Scholarly article on topic 'Embodied Energy Account of Chinese Economy 2002'

Embodied Energy Account of Chinese Economy 2002 Academic research paper on "Materials engineering"

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Abstract of research paper on Materials engineering, author of scientific article — M.M. Jiang, B. Chen, S.Y. Zhou

Abstract In this research, input-output (I-O) model was used to calculate the embodied (direct plus indirect) energy consumption of the Chinese 42 major sectors based on the estimation of the direct energy inputs to the Chinese economy in 2002. Several indicators, involving the embodied energy intensity, imported energy dependent index, and energy balance of trade, were provided to analyze the energy basement of the current Chinese industry. This study also explored the Chinese energy use structure for the added value and final use in 2002, and investigated the disparity in energy use between the rural consumption and the urban consumption. The cluster analysis was employed to group these sectors according to their similarities in embodied energy intensity, imported energy dependency, and energy use structure of final use. Conclusion shows that the energy industries held the highest energy intensities in China while most light industrial sectors, hi-tech sectors and various service sectors enjoyed the lowest energy intensities. And the petroleum associated sectors are most in degree for the imported-energy dependency in 2002, as a great contrast to the coal-associated industries. This was further explored through the Chinese energy balance of trade in 2002, which reveals that the oil consumed sectors encountered serious embodied energy deficits, but the sectors with coal as major fuel held embodied energy surplus.

Academic research paper on topic "Embodied Energy Account of Chinese Economy 2002"

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•• ScienceDirect Procedia

Environmental Sciences

Procedia Environmental Sciences 5 (2011) 184-198

2010 International workshop from the International Congress on Environmental Modeling and

Software (iEMSs2010)

Embodied Energy Account of Chinese Economy 2002 Jiang, M.M.a,b*, Chen, Ba' Zhou,S.Y.b

a State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing

100875, China

b Beijing Development Area Corporate Ltd., Low-carbon Center, Beijing 100176, China

Abstract

In this research, input-output (I-O) model was used to calculate the embodied (direct plus indirect) energy consumption of the Chinese 42 major sectors based on the estimation of the direct energy inputs to the Chinese economy in 2002. Several indicators, involving the embodied energy intensity, imported energy dependent index, and energy balance of trade, were provided to analyze the energy basement of the current Chinese industry. This study also explored the Chinese energy use structure for the added value and final use in 2002, and investigated the disparity in energy use between the rural consumption and the urban consumption. The cluster analysis was employed to group these sectors according to their similarities in embodied energy intensity, imported energy dependency, and energy use structure of final use. Conclusion shows that the energy industries held the highest energy intensities in China while most light industrial sectors, hi-tech sectors and various service sectors enjoyed the lowest energy intensities. And the petroleum associated sectors are most in degree for the imported-energy dependency in 2002, as a great contrast to the coal-associated industries. This was further explored through the Chinese energy balance of trade in 2002, which reveals that the oil consumed sectors encountered serious embodied energy deficits, but the sectors with coal as major fuel held embodied energy surplus.

© 2010 Published by Elsevier Ltd.

Keywords: embodied energy, Chinese economy, I-O analysis, 42 sectors Introduction

ELSEVIER

* Corresponding author. Tel.: +86 10 67872115; fax: +86 10 67871204. E-mail address: jiangmeiming@hotmail.com.

1878-0296 © 2011 Published by Elsevier doi:10.1016/j.proenv.2011.03.066

Introduction

The potential for the other "energy crisis" has never been higher. As one of the most energy consumer in the world, China was confronted with unprecedented challenge because of the great dependence on energy, especially on coal and crude oil, which consequently brought not only a great pressures for the Chinese economy, but also a great deal of environmental impacts. Especially in the context of limiting of greenhouse gases emission, energy conservation and energy structure adjustment is increasingly important not only for China itself, but also for the global sustainable development.

Although energy conservation and associated issues has been formulated into law (Law of the People's Republic of China on Conserving Energy) as early as ten years ago with improvement in 2007 to adapt the current situation, the implementation of the law are not optimistic.

As a crucial and necessary step for energy administration, energy based analysis provides quantitative results and comprehensive information about how and where the energy use in economic system, thus made it possible for administritors to take timely actions and treatments to improve the mode of energy use pointedly.

Energy-based analyses originated from the middle 19th with the presentation of the first law of thermodynamics [1]. The Energy Crisis of the 1970s brought the rapidly-expanding study of the energy costs of production processes, encompassing foods and agriculture [2-4], materials [5], petrochemicals and products [6-7] and their importance for policy making [8-9].

Embodied energy analysis, as one of important energy analysis, is the process of determining the energy required directly and indirectly to allow a system (usually an economic system) to produce a specified good or service [10], which explicitly and rigorously calculates indirect effects [8]. For the different understandings of the scale and scope of application and the type of energy embodied, there are many different methodologies associated with embodied energy analysis [11-13].

Two major approaches are available for the embodied energy accounting; one is Process Chain Analysis (PCA), which reveals the total energy requirements of a product or service through aggregating the energy necessary involved in its life cycle [14-18]. And the other is Input-Output Analysis (IOA), which grew out of Wassily Leontiefs input-output model [19-20] and adapted by Hannon[21] to tabulate the total direct and indirect energy requirements (the 'energy intensity') for each output made by the concerned system [8, 22-24]. Compared with PCA, IOA can efficaciously provide a panorama of both direct and indirect energy flows throughout the entire economic system. Since modern industrial systems are complex interconnected system with many inputs and outputs, IOA was not only used to analyze the specific industry, such as building industry [25-27], steel industry [28], power-generation [29] and international trade [30, 31], but also to evaluate the economic network in national and regional scales [32-38]. Also, the IOA was satisfied some researchers' needs to investigate the relationship between the greenhouse gas emission and the embodied energy for the recent concerns about the global climate change [37, 39-40].

In this research, the I-O model in economic analysis was used to calculate the direct and indirect (embodied) energy consumption of the Chinese major sectors based on various estimates of the distribution of direct energy inputs to the sectors for the year 2002. The results of this analysis may provide insights into quantitative understanding of the base of the Chinese economy and the current energetic structure.

Methodology

2.1 I-O Table of Chinese economy

As one of the approaches to calculate embodied energy, I-O analysis based on input-output table reflects the sources of the input into and the utilization of the output from production by various industries of the national economy, constituting an important part of the new national economic accounting system. It can be used to reveal the interrelated and manually dependent economic and technological relations between industries in quantitative terms.

Generally speaking, the system boundary of accounting is the national or regional borders. In the paper, the whole country of China, except the area of Hong Kong, Taiwan and Macao, is chosen as the boundary of the analysis. And one year is taken as the time cycle for the system analysis in this paper.

In China, up to now, 7 I-O tables have been available for 1987, 1990, 1992, 1995, 1997, 2000 and 2002. The 2002 Input-Output Tables of China is the forth benchmark table since 1987, 1992 and 1997 through the large scale input-output census across the country [41, 42]. There are three edits for this table (2002) separately dividing the economy into 17 industries [43], 42 industries and 122 industries [41].

The sources and data applied in this research come from the 2002 Input-Output Table of China with 42 sectors as shown in Table 1.

Table 1 2002 Input-output Tables of China

(At current producers' prices) 10 thousand RMB

OUTPUT

Intermediate use

Final use

Final consumption

Household consumption

Gross capital formation

Agriculture

Public administration and other sectors

Total intemediate use

Compensatio n of employees

Net taxes on production

Depreciation of fixed capital

Operating surplus

Total value surplus

Total inputs

This 2002 I-O table of China consists of three parts, normally called Quadrant I, Quadrant II, and Quadrant III, and adopts the new classification criterion of industry in the national economy [44]. The three quadrants of the I-O table comprehensively and systematically reflect the relations between different industries from production to final

The 42 sectors involves agriculture, mining, manufacturing, scrap and waste, electricity, gas and water production and supply, construction, transport and warehouse, post, wholesale and retail trade services, food serving services, and other services, the details of which are numbered from No.1 to No.42 as shown in Table 2 [41]. And the money unit is the 2002 RMB.

Table 2 The numbered 42 Chinese major sectors.

No. Sector No. Sector

1 Agriculture, Forestry, Animal husbandry & Fishery 22 Scrap and waste

2 Mining and Washing of coal 23 Electricity, steam and hot water production and supply

3 Extraction of petroleum and natural gas 24 Gas production and supply

4 Metal ore mining 25 Water production and supply

5 Non-metal minerals mining 26 Construction

6 Manufacture of food products and tobacco processing 27 Transport and storage

7 Textiles 28 Post services

8 Wearing apparel, leather, fur, down and related products 29 Telecommunication, Computer services and Software

9 Sawmills and furniture 30 Wholesale and retail trade services

10 Paper and products, printing and record medium reproduction 31 Accommodation and food serving services

11 Petroleum processing, coking and nuclear fuel processing 32 Finance and insurance

12 Chemicals 33 Real estate

13 Nonmetallic mineral products 34 Rental and business services

14 Metal smelting and pressing 35 Travel agency, tour operator and tourist guide services

15 Metal products 36 Scientific research

16 General and special purpose machinery 37 Professional, scientific and technical services

17 Transport equipment 38 Other social services

18 Electric equipment and machinery 39 Educational services

19 Electronic and telecommunication equipment 40 Health, social security and welfare

20 Instruments, meters, cultural and office machinery 41 Cultural, sporting and recreational services

21 Other manufacturing products 42 Public administration and other sectors

2.2 Calculation of total energy input

For calculating embodied energy through the I-O analysis, a set of energy balance equations (one for each sector) should be defined firstly, then the resulting set of simultaneous linear equations could be solved for the energy intensity coefficient vector e, which is the energy required directly and indirectly to produce a unit commodity flow [33].

Following the research of Costanza [33-35], the embodied energy involved in this paper are coal, oil, natural gas, nuclear fuel, and some renewable energy, such as hydraulic power, wind power, tidal power and solar energy, used for generating electricity and supplying heat. However, the part of solar energy, which are transferred and collected by vegetables through photosynthesis, is not considered here.

The direct energy input from environment respectively flows into three sectors: Mining and Washing of coal, Extraction of petroleum and natural gas, Electricity, steam and hot water production and supply.

The direct energy consumption of the Chinese economy in 2002 is the sum of all those consumed energy mentioned above, most of which can be calculated through the equation as follows:

EEi = HVi (E , + NIM i)

Where EE, is the direct consumption of some specific energy, HV, is the heat value of the energy, Et is the exploitation quantity, and NIMi is the net import volume.

Hydraulic power is generally not imported and its exploitation quantity can be got directly through the quotient of the quantity of generating hydropower and the average unit efficiency (90% here). And the calculation of nuclear energy is just alike.

2.3 Calculation of Embodied Energy Intensity

Fig. 1(a) is an I-O diagram based on a traditional I-O table, of which the box in dotted line represents the concerned system, the arrow with mark Xj represents the total yield from the sector j, x'j and x"ij represent the intermediate use separately from within the system and outside the system, the arrow in the box with mark x'j is the output from an internal sector i to the user, sector j, and the arrow with x",j means the output from an external sector i to the user, sector j. This diagram reveals how goods or money flow among different sectors within the concerned system, but it not considers the resources input directly from environment because an I-O table includes only the resources that have been brought into the industrial sectors.

Fig. 1 I-O diagrams with intermediate use from different sources

(a) traditional I-O diagram; (b) modified I-O diagram with direct energy input

In Fig. 1 (b), a modified diagram which includes the direct environmental input is presented. Compared with the Fig.1 (a), it is added a new arrow EE j, representing the direct resource input from environment to the concerned sector j. Only with the EEj, the environmental contribution can be accounted and evaluated in the I-O analysis.

In this paper, of the various environmental resources, only energy mentioned above are considered, so EE j in the paper represents the energy input directly from environment to the sector j. And the I-O technique for calculating embodied energy is a distribution process during which energy from outside is distributed to different sectors and commodities based on the I-O table. Therefore, there would be no double accounting since the sum of the yield's embodied energy must be equal to the total input energy.

In Fig. 1, x'j and x"ij represent the outputs, respectively from within the system and from outside, to the sector j. For a national system as in the paper, it means consumed goods and services which came from local production and from exporters, respectively.

Generally speaking, for two different systems, the embodied energy required to produce a unit commodity flow of the same kind will totally different. This also means when the embodied energy intensity is calculated as shown in Fig.2, x'j and x"ij from different sources should correspond to different intensities as Sj and j According to the energy balances in input-output table, there are some equations as follows:

EE¡ Zs x'ij SjXj

Sector (Product) j

Fig.2 Energy balance diagram of Sector j with intermediate use from different sources n n

EEj= sjxj ~^Lsix'ij - Z^xj' (2)

i—1 i—1

Where EEj is the direct energy consumption of the sector j, sj is the embodied energy intensity (EEI) per unit of the yield x, and Q is the embodied energy intensity (EEI) per unit of the external input x"ij. The equation 1 can be transferred as vector equation as follows:

EE + &" = e(x - x ), (3)

Where EE is the vector of the local direct input, £x" is the vector of the indirect energy input from outside, s represents the vector of the embodied energy intensity (EEI), x is the diagonal matrix of the total yield, and x represents the intermediate I-O matrix.

If the nonhomogeneous linear equation have solutions,

e = (EE + )(x - x')o (4)

Considering the sources of different intermediate use have not been distinguished in the current I-O table in the national level, so based on the table the calculation can be carried out only under the hypothesis that the same kind of goods or services from different sources holds the same embodied energy intensity (EEI). Therefore, in our calculation, the flow x'j and x"j in Fig. 1 can be combined into xij, as shown in Fig 3.

Sector (Product) j XJ EE, Sector (Product) j Xj

(a) (b)

Fig.3 I-O diagram with the source of intermediate use not considered

(a) Traditional I-O diagram;(b) Modified I-O diagram with direct energy input

The direct energy consumption of the sector j, EEj, thus can be calculated based on Fig.4 as follows:

EEj =sjxj ~Yjsixij ' (5)

Where xj is still the yield of the sector j, Sj is the embodied energy intensity (EEI) per unit yield of x, x, means the output from any other sector i to the sector j, and et is the embodied energy intensity per unit of x,.

EEj Sector (Product) j SjXj

Fig.4 Energy balance diagram of Sector j with the source of intermediate use not considered

The equation 4 can be transferred as vector equation as follows: EE = s(x - x), (6)

Where EE is the vector of the local direct input, s represents the vector of the embodied energy intensity (EEI), x is the diagonal matrix of the total yield, and x represents the intermediate I-O matrix. If the nonhomogeneous linear equation have solutions,

s = EE(x - x)_1 o (7)

If y is the final use matrix, the embodied energy of the final use vector, FU, can be calculated as follows: FU = ye

All the calculations discussed above are based on the assumption that the nonhomogeneous linear equations have solutions, although there are the possibilities of no solutions, myriads of solutions, or negative value of solution, but all these solutions have no physical meanings.

Direct Environmental Energy Input of Chinese Economy 2002

For calculating the embodied energy intensity of the final use, the direct energy consumption from environment, illustrated as EEj in Fig.4, should be accounted firstly as shown in Table 2, which considers the important energy input, involving coal, oil, natural gas, and hydraulic power, to three energy associated sectors of the Chinese economy in 2002.

Table.2 China direct energy input from environment, 2002.

Coal mining Petroleum and natural Electricity, steam

and dressing gas extraction production and supply

Coal ( J) 2.76*1019 0 0 0

Oil (J) 0 9.58*1 018 0 0

Natural gas ( J) 0 0 1.16*1 018 0

Hydraulic power ( J) 0 0 1.12*101S

Total input ( J) 2.76* 1019 1.07*1019 1.12*101S

Results

4.1 Embodied energy intensity analysis

4.1.1 Energy intensity for the Chinese 42 sectors in 2002

Embodied energy intensities represent a set of measurable coefficients of the direct and indirect energy required for the formation of a unit of produced goods or services. With the method in section 2.3, the embodied energy intensities of the Chinese 42 major sectors are calculated and illustrated as shown in Fig.5. Furthermore, according to the source of energy, i.e., whether the energy came from abroad or from within the country, the intensity of any sector is divided into two parts, the embodied imported energy intensity and the embodied internal energy intensity as revealed in Fig.5. In embodied energy analysis, these coefficients are of fundamental importance.

Embodied energy intensity (J/10E4 RMB)

Fig. 5 Embodied energy intensity of Chinese 42 sectors, 2002 ( J/104 Y)

For a sector, the higher the embodied energy intensity, the more the energy consumed for supplying a unit of goods or services. With their intensities revealed in Fig.5, the concerned sectors can be divided into three categories.

The first category includes the five energy associated sectors, i.e., Mining and Washing of coal (Sector 2), Extraction of petroleum and natural gas (Sector 3), Petroleum processing, coking and nuclear fuel processing (Sector 11), Electricity, steam and hot water production and supply (Sector 23), and Gas production and supply (Sector 24), their energy intensities are the highest of the three, vary from 1.6*1010 J to 7.8*1010 J per thousand Yuan, nearly ten times higher than the sectors belong to the other two categories.

The second category involves some heavy industrial sectors and energy-dependent industries, such as Metal ore mining (Sector 4), Nonmetallic mineral products (Sector 13), Metal smelting and pressing (Sector 14), Transport and storage (Sector 27) and Construction (Sector 26), with energy intensities vary from 3.5*109 J to 7.3*109 J per thousand Yuan.

And the category with the lowest energy intensities includes mainly light industrial sectors, hi-tech sectors and various service sectors, and most of their energy intensities are lower than 3.0*109 J per thousand Yuan, which is assimilate with the conclusion got by Costanza [33].

4.1.2 Imported energy dependent index

The imported energy dependent index is the quotient of the embodied imported energy intensity to the embodied energy intensity. It means, of the total energy use to producing a unit of goods or services for a sector, what proportion is came from imports. This index reveals the degree of dependency for a sector on the imported energy. The greater the index, the deeper the sector depend on the imported energy. Of the major Chinese sectors, there are 19 sectors holding the index no less than 0.1, which means that, for these sectors, at least 10% energy directly or indirectly came from imported energy to produce goods or services valuing ten thousand Yuan.

Of these 19 sectors, the petroleum associated sectors, including Extraction of petroleum and natural gas (Sector 3) and Petroleum processing, coking and nuclear fuel processing (Sector 11) are most in degree for the imported-energy dependency with the index as high as 0.25 and 0.22, respectively in 2002.

The least imported energy dependent sector in China is the coal-associated sectors, such as Mining and Washing of coal (Sector 2), Electricity, steam and hot water production and supply (Sector 23), and Gas production and supply, which hold the index as 0.01, 0.03 and 0.05, respectively in 2002.

0 |.................................................................

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 0.24 0.26 Imported energy dependent index

Fig.6. Imported energy dependent index

4.2 Value added

Value added in I-O table refers to the additional value of a commodity over the cost of commodities used to produce it from the previous stage of production. As to the embodied energy analysis, value added means how much energy involved directly and indirectly associated with the created additional value. As shown in Fig.7, Construction (Sector 26) is the sector which involved the most energy of 1.14x1019 J associated with the created additional value of 2.63*1012 Yuan in 2002, and Mining and Washing of coal (Sector 2) just next to the Construction with energy as much as 6.02x1018 J for the additional value of 7.79x1010 Yuan in 2002, which means that, to create the GDP of 6.39%, it will consumed energy around14.55% of the total energy use in this sector. The sector of Agriculture, Forestry, Animal husbandry and Fishery (Sector 1), however, created GDP of 1.22*1012 Yuan in 2002 with embodied energy about 2.31*1018 J, that is, creating about 10.04% of the GDP on about 5.59% of the total energy

1.2x10H 1.0x1019-8.0x1018 6.0x1018

tu u u nj a)

E? a c CD

3x10-2x1018 1x1018-| 0

-1x1018

lu -2x10

■ i i i i i i

^t-LOCO OD O) O

IXUXl.tl

1I I 11 III I I I I I I I ITI IT I I I I I I I I II II I I

-T-T-T-T-T-T-T-T-C^tNCNINININC^f^C^r^MCOCOCOCOCOnCOCOCOTfTf'i

Fig.7 Embodied energy of value added for 42 Chinese major sectors in 2002

Of the concerned 42 Chinese sectors, the sectors whose energy use taking more than 4.0% of the total include only six, that is, coal mining (14.55%), agriculture (5.59%), general machinery production (4.61%), public administration (4.48%), transport and storage (4.33%) and food production (4.33%).

It worthwhile to mention that the value added of the sector 3, 4, 11, 14 as shown in Fig.7, i.e., Extraction of petroleum and natural gas, Metal ore mining, Petroleum processing, coking and nuclear fuel processing, and Metal smelting and pressing, are negative, indicating there were "embodied energy deficits" for the four sectors and most of their energy involved were imported from abroad.

4.3 Balance of trade

The difference of imports and exports, often called balance trade in economy, of the Chinese 42 sectors is shown in Fig.8 with (a) indicating the difference of money flow and (b) the energy flow. Generally speaking, if imports are more than exports, it is trade deficit (negative in Fig.8) and often thought unfavorable balance of trade. Otherwise, it is trade surplus (positive in Fig.8) and favorable.

As has been mentioned in the section 2, all our calculation is based on the premise that, for the products with the same quantity and quality, the embodied energy intensities are the same whatever they are imported or produced in local. With this premise, the embodied energy associated with the total Chinese imports is 1.61*1019 J, 21.0% higher than that of the exports although in the same year the trade surplus is as high as 30.4 billion dollar. This result

reveals an unbalance situation existed in the present foreign trade caused by the different product structure of the imports and exports. That is, most imported products came from energy-intensive industry, such as fuels, finished materials and machines, while a great deal of exported products came from light industries with less energy consumption [45]. This also proved that the balance trade in RMB unit cannot reveal the potential situation of energy flow in foreign trade. As shown in Fig.8, the apparent inconsistencies exist between the (a) and (b). Take the sector 30 (Wholesale and retail trade services) for another example, small commodity manufacture as a traditional labor-intensive industry, is a main way to create foreign exchange for China with trade surplus of 2.53*10n Yuan in 2002, listing the first of all the mentioned sectors as shown in Fig.8 (a). However, as to the energy analysis, the embodied energy surplus of this sector is only 5.02x1017 J, listing the fourth with value not much higher than that in other sectors.

As revealed by the Fig.8 (b), the oil consumed sectors, involving Sector 3 (Extraction of petroleum, and natural gas), Sector 11 (Petroleum processing, coking and nuclear fuel processing), sector 12 (Chemicals), and sector 14 (Metal smelting and pressing) encountered serious embodied energy deficits varying from 6.59*1017 J to 3.62x1018 J in 2002, indicating that these sectors are of great dependent on the imported oil during their production process, compared to the Sector 2 (coal-dependent sectors, such as Mining and Washing of coal) and Sector 23 (Electricity, steam and hot water production and supply), which held embodied energy surplus for their main use of coal. The productive department of most mechanical equipments, involving Sector 16 (General and special purpose machinery), Sector 17 (Transport equipment), Sector 19 (Electronic and telecommunication equipment), and Sector 20 (Instruments, meters, cultural and office machinery) also had great embodied energy deficit since these sectors depended on imported energy directly and indirectly.

m 1x107

15 o 0

-1x107

-2x107

Exports minus imports for money flow

18\./ 21 24 27 30 ' 33 36 Major sectors in China

IxlO1 0

-1x101! -3.5X1011 -4.0X1011

I Exports minus imports for embodied energy

18 21 24 27 30 33 36 Major sectors in China

Fig.8 Differences of imports and exports for Chinese 42 sectors in 2002.

4.4 Final use

Fig.9 illustrates the division of energy in different final use, which reveals how the energy divided among different ending including rural and urban consumption, government consumption, gross fixed formation, change in inventories and exports.

Gross fixed capital formation 1.76E19J3225%)

Change in inventories 1.75E18J(3.21%)

Government consul 4.45E18J(8.15%) !

[ports

I3E19J(24.37%)

Urban consumption 1.27E19J(23.27%)

areonsumption 4.78E18J(8.76%)

Fig.9 Division of energy for final use

Of the total embodied energy associated with the final use, 23.3% consumed by the urban and township residents with population 5.02x108, while only 2.5% by the rural residents with population 7.82x108. That means the average embodied energy per person in urban and township reach 2.54x1010 J, which is about 4.2 times of that consumed by the people in rural area with only 6.11 x109 J per person. This can be further investigated in details as Fig.10, which presents the embodied energy of the average per capita consumption from all the sectors. The results shows that, except the sector 4, 22, 26, 36, 37 and 42 which provided no products for the household consumption directly, embodied energy of urban consumption was far more than that of the rural consumption for all sectors, indicating that residents in urban area enjoyed much better treatments and welfare benefits.

For example, the sector 35, the Travel agency, tour operator and tourist guide services, as the most striking of all, provides products with embodied energy as high as 1.41x108 J per person for people in urban area, 24.37 times of that for those in rural area with 5.77x106 J per person, intimating that travelling as a popular form of entertainment is still enjoyed by the urban residents. Other sectors, such as the sector 16, 29, 25 and 8, also supplied residents in urban area products with embodied energy 9.68, 9.31, 8.95 and 8.35 times, respectively, than those in rural area.

3.50E+009 -,

S3 2.50E+009

§ 2.00E+009-

H 1.50E+009-

g 1.00E+009

if 5.00E+008-

E= (D TD

€ 0.00E+000

Average urban consumption per capita Average rural consumption per capita

Sectors

Fig.10 Comparison of the urban consumption and rural consumption

The part gross fixed formation and change in inventories are generally called gross capital formation, which held energy of 1.93x1Q19 J and took 35.4% of the total final use in 2002 as shown in Fig.9. And exports, taking

24.4% of the final use, act an important role in Chinese economy and have been proved consuming a great deal of energy among different ending mentioned above.

4.5 Hierarchical cluster analysis

To further investigate the energy use structure of the current Chinese industry, cluster analysis was employed to group the concerned sectors according to their similarities. Some variables, including embodied internal energy intensity, embodied imported energy intensity, rural consumption, urban consumption, government consumption, gross fixed capital formation, change in inventories and exports, were selected here and normalized as a data set for the hierarchical agglomerative cluster analysis (CA). Using a kind of statistical analysis software, Statistics Package for Social Science (SPSS), these sectors were classified, with the methods of Between-groups linkage, into groups according to their similarity through measuring their Euclidean distances. And the results are presented in Fig.11.

ÄÄÄÄÄ*ÄÄÄ*ÄÄÄÄAÄÄÄ*HIERARCHICAL CLUST EE ANALYSIS*******************

Dendrogram using Average Linkage (Between Groups)

Rescaled Distance Cluster Combine

Secto L Nunn

Secto 25 25

Secto 28 28

Secto 35 35

Secto 4 4

Secto 5 5

Secto 22 22

Secto 29 29

Secto 32 32

Secto 41 41

Secto 36 3 6

Secto 37 37

Secto ID 10

Secto 21 21

Secto 34 34

Secto 14 14

Secto 17 17

Secto 15 15

Secto 20 20

Secto 16 16

Secto 31 31

Secto 38 38

Secto 13 13

Secto Secto 33 24 33 24

Secto 18 18

Secto 8 8

Secto 27 27

Secto 30 30

Secto 39 39

Secto 40 40

Secto 12 12

Secto 19 19

Secto 3 3

Secto 11 11

Secto 1 1

Secto 23 23

Secto 42 42

Secto 26 2 6

Secto 2 2

Fig.11. Results of the hierarchical cluster analysis

Revealed by the Fig.11, the groups divided by the 42 sectors showed multiple levels with many sub-grade clusters according to their similarity in energy use structure, energy intensity and imported energy dependency.

For example, the sector 2, Mining and Washing of coal, with the highest energy intensity of the total sectors, was separated from the others as a group, providing coal for the other industrial sectors. And the sector 26,

Construction, as a sector creating the most capital assets and also spending the most energy in their production process, was also divided into a separate group, though closer to other sectors than the sector 2.

Sectors of food supply, including agriculture industry (sector 1) and food production (sector 6) were a kind, which was closer to the sector 23, Electricity, steam and hot water production and supply, since most of the final use in these sectors was associated with the household consumption. Petroleum associated sectors, the sector 3 and 11, formed a group with high energy intensities and the greatest dependency on the imported energy. Most service industries and a few development sectors (from the top sector 25 downward to the sector 37) were grouped as a kind, which characterized by the moderate dependency on the imported energy, and relatively low both in energy intensity and in final used energy. This group was closer in distance to the next group, which included 6 manufacturing sectors from the sector 9 to 17, with the similar moderate imported energy dependency, but higher energy intensity.

Conclusion

This research revealed the embodied energy consumption of the Chinese 42 major sectors through the I-O model and analyzed the basic information of energy flows in the Chinese economic structure, providing insights into quantitative understanding of the base of the Chinese economy.

With the indicator of embodied energy intensity, the direct and indirect energy use to form a unit of goods or services for the specific sector was revealed, which shows that the energy industries held the highest energy intensities while most light industrial sectors, hi-tech sectors and various service sectors enjoyed the lowest energy intensities.

Conclusion shows that the coal mining industry itself in China is one of the largest energy consuming sectors, therefore, improving the energy use efficiency of this sector will offers a chance to reduce the demand for primary energy without adversely affecting the rest of the industrial system. The research shows that the construction sector is crucial in national economy because the most embodied energy was involved during its creation of value, which means once the development speed of the construction sector becomes slower, most of the Chinese sectors will be affected.

From the calculation of the imported energy dependent index, the conclusion showed that the petroleum associated sectors are most in degree for the imported-energy dependency with the index more than 0.2 in 2002. And the least imported energy dependent sector in China is the coal-associated sectors, holding the index less than 0.05. This was further explored through the Chinese energy balance of trade in 2002, which reveals that the oil consumed sectors encountered serious embodied energy deficits, but the sectors with coal as major fuel held embodied energy surplus.

Acknowledgement

This study has been supported by the National Key Program for Basic Research (973 Program, Grants no. 2006CB403304 and 2005CB724204), and in part by the National Natural Science Foundation of China (Grant no.40801233) and Beijing Natural Science Foundation (Grant no. 8061002).

Reference

[1] Martinez-Alier, J. Ecological Economics: Energy Environment and Society, Basil Blackwell Ltd, Oxford, 1990.

[2] Leach, G. Slesser, M. Energy equivalents of network inputs to the food production process (Strathclyde University Report, UK) , 1973.

[3] Leach, G. Energy and Food Production, Guildford, Surrey, UK: IPC Science and Technology Press Ltd, 1976.

[4] Pimentel, D., Pimentel, M. Food, Energy and Society. Edward Arnold, London., 1979.

[5] Bravard, J.C., Portal, C. Energy requirements in the production of metals. Oak Ridge Laboratory Report, USA, 1971.

[6] Smith, H. 'Cumulative energy requirements of some products of the chemical industry' Transactions 20, Section E, World Energy Conference ,1969.

[7] Chapman, P.F. The energy costs of producing copper and aluminium from primary sources. Open University Report ERG 001, UK, 1973.

[8] Bullard, C.W., Herendeen, R.A. The energy cost of goods and services. Energy Policy 1975; 3(4), 268-278.

[9] Mirowski, P. More Heat than Light: Economics as Social Physics, Physics as Nature's Economics, Historical Perspectives on Modern Economics, Cambridge University Press, Cambridge, 1999.

[10] International Federation of Institutes for Advanced Study (IFIAS) Energy Analysis Workshop reptort. No. 6. Int. Fed. of Inst. for Adv. Stud., Stockholm, Sweeden, 1974.

[11] Chen, G.Q., Jiang, M.M., Chen, B., Yang, Z.F., Lin, C. Emergy analysis of Chinese agriculture. Agriculture, Ecosystems and Environment 2006; 115(1-4), 161-173.

[12] Chen, B., Chen, G.Q., Yang, Z.F., Jiang, M.M. Ecological footprint accounting for energy and resource in China. Energy Policy 2007; 35(3), 1599-1609.

[13] Jiang, M.M., Chen, B., Zhou, J.B., Tao, F.R., Li, Z., Yang, Z.F., Chen, G.Q. Emergy account for biomass resource exploitation by agriculture in China, Energy Policy 2007; 35(9), 4704-4719.

[14] Chapman, P.F. Energy costs: a review of methods. Energy Policy 1974; 2(2), 91-103.

[15] Debnath, A., Singh, S.V., Singh, Y.P. Comparative assessment of energy requirements for different types of residential buildings in India, Energy and Buildings 1995; 23, 141-146.

[16] Venkatarama-Reddy B.V., Jagadish K.S. Embodied energy of common and alternative building materials and technologies. Energy and Buildings 2003; 35, 129-137.

[17] Chen, B., Chen, G.Q. Ecological footprint accounting based on emergy—A case study of the Chinese society. Ecological Modelling 2006; 198(1-2), 161-173.

[18] Wang, R., Cai, Z. An ecological assessment of the vernacular architecture and of its embodied energy in Yunnan, China. Building and Environment 2006; 41, (5), 687-697.

[19] Leontief, W. Quantitative input-output relations in the economic system. Review of Economic Statistics 1936; 18, 105-125.

[20] Leontief, W. Input-Output Economics, Oxford University Press, New York, 1966.

[21] Hannon, B. The Structure of ecosystems. Journal of Theoretical Biology 1973; 41, 535-546.

[22] Treloar, G.J. Extracting Embodied Energy Paths from Input-Output Tables: Towards an Input-Output-based Hybrid Energy Analysis Method, Economic Systems Research 1997; 9(4), 375- 391.

[23] Treloar, G.J. A comprehensive embodied energy analysis framework, Ph. D. Dissertation, Deakin University, Australia, 1998.

[24] Tennenbaum, S.E. Network Energy Expenditures for Subsystem Production, MS Thesis. Gainesville, FL: University of FL, 131 pp. (CFW-88-08) 1988.

[25] Treloar, G.J., Owen, C., Fay, R. 'Environmental assessment of rammed earth construction systems', Structural survey 2001a; 19(2), 99-105.

[26] Treloar, G.J., Love, P.E.D., Holt, G.D. Using national input-output data for embodied energy analysis of individual residential buildings, Construction Management and Economics 2001b;19, 49-61.

[27] Lenzen, M., Treloar, G. J. Embodied energy in buildings: wood versus concrete-reply to Borjesson and Gustavsson, Energy Policy 2002; 30, 249-244.

[28] Lenzen, M., Dey, C. Truncation error in embodied energy analysis of basic iron and steel products. Energy 2000; 25, 577-85.

[29] Lenzen, M., Munkgaard, J. Energy and CO2 life-cycle analysis of wind turbine. Renewable Energy 2002; 26, 339-362.

[30] Machado, G., Schaeffer, R., Worrell, E. Energy and Carbon embodied in the international trade of Brazil: an input-output approach. Ecological Economics 2001; 39, 409-424.

[31] Ma, T. Ecological element analysis in Chinese foreign trade. PhD Dissertation. Shanghai, University of Fudan, China, 2005 (in Chinese).

[32] Costanza, R. Embodied Energy Basis for Economic-Ecologic Systems. PhD Dissertation. Gainesville, FL: University of Florida (CFW-79-02), 1979.

[33] Costanza, R. Embodied energy and economic valuation. Science 1980; 210,1219-1224.

[34]Costanza, R. Economic values and embodied energy: reply to D.A. Huettner. Science 1982; 216, 1141-1143.

[35] Costanza, R., Herendeen, R.A. Embodied energy and economic value in the United States economy: 1963, 1967, and 1972. Resources and Energy 1984; 6, 129-164.

[36] Wu, R.H., Chen, C.Y. Energy intensity analysis for the period 1971-1984: a case study of Taiwan. Energy 1989; 14(10), 635-641.

[37] Limmeechokchai, B., Suksuntornsiri, P. Embedded energy and total greenhouse gas emissions in final consumptions within Thailand. Renewable and Sustainable Energy Reviews 2007; 11, 259-281.

[38] Zhou, J.B. Embodied Ecological Elements Accounting of National Economy. Ph. D. Dissertation, Peking University, China, 2008, (in Chinese).

[39] Buchanan, A.H., Honey, B.G. 1994. Energy and carbon dioxide implications of building construction, Energy and Buildings 20, 205-217.

[40] McGregor, P. G., Swales, J.K., Turner, K. The CO2 'trade balance' between Scotland and the rest of the UK: Performing a multiregion environmental input-output analysis with limited data. Ecological Economics 2008, 66(4), 662-673.

[41] Department of National Accounts, National Bureau of statistics Input-Output Tables of China. China statistics press, Beijing, 2006 (in Chinese).

[42] National Economic Accounting Department (Ed.), National Bureau of Statistics of China. Input-Output Tables of China (2002), Beijing: China Statistics Press, 2006.

[43] China Statistical Yearbook (CSY) China Statistics Press, Beijing, 2006 (in Chinese).

[44] General Administration of Quality Supervision, Inspection and Quarantine of China (GAQSIQ). Industrial classification for national economic activities, GB/T4754-2002. Standards Press of China, Beijing, 2002 (in Chinese).

[45] Jiang, M.M., Zhou, J.B., Chen, B. and Chen, G.Q. Emergy-based ecological account for the Chinese economy in 2004. Commun Nonlinear Sci Numer Simulat 2008; 13(10), 2337-2356.