• Energy Research

AbstractInternational trade is essential to bridge the imbalance between supply and demand of materials along with different nations effectively, especially for critical raw materials such as tungsten that are highly geographically unequally distributed. However, the international trade flows and their complex networks that link those participating nations have remained largely unexplored, which leads to inexplicable concerns for materials' criticality and their supply risks. By integrating the material flow analysis and the complex network analysis, this study traces the global trade flows of tungsten in various forms ranging from primary products to scrap among 223 countries and regions annually from 2000 to 2018 and explores the evolution of participating countries' role involved in international trade networks from both physical and monetary perspectives. We found that (1) there are ∼2673 thousand metric tons of tungsten feeding into supply chains globally during the 19 years, and about 96% of tungsten resources are re‐allocated from Asia to the high‐income regions; (2) the high‐income countries gain the potential benefits from both the resources and economic perspectives and they import 72% of tungsten resources in the form of primary and semi‐products from developing countries, meanwhile earning 87% of global tungsten trade value by exporting tungsten metal products with high value‐added back to those tungsten resources suppliers. Under the growing national interconnections of global tungsten trade networks, this study urges more cooperative actions and targeted supply chain management among the participating countries to secure the tungsten supply and sustainability of the global tungsten cycle.

Abstract Plastics are the paradigmatic material of the current era. Plastics’ trade articulates interest in trading partnerships and concerns about trade security. We focus on the International Plastic Resin Trade Network (IPRTN) and analyze its spatiotemporal evolution in 1988–2017 from global, regional, and national scales. As a profile of globalization, the network became increasingly interconnected under the combined effect of the involvement of more participating countries, the increase in the closeness of trade links, and the increase in trade volume, which grew by 0.4-fold, 7.7-fold, and 14.9-fold, respectively. Despite the growth, IPRTN maintained fairly stable topological characteristics including small-world property (average path length, 1.95 ± 0.10; clustering coefficient, 0.63 ± 0.06), high reciprocity (reciprocity value, 0.54 ± 0.03), disassortative mixing (assortativity value, −0.46 ± 0.23), and exponential degree distribution. Generally, the plastic resin trade was spatially heterogeneous with high intra-regional trade proportions (1988–1997, 78.4%; 1998–2007, 79.9%; 2008–2017, 75.1%), and Europe, Asia, and North America were the dominating regions. These facts brought IPRTN with a regionally dependent community structure. Five communities were finally formed: the Middle East-Africa community, the Eastern Europe community, the Western Europe community, the Americas community, and the East Asia-Southeast Asia-Oceania community. We found that the US-China plastic resin trade was mainly complementary. Thus, mutual tariffs in the US-China trade war, which covers plastic resins, will cause adverse effects and need to be resolved through active consultations. To ensure trade security, we remind countries with poor trade robustness to pay attention to changes in trade policies of these critical trade players and to enrich trade channels.

Solid waste recycling is crucial for easing China's resource constraints and for promoting the country's sustainable economic development. Previous studies regarding solid waste recycling have mainly assessed its economic value, the status quo, problems and challenges, however, little is known at this stage about its driving factors. The purpose of the current study is to identify the socioeconomic drivers of solid waste recycling, investigating it's evolution in China from 2005 to 2017. The study employs a systematic technique of input-output (IO) analysis and IO-based structural decomposition analysis (IO-SDA). Results reveal that China experienced an increase in the recycling of five types of solid waste, these include waste steel, waste nonferrous metals, waste plastics, waste paper and waste rubber for the period 2005-2017. The increase in solid waste recycling was driven mainly by fixed capital formation and exports, while urban household consumption was found to be a dominant driver due to China's increasing urban population. In order to better track and identify the recycling of solid waste, there is an urgent need to promote the classification of household solid waste at the national level. An increase of solid waste recycling was driven mainly by the growth of recycling intensity, population increase and changes in the structure of GDP, which was partly offset by per capita GDP changes. It is recommended that policy-makers increase the amount of investment in solid waste recycling capacity in rural areas so as to enhance recycling intensity contributing to the overall recycling effort.

Abstract CO2 emissions mitigation in iron and steel industry (ISI) and construction material industry (CMI), including cement, glass, and ceramics materials, is crucial for the realization of CO2 emission peak targets in China, given their great contributions to China’s emission structure. Great transitions have occurred in the two industries recently, including scale expansion, efficiency improvement, and changes in production and demand structures. By developing an integrated framework for inter-sector linkage analysis, we investigated the impact of recent transitions in the ISI and CMI on China’s CO2 emissions between 1992 and 2012. Results show that the CO2 emissions from ISI and CMI increased by 4.2 and 6.8 times over two decades, respectively, and the two key sectors have significantly higher backward and forward linkages than average in terms of CO2 emissions. The internal efficiency improvement of the ISI and CMI are crucial factors curbing the rising CO2 emissions in these two sectors. The total CO2 intensity of the ISI and CMI have declined by 78% and 68%, separately, cumulatively reducing 517 Mt and 704 Mt CO2 emissions during the studied period. The external final demand growth and its structure changes of the ISI and CMI have had a significant impact on their CO2 emissions. The construction sector is the greatest consumer, responsible for 53% and 86% emissions increase of ISI and CMI during 2002–2012, respectively. Emerging manufacturing and machinery also became substantial emissions sources, generating 536 Mt CO2 emissions in 2012 by consuming iron and steel products. Based on these findings, policy recommendations for CO2 emissions mitigation in the two key sectors and their related sectors are also discussed.

Abstract China is accelerating automotive electrification to address the pressing oil shortage and environmental pollution issues. Automotive electrification can be achieved through four different major technology pathways: hybrid electric vehicles, plug-in hybrid electric vehicles, battery electric vehicles and fuel cell electric vehicles. These pathways all heavily rely on the use of critical mineral resources, such as rare earth elements (REEs). This study establishes different scenarios of the future technology mix and growth in automotive electrification in China by 2030 to predict the future demand of REEs associated with such scenarios. The widely applied Bass model is chosen to predict the future growth of these four technology pathways for electric vehicles under pessimistic, neutral and optimistic demand scenarios. Given the potential for technological advances, the effects of changes in the material intensity and component substitution are considered to effectively reflect future demand changes. Accordingly, the REE demand associated with the four technology pathways from 2018 to 2030 is estimated. The highest demand for REEs in automotive electrification will reach 315 thousand tons, accounting for 22% of global production during the prediction period. Specifically, the demands for Nd, Dy, Ce, Pr, and La will account for 51%, 20%, 12%, 9.5%, and 7.7% of the total demand, respectively. Moreover, the contrast between the supply and demand of Dy and Pr will be extremely large, and these elements will require more attention than others. For the successful development of automotive electrification in China, related policies and plans regarding the supplies of different types and quantities of REEs should be urgently established.

Abstract Over the past decade, the global aluminum industry has undergone profound changes, particularly as a result of China emerging as a powerhouse production base, accounting for approximately 60% of global smelting capacity by the end of 2018. To explore the potential energy conservation and CO2 emission reduction of China's aluminum industry during 2010–2050, we developed a comprehensive assessment framework based on quasi-dynamic material flow analysis, energy consumption, and CO2 emission models. Four scenarios were designed to outline future energy savings and CO2 emission mitigation in China's aluminum industry. The results show that China's aluminum demand will consistently increase from 22.67 Mt in 2010 to 51.20 Mt in 2050. In the short term, China's aluminum industry cannot achieve a completely circular economy without implementing new policies. The results also indicate that the energy intensity and CO2 emissions per ton of aluminum will gradually decline under the multiple effects of technology promotion and structure adjustment. Under all four scenarios, the strengthened policy (STP) scenario has the least total energy consumption (TEC), reaching 46.57 Mtce and 24.11 Mtce in 2030 and 2050, respectively. The effect of energy conservation and emission reductions brought about by adjusting the production structure was far higher than the increasing technology penetration rate.

AbstractThe adoption of electric vehicles (EVs) on a large scale is crucial for meeting the desired climate commitments, where affordability plays a vital role. However, the expected surge in prices of lithium, cobalt, nickel, and manganese, four critical materials in EV batteries, could hinder EV uptake. To explore these impacts in the context of China, the world’s largest EV market, we expand and enrich an integrated assessment model. We find that under a high material cost surge scenario, EVs would account for 35% (2030) and 51% (2060) of the total number of vehicles in China, significantly lower than 49% (2030) and 67% (2060) share in the base-line, leading to a 28% increase in cumulative carbon emissions (2020-2060) from road transportation. While material recycling and technical battery innovation are effective long-term countermeasures, securing the supply chains of critical materials through international cooperation is highly recommended, given geopolitical and environmental fragilities.