Implementation of the crustal scarcity indicator into life cycle assessment software
This report provides a detailed description of how the crustal scarcity indicator (CSI) is implemented into the life cycle assessment (LCA) software OpenLCA. The original characterization factors for the CSI, called crustal scarcity potentials (CSPs), were designed to be paired with life cycle inventory data formulated as the amount (mass) of elements extracted from the crust. However, some inventory data is not formulated in terms of mass of elements extracted. For example, data in the Ecoinvent database – the world’s largest LCA database – can also be expressed in terms of the amount of mineral extracted, the amount of rock extracted, or the amount of ore extracted. In order to implement the CSI into OpenLCA in a way that captures such nonelement flows, we construct five categories of inventory data for material flows extracted from the crust. Type A flows are flows of elements, such as lead or tin, which the original CSPs can be paired with. Type B flows are flows of minerals, such as kieserite or stibnite. Type C flows are flows of rocks and groups of minerals, such as basalt or olivine. Type D flows are ores, like copper ore. Type A flows are paired with the CSPs of the respective element types. However, for type B, C and D flows, new CSPs were calculated based on their respective content of different elements. These new CSPs can be found in Appendix A-D. In addition, type E flows are those that are too vaguely formulated in the Ecoinvent database, for example as general metal or ore, making it impossible to derive CSPs. In the concluding discussion, we show that this implementation gives the CSI a wider coverage of different inventory flows than other existing mineral resource impact assessment methods implemented in different packages for OpenLCA. The implementation might thus be considered a guidance for a more all-encompassing implementation of other mineral resource impact assessment methods as well.