Emergy Sustainability Index Research Articles

An Improved Emergy Analysis of the Environmental and Economic Benefits of Reclaimed Water Reuse System

Reclaimed water, a nontraditional water source, has become a desirable choice for meeting the increasing demand in areas with water shortages. However, the environmental and economic benefits of reclaimed water reuse systems (RWRSs) are unclear. Therefore, we conducted this study to assess the environmental performance of RWRSs based on emergy analysis. Notably, the emergy index system was improved by incorporating the environmental impacts of air emissions. The results show that the improved emergy indicator system was more rigorous than the traditional emergy index system. The environmental loading ratio and the emergy sustainability index of the studied system based on an improved emergy index system was 0.202 and 30.01, respectively. The environmental economic value was 3.52 × 1020 sej/y. The results show that the RWRS has good sustainability, and high environmental and economic benefits. Compared with two other RWRSs (Scenario A in Zhengzhou City and Scenario B in Chongqing City) and one seawater desalination system (Scenario C in Qingdao City), it is found that RWRSs are preferred as a way to obtain water resources over seawater desalination under the same water quality conditions. It is also important to select an appropriate treatment process according to the raw water quality and reclaimed water use in the practical application.

Multi-Criteria Assessment of the Economic and Environmental Sustainability Characteristics of Intermediate Wheatgrass Grown as a Dual-Purpose Grain and Forage Crop

Kernza® intermediate wheatgrass [IWG; Thinopyrum intermedium (Host) Barkworth & Dewey] is a novel perennial cool-season grass that is being bred for use as a dual-purpose grain and forage crop. The environmental benefits of perennial agriculture have motivated the development of IWG cropping systems and markets for perennial grain food products made with Kernza, but the economic viability and environmental impact of IWG remain uncertain. In this study, we compared three-year cycles of five organic grain production systems: an IWG monoculture, IWG intercropped with medium red clover, a continuous winter wheat monoculture, a wheat–red clover intercrop, and a corn–soybean–spelt rotation. Economic and environmental impacts of each cropping system were assessed using enterprise budgets, energy use, greenhouse gas (GHG) emissions, and emergy indices as indicators. Grain and biomass yields and values for production inputs used in these analyses were obtained from experimental data and management records from two separate field experiments conducted in New York State, USA. Grain yield of IWG averaged 478 kg ha−1 yr−1 over three years, equaling approximately 17% of winter wheat grain yield (2807 kg ha−1 yr−1) over the same period. In contrast, total forage harvested averaged 6438 kg ha−1 yr−1 from the IWG systems, approximately 160% that of the wheat systems (4024 kg ha−1 yr−1). Low grain yield of IWG greatly impacted economic indicators, with break-even farm gate prices for Kernza grain calculated to be 23% greater than the current price of organic winter wheat in New York. Energy use and GHG emissions from the IWG systems were similar to the annual systems when allocated per hectare of production area but were much greater when allocated per kg of grain produced and much lower when allocated per kg of biomass harvested inclusive of hay and straw. Emergy sustainability indices were favorable for the IWG systems due to lower estimated soil erosion and fewer external inputs over the three-year crop cycle. The results show that the sustainability of IWG production is highly dependent on how the hay or straw co-product is used and the extent to which external inputs can be substituted with locally available renewable resources. Integrated crop–livestock systems appear to be a viable scenario for the adoption of IWG as a dual-use perennial grain and forage crop.

Environmental Accounting of the Yellow-Tail Lambari Aquaculture: Sustainability of Rural Freshwater Pond Systems

Freshwater pond aquaculture is the prevailing fish culture system worldwide, especially in developing countries. The sustainability of such systems has not been assessed and it can be improved based on suitable scientific analyses. In the present study, we apply the emergy synthesis to assess the sustainability of lambari aquaculture, used as a model of freshwater pond monoculture in Brazil, to identify the key practices, and to propose changes to improve them towards sustainability. As a study model, nine semi-intensive lambari farms operating at three levels of management were evaluated: low (LC), moderate (MC) and high (HC) control. Results showed that the main inputs for LC were services (27–46%), feed (7–39%) and water (15–21%), while for the MC and HC farms, they were feed (35–49% and 17–48%, respectively) and services (33–39% and 26–36%, respectively). All farms required more than 60% of their emergy from purchased inputs, resulting in low emergy sustainability index (ESI = 0.1–0.5). Increasing juvenile productivity, using superficial water instead of springwater, controlling pond fertilization and replacing animal protein in diet composition by vegetable sources can lead systems to higher efficiency and resilience, increasing sustainability.

Emergy-based sustainability analysis of bioenergy production from marginal and degraded lands of India

Analysing the sustainability of cultivating biomass and biofuel plant species on marginal and degraded lands is essential for assessing the socio-economic and environmental perspectives. Various approaches have been suggested for the sustainability analyses, such as life cycle assessment, footprint analysis, multi-criteria decision analysis, and emergy analysis. Among these approaches, the emergy analysis is one of the most direct methods to assess the system's sustainability. The present article was aimed to perform the emergy analysis to quantify the ecological impacts, bioenergy potential, socio-economic efficiency, and the sustainability of the bioenergy production systems. The emergy-based sustainability analysis was conducted for the Soyabean-, Pongamia-, Jatropha-based biodiesel and Tectona-based biomass production systems from the Indian marginal and degraded lands. Results depicted that under a set of system boundaries for each plant species, total emergy output (U) of 1000 kg biodiesel (biomass in case of Tectona) was calculated to be 0.99E+16 for Soyabean-; 1.01E+16 for Pongamia-; 1.33E+16 for Jatropha- and 0.72E+16 sej for Tectona-based bioenergy production options. Emergy of fuels dominated the economic inflows (F) (32.53%) under the Soyabean-based option making it the second system to represent a greater environmental load ratio (ELR) of 17.98. Furthermore, the emergy of water resources was dominated under F in other studied bioenergy options, i.e., 38.08% of F in Pongamia-, 44.54% in Jatropha-, and 66.52% in Tectona-based systems. The emergy sustainability indices (ESI) of 0.06, 1.04, 0.34, and 0.02 were found for Soyabean-, Pongamia-, Jatropha-, Tectona-based bioenergy production systems, respectively. Sensitivity analysis further suggested that a decrease of 3.5% in F resulted in a 10.02% increase of ESI for the Pongamia-based option. Pongamia-based options depicted an ESI > 1, which could be considered to have a sustainable contribution to the economy for medium periods. The estimated ESIs were fundamentally low because the systems were dependent mainly on the F.

Comprehensive analysis of industrial-scale heating plants based on different biomass slow pyrolysis technologies: Product property, energy balance, and ecological impact

Slow pyrolysis poly-generation technology for rural heating using agroforest residues has reached the stage of industrial demonstration application in China. Comprehensive assessment of technical characteristics and technical adaptability is essential as further industrialization development requires related plants to be sustainable and replicable. In this study, three typical technical processes and application models are discussed; namely, poly-generation for syngas and char using a rotary kiln (SCRK), poly-generation for syngas and char using a vertical kiln (SCVK), and poly-generation for hot water and char using a chain grate furnace (HCCF). The technical characteristics, adaptability to raw materials, product property, energy balance, and ecological impact were systematically analyzed by an empirical analysis based on industrial-scale project data. The SCRK was advantageous in terms of product quality and yield of char; the low heating value (LHV) of syngas exceeded 17.3 MJ/m 3 , which was approximately thrice that of the other two technical processes. The energy conversion efficiency of the SCVK was 76.8%, that is, approximately 4.0–5.7 percentage points higher than that of the HCCF and SCRK. The emergy sustainability indices of SCRK, SCVK, and HCCF, as ecological indicators, were 31.2, 21.4, and 24.5, respectively. The above results indicate that the heating plants based on biomass slow pyrolysis have promising application prospects. The technology promotion path was discussed by matching production situations, market demands, and technical characteristics based on a technical evaluation radar chart. Some targeted suggestions were proposed for the industrial application of different biomass slow pyrolysis poly-generation technologies. This study provides a reference for industrialization development of biomass slow pyrolysis technologies for rural heating. • Agroforest residues were used for slow pyrolysis poly-generation for rural heating. • Product property, energy balance, and ecological impact were analyzed. • All three technologies had sustainable development capabilities. • Rotary kiln had higher product quality and char yield rate than the others.

Assessing the sustainability of ecosystems over fourteen years of cultivation in Longnan City of China based on emergy analysis method

Currently, the contradiction between the limited resources of China's cultivated ecosystems and population growth is becoming increasingly evident, and the negative impacts on the environment and human activities need to be curbed. Therefore, it is crucial to quantify the sustainability of cultivated ecosystems and determine these driving factors that affect their development. This study used the emergy method to quantify the input/output flow and sustainable development of the cultivated land ecosystem in Longnan City, combined with the logarithmic mean divisia index decomposition analysis (LMDI) method to evaluate the driving factors of sustainable development in the region. The results demonstrate that from 2004 to 2017, the total emergy input and output of Longnan City showed an upward trend, and non-renewable resources (N) were always in a dominant state in the total emergy (T) input, and their proportion rose from 59.69% to 66.92%. The emergy sustainability index (ESI) is less than 1, and the environmental pressure of the system is relatively higher. Comprehensive emergy production ratio (EPR), emergy investment ratio (EIR), the renewable fraction (R%), emergy yield ratio (EYR) and environmental load ratio (ELR), showed that the agricultural ecological economy in Longnan still has great development potential, and clean energy should be developed as far as possible to replace fossil fuels in future planning. LMDI results showed that the intensity factor ΔY′A is the main driving factor for the positive development of ESI. The government's ecological protection requirements can reduce waste emissions through reasonable farming system and advocating the use of organic fertilizer, so as to achieve the purpose of improving crop yield. Vigorous development of green ecological agricultural production patterns can improve the sustainability of arable ecosystems. This study can provide a theoretical basis for the sustainable development of cultivated ecosystems and the formulation of related agricultural production measures.

Optimized ratoon rice system to sustain cleaner food production in Jianghan Plain, China: a comprehensive emergy assessment.

Ratoon rice (RR) is regarded as a labor-saving and efficient approach to rice cultivation; however, sub-optimal production techniques (fertilization, irrigation, harvesting) may lead to serious environmental problems and unsustainable agriculture. In this study, emergy analysis was combined with indicators of soil fertility, global warming potential (GWP), and profitability to comprehensively assess the sustainability performance of three cultivation modes: (i) traditional farm practice (TRA), (ii) optimized mode (OPT), and (iii) OPT plus green manure planting (OPTM). Over 2years, compared with the TRA mode, OPT and OPTM modes increased total rice yield by 10% and 19% on average and improved profit by 233.7 and 456.5 Yuan ha-1, respectively. Single emergy analysis results showed that, compared with the TRA mode, OPT and OPTM (2-year average value) modes increased production efficiency by 10% and 8%, reduced renewable fraction and emergy sustainability index by 14-19% and 18-23%, respectively, and increased environmental loading ratio by 31% and 22%. Multiple EMA analysis results showed that, compared with the TRA mode, OPT and OPTM (2-year average value) modes reduced UEVNmin by 23% and 21% and increased UEVGWP 32% and 51%, respectively. The UEVTotal revenue and UEVBenefit of OPT and OPTM increased by 8-29% and 4-37%, respectively, compared with TRA mode. The comprehensive assessment indicated that, despite OPT and OPTM modes have a range of improvements and dis-improvements versus the TRA mode, OPTM was the more sustainable mode of RR production overall. However, some sustainability indicators remained poor, and there remains scope for further optimization via, e.g., precision application of enhanced-efficiency fertilizers, application of a straw-decomposing inoculant to improve soil fertility, and use of new improved rice varieties with high regenerative ability to improve the yield of ratoon crops.

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%.

The sustainability of staple crops in China can be substantially improved through localized strategies

China's staple crop systems face great challenges to reduce the intensive use of agrochemicals and associated pollution while ensuring food security. Given the large variation in resource endowment, climatic and socioeconomic conditions, improving the sustainability of staple crops requires localized strategies. What strategies to pursue at local levels and to what extent they can improve crop sustainability remain unclear. Here, we present the first crop-specific county-level sustainability assessment of China's staple crops (wheat, maize, and rice) and their potentials for improvement using emergy analysis. Results show that the current mean emergy sustainability index of wheat, maize and rice is relatively low (i.e., at 2.35, 2.45, 1.94, respectively), indicating the production system of staple crops in China is relatively vigor but has still a large potential for improvement. Their sustainability is driven primarily by crop yield, nitrogen and phosphorus fertilizer use, and thus can be notably improved by such strategies as closing yield and nutrient-use efficiency gaps. Staple crops sustainability at the county level exhibits a large spatial heterogeneity, and the top 25% counties of emergy sustainability are mainly concentrated in the northern plain (for wheat), in the southwest regions and the central region (for maize), and in the southwest regions (for rice). More importantly, the county-level improvement potential shows a large spatial variation between strategies, suggesting that different regions would benefit more from different strategies. With the optimal strategy suited to each region, the mean emergy sustainability index of wheat, maize, and rice would increase by 35.6%, 40.5%, 26.6% compared with the current level, respectively. Overall, our study based on high-solution spatially-explicit analyses can inform farmers and policy makers on sustainable agricultural management, and provide a reference for other developing countries facing similar challenges. The comprehensive and detailed county-level crop database we have compiled can also be used broadly for analyses of China's agricultural pollution and food security.

Regional sustainability assessment using emergy accounting approach: The case of Nepal in South Asia

Emergy accounting is an environmental assessment tool that accounts for all the energy pathways in production systems. In this regard, the System Thinking Experimental Learning Laboratory Animation (STELLA) with emergy model are used for a retrospective and prospective assessments. Nepal, a country having a relatively small economy but with faster recent growth as well as its geographical position and potentially high vulnerability to climate change was analyzed as a case study using data for 1998–2015 (retrospective) and 2015–2040 (prospective). As per our results, the rising use of non-renewable resources and decreasing use of locally extracted materials caused higher environmental load and reduced emergy sustainability scores. In addition, the effect of natural disasters, such as the Gorkha earthquake, on environmental performance of Nepal was analyzed by emergy accounting. Futuristic emergy analysis for 2015–2040 showed that total and non-renewable emergy would rise considerably, and the emergy sustainability index could further decrease by 33%. Based on these findings, small yet rapidly growing economies, such as Nepal, could improve their environmental management by reducing the material trade deficit (i.e., by increasing domestic material extraction and reducing imports of non-renewable resources), minimizing the use of non-renewables, improving soil fertility, and promoting renewable resource consumption.

Economic and Environmental Assessment Using Emergy of Sheep Production in Brazil

This study aimed to evaluate the economic and environmental performance of a Brazilian sheep production system (in the São José do Rio Preto (SJRP) region). The cost of production and the emergy indicators were calculated, and compared with other scientific results. The study was divided into three stages: (i) construction of the conceptual model; (ii) transformation of all resources and stocks by unit emergy value; and (iii) analysis of emergy indices. For emergy analysis, imported purchased inputs (P) represented 59.84% of all emergy, in which soy and corn contributed 16.14% and 11.38%, respectively. These inputs also contributed significantly to the economic cost of production as 14.63% and 12.55% of the total cost, respectively. Compared to other production systems, the SJRP system presented a lower emergy production rate and a higher environmental load rate, reducing the emergy sustainability index. In addition, it had the highest level of investment in emergy, suggesting that its sustainability is inferior to other referenced production systems. However, the SJRP system had the lowest emergy exchange ratio, indicating that this system is the closest to a fair price. In conclusion, the system must be reconsidered to become more sustainable; mainly with regard to the confinement of lambs that consume large amounts of concentrate (corn and soybean) from outside the system.

Evaluation of suppliers in the tannery industry based on emergy accounting analysis: implications for resource conservation in emerging economies

ABSTRACT Emergy Accounting (EMA) has gained attention in recent times as an environmental accounting tool. So far, it has been used for analysis at national and regional levels; however, the EMA has not been utilised in a business performance analysis context. When used in a business context, EMA reveals the interface between industrial activity and the environment. EMA analysis can provide opportunities in measuring the social, economic, and environmental performance of the industry in a sustainability context. Unlike other evaluation methods, which are ‘demand-side’ or ‘user-side’ concerned, EMA analysis is a ‘donor-side’ approach. This research work illustrates the selection of suppliers based on the amount of emergy consumption. Emergy indicators, such as Emergy Yield Ratio (EYR), Emergy Sustainability Index (ESI), Environmental Loading Ratio (ELR), Emergy Self-support Ratio (ESR), Renewability percent (%R), Emergy flow Density (ED), and Emergy Investment Ratio (EIR) are estimated. The results show that there is enough room for improving emergy performance in the tannery industry. The result also highlights a significant variance in the input of indigenous renewable and non-renewable resources and imported resources among the investigated tanneries. Based on the outcomes, the study provides insights on the industries’ consumption of renewable and non-renewable resources.

The Environmental-Economic Performance of a Poblano Family Milpa System: An Emergy Evaluation

The family milpa system (FMS) is of great importance to food security and the livelihoods of rural families in Mexico. However, the performance of the system can be compromised due to inappropriate agricultural practices. Therefore, a suitable evaluation strategy is required to identify the best management of resources. Nonetheless, at present, there is no holistic understanding around the nature–society interface that allows us to predict the global behavior of the FMS. Thus, this study assesses the global performance of a Poblano FMS through emergy-based indices. The emergy evaluation was carried out by accounting for the available energy of different qualities used in the system, which were subsequently converted to one kind of energy (solar emjoules). The percentage of renewable emergy (%Ren) used in the system was 72.16%. The emergy self-support ratio (ESR) showed that 74% of the emergy used came from free local resources. The emergy investment ratio (EIR) of 0.36 indicated that the emergy use was efficient. The emergy yield ratio (EYR) was 3.78, which in terms of net emergy (NE), was equivalent to a gain of 1.35 × 1016 sej ha−1 y−1. The environmental loading ratio (ELR) was 0.39, which indicated a low potential environmental impact. The emergy sustainability index (ESI) was high (9.80) compared to other agricultural systems. The performance of the FMS is superior compared to other agricultural systems, including ecologic and recycling systems. However, the use of resources is not optimum and needs to be improved to reach maximum empower.

An integrated approach to analyzing the effect of biofloc and probiotic technologies on sustainability and food safety in shrimp farming systems

Aquaculture is essential to meet the demand for seafood due to the decrease in fish stocks caused by predatory fishing. Even though aquaculture is a sustainable seafood option, shrimp farming is often associated with eutrophication, mangrove destruction, disease propagation, and biodiversity reduction in coastal regions. These environmental problems generate financial losses, and to minimize the impacts on shrimp farms, producers use bioflocs technology and commercial probiotics to improve water quality and be more productive. This study uses emergy and microbiology analyses to estimate the improvement of microorganisms on the sustainability and food safety indicators of three commercial farms that use probiotic and bioflocs technology to produce shrimp. The first farm had 385 ha, a conventional system, stocked 10 shrimp/m2 and used probiotics. It had the best transformity (Tr = 10.6) and emergy yield ratio (EYR = 1.94) but the worst food safety indices for water and shrimp. The second farm also had a conventional system and used probiotics, but its area was 1.9 ha and with a stocking density of 56 shrimps/m2. It had the highest environmental load ratio (ELR = 28.17), but shrimp and water had better food safety indices than other farms. These two farms would have worse sustainability and food safety indices without the benefit of microorganisms. The third farm had 0.3 ha, a system with biofloc technology, and produced 400 shrimp/m2. It had the best renewability (R% = 14.79), environmental load ratio (ELR = 5.76), and emergy sustainability index (ESI = 0.20). Water and shrimp were within acceptable limits of microorganisms, and the type of biotechnology used contributed to different qualities of the final product. The microorganisms from biofloc technology and probiotics improve the sustainability and food safety indicators on aquaculture, but the absence of other sustainable practices limits these benefits.

Development of a framework for the sustainability evaluation of renewable and fossil fuel power plants using integrated LCA-emergy analysis: A case study in Iran

This study presents a comprehensive framework for evaluating renewable and non-renewable power plants' performance using the Life Cycle Analysis (LCA) and emergy analysis. The emergy analysis is used to consider the free ecosystem services in the sustainability of the systems as a supplement to the LCA. The results indicate that the wind and photovoltaic power plants have the best performance in terms of the LCA analysis, while the wind and combined cycle power plants have the highest emergy sustainability index. The best scenario is chosen under a two-objective optimization problem, including the single score and emergy sustainability as objective functions. Here, the wind power plant is the most interesting option while the combined cycle power plant with CO2 capture is the least interesting alternative. In this study, a novel framework is developed to assess the Cost of Avoided Carbon emissions (CACe) using the integrated LCA-emergy analysis for the combined cycle power plant in which its value is evaluated to be about $151.65/ton of CO2. Eventually, an uncertainty analysis is performed on the solar transformities using Monte Carlo simulation. The framework presented in this paper provides insights to increase power plants' sustainability for managers and authorities.

Sustainability of Regional Agroecological Economic System Based on Emergy Theory: A Case Study of Anhui Province, China

The agroecological economic system is the basic system on which human beings depend for survival. In order to better evaluate the operation status of a regional agroecological economic system and deepen the cognition of the input and output of the regional agroecological economic system from the angle of emergy, the evaluation method of sustainable development of the regional agroecological economic system with comprehensive consideration of resources, economy, and environment was proposed by constructing a unified dimensional measurement model. This paper analyzed and evaluated the data of the agroecological economic system in Anhui Province from 2010 to 2019. The results showed that the agroecological economic system in Anhui Province bore less environmental pressure and gradually decreased, and had a good system efficiency and economic benefits. The average emergy sustainability index (ESI) was 3.12, indicating that the agroecological economic system in Anhui Province had certain vitality of sustainable development. Based on this, the paper puts forward some suggestions on sustainable and high-quality agricultural development in Anhui Province, which provides theoretical and methodical support for sustainable development of a regional agricultural economy.

Emergy-Based Evaluation on the Systemic Sustainability of Rural Ecosystem under China Poverty Alleviation and Rural Revitalization: A Case of the Village in North China

A number of new rural management models have emerged to solve the problems of economic backwardness, insufficient resource utilization, and technical shortages in rural areas in the context of poverty alleviation to the rural revitalization strategy in China. However, the influence of new rural management model under all countermeasures for rural sustainable development with a comprehensive perspective is lacking. Therefore, exploring whether the new rural management model meets the requirements of sustainable development is an urgent issue. From the theory of system metabolism and emergy accounting method, this study classified the government funds for poverty alleviation measures as import resources, and analyzed the metabolic structure, efficiency, and the rural development factors of Chehe Village before and after poverty alleviation measures are carried out (the year of 2012 and 2019) to verify whether the new model was sustainable. According to the results of this study, the new management model of Chehe Village declined the rural system sustainability with the emergy sustainability index decreasing from 1.96 in 2012 to 0.32 in 2019. With the development of economy, the system metabolic efficiency of Chehe Village promoted and the metabolic structure became more reasonable manifesting in the decline of emergy use per unit GDP and the increase of emergy exchange rate. Moreover, production and livelihood had been highly valued in Chehe Village. In conclusion, it is feasible to add countermeasures of poverty alleviation and rural revitalization into the village system metabolism. The new management model of Chehe Village needs to change exogenous force into endogenous force to meet the requirements of rural sustainable development.

Sustainability assessment of agriculture production systems in Pakistan: A provincial-scale energy-based evaluation

Agriculture production in Pakistan is one of the main economic and social sector. It contributes about 20–25% to the country GDP and provides more than 60% employment opportunities for rural peoples, playing a backbone role in the country economy and food security. However, sustainable production of the agricultural system is very important to address a societal concern for environmental impacts and nutritional value, while maintaining an economically feasible production system for farmers. Therefore, this study used various indicators based on emergy accounting method to analyze the sustainability of the agriculture production systems in Pakistan from 2001 to 2015 in four provinces namely Punjab, Sindh, Khyber-Pakhtunkhwa and Baluchistan are investigated. The analysis indicates that (1) in all selected provinces the maximum portion among all inputs are purchase non-renewable inputs and purchase renewables input. Among in purchase non-renewable comprise inputs the largest portion are for labors, agriculture machinery and fertilizer inputs, while in purchase renewables comprise inputs the largest share are for water that used during irrigation purposes in all provinces. (2) In Punjab and Sindh, among purchase non-renewable comprise inputs the labor, pesticides and diesel were found decreased, while in Khyber-Pakhtunkhwa and Baluchistan the pesticides, diesel and electricity were found declined. The efficiency of overall output agriculture production in selected provinces are in the order of Punjab > Sindh > Kbyber-Pakhtunkhwa > Baluchistan. The output emergy share of the agriculture production increased by 66% in Punjab, 34% in Sindh, 110% in Khyber-Pakhtunkhwa and 72% in Baluchistan in the study period. (3) The analysis of overall agriculture performance through emergy based indicators indicates that the NRP% (non-renewable portion) ratio for Punjab declined by 12% while for Sindh, Khyber-Pakhtunkhwa and Baluchistan increased by 1%, 8% and 1%, respectively. That is why the EIR (emergy investment ratio) value is lower in Punjab and higher in other selected provinces. (4) The ESI (emergy sustainability index) values were declined for Punjab, Sindh, Khyber-Pakhtunkhwa and Baluchistan by 18.91%, 16.19%, 35.51% and 11.21% respectively, with average values of 0.51, 0.11, 0.22, and 0.21 indicates increased in Punjab than other provinces. We believe this study provides the policy makers and producers the understanding of the important drivers influencing agricultural system productivity and environmental, social and economic sustainability, and to create more adaptable and responsive management practices and strategies for truly sustainable agricultural production systems in Pakistan.

Researching on the Sustainability of Transportation Industry Based on a Coupled Emergy and System Dynamics Model: A Case Study of Qinghai

A series of environmental issues caused by excessive energy consumption in the transportation industry have hindered China’s sustainable development. In this study, an emergy synthesis method was used to analyze the flow of energy. Meanwhile, the emergy yield rate (EYR), environmental load rate (ELR) and emergy sustainability index (ESI) were calculated to evaluate the economic and environmental benefits of the system. In addition, we applied system dynamics to provide a scenario simulation method to compare the emergy indicators of the framework implemented. The paper further put forward some policy insights to improve the sustainability of the transportation system, including adjusting the transportation structure, increasing renewable energy use and promoting a circular economy. The scenario simulation framework based on the sustainable development model of emergy flow can provide a reference for the green development of transportation systems in other regions.

Toward the construction of a circular economy eco-city: An emergy-based sustainability evaluation of Rizhao city in China

The construction of the circular economy eco-city (CEE) is the most effective way to solve the problem of sustainable urban development. To promote its development, the evaluation and tracking of its sustainability have become significant in academic exploration. However, few efforts have been made in this regard. Thus, this paper aims to fill this gap by choosing Rizhao city, a coastal CEE, as a case study and employing an emergy-based method to assess its sustainability from 2005 to 2017. The study results show that the socio-economic development depends on the utilization of local non-renewable resources. Moreover, the self-support ratio was found to be above 94 %, which, in turn, led to an increase in the environmental loading ratio. However, due to a rise in resource recycle ratio, the emergy sustainability index and sustainable development index first showed a decreasing trend and then an increasing one. Consequently, the performance of the circular economy has improved, especially in terms of resolving the dilemma between a superior environment and a backward economy. Nevertheless, the coordinated development within the system was not adequate. Therefore, further policy recommendations have been made to improve the overall sustainability of the circular economy in Rizhao city.