Scenario-based Inventory Modelling for Prospective Life Cycle Assessment of Mineral Raw Materials (SIMPL-Minerals)

Purpose The demand for minerals for the energy transition is expected to increase greatly in the coming years, raising concerns about the environmental impacts of their supply. To calculate such future impacts, Prospective Life Cycle Assessment (pLCA) can be applied. However, pLCA studies in the mineral value chain often lack consistency, as they use different parameters for future scenarios. To guide prospective life cycle inventory (LCI) modelling and the consistent use of parameters in the mineral value chain, this study develops a systematic approach. Methods The approach builds on the SIMPL approach for scenario-based inventory modelling for pLCA by adding extensions specific to mineral value chains, resulting in the SIMPL-Minerals (SIMPL-M) approach. These extensions include defining stages and processes of mineral value chains, identifying parameters that connect to these stages, and linking parameters to macro-level factors that influence their future development. The identified parameters were validated through semi-structured interviews with experts. Furthermore, the SIMPL-M approach is demonstrated through a case study on future global nickel sulfate supply for battery production. Results and discussion The SIMPL-M identifies 19 relevant parameters that should be considered in pLCA studies of mineral value chain. These parameters depend on deposit characteristic-, technology-, and geography, and cover both primary and secondary value chains, from ore extraction or waste collection to final raw material product. The parameters are connected to a generic inventory model blueprint that shows to which stage they apply. The parameters are also linked to macro-level factors, enabling consistent scenario generation and coherent assumptions about future development of parameters. Applying the SIMPL-M approach in the nickel sulfate case study shows that including parameters beyond standard LCI background data significantly affects impact assessment results. Conclusion The proposed approach adapts the SIMPL framework to the mineral value chain, resulting in the SIMPL-M approach. SIMPL-M enables practitioners to consistently apply parameters in inventory modelling and to build scenarios based on macro-level factors and their influence on parameter development. This ensures that practitioners comprehensively consider relevant parameters, thus enhancing comparability between pLCA studies and can reduce modelling efforts for practitioners.