Estimating the life cycle impacts of dissipative flows of metals with MaTrace-dissipation
Main Presenter: Guido Sonnemann
Co-Authors: Christoph Helbig Alexandre Philippe Loubet Andrea Thorenz Axel Tuma
Dissipative flows of metals go against the common goal of a more circular economy by making metals inaccessible for future users. Dissipative losses of metals occur by intention as in-use dissipation and unintentionally through losses at all stages of the anthropogenic cycles. Quantifying dissipative flows of mineral resources and assessing their impacts in Life Cycle Assessment (LCA) has been a challenge brought up by various stakeholders in the LCA community. Because life cycle inventory databases currently provide limited information on dissipation, additional efforts are required. This information will allow evaluating the life cycle impact of dissipative flows more accurately and comprehensively.
We address the lacking dissipation data with the two newly developed Life Cycle Impact Assessment (LCIA) methods, Average Dissipation Rate (ADR) and Lost Potential Service Time (LPST). The ADR distinguishes between the conservation potentials of different metals. In contrast, the LPST provides a socio-economic perspective on the lost service due to dissipation over different time horizons. To estimate midpoint and endpoint Characterization Factors (CFs), we provide MaTrace-dissipation, a dynamic stock-and-flow model for quantifying the remaining in-use stock of a cohort of primary material production. MaTrace-dissipation considers parameters for extraction yield, fabrication yield, in-use dissipation, sector-specific product lifetimes and waste collection, and remelting yields. The endpoint CFs are calculated by implementing the market price of metals. MaTrace-dissipation currently calculates the ADR and LPST of 61 metals. This broad data base allows us to apply the ADR and LPST method
to metal resource flows from 6,000 market data sets as an application study.
Well-conserved metals, including iron and aluminum, have low CFs. Companion- and high-tech metals with poor process yields have high CFs. The results can be compared with established LCIA methods like Abiotic Depletion Potential and ReCiPe 2016. The application study shows that metals with the largest resource flows are expected to have the most impacts with the midpoint ADR and LPST methods, while the share of impacts attributed to metals that are more expensive is larger in the endpoint assessment. The ADR and LPST methods provide information on the global dissipation patterns of metals ready for application to elementary resource flows in current life cycle inventories, providing new, complementary information.