Research On Life-cycle Evaluation And Improving Path Of China’s Aluminum Resource Efficiency Under The Background Of “Carbon Peaking And Carbon Neutrality”

Aluminum is an important basic raw material for economic construction and the development of strategic emerging industries,national defense science and technology industry.It is also an important supporting raw material for clean energy transformation under the target of “carbon peaking and carbon neutrality”.As the largest producer and consumer of aluminum resources,the contradictions among high dependence on bauxite,low resource efficiency and high emissions are prominent,which not only threatens the realization of the “carbon peaking and carbon neutrality”target,but also is an obvious shortcoming to achieve high-quality development.Under such complex backgrounds,it is of great necessity to improve aluminum resource efficiency.Therefore,how to scientifically estimate the efficiency of aluminum resources and design the upgrade paths have become key problems to be solved.This study aims to assess the aluminum resource efficiency in China from a life-cycle perspective and to explore the improvement effects of aluminum resource efficiency under different paths.Firstly,this study analyzes the inner mechanism of how aluminum resource efficiency changes from the perspectives of return to scale effect and substitution effect;improves the theoretical mechanism of aluminum resource efficiency based on PSR model in the context of carbon peaking and carbon neutrality.Secondly,this study constructs an accounting framework for the flow and stock,energy consumption and carbon emission of aluminum resources in China from the life-cycle perspective based on the dynamic material flow analysis method.The flow and stock,energy consumption and carbon emission of aluminum resources at each stage of the whole life cycle from the mining stage to the waste management and recycling stage from 2000 to 2020 are calculated and analyzed.Thirdly,aluminum resource efficiency,which includes resource use efficiency and carbon emission efficiency,is evaluated and analyzed,and then the decoupling status of each life-cycle stages are estimated and judged.Fourthly,the influencing factors of aluminum resource efficiency in China are decomposed through the LMDI decomposition model which is expanded by factor endowment,investment and R&D input.Finally,a stock-driven model based on dynamic material flow analysis combined with rolling estimation method and scenario analysis is applied to forecast the improvement and variability of the aluminum resource efficiency for different life-cycle process under different paths.Corresponding policy recommendations to enhance aluminum resource efficiency are proposed according to findings in this study.The main findings are as follows:(1)China has become the greatest producer and consumer of aluminum,but aluminum supply and demand in different life-cycle process are imbalanced.During 2000-2020,the importing scale of bauxite in China was in an increasing trend.However,the refining process has accumulated excess production of aluminum.The construction sector has been the largest consumer of aluminum resources in China.With the trend of light-weighting and new energy for vehicles,the consumption of aluminum resources for transportation has been increasing.in 2020,the accumulative aluminum stocks in the use process reached 265.42 million tons.At present,the production of recycled aluminum is limited,which is not sufficient to fix out the high external dependence on bauxite.(2)During 2000-2020,the total energy consumption and carbon emissions of China’s aluminum resource production rose sharply.The proportion of carbon emissions in the smelting process was the largest among 6 aluminum production processes and its proportion kept increasing.The carbon emission intensity of secondary aluminum production is only about 5% of that of primary aluminum production.On the whole,the decoupling state between aluminum resource use and GDP were worse than that between carbon emissions and GDP.(3)The efficiency of aluminum resource use as a whole has a fluctuating downward trend.In terms of the absolute value of efficiency,the resource use efficiency in the upstream mining stage is the lowest,and the carbon emission efficiency is the lowest in the smelting and processing stage.The aluminum resource intensity of the aluminum industry chain is higher than the capital intensity than the labor intensity.R&D intensity and R&D efficiency are the most important influencing factors of aluminum resource efficiency.(4)The demand for aluminum resources in the transportation sector is expected to become the largest since 2024.The peak of aluminum demand may appear in 2026 under the prediction.In 2050,domestic produced bauxite in China is expected to be fully replaced by imported bauxite and recycled aluminum.All selected paths show significant improving effects on aluminum resource saving and carbon emissions.(5)Resource saving path and recycling path plays the best at improving resource use efficiency of aluminum.In the long run,energy structure optimization is a better path for the improvement of carbon emission efficiency than decreasing energy intensity.The main contributions of this study are as follows:(1)Analyzes the inner mechanism of how aluminum resource efficiency changes from the perspectives of Return to scale effect and substitution effect,and constructed a pressure-state-response(PSR)conceptual model of aluminum resource efficiency under the target of “carbon peaking and carbon neutrality”,which provides a scientific and systematic analyzing framework for studies on metal resource efficiency,and expands the application of PSR model in the field of resource efficiency.(2)From the perspective of whole life cycle of aluminum resources,this study takes resource consumption,environmental output and economic output into one framework,which allows to evaluate metal resource efficiency in a comprehensive,multi-dimensional and whole-process way.This optimizes the traditional metal resource efficiency assessment indexes,and enriches the theory and evaluating method for resource efficiency.(3)By using the LMDI decomposition model expanded by factor endowment,investment and R&D input,analyzes the return to scale effect and substitution effect on changes in aluminum resource efficiency.This makes up the shortcomings of existing studies that tend to ignore micro factors such as production factors and technological progress when decomposing influencing factors.(4)Combining the aluminum resource demand forecasting model,rolling estimation method and scenario analysis method,this study quantified the optimization effects of different efficiencyimproving paths and put forward targeted policy.It can also provide reference for the study of resource efficiency of other strategic metals.