Life cycle assessment of second-generation biorefineries based on sugarcane straw and eucalyptus forest residues as feedstocks

Abstract

The transport sector's decarbonization is a commitment made on COP21 in order to mitigate climate change effects and assure energy renewability. Brazil made a step to cope with Paris Agreement with RenovaBio, a public policy to promote advanced biofuels production. RenovaBio acknowledges biofuel producers regarding their products' carbon footprint, within their life cycle. With this, second-generation biofuels can finally be recognized for their potential reduction in GHG emissions. The production of cellulosic ethanol from cheap and largely available lignocellulosic residues is a promising pathway in this direction. Harvest residues, such as sugarcane straw (SS) and eucalyptus forest residues (EFR), are available on field and promote important services while covering the soil. An excessive layer, however, is not desirable, since it may lead to fires and pest proliferation. This way, such biomass can be destined to biorefineries to produce advanced biofuels, power and biochemicals, maximizing its value. Despite biomass being considered a carbon neutral raw material, its products' life cycles are not. The same applies to other impact categories, such as acidification, freshwater eutrophication and human toxicity, with the biorefinery products carrying the environmental burden of the agricultural, transportation and industrial phases. This project, thus, aims to build the Life Cycle Inventories of biorefineries process routes using SS and EFR as feedstock, to assess their potential environmental impacts and net greenhouse gases emissions. The contact with experienced LCA practitioners and bioenergy experts will help to absorb vital information on methodologies, inventories of other biomasses and different process routes. (AU)