Biogas as an alternative to fuelwood for a household in Uleppi sub-county in Uganda

Abstract

Over 93% of Uganda’s population relys on wood fuel in form of either charcoal or fuelwood for cooking.  Uleppi sub-county in Arua district is a typical example of such areas in Uganda where households entirely use fuelwood to meet their energy demand for cooking.  The use of fuelwood is however associated with the use of inefficient stoves that accelerate deforestation thus increasing carbon dioxide (CO₂) emissions.  The use of fuelwood is also associated with a smoky environment that has adverse health impacts on women and children who spend long hours in the kitchen.  In addition, women and children spend long hours gathering fuelwood which significantly reduces farm productivity.  This project was therefore aimed at design and construction of a biogas plant ideal for a household in Uleppi sub-county as an alternative to fuel wood.  The research involved sizing of the floating drum biogas digester and gasholder, economic analysis as well as estimating CO₂ emission reduction.  For a household with an average of three heads of cattle managed in a free range system, the biogas digester and gasholder were sized as 1.4 m³ and 0.29 m³ respectively with 0.48 m³ of biogas produced per day.  At this capacity, it was found that biogas utilization can reduce individual household consumption of wood fuel by 66.32% for a household size of five persons.  The carbon emission reduction for all households was estimated at 432 tons of CO₂ per year.  The benefit-cost ratio was found to be 3.26, hence worthy to invest in the biogas technology.  The capital recovery period for 459 USD of the biogas plant installation with an economic life of 15 years at 23 % interest rate was found to be two years.

Keywords: biogas, carbon dioxide, emissions, fuelwood, floating drum, Uganda