CriticS: a resource criticality characterization method for life cycle assessment considering stakeholders’ perspectives

Purpose
Assessing the supply risk of critical raw materials (CRMs) is crucial for supporting green transition strategies. Combining criticality assessment with life cycle sustainability assessment (LCSA) helps to link business actions to supply risks. However, these assessments are characterized by a variety in context, scope, and stakeholder influence, as well as a lack of method standardization. Currently, no operational quantitative method applied to LCSA includes diverse stakeholder perspectives.

Methods
This study proposes a novel fit-for-purpose criticality assessment methodology leveraging existing criticality values from the study on CRMs from the European Commission (EC) while considering different stakeholder perspectives. In this research, several sets of characterization factors (CFs) are proposed, in which the values for supply risk and economic importance from the EC study on CRMs are combined in different ways, in some cases also with further parameters such as material prices. The methodology, called CriticS, guides stakeholders in defining the goal and scope, choosing sets of CFs, and operationalizing the assessment using a product’s bill of materials (BoM) or its life cycle inventory (LCI). ... mehrSpecific sets of CFs are tested in a proof-of-concept case study of a laptop by using its BoM and LCI.

Results and discussion
Supply risk and economic importance values were used to create 19 different sets of CFs. All sets of CFs of the CriticS are organized in a decision tree framework, helping stakeholders to select the most appropriate set of CFs that meets their needs. The CFs are linked to elementary flows in the ecoinvent® database, creating an operationalized model. The results of the proof-of-concept study highlight the benefits and the challenges in applying the CriticS methodology. These challenges are discussed, and potential solutions are identified.

Conclusions
The results demonstrated the usefulness of the CriticS method with regard to the selection of the set of CFs using the decision tree, taking into account a given stakeholder’s perspective. Future research should focus on refining the CF-elementary flow links, integrating CriticS into LCA software, and interpreting the results of the CriticS method together with those of life cycle sustainability assessment.