Avaliação de impactos ambientais da oferta e demanda de energia para automóveis no Brasil utilizando avaliação do ciclo de vida

Abstract

Electric Vehicles (EVs) are seen as a potential solution for the environmental problems associated with Internal Combustion Engine Vehicles (ICEVs). EVs, on the other hand, also cause environmental impacts throughout their life cycles and increases in the demand for electricity, so that they need to be included in the energy planning. Life Cycle Assessment (LCA) studies carried out to assess the environmental impacts of EVs in other countries, indicated that the electricity source is significant to determine whether these present better results than ICEVs or not. For Brazil, however, results might be different, due to the different electricity mix and to the possibility of ICEVs to use sugarcane ethanol. The main purpose of this study is to analyze how to meet the demand for passenger transport by automobiles in Brazil with a smaller environmental impact, for different impact categories. In order to attain this objective, four steps were executed: (i) to define general data, such as the year of projection; (ii) to identify the automobile fleet and the respective energy demand and fulfillment options; (iii) to perform LCA, per vehicle; and (iv) to assess the environmental impact of the fleet, comparing and selecting options with smaller impact. Two time horizons were considered: 2022 and 2030. The ecoinvent database v.3.01 was used as the Life Cycle Inventory (LCI) data source, with some adaptations for the Brazilian context using literature data. Specifically for the identification of the electricity source, the decisional LCI approach was used, for 2022, while, for 2030, possible marginal/incremental technologies were identified. The Life Cycle Impact Assessment (LCIA) method CML 2000 v.2.05 was used, from which three categories were chosen for 2030 (abiotic resource depletion; climate change; and ozone layer depletion), together with LCI results for land occupation. The single score of the LCIA method EDIP 2003 v.1.04 was used in a sensitivity analysis. These methods are available in SimaPro 8.0.2, used for calculations. The results for 2022 showed that, with battery charge during off-peak hours, the EV is better in some impact categories, while the ICEV is better in others. For 2030, however, an EV market penetration of approximately 35% can significantly reduce the impacts for the three CML categories and for the EDIP single score, albeit causing a significant increase in land occupation. These results, therefore, can be compared with other types of land occupations which aim to reduce environmental impacts. It was concluded that EVs have good environmental impacts reduction potentials, in a way that they could be targeted by public policies that address such impacts. Among the uncertainties of this study are included: the simplified identification of energy sources; the use of average parameters for the transportation sector, in part associated only with new vehicles; the definition of the marginal/incremental technology only for electricity; the fact that other vehicle technologies, such as ICEVs powered by second and third generation ethanol; and the use of present or past LCI data to assess future conditions. These could be dealt with in future studies.