Investigating The Potential Of Domestic Biogas Production To Enhance Energy Access In Uganda
Access to energy is recognised globally as a key factor for the socio-economic transformation of every country. However, even with this knowledge, many people worldwide still lack access to modern energy services. As such the use of traditional fuels such as solid biomass, with its associated challenges, remains prevalent especially in developing countries. The use of biogas has been promoted as a suitable replacement for traditional biomass fuels in many developing countries. However, despite the introduction of biogas technologies in Uganda in 1950s, biogas use has remained low in the country. The potential role that domestic biogas production can play in enhancing access to modern energy in Uganda remains largely unappreciated. This research was therefore carried out to investigate this role by assessing the biogas technical potential, identifying the most suitable biogas production technology and assessing the economic viability of biogas production at a domestic/household level in Uganda. Biogas, which is majorly composed of methane and carbon dioxide, is produced through the anaerobic digestion process from various biodegradable materials including animal manure, agricultural wastes, energy crops, and MSW. The common technologies for domestic biogas production are fixed dome digester, floating drum digester and tubular digester. To estimate the biogas technical potential at a household level in Uganda, data about the quantity, availability, composition and biogas yield of the available feedstock was used. The selection of the best biogas technology was achieved based on the assessments provided by biogas experts, masons and potential biogas technology users. The Priority Estimation Tool software, which is a multi-criteria decision making software employing the analytical hierarchy process method, was used to synthesize the obtained information and give meaningful results. The economic viability of biogas production in Uganda was assessed using the costbenefit analysis approach by evaluating the costs and benefits of the selected biogas technology over its estimated lifespan. For purposes of data collection, a case study of Wakiso district was chosen. Relevant data was obtained from potential biogas users, biogas experts and masons, and also from literature sources. Subsequent computations carried out using Microsoft Excel spreadsheets revealed that the biogas technical potential from livestock manure is 380.7 million m3/year while that from municipal solid waste is 62.2 million m3/year. The potential biogas users identified lifespan and capital cost as the most important technical and economic criteria respectively when selecting a suitable biogas production system. A fixed dome biogas system was subsequently selected as the most suitable domestic biogas production technology in Uganda. Domestic biogas production in Uganda was also found to be economically competitive with NPV of UGX 7,668,362; IRR of 37%; BCR of 2.2; and discounted payback period of 3.95 years. The results obtained indicate that the potential for domestic biogas production to enhance energy access in Uganda is high. There is therefore a need to actively promote domestic biogas use in Uganda because of the huge potential that exists in the country. The positive economic returns associated with biogas use can be a major driver to biogas production if the indirect monetary benefits such as time savings, improved health, improved agricultural production and environmental protection are clearly explained to the people.