Emergy Perspective Research Articles

Rethinking the China-U.S. Trade balance from 2001–2020 based on emergy perspective

In the year 2018, escalating trade imbalances between China and the United States led to a trade war over tariffs and trade policies that garnered global attention. While trade deficits are primarily reflected in currency terms, trade involves a broader exchange of different resources. Hence, this study employs Emergy Accounting approach (EMA), an environmental quality-oriented assessment method, to collect official statistical data from both countries and consider differences in statistical data weight. Utilizing the NEAD V2.0 database, this research calculates and discusses the total emergy flow, trade imbalances, and structures in China-U.S. trade from 2001 to 2020. Additionally, it computes and analyzes emergy indicators, delving into the dynamic changes in the emergy values of various categories of goods. The results indicate a gradual balance in the emergy trade deficit between China and the United States, with both countries benefiting from the trade. Specifically, China benefits from importing raw materials from the United States, while the U.S. gains from importing inexpensive embodied labor from China. Considering differences in data statistical calibers and applying the EMA contribute to a more accurate understanding of the trade situation and the correction or prevention of errors. The Emergy theory provides a new perspective for a comprehensive assessment of trade relationships. China and the United States have the potential to establish a fairer, more balanced, collaborative, and sustainable trade relationship, contributing to global sustainable development.

Unlocking the potential of municipal solid waste: Emergy accounting applied in a novel biorefinery

The rampant municipal solid waste (MSW) generation caused mainly by people's lifestyle has required technological solutions to deal with this global issue. This paper assess an innovative and integrated biorefinery (2IB) to manage MSW. The 2IB is rooted in the circular economy concept, and it differs from any other currently existing technological route in managing MSW due to its integrated processes that receives both inorganic and organic fractions at the same time, besides unveiling an innovative aspect related to thermoplastic production. Due to its scientific-based advantages, the emergy accounting (withy ‘m’) is considered as method to quantify the 2IB environmental performance, comparing the results with alternatives MSW management facilities. Results show that 2IB has similar performance for the three traditional emergy indicators (m-EYR of 1.17, m-ELR of 5.73 and m-ESI of 0.20) compared to incineration and landfilling, indicating low yield, moderate load on the environment, and unsustainable. On the other hand, the emergy return indicator (ERI of 20.33) indicates higher performance for the 2IB, in which for each solar emjoule (sej) – the measure unit of emergy – invested it generates a return of about 20 sej that becomes available as benefits for societal development. From an emergy perspective, results support that 2IB should be considered as a powerful technological alternative to manage MSW. This study contributes from a theoretical perspective with discussions on the emergy accounting procedures applied on systems located at far right side of energy hierarchy, while contributing from a practical perspective by providing technical information about the 2IB that supports decision makers towards more sustainable MSW management systems.

Can additional agricultural resource inputs improve maize yield, resource use efficiencies and emergy based system efficiency under ridge-furrow with plastic film mulching?

Water scarcity is a major constraint for maize production in drylands. As an efficient water-saving technology, the ridge-furrow with plastic film mulching (RM) system has achieved success in dryland farming. The efficiency of the rainwater-harvesting system in RM is greatly affected by erratic precipitation, and water absorption by crops is influenced by nutritional availability. Whether the additional supply of irrigation and nitrogen (N) resources under the RM system could influence the resource use efficiencies, emergy flows, and system efficiency of agricultural products is unclear. Therefore, a 3-year field study on maize plants consisting of four planting patterns (CP: conventional planting; RM; RM + SI: RM plus supplementary irrigation; RM + SI + N: RM + SI plus additional N fertilizer) was conducted from 2018 to 2020 in the Loess Plateau of China to determine resource use efficiencies, emergy flows, and system efficiency through emergy evaluation. In this study, we demonstrated the high efficiency of the micro-field rainwater-harvesting system of RM by collecting more rainwater and improving soil hydrothermal conditions. For example, the soil temperature and moisture of topsoil at seedling stage were increased by 4.3 °C and 13%, respectively, under RM compared with CP. The soil hydrothermal conditions in RM further improved maize yield (+35%), water use efficiency (+32%), N partial factor productivity (+37%), radiation use efficiency (+10%), and system efficiency (8%, from an emergy perspective), compared to CP. However, the additional supply of N or irrigation in RM + SI or RM + SI + N planting patterns failed to increase resource use efficiency, although the maize yield was increased by 9%. Furthermore, although the total emergy input was increased by 19%, it did not significantly increase energy output, and thus decreased the resource efficiency by 9% through emergy evaluation, compared to RM. Overall, RM without additional agricultural resource input could be recommended as a sustainable and cleaner production strategy for maize in drylands to address the issues of ever-increasing food demand and declining availability of production resources.

Valuation of losses and damages resulting from the Fundão's dam failure: An emergy perspective

In 2015, the ‘Fundão’ dam's failure in Brazil released 44 million m3 of tailings that traveled 670 km in the ‘Doce’ river watershed crossing 40 municipalities and two states until reaching the Atlantic Ocean. Since then, a public civil action (PCA) is responsible for litigation processes, and recently established a value of US$ 43.8 billion to repair losses and damages, a value that brings doubts about its accuracy in expressing the loses and damages of the disaster. This claims for alternative methods for its monetary quantification than the current tradicional economic ones. Among others biophysical approaches, the emergy accounting appears as a powerful tool due to its donor side perspective that objectively quantifies value and recognizes energy quality. This study aims to use emergy accounting as method to firstly identify and then quantify the impacts of ‘Fundão’ dam's failure, considering exclusively the negative direct and immediate impacts. Three categories are considered to quantify loses and damages: (I) suppressed stocks in the mud passage and deposition areas (MPDA), (II) social disruption, and (III) changes in landscape. For all the three scenarios of turnover times (Tt), results show that about 98% of total emergy in the suppressed stocks are related to (II) and (III), while only 2% in average is related to (I). This discrepancy highlights the importance of accounting for (II) and (III) since they are often disregarded or not directly considered by traditional economic approaches. From a macroeconomic perspective, the highest total emergy-based dollars (emdollar, EmUS$) found for scenario #3 reached EmUS$ 149.18 billion, a value 3.4 times higher than the US$ 43.8 billion established by PCA. This higher value is equivalent to the annual emergy demanded by the Ecuador economy with 18 million inhabitants. Rather than providing an accurate monetary value for the ‘Fundão’ disaster repair, this study contributes for the advancement of discussions about using biophysical methods such as emergy accounting that allows tracking all numbers for objective verification as alternative to the traditional economic approaches in quantifying losses and damages of high proportion disasters.

Impact of waste slag reuse on the sustainability of the secondary lead industry evaluated from an emergy perspective

Waste slag (WS) derived from the pyrometallurgical process of waste lead-acid battery (LAB) is becoming a potential contributor to environmental pollution. Therefore, WS treatment or disposal should be considered an integral part of waste LAB treatment systems to comprehensively analyze the sustainability of secondary lead industry. Given that emergy analysis (EmA) can evaluate all forms of energy, materials, and human services on a common basis by converting them into equivalents of one form of energy, our study proposes an emergy-based approach and several improved indicators. Unlike traditional emergy indicators, the output emergy and waste emergy in our approach were added into an improved emergy indicators. The improved indicators also converted emission impacts into equivalent emergy associated with economic activities, including the emergy of ecological services, emergy loss of affected natural resources, emergy losses associated with human health damage and land occupation. Next, four scenarios as study cases were evaluated using the proposed approach and indicators. Our study found that 1) the improved emergy indicators are more rigorous than their traditional counterparts; 2) although the reuse of WS raises the disposal costs (scenario C and scenario D), it can improve the environmental performance of waste LAB treatment systems, thereby greatly improving system sustainability; finally, the proposed approach can help policy-makers make decisions and guide enterprises to improve the overall performance of waste LABs treatment systems.

The Sustainability of Living in a “Green” Urban District: An Emergy Perspective

While urban areas hold great potential for contributing to sustainable development, there is a critical need to better understand and verify what measures improve urban sustainability. To achieve this, this project implements emergy synthesis to evaluate the environmental support to a building—called Smaragden—located in a certified “green” urban district in Uppsala, Sweden. Inputs to the building’s construction and maintenance phases are accounted for, as are flows supporting the residents’ everyday practices (i.e., urban life), on a yearly per capita basis. In this way, the relative importance of lifestyle issues versus the built environment is quantified and compared. Key focus areas are identified where efficiency and sustainability gains are most likely. The emergy synthesis detailed the top contributors to urban resource consumption and revealed that both the lifestyle and built environment in Smaragden are highly unsustainable, ranking poorly in terms of the emergy indices calculated, and, when considered from a global emergy perspective, overshooting resource consumption by more than 70 times. The paper therefore concludes that interdependencies of urban districts on systems at larger scales of society and environment need to be explicitly addressed and actively incorporated in urban policy and planning, and that design interventions are hence grounded in a systems perspective on urban sustainability.

Systems Thinking: Adopting an Emergy Perspective as a Tool for Teaching Green Chemistry

Green chemistry is the name of a need, that of encompassing chemistry research and the environmental, safety, health, and societal issues that have been creating unprecedent concerns at a global level. Green chemistry is a modern concept, as the label that represents the entry of chemical sciences in the realm of integrated sustainability studies. To do green chemistry research, we need approaches that take into account the use and availability of resources, as well as the direct or indirect impacts of the applications of new chemistry. Systems thinking is a powerful mindset for addressing the complexity of the interconnections between the traditional and the new aspects of chemistry research. Systems thinking can provide suitable and appropriate conceptual tools for the research, requiring that chemistry teaching provides the necessary familiarity with systemic concepts and practices. In this paper, an emergy (spelled with “m”) perspective is presented as suitable to address the green chemistry didactics toward a systemic conceptual framework, which is now more and more mandatory.

Accounting emergy-based sustainability of crops production in India and Pakistan over first decade of the 21st century

Agriculture is one of the main assets of Pakistani and Indian economies, employing in both countries about 50% of the total labour force. Thus, improving agricultural sustainability in the Indo-Pak region has important implications for the local population as well as the rest of the world that relies on food imports from these countries. This article investigates the drivers and consequences of changes in crop production sustainability in India and Pakistan from an emergy-based perspective, from 2001 to 2011. However, due to the numerous crops cultivated in these regions, a detailed calculation of unit emergy values (UEVs) for each crop was not possible, therefore the paper presents a balance at country level (based on literature data for the crops' UEVs), rather than a canonical emergy accounting.The emergy perspective was chosen to holistically evaluate and compare the environmental pressures caused by crop production in both countries. Emergy-based indicators were calculated based on the real time series of input renewable and non-renewable sources. The major findings of the work revealed that purchased renewable inputs, such as irrigating water, and purchased non-renewable inputs, such as agricultural labor, are the largest contributors among the total inputs in both countries. Labor accounted for 46.79% and 60.59% of total emergy input for crop production in India and Pakistan respectively. Overall, the production efficiency in India was greater than that in Pakistan. Emergy of crop production in Pakistan witnessed an increase of only 23%, whereas India saw an increase of 42% during the study period. Despite the lack of data on each specific agricultural process, this trend is an evidence of the fact that, if on one side the agricultural activities in the two countries were intensified to supply an increasing population, on the other side, although India performed better than Pakistan, the sustainability of the agricultural practices (from a nature-oriented perspective as assessed with emergy analysis) in both countries did not improve. . Trends of carrying capacity indicated that intensive means of agricultural production are threatening natural resources in both countries. This study empirically demonstrates the need to conserve natural resources, especially water, which have been rapidly declining in these two countries. Since both countries share these resources, this study represents an evidence for the need to cooperate for transboundary natural resource management.

Terrestrial transport modalities in China concerning monetary, energy and environmental costs

We investigate the terrestrial transport by pointing out the amount, the quality and the distribution of resources use among nine transport modalities at the national scale in China, under monetary, energy and emergy perspectives. The private car mode accounts for the largest share of the total monetary, energy and environmental resource investment of the terrestrial transportation, which means the lowest input-output and environmental efficiency. Consequently, improvement of energy and environmental efficiency in individual transport modes and the inevitable need to encourage the population to shift to public transport modes whit better performances remain crucial priorities. The most efficient transport modality depends on the evaluation method applied that assigns different priorities to specific aspects. From a monetary perspective, the most efficient passenger transport modality is the regular train followed by the high-speed train. In terms of cumulative energy demand, regular train and subway have the lowest unit cost among all passenger transport modes. Concerning the emergy accounting considering the environmental support, the urban bus for passengers and the regular train for commodity transport show the best performance per unit service. Even with needs for improved technical efficiency, the promotion of above less resource-intensive modalities in accordance with the different purposes would improve the global efficiency of the transportation system and offer better and larger transport options with the same resource investment.

Analysis of Environmental Carrying Capacity with Emergy Perspective of Jeju Island

Jeju Island experienced an approximately 42% increase in energy consumption from 2006 to 2015 and the demand for energy consumption is expected to continue to increase. Thus, Jeju Island is planning a project entitled “Carbon Free Island by 2030” to promote sustainable development and is required to estimate the environmental carrying capacity for future energy demand changes. The purpose of this study was to calculate the emergy inherent in Jeju Island’s energy, materials, and information in 2015 using the emergy analysis method and local characteristics. In addition, this study aimed to estimate the emergy indices to evaluate the environmental carrying capacity for sustainable development in 2005, 2015, and 2030 considering the future energy demand. This study’s outputs provide the environmental carrying capacity with emergy indices, such as the percent renewable (%Renew), emergy yield ratio (EYR), environmental loading ratio (ELR), sustainability index (SI), and carrying capacity of the population (CCP) for social and economic activities on Jeju Island, which are expected to be saturated. These findings show regions with heavy tourism require development strategies, including the concept of environmental carrying capacity.

Emergy Perspectives on the Environmental Performance and Sustainability of Small-Scale Gold Production Systems in Ghana

Small-scale gold mining is an important component of the Ghanaian economy but it has also caused enormous damage to local ecosystems. In this paper, an emergy analysis was conducted in Ghana to assess the environmental performance and the relative sustainability of two artisanal and small-scale gold production systems: alluvial “dig and wash” and underground “ghetto” mines. Results show that both production systems have high environmental impacts, as indicated by an environmental loading ratio (ELR) of 4.31 and environmental sustainability index (ESI) of 0.33 for the alluvial system and 2.53 and 0.52 for the underground system, respectively. Concerning the international trade balance, the emergy exchange ratios of the two systems are both lower than one, at, 0.23 and 0.33 for the alluvial and underground systems, respectively, indicating a significant amount of resource loss to foreign regions. This study could assist in the regulation of the small-scale mining sector bearing in mind the unsustainable nature of their activities. In addition, supporting miners to consider land rehabilitation ethics is urgently needed.

The solar transformity of heat and power in coproduction

Emergy analysis is a method for environmental accounting which presents the solar energy footprint of products. Processes with multiple products involve special calculation rules. If the co-products cannot be produced separately, the total input emergy is allocated on both products. Therefore an inseparable coproduction is penalized by the method. Yet, if the product can be produced separately in the system, the input emergy can be split for the products.Combined heat and power production (CHP) is a typical multi-production process, which is designed to meet the needs for the heat and power both. In earlier cogeneration emergy studies heat and power were treated as inseparable byproducts. As a result the transformity of electricity was often lower than the transformity of steam, which is not logical. Neither the approach could describe the co-production benefits to the independent production.Different alternatives of CHP are elaborated in this paper from emergy perspective. It was found that heat & power can be coproduced semi-independently employing condensing turbines with steam reduction but not by back pressure turbines. Therefore emergy allocation is possible only in condensing turbine systems. The choice of allocation method depends on the scope and purpose of study. Efficiency based allocation methods are recommended for general and local studies.As a case study two types of biomass CHP plants were analyzed. Work and alternative production emergy allocations were employed. In the reduction type of coproduction the transformities were the same as in independent production. Therefore no coproduction benefits were gained in this case. If steam extraction from the turbine is employed, the transformities vary as a function of the power to heat ratio. Minimum transformities appear at full extraction, which corresponds to employment of a back-pressure turbine. This is the most emergy efficient way of coproduction since any steam condensation is avoided.In the end main emergy contributors of biomass based coproduction were also discussed together with emergy indices.

Sustainability Evaluation of a Typical Cement Production Chain in China – An Emergy Perspective

Abstract Cement production has drawn great attention on account of its high consumption and emission during its production process, which impeded system sustainable development. It has been a hot issue to assess the potential effect of environmental emissions and optimizes the production process. In this paper, emergy analysis is conducted to quantify the quality and hierarchy of the resources, products and services and calculate the eco-environmental supports and socioeconomic investments for integrated ecological economic assessment from perspective of ecological economic system. Meanwhile, regarding production process, socio-economic system and ecological economic system, carbide slag substitution scenario, maize straw fuel substitution scenario, and waste heat recovery scenario are respectively set up to account the resource conversion and recycling utilization efficiencies with comparison to baseline, thus quantifying the energy conservation and emission mitigation effects for cement industry. Finally, oriented to the emergy-based sustainability indicator, the ternary emergetic diagram will be conducted to identify the optimization allocation mode of various ecological elements during the cement production process and overcome the difficulty of process optimization for traditional emergy analysis in the future work.

The Emergy Perspective of Sustainable Trends in Puerto Rico From 1960 to 2013

Emergy analysis quantifies the direct and indirect contributions of nature to human systems providing a sustainability assessment framework, which couples economic growth within biophysical constraints. In this study, Puerto Rico's sustainability was assessed with emergy flow dynamics from 1960 to 2013. During this period, the island shifted from an agriculture-based economy to an industrial base of manufacture and services (1960–1970). The emergy analysis indicated an exponential decline in sustainability during this period. From 1975 to 1992, the island became more industrialized and imported more goods and services. Since 1998, although more renewable production such as forest regeneration occurred, the rapid industrialization heavily relied on imported fossil fuels, goods, and services, resulting in a system that has not been self-sufficient, nor sustainable. The latest economic crisis and the most recently passed financial rescue bill represent an opportunity to redirect Puerto Rico towards a sustainable path with policies that decrease the ratio of imported y to exported emergy, and strategies that encourage efficient use of resources and local production based on the utilization of renewable sources within this U.S. territory.

Emergy-based Cost-benefit Analysis for Urban Biogas Project

Urban biogas project is important to satisfy the growing energy demands and improve the energy mix. Since the economic profits and environment impacts are essential factors for feasibility of construction and utilization of urban biogas projects, it is crucial to assess their economic and ecological performances. This paper modified the traditional cost-benefit analysis based on emergy accounting. Supporting environment which was neglected by conventional cost-benefit analysis was incorporated into the accounting boundary from emergy perspective. Moreover, the costs and benefits were calculated with emergy metric to quantify both economic and environmental contributions. The results showed that the payback period was 4.26 years due to the potential environment investments. The modified accounting framework through combining emergy theory with conventional cost-benefit analysis may unveil the real cost and benefit of urban biogas project via an energy numeraire.

Dealing with waste products and flows in life cycle assessment and emergy accounting: Methodological overview and synergies

This paper considers the different approaches taken in dealing with waste products and flows in Life Cycle Assessment (LCA) and Emergy Accounting (EMA), from a methodological point of view, and aims to develop more standardized and synergistic procedures. LCA deals with the waste issue from the point of view of the impact of their disposal, as well as the potential benefit (‘environmental credit’) afforded by the avoided extraction and processing of additional primary resources when waste is recycled or its energy content recovered. The ‘environmental burden’ associated to the entire production and consumption chain leading to the waste item is generally not included in LCAs of waste management systems, due to the boundary being placed – consistently with the intended goal – around the actual disposal processes (including recycling alternatives and associated environmental credits). Instead, Emergy Accounting, a donor-side approach with its implicit boundary set at the biosphere level, in principle keeps track of the entire supply-chain at all times, considering even waste flows as products (or co-products), and calculating their intensity factors and assessing their role within the ecosystem's web and hierarchy. However, when the focus is limited to evaluating processes under human control, within the narrower space and time boundary of human-dominated production and consumption processes, waste products can arguably be regarded as something to be recycled or disposed of to minimize the environmental burden. When this is the case, and particularly in comparative analyses, the emergy perspective thus becomes closer to the LCA perspective and interesting methodological synergies may emerge. A clearly defined set of emergy algebra rules for waste products and flows, and specifically for recycling, was found to be still lacking in the available emergy literature. We propose here that a better and more consistent methodological solution may be arrived at by leveraging the work done in LCA.

Environmental Accounting of Hydropower Construction in Upper Mekong River: An emergy Perspective

To meet surging energy demand, many countries have embarked on hydropower program to achieve renewable electricity production. However, environmental impacts of dam construction, such as landform changes and uneven sediments deposition, have made hydroelectric project a controversial issue. In this study, the long term ecological cost was taken into consideration for hydropower construction evaluation based on emergy method. Mekong River, as an international river, has attracted growing concern for the large-scale hydropower development on it. In this paper, Manwan dam, located in fragile region of upper Mekong River, is taken as a case study. The material and energy flows of hydropower system are evaluated on a common basis from a thermodynamic perspective. Emergy-based indicators are used to figure out beneficial contribution of hydropower and environmental pressure of dam construction. Compared with other traditional energy suppliers, the results show that Manwan hydropower exerts small stress on local ecosystem with a high efficiency of power generation.

Are all processes equally efficient from an emergy perspective?: Analysis of ecological and economic networks using matrix algebra methods

Matrix algebra methods have been developed in recent years to calculate transformities (energy quality indicators) from matrices of energy and mass flows in ecological and economic networks. This paper argues that the application of these methods by Emergy Analysts have unfortunately ignored the likelihood that in complex ecological and economic networks with many nodes and interconnecting pathways, that emergy efficiencies of all processes are expected in most cases to be different. Accordingly, this paper illustrates by a new method of emergy analysis that the emergy-based efficiency of most processes in the 1987 New Zealand energy system are not the same, and this is because we are dealing with a rectangular matrix of inconsistent equations. On the other hand, with square matrices (which usually represent consistent equations), the emergy-based efficiencies of the constituent processes are all the same, which is arguably no more than just an artefact of the aggregation required for the construction of these square matrices. This point is illustrated by the application of the Singular Value Decomposition (SVD) method to energy and mass flows for the Schlei Fjord ecosystem in Germany. The paper concludes by suggesting that differing emergy efficiencies of processes in ecological and economic systems are indicative of the system being in a non-equilibrium state which has some important implications in terms of its future application and contribution to Emergy Analysis theory. Of more practical importance, it is suggested in the paper, that the application of this SVD method provides a rigorous basis for pinpointing those processes that are most efficient from an Emergy perspective, which is important in terms of informing environmental management and the analysis of public policy options.

Emergy perspectives on the Argentine economy during the 20th century: a tale of natural resources, exports and external debt

Numerous approaches seek to incorporate the environmental dimension to macroeconomic indicators. In this study Emergy Accounting (EA), a methodology grounded in systems ecology and ecological economics, was used to assess changes in the ecological sustainability of the Argentine economy during the 20th century. Throughout the century, the proportion of Argentina's economy supported by renewable energy decreased from 67% to 55%. An exporter of commodities, Argentina provided buyers more emergy than it received in exchange. Argentina's international debt is still a burden, but in emergy terms, we calculated that the country has already paid its external obligations by 1985. The unfair emergy terms of trade for many developing countries are at the heart of the external debt issue. EA, integrating the economic and ecological values of commodities, may offer useful insights on how to achieve environmental justice for Argentina and other developing countries trading in the global economy.

Emergy Perspectives of Ecosystem Restoration in Korea

The emergy (spelled with an 'm') concept was introduced to provide a new insight into ecosystem restoration efforts in Korea. The emergy is defined as the available energy of one kind previously required directly and indirectly to make a product or service. It is an effort to evaluate the true contributions of natural resources to our economy. It tries to include both contributions from natures free works and human services to develop and process natural resources. The emergy evaluation can be used to select a restoration alternative that yields more to the economy with less stress to the environment, by comparing different alternatives with indices expressed in emergy. It can also be used to assess the success of ecosystem restoration projects. Pulsing dynamics in which a slow build-up of production is followed by a frenzied consumption in relatively short time period seems to be a general feature of all systems. Any ecosystem restoration effort, therefore, should consider the whole pulsing cycle for a successful implementation.