Emergy Index Research Articles

Quantifying the environmental support to wild catch Alaskan sockeye salmon and farmed Norwegian Atlantic Salmon: An emergy approach

Understanding the relative contributions of the environment to commercial fisheries and aquaculture systems is an area of intense importance as it quantifies the dependence these human dominated systems have on healthy and productive ecosystems. Measures of sustainability are required that include environmental support, use of nonrenewable resources, and labor & services. This work draws on primary and secondary data used in an emergy analysis approach to assess environmental support and sustainability of a wild catch sockeye salmon fishery in Bristol Bay, Alaska and Atlantic salmon aquaculture in Norway. The analyses ended at the processing gate for both production systems. Environmental support of the sockeye fishery amounted to 69% of total inputs for landed fish and 37% for processed fish, while the environmental support for farm raised Atlantic salmon was 60% and 42% for landed and processed fish respectively. Labor and services contributed 53% of total inputs for processed sockeye and 44% for Atlantic salmon. The emergy indices for the wild caught sockeye and farmed Atlantic salmon systems were relatively high having emergy yield ratios for landed fish of 3.2 (wild caught sockeye) and 2.3 (farmed Atlantic salmon). After processing emergy yields of both systems were 1.6 (sockeye) and 1.7 (Atlantic salmon). Environmental loading ratios for the sockeye fishery were 0.45 and 1.69 for landed salmon and processed fish respectively, while for Atlantic salmon they were 0.76 and 1.40 for harvested and processed fish respectively. Emergy sustainability indexes (ESI) for both production systems were much higher than other aquaculture systems. Landed sockeye salmon had an ESI of 7.2, while that of farmed raised Atlantic salmon was 3.0, somewhat lower, but still a relatively sustainable source of high-quality protein.

The semi-intensive production model: A strategy based on emergy and economic analyses to realize sustainability in the ecosystem of Sistani beef cattle raising in Iran

Cattle rearing can benefit from the environmental support of native wetlands, through the establishment and proper management of units suitable for raising Sistani cattle ( Bos indicus ) around the Hamoun Wetland in the Sistan region of Iran. In this way, it is possible for cattle rearing to benefits from the environmental support of the wetland, thereby improving food security, fostering economic and social development, and contributing to the environmental protection of this sensitive region. In addition, helping to preserve the Sistani cattle breed, which is in danger of extinction, will be a significant benefit. This study was conducted from 2019 to 2020 on three different beef cattle production systems in the Sistan region. Both emergy and economic analyses were used to examine these production systems; 1) rearing the Sistani breed in an extensive production system, 2) rearing Sistani cattle in a semi-intensive production system, and 3) rearing an exotic breed within an intensive production system. In the extensive indigenous system, the amount of emergy supporting Sistani breed production was 2.30E+17 sej, which was less than the other two systems. Based on the economic output/input ratio (O/I EmV ), the yield of the Sistani breed in the semi-intensive system was 62% higher than that breed in an open system and 84% higher than exotic breeds in the intensive system. The values of the Emergy Exchange Ratio (EER), Transformity (Tr), and Specific Emergy (SpE) indices revealed that the Sistani breed outperformed the open system by 1.5 times and the exotic breed by 2 times in the intensive system. However, the sustainability of the Sistani breed raised under extensive and semi-intensive production systems is not guaranteed in the long run, given their dependence on production from the Hamoun wetland and the long-term meteorological data on declining rainfall, as well as, the decisions of Afghanistan, on the allocation of water rights to the upper watershed and to the downstream wetlands, which poses the risk of reducing the free environmental resources supplied to the Iranian wetland system. Due to these risk factors, designing the system for Sistani cattle raising as a semi-intensive production system is recommended as the way to most reliably attain the aforementioned benefits. • Emergy evaluation can be successful in selecting the right production model to improve the agroecosystems sustainability. • The structure and quantity of purchased inputs differed greatly across the systems studied. • Analyzing the economic and environmental condition of agro-ecosystems may assist evaluate their overall sustainability. • Emergy analysis is a comprehensive and explanatory method for assessing the sustainability of agro-ecosystems.

Knowledge structure of emergy theory in the field of eco‐compensation research: A grounded theory approach

AbstractAlthough emergy theory has made progress in the field of eco‐compensation research, there is still a lack of review articles, summarizing the existing knowledge structure in this area of study. Accordingly, the objective of this paper is to provide a reference for researchers by characterizing the current status of emergy theory in the field of eco‐compensation and to establish the internal logic structure among existing studies, based upon a qualitative analysis of textual data. Inspired by the grounded theory, twelve concepts within five categories of emergy theory were extracted by open, axial, and selective coding of relevant literature. Concepts were extracted from the texts and categories were determined according to the inherent logical relationships among those concepts. The “knowledge structure model of emergy theory in the field of eco‐compensation” was constructed and the following five principal categories were identified: “emergy indicators system,” the “integration of methods and theories,” “research subjects,” “calculation of compensation standards,” and “research concerns.” Moreover, core and supporting genera were also identified from these five axial codes. Finally, the research focuses and hotspots were explored according to the theoretical frameworks as indicated by the core and supporting genera. The findings of this paper provide a reference for researchers to further promote innovation in the application of emergy theory in the field of eco‐compensation.

Sustainability assessment of commercial Brazilian organic and conventional broiler production systems under an Emergy analysis perspective

This study aimed at assessing and comparing the sustainability of a Brazilian production unit representing the production of broilers reared in an organic system (UPrO) with a handling unit for the production of broilers reared in a conventional system (UPc) based on Emergy analysis. The analysis was carried following four steps: (i) definition, location, and data collection of broiler production units; (ii) Emergy diagram drawing; (iii) Emergy table construction; and (iv) result assessment according to the Emergy indicators in the graphical tools. According to the results, UPrO showed better environmental performance than UPc while UPc showed better productive efficiency. However, the Emergy Sustainability Index (ESI) results indicated that UPrO is sustainable in the short term, while UPc is unsustainable. Also, it is possible that the best environmental performance by UPrO is at the limit for systems specialized in the broiler production with a high-intensification degree. Since the corn and soybean meal were the inputs that most contributed to the total Emergy for both systems, and the yield comes from less concentrated sources of energy, the decision-making should be focused on to improve the environmental performance of the commercial broiler production systems being directed towards the reduction of the environmental load, from the use of ingredients with higher renewability(R%), i.e. organic corn and soybean feed usage.

Sustainability assessment of FLOCponics compared to stand-alone hydroponic and biofloc systems using emergy synthesis

FLOCponics is an intensive integrated agri-aquaculture system that combines biofloc-based aquaculture with hydroponics. Since research on FLOCponics is in its early stage of development, and many aspects of this system still need to be explored, the objective of this study was to assess and discuss the sustainability of a FLOCponics system and compare it to stand-alone biofloc and hydroponic cultures. This investigation will lead to a novel perspective of what troubling points need to be covered in the FLOCponics research field before they turn into a commercial scale problem. To do this, we conducted an experiment-based study by applying emergy synthesis to assess the sustainability of tilapia juveniles and lettuce production in FLOCponics, biofloc and/or hydroponic systems. The results indicate that the resources from the larger economy were the inputs that made the greatest contribution in all systems. Overall, most of the emergy indicators are similar for all systems, suggesting that FLOCponics, biofloc and hydroponic systems use low amounts of natural renewable resources, cause a moderate environmental load (EIR and ELR of 3.1 to 3.6), and lead to environmental stress seven times higher than the contribution to the economy (ESI of 0.3). Unit emergy values (UEVs) are different for each system, indicating that, under the evaluated conditions, FLOCponics (UEV: 2.54E + 06 sej/J) is more efficient than hydroponics (UEV: 5.55E + 10 sej/J) and less efficient than a biofloc system (UEV: 1.42E + 06 sej/J). Our findings provide valuable insights regarding the (un)sustainable aspects of FLOCponics and direct further research to improve the system's emergy performance. Based on the emergy performance, FLOCponics can be considered a promising sustainable food production approach, mainly considering that it is a system under development and there are still many opportunities for improvement.

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-to-aromatics 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.

Sustainability Assessment of Family Agricultural Properties: The Importance of Homeopathy

Family farming is a lifestyle and agricultural base that has ensured food for the world’s growing population in addition to the family’s own subsistence. However, the intensification of production processes to primarily generate exportable surpluses is based on the constant input of industrial inputs of low local socioeconomic viability. This study aims to evaluate the sustainability of family farms and their impact on the adoption of homeopathy instead of traditional/conventional intensification techniques. The study was conducted at six family farms located in the Serrana Mesoregion, Santa Catarina, Brazil, and include farms were classified according to the management and representativeness of their agricultural activity, i.e., conventional grains-cattle, milk-grains, grains and diversified, and according to their ecological basis, i.e., agroecological and organic. To discuss the sustainability of the family farms that were evaluated, the of metrics emergy synthesis, ecotoxicity potential and socioeconomic indicators are used. The results indicate that conventional diversified property has the best overall performance with regard to sustainability, including emergy yield ratio (EYR 1.88), emergy investment ratio (EIR 1.13), return on assets (1.22), hourly income of work (36.6 BRL/h) and income sufficiency (3.3). Agroecological and organic properties have better performance in renewability (76% and 75%), environmental load (ELR = 0.32 and 0.34), sustainability (ESI = 4.78 and 3.5) and potential ecotoxicity (1.736 and 1.579 kg 1.4 DCB-eq/ha). The contribution of homeopathy in an alternative scenario results in a 19% reduction in nonrenewable flows in conventional management properties and a decrease of up to 91% in ecotoxicity in grain + cattle properties. Using homeopathy, the return on assets and profit margin can be increased by up to 43% and income per hour of work and income sufficiency can be increased by 20% and 16%, respectively. This study contributes to discussions about the importance of using homeopathic therapies as a viable strategy that can be used in strategic public policy plans to improve the sustainability of family farms.

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.

Integrated emergy and economic evaluation of 8 hydropower plants in Zagunao Basin, Southwest of China

Hydropower has been regarded as a clean energy to replace fossil fuels facing the climate change, while detecting the tradeoffs among renewable energy production, greenhouse gas (GHG) mitigation and ecological impacts still remains challenge. Multi-disciplinary analysis should be adopted to understand these tradeoffs. This study proposed an integrated evaluation framework based on donor-side (emergy analysis) and user-side (economic analysis) which highlighted the impacts on ecosystem services. 8 hydropower plants in Zagunao Basin, Southwest China, were adopted as the study case. The results show that impacts on water supply and biodiversity dominated ecosystem service losses. Plants with higher water head are more efficient in resource utilization, while the efficiency of plants with gravity dams are generally lower than that with grille weirs under the similar installed capacity. Lixian plant had the best performance based on emergy indicators attributed by the benefits to utilize the renewable source from the regulating flow ability of Shiziping plant. Results from fair prices reflect that all the studied plants are not profitable under current grid price. Finally, policy implications were raised based on the results.

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.

Evaluation of regional sustainability through emergy analysis: a case study of nine cities in the Yellow River Basin of China.

The Yellow River is an important ecological shelter zone and economic belt in China. However, rapid urbanization and industrialization has produced a fragile ecological environment conditions and unbalanced economic development in the Yellow River Basin (YRB). Ecological protection and high-quality development of the YRB has been China's national strategy since 2019. As the only coastal province with the largest economy and population in the YRB, the sustainable development of Shandong Province is of great importance in the region. This study evaluated the dynamic trend of sustainability levels of the nine cities in Shandong Province in the YRB through emergy analysis. Emergy-based indicators were established and analyzed from 2010 to 2019, taking account of the ecological service emergy (ESE) needed to dilute pollutants and emergy equivalent loss (EEL) on ecosystem quality and human health damage. Results showed that emergy sustainable indicators (ESI) in Tai'an, Heze, Dezhou, and Liaocheng ranged from 1 to 10, which had the potential for sustainable development. The ESI value of Jinan, Jining, Zibo, Dongying, and Binzhou was less than 1, which indicated that these cities were under great ecological pressure. The value of emergy indicators for sustainable development (EISD) of the nine cities all declined from 2010 to 2016, but remained stable from 2017 to 2019. Based on findings from the emergy analysis regarding policy implications and local conditions, the study concludes by providing proposals to improve regional sustainability.

Sustainability Evaluation of Immobilized Acid-Adapted Microalgal Technology in Acid Mine Drainage Remediation following Emergy and Carbon Footprint Analysis.

Sustainability evaluation of wastewater treatment helps to reduce greenhouse gas emissions, as it emphasizes the development of green technologies and optimum resource use rather than the end-of-pipe treatment. The conventional approaches for treating acid mine drainages (AMDs) are efficient; however, they need enormous amounts of energy, making them less sustainable and causing greater environmental concern. We recently demonstrated the potential of immobilized acid-adapted microalgal technology for AMD remediation. Here, this novel approach has been evaluated following emergy and carbon footprint analysis for its sustainability in AMD treatment. Our results showed that imported energy inputs contributed significantly (>90%) to the overall emergy and were much lower than in passive and active treatment systems. The microalgal treatment required 2–15 times more renewable inputs than the other two treatment systems. Additionally, the emergy indices indicated higher environmental loading ratio and lower per cent renewability, suggesting the need for adequate renewable inputs in the immobilized microalgal system. The emergy yield ratio for biodiesel production from the microalgal biomass after AMD treatment was >1.0, which indicates a better emergy return on total emergy spent. Based on greenhouse gas emissions, carbon footprint analysis (CFA), was performed using default emission factors, in accordance with the IPCC standards and the National Greenhouse Energy Reporting (NGER) program of Australia. Interestingly, CFA of acid-adapted microalgal technology revealed significant greenhouse gas emissions due to usage of various construction materials as per IPCC, while SCOPE 2 emissions from purchased electricity were evident as per NGER. Our findings indicate that the immobilized microalgal technology is highly sustainable in AMD treatment, and its potential could be realized further by including solar energy into the overall treatment system.

Emergy-based environmental accounting of graphite anode material production

Natural graphite is often regarded as a critical mineral because it is currently the most widely used battery anode material (BAM) for commercial lithium-ion batteries. However, studies on evaluating the criticality of natural graphite are still lacking, especially how to evaluate its substitutability from an environmental perspective. Emergy is defined as the sum of all the solar energy required to generate a product or service and emergy synthesis is one effective method for environmental accounting. This study employs an emergy synthesis method to compare the efficiency and sustainability of BAM production processes with different raw material inputs - natural graphite and its major substitute synthetic graphite. The overall environmental performance of graphite BAM production is also examined by evaluating the contribution of natural capital and ecosystem services. Results show that the total emergy input for natural graphite BAM production was 4.72E+10 sej/g, dominated by natural graphite deposit, while the total emergy input for synthetic graphite BAM production was 2.34E+10 sej/g, dominated by petroleum coke and electricity. Based on the emergy indicators, the BAM production from synthetic graphite is considered as a preferable option because such production process will lead to better economic and environmental performances and improve the overall resource efficiency. These results also imply that the criticality of natural graphite might be overestimated since the substitution of synthetic graphite in BAM manufacturing is economically and environmentally feasible.

Emergy Evaluation of Methanol and Naphtha to Aromatics Systems Combined with Renewable Power Generation

Methanol to aromatics is proved to have better performance than traditional naphtha to aromatics in terms of aromatics demand increasing and the petroleum resources decreasing. The electricity source has a great impact on the performance of aromatics production systems according to the emergy evaluation. Basing on the emergy evaluation of different aromatics production systems and renewable power generation systems, the emergy indices of aromatics production systems are discussed when the electricity is generated from renewable resources. The sustainability levels of the systems are analysed when the emergy proportion of electricity is uncertain. The results show that all the methanol to aromatics systems will be sustainable when the hydropower is applied. When the biomass direct-fired power is used, the natural gas and coke oven gas-based systems show weak sustainability while the coal-based system will be unsustainable. For the situation that the electricity has uncertain emergy proportion, the coal, natural gas and coke oven gas-based systems will become sustainable when the renewable proportion of electricity is greater than 0.40, 0.20 and 0.20.

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.

Environmental Assessment of Healthcare Facilities in the Global South -- A Case Study from Pakistan

Pakistan is a resource-constrained country, poor in municipal and healthcare facilities. Existing healthcare structures in the country are often over-crowded, and an effective monitoring and assessment of their sustainability is therefore crucial. In this study, a systemic approach is outlined to evaluate the environmental sustainability of the largest and sole public hospital in the major city of Gujranwala, in the Punjab region of Pakistan. The Emergy (spelled with ``m'') Accounting (EMA) method is applied. Its operationalization allows to keep track of the amount of energy that was consumed in direct and indirect transformations to make a product or service. Relevant data include the hospital requirements in terms of energy, water, products, labor, and services. The EMA results offer a supply-side geobiosphere-oriented perspective. Emergy indicators show that the hospital is indirectly responsible for a significant stress on the environment, that might be decreased by an increased efficiency in the resource use. On the other hand, a hospital is a complex system, depending on skilled laborforce as well as on several fine imported medical products and related services, making it dependent on external socio-economic systems. The presented results address the geography dependent characteristics of the hospital, and can be used for benchmarking and future evaluation of similar hospitals within and across the region.

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.

Assessing the sustainability of tilapia farming in biofloc-based culture using emergy synthesis

Biofloc technology (BFT) has been called an environmentally friendly aquaculture approach. The sustainable characteristics of biofloc-based culture are usually linked to the efficient use of water and nutrients and the minimal discard of effluent to the environment. Given the scarcity of sustainability assessment of biofloc-based systems, it is still unclear whether the positive characteristics of BFT make it a real sustainable approach for aquaculture. This study aimed to investigate and apply the emergy synthesis to assess the sustainability of commercial Nile tilapia fingerlings production in a biofloc-based system. The tilapia fingerlings produced on the BFT farm showed a UEV of 2.04E + 03 sej/J, renewability of 32.73%, EYR of 1.00, EIR, and ELR of 2.05, and ESI of 0.49. Compared to other aquaculture systems, the evaluated BFT farm presented emergy indicators with values characteristic of potentially sustainable production. Electricity has the highest representativeness in the emergy input, making the system dependent on resources from the larger economy. The low UEV indicates that the BFT farm is efficient in terms of converting the invested emergy into the system’s output (tilapia fingerlings). A sensitivity analysis shows that replacing the hydroelectric source of electricity with photovoltaic will not improve the emergy performance of the evaluated BFT farm.

Evaluating the sustainability of rural complex ecosystems during the development of traditional farming villages into tourism destinations: A diachronic emergy approach

Many villages that have transformed from traditional agricultural communities into tourism destinations to eliminate poverty are encountering ecological and social crises that threaten sustainable development. The dilemmas of rural complex ecosystems are the cumulative results of historical material and energy exchange between humans and nature in the social-ecological dimension. A tool for evaluating sustainability, emergy theory, measures different resource flow qualities. To conserve healthy rural ecosystems, dynamic equilibrium with a coupled interrelation of social development and energy operation must be maintained within system carrying capacities. This raises the question that current emergy studies ignored of how to explore reference indicators for technical solutions and the roots of sustainability change for rural governance systems under social development. This paper proposes a diachronic emergy approach that integrates emergy evaluation into an environmental history research framework with social development models and social-ecological factors to realize system well-being. Considering the village of Hekeng, China, emergy accounting was performed for three typical years (1953, 1990 and 2015) combined with social development models (traditional agriculture, chemical-assisted agriculture and commercial tourism periods). Based on the benchmark year 1953, a diachronic analysis of changes in emergy indicators reconstructed in a social-ecological context and corresponding social-ecological factors was conducted. The results show that the EYR and ELR of 3.16 and 0.53, respectively, for 1953 can be employed as reference indicators of resource utilization in the sustainable development of Hekeng. The potential impacts of resource use changes on the system's well-being were explored, and the findings indicate that technical solutions must be integrated with a governance system based on production relations, forest environments and community culture. Recommendations for sustainable development of ecological agricultural techniques, ecotourism modes, and governance with social-ecological integration are proposed. The diachronic emergy approach provides a new perspective for the implementation of technical solutions in human society and the formation of sustainability strategies for system well-being.

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.