TECHNO-ECONOMIC AND CO2 EMISSIONS OF ELECTRIC ENERGY GENERATION FROM MUNICIPAL SOLID WASTE INCINERATION AND LANDFILL GAS: A CASE STUDY IN A MEDIUM-SIZED CITY IN BRAZIL

Abstract

The generation of municipal solid waste (MSW) is a consequence of daily human activity and is directly linked to population growth and intense industrial activity. In this study the technical, economic and environmental aspects of energy generation from MSW were evaluated, focusing on two main technologies: direct combustion in "waste-to-energy" (WTE) plants and the production of biogas in landfills used to generate power through Internal Combustion Engines (ICE). The results indicated that the WTE plant produces five times greater electricity power than the landfill/ICE system. This was corroborated by the exergy analysis, which showed that the WTE plant presented an average exergy efficiency of 15.39% while the landfill system had a maximum Second Law efficiency of 5.56% over the established 20-year lifespan. However, energy generation via landfill proved to be more economically viable, due to low investment and operation and maintenance costs, which are 20 and 4 times lower, respectively. From environmental viewpoint, the WTE plant contributes less to the impact of global warming (2.02 kg CO2 equivalent/kwh) while landfill system 7.92 kg CO2 equivalent/kWh.