Tadesse Abebe, a farmer with a medium-sized dairy farm in Sebeta, in Ethopia’s Oromia region has installed a biogas plant with a 10 m3 pit digester producing about 4 m3 of biogas per day. Biogas is increasingly becoming a low-cost alternative energy source since only an estimated 12% of the Ethiopian population is connected to the national electricity grid. Ethiopia’s biomass energy resource potential is considerable and includes biogas generated from agro-processing industries and livestock residues. With 77% of the country’s farmers owning cattle, many Ethiopians are eligible for biogas installation.
Accordingly, the current Growth and Transformation Plan (GTP) targets to install 25,000 domestic biogas plants in rural Ethiopia, mainly in Oromia, Amhara, Tigray and the Southern Nations, Nationalities, and Peoples’ (SNNP) regions. Besides providing alternative energy, biogas plants also provide crop fertilizer, help manage dairy waste and reduce greenhouse gas emissions as well as the burden, on rural women and children, of travelling long-distances to fetch firewood and the health risks associated with firewood smoke.
Tadesse and other farmers with biogas plants use biogas energy for cooking and lighting. But biogas, like natural gas, can be used in many others ways, including as fuel for engines to generate electricity. The average calorific value of biogas is about 21-23.5 MJ/m³, so 1 m³ of biogas corresponds to 0.5-0.6 liters of diesel fuel or about 6 kWh. A drawback in the use of current biogas technology is the high cost and difficulty in constructing the Sinidu fixed dome digester and storage and transport of excess biogas.
The Livestock and Irrigation Value Chains for Ethiopian Smallholders (LIVES) Project, which works across the dairy value chain – from milk production, input/service provision and milk processing/marketing to dairy waste management– seeks to use dairy waste management interventions to contribute to rural electrification by introducing alternative energy sources such as biogas.
The project has introduced a new biogas package which includes biogas electric generators, biogas pumps/compressors, desulfurizers, dehydrators, biogas storage bags and above-ground plastic digesters. The generator converts biogas to electricity enabling use of modern electric-powered innovations to alleviate the challenges of livestock production, marketing and human development in the rural communities of Ethiopia. Livestock development technologies that could be powered by the biogas generated electricity include small-scale milk machines, small scale milk coolers and, incubators and mobile phone-based advisory services.Rural communities could also access more information through television and other communication technologies powered by electricity from biogas.
Tadesse was willing to test the biogas electric generator, biogas pump and biogas storage bag at his plant. During the test, his plant produced biogas with a pressure of about 15.3 kPa, which is sufficient to run a biogas electric generator. The generator produces electricity with 227 volts, which is sufficient to run most household electric appliances. The biogas pump efficiently generated pressure which was actually beyond the measuring capacity of a gauge which measures up to 18 kPa. This pressure level was estimated to be sufficient to fill the plastic biogas storage bag within a few minutes. The bag enables storage and transportation of excess biogas that’s produced. LIVES is carrying out an evaluation of biogas technologies to assess the feasibility of portable plastic digesters and to find sustainable business models for the whole technology package.
The biogas package is suitable for households (individual, medium-scale dairies in peri-urban and urban areas) and communities (dairy cooperatives and groups in small-scale rural dairy farms). The technologies are currently being tested and will be demonstrated and introduced in the four LIVES project regions of Amhara, Oromia, Tigray and SNNP. The biogas technologies will also be introduced to producers and/or businesses which could pack and sell biogas.
Written by Solomon Gizaw (PhD).