Missed environmental benefits of biogas production in Zambia

Abstract

Biomass waste such as municipal solid waste, crop and forest residues, livestock waste and other organic wastes can be environmentally unsustainable if not properly handled. However, the same wastes could bring about environmental benefits and solve the energy poverty problem that Zambia is going through if used to produce biogas. Decomposition of livestock manure, direct combustion of woodfuel, forest residues, municipal solid waste and crop residues, chemical fertilizer production and application to managed soils emits a total of 2357 Gg CO2 equivalents into the atmosphere (excluding biogenic CO2 emissions) and results in nitrogen losses of 19.37 million tons per annum. Biogas production from biomass could result in conserving 10.38 million tons of nitrogen and replace (save) 13.23 million tons of biomass per annum in Zambia. The saved biomass can be used in the production of biogas and other modern bioenergy types. Biogas production could also result into production of 290 × 103 tons of organic fertilizer per annum as a by-product. Comparing this with the current chemical fertilizer consumption trends, 76% of the chemical fertilizer could be replaced. This would result into saving of forex and avoid emissions from raw material used in the processing of chemical fertilizers. An opportunity cost of approximately US$1 million per day exists if all households would engage in biogas production. There is need to create a comprehensive assessment framework for identifying and assessing environmental benefits arising from biogas implementation. The study closes data gaps that have existed for a long time and will be beneficial to policy makers, academicians and interested parties.