Closed‐Loop Supply Chains for Photovoltaic Panels: A Case‐Based Approach

Photovoltaic (PV) waste is expected to significantly increase. However, legislation on producer responsibility for the collection and recovery of PV panels is limited to the European Union (EU) Waste Electrical and Electronic Equipment Directive Recast, which lays down design, collection, and recovery measures. Academic knowledge of closed‐loop supply chains (CLSCs) for PV panels is scarce. We analyze the supply chain using multiple cases involving the main stakeholders in the design, production, collection, and recovery of PV panels. Our article answers two research questions: How does the PV supply chain operate, and what are critical factors affecting the reverse supply chain management of used panels? Our research seeks to fill the gap in the CLSC literature on PV panels, as well as to identify barriers and enablers for PV panel design, collection, and recycling.     

Raw material criticality assessment as a complement to environmental life cycle assessment: Examining methods for product‐level supply risk assessment

The diversity of raw materials used in modern products, compounded by the risk of supply disruptions—due to uneven geological distribution of resources, along with socioeconomic factors like production concentration and political (in)stability of raw material producing countries—has drawn attention to the subject of raw material “criticality.” In this article, we review the state of the art regarding the integration of criticality assessment, herein termed “product‐level supply risk assessment,” as a complement to environmental life cycle assessment. We describe and compare three methods explicitly developed for this purpose—Geopolitical Supply Risk (GeoPolRisk), Economic Scarcity Potential (ESP), and the Integrated Method to Assess Resource Efficiency (ESSENZ)—based on a set of criteria including considerations of data sources, uncertainties, and other contentious methodological aspects. We test the methods on a case study of a European‐manufactured electric vehicle, and conclude with guidance for appropriate application and interpretation, along with opportunities for further methodological development. Although the GeoPolRisk, ESP, and ESSENZ methods have several limitations, they can be useful for preliminary assessments of the potential impacts of raw material supply risks on a product system (i.e., “outside‐in” impacts) alongside the impacts of a product system on the environment (i.e., “inside‐out” impacts). Care is needed to not overlook critical raw materials used in small amounts but nonetheless important to product functionality. Further methodological development could address regional and firm‐level supply risks, multiple supply‐chain stages, and material recycling, while improving coverage of supply risk characterization factors.     

Thermodynamic rarity of electrical and electronic waste: Assessment and policy implications for critical materials

The strategic relevance of extracting raw materials from waste from electrical and electronic equipment (WEEE) in the EU is increasing due to value chain risks caused by geopolitical instability, accessibility of specific minerals, and decreasing reserves due to growing extraction rates. This article examines the quantities of so-called critical raw materials (CRMs) originating within WEEE streams from a depletion perspective. Presently, current recycling targets are based solely on mass collection and recycling rates. We examine the potential limitations of this approach using an exergy-based indicator named thermodynamic rarity. This indicator represents the exergy costs needed for producing materials from the bare rock to market. The case of Italy is used to explore the application of the indicator at the macro (national) and micro (company) level for the product categories “small electronics” and “screens and monitors.” Our estimations show significant differences between the mass and rarity of materials within Italian WEEE streams. While iron accounts for more than 70% of the weight of the product categories analyzed, it accounts for less than 15% of the rarity. Similarly, several CRMs with a small mass have a higher rarity value, for example, tungsten with less than 0.1% of the mass and over 6% of the rarity. The policy context is reflected upon, where it is argued that thermodynamic rarity can provide novel insights to support end-of-life WEEE decision-making processes, for example, target development and recycling standards setting to help prioritize material monitoring and recovery options.     

High‐Resolution Insight into Materials Criticality: Quantifying Risk for By‐Product Metals from Primary Production

Many advanced energy and environmentally relevant technologies rely on metals that have been identified as critical, or whose availability may be limited. Several of these elements are produced mostly as by‐products of mining other base metals (carriers). This by‐product dependence has been proposed as a significant supply‐risk indicator by the materials criticality community. This article provides new quantitative evidence that, in several cases, by‐product metals’ availability may not be directly limited by carrier supply. We perform an assessment based on characteristics essential to by‐product metals, including physical concentration, market value of metals, and extraction technology efficiency. We analyze 40 carrier/by‐product pairs and identify five ‘high‐by‐product’ pairs. We assess the supply responsiveness of these metals. Our analysis suggests that rather than limited primary production of carrier, lack of incentive for improving recovery efficiency may limit availability of the by‐product. This behavior is found in the zinc‐indium and copper‐selenium systems. For germanium, on the other hand, we instead propose influence from the by‐product market itself leading to price inelasticity of supply. As a complement to other quantitative methods developed for material systems, such as material flow analysis, we provide an essential technoeconomic analysis of the by‐product metals problem by employing cluster analysis and econometric modeling. This approach provides insight into supply‐risk mitigation strategies related to extraction efficiency and supply‐chain structure.     

Complex interactions between cis-regulatory modules in native conformation are critical for Drosophila snail expression

It has been shown in several organisms that multiple cis-regulatory modules (CRMs) of a gene locus can be active concurrently to support similar spatiotemporal expression. To understand the functional importance of such seemingly redundant CRMs, we examined two CRMs from the Drosophila snail gene locus, which are both active in the ventral region of pre-gastrulation embryos. By performing a deletion series in a ～25 kb DNA rescue construct using BAC recombineering and site-directed transgenesis, we demonstrate that the two CRMs are not redundant. The distal CRM is absolutely required for viability, whereas the proximal CRM is required only under extreme conditions such as high temperature. Consistent with their distinct requirements, the CRMs support distinct expression patterns: the proximal CRM exhibits an expanded expression domain relative to endogenous snail, whereas the distal CRM exhibits almost complete overlap with snail except at the anterior-most pole. We further show that the distal CRM normally limits the increased expression domain of the proximal CRM and that the proximal CRM serves as a `damper' for the expression levels driven by the distal CRM. Thus, the two CRMs interact in cis in a non-additive fashion and these interactions may be important for fine-tuning the domains and levels of gene expression.     

Static material flow analysis of neodymium in China

Neodymium is one of the most important enabling materials for next‐generation clean technologies, especially electric vehicles and wind turbines. As the world's largest producer of rare earth minerals, China dominates the global neodymium supply and a considerable amount of primary neodymium resources are from illegal mining. Many studies have been conducted on the material flow of neodymium in different regions, but few studies focus on China. In this study, a static material flow analysis of neodymium is conducted to quantitatively analyze the industrial chain structure of neodymium in China and to calculate the neodymium output from illegal mining. The results quantitatively depict the neodymium material flow of each stage of China's neodymium industrial chain in 2016, which indicates that 12.3–17.0 kt of primary neodymium resources were from illegal mining. On the basis of the results, reasonable conclusions can be drawn that the recycling of neodymium from end‐of‐life products provides an important opportunity to both reduce illegal rare earth mining and cope with increasing neodymium demand.     

Information-Based Manufacturing with the Web

Manufacturing has been evolving over the years as different needs and technologies arise. This paper describes an emerging manufacturing technology driven by information systems, the global network infrastructure, and new business models driven by the availability of real-time information. Information-based manufacturing concerns using the right information to know what products to make, when to make them, and then making them the best possible. This becomes more complicated when a number of products, facilities, markets, and companies are involved. More than just information is needed. Connectivity, ability to coordinate and integrate, and implementation strategy all are important. Information systems provide the infrastructure to carry out these objectives. Because of the need for an effective information infrastructure, the Internet has the potential to further enhance information-based manufacturing. Information-based manufacturing can be efficient only when the underlying supply-chain network is run efficiently, for the supply chain provides the infrastructure for directing all the activities from receiving raw materials to the delivery of final products. This paper illustrates how the Web technology can help coordinate the supply-chain activities in manufacturing. It also illustrates the relationships between product types, supply-chain structures, information-sharing, coordination, and the Web.