Supply Disruption Probabilities of Renewable Energy Sources and Storage Technologies: Assessment from an Energy System Perspective

Abstract

The energy transition to net zero emissions requires a large-scale installation of renewable energy sources (RES), e.g. wind power plants, and energy storages. State-of-the-art RES and energy storage technologies require various metallic resources: bulk materials such as steel and copper mainly for the peripheries, but also potentially critical metals, e.g. for permanent magnets, PV active layers, and battery cells. Many metals in clean energy technologies are subject to potential geopolitical risks. A method for assessing the Supply Disruption Probability (SDP) of individual materials based on the concentration of supplier countries and their political stability has been developed by the European Commission. However, there is not yet an established method for the aggregation of material-level SDP to product level, although a number of different approaches have been proposed: 1. Mass weighted average of material level SDP 2. Cost weighted average of material level SDP 3. Arithmetic mean of material level SDP 4. Maximum of material level SDP The aim of this study is to compare the above aggregation methods of material-level SDP on the product level for the case of different RES and energy storage systems with respect to technology SDP ranking and the contributions of the constituent materials on the overall product level SDP. Our investigation reveals that the choice of the aggregation method has a decisive influence on the final technology-level criticality in two ways. First, the ranking of the RES and energy storage technologies with respect to their SDP is determined by the aggregation method. Accordingly, the aggregation methods tested here do not provide a uniform picture of which a technology has a particularly high SDP or not. Second, the contribution of the considered materials to the product level SDP changes drastically for different aggregation methods Since it is favorable to install low-criticality technologies on a broad scale, a good knowledge about how to define the product level criticality is crucial, especially when using criticality assessments for recommendations on the future energy system. The results highlight that the choice of method for aggregating criticality values from the raw material level to the product level strongly influences the results. This indicates that there is a need for further research at this point.