Some strategic raw materials do have an extremely unsecure supply situation. Several working groups around the world have made criticality assessments for metallic raw materials to analyze the driving impact factors for this instability. However, the influences on raw material availability are manifold and therefore criticality assessment methods are very heterogeneous. Here we give an overview about the differences and similarities of supply risk evaluation in 15 criticality assessment methods. We take the example of Indium, which has been rated in 60 % of thesecriticality studies, and show which data base is used for supply risk evaluation. Our results show a lack of consensus about which indicators give reliable information for raw material supply risk and how these indicators should be aggregated. We anticipate our essay to be a starting point for more justified indicator selection and weighting in criticality assessments.

One possibility for electrification of road transport consists of battery electric vehicles in combination with carbon-free sources of electricity. It is highly likely that lithium-ion batteries will provide the basis for this development. In the present paper, we use a recently developed, semi-quantitative assessment scheme to evaluate the relative supply risks associated with the elements used in the functional materials of six different lithium-ion battery types. Eleven different indicators in four supply risk categories are applied to each element; the weighting of the indicators is determined by external experts within the framework of an Analytic Hierarchy Process. The range of supply risk values on the elemental level is distinctly narrower than in our previous work on photovoltaic materials. The highest values are obtained for lithium and cobalt; the lowest for aluminium and titanium. Copper, iron, nickel, carbon (graphite), manganese and phosphorous form the middle group. We then carry out the assessment of the six battery types, to give comparative supply risks at the technology level. For this purpose the elemental supply risk values are aggregated using four different methods. Due to the small spread at the elemental level the supply risk values in all four aggregation methods also lie in a narrow range. Removing lithium, aluminium and phosphorous from the analysis, which are present in all types of battery, improves the situation. For aggregation with the simple arithmetic mean, an uncertainty analysis shows that only lithium-iron phosphate has a measurably lower supply risk compared to the other battery types. For the “cost-share” aggregation using seven elements, lithium cobalt oxide has a substantially higher supply risk than most other types

Purpose Assessing impacts of abiotic resource use has been a topic of persistent debate among life cycle impact assessment (LCIA) method developers and a source of confusion for life cycle assessment (LCA) practitioners considering the different interpretations of the safeguard subject for mineral resources and the resulting variety of LCIA methods to choose from. Based on the review and assessment of 27 existing LCIA methods, accomplished in the first part of this paper series (Sonderegger et al. 2020), this paper provides recommendations regarding the application-dependent use of existing methods and areas for future method development. Method Within the “global guidance for LCIA indicators and methods” project of the Life Cycle Initiative hosted by UN Environment, 62 members of the “task force mineral resources” representing different stakeholders discussed the strengths and limitations of existing LCIA methods and developed initial conclusions. These were used by a subgroup of eight members at the Pellston Workshop® held in Valencia, Spain, to derive recommendations on the application-dependent use and future development of impact assessment methods. Results and discussion First, the safeguard subject for mineral resources within the area of protection (AoP) natural resources was defined. Subsequently, seven key questions regarding the consequences of mineral resource use were formulated, grouped into “inside-out” related questions (i.e., current resource use leading to changes in opportunities for future users to use resources) and “outside-in” related questions (i.e., potential restrictions of resource availability for current resource users). Existing LCIA methods were assigned to these questions, and seven methods (ADPultimate reserves, SOPURR, LIME2endpoint, CEENE, ADPeconomic reserves, ESSENZ, and GeoPolRisk) are recommended for use in current LCA studies at different levels of recommendation. All 27 identified LCIA methods were tested on an LCA case study of an electric vehicle, and yielded divergent results due to their modeling of impact mechanisms that address different questions related to mineral resource use. Besides method-specific recommendations, we recommend that all methods increase the number of minerals covered, regularly update their characterization factors, and consider the inclusion of secondary resources and anthropogenic stocks. Furthermore, the concept of dissipative resource use should be defined and integrated in future method developments. Conclusion In an international consensus-finding process, the current challenges of assessing impacts of resource use in LCA have been addressed by defining the safeguard subject for mineral resources, formulating key questions related to this safeguard subject, recommending existing LCIA methods in relation to these questions, and highlighting areas for future method development.

Purpose The safeguard subject of the Area of Protection "natural Resources," particularly regarding mineral resources, has long been debated. Consequently, a variety of life cycle impact assessment methods based on different concepts are available. The Life Cycle Initiative, hosted by the UN Environment, established an expert task force on "Mineral Resources" to review existing methods (this article) and provide guidance for application-dependent use of the methods and recommendations for further methodological development (Berger et al. in Int J Life Cycle Assess, 2020). Methods Starting in 2017, the task force developed a white paper, which served as its main input to a SETAC Pellston Workshop® in June 2018, in which a sub-group of the task force members developed recommendations for assessing impacts of mineral resource use in LCA. This article, based mainly on the white paper and pre-workshop discussions, presents a thorough review of 27 different life cycle impact assessment methods for mineral resource use in the "natural resources" area of protection. The methods are categorized according to their basic impact mechanisms, described and compared, and assessed against a comprehensive set of criteria.

There is a growing concern over the security and sustainable supply of raw material among businesses and governments of developed, material-intensive countries. This has led to the development of a systematic analysis of risk incorporated with raw materials usage, often referred as criticality assessment. In principle, this concept is based on the material flow approach. The potential role of life cycle assessment (LCA) to integrate resource criticality through broadening its scope into the life cycle sustainability assessment (LCSA) framework has been discussed within the LCA communities for some time. In this article, we aim at answering the question of how to proceed toward integration of the geopolitical aspect of resource criticality into the LCSA framework. The article focuses on the assessment of the geopolitical supply risk of 14 resources imported to the seven major advanced economies and the five most relevant emerging countries. Unlike a few previous studies, we propose a new method of calculation for the geopolitical supply risk, which is differentiated by countries based on the import patterns instead of a global production distribution. Our results suggest that rare earth elements, tungsten, antimony, and beryllium generally pose high geopolitical supply risk. Results from the Monte Carlo simulation allow consideration of data uncertainties for result interpretation. Issues concerning the consideration of the full supply chain are exemplarily discussed for cobalt. Our research broadens the scope of LCA from only environmental performance to a resource supply-risk assessment tool that includes accessibility owing to political instability and market concentration under the LCSA framework. Keywords:criticality assessment geopolitical supply risk industrial ecology life cycle assessment life cycle sustainability assessment resources

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Highlights • This article proposes a characterization model for Geopolitical Supply Risk. • The characterization model is based on a socioeconomic cause-effect mechanism. • Supply risk is the multiple of probability and vulnerability. • Two embodiments of the characterization model are presented. • The methods are applied to conventional and electric vehicles.

As a result of the global warming potential of fossil fuels there has been a rapid growth in the installation of photovoltaic generating capacity in the last decade. While this market is dominated by crystalline silicon, thin-film photovoltaics are still expected to make a substantial contribution to global electricity supply in future, due both to lower production costs and to recent increases in conversion efficiency. At present, cadmium telluride (CdTe) and copper-indium-gallium diselenide (CuIn_xGa_1−xSe₂) seem to be the most promising materials and currently have a share of ≈9% of the photovoltaic market. An expected stronger market penetration by these thin-film technologies raises the question as to the supply risks associated with the constituent elements. Against this background, we report here a semi-quantitative, relative assessment of mid- to long-term supply risk associated with the elements Cd, Te, Cu, In, Ga, Se and Mo. In this approach, the supply risk is measured using 11 indicators in the four categories “Risk of Supply Reduction”, “Risk of Demand Increase”, “Concentration Risk” and “Political Risk”. In a second step, the single indicator values, which are derived from publicly accessible databases, are weighted relative to each other specifically for the case of thin film photovoltaics. For this purpose, a survey among colleagues and an Analytic Hierarchy Process (AHP) approach are used, in order to obtain a relative, element-specific value for the supply risk. The aggregation of these elemental values (based on mass share, cost share, etc.) gives an overall value for each material. Both elemental and “technology material” supply risk scores are subject to an uncertainty analysis using Monte Carlo simulation. CdTe shows slightly lower supply risk values for all aggregation options