Material Efficiency Strategies Research Articles

Global Freight Transport Emissions Responsibility.

The transportation of freight by land, sea and air underpins the complex network of global trade in physical commodities. Greenhouse gas emissions from freight transportation are a significant component of global emissions and are predicted to grow in coming decades. However, the inclusion of freight transport in emissions accounts and environmental impact studies is often incomplete. Both data availability and difficulties in allocating freight emissions to specific commodity trades contributes to this. In this study, international freight movements by transport mode are estimated from the bottom-up by imputing global freight transport routes. Emissions are estimated from these freight movements and integrated with a global multiregional input-output model. This enables the calculation of carbon footprints that are complete with respect to freight emissions. We estimate that global freight transport emissions contributed 2.8 Gt CO2-equiv in 2012, or about 41% of total transport emissions. In general, freight footprints contribute about 9% to national emissions footprints. While trade in physical commodities (such as construction materials, food and fossil fuels) are associated with the largest embodied freight emissions, services (such as public administration, education and health) also require significant freight transport. Using a consumption-based allocation of freight transport emissions allows the decarbonisation of other sectors to be complementary to the decarbonisation of transport through reduction in demand, for example through material efficiency strategies. To drive decarbonisation in maritime transport it is critical to include bunker emissions in national emissions inventories, thereby completing the system boundary.

Estimating and reducing dissipative losses in thermal spray: A parametrized material flow analysis approach

Thermal spray is a family of surface engineering technologies necessary to meet technical functionalities of components under harsh environmental conditions. Those technologies come at the expense of dissipative losses of coating materials throughout the life cycle of components. Measuring these material losses has so far retained little attention in the field. This research provides a framework to estimate material dissipative losses in surface engineering applications based on specific parameters, mainly deposition efficiencies. We applied material flow analysis to quantify dissipative losses for the main metals used in thermal spray (Cr, Co, Mo, Ni, Si, W, Y and Zr). Results show that the coating process is the most contributing life cycle stage (up to 39% of the losses). Improving the deposition efficiency, recovering the unadhered and stripping the components at their end-of-life are key material efficiency strategies to reduce the material losses (up to 50%).

Spatiotemporal characteristics and driving factor analysis of embodied CO2 emissions in China's building sector

Since the embodied emissions of the building sector play a pivotal role in the total emission profile of developing countries, represented by China, it is crucial to uncover its emission characteristics and the underlying drivers. Most existing studies focus on building operational emissions, and there is a lack of in-depth studies on embodied emissions, especially in spatiotemporal heterogeneity and spatial correlation. Thus, this study calculates embodied emissions of the building sector in China's 29 provinces during 2011–2020 and develops an innovative factor analysis model that integrates the extended STIRPAT model, network analysis, and spatial Durbin model to explore the influence mechanisms of various factors on emissions from local, spillover, overall and temporal perspectives. The empirical results reveal notable spatiotemporal differences and spatial dependence across regions. The area has consistently been the most crucial driver. The building performance demands are increasingly influencing emissions through direct and spillover effects. The slowdown decarbonization of the material industry diminishes its impact. Limited technical improvement and regional shifts of carbon-intensive enterprises have weakened the technological emission reduction effects. Therefore, regulating ineffective construction, discouraging excessive building performance, implementing demand-side material efficiency strategies, bolstering interregional coordination, and developing low-carbon technologies are keys to cutting emissions.

Coordinating energy and material efficiency strategies for decarbonizing China's iron and steel sector

Achieving carbon neutrality in China critically depends on the successful decarbonization of its iron and steel sector. While previous studies have primarily focused on improving technology performance in steel production processes, the potential CO2 reduction through material efficiency strategies for steel demand management remains largely unexplored. To bridge this research gap, this study aims to quantitively assess the co-benefits of CO2 reduction from implementing energy and material efficiency strategies along China's steel flow chain. By integrating dynamic steel flow analysis with a CO2 accounting model, this model traces energy use, material flows, and CO2 emissions along the steel flow chain, then evaluates the CO2 reduction potential of implementing various mitigation strategies by 2060, and finally quantifies the relative contribution of each strategy. The findings indicate that the coordination of energy and material efficiency strategies can reduce CO2 by more than 80% from the business-as-usual level by 2060. In particularly, the strategies of more recycling, longer lifetimes, and energy efficiency improvements are projected to contribute −68%, −43%, and −11% of CO2 reduction, respectively, even amidst an expected +29% rise of CO2 emissions driven by economic growth. The study can provide more promising options for decarbonizing China's iron and steel sector and lays the foundation for future analyses that seek to integrate demand-side material efficiency strategies in China's steel decarbonization modeling.

More intensive use and lifetime extension can enable net-zero emissions in China’s cement cycle

Demand-side material efficiency strategies could play a key role in decarbonizing the cement cycle as conventional supply-side measures leave little room for improvement and emerging technologies are still in their infancy and expensive. This study quantitatively evaluates CO2 reduction opportunities through China’s cement cycle by more intensive use and lifetime extension during 2023–2060. More intensive use and lifetime extension can cumulatively save cement consumption by ∼58 gigatons (Gt) during 2023–2060, resulting in CO2 emission reductions of ∼33.8 Gt without considering supply-side actions and cement carbonation. If supply-side measures and cement carbonation are considered, China’s cement cycle could achieve net-zero CO2 emissions by 2060 or even mid-century. Besides, it is important to assess social implications, opportunities, and challenges of lower per-capita stocks and longer service-life, when we aim to realize these emission reductions. Also, trade-offs between CO2 fluxes should be considered in cement decarbonization road mapping because more intensive use and lifetime extension can lower CO2 uptake by cement carbonation.

Material efficiency strategies across the industrial chain to secure indium availability for global carbon neutrality

A global energy transition toward carbon neutrality system requires increased critical metals, and the availability of critical byproduct metals raises concerns due to their dependence on host metals. To ensure the supply security of critical byproduct metals, material efficiency (ME) strategies are needed. Taking indium as an example, this paper explores the indium availability for global energy transition goals, and then illustrates the effects of ME strategies on securing indium availability throughout the whole industry chain. The system dynamics model serves to understand the joint production mechanism of zinc-indium and the nexus between energy transition and indium demand. Results show that the indium supply shortage for global energy transition could be intensified due to a less zinc-intensive economy. To address this challenge, focusing on indium demand reduction is more effective than emphasizing expanding indium supply for global sustainable development goals and material content reduction is the most promising strategy among the five ME strategies. Whereas, eliminating the concerns of indium availability thoroughly for facilitating a carbon neutrality transition requires coordinated ME strategies both from supply-side and demand-side. Moreover, the proposed analysis framework of ME strategies for securing indium availability for energy transition could also be applied for other byproduct metals.

Review of Urban Building Types and Their Energy Use and Carbon Emissions in Life-Cycle Analyses from Low- and Middle-Income Countries.

Urbanization, slum redevelopment, and population growth will lead to unprecedented levels of residential building construction in "low- and middle-income" (LMI) countries in the coming decades. However, less than 50% of previous residential building life-cycle assessment (LCA) reviews included LMI countries. Moreover, all reviews that included LMI countries only considered formal (cement-concrete) buildings, while more than 800 million people in these countries lived in informal settlements. We analyze LCA literature and define three building types based on durability: formal, semiformal, and informal. These exhaustively represent residential buildings in LMI countries. For each type, we define dominant archetypes from across the world, based on construction materials. To address the data deficiency and lack of transparency in LCA studies, we develop a reproducibility metric for building LCAs. We find that the countries with the most reproducible studies are India, Sri Lanka, Turkey, Mexico, and Brazil. Only 7 out of 54 African countries have reproducible studies focused on either the embodied or use phase. Maintenance, refurbishment, and end-of-life phases are included in hardly any studies in the LMI LCA literature. Lastly, we highlight the necessity for studying current, traditional buildings to provide a benchmark for future studies focusing on energy and material efficiency strategies.

Carbon footprint of low-energy buildings in the United Kingdom: Effects of mitigating technological pathways and decarbonization strategies

There is a limited comprehensive analysis of the effectiveness of adopted carbon mitigation strategies for buildings over their life cycle, that are concerned with temporal perspectives of emissions. Accordingly, this paper explores a life cycle assessment (LCA) to address the concerns regarding mitigating the carbon footprint of a UK timber-frame low-energy dwelling. In particular, it aims to investigate the potential greenhouse gas (GHG) emission reduction in terms of three different heating and ventilation options, and to analyze the influence of decarbonization of electricity production as well as the technological progress of the waste treatment of timber on the building's environmental performance. Thus, the whole life‑carbon of the building case studies was evaluated for a total of eight investigated prospective scenarios, and they were compared to the LCA results of the baseline scenario, where the existing technology and context remained constant over time. Results show that using a compact heat pump would lead to a significant whole life-cycle emission reduction of the dwelling, by 19 %; while GHG emission savings can be reinforced if the assessed systems are employed simultaneously with grid decarbonization, exhibiting a 25 %–60 % reduction compared to the baseline scenario. Moreover, technological changes in the waste treatments of timber products could substantially reduce the buildings' embodied emissions, representing 3 %–23 %. From these emission-saving measures, the contribution of material efficiency strategies to achieve more embodied carbon savings should be highlighted in future construction practices.

Comparison between circularity metrics and LCA: A case study on circular economy strategies

The concept of circular economy consists of a wide range of strategies that aim to reduce the environmental impact of production systems and consumption patterns through increased circularity of resources. Circularity is mostly associated with material efficiency strategies that either close, slow or narrow loops, and a multitude of circularity metrics have been developed to evaluate the efficiency of such strategies. Relatively little effort has been made to quantitatively assess the connection between circularity, material efficiency, and environmental sustainability. More knowledge is required about how material-based circularity metrics can be used to guide practitioners of the circular economy towards strategies that foster environmental sustainability. In this study, a novel structured approach is adopted to perform such a comparison by including closing, slowing, and narrowing strategies on a lawn mowing case. Four circularity metrics that can capture material strategies throughout product value chains (Material Efficiency Metric, Material Circularity Indicator, Circularity Potential Indicator and Circular Economy Indicator Prototype) are compared to three complementary midpoint categories using Life Cycle Assessment (Global Warming Potential, Material Resource Scarcity, and Human Non-Carcinogenic Toxicity). The results show that the studied circularity metrics generate accurate results when evaluating Material Resource Scarcity and that they rank the material efficiency strategies equally with all environmental impact categories. The circularity metrics are unable to capture the benefits of reduced energy and the correspondence to all impact categories is lower in scenarios with higher energy use. We conclude that the strength of the studied circularity metrics is twofold: i) promoting solutions that reduce material demand and waste creation and ii) highlighting the advantages of combining complementary circularity strategies. This research shows that the material-based circularity metrics can be valuable guidance tools for practitioners of circular economy, as they do not require methodological expertise and can align the results with Life Cycle Assessments in some specific situations. More comparisons between circularity metric results and Life Cycle Assessments are needed in future research to establish state-of-the-art circularity metrics for specific situations and purposes, including energy-focused circularity metrics.

The global environmental costs of mining and processing abiotic raw materials and their geographic distribution

The global demand for abiotic resources is rising, and continuous extraction has adverse effects on the environment. In this study, we quantify the total global environmental costs by monetizing the life cycle assessment results of mining and processing 38 abiotic materials. Results are shown in terms of material and affected country. We assess impacts covered by the ReCiPe impact assessment method, excluding impacts on freshwater and marine ecosystems and some crucial local and cultural impacts. Furthermore, we compare the environmental costs with the mining GDP for each country. The total environmental costs range from €0.4 to €5 trillion annually. We find that the highest absolute environmental costs can be attributed to the greenhouse gases, particulate matter emissions and acidification caused by coal and steel specifically. The countries with the highest absolute costs are China and India, because China extracts and processes large amounts of materials, while India carries a large share of the climate damages that global material production causes. The countries that have the most beneficial ratio of environmental costs per GDP are countries that process materials, such as Japan and Germany (steelmaking), and countries that mostly extract oil, as Algeria, Azerbaijan and Nigeria, because they largely externalize environmental costs of upstream and downstream processes. For materials that have a worse relationship between economic gains and environmental impact, or that have high down‑stream impacts such as fossil energy carriers, circular economy, material efficiency and substitution strategies should be prioritized to reduce global environmental degradation.

Improved Copper Circularity as a Result of Increased Material Efficiency in the U.S. Housing Stock.

Material efficiency (ME) can support rapid climate change mitigation and circular economy. Here, we comprehensively assess the circularity of ME strategies for copper use in the U.S. housing services (including residential buildings and major household appliances) by integrating use-phase material and energy demand. Although the ME strategies of more intensive floor space use and extended lifetime of appliances and buildings reduce the primary copper demand, employing these strategies increases the commonly neglected use-phase share of total copper requirements during the century from 23–28 to 22–42%. Use-phase copper requirements for home improvements have remained larger than the demand gap (copper demand minus scrap availability) for much of the century, limiting copper circularity in the U.S. housing services. Further, use-phase energy consumption can negate the benefits of ME strategies. For instance, the lifetime extension of lower-efficiency refrigerators increases the copper use and net environmental impact by increased electricity use despite reductions from less production. This suggests a need for more attention to the use phase when assessing circularity, especially for products that are material and energy intensive during use. To avoid burden shifting, policymakers should consider the entire life cycle of products supporting services when pursuing circular economy goals.

Assessing recycling, displacement, and environmental impacts using an economics‐informed material system model

Material production drives an increasingly large fraction of CO2-equivalent emissions. Material efficiency strategies such as recycling serve to reduce these emissions. Current analyses of the effectiveness of such strategies do not include economically induced rebound effects, overestimating the associated environmental benefits. We present a dynamic supply chain simulation model for copper through 2040 incorporating inventory-driven price evolution, dynamic material flow analysis, and life cycle assessment alongside mine-level economic evaluation of opening, closing, and production decisions. We show that permanent increases in recycling displace ∼0.5 kilotonnes mine production per kilotonne increase in scrap supply on average, while short-lived recycling policies can lead to increased mine production. We find evidence for supply chain evolution pathways minimizing the rebound effect and maximizing displacement of primary material, where increasing refined copper and concentrate prices and decreasing demand serve to decrease mining. However, even in best-case scrap supply scenarios, CO2e emissions from the copper sector increase 25% by 2040 relative to 2018 due to demand growth, ore grade decline, and lower displacement among large scrap supply changes. With implementation of best available technologies across all supply chain components, we estimated 2040 CO2e emissions 10% below those of 2018 are possible, though still well short of 2°C emissions targets. We find increasing mine taxes and royalties, reclamation costs, and exploration costs further increase displacement, as does the inclusion of scrap prices on major futures exchanges. These results highlight the importance of considering the economics of the entire material supply chain when implementing material efficiency strategies. This article met the requirements for a Gold-Gold JIE data openness badge described at http://jie.click/badges.

Energy and material efficiency strategies enabled by metal additive manufacturing – A review for the aeronautic and aerospace sectors

Conventional manufacturing of aeronautic and aerospace parts requires substantial amount of resources (energy and materials) while generating high quantities of waste and carbon dioxide emissions. Metal additive manufacturing (MAM) has the potential to reduce resource consumption, which is particularly important for energy-intensive materials such as titanium. We undertake a systematic literature review of MAM processes for the aerospace/aeronautic sector focusing on energy and material efficiency. Relevant literature was classified and discussed based on the life cycle stages at which resource efficiency strategies for MAM were identified: (1) product design; (2) material development and sourcing; (3) processes development, control, and optimization; (4) end-of-life extension and circular economy. Results highlight the key factors required to optimize MAM and the relevance of assessing its environmental impact compared to conventional manufacturing. Material and energy efficiency vary significantly between different MAM processes due to several factors directly linked to the process but also associated with the supply chain, e.g. electricity mix or material sourcing. Further research could explore new trends in technological development for circularity or multi-material MAM.

Low-Carbon Development for the Iron and Steel Industry in China and the World: Status Quo, Future Vision, and Key Actions

The low-carbon development of China’s iron and steel industry (ISI) is important but challenging work for the attainment of China’s carbon neutrality by 2060. However, most previous studies related to the low-carbon development of China’s ISI are fragmented from different views such as production-side mitigation, demand-side mitigation, or mitigation technologies. Additionally, there is still a lack of a comprehensive overview of the long-term pathway to the low-carbon development of China’s ISI. To respond to this gap and to contribute to better guide policymaking in China, this paper conducted a timely and comprehensive review following the technology roadmap framework covering the status quo, future vision, and key actions of the low-carbon development of the world and China’s ISI. First, this paper provides an overview of the technology roadmap of low-carbon development around the main steel production countries in the world. Second, the potential for key decarbonization actions available for China’s ISI are evaluated in detail. Third, policy and research recommendations are put forward for the future low-carbon development of China’s ISI. Through this comprehensive review, four key actions can be applied to the low-carbon development of China’s ISI: improving energy efficiency, shifting to Scrap/EAF route, promoting material efficiency strategy, and deploying radical innovation technologies.

Global greenhouse gas emissions from residential and commercial building materials and mitigation strategies to 2060

Building stock growth around the world drives extensive material consumption and environmental impacts. Future impacts will be dependent on the level and rate of socioeconomic development, along with material use and supply strategies. Here we evaluate material-related greenhouse gas (GHG) emissions for residential and commercial buildings along with their reduction potentials in 26 global regions by 2060. For a middle-of-the-road baseline scenario, building material-related emissions see an increase of 3.5 to 4.6 Gt CO2eq yr-1 between 2020–2060. Low- and lower-middle-income regions see rapid emission increase from 750 Mt (22% globally) in 2020 and 2.4 Gt (51%) in 2060, while higher-income regions shrink in both absolute and relative terms. Implementing several material efficiency strategies together in a High Efficiency (HE) scenario could almost half the baseline emissions. Yet, even in this scenario, the building material sector would require double its current proportional share of emissions to meet a 1.5 °C-compatible target.

Emission reduction strategies in the EU steel industry: Implications for business model innovation

AbstractThe European steel industry must achieve deep greenhouse gas emission reductions to become climate neutral by 2050. New business models are often proposed as one of the key solutions but are mostly addressed in general terms, without elaborating on or systematically analyzing how these new business models are actually linked to specific mitigation measures or strategies. In this paper, we assess when and to what extent different emission reduction strategies in the EU steel industry have implications for business model innovation. Through a review of 42 recent publications on industrial decarbonization, we identify 9 types of decarbonization strategies for steelmaking and their emission reduction potential. The strategies achieve emission reductions through material efficiency, emission efficiency, or a combination of both. For each strategy, we analyze the need for incremental or radical changes in business models on the basis of a thorough reading of the business model literature. Our findings show that EU steel firms can pursue several strategies to decarbonize without having to radically innovate their business models. Importantly, material efficiency strategies, arguably key to decarbonization, imply more radical changes to business models than emission efficiency strategies. Our study is a first contribution to the systematic assessment of industrial decarbonization strategies from a business model perspective. It is also an attempt to bring more rigor to the understanding of the role of business models in industrial decarbonization.

Reducing the carbon footprint of ICT products through material efficiency strategies: A life cycle analysis of smartphones

AbstractWith the support of a life cycle assessment model, this study estimates the carbon footprint (CF) of smartphones and life cycle costs (LCC) for consumers in scenarios where different material efficiency strategies are implemented in Europe. Results show that a major contribution to the CF of smartphones is due to extraction and processing of materials and following manufacturing of parts: 10.7 kg CO2,eq/year, when assuming a biennial replacement cycle. Printed wiring board, display assembly, and integrated circuits make 75% of the impacts from materials. The CF is increased by assembly (+2.7 kg CO2,eq/year), distribution (+1.9 kg CO2,eq/year), and recharging of the device (+1.9 kg CO2,eq/year) and decreased by the end of life recycling (−0.8 kg CO2,eq/year). However, the CF of smartphones can dramatically increase when the energy consumed in communication services is counted (+26.4 kg CO2,eq/year). LCC can vary significantly (235–622 EUR/year). The service contract can in particular be a decisive cost factor (up to 61–85% of the LCC). It was calculated that the 1:1 displacement of new smartphones by used devices could decrease the CF by 52–79% (excluding communication services) and the LCC by 5–16%. An extension of the replacement cycle from 2 to 3 years could decrease the CF by 23–30% and the LCC by 4–10%, depending on whether repair operations are required. Measures for implementing such material efficiency strategies are presented and results can help inform decision‐makers about how to reduce impacts associated with smartphones.

A comprehensive set of global scenarios of housing, mobility, and material efficiency for material cycles and energy systems modeling

Scenario-based assessments are a useful tool to explore unknown futures and inform decision makers and the public of the consequences of different courses of action. Scenario developments in industrial ecology have focused on disparate components of the socioeconomic metabolism and case studies, and few efforts of comprehensive and cumulative scenario formulation are documented. Many important, empirically derived relationships between material cycles, end-use services, and energy use are relevant to global scenario modeling efforts, for example, of integrated assessment models (IAMs), which do not routinely describe material cycles or the life-cycle impacts of various technology shifts. These inconsistent depictions of material cycles and their environmental impacts hinder the assessment of sustainable development strategies such as demand-side sufficiency, material efficiency, and energy efficiency. We developed three highly detailed scenarios covering 20 global regions to 2060 for the service provisioning of dwelling area and personal transport grounded in salient building and vehicle operation parameters. Our scenarios are based on, and interface with, the Low Energy Demand (LED) and Shared Socioeconomic Pathways (SSP1 and SSP2) narratives. The results comprise scenario-, region-, and period-specific narratives and corresponding parameter values, including per-capita floor space and vehicle stocks, building and vehicle archetype mixes, passenger-km, vehicle-km, vehicle occupancy rates, and implementation potentials of nine material efficiency strategies. The explicit storyline extension approach presented here is an alternative to the aggregate GDP-driven or historical trend extrapolations of service or energy demands. We describe the scenario formulation processes, resulting parameters, their applications, and offer an outlook for prospective sustainability models. This article met the requirements for a Gold-Gold JIE data openness badge described at http://jie.click/badges.

Copper Recycling Flow Model for the United States Economy: Impact of Scrap Quality on Potential Energy Benefit.

Is recycling a means for meeting the increasing copper demand in the face of declining ore grades? To date, research to address this question has generally focused on the quantity, not the quality of copper scrap. Here, the waste input–output impact assessment (WIO-IA) model integrates information on United States (US) economy-wide material flow, various recycling indicators, and the impact of material production from diverse sources to represent the quantity and quality of copper flows throughout the lifecycle. This approach enables assessment of recycling performance against environmental impact indicators. If all potentially recyclable copper scrap was recycled, energy consumption associated with copper production would decrease by 15% with alloy scrap as the largest contributor. Further energy benefits from increased recycling are limited by the lower quality of the scrap yet to be recycled. Improving the yield ratio of final products and the grade of diverse consumer product scrap could help increase copper circularity and decrease energy consumption. Policy makers should address the importance of a portfolio of material efficiency strategies like improved utilization of copper products and lifetime extension in addition to encouraging the demand for recycled copper.

What Key Drivers Are Needed to Implement Material Efficiency Strategies? An Analysis of the Electrical and Electronic Industry in Malaysia and Its Implications to Practitioners

A circular economy can be achieved by the efficient use of materials across different industries and sectors. In the manufacturing sectors, practicing material efficiency is one of the effective strategies to reduce material usage and solid waste generation. However, due to many unknown factors, such as key drivers to enhance material efficiency, most of the time, manufacturers are practicing at the minimum level of material saving. This study aims to examine the key drivers of material efficiency among electrical and electronic (E&E) companies to fulfill the aims of sustainable manufacturing. The data collection and synthesis were conducted using semi-structured interviews and an analytical hierarchy process survey. In this study, thirteen key drivers were found. Five internal drivers and eight external drivers with different priorities were found to influence E&E companies in the practice of material efficiency strategies. In addition, the drivers’ implications to different practitioner groups are suggested. To conclude, achieving material efficiency can be done effectively if the incentivized key drivers are clearly notified. This research is important to show the key drivers that influence the implementation of material efficiency strategies in the E&E industries.