Climate change mitigation and adaptation and poverty reduction is currently a core objective in almost every African country’s development agenda. In these countries, economic and social development cannot be achieved without adequate energy supplies.
Access to reliable energy sources is vital for the improvement of livelihoods especially in rural areas where majority of communities are living on extreme poverty and rely on firewood for heating and cooking. While reliable energy alone is not sufficient to eradicate extreme poverty, it is a vital for creating economic growth and improving equality.
The energy challenges facing Zimbabwe are urgent and daunting and requires alternative sources of renewable energy such as biogas and solar energy. Renewable energy sources can make a significant contribution to the country’s energy situation and at the same time reduce the cutting down of trees for fire wood.
How biogas works
Biogas is a mixture of gases, primarily methane and carbon dioxide produced by the biological break down of organic matter in the absence of oxygen, scientifically referred to as anaerobic digestion.
“The gases can combust or oxidized with oxygen in the air, resulting in the release of energy which can be used as fuel. Biogas production by the process of anaerobic digestion is popular for treating biodegradable waste because valuable fuel can be produced while destroying disease causing germs and reducing the volume of disposable waste products” says Martin Nkomo, biogas digester expert and mason.
The focus for bio-digesters in Zimbabwe is primarily on low cost systems that are easy to manage and simple to maintain, requiring no active heating system or mobile mixing mechanism. They can be designed to suit the size of a project from household level through to small and large scale producers.
Human, animal, and organic waste is fed into the bio-digester in an underground tank or other suitable holding vessel. Micro-organisms breakdown the waste, which releases a mixture of gases, primarily methane. The gas rises and collects in a domed ceiling or tube where it builds up pressure. A valve and a hose attached to the top of the tank pipes the gas directly into the house where it is connected to a gas stove.
When the tank reaches capacity, excess effluent is pushed out by natural pressure through a flow pipe and into a holding bin where organic garden waste, like leaves, grass can be added to create high quality fertilizer. In agriculture and small-scale livestock farming, waste can be used and transformed into natural fertilizer and fuel.
Biogas for heating homes
Environment Africa, a regional non-governmental organization, is actively involved in promoting alternative energy solutions while empowering communities in Mashonaland Central Provinces in Zimbabwe. With a pilot project that started in 2014 in Guruve, where the organization constructed three biogas plants and six household solar systems, quite a number of biogas digesters were built around the whole district, where other community members adopted the development program.
One of the beneficiaries of the bio-digester, Mrs. Nyanhete said, “I am happy that we now have energy for cooking and lighting all the time. It’s a resource that never runs out as long as we have cattle that gives out cow dung.”
The cow dung from six head of cattle is sufficient to feed the home stead digester.
“The process of feeding cow-dung into the digester is not labor intensive and anyone can do it. We feed 20 litre bucket of cow dung slurry (dung mixed with water) into the digester daily and this produces enough gas for our energy need for the day,” Mrs. Nyanhete said.
Mrs. Nyanhete also sees the practicality of using biogas at home saying that the gas provides instant heat and it takes less time to cook.
“Now we can wake up and make breakfast for the children before they go to school, in a short moment as compared to when we were using firewood,” she added.
Through the National Domestic Biogas Programme in Zimbabwe, in partnership with HIVOS, Ministry of Energy and Power Development, Ministry of Agriculture, Mechanization and Irrigation Development and Renewable Energy Fund, SNV promotes biogas to provide access to clean energy for cooking, lighting and productive use. The programme is currently active in Insiza, Chegutu, Goromonzi and Mvuma. The aim of the project is to improve lives, increase incomes of rural households and contribute to sustainable waste management and nutrient recycling. The Zimbabwe Domestic Biogas Programme started its implementing activities in January 2013. Using a market based approach; the flagship national programme has inspired the uptake of biogas digesters across Zimbabwe.
More than 70 biogas masons have been trained to take up the installation of biogas plants as well as 18 fabricators.
Because of the benefits of cooking and lighting with biogas, the programme has improved the lives of 1385 rural households. SNV has since introduced new appliances in the market which are currently being tested, including refrigerators, rice cookers, geysers and heaters that operate on Biogas. These developments will transform lives and help women and girls in particular.