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This paper presents the potential of biogas from anaerobic digestion of vinasse and its impact in different contexts. The use of vinasse biogas (VBG) for power generation is evaluated and the potential of this energy source is compared with fossil oil power plants in terms of energy, costs and greenhouse gases (GHG) emissions in Brazil, suggesting a program where the most expensive oil power plants are replaced by biogas plants with benefits in all aspects. Secondly, the use of vinasse biomethane (VBM) to replace natural gas (NG) in the state of São Paulo is examined, presenting an incentive program that could make this alternative fuel feasible even in smaller scale plants with minimal impact on NG costs in this state, while providing considerable emission reduction. The impact of VBG considering the increase in ethanol production over the next ten years is also evaluated, showing that substantial additional energy can be obtained and larger amounts of fossil fuels can be replaced. By crossing vinasse biogas potential with selected fossil fuels demand, the article brings insights to help the transition to a low-carbon society in a novel approach. The conclusions are that VBG and VBM can provide great benefits, such as USD 1 billion/year cost reductions and 6.7 million tons CO 2e /year emissions avoided by replacing fossil oil by biogas in power generation in Brazil and 3.2 million tons CO 2e /year avoided with biomethane replacing natural gas in the state of São Paulo, which, with specific programs and policies, could be achieved. • Vinasse biogas could replace fossil oil and natural gas in Brazil. • Electricity from vinasse biogas avoid GHG emissions at lower costs than oil plants. • Vinasse biomethane can replace natural gas in São Paulo with minimal cost increase. • Vinasse biogas can substitute more fossil fuels with increased ethanol production. [ABSTRACT FROM AUTHOR]

There have been many efforts to improve sugarcane cultivation and conversion technologies in the ethanol industry. In this study, an economic assessment and greenhouse gas (GHG) emissions analysis are performed on ethanol produced conventionally from sugarcane sugar and on an emerging process where the sugarcane bagasse is additionally used to produce ethanol. The combined conventional plus lignocellulosic ethanol pathway is found to be less economically favorable than the conventional ethanol pathway unless a series of technical challenges associated with cost reductions in lignocellulosic ethanol production are overcome, reaching a production cost at 0.31 $/L. This is expected to be achieved in a prospective 2020 scenario. GHG emissions savings against gasoline for both the conventional ethanol and the conventional plus lignocellulosic ethanol pathways are confirmed and found to increase with technological developments projected to occur over time. However, the absolute numbers are highly sensitive to the way of claiming credits from surplus electricity co-generated in the mill. These are 86%, 110% and 150% for the conventional ethanol in the 2020 scenario when the surplus electricity is assumed to replace the average electricity, the ‘combined-sources’ based electricity and the marginal electricity, respectively. For the conventional plus lignocellulosic ethanol pathway, they are 80%, 85% and 95% respectively in the 2020 scenario. Finally, a series of sensitivity analyses found the comparison in the GHG emissions between the two production pathways is not sensitive to changes in the sugarcane yield or the emissions factor for the enzymes used in the lignocellulosic ethanol process. However, the plant size is an influential factor on both the ethanol production cost (a lowest MESP of 0.26 $/L at the scale of 4 MM tonne cane/yr) and the GHG emission factors, partially because of the important role that transport of feedstock biomass (sugarcane and trash) plays in both elements. [ABSTRACT FROM AUTHOR]