Environmental Loading Rate Research Articles

Data-driven sustainability evaluation and manufacturing system enhancement from economic, environmental, social, and sustainability perspectives.

Sustainable manufacturing is crucial to achieving carbon neutrality targets. However, research on the sustainability of manufacturing systems is limited, and high consumption, low efficiency, and high emissions have resulted in high resource consumption and rapid environmental degradation. Therefore, it is of great importance to establish an evaluation and improvement indicator system conducive to sustainable development. To this end, this study developed a data-driven methodology for evaluating and enhancing the sustainability of manufacturing systems. Manufacturing system production process data, with data dimensions unified via the emergy method, were used to construct a sustainable development evaluation model that includes four perspectives: economy, environment, society, and sustainability. The model was applied to a flange production workshop in China to analyze the interrelation mechanisms among energy consumption, resource consumption, and environmental pollution, and identify optimization schemes to improve sustainability. After implementing these optimization schemes, the emergy yield rate (EYR) of the flange increased by 23.40%, the environmental load rate (ELR) decreased by 19.03%, the per capita emergy (EPP) increased by 6.88%, and the emergy-based sustainability index (ESI) increased by 52.76%. The method presented herein offers a novel and effective tool to analyze and visualize sustainable development in manufacturing systems and identify the relationship between technology and management in the manufacturing industry; however, this method is based on historical data and rules, and lacks of flexible response to unknown situations. The results provide a reference for enterprises to achieve sustainable and lean manufacturing.

An approach for measuring and analyzing embodied carbon in the construction industry chain based on emergy accounting

This study proposes a comprehensive approach to analyze the embodied carbon in China’s construction industry by integrating carbon emission factors and an input–output model. The analysis covers the whole construction industry chain, including both direct and indirect carbon emissions. Moreover, this study introduces an emergy index system that incorporates the ternary diagram of materials science for environmental assessments, assessing resource allocation, development effectiveness, efficiency, and sustainability. The research measures the embodied carbon emissions for seven regions in China’s construction industry, and compares the results from the perspective of the whole industry chain. The study reveals that indirect carbon emissions contribute significantly to the embodied carbon emissions in China’s construction industry, and the central region exhibits the highest environmental loading rate among all regions. Additionally, the northern region shows the highest emergy yield rate, whereas the eastern and northeastern regions exhibit better sustainability in the development of the construction industry.

Study on biochar and silicon co-production technology of rice husk based on the new ammonia CO2 capture method and its comprehensive benefits

Biomass energy coupling with CO2 capture-utilization-storage (BECCUS) technology has been confirmed essential for achieving net-zero CO2 emissions. A new co-generation technology for producing porous biochar and nano silica from rice husk, with KOH and K2CO3 as silica solubilizers, based on the new ammonia-based CO2 capture method is innovatively proposed, whose energy value-economic analysis model is established, and its comprehensive benefits are further investigated. The results of the energy value analysis show that the BECCU technology is environmentally friendly, especially when the reaction reagent is K2CO3, the environmental loading rate is reduced from 1.19 to 0.19, and the sustainability index is increased from 1.40 to 5.32. The economic evaluation results show that it leads to a higher Net Present Value (NPV) and Internal Rate Return (IRR) of the system with solid profitability and self-solvency. While when KOH is selected as the reaction reagent, the NPV increases from 34,253,700 RMB to 119,637,600 RMB, the IRR increases from 40.84% to 59.70%, and its profitability and self-solvency reach the optimum. It provides new ideas for the utilization of biomass energy in low-carbon and multi-production, accompanied by the large-scale consumption and informed utilization of ammonia-based CO2 capture products.

Integrated life cycle assessment and emergy analysis of liquid dehumidification absorption refrigeration driven by solar energy

The cascade utilization of solar energy is significant in alleviating energy and environmental problems. A novel solar-driven liquid dehumidification cascade absorption refrigeration (SLDAR) system applied to hot summer and cold winter areas of China is proposed in this paper. In order to evaluate the environmental and economic sustainability of the system, an integrating life cycle assessment and emergy analysis (LCA-EmA) method is developed. Parameter sensitivity analysis is conducted to determine the effects of solar radiation intensity, air temperature and relative humidity on the sustainability of the system. The results reveal that the total potential environmental impact of the system is 7.29E+03, of which the construction stage accounted for the most part of 65.36%. The total emergy input of the system is 1.61E+17 sej/yr, the operation stage accounted for the highest proportion of 73.29%. According to the integrated LCA-EmA, the emergy sustainability index of the system is 3.89, which reduces by 29.01% than the result of the emergy analysis. The parameter sensitivity analysis states that the system has higher resource use efficiency and emergy yield ratio in higher solar radiation intensity. And the emergy sustainability index of the system increases first and then decreases as the air temperature increases. The environmental load rate increases by 15.19% and the emergy sustainability index decreases by 44.50% as the increase of relative humidity. This study proves the feasibility and sustainability of the solar-driven cascade system.

Assessment and Suggestions on Sustainable Development of Regional Ecological Economy Based on Emergy Theory: A Case Study of Henan Province

A rapid development in regional economy is often accompanied by an increase in energy consumption and the intensification of environmental pollution, which brings great pressure to the social economy and the natural environment. In order to solve the integrated problem of economic, social, and natural factors, we propose an evaluation method for the sustainable development of the regional economy, based on emergy. By analyzing the statistical data of Henan’s economic development from 2010 to 2018, an evaluation index system of regional eco-economic sustainable development was constructed based on four aspects: natural subsystem, economic subsystem, social subsystem, and sustainable development index. The index system was then used to measure and comprehensively evaluate the sustainable development of the ecological economy and the environmental friendliness of Henan Province. The assessment results showed that the emergy self-sufficiency rate decreased, indicating decreased self-sufficiency. Moreover, the environmental load rate was high, indicating high environmental pressure. The emergy currency rate declined with a rise in the emergy investment rate, indicating economic growth. Additionally, the population carrying capacity was consistently > 1, indicating that the population was overloaded. Collectively, the emergy-based evaluation method of regional economic sustainable development in this study provides a comprehensive and scientific evaluation framework, which can help decision makers and researchers better understand and evaluate the problems brought about by the rapid development of regional economy, and provide targeted decision making suggestions. It includes four sub-systems: natural, economic, social, and sustainable, which have important theoretical and practical significances, while also serving as a useful reference for the evaluation of the sustainable economic development of similar regions.

Bi-Objective Optimization and Emergy Analysis of Multi-Distributed Energy System Considering Shared Energy Storage

Shared energy storage (SES) provides a solution for breaking the poor techno-economic performance of independent energy storage used in renewable energy networks. This paper proposes a multi-distributed energy system (MDES) driven by several heterogeneous energy sources considering SES, where bi-objective optimization and emergy analysis methods are used for the system’s optimal capacity planning and operating scheduling considering economic, environmental, and sustainable performances, and Nash bargaining is adopted for the reasonable distribution of benefits of MDES. Then, an energy system composed of four different DESs (distributed energy system) considering one Shared Energy Storage Operator (SESO) is taken as an example for further study, namely one to four shared energy storage multi-energy systems, where MDES with and without SESO are compared. The results reveal that the operation cost of MDES considering SESO and Nash bargaining is reduced by 3.03%, while all the distributed energy systems have lower operating costs, and SESO has an additional income of $142.4/day. Correspondingly, the emergy yield ratio, emergy sustainability index, and emergy investment ratio of the corresponding system increase by 5.15%, 3.83%, and 9.94%, respectively, wherein the environmental load rate increases by 1.67% because of the greater consumption reduction of renewable resources than that of non-renewable resources under the premise of reduced emergy consumption.

Evaluating Agricultural Sustainability and Green GDP in China: An Emergy Analysis

Agricultural sustainability is the foundation and a guarantee of sustainable human reproduction. The scientific assessment of China's agricultural sustainability is a prerequisite for properly resolving the conflict between short-term economic interests and long-term ecological security. This paper uses the emergy analysis method to estimate agricultural sustainability in China and further calculates the agricultural environmental cost and green GDP. The results show that China's agricultural emergy yield rate (EYR) is generally greater than 1. This means that more emergy is obtained in relation to renewable and non-renewable inputs from human activity, which also indicates that China's agricultural agroecosystem is characteristic of a profound transition from a self-supporting tradition to a modern industry based on external economic resource consumption. In contrast, China's agricultural growth is mainly driven by the input of a large amount of non-renewable resources, which makes the environmental loading rate (ELR) increase year by year, resulting in the deterioration of China's agricultural emergy sustainability index (ESI). China's agricultural green GDP accounts for about 94.4% of traditional GDP, which means that the average agricultural environmental cost is about 5.6%, mainly from land loss, accounting for 48.23% of the environmental cost.

A Scenario Simulation Method for Regional Sustainability Coupled with SD and Emergy: Implications for Liaoning Province, China

The eco-economic system is a complex system based on human activities, and the sustainability of the eco-economic system needs to maintain the balance between the three subsystems of society, economy, and environment. In this work, a comprehensive evaluation index system of the ecological-economic system of Liaoning Province in China was constructed by combining the emergy analysis and the system dynamic (SD) model, and four development scenarios were designed by adjusting the influencing factors of the ecological-economic system, based on the simulation and evaluation of the sustainable ecological and economic development of Liaoning Province from 2017 through to the next 19 years. The conclusion shows that, under the scenario of coordinated development type, the GDP, emergy density, and emergy output rate of Liaoning Province show an increasing trend; the ecological load, such as waste emergy ratio and environmental load rate, is small; and the sustainable development index and emergy sustainable development index are at a high level compared to other programs.

Performance comparison of sewage treatment plants before and after their upgradation using emergy evaluation combined with economic analysis: A case from Southwest China

Upgradation of sewage treatment plants has been greatly promoted in China, but few studies investigate impact of this practice on synergetic relationship between environmental performance and economic performance of those systems. This study aims to investigate environmental sustainability, economic benefit and greenhouse gasses emission intensity of different sewage treatment schemes and then identify the best one as well as related negative factors needed to be addressed in the future. A comprehensive performance index-Synergetic effect index (SEI), derived from integration of Improved emergy sustainability index (IESI), Net economic benefit ratio (NEBR) and Carbon emission per unit sewage treatment (CEUS), is proposed to address this issue. Firstly, to investigate environmental sustainability of sewage treatment more completely, this approach improved the classic emergy analysis through integrating emissions’ impacts into related classic emergy yield ratio and environmental loading ratio respectively and then built the comprehensive index IESI. Next the indicator NEBR and CEUS were proposed to assess economic benefit and greenhouse gasses emission intensity, respectively. Finally, the three indicators, i.e. IESI and NEBR as well as CEUS, are merged into the index SEI to evaluate comprehensive performance of sewage treatment. A sewage treatment plant, located in Southwest China, as a research case, was investigated using the presented approach from its construction stage to its operation stage. It is found that, after the upgradation, total emergy input increases by 11.96% mainly from extra thermal electricity power consumption, total emission's’ impact decreases by 39.92% mainly from raised removal rate of total phosphorus, emergy yield rate is slightly improved and environmental load rate descends greatly, and thus the sustainability level clearly rises. Meanwhile, environmental emissions significantly affect the environmental load and then the sustainable level. This upgradation improves its economic benefit because rising sewage treatment fee slightly exceeds its added treatment cost. Thermal electricity power consumption in operation stage is the main contributor to total carbon emission. Sensitivity analyses shows that changes of main input categories have not altered the research results. Generally, the upgradation promotes the synergetic relationship between its environmental performance and economic performance by 95.65%. However, indirect environmental emissions from the upgradation should be emphasized. This enterprise should further improve energy performance, optimize the existing processes and promote its circular economy in the future.

Sustainability Analysis of a Municipal Wastewater Treatment Plant through Emergy Evaluation

Water and wastewater treatment plants are essential for the supply of drinking water for consumption and the treatment of effluents produced by human/industrial activities. However, few studies deal with the investments and sustainability of these services, which consider both the contribution of nature and society. This study uses the emergy approach to evaluate a wastewater treatment plant located in the northeastern part of Romania, in Iași city. An assessment of the environmental costs of natural fluxes required for the treatment processes was performed, considering that the treated effluent is, still, loaded with contaminants that have to be absorbed by the receiving water natural system. The work done by nature to assimilate this load, generally considered free, is esteemed as a further cost in the total emergy budget of the wastewater treatment processes. The sustainability perspective was approached by calculating and analyzing the emergy yield ratio (EYR), environmental load rate (ELR), and emergy sustainability development index (ESI). The use of local renewable natural resources in Iași municipal wastewater treatment plants is negligible (1.71% of the total plant emergy budget), as compared to that of the purchased resources (98.29% of the total plant emergy budget) mainly processed with the support of fossil fuels’ generated energy. The unit emegy value was, also, calculated and compared to other studies relevant for wastewater treatment plants. The analysis suggests that the large amount of emergy that wastewater contains is proportional to the number of resources employed for wastewater treatment and the extensive effects on surrounding ecosystems, where wastewater is discharged.

Eco-Efficiency Assessment of Beijing-Tianjin-Hebei Urban Agglomeration Based on Emergy Analysis and Two-Layer System Dynamics

In the process of the economic development of the Beijing-Tianjin-Hebei urban agglomeration, ecological and environmental issues are still an important factor restricting high-quality development. The study of eco-efficiency is of great significance for coordinating the relationship between economy, resources and environment. This paper used a combinated method of two-layer system dynamics and emergy analysis to construct an emergy–system dynamics coupling model for eco-efficiency evaluation from the subsystems of resource flow, energy flow, currency flow and population flow of urban system, which is used to simulate and analyze the eco-efficiency of the Beijing-Tianjin-Hebei urban agglomeration. The results show that the overall eco-efficiency of the Beijing-Tianjin-Hebei urban agglomeration is not high, with an average value of 0.3786, and there is a trend of the value rising first and then falling from 2000 to 2035. The index values of emergy waste rate, contaminant emergy ratio, emergy output rate and environmental load rate after the decomposition of the eco-efficiency show that the high environmental pressure, the low re-use rate of pollutants and the low production efficiency of the system are important reasons for the low eco-efficiency in regional economic development. Finally, through scenario simulation, we propose that optimizing the economic structure, adjusting the population size and rationally arranging the fixed assets investment are conducive to improving the eco-efficiency of the Beijing-Tianjin-Hebei urban agglomeration.

Carbon footprint analysis of straw collection, transportation, and storage system for power generation in China based on emergy evaluation.

Carbon footprint analysis method was employed to evaluate the ecological benefits of the straw collection, transportation, and storage system based on the case of Laifa Straw Recycling Company, and the emergy-based carbon emission indicator system was also set up to assess the relationship between input resource and carbon emission. In the condition of collecting 2 × 108 kg of straw production, the carbon emission of the artificial model (7.26 × 103 t CO2eq) and mechanical model (6.11 × 103 t CO2eq) was greatly lower than that of the straw burned in the field (2.78 × 105 t CO2eq). According to the emergy-based carbon emission indicator system, the carbon emission of straw recycling system was mainly triggered from labor input, which could be reduced by adjusting the resource structure. The ratio of carbon emission to environmental loading rate (ELRCO2) and ratio of carbon emission to emergy sustainability index (ESICO2) of the artificial model were 90.75E+6 kgCO2eq and 1.52E+6 kgCO2eq, respectively, which were higher than that of the mechanical model, 55.55E+6 kgCO2eq and 1.22E+6 kgCO2eq. It was obviously that the mechanical model had weaker influence on environmental loading than that of the artificial model and presented promising sustainable development ability in the case of mitigating carbon emissions.

Comprehensive evaluation of environmental and economic benefits of industrial symbiosis in industrial parks

The benefit evaluation of industrial symbiosis in industrial parks plays an important part in park management. This study aims to propose a comprehensive assessment method for industrial symbiosis benefits by combining resource productivity and considering the impact of emissions in emergy analysis. Besides, classify industrial symbiosis according to the exchange of materials, water, and energy to conduct an in-depth analysis of diverse symbiosis. The case study of an eco-industrial park in China shows that industrial symbiosis has a positive effect in many aspects, including increasing the productivity of direct input materials, water, and energy by 0.33, 36.50, and 0.38 times respectively, reducing the emission impact by 30.91%, saving economic investment equal to 30.18% of gross domestic product, reducing the environmental load rate by 23.88% and increasing the sustainable development index by 32.74%. Suggestions on building a symbiosis network are put forward by comparing the contributions of symbiosis types. This study provides park managers with a symbiosis classification and a benefit evaluation tool to build symbiosis networks and make policies for sustainable industrial development.

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.

Study on the Choice of Wastewater Treatment Process Based on the Emergy Theory

With the increase in industrialization and urbanization, water pollution has become increasingly serious, and wastewater treatment has become a common step in preventing this. For a greater understanding of the sustainability of different wastewater treatment systems, two processes, Anaerobic Baffled Reactor + Anaerobic-Anoxic-Oxic and Anaerobic Baffled Reactor + Cyclic Activated Sludge System, were selected, and their sustainability was evaluated based on three indicators, namely emergy yield ratio, environmental load rate, and emergy sustainability development index, according to emergy theory. The results show that the emergy yield ratio and environmental load rate of the ABR + CASS process were lower than those of the ABR + A2/O process, and the emergy sustainability development index of the ABR + CASS process was higher than that of the ABR + A2/O process, showing better sustainability. The research methods and findings of this study play an important role for decision makers in selecting sustainable wastewater treatment processes.

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.

Evaluation and improvement path of ecosystem health for resource-based city: A case study in China

Chinese resource-based cities are facing serious challenges in the aspect of ecosystem health development due to the development mode of “Treatment after pollution” and the negative effect caused by increased global competition. Research from the theory and methodology aspects must be urgently advanced. This study innovatively combines emergy analysis indicators with traditional economic-social indicators and constructs the method for urban ecosystem health assessment and improvement path. Jining is selected as an example to verify the method effectively. Research results show that the urban ecosystem health level of Jining constantly improved during 2008–2017, which increased from unhealthy to sub healthy and then to healthy. The five urban ecosystem health factors, namely, vitality, organizational structure, resilience, ecosystem service functions, and public health conditions, all show a trend of continuous improvement. Through the model of obstacle degree, this study identifies the main obstacle factors that influence the urban ecosystem health development of Jining: environmental loading rate (D22), renewable emergy value rate (D7), and the proportion of environmental protection in fiscal expenditure (D19). Moreover, several ecological development paths are proposed to improve the urban ecosystem health level of Jining based on local conditions.

Emergy-based environmental impact evaluation and modeling of selective laser melting

Additive manufacturing (AM) technologies, such as direct laser and selective laser melting (SLM) manufacturing, allow the fabrication of functional products with high added value. This paper proposes an emergy-based method for evaluating the environmental impact and economic cost of the SLM manufacturing process while considering the environmental flows (materials, energy, and wastes) and economic factors (time, costs, and quality). By analyzing the emergy flows in an SLM system, sustainable evaluation indexes are developed to estimate its sustainability level. Then, the method is applied to analyze the environmental impact and economic cost of the SLM of a part. The results show that the cost of the process for a single part is high, the net emergy yield ratio of the SLM system is low, and its environmental load rate is very high. The sustainability indexes of the system indicated a high environmental impact and low production efficiency. However, the waste emergy output ratio of the system was very low, which reflected the near-net-shape characteristics of SLM, indicating a high sustainability potential. The results of this study are expected to contribute to increased sustainability and optimization of SLM.

Plastic pollution load Model based on Stepwise regression Analytic hierarchy process

This paper focuses on plastic pollution, which is the key problem in national environmental problems. With the increasing influence of plastic pollution, in order to measure the impact of plastic pollution, reasonable intervention measures are put forward, and environmental load rate model is established. In this paper, the stepwise regression method is used to estimate the maximum pollution level that can be achieved in the world from the aspects of population density, vegetation cover, industrial level and economic level, so as to provide reference for global pollution control.

Biogas potential and methanogenic community shift in in-situ anaerobic sewage sludge digestion with food waste leachate additions

The objective of this study was to determine methane yields (MY) of organic wastes in biogasification facilities according to the mixing ratio of food waste/food waste leachate and sewage sludge. One biogasification facility that treated sewage sludge only was compared with three biogasification facilities treating sewage sludge and food waste. The theoretical MY was derived based on analyses of carbohydrate, fat, and protein to examine the efficiency of the biogasification facility. The average actual MY was 0.424 Sm3CH4/kg volatile solids, which corresponded to 83.7% of theoretical MY. In the case of combined anaerobic digestion (CD) mixing with food waste/food waste leachate, inhibitory factors (volatile fatty acids [VFAs], total nitrogen [TN], and organic matter contents) showed the tendency to have relatively higher values in CD facilities than in the biogasification facility treating sewage sludge only. Mean concentrations of VFAs and TN in the anaerobic digester effluent, and the organic loading rate were 406 mg/L, 3,721 mg/L, and 1.62 kg volatile solids/m3 day, respectively. The influence of anaerobic digester effluent was in charge of 10% within the influent environmental loading rate from the sewage treatment plants associated with the biogasification facilities. Analyses of the microbial community showed that a remarkable change in the structure of methanogens was directly related to different MY in each plant. In particular, Methanoculleus and Methanosaeta increased with an increasing ratio of food waste/food waste leachate to sludge, while Methanococcus and Methanosarcina decreased. In conclusion, CD showed steady operational conditions and high efficiency of MY by injecting food waste/food waste leachate into the anaerobic digester. It met the current criteria for integrated treatment of organic waste in biogasification facilities in South Korea.