Identifying the environmental support and constraints to the Chinese economic growth—An application of the Emergy Accounting method

The economy of China keeps increasing at high rate, although a bit slower recently than in the past due to the international economic turmoil. The Chinese economic performance affects the world economy in many ways (from increased primary resource and commodity imports to a more active financial role of China worldwide). Not unexpectedly, several and diverse environmental problems are coupled with economic growth, linked to resource availability, competition for energy resources and the overall carrying capacity of the environment as a source and a sink. Monodimensional assessments of either economic growth or environmental aspects are unlikely to provide the needed understanding of development opportunities and potential environmental loading. We suggest in this paper an assessment of the evolution of Chinese Economy based on the Emergy Accounting method, developed by H.T. Odum in the Eighties and further refined more recently. The emergy approach is being increasingly applied worldwide, and in China as well, to study individual production processes, sectors and whole economies and provides a comprehensive picture of the interaction of economic growth and the environment, much useful for economic and environmental policy making. A set of emergy-based performance indicators was calculated with reference to the year 2009 and compared with previous studies from literature, by means of a standardization procedure to ensure consistency. The 2009 national Emergy/GDP ratio, an indicator of the emergy investment per unit of economic product generated, has been calculated respectively as 8.61E+11 solar equivalent joules/Yuan RMB (equivalent to 5.88E+12 sej/US$), showing a decreasing trend from 1975 up-to-date, similar to other countries over their development path. The Emergy Sustainability Index (ESI), an aggregate measure of economic performance and environmental load, also shows a decreasing trend signaling that the Chinese economic development is strictly coupled to non-negligible environmental stress and lower sustainability.     

Heat transfer—A review of 2003 literature

The present paper is intended to encompass the English language heat transfer papers published in 2003, including some translations of foreign language papers. This survey, although extensive cannot include every paper; some selection is necessary. Many papers reviewed herein relate to the science of heat transfer, including numerical, analytical and experimental works. Others relate to applications where heat transfer plays a major role not only in man-made devices, but in natural systems as well. The papers are grouped into categories and then into sub-fields within these categories. We restrict ourselves to papers published in reviewed archival journals.Besides reviewing the journal articles in the body of this paper, we also mention important conferences and meetings on heat transfer and related fields, major awards presented in 2003, and books on heat transfer published during the year.     

On the Second-Law inconsistency of Emergy Analysis

The paper argues against the claim made by Emergy Analysts that emergy is an exergy-based procedure. Both Emergy- and Exergy Analysis employ space- and time integrated energy input/output models to quantitatively assess the resource consumption of physical systems: the issue at stake is whether Emergy is embodied energy or embodied exergy. Although the compatibility of Exergy- and Emergy accounting procedures, the significance of the peculiar Emergy Algebra, and some cost-allocation issues have been studied in detail, a final agreement could not be reached, so that some doubt exists about the degree of compatibility of the two methods. The present paper shows that the definitions and the procedures employed in Emergy Analysis are in fact First Law-based, and that they neglect or misrepresent Second Law issues. This conclusion is reached by carefully reviewing and critically analyzing a series of general and specific procedures contained in the original Odum books and in some of the most representative publications by Emergy analysts.     

Emergy analysis of cassava-based fuel ethanol in China

Emergy analysis considers both energy quality and energy used in the past, and compensates for the inability of money to value non-market inputs in an objective manner. Its common unit allows all resources to be compared on a fair basis. As feedstock for fuel ethanol, cassava has some advantages over other feedstocks. The production system of cassava-based fuel ethanol (CFE) was evaluated by emergy analysis. The emergy indices for the system of cassava-based fuel ethanol (CFE) are as follows: transformity is 1.10 E + 5 sej/J, EYR is 1.07, ELR is 2.55, RER is 0.28, and ESI is 0.42. Compared with the emergy indices of wheat ethanol and corn ethanol, CFE is the most sustainable. CFE is a good alternative to substitute for oil in China. Non-renewable purchased emergy accounts for 71.15% of the whole input emergy. The dependence on non-renewable energy increases environmental degradation, making the system less sustainable relative to systems more dependent on renewable energies. For sustainable development, it is vital to reduce the consumption of non-renewable energy in the production of CFE.     

Emergy account for biomass resource exploitation by agriculture in China

On the basis of Odum's ecological economic measure of emergy as embodied solar energy, a system account of biomass resource exploitation by agriculture in China 2004 is developed in this paper, which supplements a former study on corresponding long-term historical trends during 1978 to 2000 (Chen et al., 2006. Emergy-based analysis of the Chinese agriculture. Agriculture, Ecosystems and Environment 115, 161–173). The aggregate fluxes and indicators for biomass resource exploitation in China 2004 are calculated and illustrated when compared with those for 2000 to elucidate the latest status of the Chinese agriculture as the exploitation sector for biomass resource. Data sources and algorithm are presented in detail as basic references for related analysis involving the ecological economy of biomass exploitation in agriculture.     

Emergy analysis of cropping–grazing system in Inner Mongolia Autonomous Region,China

An ecological energetic evaluation is presented in this paper as a complement to economic account for the cropping–grazing system in the Inner Mongolia Autonomous Region in China in the year 2000. Based on Odum's well-known concept of emergy in terms of embodied solar energy as a unified measure for environmental resources, human or animal labors and industrial products, a systems diagram is developed for the crop and livestock productions with arms and sub-arms for free renewable natural resource input, purchased economic investment, yields of and interactive fluxes between the cropping and grazing sub-industries. In addition to conventional systems indices of the emergy yield ratio (EYR), emergy investment ratio (EIR), environmental load ratio (ELR) and environmental sustainability index (ESI) introduced for congregated systems ecological assessment with essential implication for sustainability, new indicators of soil emergy cost (SEC), self-support intensity (SSI) and self-support orientation (SSO) are defined to characterize the desertification and internal recycling associated with the special agricultural system. Extensive emergy accounting is made for the cropping-grazing system as a whole as well as for the cropping and grazing subsystems. The overall cropping–grazing system is shown with outstanding production competence compared with agricultural systems in some other provinces and the national average in China, though confronted with severe desertification associated with soil loss. The production of crops has higher emergy density and yield rate per unit area as well as higher rate of soil loss than grazing system. The soil emergy cost defined as the soil loss emergy divided by the yield emergy is estimated to be of the same value for both of the subsystems, but the grazing activity is with less extraction intensity, leaving rangeland to rest and rehabilitate. Suggestions with regard to the local sustainability and national ecological security in northern China are explored for land-use policy making.     

生物质电厂节能降耗改造能值分析

以某生物质电厂为研究对象,应用能值理论,借助能值转换率η_(Tr)、能值产出率η_(EYR)、环境负载率η_(ELR)、能值可持续指数η_(ESI)等指标,对企业主要耗能设备降耗改造进行能值分析。研究结果表明:烟气余热回收技术改造后的能值转换率最低,但是环境负载率也最高,所有的改造技术都能提高能值产出率,除了烟气余热回收技术,其余节能技术在能源可持续指标上都有良好的表现。综合考虑经济效益和污染等问题,烟气余热回收虽然有很好的节能效果,但是会对环境造成一定的污染,而光伏水泵发电和变频改造技术则具有较为平衡的效果。     

Recent Developments in Heat Transfer and Energy Conservation: A Review of the Selected Papers from ISHTEC2012

It is our pleasure to present this special issue of Heat Transfer Engineering with a selection of papers presented at the 4th International Symposium on Heat Transfer and Energy Conservation, ISHTEC2012, held January 6–9, 2012, in Guangzhou, China. The conference was sponsored by the Key Laboratory of Enhanced Heat Transfer and Energy Conservation of Education of Ministry of China. More than 160 delegates including 42 foreign delegates from 16 countries came to the conference and there were more than 140 papers presented at the conference. The topics covered a wide variety of fields from new heat transfer theories, to micro heat transfer, to enhanced heat transfer technologies and the heat transfer problems in energy use systems. This special issue is a selection of the best 21 papers presented at the conference, including 2 review papers and 19 full-length research papers. The analysis of these papers showed that there are new trends in recent years in heat transfer and energy conservation: (1) New heat transfer theories are actively proposed to optimize heat transfer problems. (2) New alternative energy use technologies are being extensively investigated to meet the desire for a low carbon society. (3) Even for the seemingly traditional processes and equipment, new phenomena and findings are continuously disclosed, during which computational fluid dynamics has been more and more relied on.     

Emergy synthesis and simulation for Macao

Macao is a tourist city with a dense population and has a shortage of natural resources. Almost all of the city's life-support systems thus depend on imports of external resources. During the past 20 years, Macao has experienced an economic boom accompanied by rapid social development, in which the gambling industry and related tourism services have become the main economic activity. This paper employs emergy flow analysis to investigate and characterize the evolution and development of Macao from 1983 to 2003. In addition, Macao has experienced six periods of land reclamation since 1866, supported by large-scale importation of sand and rocks from China. By simulating the emergy trends using the STELLA dynamic modeling software, we predicted the evolution of Macao's development and trends in the coming 20 years. In 2025, the city's economy is estimated to be 15 times its current size as a result of Macao's territorial expansion. The exported emergy will increase slowly and then stabilize, the population will reach 593 185, and the area covered by Macao will expand to 38.91 km².     

Integrated energy,environmental and financial analysis of ethanol production from cellulosic switchgrass

Ethanol production from cellulosic sources such as switchgrass (Panicum virgatum L.) requires the use of natural resources, fossil fuels, electricity, and human-derived goods and services. We used emergy accounting to integrate the ultimate amount of environmental, fossil fuel, and human-derived energy required to produce ethanol from switchgrass. Emergy is the total amount of energy of one form required directly and indirectly to make another form of energy. Forty-four percent of required emergy came from the environment either directly or embodied in purchased goods, 30% came from fossil fuels either directly or embodied in purchased goods, and 25% came from human-derived services indirectly. Ethanol production per petroleum use (emergy/emergy) was 4.0-to-1 under our Baseline Scenario, but dropped to 0.5-to-1 under a scenario that assumed higher input prices, lower conversion efficiencies and less waste recycling. At least 75% of total emergy was from non-renewable sources. Energy ‘hidden’ in indirect paths such as goods and services was 65% of the total. Cellulosic-ethanol is not a primary fuel source that substitutes for petroleum because its production relies heavily on non-renewable energy and purchased inputs. It is a means for converting natural resources to liquid fuel.     

A key review on emergy analysis and assessment of biomass resources for a sustainable future

The present study comprehensively reviews emergy analysis and performance evaluation of biomass energy. Biomass resources utilization technologies include (a) bioethanol production, (b) biomass for bio-oil, (c) biodiesel production, (d) straw as fuel in district heating plants, (e) electricity from Municipal Solid Waste (MSW) incineration power plant, (f) electricity from waste landfill gas. Systems diagrams of biomass, which are to conduct a critical inventory of processes, storage, and flows that are important to the system under consideration and are therefore necessary to evaluate, for biomasses are given. Emergy indicators, such as percent renewable (PR), emergy yield ratio (EYR), environmental load ratio (ELR) and environmental sustainability index (ESI) are shown to evaluate the environmental load and local sustainability of the biomass energy. The emergy indicators show that bio-fuels from crop are not sustainable and waste management for fuels provides an emergy recovery even lower than mining fossil fuel.     

Evaluation of a building using the emergy method

Emergy (spelled with an m) is the energy of one kind, usually solar energy, which is required to make a service or product. The yearly emergy consumption/production of a building is evaluated considering the Solar Energy Laboratory (LESO) building on the campus of the Swiss Federal Institute of Technology of Lausanne (Switzerland). This experimental building was constructed according to special environmental considerations, such as important the use of passive gains (heat emitted from solar radiations, electric appliances and building users). It is therefore characterized by a very low energy consumption, equal to 232 MJ/m² year. The LESO building is occupied by faculty and students. Undergraduate and graduate students as well as faculty represent information inputs to the system with their emergy accounting for 94.6% of the emergy inputs to the building, equal to 3.3E18 sej/year (solar emjoules per year).“Educated students” (students who have completed a semester project, master’s or PhD research in the laboratory), publications, courses and services are the main outputs of the system. The four outputs are considered as co-outputs, as such the total emergy associated to the operation of the building as a structure is entirely assigned to each of them. The evaluation established that a student leaving the LESO building has a transformity (emergy per unit energy) equal to 2.4E8 sej/J, which is about three times higher than the one which he/she had upon arrival, representing the knowledge gained through conferences and interactions with other students and professors.Considering only energy and materials inputs, electricity was established to be the largest input to the system (2.7E16 sej/year). The total emergy of the material inflows was determined to equal 1.7E16 sej/year, paper being the largest material input (5.7E15 sej/year). The specific emergy (per mass) of some common building materials was also evaluated and compared to NRE (non-renewable energy).Finally, the question of uncertainties related to the determination and use of average transformities and emergy per mass values is addressed, and advantages and drawbacks of the emergy method are discussed in relation to other common evaluation methodology (exergy, embodied energy, life-cycle analysis).     

Sustainability improvement in combined electricity and freshwater generation systems via biomass: A comparative emergy analysis and multi-objective optimization

For energy systems, sustainability is a major concern that must be carefully considered when designed and established. Emergy analysis is an effective technique to scrutinize the sustainability of these systems. On the other hand, water shortage is seen to become a big problem in the close future; however, this problem can be effectively alleviated by combined electricity/water production plants, where waste heat is recovered to generate freshwater. This study applies emergy analysis to evaluate and improve the sustainability, renewability, environmental impacts, and economic aspect of such a plant, in which a multi-stage desalination (MSF) system is employed to recover the waste heat from a gas turbine (GT). The plant is fueled by biomass/natural gas (system I), natural gas (system II), and biomass (system III), and the above-mentioned features are compared for the different fuel types. To estimate chemical equilibrium state inside the gasifier, Lagrange's method of undetermined multipliers is applied. Also, considering exergy efficiency and emergy sustainability index as objective functions, biomass/natural gas-fueled system is optimized by adopting a multi-objective optimization approach based on the non-dominated sorting genetic algorithm II (NSGA II). To predict the optimized points' behavior, the Pareto optimal frontier of the system is utilized. The results reveal that using biomass as inlet fuel remarkably improves the sustainability index and reduces environmental impacts. The optimization results show that as sustainability index increases, exergy efficiency decreases. Also, the two optimized points of the system are found to have exergy efficiencies of 20.14% and 25.09% and sustainability indices of 24.67% and 13.60%.     

国际氢安全领域研究热点及最新进展——记第五届国际氢安全会议(ICHS 2013)

国际氢安全会议是氢安全领域的国际顶级会议,受到各国学术界、工程界和政府部门的高度重视。第五届国际氢安全会议(ICHS 2013)在比利时布鲁塞尔召开,会议的主题是"氢能技术与基础设施安全的新进展:向零碳能源进发"。大会共设9大类议题——氢气泄漏与扩散、氢气燃烧与爆炸、储氢安全、风险评估、氢与材料相容性、燃料电池安全、氢传感器、规范标准、氢安全教育,共收录论文99篇,组织报告会29场,重点关注的研究领域集中在氢气行为(泄漏、扩散、燃烧、爆炸)、储氢安全、风险评估三个方面。英、法、美、德四国是ICHS 2013文章收录数量的第一梯队,也是氢安全领域研究的主力军和ICHS的重要参与者。加拿大、日本、中国、荷兰排在文章收录数量的第二梯队。美、日、欧盟等氢能领域先进国家或地区都在积极研发推广氢能技术。我国在ICHS 2013的论文发表数量和领域覆盖面上都与先进国家存在一定差距,今后应积极投稿并参加会议,提升我国在氢安全领域的国际影响力和话语权。     

Resource consumption in Japanese agriculture and its link to food security

Energy security and food security are two key policy objectives of the Japanese government. However, their study and the policies that have targeted them have been disjointed at best. This paper explores the links between these two policy objectives by quantifying the resources used in (a) the agricultural sector as a whole and (b) two very resource intensive sub-sectors, beef and pork production. Emergy synthesis is used as the analytical approach for the period 1975–2005 with the results suggesting that not only is more natural capital currently being used within the agricultural sector but the efficiency of the agricultural production has declined considering the increase in transformity during the same period. What is more important though is that agricultural yield is strongly correlated with resource use (quantified as emergy). This finding suggests that sudden changes in resource supply can affect agricultural production and as an extension national food security. Overall the evidence presented in this paper shows that energy security and food security are indeed interconnected and that integrated policy responses will be required if these issues are to be tackled effectively.     

Hydrogen energy storage integrated battery and supercapacitor based hybrid power system: A statistical analysis towards future research directions

Environmentally friendly and pollution-free hydrogen cell, battery and supercapacitor hybrid power system has taken the attention of scientists in recent years. Several notable advancements in energy storage mechanisms with hybrid power systems have been made during the last decade, influencing innovation, research, and the possible direction for improving energy storage technologies. This paper represents a quantitative analysis of all knowledge carriers with mathematical and statistical methods of hydrogen energy storage to establish a hybrid power system. For selecting the top cited papers in this topic, related articles on energy storage mechanisms for hybrid power systems were searched in the Scopus database under specified predetermined parameters. The selection technique of the most cited paper was based on filtered keywords in the hybrid hydrogen energy storage-based hybrid power system and related research during 2008–2021. About 48% of all articles have been published between 2016 and 2019; 21% will have originated from China; and 29% of the papers have used batteries as a form of energy storage in the application of electric vehicles. Most of the articles contain experimental work (25.11%) followed by simulation analysis (25%) and systematic and nonsystematic review (18.75%). Related publications with the most citations were published in 35 different impactful journals from different publishers and nations. This research found that integrating hydrogen energy storage with battery and supercapacitor to establish a hybrid power system has provided valuable insights into the field's progress and development. Moreover, it is a thriving and expanding subject of study. Bibliometric analysis was used to identify the most significant research publications on the subject of hybrid energy storage, mapping the multidisciplinary character, illustrating nature and trends, and outlining areas for further research. The process of collecting, selecting, and analyzing the most cited articles is expected to contribute to a methodical foundation for future developments of hydrogen energy storage systems and provide viable research paths toward attaining a hybrid power system.     

Accounting emergy flows to determine the best production model of a coffee plantation

Cerrado, a savannah region, is Brazil's second largest ecosystem after the Amazon rainforest and is also threatened with imminent destruction. In the present study emergy synthesis was applied to assess the environmental performance of a coffee farm located in Coromandel, Minas Gerais, in the Brazilian Cerrado. The effects of land use on sustainability were evaluated by comparing the emergy indices along ten years in order to assess the energy flows driving the production process, and to determine the best production model combining productivity and environmental performance. The emergy indices are presented as a function of the annual crop. Results show that Santo Inácio farm should produce approximately 20 bags of green coffee per hectare to accomplish its best performance regarding both the production efficiency and the environment. The evaluation of coffee trade complements those obtained by contrasting productivity and environmental performance, and despite of the market prices variation, the optimum interval for Santo Inácio's farm is between 10 and 25 coffee bags/ha.     

Sustainability accounting for the construction and operation of a plant‐scale solar‐biogas heating system based on emergy analysis

Domestic heating systems have long been playing a significant role in China's energy structure. The sustainability of a hybrid solar‐biogas heating system (SBHS) under various feedstock fermentation scenarios was evaluated using emergy analysis. Representative emergy indices such as transformities, emergy yield ratio (EYR), environmental loading ratio (ELR), emergy sustainability index (ESI), ratio of waste treatment (%W), feedback yield ratio (FYR), and emission mitigation intensity (EMI; g/10¹⁰ sej) were selected to evaluate the sustainability performance of different feedstock scenarios including cow dung (CD), swine manure (SM), and poultry manure (PM). The results showed that PM fermentation scenario had greater market competitiveness, lower environmental pressure, better sustainability, and self‐organizing ability than the other two options. However, both the emergy efficiency and the CO₂ emissions mitigation intensity of PM scenario were worse than that of the SM and CD. Moreover, compared with other biogas systems and traditional agricultural systems, the hybrid SBHS was proved to be a promising mode for the treatment of rural manure waste with favorable economic benefits and environmental sustainability.     

Bibliometric analysis of the research on hydrogen economy: An analysis of current findings and roadmap ahead

Based on literature research, this comprehensive analysis of 1275 articles published in the past five decades provides quantitative and objective insight into research trends in the hydrogen economy. Scholars and experts agree that by 2030, hydrogen will play a critical role in energy transition by complementing other renewable energy technologies. We applied indicators such as the Field-Weighted Citation Impact index, cited by and usage count (180 days) to evaluate countries, authors, documents, journals and so on. We also used VOS viewer to visualize the evolving trend using keyword analysis and cluster analysis of documents. Results show that the literature on the hydrogen economy has been recently increasing, particularly from 2016 to 2020. Scopus database was employed to acquire the required data for the study. From preliminary analysis, it was established that from 218 journals, 1275 documents related to hydrogen economy had been published so far. The average publication per year since introducing the term “hydrogen economy” is 6.62 and increasing. The average citation per document is 47.21. There have been 3760 authors so far who have been associated with publications related to a hydrogen economy. Of which 139 authors have written 156 documents individually, and 3621 authors have collaborated to publish 1119 documents, thus forming a collaborative index of 3.24. The International Journal of Hydrogen Energy contributes 40% of the overall publications. In terms of countries, China and United States are the leaders, with 126 papers each. Our analysis shows that the study on hydrogen economy mostly deals with multidisciplinary aspects like hydrogen production, storage, transportation, application, and public policy formulation. We adopted the 180 days usage count offered by the Web of Science database to better understand the research hotspot and evolving trends. It helped us view the existing gaps and potential scope of study that future researchers working on the hydrogen economy can explore. Aspects like pipeline transportation, risk assessment studies, blending, public safety and hazard mitigation can play a vital role in the hydrogen economy research in the future. Cooperation between nations and research institutes should be fostered with cross-disciplinary interchange to boost the hydrogen economy's multidisciplinary growth.     

Grid-connected renewable energy in China: Policies and institutions under gradualism,developmentalism, and socialism

This communication displays some of our on-going research on the incompleteness of China's advances toward “best practice” in policy-making and institution-building for renewables. In particular, this paper: (1) summarizes how Chinese policies and institutions for the deployment of renewable electricity are only partially compliant with what is internationally recognized as “best practice”; and (2) contextualizes Chinese policies and institutions for renewables in the broader picture of China's political economy. Much as a political economy perspective has aided the understanding of why Chinese economic reforms were partial and unique, the said contextualization might help explain why China's policies and institutions for renewables diverge from “best practice”. Further, given that China proved successful in promoting its economic growth with partial and unique reforms, the partiality and uniqueness of its renewables policies and institutions need not impede the rapid development of renewable electricity. This on-going research has so far combined a review of specialized literature and the business press with semi-structured interviews held with relevant actors in policy, business, and research related to renewable energies.