Vinasse biogas for energy generation in Brazil: An assessment of economic feasibility, energy potential and avoided CO2 emissions

Abstract

Energy recovery from waste is one of the strategies that can assist the expansion of renewable energy in Brazil. Among the various types of waste, vinasse, which is a residue that contains a high organic load, originates from the sugarcane industry, which is a very important industry for the Brazilian economy. Due to high levels of sugarcane harvesting in the country and the production of large amounts of ethanol, vinasse is produced at high levels in Brazil. In this context, this paper presents an energy analysis of the avoided carbon dioxide emissions and economic viability associated with the combustion of biogas produced by the anaerobic digestion of the vinasse that results from the use of sugar cane planted in Brazil. Based on the literature review, data related to the process of biogas production from anaerobic digestion of the vinasse were collected and used for the calculation of the energy potential associated. The results show that to achieve economic viability for the use of this waste for energy, the following plantation areas would be required, considering their processed sugarcane equivalents: 14,580 ha (if considering the processing of sugarcane in attached plants), and 6000 ha (if considering the processing of sugarcane in autonomous plants). The total energy potential of this use may reach 3.26 TWhe/y, which represents 0.52% of all domestic energy consumption in 2014. The potential to avoid emissions from the same use could reach 1.9 Mt CO2/y, which is approximately 2.1% of the emissions for the whole industry in Brazil in 2014. These results demonstrate the environmental and energy benefits that can be obtained via power generation from biogas produced by the anaerobic digestion of vinasse and highlight the need to include the use of such residue for energy in expansion plans for the Brazilian energy matrix.