How to evaluate raw material vulnerability - An overview

Companies, economies and technologies are vulnerable to supply disruptions or price peaks of specific raw materials. Multiple research groups worldwide have proposed methodologies for determining the criticality of raw materials, including assessments on the vulnerability to supply restrictions. These raw material vulnerability assessments use manifold indicators but are not consistent concerning their selection, calculation, interpretation and weighting. Their indicators estimate a raw material’s economic importance or its significance for a strategic goal, or they inform regarding the impact of supply disruptions. Here, we provide an overview of 18 vulnerability assessments in 16 recent criticality studies. Our results reveal 18 different vulnerability indicators, among which a set of six indicators is frequently used and therefore might be recommended for decision makers. The range of possible vulnerability assessment results is exemplified by evaluations of the transition metal copper and the rare earth neodymium. Our overview can serve as a starting point for future raw material criticality assessments concerning the selection of vulnerability indicators and appropriate calculation and weighting methods.

Related papers:

title: Methodology of metal criticality determination.
abstract: A comprehensive methodology has been created to quantify the degree of criticality of the metals of the periodic table. In this paper, we present and discuss the methodology, which is comprised of three dimensions: supply risk, environmental implications, and vulnerability to supply restriction. Supply risk differs with the time scale (medium or long), and at its more complex involves several components, themselves composed of a number of distinct indicators drawn from readily available peer-reviewed indexes and public information. Vulnerability to supply restriction differs with the organizational level (i.e., global, national, and corporate). The criticality methodology, an enhancement of a United States National Research Council template, is designed to help corporate, national, and global stakeholders conduct risk evaluation and to inform resource utilization and strategic decision-making. Although we believe our methodological choices lead to the most robust results, the framework has been constructed to permit flexibility by the user. Specific indicators can be deleted or added as desired and weighted as the user deems appropriate. The value of each indicator will evolve over time, and our future research will focus on this evolution. The methodology has proven to be sufficiently robust as to make it applicable across the entire spectrum of metals and organizational levels and provides a structural approach that reflects the multifaceted factors influencing the availability of metals in the 21st century.

title: Raw Material Criticality in the Context of Classical Risk Assessment
abstract: The rapid economic development of emerging countries in combination with an accelerating spread of new technologies has led to a strongly increasing demand for industrial metals and minerals regarding both the total material requirement and the diversity of elements used for the production of specific high-tech applications. Several minor metal markets which are often characterized by high market concentrations of raw material production at the country and the company level have shown high turbulences since the beginning of the 21st century. This has led to growing concerns about the security of raw material supply, particularly in established western economies. As a result, numerous studies on supply risks and raw material criticality for different countries and regions were carried out recently. In this paper, we discuss the methodology of raw material criticality assessment within a criticality matrix which is a modification of a classical risk matrix. Therefore, we first provide an overview of the approaches and results of major studies quantifying raw material criticality by means of a criticality matrix. By applying a uniform scaling to the matrices of different recent studies, a direct comparison of results and data interpretation was enabled. As shown in this paper, the close relation between the criticality matrix and classical risk analysis within a risk matrix was overlooked in most studies which may lead to misunderstanding and misinterpretation of the results. We posit that the interpretation of the coordinates within the criticality matrix and the thresholds separating critical and non-critical raw materials need to be revised by means of general risk definitions.

title: Six Years of Criticality Assessments: What Have We Learned So Far?
abstract: The “criticality” of the various elements used in modern technologies is a topic of increasing interest, with groups from governments, consultancies, and academic institutions developing a variety of methodologies and using them to make assessments. Other groups from similar organizations are studying the methodologies that generate these assessments. Here, we analyze the different types of studies, review issues of methodology, and comment on features of nine different studies published between 2008 and mid‐2014. From these studies, we derive lists of problematic, debatable, and desirable aspects of criticality studies. We emphasize that the criticality of an element can vary depending on the target organization and that, because criticality is a dynamic state, it must be periodically re‐evaluated. There is substantial value to be derived if a more uniform methodology could be developed. We discuss how a harmonized methodological framework might be achieved and what its benefits could be. Putting into place such a structure for collaborative and publicly available criticality determinations would be very likely to better serve the present and future needs of corporations and governments than is the case at present, where different methodologies generate different results.

title: Assessing the national economic importance of metals: An Input–Output approach to the case of copper in France
abstract: The national economic importance of a metal is usually considered as one of the indicators of this metal׳s vulnerability to supply restrictions at a national level. In a context of developed economies in which service activities stand for the largest share of GDP, this study proposes to account for the interplays between economic activities, including service activities, in the assessment of a metal׳s national economic importance. An index for qualifying a metal׳s relative economic importance is defined in such a way as to highlight to what extent the value added domestically induced by each domestic final use is dependent on this metal. The methodology, based on hybrid monetary physical Input–Output Analysis, is described and applied to the case of copper in France for the year 2008. “Constructions and construction works” represent the largest contribution to the index of copper׳s national economic importance. The hidden copper consumptions induced by the final uses of certain services (e.g. “public administration and defense services”) imply that these are more critical in terms of supply restrictions than some other copper-containing products (e.g. “computer, electronic and optical products”). The limitations and corresponding necessary future developments of such an approach are finally discussed.

title: Criticality Assessment of Metals for Japan's Resource Strategy
abstract: Criticality assessment of metals has been developed to analyze a country’s supply risk and vulnerability to supply restriction. This study presents Japan’s criticality of 22 metals during 2012. Whereas a past assessment focused only on minor metals, evaluation targets here included both common and minor metals. In addition, a new analytic method included mineral interest sufficiency as a criticality component. The evaluation framework developed in this study included 13 criticality components within five risk categories: supply risk, price risk, demand risk, recycling restriction, and potential risk. Weighting factors were used to aggregate components into a single score. This framework reflects a recent government announcement about Japan’s resource strategy. High criticality was found for neodymium, dysprosium, and indium due to a recent increase in demand. Niobium also had high criticality due to production concentration in Brazil. There were few differences in the aggregated criticality scores between the other minor metals and common metals. For minor metals, aggregated criticality was mainly increased by production concentration and recycling difficulty. For common metals, aggregated criticality was increased by short depletion time and growth in global mine production. Compared with a previous study, in 2012 the criticality of tungsten and tantalum were lower due to reduced domestic demand. The analytic methods and results presented in this study will be useful in developing Japan’s resource strategy. ]

title: Identifying critical materials for photovoltaics in the US: A multi-metric approach
abstract: There are increasing concerns that physical material constraints threaten energy security and the growth of emerging technologies. Traditional approaches to quantify material criticality utilize single-score metrics which are narrowly focused on physical scarcity and often lead to command-and-control policies. However, a broader definition of criticality that goes beyond physical scarcity to include sustainability metrics e.g. embodied energy, political instability, economic value can provide policymakers with a more comprehensive perspective of the complex and highly interconnected relationships between indicators. We use the case of solar photovoltaic materials to demonstrate the challenges and opportunities in critical materials policy and indicator choices. For silicon-based and thin-film photovoltaics in particular, Ge, Pt, As, In, Sn and Ag were found to be the most critical relative to the 17 materials studied. Multi-metric analysis for these materials reveals tradeoffs that suggest friction between sustainable economics, political stability of supply, and environmental quality objectives.

title: Assessing the dynamic material criticality of infrastructure transitions: A case of low carbon electricity
abstract: Decarbonisation of existing infrastructure systems requires a dynamic roll-out of technology at an unprecedented scale. The potential disruption in supply of critical materials could endanger such a transition to low-carbon infrastructure and, by extension, compromise energy security more broadly because low carbon technologies are reliant on these materials in a way that fossil-fuelled energy infrastructure is not. Criticality is currently defined as the combination of the potential for supply disruption and the exposure of a system of interest to that disruption. We build on this definition and develop a dynamic approach to quantifying criticality, which monitors the change in criticality during the transition towards a low-carbon infrastructure goal. This allows us to assess the relative risk of different technology pathways to reach a particular goal and reduce the probability of being ‘locked in’ to currently attractive but potentially future-critical technologies. To demonstrate, we apply our method to criticality of the proposed UK electricity system transition, with a focus on neodymium. We anticipate that the supply disruption potential of neodymium will decrease by almost 30% by 2050; however, our results show the criticality of low carbon electricity production increases ninefold over this period, as a result of increasing exposure to neodymium-reliant technologies.

title: Criticality of metals for electrochemical energy storage systems. Development towards a technology specific indicator
abstract: The technology of electrochemical energy storage (EES) is supposed to play a key role in the near future for mobility systems characterized by electric vehicles as well as for stationary applications providing energy supply as they represent the interface between transport and energy networks. The performance of EES systems is closely linked to the applied battery materials which contain metals often considered critical. For determining criticality of metals different approaches have been used which however evaluate such materials for the economy as a whole. What has been missing up till now is the examination of critical raw materials for individual technologies.Therefore it is intended to develop a technology specific criticality indicator for battery materials.The focus of this paper is developing a method to indicate the significance of raw materials for electrochemical active materials used by lithium-ion batteries (LIB) which are currently very promising EES for mobile and stationary applications. In order to implement this at first the following three aspects were analyzed and put in relation to each other: importance of electrode materials, amount of metal in the active material and exploitable metal reserves. The combination of these factors resulted in a relevance index (RI) which allows determining the relevance of raw materials in different types of LIBs. Based on this index the development of a technology specific criticality indicator has to integrate further aspects being the focus of future work.

title: The criticality of four nuclear energy metals
abstract: Concerns about the future balance between the supply and demand of metals have inspired research to define and assess metal criticality. Here we apply a comprehensive criticality methodology to four metals with uses in nuclear energy: zirconium (Zr), hafnium (Hf), thorium (Th), and uranium (U). 2008 criticality assessments for these metals were made on the national level for the United States and on the global level. The results and uncertainty estimates in three-dimensional “criticality space” are comprised of supply risk (SR), vulnerability to supply restriction (VSR), and environmental implications (EI) axes. The SR score is the highest for zirconium over both the medium term (i.e., 5–10 years) and the long term (i.e., a few decades). The cradle-to-gate EI score is highest for uranium, followed by hafnium and then thorium, with impacts due to a combination of on-site emissions and upstream burdens from the use of energy and materials during mineral processing and refining. Uranium has the highest VSR score at the national level, and the second highest at the global level. Zirconium is the most vulnerable at the global level. In general, SR for the four metals are reasonably high for the United States and more moderate for the planet, while EI and VSR scores are low to moderate. Overall, the criticality of the metals analyzed appears not to be of high concern, either nationally or globally.

title: Criticality of the Geological Zinc, Tin, and Lead Family
abstract: Concerns about the future availability and continuity of metal supplies have triggered research efforts to define and assess metal criticality. In this study, we apply a comprehensive methodology to the elements of the geological zinc, tin, and lead family: zinc (Zn); germanium (Ge); cadmium (Cd); indium (In); tin (Sn); and lead (Pb). Zn, Sn, and Pb have played important roles in various technological sectors for centuries, whereas Ge, Cd, and In are by‐product metals that are increasingly utilized in emerging and strategic technologies. Criticality assessments are made on national (i.e., the United States) and global levels for 2008. The results are presented with uncertainty estimates in three‐dimensional “criticality space,” comprised of supply risk (SR), environmental implications, and vulnerability to supply restriction (VSR) axes. SR is the highest for In for both the medium (i.e., five to ten years) and long term (i.e., a few decades). Pb and Zn have the lowest SR for the medium term and Pb the lowest SR for the long term. In and Ge production have the highest environmental burdens, mainly as a result of emissions from Zn smelting and subsequent metals purification and recovery from Zn leaching residues. VSR is highest for Pb at the global and national levels.

title: Criticality of the Rare Earth Elements
abstract: Recent constraints on supplies of the rare earth elements (REEs) have led to concerns about their long‐term availability as well as the consequences that shortages would pose for modern technology. To assess this situation, we apply a comprehensive “criticality” methodology to the REE: lanthanum (La); cerium (Ce); praseodymium (Pr); neodymium (Nd); samarium (Sm); europium (Eu); gadolinium (Gd); terbium (Tb); dysprosium (Dy); holmium (Ho); erbium (Er); thulium (Tm); ytterbium (Yb); lutetium (Lu); and yttrium (Y). Assessments are made on national (U.S. and China) and global levels for the year 2008. Evaluations of each indicator are presented and the results plotted in “criticality space” on a 0 to 100 scale. Over the medium term (5 to 10 years), supply risk (SR) for all REEs is moderate with minimal variation (62.8 to 65.1). Over the long term (10 to 100 years), SR is low (42.1 to 49.2). Environmental implications scores, reflecting the economic allocation of environmental burdens, range from 4.2 for La to 34.4 for Lu. Eu, Er, and Dy have the highest vulnerability to supply restriction (VSR) at the global level (50.6, 49.2, and 47.4, respectively), whereas Sm has the lowest (15.1). This is mainly a reflection of their substitution potential. Similarly, at the national level for the United States and China, Eu and Sm have the highest and lowest VSR scores, respectively, although there are notable differences in scores among the REEs and between countries. Although China's export restrictions render REE supplies inadequate to meet demand at present, our analysis indicates a lower criticality for REEs over the longer term than for a number of other industrially used metals.

title: Criticality of the geological copper family.
abstract: Because modern technology depends on reliable supplies of a wide variety of materials, and because of increasing concern about those supplies, a comprehensive methodology has been created to quantify the degree of criticality of the metals of the periodic table. In this paper, we apply this methodology to the elements of the geological copper family: Cu, As, Se, Ag, Te, and Au. These elements are technologically important, but show a substantial variation in different factors relating to their supply risk, vulnerability to supply restriction, and environmental implications. Assessments are made on corporate, national, and global levels for year 2008. Evaluations of each of the multiple indicators are presented and the results plotted in "criticality space", together with Monte Carlo simulation-derived "uncertainty cloud" estimates for each of the aggregated evaluations. For supply risk over both the medium term and long term, As is the highest risk of the six metals, with Se and Ag nearly as high. Gold has the most severe environmental implications ranking. Vulnerability to supply restriction (VSR) at the corporate level for an invented solar cell manufacturing firm shows Se, Te, and Cu as approximately equal, Cu has the highest VSR at the national level, and Cu and Au have the highest VSRs at the global level. Criticality vector magnitudes are greatest at the global level for As (and then Au and Ag) and at the national level for As and Au; at the corporate level, Se is highest with Te and Cu lower. An extension of this work, now in progress, will provide criticality estimates for several different development scenarios for the period 2010-2050.

title: Criticality of iron and its principal alloying elements.
abstract: Because modern technology depends on reliable supplies of a wide variety of materials and because of increasing concern about those supplies, a comprehensive methodology was created to quantify the degree of criticality of the metals of the periodic table. In this paper, we apply this methodology to iron and several of its main alloying elements (i.e., vanadium, chromium, manganese, and niobium). These elements represent the basic metals of any industrial society and are vital for national security and economic well-being. Assessments relating to the dimensions of criticality - supply risk, vulnerability to supply restriction, and environmental implications - for 2008 are made on the global level and for the United States. Evaluations of each of the multiple indicators are presented, with aggregate results plotted in "criticality space", together with Monte Carlo simulation-derived "uncertainty cloud" estimates. Iron has the lowest supply risk, primarily because of its widespread geological occurrence. Vanadium displays the highest cradle-to-gate environmental implications, followed by niobium, chromium, manganese, and iron. Chromium and manganese, both essential in steel making, display the highest vulnerability to supply restriction, largely because substitution or substitution at equal performance is not possible for all end-uses. From a comprehensive perspective, we regard the overall criticality as low for iron and modest for the alloying elements we evaluated.

title: Criticality of Seven Specialty Metals
abstract: Evaluating metal criticality is a topic that addresses future metals supply and that has inspired research in corporations, academic institutions, and governments. In this article, we apply a comprehensive criticality methodology to seven specialty metals - scandium (Sc), strontium (Sr), antimony (Sb), barium (Ba), mercury (Hg), thallium (Tl), and bismuth (Bi) - at the national and global levels for 2008. The results are presented along with uncertainty estimates in a three‐dimensional “criticality space” comprised of supply risk (SR), vulnerability to supply restriction (VSR), and environmental implications (EI) axes. The SR score is the highest for antimony over the medium term (i.e., 5 to 10 years), followed very closely by bismuth and thallium; for the long term (i.e., a few decades), the highest SR is for thallium, followed very closely by antimony. Strontium and barium, followed very closely by mercury, have the lowest SR over the medium term, and mercury has the lowest SR over the long term. Mercury has the highest EI score. For VSR, thallium is the most vulnerable at both the national level (for the United States) and global level, followed by strontium at both levels. In general, specialty metals are found to possess a unique mix of sparse data, toxicity concerns (in some cases), and inadequate or nonexistent substitutes for a number of specialized uses, a situation that would seem to demand increased effort in acquiring the information needed to characterize specialty metal criticality with more rigor and transparency than is currently possible.

title: Reviewing resource criticality assessment from a dynamic and technology specific perspective: using the case of direct-drive wind turbines
abstract: The recent debate on potential resource constraints for the broad scale implementation of clean energy technologies in future has led to wider concern across the board. This concern, among others, lies behind growing research in the field of so-called resource criticality. This study is a review of existing resource criticality assessment methodologies. It characterizes and analyses existing methods and identifies aspects of concern for the ability of assessment methods to provide proper guidance for strategy making in the field of energy system development. The validity of the identified concerns is, further, demonstrated by applying a case study of resource criticality assessment of the direct-drive wind turbines technology. Two key concerns are identified. The first is the need for a dynamic perspective on the supply risk dimension. This study reveals that the geological reserve estimates and geographical location of supply change significantly over time, implying that the static supply risk assessment provided by many methods gives misleading guidance. The second concern is the ability of methods to properly account for the vulnerability of the studied system to a supply disruption of the resource in question. Through the case study, the options for resource substitution are elaborated for wind turbines by applying a holistic design approach looking at all levels of design substitutions from the level of materials and components to subassemblies and whole-product concepts. This approach reveals that the dependence of substances like neodymium and dysprosium is not strong, and that they are not essential to the wider implementation of direct-drive wind turbines in general. This technology specific and product design based approach is new, and questions the ability of existing methods to properly address the impact that the risk of supply disruption of a given resource really has on the technological and economic development of a system or technology under study.

title: Metal production requirements for rapid photovoltaics deployment
abstract: As global photovoltaics (PV) deployment grows, the required input materials need to be supplied at an increasing rate. In this paper, we quantify the effect of PV deployment levels on the scale of metal production. For example, we find that if cadmium telluride {copper indium gallium diselenide} PV accounts for more than 3% {10%} of electricity generation by 2030, the required growth rates for the production of indium and tellurium would exceed historically-observed production growth rates for a large set of metals. In contrast, even if crystalline silicon PV supplies all electricity in 2030, the required silicon production growth rate would fall within the historical range. More generally, this paper highlights possible constraints to the rate of scaling up of metal production for some PV technologies, and outlines an approach to assess projected metal growth requirements against an ensemble of past growth rates from across the metal production sector. The framework developed in this paper may be useful for evaluating the scalability of a wide range of materials and devices, to inform technology development in the laboratory, as well as public and private research investment.