Life Cycle inventory for biomethane as a diesel substitute for the Brazilian ethanol industry - Case study

Abstract

Due to concerns for sustainability in production processes reliable Life-cycle assessment (LCA) methodology is needed. Brazilian sugarcane industry processed 651 Mt of sugarcane in the 2016/2017 harvest producing 38.7 Mt of sugar and 27.3 Mm3 of bioethanol, providing more than half domestic fuel consumption for light vehicles, reducing greenhouse gas emissions significantly. Nevertheless, bioethanol production demands diesel, which leaves to a ratio between fossil fuel input to renewable fuel output of up to 1/10. For this work the generation of biomethane from sugarcane residues as a diesel substitute based on data collected at a sugarcane mill located in Goiás State, Brazil, was simulated with the GaBi-software (Thinkstep, Germany). LCA to improve the sustainability of ethanol production leaves to two alternative scenarios: (i) the substitution of 50% of consumed diesel in dual-fuel diesel engines by biomethane for harvesting and crop transport, and (ii) substituting 100% of non-renewable fuels by biomethane.