Bio-gas is one of the cleanest, but less used sources of energy around. It is clean because it does not give out smoke.
Bio-gas can be got from decomposing organic matter. In Uganda, animal dung and human excrement are the most commonly used.
The process involves the construction of an air-tight chamber called a bio-gas digester. This gas is then tapped through pipes for use in cooking and lighting.
To construct a bio-gas digester, you need to get experts at it because any poor construction may affect the processing of the gas.
After the construction, fresh animal dung is mixed with water or urea and poured into the digester. As the mixer ferments, gas is generated and transmitted to the kitchen using pipes connected to special gas stoves and lamps.
The system can light as many lamps as possible, depending on its size. In your case, however, two cows can produce enough gas for three lamps and a stove.
And then, whatever is poured into the bio-gas plant comes out later as residue called bio-slurry. This is a highly rich organic fertiliser and can also be used as animal feed.
