Análise comparativa das metodologias de avaliação do ciclo de vida e indicador de circularidade de materiais: estudo aplicado às peças de policarbonato de medidores de energia inteligentes

Abstract

With the emergence of the circular economy, companies are restructuring to make better use materials and avoid the extraction of natural resources. However, there is a need to apply metrics to understand the product's circularity and environmental performance. As metrics for analyzing environmental performance and product circularity, the Life Cycle Assessment (LCA) and Material Circularity Indicator (MCI) stand out, respectively. In this sense, the main goal is to carry out a comparative analysis of ACV and MCI applied to a case study of plastic parts, using virgin Polycarbonate + 10% fiberglass (PCv10FV), to protect smart electricity meters. The base scenario is represented using 100% PCv10FV and destinating 100% plastic parts for recycling after use. The approach considered in the study was cradle to grave, including the stages of production and transport of material, injection and transport of plastic parts, distribution of parts for use, collection after use and treatment at end of life. The results of the LCA showed that the environmental impacts of plastic parts in the baseline scenario are mainly caused by the PCv10FV production stage and that sending the parts for recycling after use reduces about 95% of impacts to human health, 95% to the ecosystem and 96% to the resource category. The MCI results applied to the baseline scenario indicated that the parts are 0.548 circular even using only virgin material, considering that the end-of-life parts are sent for recycling. Based on the results of the baseline scenario, sensitivity analyzes of the LCA and MCI were carried out in relation to the percentage of recycled material in the parts and their final treatment after use (recycling or landfill). The results suggest points of similarity and difference between the methodologies. Both methodologies are sensitive to the use of recycled content, so the higher the percentage of recycled material in plastic parts, the better their environmental performance and the greater the degree of circularity. Regarding the end-of-life treatment, the results show that sending the parts for recycling and avoiding disposal in landfills is the best strategy both for the results of the LCA and for the MCI when only virgin content is used in the production of plastic parts. On the other hand, the methodologies differ in some points such as the amount of data needed, the way to present of results and the level of detail of them. While the LCA is normalized, requires information about the product's life cycle and reveals detailed results about the contribution of each stage of the life cycle in different impact categories, the MCI requires data on the origin of the material used in the parts, useful life, their function and the destination of the material after use, and presents the result in a single value. Finally, given the main similarities and differences of the methodologies, the study corroborates the importance of linking the MCI to the LCA in search of circular and sustainable solutions.