Theory and Application of Emergy Analysis in Arid Region in Northwest China

Through summarizing the research status of emergy analysis at home and abroad,the basic connotation and judgment standard of emergy and indices were introduced in detail. Considering the characteristics of emergy analysis applied to the specific geographic scope in arid region in Northwest China,the problems which should be paid attention to and the corresponding suggestions as well as counter measures were put forward. Finally,trends in the further study of emergy analysis were forecasted.

Emergy Efficiency and Structural Adjustment of Hunan Agro-ecosystem

[Objective] To analyze the efficiency of Hunan agro-ecosystem in 1980- 2010. [Method] This paper adopts the emergy methods to evaluate the emergy input and output. [Result] The growth of total emergy input was mainly caused by the auxiliary factors in this phase. The proportion of the nonrenewable purchased emergy input to the total auxiliary emergy input increased from 21.80% in 1980 to 33.04% in 2010. In 1980-2010 the total emergy output of the system increased by 2.43 times, the proportions of the stock farming emergy output and fishery emergy output to the total emergy output increased sharply, while those of the planting emergy output and forestry emergy output showed a considerable decline. [Conclusion] The emergy yield ratio of this system was improved but its sustainability was worrying.

Emergy-analysis based approaches to develop circular economy in the Three Gorges Reservoir area

The eco-environment and the condition of economic development in the Three Gorges area were evaluated with emergy indices calculated with the statistic data of the years from 1997 to 2005. The rising environmental loading ratio indicates an increasing pressure of economic activities on the environment and the economic development achieved at the cost of over-exploitation of resources and environment deterioration. The net emergy yield ratio implies that the economic system of this area was a self-contained, resource-export-oriented type at a relatively low level of technology. The emergy sustainability index of about 6 implies the economy of this area was under developed but had a potential to grow. According to the results of the emergy analysis, circular economy should be taken as the economic model of this region's development. This economic system should be water-resource-oriented and more open, make combined use of local and extraneous resources, and have an updated systematic structure with emphasis on emergy recirculation.

Emergy evaluation of the environment and economy of Hong Kong

An environment-economy systems analysis of Hong Kong has been carried out using a newmeasure emergy for evaluating its environmental resource basis and economy as well as its international e-conomic relations for recommending a sustainable development. Emergy is the total energy uf one kind re-quired directly and indirectly to form a resource, product or service. It provides a common basis for mea-surement of the value of environment and economy.A preliminary analysis of emergy contributions supporting the system of Hong Kong is presented inthis paper.

Eco-economic evolution, emergy evaluation and policy options for the sustainable development of Tibet

As economies and ecological support systems become more interdependent, new disciplines are needed to 'bridge the gap' of understanding between societies and nature. It is now clear that neither ecology nor economics alone can address the problems of our global commons. New measures of wealth, of value, of contributions and production are needed that acknowledge the 'natural capital' and 'ecosystem services' provided from healthy environments. A new interface is now being recognized termed 'eco-economics'. It is an ambitious and necessary attempt to understand the affairs of humanity and nature as a single, interdependent system. New tools are being invested to measure wealth. services and production fairly and equitably. In this report we use systems analysis approach to study the combined ecological-economic system of Tibet We use an alternative measure of value, based on real contributions to system performance, termed EMERGY, spelt with an 'M'. It is an accounting unit of total contributions, direct and indirect. used in generating a product or service. It is a concept derived from understanding whole systems, their interactions and interdependence, and the resources driving and maintaining them. This broader approach will help us to investigate Tibetan resources utilization and potentialities and exchange. Emergy analysis allows comparison and incroporation of environmental costs and benefits with variables of traditional economic costs and benefits to provide a more comprehensive perspective for public policy directives. Through this research, we think: 1) China has made a great effort in making Tibet develop from a closed regional system to a more and more opened regional system which is very important to the sustainable development of Tibet. 2) The increase of economic development and population growth has a close relationship with the total emergy storage and use in transportation. Education in modern science and technology increased the shared emergy of Tibetans to modern science and technology and stimulated the process of matching material and energy imports from outside with local resources. 3) There is great potential to develop hydropower and geothermal reserves that may stimulate not only economic development but also the better use of environment. 4) The better trained population can increase the empower of Tibet eco-economic system. Future development needs all kinds of talent exchanges with the outside system to develop education. 3) Compared with the Tibet economic system, Taiwan economic system is much more competitive. GNP and emergy use are very useful functions for comparing the competitive power of different ecological economic systems.

A joint use of emergy evaluation, carbon footprint and economic analysis for sustainability assessment of grain system in China during 2000–2015

The rapid growth of grain yield in China accelerates a discussion on whether the grain system in China is sustainable. To answer the question, a comprehensive assessment from economic and environmental points is necessary. This study jointly used economic analysis(ECA), emergy evaluation(EME) and carbon footprint(CF) to analyze the environmental and economic sustainability of the grain production system in China based on the national statistical data during 2000–2015. Results showed that the costs of maize, wheat, rice and soybean had increased by 252-346% from 2000 to 2015, causing the lower profit of grain system in recent years. The situation resulted in a serious problem on economic sustainability of grain system in China. Meanwhile, the emergy sustainability index(ESI) of maize, wheat, rice and soybean systems were increasing during 2000–2015, and the CF on unit yield of the crops had been reduced by 10-30% in the study period. The results reflected the improved environmental sustainability of grain system in China during 2000–2015. Nevertheless, the emergy flow of industrial inputs for the crops were increased by 4-22% in the study period, and the CF from the inputs presented a growth rate of 16-23% as well during the same period. The results implied that the grain system in China was relying more on fossil-based inputs. Finally, according to the key points of cost, emergy and CF, we suggest that improving labor efficiency, advanced agricultural practices and optimizing cropping pattern will be effective ways to further improve the economic and environmental sustainability of grain system in China.

New emergy indices for sustainable development

The emergy indices for the evaluation of system's sustainable development ability were studied. Results indicated that the emergy indices are simplified and merged, and a new emergy index for sustainable development(EISD) is deduced. Employing EISD, two cases are conducted. The first one is to compare three different dike pond agro ecological engineering modes, which are: melon melon cabbage four domestic fishes(mode Ⅰ), melon melon cabbage pig four domestic fishes (mode Ⅱ) and melon melon cabbage pig four domestic fishes combined with Siniperca chuatsi B. ( mode Ⅲ). The result is that the EISD of mode Ⅰ is 0.53. ModeⅡ's EISD is 5.26 times of mode Ⅰ, and mode Ⅲ's EISD is 6.83 times of mode Ⅰ. The second one is to evaluate the development of Zhongshan City, Pearl Delta, during 1996 to 2000. The result indicated that the EISD of Zhongshan had appreciably declined from 1996 to 1998, and quickly improved from 1998 to 2000, partly because of its environment protection and product construction. Both of the two cases studies showed that EISD can assessment the sustainable development ability more roundly, with the consideration of environmental impact and social\|economic effect at the same time.

Two Village Ecosystems in the Upper Minjiang River, China: A Comparison of Emergy Flow

By using the concept of emergy and method of emergy analysis, this paper has studied two mountain settlement (village) ecosystems in two aspects: input and output of energy in the agro-systems and the use of fuel energy. The result reveals that the settlement agro-system in the valley of Minjiang River is better in both structure and function than that at the so-called half-high mountain. The former one is higher than the latter one regarding such indices as emergy yield ratio, labor productivity of emergy and emergy sustainable index, but lower than the latter one regarding environmental loading ratio. In terms of fuel emergy, the settlement in the valley enjoys more diversified sources and is less depending on bio-energy while the settlement at the half-high mountain has only one source (i. e. fuel wood) , much depending on bio-energy, may exert a greater pressure on environment.

Emergy-based study on eco-economic system of arid and semi-arid region:a case of Gansu province,China

Taking Gansu province as a model case,this study provides an integrated analysis on the eco-economic system of arid and semi-arid region based on emergy synthesis theory. Through calculating the values of renewable emergy flow,non-renewable resources,imported emergy,exported emergy,waste emergy,and total emergy during the period of 1978-2007,the performance of Gansu eco-economic system was analyzed. The results indicated that the renewable emergy flow within the province basically remained steady state which was estimated at 2.99×1022 solar emjoules (sej) from 1978 to 2007. The imported emergy and exported emergy were estimated at 3.75×1017 sej and 2.99×1020 sej in 1978 and increased to 1.07×1022 sej and 1.44×1022 sej respectively in 2007. The nonrenewable emergy flow was estimated at 1.62×1022 sej and increased to 1.85×1023 sej,with annual growth rate of 8.7%,while the estimated total emergy was 4.58×1022 sej in 1978 and increased to 2.11×1023 sej in 2007,with annual growth rate of 5.41%. Our results indicate a deteriorate situation between economic development and environmental protection in the region. The rapid economic growth in the past thirty years was based on a great consumption of nonrenewable resource and caused continuous decrease in the capacity of sustainable development. The environmental loading ratio was 0.53 in 1978,increased to 6.06 in 2007,indicating a rapid degradation of the regional environment quality. We calculated that the actual population was 1.53 times the renewable resource population in 1978,increased to 7.06 times in 2007. During the period of 1978-2007,the emergy rose from 2.45×1015 sej/(capita·a) to 8.07×1015 sej/(capita·a). Our analysis revealed that the emergy density presented a trend of gradual increase,and then the emergy currency ratio in Gansu decreased from 7.08×1013 sej/Chinese Yuan to 7.82×1012 sej/Chinese Yuan.

Sustainability Evaluation of Different Systems for Sea Cucumber(Apostichopus japonicus) Farming Based on Emergy Theory

Emergy analysis is effective for analyzing ecological economic systems. However, the accuracy of the approach is af- fected by the diversity of economic level, meteorological and hydrological parameters in different regions. The present study evalu- ated the economic benefits, environmental impact, and sustainability of indoor, semi-intensive and extensive farming systems of sea cucumber （Apostichopus japonicus） in the same region. The results showed that A. japonicus indoor farming system was high in input and output （yield） whereas pond extensive farming system was low in input and output. The output/input ratio of indoor fann- ing system was lower than that of pond extensive farming system, and the output/input ratio of semi-intensive farming system fell in between them. The environmental loading ratio of A.japonicus extensive fanning system was lower than that of indoor farming sys- tem. In addition, the emergy yield and emergy exchange ratios, and emergy sustainability and emergy indexes for sustainable devel- opment were higher in extensive farming system than those in indoor farming system. These results indicated that the current exten- sive farming system exerted fewer negative influences on the environment, made more efficient use of available resources, and met more sustainable development requirements than the indoor farming system. A. japonicus farming systems showed more emergy benefits than fish fanning systems. The pond fanning systems ofA. japonicus exploited more free local environmental resources for production, caused less potential pressure on the local environment, and achieved higher sustainability than indoor farming system.

EMERGY ANALYSIS OF GRAIN PRODUCTION SYSTEM IN JIANGSU AND SHAANXI PROVINCES

Efficiency and sustainability of grain production are now important in China. In this study, the grain production systems of Jiangsu and Shaanxi Provinces were compared, to analyze their efficiency and sustainability in terms of utilization of natural resources, inputs of purchased energy and materials, and outputs. Flows of energy and materials between environment and human society were identified, and the natural and human work involved in generating inputs as materials or energy were valued in terms of equivalent amount of solar energy required for their production using emergy method. The results showed environmental resources were continually playing a less important role in the systems, when inorganic subsidiary emergy inputs increased drastically while organic ones decreased or increased little. Deterioration of input emergy structure affected the systems′ efficiency and sustainability,resulting in emergy investment ratios and environmental loading ratios increasing while yield ratios and sustainability indices decreasing. In general, efficiency and sustainability of grain production in Jiangsu are worse than those in Shaanxi. This analysis also suggested that inorganic subsidiary emergy should be introduced properly, and peasants in Jiangsu should utilize natural conditions wisely while those in Shaanxi pay enough attention to soil and surface water conservation.

Urban Metabolism Based on Emergy and Slack Based Model: A Case Study of Beijing, China

The key to studying urban sustainable development depends on quantifying stores, efficiencies of urban metabolisms and capturing urban metabolisms′ mechanisms. This paper builds up the metabolic emergy account and quantifies some important concepts of emergy stores. Emphasis is placed on the urban metabolic model based on the slack based model(SBM) method to measure urban metabolic efficiencies. Urban metabolic mechanisms are discussed by using the regression method. By integrating these models, this paper analyzes the urban metabolic development in Beijing from 2001 to 2010. We conclude that the metabolic emergy stores of Beijing increased significantly from 2001 to 2010, with the emergy imported accounting for most of the increase. The metabolic efficiencies in Beijing have improved since the 2008 Olympic Games. The population, economic growth, industrial structures, and environmental governance positively affect the overall urban metabolism, while the land expansion, urbanization and environmentally technical levels hinder the improving of urban metabolic efficiencies. The SBM metabolic method and the regression model based on the emergy analysis provide insights into the urban metabolic efficiencies and the mechanism. They can promote to integrate such concepts into their sustainability analyses and policy decisions.

Emergy analysis of paddy farming in Hunan Province, China： A new perspective on sustainable development of agriculture

The multi-functionality of paddy farming has become a hot issue recently. Paddy farming provides numerous ecosystem services that are crucial to human well-being. However, evaluation of the contribution of paddy farming to human well-being usually focus on its economic value, while its non-market services are usually ignored. Only evaluating the market profits or market relative benefits cannot reflect comprehensively the contribution of paddy farming to people＇s well-being. This will affect people＇s choices for or against paddy farming activities and people＇s opt for invest or not invest in it. A comprehensive evaluation of paddy farming can provide an important reference for the government and society to conserve the multi-functionality of paddy farming and achieve sustainable development. To this end, this paper reports a case evaluation of paddy farming in Hunan, the largest rice producing as well as rice yield province in China, and uses emergy theory to make a comprehensive evaluation for paddy farming. The emergy evaluation results of the paddy ecosystem in Hunan are as follows： in 2010, the input emergy of the paddy ecosystem in Hunan is 2.51E＋22 sej and the output emergy is 6.31E＋22sej. For the input emergy, the part from natural resources is 1.96E＋21 sej and the part from human society is 2.32E＋22sej; for the output emergy, the part from products is 2.22E＋22 sej, the part from impositive externality is 4.16E＋22 sej and the part from negative externality is –7.41E＋20 sej. Taking the non-market outputs into consideration, the gains from the human economic society＇s 1 $ input in paddy farming, emergy sustainability index（ESI） and emergy profit rate are respectively 2.73 $, 3.53 and 151.31%. If the evaluation leave out the non-market output, the three indexes are only 0.96 $,1.24 and 30.67%. The research results show that non-market services of paddy farming contribute significantly to human well-being. Therefore, in order to protect the multi-functionality of paddy farming and achieve the sustainable management,the government should take reasonable measures and make incentive plans.

Emergy Analysis of Agro-ecosystem in Poyang Lake Area

By using emergy analysis theory and methods, we conduct quantitative analysis on the input and output of emergy, and sustainable development of agro-ecological system in Poyang Lake Area. The results show that compared with the national average, the environmental loading ratio is relatively low in this area; the net emergy yield rate is high; the sustainable development ability is strong. Finally according to the results of emergy analysis, corresponding countermeasures are put forward as follows: develop agriculture based on the existing rich natural resources; increase technological inputs; develop circular agriculture; promote sustainable agricultural development.

An emergy evaluation of the seven years’development of Qianyanzhou ecological experimental station

An emergy (spelled with an “m”) evaluation of Qianyanzhou ecological station was performed in order to study its progress during 7 years' development, using changes of emergy inputs and outputs Emergy indices of Qianyanzhou were evaluated and compared with those from other countries The comparison showed that Qianyanzhou may be developing optimum use of its natural resources

Sustainable Utilization of Agricultural Land in Chengdu Metropolitan Area Based on Emergy Analysis

[Objectives]This study aimed to analyze the sustainable use of agricultural land in the Chengdu metropolitan area from 2006 to 2016.[Methods]Using Odum's emergy theory,an index system was constructed to evaluate the sustainable use of agricultural land,including total emergy input-output ratio,industrial emergy input-output ratio,environmental load index and sustainable use index of agricultural land based on emergy,to reflect the sustainable use of agricultural land in the Chengdu metropolitan area.The data base was a unified standard that was converted from various types of energy stored and flowing in the agricultural land system of the Chengdu metropolitan area,that is,emergy.[Results]From 2006 to 2016,the total emergy input-output ratio of agricultural land in the metropolitan area fluctuated and decreased,lower than the national average.The industrial emergy input-output ratio was generally in a fluctuating downward trend.The environmental load index of agricultural land in the metropolitan area was lower than the national average.However,it has been on the rise since 2012.During the corresponding period,the sustainable use index of the region also showed a downward trend.[Conclusions]The utilization rate of emergy in this area was low.The dependence of industrial emergy input-output ratio on industrial subsidiary energy and the degree of agricultural mechanization are constantly improving.The environmental resources in this area still have room for accommodation and have not been fully utilized.The sustainable use of agricultural land has been declining.

Emergy evaluation of the artificial forest ecosystems in the watershed of Miyun Reservoir:a case study for ecosystems valuation and environmental management

To build the artificial forest ecosystem is the major eco-economic development model in the watershed of Miyun Reservoir. It is very important to evaluate the benefits of those ecosystems. Emergy theories are very helpful for us to establish a science-based assessment framework. Emergy evaluation of the artificial forest ecosystems in the watershed of Miyun Reservoir is used to asses the relative values of several ecological functions (sometimes called ecosystem services) and main ecosystem storages (sometimes called natural capital). The main driving energies, internal processes and storages are evaluated. The main functions, including transpiration, GPP and infiltration, are evaluated, which are 609em$/ha/yr, 6,245em$/ha/yr and 340em$/ha/yr respectively. The total values of major environmental services are 4,683em$/ha/yr in the artificial forest ecosystem. The main storages of natural capital including live biomass, soil moisture, organic matter, underground water and landform are estimated, which are 112,028em$/ha, 9em$/ha, 40,718em$/ha, 34em$/ha and 6,400,514em$/ha respectively. The largest value is landform, which accounts for 97.7% of these calculated total emdollar values. The concept of replacement value is explored using the emergy values of both ecosystem services and natural capital. The total calculated replacement values are 302,160em$/ha.

Emergy evaluation of aromatics production from methanol and naphtha

Aromatics are traditionally produced by the catalytic reforming of naphtha.However,with the demand of aromatics increasing and the reserves of petroleum resources declining,measures should be made to reduce the dependence of aromatics production on petroleum resources.Methanol-to-aromatics is proved to be an effective way to replace traditional naphtha-to-aromatics path.In order to compare the economic and environmental performance of aromatics production from naphtha and methanol,this paper carries out an emergy evaluation for each system by sorting out the simulation and literature data.Based on the emergy data collected,the emergy indices of each system are calculated.The results show that the sustainabilities of methanol-to-aromatics systems are higher than that of the naphtha-toaromatics system,indicating the advantages of aromatics production from methanol.Among the methanol-to-aromatics systems,the aromatics from biomass-methanol system has the highest sustainability,indicating that the biomass based methanol-to-aromatics system is worth promoting.The sustainability indexes of methanol-to-aromatics systems based on coal and coke oven gas are less than 1,which means unsustainable.Meanwhile,the sustainability of natural gas based system is slightly higher than 1.The economic and environmental benefits of these systems can be optimized by improving resource utilization and reducing investment costs.Furthermore,the combination of different raw materials for methanol production should be considered.

Comprehensive emergy evaluation and optimization of corn straw power generation system: a case study

Biomass energy has become an important measure to alleviate ecological environment security and energy supply security in China.Emergy accounting method is used to analyze and evaluate economy,environment,and sustainability of corn straw generation system,which includes corn planting subsystem,collection and transportation subsystem,and corn straw power generation subsystem.The key substances that need to be optimized in the system are identified by using sensitivity analysis.Based on the position of key substances in the system,emergy accounting optimization methodology is conducted.Corresponding optimization design scheme is proposed based on the '3R' (reduce,reuse,and recycle) principle of circular economy.Current study shows that emergy yield ratio,emergy investment ratio,environmental loading ratio,and emergy sustainability index of the corn straw power generation system are 3.69,2.68,1.61,and 2.29,respectively,which are better than wind power generation system and thermal power generation system.In addition,it is proposed that the fertilizer alternative plan and the transportation redesign plan can replace 50,000 tons potash and reduce equipment resources by 20% and energy resources input by 30%.Economy and sustainable development of the system is significantly improved.The optimization design method based on the '3R' principle proposed in this paper can provide a useful reference for the research in the field of resource recycling.

Emergy Evaluation of a Village Ecosystem in Wolong Nature Reserve in China

Due to historic reasons, there are several human settlements in nature reserves and national parks, which may constitute a threat to biodiversity. Establishment of nature reserves may however generate constraints for development of local communities residing in these reserves. The village ecosystem of Zhuanjinglou Village in Wolong Nature Reserve includes population, farming and livestock (domestic and alpine) and forest ecosystem. An emergy analysis of agro-ecosystem (including the farming and livestock ecosystem) and energy consumption in Zhuanjinglou Village indicates that livestock ecosystem plays an important role in village ecosystem, which may be the source of great pressure on the state of the local environment. The increasing ratio of electricity in energy consumption may play a positive role for environmental conservation. Despite some successful experiences, there are some remaining issues that need to be addressed in the ecological rehabilitation of the village ecosystem.