Journal of Environmental Management 134 (2014) 30e38

Contents lists available at ScienceDirect

Journal of Environmental Management journal homepage: www.elsevier.com/locate/jenvman

Performance analysis of CO2 emissions and energy efficiency of metal industries in China Chaofeng Shao a, *, Yang Guan a, Zheng Wan b, Chunli Chu a, Meiting Ju a a b

College of Environmental Science and Engineering, Nankai University, 94 Weijin Road, Nankai District, Tianjin 300071, China College of Transport and Communications, Shanghai Maritime University, Shanghai 201306, China

a r t i c l e i n f o

a b s t r a c t

Article history: Received 26 September 2013 Received in revised form 23 December 2013 Accepted 26 December 2013 Available online 23 January 2014

Nonferrous metal industries play an important role in China’s national economy and are some of the country’s largest energy consumers. To better understand the nature of CO2 emissions from these industries and to further move towards low-carbon development in this industry sector, this study investigates the CO2 emissions of 12 nonferrous metal industries from 2003 to 2010 based on their lifecycle assessments. It then classifies these industries into four “emissioneefficiency” types through cluster analysis. The results show that (1) the industrial economy and energy consumption of China’s nonferrous metal industries have grown rapidly, although their recent energy consumption rate shows a declining trend. (2) The copper, aluminum, zinc, lead, and magnesium industries, classified as highemission industries, are the main contributors of CO2 emissions. The results have implications for policy decisions that aim to enhance energy efficiency, particularly for promoting the transformation of lowefficiency industries to high-efficiency ones. The study also highlights the important role of policy development in technological innovations, optimization, and upgrades, the reduction of coal proportion in energy consumption, and the advancement of new energy sources. Ó 2014 Elsevier Ltd. All rights reserved.

Keywords: Nonferrous metal industries Cluster analysis CO2 emission Energy efficiency

1. Introduction Climate change has caused widespread concern throughout international and domestic communities, and formulating an effective response to climate change has become a major thrust in all levels of government planning in China (Bao, 2010; Li et al., 2011). According to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC, 2007), the key factor in climate change is the increase in carbon emissions during energy consumption processes. Nonferrous metal industries, including the copper, aluminum, lead, zinc, nickel, tin, antimony, mercury, magnesium, titanium, tungsten, and molybdenum industries, are some of the largest energy consumers in China. According to the China Statistical Yearbook (National Bureau of Statistics of China, 2012), the 2010 energy consumption of nonferrous metal industries in China was 13,795.61
104 tce, accounting for 4.24% of China’s total energy consumption and ranking the sectors 11th among 49 industries. According to the Twelfth Five-Year Development Plan for

* Corresponding author. Tel.: þ86 13820685571; fax: þ86 22 23506446. E-mail address: [email protected] (C. Shao). 0301-4797/$ e see front matter Ó 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jenvman.2013.12.025

the Nonferrous Metal Industry, the nonferrous metal sector in China should adjust its industrial structure, improve its resource security, accelerate its technological progress, strengthen its prevention efforts against heavy metal pollution, vigorously promote energy conservation, and eliminate its outdated smelting production technologies. Improving energy efficiency is the most important strategy to limit carbon emissions from nonferrous metal industries. Therefore, to reduce total industrial carbon emissions in China and to promote sustainable and low-carbon industry practices, carbon emissions from the nonferrous metal industries must be curtailed. In the interest of limiting carbon dioxide (CO2) emissions attributed to nonferrous metal industries, local and international scientists and engineers have studied carbon emissions from nonferrous metal industries. Ijima and Harada (2001) estimated CO2, SOx, and NOx emissions form nonferrous metal processing through a “cradle-to-grave” assessment that uses the 1999 economic statistical yearbook and compared the results with 1989 data. The authors found that the greater part of emissions is attributed to foreign countries. Wang and Chandler (2010) investigated and provided an overview of the energy use and CO2 emissions of nonferrous metal industries in China, including the six most common nonferrous metal industries (copper, aluminum,

C. Shao et al. / Journal of Environmental Management 134 (2014) 30e38

zinc, lead, nickel, and tin), from a CO2 emission reduction perspective. Kuckshinrichs et al. (2007) discussed trends in technical progress and the increased use of recycled metal as they relate to the potential for sustainable development in copper material flow, with respect to CO2 and sulfur emissions. Ren et al. (2011) compared the carbon footprint of aluminum industries in China and internationally from 2000 to 2009 and showed that reducing the carbon footprint of electrolytic aluminum, specifically in its electrical power use, is the key to reducing the carbon footprint in the aluminum industry. However, each of these studies addressed either the carbon emissions of a single metal industry only or those of all nonferrous metal industries as one entity. Guan et al. (2013a) accounted the carbon footprint of China’s lead industry and made a comparative analysis of the carbon sink forest costs and income of such industry. These studies have not examined the carbon emissions of two or more metal industries or analyzed the “emissione efficiency” combinations of all 12 nonferrous metal industries. Furthermore, these studies did not compare the relationship of the development of energy efficiencies between the nonferrous metal industries or propose potential adjustment programs or CO2 emissions control strategies. The life-cycle assessment (LCA) method (Guinee et al., 2006; Dini˛er and Zamfirescu, 2011) is useful to evaluate CO2 emissions in nonferrous metal industry production processes and has been widely applied in carbon accounting. Although LCA is widely used to evaluate the environmental effect of services, products, and processes, LCA information for metal production is limited. A few LCA studies have been devoted to metal production, including Itsubo and Yamamoto (1999), who proposed a method of assessment for total impact in Japan and performed a case study of LCA concerning nonferrous metals. The authors found that air pollution and resource depletion severely affect the production of aluminum and the stages of consumption of non-oil resources. The authors also indicate that the production of non-oil-based fuels adversely impact the production of zinc because a large quantity of non-oil resources (e.g., coke) are consumed, and interpretations will differ if the criterion for material assessment is modified from weight (per kg) to tensile strength. Norgate et al. (2007) used LCA to assess the cradle-to-grave environmental effect of some metal production processes practiced either currently or potentially in Australia, and concluded that new process technologies for primary metal production can be expected to reduce the environmental effect of metal production. The authors estimated the likely reductions for technologies involving stainless steel, titanium, and aluminum. Norgate and Haque (2012) estimated the environmental footprint of gold production using LCA, determining that the mining and comminution stages are gold production’s greatest contributing factors to the greenhouse gas footprint. These findings emphasize the need to focus on these stages to reduce the embodied energy and greenhouse gas footprint of gold production. Guan et al. (2013b) used the carbon footprint method based on the LCA method, to account for the carbon footprint attributed to copper and aluminum usage in the Chinese indoor air conditioner industry from 2000 to 2009. The researchers also analyzed the developing trend of aluminum substitution for copper and proposed a cooperative control strategy to limit the carbon footprint and to guide the development of the Chinese indoor air conditioner industry. A short description of previous research is shown in Table 1. Using LCA, the current study describes the CO2 emissions from the production processes (including mining, milling, half-product production, smelting, rolling, and processing) of 12 main nonferrous metal industries in China between 2003 and 2010. Through cluster analysis, these 12 industries are classified into four different types, namely, high emissionehigh efficiency (HEMeHEF), high

31

Table 1 Main finding from previous research. Item

Region

Ijima and Harada, 2001

Japan

Nonferrous Main conclusion metals

Cu, Pb, Zn, Calculation of CO2, SOx, NOx emissions form nonferrous metal and Al production process based on economic statistics was carried out, and the greater part of emissions were attributed to foreign countries. China Cu, Al, Pb, Energy efficiency of large-scale Wang and enterprises in China is not particularly Zn, Sn, Chandler, low compared to international and Ni 2010 practice, but small- and mediumsized enterprises rank low. Backward production capacity would be phased out continuously by enforcing the energy intensity norms. Kuckshinrichs Global Cu Technical progress and increased use et al., 2007 of recycled metal are important measures for alleviating the shortage of copper resources and limiting emissions from copper production. Ren et al., 2011 China Al The carbon footprint of the Chinese aluminum industry increased from 2000 to 2009; the electrolytic aluminum process is a major source of greenhouse gas emissions. Japan Al and Zn The impacts of eutrophication, air Itsubo and pollution, and resource depletion Yamamoto, impose severe effects on the 1999 production of aluminum. The stages of the production and consumption of non-oil resources exert severe effects on the production of zinc. Interpretations will differ if the criterion for material assessment is modified from weight (per kg) to tensile strength. Norgate Australia Cu, Al, Pb, Many factors or parameters are et al., 2007 Zn, Ni associated with a particular metal production process, influencing the “cradle-to-gate” environmental impacts of a process. These factors include ore grade, electricity energy source, fuel types, and material transport, as well as process technology. New technology developments for both existing and alternative metal production processes can reduce the environmental impacts of metal production. Norgate and Australia Au The mining and comminution stages Haque, 2012 made the greatest contribution to the greenhouse gas footprint of gold production, with electricity being the major factor and being responsible for more than half of the greenhouse gas footprint. Guan et al., China Lead The carbon footprint of the Chinese 2013a lead industry increased from 2000 to 2009. This increase is primarily attributed to the growth in refined lead output and the slow development of lead production technology; after 2005, the revenues of the Chinese lead industry were higher than the carbon sink forest costs mainly because of the rapid rise in lead price. Cu and Al The carbon footprint of the Chinese Guan et al., China indoor air conditioner industry 2013b (Indoor air generally declined during this period conditioner mainly because of the improvement industry) in copper and aluminum production technology.

32

C. Shao et al. / Journal of Environmental Management 134 (2014) 30e38

emissionelow efficiency (HEMeLEF), low emissionehigh efficiency (LEMeHEF), and low emissionelow efficiency (LEMeLEF). The relative emissioneefficiency features of these groups are discussed. This study also examines the emission and efficiency characteristics of the key nonferrous metal industries and proposes measures for low-carbon development. Section 2 describes the systematic methodology of this study, including the pretreatment of the original data and the application of LCA. Section 3 presents the carbon emission accounting process used in this paper and the CO2 emissions results for each nonferrous metal industry from 2003 to 2010. Section 4 presents the cluster analysis method and the emissioneefficiency features of the 12 nonferrous metal industries. Finally, Section 5 provides the comments and conclusions.

Therefore, with the method introduced by the Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse Gas Inventories (IPCC, 2006), carbon emissions from energy consumption can be calculated as follows:

CE ¼

n X

  Ci eCO2 i þ eCH4 i lCH4 i þ eCF4 i lCF4 i þ eNOxi lNOxi

(1)

i¼1

2. Methodology

where i is the type of energy (major energy sources include coal, coke, and electricity); CE is the total greenhouse gas emissions (converted into CO2, 104 t); Ci is the energy consumption of type i energy (104 t); eCO2 i , eCH4 i , eCF4 i , and eNOxi are the emission factors of type i energy; and lCH4 i , lCF4 i , and lNOxi are the coefficients for converting CH4, CF4, and NOx into CO2.

2.1. Research framework

2.3. Life-cycle analysis

Fig. 1 shows the basic research process used in this study. First, basic data on nonferrous industries in China were collected, including data on energy consumption during metal production, as well as output of metals and their intermediate products, from 2003 to 2010. Second, the data collected were pretreated and the current situation of nonferrous metal industries in China was analyzed. Third, through LCA, the CO2 emissions of the 12 nonferrous metal industries from 2003 to 2010 were calculated, and the industries were further classified into four types by cluster analysis. Finally, based on the results, the development tactics and transformation strategy of nonferrous metal industries in China were discussed.

This study includes an LCA of the production processes in nonferrous metal industries in China from 2003 to 2010. The LCA applied in this study follows the steps outlined in Standard 14040 of the International Organization for Standardization:

2.2. Method for calculating CO2 emissions According to the International Energy Agency (IEA, 2009), the CO2 emissions coming from the production processes of nonferrous metal industries (such as primary aluminum smelting) include gases such as CH4, NOx, and fluorocarbon, which are also important contributors to the greenhouse effect and climate change.

1. Determination of assessment scope and boundaries 2. Selection of the inventory of input and output 3. Assessment of data on environmental effects compiled in the inventory 4. Interpretation of results and suggestions for improvement

2.3.1. Scope of life-cycle analysis The overall scope of China’s nonferrous metal industries includes the stages of mining, milling, half-product production, smelting or electrolysis, rolling, and processing (Fig. 2). This study aims to use LCA to evaluate China’s nonferrous metal production processes and their environmental effects, and to identify possibilities for improving the environmental performance of these processes.

Fig. 1. Research framework.

C. Shao et al. / Journal of Environmental Management 134 (2014) 30e38

33

2.3.2. Relevant parameters According to data from the US Energy Information Administration (2009), burning 1 million BTUs of industrial coal results in 93.71 kg, 10 g, and 1.5 g of CO2, CH4, and NOx emissions, respectively. The coefficients used to convert CF4, NOx, and CH4 into CO2 are 6,500, e12, and 25, respectively (International Aluminum Institute, 2008; Working Group 1, 2007).

In this paper, using Euclidean distance, the total amount of CO2 emissions from energy consumption is considered the relative emission indicator (Em) and emission intensity is regarded as a relative emission efficiency indicator (Ef). The distance between two samples is calculated by following formula:

2.3.3. Life-cycle inventory According to the literature, although LCA is widely used and several different methods have been proposed to account for and manage greenhouse gas emissions using LCA, existing practical application tools are weak. Some models, such as those proposed by the IPCC and the International Copper Study Group (Norgate, 2001), are hardly applicable at the industry level because they use a stationary life-cycle inventory (LCI) to calculate the carbon footprint for different years, neglecting yearly technological improvements and making LCA accounting susceptible to inaccuracies. To avoid these pitfalls, the Yearbook of China Nonferrous Metal Industry (Editorial Committee of Yearbook of China Nonferrous Metal Industry, 2004e2011) was selected as the LCI data source of this study, particularly for its energy consumption data on the Chinese copper and aluminum industries for each study year, instead of using stationary energy consumption data. This Yearbook’s non-ferrous metal industry statistics are provided by the Ministry of Information and Statistics of the China Nonferrous Metal Industry Association, the industry authority in China. The annual collection of data is coordinated by the State Council and the China Nonferrous Metal Industry Association, and is carried out by nonferrous metal industry authorities in the provinces, autonomous regions, and municipalities, as well as by various nonferrous metal enterprises and organizations. Other relevant data from the Commonwealth Scientific and Industrial Research Organization (Norgate, 2001), the International Aluminum Institute (International Aluminum Institute, 2008), and the United States Geological Survey (USGS, 2011) were used for reference and as supplement.

Sjk ¼

2.4. Cluster analysis Cluster analysis is a collective term covering a wide variety of techniques for delineating natural groups or clusters in data sets; it has been applied in many fields, including mathematics, computer science, and statistics o divide subjects into relatively homogenous clusters (Anderberg, 1973; Kaufman and Rousseeuw, 2009).

Sik ¼ ðEmi ; Efi Þ 

Emj ; Efj



rffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 2  2  Emi  Emj þ Efi  Efj dij ¼

(2)

Using SPSS software and the K-means clustering algorithm, this paper takes a K value of 4, classifying 12 nonferrous metal industries into four types: high emission-high efficiency (HEMe HEF), high emission-low efficiency (HEMeLEF), low emissionhigh efficiency (LEMeHEF), and low emission-low efficiency (LEMeLEF). 3. Results 3.1. Overview of the nonferrous metal industries in China The total CO2 emissions of the 12 nonferrous metal industries in China from 2003 to 2010 (Fig. 3) were calculated according to the IPCC Guidelines (IPCC, 2006). The calculation was based on the final energy consumption data from the China Energy Statistical Yearbook (National Bureau of Statistics of China, 2001e2011) and from the pollution census in China in 2003e2010, including the data on the consumption of major types of energy sources, such as coal, coke, and electricity. From 2003 to 2010 (Fig. 3), with China’s strong growth in the nonferrous metal industry sector, energy consumption by the nonferrous metal industries steadily increased. The average annual growth of energy consumption was 15.04%, which is still lower than the growth rate of the industrial added value (29.31%) over the same period. The industrial added value is a basic indicator of national accounts; it is the average that nonferrous metal industries created and from which the value of consumption goods and services were deducted. This value can reflect the level of development of an industry. Under the combined effect of technological progress, the promotion of environmental protection practices in industrial activities, the introduction of recycling techniques in nonferrous metal industries, and other mitigating factors, the rate

Fig. 2. Life-cycle stages of China’s nonferrous metal industries.

34

C. Shao et al. / Journal of Environmental Management 134 (2014) 30e38

Fig. 3. Nonferrous metal industries’ economic and energy consumption trends in China from 2003 to 2010.

of industrial energy consumption showed a rapidly declining trend, decreasing from 4.87 tce/108 yuan in 2003 to 1.78 tce/108 yuan in 2010da 63.52% decrease. This decline indicates that concurrent with high-speed technology development, efforts by China’s nonferrous metal industries to limit carbon emissions and to implement low-carbon transition have produced some positive results. 3.2. CO2 emission results Using the 2010 LCI data for copper as an example, energy consumption and greenhouse gas emissions are described at every production stage of the copper industry in China (Table 2). The CO2 emissions of the 12 nonferrous metal industries in China from 2003 to 2010 are listed in Table 3. Table 3 shows the following information: (1) CO2 emissions from the aluminum industry were high, contributing the most to the total CO2 emissions (an average of 79.66% during the 2003e 2010 period), and increased dramatically at an annual rate of 14.24%. (2) The copper industry contributed the second highest CO2 emissions, accounting for an average of 7.29% of the total during the 2003e2010 period, but declined from 1418.03
104 t in 2003 to 1143.70
104 t in 2010da drop of 19.35%. (3) The CO2 emissions of the zinc, lead, and magnesium industries contributed 6.53%, 1.85%, and 3.38%, respectively, to the total emissions and increased significantly over the eight-year period. (4) Although the CO2 emissions of the titanium industry contributed an average of only 0.14% to the total emissions, these emissions increased significantly over the eight-year period, increasing by 52.30%. (5) Because of their low output and small-scale production levels, the CO2 emissions from the six other nonferrous metal industries accounted for only 1.40% of the total. The increases in CO2 emissions by the nickel, tin, antimony, tungsten, and molybdenum industries were not significant.

3.3. Emission intensity To understand the relationship between CO2 emissions and energy efficiency, the emission intensities of each of the 12 nonferrous metal industries for the 2003e2010 period was investigated (Table 4). Overall, the carbon emission intensity of China’s nonferrous metal industries shows a declining trend characterized by two features. (1) A large gap in carbon emission intensity was observed among the high- and low-intensity industries. In 2010, nine of the industries (except the aluminum, zinc, and magnesium industries) had a carbon emission intensity lower than the average (1.008 t/104 yuan). The lowest carbon emission intensity was only 0.012 t/104 yuan (mercury), whereas the highest was 3.802 t/104 yuan (aluminum). The three industries with high emission intensities are those using electrolysis during metal smelting and production. To achieve low-carbon and sustainable development in the nonferrous metal industries, a reduction or elimination of electrolytic production is imperative. (2) All the nonferrous metal industries show an obvious decreasing trend over the study period. However, due to the rapid increase in overall carbon emissions, the rate of decline of carbon emission intensity for copper, zinc, nickel, tin, antimony, magnesium, and tungsten industries was low. 3.4. Cluster analysis results Fig. 4 illustrates that 12 different industries are divided into their respective emissioneefficiency types, with the center position indicating the center of gravity and the optimal emissioneefficiency combination for each type. The shadow area of the circles indicates the ratio of the industries’ industrial added value. Fig. 4 shows that most of the industrial added value (an average of 97.63%) came from the HEMeHEF and HEMeLEF nonferrous metal industries in China. Among these industries, the copper industry, which contributed 31.75% of the industrial added value, and

Table 2 Energy consumption and gas emissions from copper production in 2010.

Domestic/t Energy cost/type and quantity CO2 emission/kg NOx emission/kg CH4 emission/kg CF4 emission/kg

Underground mining-ore

Open-pit mining-ore

Milling- concentrate

Smelting-refined copper

Processing-copper semis

45494658 2.71 kg coal/t

38527508 0.45 kg coal/t

2549558 3.92 kg coal/t

4051300 589.06 kg coke/t 241.20 kg coal/t 834.26 electricity kWh/t

8736400 1099.12 electricity kWh/t

321295103.41 5141.21 34287.09 0

45181208.63 722.97 4821.52 0

26045063.42 416.76 2779.41 0

4266678371.00 68273.40 455319.70 0

6375231693.17 102013.49 680334.59 0

C. Shao et al. / Journal of Environmental Management 134 (2014) 30e38

35

Table 3 CO2 emissions from nonferrous metal industries in China from 2003 to 2010 (unit: 104 t). Items

2003

2004

2005

2006

2007

2008

2009

2010

Copper Aluminum Lead Zinc Nickel Tin Antimony Magnesium Titanium Mercury Tungsten Molybdenum

1418.05 9189.89 261.66 1191.51 79.32 74.84 54.01 431.99 4.57 0.10 9.21 2.96

1271.33 11598.94 309.38 1483.97 79.84 88.83 72.02 573.33 5.35 0.18 14.53 3.64

1507.28 12903.25 367.91 1459.81 81.81 92.00 62.77 612.27 8.91 0.17 14.22 5.56

1864.82 13977.62 367.62 1079.02 84.33 91.04 77.71 708.48 25.12 0.12 4.98 7.53

1294.05 16953.91 368.44 1092.43 111.69 77.39 86.31 933.73 49.72 0.12 4.80 13.32

1045.53 23097.89 375.96 1132.73 134.81 69.27 94.53 768.02 64.62 0.21 9.97 13.70

942.25 23599.13 406.99 1128.15 153.31 64.61 60.72 505.12 49.05 0.22 6.36 12.99

1143.70 22233.98 511.14 1413.30 164.23 69.77 54.39 866.73 47.55 0.25 7.56 11.93

the aluminum industry, which contributed 37.04%, are the two industries that will continue to play important roles in the development and economic growth of China’s nonferrous metal industry sector. The HEMeLEF type zinc and lead industries contributed 12.21% and 7.76% of the industrial added value, respectively, and are also important contributors to the nonferrous metals economy. The LEMeHEF and LEMeLEF type industries contributed a low proportion of the overall industrial added value (about 2.37%). Accordingly, it can be concluded that the greatest benefit would be achieved by transforming HEMeLEF type industries into highefficiency industries. 4. Discussion Most statistical data treat China’s nonferrous metal industries as one industry. Information about specific industry structures, energy consumption, and emissions is lacking. This lack results in an inability by the industries to effectively adjust their structures or to optimize specific procedures, or for the governing authorities to formulate targeted industry policies. Previous studies have primarily focused on one specific nonferrous metal industry, such as the aluminum industry (Ren et al., 2011), or analyzed the entire nonferrous metal industry from a macro perspective. To better understand the characteristics of the 12 nonferrous metal industries, this study proposes corresponding industrial optimization measures based on these classifications. 4.1. Variations in industry emissioneefficiency types

were almost always classified as HEMeHEF types (Table 5), implying a high quality of industrial development and good prospects for future development. We propose that the industries in the leading position should be strengthened and guided towards stable and sustainable development. The aluminum, zinc, and magnesium industries, also key nonferrous metal industries in China, were almost always of the HEMeLEF type, but the development quality of these industries was relatively low. HEMeLEF industries also conduct smelting through electrolysis. The electrolytic process in these industries should be improved or eliminated, their industry position should be gradually reduced, and these industries be transformed into LEMeHEF types. The development of LEMeHEF industries changed significantly during the study period. Although the mercury and magnesium industries were always of the LEMe HEF type, the development of the other LEMeHEF industries was unstable due to existing industrial policy. These industries should be gradually expanded and transformed into HEMeHEF types through the improvement of industrial policies and the establishment of incentive mechanisms to optimize their development. LEMeLEF industries are small scale and operate under stringent environmental management and energy saving requirements. These types of industries should improve their energy efficiency in order to develop into LEMeHEF or HEMeHEF types. Any expansion in their industry scale and/or transformation into HEMeLEF type industries should be strictly prohibited. Meanwhile, because of the improvement in production technologies and the optimization of development policies for nonferrous metal industries, HEMeLEF industries, such as the magnesium industry, show a trend of transforming into the HEMeHEF type. The

To identify variations in emissioneefficiency types between the various metal industries from 2003 to 2010, data were classified according to year and the results are listed in Table 5. Over the eight-year study period, the copper, lead, and nickel industries

Table 4 Emission intensity of nonferrous metal industries in China from 2003 to 2010 (unit: t/104 yuan). Items

2003

2009

2010

Copper Aluminum Lead Zinc Nickel Tin Antimony Magnesium Titanium Mercury Tungsten Molybdenum

5.028 2.240 1.512 1.013 1.125 0.683 0.744 40.057 27.646 21.643 12.093 5.905 5.962 8.629 9.072 3.397 2.300 1.503 0.721 0.728 0.681 10.526 5.656 4.218 1.509 1.270 2.752 2.989 4.043 1.747 1.374 0.698 0.283 0.351 0.474 2.322 0.970 1.105 0.971 0.652 0.464 0.547 3.902 3.039 3.513 2.093 1.575 1.018 1.384 23.720 11.081 14.966 14.487 6.716 6.006 6.019 95.906 84.053 54.908 20.503 4.016 1.060 0.762 0.476 0.122 0.133 0.098 0.057 0.033 0.039 4.096 2.045 1.145 0.401 0.363 1.106 1.516 2.918 2.170 0.637 0.403 0.189 0.067 0.087

2004

2005

2006

2007

2008

0.600 3.802 0.499 1.394 0.339 0.278 0.519 3.531 0.480 0.012 0.586 0.057

Fig. 4. Emissioneefficiency types and industrial added value ratios from 2003 to 2010.

36

C. Shao et al. / Journal of Environmental Management 134 (2014) 30e38

Table 5 Emissioneefficiency type of nonferrous metal industries in China from 2003 to 2010.

2003 2004 2005 2006 2007 2008 2009 2010

HEMeHEF

HEMeLEF

Copper, lead, nickel, magnesium Nickel, tin, antimony, tungsten Copper, lead, nickel, tin Copper, zinc, lead, nickel, tin Copper, zinc, lead, nickel Copper, lead, nickel, antimony Copper, lead, nickel, tin Copper, lead, nickel, magnesium

Aluminum, zinc Tin, antimony, mercury, tungsten, molybdenum Copper, aluminum, lead, zinc, magnesium Mercury, molybdenum Aluminum, zinc, magnesium Mercury, tungsten, molybdenum Aluminum, magnesium Mercury, tungsten, molybdenum Aluminum Mercury, tungsten, molybdenum, tin Aluminum, zinc, magnesium Tin, mercury, molybdenum Aluminum, zinc, magnesium Mercury, molybdenum Aluminum, zinc Tin, mercury, molybdenum

other HEMeLEF industries, including the aluminum and zinc industries, are key targets for future energy savings and emission reductions. Such industries should be gradually transformed into HEMeHEF or LEMeHEF industries through the implementation of cleaner production systems and the formulation of stringent industry emission standards. In the eight-year study period, the antimony and tungsten industries transformed from LEMeHEF to LEMeLEF sectors and therefore require supervision. 4.2. Key industries The four major nonferrous metal industries, i.e., the copper, aluminum, lead, and zinc industries, made great contributions to the industrial added value of the nonferrous metal sector, accounting for an average of 88.75% of the total during the 2003e 2010 period. Meanwhile, these four industries also contributed greatly to the total CO2 emissions, accounting for an average of 96.02% of the total emissions during the 2003e2010 period. In particular, the high CO2 emissions of the magnesium industry and the rapid growth in the demand for titanium makes focus on the emissioneefficiency characteristics of these industries imperative. Their CO2 emission performance and future industrial developments should be carefully examined. (1) Because of the high aluminum production levels and the high energy consumption of the electrolytic aluminum process, the aluminum industry, a stable HEMeLEF industry, made the largest contribution to both CO2 emissions and industrial added value. Meanwhile, the CO2 emissions from the aluminum industry increased dramatically at an annual rate of 14.24% during the study period. The results is basically the same as that accounted by Ren et al. (2011), i.e., 14.53% from 2000 to 2009. Although Wang and Chandler (2010) pointed out that the energy consumption of aluminum production in China had decreased, it remains high. The aluminum industry therefore has the lowest emission efficiency of the 12 nonferrous metal industries, and is the key target for environmental control. According to the “Emergency notice on the curb of the overcapacity and repeated construction of electrolytic aluminum industry to guide the healthy development of industry (China’s Ministry of Industry and Information Technology [2011] NO.177)” and other policies, aluminum electrolysis, the most widely used method for aluminum production in China, is developing very rapidly, thereby resulting in huge greenhouse gas emissions. As one of the largest energy consumers in China, the aluminum industry must be guided towards low-carbon and sustainable development practices, the electrolytic aluminum industry should be phased out, the access threshold for the aluminum industry in terms of energy, resource, and environmental protection should be raised, and the use of hydroelectric power for primary aluminum production should be encouraged.

LEMeHEF

LEMeLEF Titanium Titanium Antimony, titanium Antimony, titanium Antimony, titanium, magnesium Titanium, tungsten Antimony, titanium, tungsten Antimony, titanium, tungsten

(2) As the producer of another widely used metal in China, the copper industry, a HEMeHEF industry, contributed the second highest CO2 emissions and industrial added value. According to the Yearbook of China Nonferrous Metal Industry 2010, to implement relevant requirements in the “Emergency notice on the curb of the overcapacity and repeated construction of electrolytic aluminum industry to guide the healthy development of industry (China’s Ministry of Industry and Information Technology [2011] NO.177)” and other policies, China’s copper industry is promoting the technological transformation of copper smelting enterprises and has eliminated outdated blister copper smelting processes, including the use of blast, electric, and reverberatory furnaces. As a result, the overall energy consumption by copper smelting decreased from 956.95 kg standard coal/t in 2003 to 398.81 kg standard coal/t in 2010, reaching an internationally advanced level. Thus, the low-carbon transformation in the copper industry is a significant achievement. In Guan et al. (2013b) and Wang and Chandler (2010), the authors indicate that owing to the technological advances and the elimination of backward production processes, the energy consumption and CO2 emissions of copper production in China have declined. (3) The lead and zinc industries were also large contributors to CO2 emissions and industrial added value, contributing 8.38% CO2 emissions and 19.96% industrial added value; in terms of carbon emission efficiency, there is room for improvement. Similar results were derived by previous studies. Guan et al. (2013a) indicate that the decrease in energy consumption and CO2 emissions of China’s lead industry was not obvious from 2000 to 2009; room for improvement is therefore huge. Norgate et al. (2007) pointed out that with advanced production technology, the (Gross Energy Requirement (GER) and Global Warming Potential (GWP) of lead and zinc production could be low. According to the Yearbook of China Nonferrous Metal Industry 2010, the elimination of lead smelting by sintering pot-blast furnaces and other outdated production capacities has stabilized the energy consumption and carbon emissions of the zinc and lead industries. From 2003 to 2010, the energy consumption of lead smelting declined from 606.87 kg standard coal/t in 2003 to 421.11 kg standard coal/t in 2010da 44.11% decrease. In 2004, the lead industry transformed from an HEMeLEF to an HEMeHEF industry and continued to develop steadily. Regarding the zinc industry, the energy consumption by zinc electrolysis declined from 1889.59 kg standard coal/t in 2003 to 999.08 kg standard coal/t in 2010dan 89.13% decrease. However, the zinc industry continues to exhibit a high emission state. Great energy saving potential can be realized by the elimination of indigenous zinc smelting and other outdated zinc production processes with high energy consumption, and by strengthening research to improve zinc industry production technology and the zinc smelting short process.

C. Shao et al. / Journal of Environmental Management 134 (2014) 30e38

(4) Because of its huge energy consumption and reliance on outdated electrolysis production technology, the magnesium industry is generally classified as an HEMeLEF industry. Energy consumption by magnesium electrolysis also showed a relatively stable trend during the 2003e2010 periods, around 5000 kg standard coal/t. Therefore, the carbon emissions of magnesium production should be limited, and the magnesium industry be guided to achieve low-carbon and sustainable development by improving the efficiency of electrolysis and by upgrading the energy utilization rate of clean and renewable energy used in electrolysis. (5) The CO2 emissions of the titanium industry, a LEMeLEF industry, increased significantly in the eight-year study period, from 4.57
104 t in 2003 to 47.55
104 t in 2010da growth rate of 940.48%. The overall energy consumption of titanium sponge was consistently high (from 13614.86 kg standard coal/t in 2003e8365.10 kg standard coal/t in 2010) and the range of applications and usage of titanium metal are increasing; thus, low-carbon and sustainable technology development should be given priority. Norgate et al.’s (2007) results show that even in Australia, a country with advanced production technology, the GER of titanium production is 361 (MJ/kg) and the GWP is 35.7 kg CO2/kg, which are both the highest in six kinds of metal industries (copper, aluminum, zinc, lead, titanium and nickel, and titanium), indicating high potential for CO2 emissions. To promote the development of the titanium industry in China, its industrial carbon emissions should be limited, and the industry should be prevented from transforming into an HEMeLEF industry.

5. Conclusion From 2003 to 2010, the economic aspects of the nonferrous metal industry in China developed rapidly, but the growth rate in energy consumption by these industries was still lower than the growth rate of the industrial added value over the same period. Because of the combined effect of technological progress, environmental protection practices for industrial activities, and recycling in nonferrous metal industries, the rate of industrial energy consumption showed a rapidly declining trend. The CO2 emissions of the aluminum industry increased dramatically and also made the largest contribution to the total CO2 emissions. The copper industry contributed the second highest CO2 emissions, but had improved during the study period. The CO2 emissions of the zinc, lead, and magnesium industries increased significantly over the study period; electrolytic magnesium is a major energy consumer and improvements in its production technology have been slow. The CO2 emissions of the other seven nonferrous metal industries were low, but titanium industry showed huge potential for CO2 emissions. Most of the industrial added values from the nonferrous metal industries were from high emission (HEMeLEF type) industries; such industries should be improved and gradually transformed into LEMeHEF types. The copper, aluminum, lead, and zinc industries are key industries for China’s economy, not only in the nonferrous metal sector. These industries should be gradually transformed into LEMeHEF or HEMeHEF types. HEMeHEF industries have highquality operations and good prospects for development. The development of LEMeHEF industries is unstable; such industries should improve their energy efficiency for them to be transformed into LEMeHEF or HEMeHEF types. The LEMeLEF industries are small scale in terms of development and should therefore improve their energy efficiency for them to be transformed into LEMeHEF or HEMeHEF industries.

37

Furthermore, the following policy areas should be targeted: the utilization of nonferrous metal industries; the implementation of technological innovations; the acceleration of industrial technological innovation, optimization, and upgrades; the exertion of efforts to achieve significant results in structural optimization through restructuring and technological upgrades; and the improvement in competitiveness of energy-intensive industries. Finally, as energy consumers, controlling the production and supply of electricity and heat would have a decisive influence on the carbon emissions from the nonferrous metal industries. The proportion of coal in the energy consumption structure should be reduced, and the efficiency of energy use must be improved.

Acknowledgment This study was supported by the key project of national science and technology support plan (No. 2012BAJ24B04-02) and Nature Science Foundation of China (No. 41301579).

References Anderberg, M.R., 1973. Cluster Analysis for Applications (No. OAS-TR-73-9). Office of the Assistant for Study Support Kirtland AFB N MEX. Bao, Y., 2010. Developing low-carbon economy to tackle challenges from climate change. Sino-Global Energy 3, 9e18 (in Chinese). China’s Ministry of Industry and Information Technology, 2011. Emergency Notice on the Curb of the Overcapacity and Repeated Construction of Electrolytic Aluminum Industry to Guide the Healthy Development of Industry. EB\OL [2007-4-20]. Available at: http://www.gov.cn/zwgk/2011-04/20/content_ 1848741.htm (in Chinese). _ Zamfirescu, C., 2011. Sustainable Energy Systems and Applications. Dini˛er, I., Springer, Berlin. Editorial Committee of Yearbook of China Nonferrous Metal Industry, 2004e2011. Yearbook of China Nonferrous Metal Industry. Nonferrous Metal Industry Yearbook Editorial Press, Beijing (in Chinese). Energy Information Administration, 2009. Voluntary Reporting of Greenhouse Gasses Program. EB/OL [2009-08-21]．Available at: http://www.eia.gov/oiaf/ 1605/coefficients.html%20-%20tbl5%5b23%5d. Guan, Y., Shao, C., Tian, X., et al., 2013a. Analysis of carbon footprint of Chinese lead industry during 2000 to 2009 and control strategy study. Environ. Pollut. Control 35 (2), 99e103 (in Chinese). Guan, Y., Shao, C., Tian, X., et al., 2013b. Carbon footprint attributed to aluminum substitution for copper in the Chinese indoor air conditioner industry. J. Clean. Prod. 51, 126e132. Guinee, J., Heijuncs, R., Kleijn, R., et al., 2006. Human and ecological life cycle tools for the integrated assessment of systems (HELLAS). Int. J. Life. Cycly. Assess. 11, 19e28. IEA, 2009. World Energy Outlook 2007-China and India Insights. Organisation for Economic Co-operation and Development, Paris. Ijima, K., Harada, K., 2001. Ecomaterials selection. Calculation of CO2, SOx, NOx emission form nonferrous metal production process based on economic statistics. J. Jpn. I. Met. 65 (7), 571e580. International Aluminum Institute, 2008. Life Cycle Assessment of Aluminum: Inventory Data for the Primary Aluminum Industry-year 2005 Update (London). IPCC, 2006. The 2006 IPCC Guidelines for National Greenhouse Gas Inventories (2006 Guidelines). IGES, Hayama. IPCC, 2007. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge and New York. Itsubo, N., Yamamoto, R., 1999. Application of life cycle assessment to manufacturing of nonferrous metals. J. Jpn. I. Met. 63, 208e214. Kaufman, L., Rousseeuw, P.J., 2009. Finding Groups in Data: an Introduction to Cluster Analysis. Wiley. com, Hoboken, US. Kuckshinrichs, W., Zapp, P., Poganietz, W., 2007. CO2 emissions of global metalindustries: the case of copper. Appl. Energ. 84, 842e852. Li, H., Ma, L., Qi, Y., 2011. Comparison of climate change policy processes between China and USA. China Popul. Resour. Environ. 7, 51e56 (in Chinese). National Bureau of Statistics of China, National Development and Reform Commission, 2001e2011. China Energy Statistical Yearbook. China Statistics Press, Beijing (in Chinese). National Bureau of Statistics of China, 2012. China Statistical Yearbooks. China Statistics Press, Beijing (in Chinese). Norgate, T., Oct. 2001. A Comparative Life Cycle Assessment of Copper Production Processes. CSIRO Report DMR-1768. Available at: http://www.intec. com.au/. Norgate, T., Haque, N., 2012. Using life cycle assessment to evaluate some environmental impacts of gold production. J. Clean. Prod. 29, 50e63.

38

C. Shao et al. / Journal of Environmental Management 134 (2014) 30e38

Norgate, T., Jahanshahi, S., Rankin, W., 2007. Assessing the environmental impact of metal production processes. J. Clean. Prod. 15, 838e848. Ren, X., Tian, X., Ju, M., et al., 2011. Dynamic study of carbon footprint of Chinese aluminum industry based on life cycle assessment during the period of 2000e 2009. J. Saf. Environ. 11 (1), 121e126 (in Chinese).

United States Geological Survey, 2011. Data Series 140. Available at: http://minerals. usgs.gov/ds/2005/140/. Wang, Y., Chandler, W., 2010. The Chinese nonferrous metals industry e energy use and CO2 emissions. Energ. Policy 38 (11), 6475e6484.