A National Accounting Framework for the Petroleum Cycle: A Case Study of China

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1 Sep., 2016 Journal of Resources and Ecology Vol. 7 No.5 J. Resour. Ecol (5) DOI: /j.issn x A National Accounting Framework for the Petroleum Cycle: A Case Study of China LIU Xiaojie, LIU Litao *, CHENG Shengkui, SHEN Lei, LU Chunxia Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing , China Abstract: In a world of climate change and socio-economic development, oil is the strategic resource that is closely intertwined and interdependent. Tracing the evolution of petroleum resources flow is fundamental to understanding petroleum supply and demand, and can also serve as the basis for assessing CO 2 emissions from petroleum products. This paper aims to provide a petroleum products flow accounting framework that divides petroleum flow into four phases, three flows, three libraries, and two processes, and summarizes the approach to measure and analyze petroleum resources flows. It takes China as an example for empirical research, and finds that: 1 China s petroleum production, consumption and import have significantly increased over the past two decades, and the combination of increasing demand and limited supply have created an urgent need for China to diversify its petroleum sources globally to ensure its oil security. 2 Final consumption accounts for the use of most petroleum products and special attention should be paid to the losses in the petroleum refining process. 3 With the exception of crude oil, petroleum product flows among various sectors has changed greatly. Particularly, the flow of petroleum products into transport and residential consumption has trended upward significantly, whereas the flow to industry is trending downward. 4 CO 2 emission data shows that CO 2 emission amounts increased rapidly from 456Mt in 1993 to 1517Mt in Previously, the top three CO 2 emitters were the industrial sector, the transport sector including the transport, storage and post segments, and the thermal power sector. Currently, the largest emitters are the transport sector, the industrial sector and the residential consumption sector. Finally, poorly demarcated system boundaries and incomplete databases and models constrain research on industry flows of petroleum resources for non-energy use. Key words: flow framework; petroleum cycle; China 1 Introduction Petroleum is the world's key strategic resource, and is widely used in transportation, chemical, pharmaceutical, and numerous other industries. Petroleum is not only essential to the development of the social-economy, but also emits anthropogenic greenhouse gas (GHG) during its life cycle (Figure 1). Greenhouse gas emissions first occur during crude oil exploitation, petroleum refining and petrochemical production phases, afterwards during the consumption and petrochemical products phases, and finally they occur in the waste collection and disposal phases. The massive growth of petroleum demand over the past years, due largely to population growth, urbanization and industrialization, has not only led to concerns of petroleum depletion and supply disruption over the long term, but also results in adverse environmental effects. A fair amount of study has been dedicated to exploring options to ensure oil security; such studies are usually based on assessing constructed simple and aggregated indicators. Examples include oil vulnerability index (Forfás. 2006; Gupta. 2008), supply risk and offset (APERC. 2007), oil Received: Accepted: Foundation: National Natural Science Foundation of China ( ; ; ; ; ) *Corresponding author: LIU Litao. liult@igsnrr.ac.cn. Citation: LIU Xiao-jie, LIU Li-tao, CHENG Sheng-kui, et al. A National Accounting Framework for the Petroleum Cycle: A Case Study of China, Journal of Resources and Ecology, 7(5):

2 LIU Xiao-jie, et al.: A National Accounting Framework for the Petroleum Cycle: A Case Study of China 387 Fig.1 A simplified calculating schematic of the MFA model import diversification (Jansen et al. 2004; Vivoda. 2009; Cohen et al. 2011), oil dependence costs (Greene. 2010), oil supply risk (Zhang et al. 2013; Yang, et al. 2014) and others. Furthermore, increasingly unbalanced production and consumption reshape the petroleum industry and have a profound impact on global petroleum resources flow. A considerable amount of effort has been dedicated to the empirical study of the global oil trade network from the complex network theory perspective (Watts et al. 1998; Barabási et al. 1999; Ji et al. 2014; Zhong et al. 2016; Yang et al. 2015). Additionally, Zhao et al. (2010) established the world's petroleum flow trajectory frame for the early 21st century (Zhao et al. 2010). Zhao et al. (2006, 2008, and 2009) researched the formation mechanism and features of interprovincial and interregional petroleum resources flow in China during the late 20th century and early 21st century. Owing to a lack of physical characterization of the entire petroleum cycle, these models neglect mass-balanced linkages and feedback (Liu et al. 2013). Understanding the entire petroleum cycle and tracing the complexity of national petroleum flow is fundamental in order to identify inefficiencies and potential savings and to develop effective strategies for sustainable petroleum resource management. Material/substance/resources flow analysis has been widely used for more than three decades in resource conservation and recovery, production design, waste treatment, life cycle assessment, and others fields. It aims to address long-term issues of resource depletion, environmental impacts mitigation and waste management (Brunner. 2004; Cheng et al. 2005; Chen et al. 2008). For example, the material/substance flow analysis approach has been employed to characterize socio-metabolic transition of infrastructure (Müller et al. 2013), copper (Graedel et al. 2004), zinc (Graedel et al. 2005), iron (Wang et al. 2007), aluminium (Liu et al. 2013) and other substances. However, studies that address the entire cycle of petroleum in terms of efficiency and emissions are lacking. This lack, in part, reflects the lack of a descriptive framework for the petroleum cycle, and more importantly, its material flow. Although petroleum s share of total primary energy consumption decreased from 48% in 1973 to 33% in 2013, petroleum still accounts for the largest share today, followed by coal (30%) and gas (24%) (BP, 2015). Apart from the combustion of petroleum, some petroleum is used for nonenergy applications. Generally, energy use refers to petroleum consumed as a fuel or transformed into fuel (e.g., gasoline, kerosene, diesel and others). Non-energy use consists of two components: first, petroleum consumed by the chemical industry as feedstock (e.g., the use of naphtha for olefins production in steam crackers), and second, refinery products and other solid carbon consumed for non-energy purposes (e.g., the use of lubricants for transportation, the use of bitumen in building sector, etc.) (IEA, 2005a, b; Weiss et al., 2008). Although the share of petroleum used for energy decreased from 88.4% in 1973 to 83.8% in 2013, petroleum for energy still dominates global petroleum consumption (IEA, 2015). In addition, petroleum consumption is second only to that of coal as a contributor to greenhouse gas in the atmosphere, accounting for almost 33% of the global carbon emissions. At present, research on petroleum resources flow for energy use continues to become more detailed and thorough (Simon et al. 2011), while the studies on petroleum resources flow for non-energy use are relatively few. There remains considerable uncertainty regarding the complex substances, energy flow and corresponding CO 2 emissions involved in non-energy use (Patel et al. 2005). Considering petroleum s role as the most used energy resource worldwide and the second largest contributor of GHGs, we selected petroleum as our research subject. Moreover, China faces a dual challenge. It must satisfy the rapid growth in demand for petroleum, while at the same time dramatically curbing GHG emissions (IPCC 2007; IEA 2009; Liu et al. 2013; Zhang et al. 2011). China consumes more than 12% of the world s petroleum and is the biggest emitter of GHGs. GHGs from petroleum consumption constitute about 12% of China s carbon emissions. Moreover, almost 85% of the petroleum was used for energy production in 2013 (DES et al., 2014). In order to address climate change, the Chinese government voluntarily took action and announced that by 2020 China would reduce emissions of carbon relative to per capita GDP by 40% to 45% of the 2005 level. At the 2014 APEC meeting, the Chinese government promised that China s emissions would peak around 2030 and that the country would strive to fill one-fifth of its energy needs from non-fossil fuels and other energy sources. This paper focuses on petroleum resources industry flow and aims first to work out an analytical framework and calculation approaches for petroleum resources industry flow. It then takes China as an example to analyze the petroleum cycle for energy use and identify the potential environmental impact embedded in the cycle, thereby laying the foundation for petroleum resource conservation and mitigation of GHG emissions. 2 Petroleum resources industry flow system 2.1 System boundaries The analytical framework for petroleum resources industry flow is shown in Figure 2. Using relevant studies as reference

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4 LIU Xiao-jie, et al.: A National Accounting Framework for the Petroleum Cycle: A Case Study of China 389 points (Chen et al. 2008), this paper divides petroleum resources industry flow into four phases, three flows, three libraries, and two processes. (1) Four phases Crude oil exploitation (P1). This refers to the obtaining of crude oil from nature through exploration, drilling, mining and other processes. Crude oil exploitation is the first phase of petroleum flow. Crude oil supply relies partly on domestic exploration and partly on imports from abroad. Petroleum refining and petrochemical production phase (P2-P4). This is the process in which crude oil is used as the raw material to produce petroleum and petrochemical products. The production of petroleum and petrochemical products consists of three processes. The primary process is to refine crude oil via atmospheric distillation and vacuum distillation after pretreatment (desalting and dehydration), so as to get light distillate, heavy distillate and residual petroleum, respectively. On the basis of primary processing, catalytic cracking, hydrocracking, delayed coking, catalytic reforming, alkylation and petroleum refining are conducted for heavy distillate and residual petroleum, to obtain petroleum products (such as gasoline component, kerosene, diesel, lubricating oil, fuel oil and coke), and petrochemical process raw materials (including alkynes, olefins, aromatics and synthesis gas). This is known as secondary processing. The third processing continues to process the alkynes, olefins, aromatics and synthesis gas obtained in the secondary processing, in order to produce a variety of chemical products and gasoline components. Consumption and petrochemical products phase (P5). This is the phase where petroleum products (such as gasoline, kerosene, diesel petroleum, lubricating oil, fuel oil and coke, etc.) and petrochemical products (such as rubbers, resins, fibers, detergents, etc.) are consumed in the form of fuels or raw materials in such sectors and industries as animal husbandry, forestry, agriculture, fishery, water conservancy, manufacturing, construction, transportation, warehousing and post, telecommunications, wholesale, retail, food and beverage, etc. Waste collection and disposal phase (P6-P7). The different ways in which petroleum is used result in varying methods of collecting and treating the waste that is generated. Some of the gas generated by the use of petroleum to produce energy is directly discharged into the environment, while the other part can be trapped or abated through carbon capture and biological carbon sequestration. The waste generated from the non-energy use of petroleum is treated in the following ways: some wastes with a longer life cycle are recycled back into production and consumption sectors (such as rubbers, fibers, etc.) for secondary use; some are recycled and absorbed within cement industries, etc.; some petroleum-based raw materials are partially or fully oxidized in industrial processes (such as naphtha, ethane, solvents, lubricants, etc.); some go into landfills for degradation by natural processes; and some are carried into incineration plants for incineration. (2) Three flows The three flows are material flow, emission flow and trade flow. Material flow refers to the flow of raw materials, semi-finished and finished products along with the production, exchange, distribution and consumption of petroleum and petrochemical products within the boundaries of the system. The study of material flow aims to identify the process and balance of matter, energy and related carbon flows within the system. Emission flow refers to the waste emissions from the above-mentioned transfer of petroleum and petrochemical products within system boundaries; the study of emission flow aims to identify CO 2 emissions from exhaust gases and carbon flows from solid waste emissions. Trade flow refers to the material, energy and carbon flow resulting from the exchange of petroleum and petrochemical raw materials, semi-finished and finished products inside and outside the system; the study of trade flow aims to identify the impact of total trade flow and structural change on system energy and carbon flow. (3) Three stocks The three stocks include one natural library and two man-made stocks. Lithosphere and tailings constitute the natural stock (Müller et al. 2010). The two man-made stocks are the energy use library and the non-energy use stock. The energy use stock consists of national strategic reserve stocks and civil (private and corporate) reserves; it generally exists for a short time and is subject to policy, economic and other factors. As crude oil can be quickly processed into various petroleum products such as gasoline, kerosene and diesel that meet consumer demands, it is generally chosen for the national strategic reserve. However, civil reserves are mainly used to meet daily needs, and therefore these reserves are generally gasoline, kerosene, diesel and other fuel products. The non-energy use stock includes rubbers and fibers held within the society and economy, solid waste in landfills, garbage in municipal waste incineration plants and other forms of non-energy resources. These generally exist for a long time and depend on their life cycle in society. (4) Two processes The analytical framework for petroleum resource flow consists of a conversion process (P1-P7) and a market exchange process (M1-M6). The conversion process is used to characterize input and output balance, while the market exchange process is used to describe the supply and demand balance of materials and products on domestic and international markets under the coordination of trade flows and domestic logistics. 2.2 Components Petroleum resources industry flow is mainly composed of the three elements: material, energy, and value (figure 2). (1) Material. Material flow in petroleum resource indus-

5 390 Journal of Resources and Ecology Vol. 7 No. 5, 2016 tries mainly consists of the production material flow from processing crude oil into finished petroleum and chemical raw materials, the transport material flow inherent in the transportation of petrochemical products, the consumption material flow that is formed as end products that enter into production and daily life use, and the discharge material flow formed by the wastes that result from production and daily life use. (2) Energy. The entire petroleum resource industry flow is accompanied by energy transfers and conversion. Energy is transformed from one form into another at a specific ratio, and though some energy continues the transfer and acting, there is always some loss in the form of heat (entropy production). Energy always flows from high energy levels to low energy levels, and there is a certain loss (namely, conversion efficiency) when energy moves from one level another level. The energy flow of the petroleum resources industry flow is based on material flow. (3) Value. Value flow runs throughout the entire process of the petroleum resources industry flow, and includes value- added and non-value added activities such as petroleum resources production planning, processing, conversion, transportation and so on. The value flow of petroleum resources is attached to the material flow, and undergoes periodic changes along with petroleum resource exploitation, processing, conversion, consumption, waste, recycling and other processes. As a result, value flow exhibits hidden, continuous and cyclical characteristics. In addition, the value of petroleum resources follows the universal law of flowing from low value-added sectors to high value-added ones, hence identifying the optimal allocation of petroleum resources. 3 Calculation principles and approaches Petroleum resources flow analysis is based on the law of conservation of matter, which indicates that matter will never appear or disappear without reason, but instead converts from one form to another form. Based on the law of conservation of matter and the simplified calculating schematic of the MFA model (Figure 1) proposed by Dahlström et.al (2004), Müller et.al (2006), Chen et al (2008) and Liu et.al (2011), this paper constructs the analytical framework and calculation approach for petroleum resources flow and embedded CO 2 emissions. The MFA model defined in Figure 2 includes the conversion process (blue) and the market exchange process (green). Of the two, the conversion process complies with the law of conservation of matter and is connected by black arrows. The market exchange process, while following the law of conservation of matter, is also subject to the laws of market supply and demand, and is connected by blue arrows. Of the three stocks, the natural library (orange) includes the lithosphere, tailings, etc.; the two man-made libraries are the energy use library (yellow) and the non-energy use library (pin1k). In this analysis, the total flow of petroleum resources follows the law of conservation of matter, while the total flow of carbon of petroleum resources and carbon emissions are based on the balance of carbon equivalent. (1) Calculation of material flow balance F1 F2 F3 (1) F4 F2 1 E S (2) F5 F4 S (3) (2) Calculation of conversion efficiency TC F 2 / F1 (4) (3) Calculation of carbon equivalent X m x (5) ij i ij Wherein, i=1, k is the type of products; j=1 n, the types of elements. In terms of types of products, the focus is on gasoline, kerosene, diesel and fuel oil refined from crude oil; in terms of types of elements, the focus is on tracking the carbon element of the petroleum resources flow, where j=1. X ij is the carbon equivalent, m i the total amount of product flow, x ij the carbon element content of the corresponding product flow. The equation can also be expressed by the matrix: X m j X m x x x k k k1 kj (4) Calculation of carbon dioxide emissions This paper calculates CO 2 emissions for each industry involved in the petroleum resources flow based on the carbon emissions approach published by IPCC (2006). Wherein: A i is the apparent consumption of energy i; B i is the potential emission factor of energy i; C i is the carbon oxidation rate of energy i; and D i is the average low calorific value of energy i. The calculation formula is as follows: k x (6) CO2emissions Ai B i Ci Di 44 /12 (7) (5) Calculation of stock i t t stock () input (t) t output () t stack ( 0) t (8) 0 t0 m t m d m t d m t Wherein m stock (t 0 ) is the stock of the period t 0 (base period), and m stock (t) is the stock of the period t (reporting period). The stock of the reporting period equals the sum of the inflow and outflow stock changes from period t 0 to t and the stock of period t 0. 4 Empirical analysis of petroleum flow in China We selected petroleum products mentioned in the energy balance of China to construct a petroleum flow framework,

6 LIU Xiao-jie, et al.: A National Accounting Framework for the Petroleum Cycle: A Case Study of China 391 and then we compared the petroleum flow of 1993 with that of 2013 to discover the features and characteristics of petroleum flow and how it has evolved. The analytical framework and calculation approaches constructed in this paper are applied to calculate and analyze the total amount of petroleum products flow in each phase, while flow efficiency and carbon emissions are also investigated. Data for the production, import, export and consumption of petroleum products is mainly from government and industry statistical publications, including China s Industrial and Transportation Energy Statistics , China Energy Statistical Yearbook and China Statistical Yearbook Some parameters for the estimation of CO 2 emissions (Table 1) are from the 2006 IPCC Guidelines for National Greenhouse Gas Inventories (IPCC 2006). On this basis, R was introduced to facilitate the network analysis, and we turn to rcharts in R to provide a dynamic snapshot of petroleum resources flow in China. Material and trade flows illustrate that China s petroleum production, consumption and imports have significantly increased over the past two decades. China urgently needs to ensure its oil security. Production rose from 149Mt in 1993 to 500Mt in 2013, while consumption increased from 147Mt in 1993 to 500Mt in The differences between production and consumption are the result of changes in stocks and statistical discrepancies. Annual growth rates for both production and consumption are greater than 7 percent. Moreover, China s petroleum imports increased significantly from less than 1Mt in 1993 to 343Mt in 2013, while exports increased only slightly from 18Mt in 1993 to 42Mt in China becomes a net petroleum importer in 1993, and three years later became a net crude oil importer. Petroleum net imports expanded from 11Mt in 1993 to 301Mt in At the same time, oil import dependence increased from 7.5% in 1993 to more than 60% in Increasing demand and limited supply has created an urgent need for China to diversify its petroleum sources around the world. Although China s crude oil and fuel oil import dependence has increased sharply, China also became a net gasoline exporter in 1994 and net kerosene and diesel exporter in Crude oil import dependence rose dramatically from 3% in 1993 to 58% in 2013, while fuel oil import dependence increased considerably from 15% in 1993 to 31% in On the other hand, LPG import dependence declined slightly from 13% in 1993 to 12% in Gasoline, kerosene, and diesel oil import dependence decreased gradually from 1%, 15% and 20% in 1993 to 5%, 15% and 2%, respectively, in In addition, China is also a net naphtha, lubricants, white spirit, bitumen asphalt, and petroleum coke importer. The import dependence of these items in 2013 was, respectively, 9%, 14%, 1%, 15%, 32% and 12%. Simultaneously, China is a net exporter of paraffin waxes, with export volume of about 0.5Mt. Material flow analysis also indicates that final consumption uses the most petroleum, and that we should pay special attention to the losses in petroleum refining procedure. As of 1993, more than 81% of petroleum flow went to final consumption, and of this total percentage, 51% was consumed by industry. About 15% of petroleum consumed was in the transformation phase, including consumption for power generation, heating and gas production. Other petroleum was lost during petroleum refining and other processing procedures. Losses in the petroleum refining phase accounted for 2% in The petroleum flow situation has greatly changed since 1993, and the share of petroleum flow into final consumption had risen rapidly to 95% by However, the share of petroleum consumed by industry in Table 1 Some parameters for the estimation of CO 2 emission Fuel Type Description Default Carbon Content (kg/gj) Default Carbon Oxidation Factor Default CO 2 Emission Factor (kg/tj) Default Net Calorific Value (NCV, TJ/Gg) A B C=A*B*44/12*1000 D Crude Oil Gasoline Kerosene Diesel Oil Fuel Oil Naphtha Lubricants Paraffin Waxes White spirit Bitumen Asphalt Petroleum Coke LPG Refinery Gas Other Petroleum Products

7 392 Journal of Resources and Ecology Vol. 7 No. 5, 2016 final consumption dropped dramatically to about 32%. Similarly, the proportion of petroleum flow into transformation fell to less than 2%. And the rate of loss during transformation declined slightly from 5% in 1993 to 4% in Additionally, China s steady growth in petroleum products demand led to increasingly greater crude oil flow into petroleum refineries. Crude oil consumed by petroleum refineries rose from 131Mt in 1993 to 478Mt in Losses during petroleum refining significantly increased from 3Mt accounting for 2% of total petroleum flow in 1993 to 16Mt accounting for 4% in Given the large amounts lost, improving the efficiency of refining processes to reduce crude oil losses should be a priority. With the exception of crude oil, petroleum products flow among various sectors has changed greatly. In particular, petroleum products flow into the transport and residential consumption sectors is trending significantly upward, whereas the flow into the industrial sector is trending downward. Crude oil flow remained relatively stable; the share of crude oil that flowed into transformation increased slightly from 92% in 1993 to 98% in Additionally, the share of kerosene, diesel oil, LPG and other petroleum products in transformation output increased steadily from 3%, 28%, 3%, 14% in 1993 to 5%, 33%, 5% and 15%, respectively, in But the share of gasoline and fuel oil decreased dramatically from 25% and 25% in 1993 to 19% and 5% in Naphtha, bitumen asphalt, petroleum coke, and refinery gas accounted for 8%, 3%, 3% and 3% in Additionally, there has been a significant upward trend of petroleum products consumed by transport and residential consumption. For example, the share of gasoline that flowed into transport and residential consumption increased from 41% and 0% in 1993 to 47% and 20% in The share of diesel oil increased from 19% and 0% in 1993 to 64% and 6% in The share of LPG increased from 0% and 36% in 1993 to 3% and 65% in And the share of fuel oil and kerosene that flowed into transport increased dramatically from 4% and 9% in 1993 to 36% and 92% in However, the flow of petroleum into industry has trended downward. The share of gasoline, kerosene, diesel oil, fuel oil and LPG that flowed to industry declined sharply from 27%, 4%, 28%, 96% and 61% in 1993 to 6%, 1%, 10%, 61% and 25% in Finally, CO 2 emission estimates show that the amount of CO 2 emissions have grown rapidly from 456Mt in 1993 to 1517Mt in During this same period, the three largest emitters of CO 2 have gone from the industrial sector, the transport sector including the transport, storage and post segments, and the thermal power sector to the transport sector, the industrial sector and the residential consumption sector. As of 1993, the industrial sector was the largest emitter, with 186Mt of CO 2 emissions constituting 41% of total CO 2 emissions. Among these emissions 66% were from energy use and 34% were from non-energy use. The transport sector was the second largest emitter, with 71Mt of CO 2 accounting for 16% of total CO 2 emissions. The thermal power sector was the third largest emitter, accounting for 11% of total emissions. The agriculture sector including farming, forestry, animal husband, fishery and conservancy, the heating supply sector, the residential consumption sector, the service sector, and the construction sector accounted for 7%, 4%, 3%, 2% and 2%, respectively. Additionally, CO 2 emissions from other sector accounted for 13% and loss accounted for 2%. Since 1993, the amounts of CO 2 emissions by sector have changed dramatically. The three largest CO 2 emitters in 2013 were the transport sector, industrial sector and the residential consumption sector, accounting together for about 80% of total CO 2 emissions. The transport sector is the largest emitter accounting 39%, while the industrial sector accounts for 31%, and residential consumption sector for 10%. The remaining sectors such as the construction sector, agriculture sector, the service sector, the heating supply sector, the thermal power sector and others account for 7%, 3%, 1%, 1%, 1% and 7%, respectively. Hence, policies designed to mitigate CO 2 emissions in China should focus on the transport, industrial and residential consumption sectors. 5 Conclusions and discussion 5.1 Conclusions This paper constructs a framework to analyze petroleum resources flow. The framework divides petroleum flow into four phases, three flows, three stocks, and two processes. Additionally, the paper presents an approach to measure and analyze the flow of petroleum resources and carbon emissions. Finally, we carry out empirical research to ascertain the situation in China and find that: (i) China s petroleum production, consumption and imports have significantly increased over the past two decades, and increasing demand and limited supply have created an urgent need for China to diversify its petroleum sources around the world to ensure oil security. (ii) Most petroleum products were consumed by final consumption and special attention should be paid to the losses in petroleum refining processes. (iii) With the exception of crude oil, petroleum products flow among various sectors has changed greatly. In particular, petroleum products flow into the transport and residential consumption sectors has trended upward significantly, whereas petroleum products flow to the industrial sector is trending downward. (iv) CO 2 emission estimates show that the amount of CO 2 emissions grew rapidly from 456Mt in 1993 to 1517Mt in During the period 1993 to 2013, the sectors emitting the most CO 2 have gone from the industrial sector, the transport sector including the transport, storage and post segments, and the thermal power sector to the transport sector, the industrial sector and the residential consumption sector.

8 LIU Xiao-jie, et al.: A National Accounting Framework for the Petroleum Cycle: A Case Study of China 393 Fig.3 Petroleum resources flow in China from 1993 to Discussions The empirical analysis of petroleum resources flow in this paper analyzes only direct emissions of petroleum resources flow without taking into account indirect emissions from power consumption. More importantly, based on IPCC (2006) Approach I, this paper estimates CO 2 emissions from both energy use and non-energy use, but these flow-based approaches ignore the impact on CO 2 emissions of life-time, recycling and disposal of petroleum products. NEU CO 2 emissions (non-energy use carbon dioxide) from fossil fuels are an important source of future GHG emissions and should not be overlooked (Masanet et al. 2009). IEA s study of OECD countries shows that in 2000, 13.2% of petroleum products in OECD countries were used in non-energy forms (IEA 2002), and this proportion has increased gradually with the passage of time. As for China, more than 15% of petroleum products were used in non-energy forms. For this reason, in addition to research on

9 394 Journal of Resources and Ecology Vol. 7 No. 5, 2016 the energy uses of petroleum resources, more efforts should be made to analyze the non-energy use of petroleum resources and the corresponding carbon emissions. At present, the factors restricting the research on industry flow of petroleum resources for non-energy use are as follows: (1) System boundary demarcation. Consistently reliable energy statistics are an important basis for GHG accounting and for developing effective energy conservation policies. Currently, the biggest uncertainty in national and international energy statistics comes from system boundary demarcations for non-energy use of fossil fuels and statistics (Patel et al, 2005), including such issues as the flow of products into chemical industries in the form of raw materials, and refining and coke oven products consumed in non-energy forms (such as asphalt, lubricants, etc.). Due to relatively complex issues and energy flow processes in the refining and chemical industries, inconsistent and even incorrect system boundary demarcations result in significant uncertainty in non-energy use data. Currently, there is no international consensus on system boundary demarcations for non-energy uses of fossil fuels. Figure 4 is a boundary demarcation schematic of energy use and nonenergy use of fossil fuels based on recent research. Vaguely defined system boundaries make official data on non-energy use compiled by different countries inconsistent or incomparable. (2) Non-energy using model In GHG inventory guidelines, IPCC proposes two reference approaches (IPCC-RA) and a sector approach (IPCC- SA) to calculate GHG emissions. IPCC-RA is used only to calculate fuel CO 2 emissions and to crosscheck IPCC-SA calculated results of countries with limited data. The IPCC- RA model is mainly to work out national CO 2 emissions by deducting the carbon stored in products from apparent national total of carbon consumption. The fossil carbon stock is calculated as follows (Houghton et al. 1997): Carbon stock (t carbon) = Non-energy use (J) CO 2 emission factor (t carbon/j) carbon storage factor (%) (9) A top-down model, IPCC-RA is based entirely on energy statistics. IPCC-SA, however, is a bottom-up model, in which CO 2 emissions from the use of fossil fuels are divided into four different source categories, including fuel combustion emissions, industrial process emissions, solvents and other product use emissions and waste emissions. In, the calculation of CO 2 emissions from various source categories should use a bottom-up method based on energy statistics, but for the calculation of carbon stocks, IPCC-SA uses equation 9 in the same way as IPCC-RA (Neelis et al. 2005a). The limitations of these two approaches are as follows: Firstly, IPCC-RA does not have clear workframe of whether to calculate energy use CO 2 emissions, or CO 2 emissions from all fossil fuels (energy and non-energy use). Secondly, the absence of a reasonable definition of important nonenergy use processes in energy statistics is a common defect for both the IPCC-RA and IPCC-SA models. For example, the absence of a reasonable definition of what constitutes a steam cracking process results in overestimation or underestimation of CO 2 emissions by both models. Thirdly, both the IPCC-RA and IPCC-SA models use default constants as carbon storage factors, but it is not clear to what extent annual changes in carbon stock factors affect non-energy use CO 2 emissions and carbon stocks and, therefore, it is not known whether the carbon storage factors set for one or several years is reasonable or not. In light of this, for a more accurate accounting of nonenergy use CO 2 emissions and carbon stocks of fossil fuels, researchers developed the non-energy use emissions accounting tables (NEAT), which is built on carbon flow analysis (Neelis et al. 2005b). The biggest difference between NEAT and the IPCC-RA and IPCC-SA models in calculating non-energy use CO 2 emissions and carbon stocks is that NEAT is based on MFA which generally estimates non-energy use CO 2 emissions without energy statistics (MFA itself is an improved approach, and the carbon storage factor obtained via MFA tends to be more accurate than the default value of IPCC), while the IPCC-RA and IPCC-SA models are based on energy statistics and default storage factors. The biggest problem of IPCC-RA and IPCC-SA models lies in the absence of an appropriate and consistent definition of non-energy use. The NEAT model offers an appropriate and consistent definition of non-energy use. It serves as the only tool at present for a systematic analysis of non-energy use carbon flow of all fossil fuels, and it provides support for collecting energy statistics and for developing national GHG inventories. At the same time, the biggest drawback of the NEAT model is that it requires a great deal of data. It needs the data for 77 organic chemicals, 18 inorganic chemicals, metals and raw data types, and specific energy consumption data for some industrial processes. In summary, future petroleum flow analysis should undertake research in the following areas: First, clear system boundary demarcations need to be defined. These should cover system boundaries for the energy and non-energy use of petroleum resources flow, and clarify the exchange and conversion of matter and energy in each phase of the life cycle of petroleum resources flow. Second, a petroleum resources flow database should be established, and for petroleum non-energy use, databases for organic chemicals, inorganic chemicals, metal and material types should be developed. Databases are also needed with data on energy consumption of primary industrial processes, lifecycles for major organic chemicals and inorganic chemicals (including production, consumption, recycling and disposal, etc.), carbon storage factors, etc. Third, a model to calculate China s petroleum energy use and non-energy use carbon emissions should be built. References APERC A quest for energy security in the 21st century. Institute of

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11 396 Journal of Resources and Ecology Vol. 7 No. 5, 2016 Zhao Y, Hao L S The forming mechanism of crude petroleum flow in China. Geographical Research, 27(5): (in Chinese) Zhao Y, Hao L S Analysis on the region classification of crude petroleum flow in China. Journal of Natural Resouces, 24(1): (in Chinese) Zhong WQ, An HZ, Fang W, Gao XY, Dong D Features and evolution of international fossil fuel trade network based on value of emergy. Applied Energy, 165: 刘晓洁, 刘立涛, 成升魁, 沈 镭, 鲁春霞 中国科学院地理科学与资源研究所, 北京 摘要 : 石油作为现代工业社会的血液和全球性重要的战略资源, 被广泛用于交通运输 化工 医药 制造等各行各业 加强石油资源流动研究, 有助于理解石油在产业内部以及其他产业之间的流动过程 石油资源流动分析框架及测算方法研究是开展石油供需研究的基础与前提, 同时也是石油产品二氧化碳排放评估研究的基础 鉴于此, 本文构建了石油资源流动分析框架, 把石油资源产业流动过程划分为 4 阶段,3 种流,3 种库和 2 个过程, 归纳总结了石油资源流动测算分析方法 以中国为例开展实证研究, 研究结果显示 :1 过去二十年中国石油生产 消费和出口量迅猛增长, 快速正价的需求和有限的供应能力导致中国石油进口来源呈现多元化, 从而实现国家层面上的石油安全 ;2 终端消费掉多数石油产品, 应该特别关注石油炼制过程中的损失情况 ;3 除去原油, 不同部门之间的石油产品流入量已经发展了巨大变化, 在交通运输和生活消费部门呈现明显的上升趋势, 而工业消费量呈现下降趋势 4 石油资源流动的 CO 2 排放而言, 从 1993 年的 4.56 亿 t 上升到 2013 年的 亿 t; 与此同时, 二氧化碳排放的前三名从工业 运输业 ( 包括运输业 仓储和邮政业 ) 火力发电业转变为交通运输 工业和生活消费 此外, 石油资源产业流动需进一步加强系统边界 数据库和针对非能源消费的石油资源流动模型研究等 关键词 : 流动框架 ; 石油资源流动 ; 中国