has stopped being a demonstration and become the ordinary way these communities cook.