Evaluation of biogas driven poly-generation system to reduce energy poverty and post-harvest loss

Ph. D. Thesis. ; Electricity has been described as “the missing link” of the sustainable development goals: as other goals are strongly linked to its availability. Currently, most rural communities are at the bottom of the energy ladder and majority of the dwellers are farmers who suffer from heavy post-harvest loss due to facilities deficiency. These remote areas, which often have plenty of biomass, are isolated and sparsely populated where grid connections are mostly economically or topographically unfeasible. The conventional solutions to rural energy usually look into electricity provision without linking the same to the farming activities which is the means of farmers’ livelihood. Thus, having little impact on improving farmers’ standard of living. To ensure clean energy access, a biogas driven combined cooling, heat and power generation system which harmonizes electricity generation with food drying and cold storage of agricultural products is studied in the context of the current renewable energy policy of the Nigerian government. Jagun village, an agrarian community in Oyo State South western part of Nigeria was used as case study. Primary and secondary data are used to assess the current level of post-harvest waste, biomass resources as well as energy demand. Wastes from a community cattle market and agricultural crops residue are quantified, characterised and assessed for biogas generation. Part of the biogas produced is used for household cooking while the remaining is used to power an internal combustion engine for electricity generation. Heat recovered from the engine is used to drive a cabinet dryer, an absorption chiller and maintain anaerobic digestion process. Besides, the effluent of the digester is assessed for the organic fertiliser. The models of the anaerobic digestion process, purification unit, internal combustion engine, drying unit and absorption chiller were developed in Aspen Plus software and the results are used to evaluate the economic viability of the system. The economic ...