Abstract
This study reviewed and assessed the economic feasibility and environmental sustainability of biogas use as a source of energy for rural communities in Zimbabwe. Literature including published literature on the production of biogas from cow dung and national livestock assessment were reviewed. The average annual cattle population is at 5 million producing and an average of 8 cattle per household. The biogas digesters sizes of between 4-13 m 3 are suitable for household energy supply, installed at a total cost between USD 900 and USD 1800. The major available feedstock amongst rural communities is cow dung with a biogas yield estimated at 0,04m3 per kg giving a gas production 438,730, 1095 and 1600 m3/year of biogas daily from a substrate feed rate of 30, 50 ,75 and 110 kg for the 4, 6, 9 and 13 m3 respectively. The financial analysis indicated that the LOCE for the digesters are 0.11, 0.07, 0.05 and 0.03 USD/kWh for the 4, 6, 9 and 13 m3 respectively. Above the 4 m3 digester, the biogas digester provides a better cost per kWh against a grid tariff of 0.10 USD/kWh for grid electricity. Total amount of CO2 emissions per annum from the 6 m3 biogas system is1,374.35 í µí±˜í µí±˜í µí±˜í µí±˜í µí±˜í µí±˜í µí±˜í µí±˜2. Study findings indicated biogas as economically feasible and environmentally friendly option for rural energy supply.