Among measures that have been encouraged is the use of green energy which minimizes production of carbon dioxide and methane that is tilting the atmospheric pressure leading to a lot of warmth.

It is against this background that the Kenya Ministry of Agriculture and Germany Technical Cooperation (GTZ) came together in 2008-2010 to support individual farmers to construct simple biogas projects in rural Kirinyaga County.

Thomas Kinyua, was one of the lucky small scale farmers to benefit from the renewable energy project that has changed life for better. On his one-and-half acre farm at Githioro Village in Kirinyaga Central district, he has 40 dairy cows that are properly housed which probably made him an ideal candidate for the project.

The land has since been registered as Uzuri Farm Ltd with a full time manger Jane Wairimu Mbeu, who explains how the biogas project has changed their lives.

“Before the idea of producing biogas was sold to us by the ministry of agriculture, we used to take the cow dung to the shamba where it was used as manure,” she says.

Biogas digester



Mbeu is not aware how much destruction the decomposing dung was doing to the environment as it released tones of methane gas. In 2008, however, GTZ through the ministry of agriculture proposed to construct a biogas digester that would not only tap the methane but produce cheap energy for the home.

The total project cost US$ 258 with the GTZ contributing about 25 percent of the amount while Kinyua paid the rest of the amount. Once the dung is collected from the cow shed it is carried with wheelbarrows to the first tank where it is mixed with one part of water and stirred.

“It must be added as frequently as three hours and left to decompose for some time in the digester with the methane gas settling in the upper compartment,” explains Mbeu.

The digester has a capacity of 18 cubic metres and its walls are enforced by bricks and cement to ensure it is air tight.

After the dung is digested it no longer decomposes again and it is removed and let to dry in pads outside before it is transported to the shamba as manure.

The final manure is high in urea and other nutrients needed by the plants with no harmful effects to the environment. Apart from providing the raw material for biogas, the dairy cows produce an average of 450 litres of milk per day which is sold to locals and major dairy companies.

Alex Kathigi, a worker in the farm, says that the gas produced is supplied to them through underground pipes and they no longer need to buy paraffin for their stoves.

“We used to spend over US$ 0.39 [600 shillings] to buy paraffin but since the biogas project was constructed we do not even know the price,” says Kathigi.

The methane has been piped and connected to seven cookers with two burners each and they have never gone for a day without fuel. The energy is also used to bake muffin cakes with a modified stove that uses less fire wood and methane and employs three people.

“Profit margins have remained consistent since we have saved on energy used by using biogas which we produce in the farm,” notes Kathigi.

Such cottage industries, according to youth leader George Kagori, are capable of employing hundreds of youths in rural areas and curb migration to major towns.


Ready to cook

Rolling out to others

Kagori says with the support of the government the projects should be rolled out in many areas to keep the youths busy and ensure they do not engage in drugs and criminal activities.

National Environment Management Authority (NEMA) Kirinyaga County Officer Samuel Nyaga contends that biogas if replicated in many homes would save the area large volumes of fuel wood.

He notes that every year thousands of trees are felled for wood as well as charcoal giving a lot of pressure to state and private forests.

Nyaga says although the initial cost of such projects is high, cheaper bio gas technology has been developed and soon it will benefit more farmers.

“We degrade the environment very much by cutting down trees to get wood fuel and biogas could supplement the demand if constructed by all farmers,” says the officer.

Muchangi Muriuki an environment expert notes that with only two cows, a farmer is capable of generating enough biogas for use throughout the year.

He says that farmers have traditionally kept animals for milk, meat, skins and bridal presentation but the need to adopt energy saving technologies has started changing things.

The managing consultant at DiverCT EHS Consult Ltd. points out that majority of people in developing countries rely on nature for survival yet they do not exploit it fully.

“Biogas is a naturally occurring gas and if well harnessed it would not only reduce the GHG effects but save our forests from being cleared,” he says.

Muriuki, however, says such small projects are yet to start earning carbon credits where individuals and organizations are paid for using such renewable energy that conserves the environment.

Methane is a naturally occurring Green House Gas (GHG) just like water vapor, carbon dioxide, nitrous oxide and ozone.

However certain human activities that include farming, mining, industrialization and other activities add to the levels of most of these naturally occurring gases.

Atmospheric temperature


Pastry baked with biogas oven

Atmospheric methane traps infrared radiation from the earth, which causes a rise in the atmospheric temperature, therefore contributing to global warming.

Muchangi Muriuki explains that once in the atmosphere, methane can linger for around 12 years making it one of the GHG that interferes with the ozone layer.

The environment expert points out that research shows that methane is 21 times more potent that carbon dioxide although the latter occupies 220 more times in the atmosphere.

“Human activities especially industrial related has increased GHG in the atmosphere which in turn led to global warming,” says Muriuki.

Frequent droughts, flooding, extreme colds and other weather changes have been witnessed as a result of global warming with clearing of forests adding salt to the injury.

When methane gas escapes to the atmosphere it reacts with ozone causing damage to the layer which in turn affects infra rays.

The gas is produced in decomposing refuse in dumpsites and dung through anaerobic process but unless it is tapped to use like in biogas the world has to bear the consequences of letting it free.

With reduced forest cover that act as carbon reservoirs global warming remains a major challenge to modernization.

Biogas contains about 60 percent methane and for it to combust it mixes with oxygen and produces heat used for cooking and lighting houses with no environment hazard.

Hundreds of farmers flock to Uzuri farm located five kilometers from Kerugoya town every year to learn the biogas technology and it is hoped more will take up the projects in future.