Assessment of Technical Potential of Agricultural Waste to Bio-Energy in Botswana

Abstract

"The global impact of energy demand and the unstable fuel prices to power national economies have not only affected the industrious countries but all countries and the most hard hit are poor and developing nations. The world is faced with the challenge of adopting the most efficient methods of energy use to preserve the reserves and full scale exploration and clean forms of energy is ongoing. In light of the global efforts an in depth study was conducted to examine the potential of agricultural waste to bioenergy in Botswana. Crop residues and animal waste were assessed for their potential to supply electricity for rural electrification using the Food Agriculture organization Bio Energy and Food Security Appraisal tools and approach. Agricultural production data for a period averaging 10years was collected from relevant stakeholders in charge or actively involved in production sector. The data was then used to map the amount crop residues available in Borolong, Panda and BMC Lobatse. Trips were made to the areas to inquire and gather information about other uses of the crop residues that remain in the fields after harvest and adjustment were made to cater for such uses and subtract the portion used for other purposes from possible energy pathways. The BEFS Rapid Appraisal method was used to determine the possibility of rural electrification through combustion and gasification. Bio digester was also considered for the supply of heat and electricity using animal waste as a feed stock. The three areas have the possibility to use animal waste and crop residues to produce electricity for rural electrification. The amount of crop wastes available are sufficient to power gasification and combustion plants and supply over 300 households with electricity in both Borolong and Panda. Nationally the bioethanol potential stands at over 2 million liters annually. If fully exploited Botswana can add bioethanol to its liquid fuels mix and have a blended petrol mandate. From crop residues sorghum straw is the most abundant in Panda and has an annual output of over 75 ‘000tonnes/year."