An energy source is determined by the net energy it provides and this is due to the energy output and energy input within a system. Biofuels have posed as a prosperous alternative to fossil fuels, but unfortunately, it has been driven mostly by political and economical reasons rather than the physics intrinsic to them. Exportation of biofuels have been announced as “green” solutions without checking if the fuels would arrive to the final user as an energy source or drain. Actually, this is not even known in domestic markets such as Brazil, where ethanol has an outstanding development. This study aims to evaluate the energy expenditures of two case studies within the ethanol production chain – ethanol for road transportation and the baled straw, from mechanical harvesting of sugarcane, for electricity cogeneration. For ethanol road transportation, the two most commons tanker-trucks used were evaluated (30 and 45 m³). For the baled straw, two kinds of bale (prismatic and cylindrical) and three kinds of raking (single, double and triple) were evaluated. Although the largest vehicul for ethanol transportation presented higher gross energy consumption, it expended 12.42% less energy per distance and transported mass (0.626 versus 0.715 MJ km-1 t-1), and had proportionally lower CO2 emission, 12.28% (41.47 versus 47.28 g CO2 km-1 t-1). The baled straw presented 19.72% lower consumption for prismatic bales, due to the truck loading capacities of these bales. The results provide incite on the selection of alternatives operation within energy production systems.
ENERGY EXPENSE BY LOGISTICS WITHIN SUGARCANE’S ENERGY PRODUCTION CHAIN – TWO CASE STUDIES
BERRUTO, Remigio;BUSATO, Patrizia;
2010-01-01
Abstract
An energy source is determined by the net energy it provides and this is due to the energy output and energy input within a system. Biofuels have posed as a prosperous alternative to fossil fuels, but unfortunately, it has been driven mostly by political and economical reasons rather than the physics intrinsic to them. Exportation of biofuels have been announced as “green” solutions without checking if the fuels would arrive to the final user as an energy source or drain. Actually, this is not even known in domestic markets such as Brazil, where ethanol has an outstanding development. This study aims to evaluate the energy expenditures of two case studies within the ethanol production chain – ethanol for road transportation and the baled straw, from mechanical harvesting of sugarcane, for electricity cogeneration. For ethanol road transportation, the two most commons tanker-trucks used were evaluated (30 and 45 m³). For the baled straw, two kinds of bale (prismatic and cylindrical) and three kinds of raking (single, double and triple) were evaluated. Although the largest vehicul for ethanol transportation presented higher gross energy consumption, it expended 12.42% less energy per distance and transported mass (0.626 versus 0.715 MJ km-1 t-1), and had proportionally lower CO2 emission, 12.28% (41.47 versus 47.28 g CO2 km-1 t-1). The baled straw presented 19.72% lower consumption for prismatic bales, due to the truck loading capacities of these bales. The results provide incite on the selection of alternatives operation within energy production systems.
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