Simulation of Electricity Generation from Biogas for Ugandan Rural Community

Abstract

One of Uganda's greatest hindrances to development is lack of access to energy. In rural areas where about 84% of the population lives, access to electricity is less than 2% a situation that lives rural communities to continue depending on biomass based fuels in forms of firewood and charcoal. This paper proposes the utilization of biogas to generate off-grid electricity for the rural community. A simulation of electricity generation from biogas for Ugandan rural community using Aspen HYSYS V8.8 for computational modeling was developed on thermodynamic concepts. Two systems were considered; a gas-turbine (GT) only system and a GT-with steam turbine (ST) in the bottom cycle, based on 71% methane-29% carbon dioxide as inlet biogas composition. The results obtained showed that it is possible to obtain 2.5MW of electricity using a gas turbine (GT) only system and an additional 1MW when a combined cycle system (GT-ST) is considered. An analysis of the exhaust gases showed that there are negligible amounts of gaseous pollutant though not in amounts that could constitute environmental threats when disposed to the atmosphere. In order to meet the system's need, a cattle head count of 13740 is estimated to be maintained for a daily supply of 670 tons of cow manure.