Vol. 1, No. 2 (2013): Regular Issue

Emergy, due to its unique ability to translate into a single metric the memory of the geobiosphere exergy (environmental work) supporting any (technological or natural) system, has the potential to offer a new perspective of environmental assessment to support decision-making. Previous work by a number of researchers has pointed out the expected advantages of taking a hybrid approach combining Emergy Evaluation (EME) and Life Cycle Assessment (LCA). In particular, emergy calculation using Life Cycle Inventory (LCI) databases and LCA matrix-based formulation is claimed to have the potential to increase the reliability of emergy-based evaluations and thereby the applicability of the emergy concept in environmental decision-making. The paper points out the main obstacles to overcome in order to reach this consistent integration, highlighting the progresses made so far in this direction, until the most recent practical and operational advancements.

Emergy, due to its unique ability to translate into a single metric the memory of the geobiosphere exergy (environmental work) supporting any (technological or natural) system, has the potential to offer a new perspective of environmental assessment to support decision-making. Previous work by a number of researchers has pointed out the expected advantages of taking a hybrid approach combining Emergy Evaluation (EME) and Life Cycle Assessment (LCA). In particular, emergy calculation using Life Cycle Inventory (LCI) databases and LCA matrix-based formulation is claimed to have the potential to increase the reliability of emergy-based evaluations and thereby the applicability of the emergy concept in environmental decision-making. The paper points out the main obstacles to overcome in order to reach this consistent integration, highlighting the progresses made so far in this direction, until the most recent practical and operational advancements.

Due to concurrent crises of energy and environment in urban areas, a systematic evaluation of urban energy security status is needed to construct a resource-saving and environmental-friendly society. This paper established an evaluation framework from the perspectives of energy supply, energy consumption, social-economic condition, environmental impact, and climate change. A modified grey relational analysis was also proposed to quantify the energy security degree of a city. The framework was then applied to Chongqing City to evaluate its energy security status during 2005—2010. Results showed that the security level of Chongqing kept increasing from 2005 to 2009. Due to the low energy security coefficient of the energy supply and climate change subsystem, a dramatic decline of energy security degree was observed in 2010. Finally, suggestions on the construction of secure energy system in Chongqing were put forward to shed light on policy making.

Due to concurrent crises of energy and environment in urban areas, a systematic evaluation of urban energy security status is needed to construct a resource-saving and environmental-friendly society. This paper established an evaluation framework from the perspectives of energy supply, energy consumption, social-economic condition, environmental impact, and climate change. A modified grey relational analysis was also proposed to quantify the energy security degree of a city. The framework was then applied to Chongqing City to evaluate its energy security status during 2005—2010. Results showed that the security level of Chongqing kept increasing from 2005 to 2009. Due to the low energy security coefficient of the energy supply and climate change subsystem, a dramatic decline of energy security degree was observed in 2010. Finally, suggestions on the construction of secure energy system in Chongqing were put forward to shed light on policy making.

Energy structure optimization is vital for urban sustainable development. In this study, a multi-objective model is developed to allocate various energy resources in various urban sectors under various scenarios, aiming to minimize the total system cost, environmental impact, and energy consumption. The environmental impact incurred during the energy lifecycle, including energy production, transportation, and consumption, is evaluated using the lifecycle assessment method. The economic loss of environmental pollution during the energy lifecycle is also incorporated in the economic objective. The model is applied to Beijing, in which four energy resources (coal, oil, natural gas, and electricity) are distributed among six sectors (agriculture, industry, construction, transportation, commerce, and household). Three scenarios are formulated from the base case scenario: i.e., the energy structure adjustment scenario, the energy structure adjustment with low carbon emission scenario, and the energy structure adjustment with low carbon emission and industrial structure adjustment scenario. The results indicate a decline in the proportion of coal to total energy consumption and an increase in the corresponding proportion for the other resources. It is concluded that further increasing the utilization of natural gas and electricity while reducing coal consumption, controlling energy consumption in industry, and strengthening carbon emission restrictions will help achieve more effective and eco-friendly energy use patterns based on a comparison of the environmental impact and economic loss of pollution under all scenarios. The optimization model could provide support for the planning and management of urban energy systems.

Energy structure optimization is vital for urban sustainable development. In this study, a multi-objective model is developed to allocate various energy resources in various urban sectors under various scenarios, aiming to minimize the total system cost, environmental impact, and energy consumption. The environmental impact incurred during the energy lifecycle, including energy production, transportation, and consumption, is evaluated using the lifecycle assessment method. The economic loss of environmental pollution during the energy lifecycle is also incorporated in the economic objective. The model is applied to Beijing, in which four energy resources (coal, oil, natural gas, and electricity) are distributed among six sectors (agriculture, industry, construction, transportation, commerce, and household). Three scenarios are formulated from the base case scenario: i.e., the energy structure adjustment scenario, the energy structure adjustment with low carbon emission scenario, and the energy structure adjustment with low carbon emission and industrial structure adjustment scenario. The results indicate a decline in the proportion of coal to total energy consumption and an increase in the corresponding proportion for the other resources. It is concluded that further increasing the utilization of natural gas and electricity while reducing coal consumption, controlling energy consumption in industry, and strengthening carbon emission restrictions will help achieve more effective and eco-friendly energy use patterns based on a comparison of the environmental impact and economic loss of pollution under all scenarios. The optimization model could provide support for the planning and management of urban energy systems.

This paper appraises the energy requirements for mineral production through an exergy approach taking into account the long-term decline in ore grades. In this context, the exergy replacement costs are defined as the exergy required for restoring mineral resources from a complete dispersed state where no deposits exist into the same conditions in which they were delivered by the ecosystems with the available technology. The exergy replacement cost is the point of reference in order to evaluate in a single variable, characteristics such as composition, concentration (ore grade) and the state of technology of mineral resources. With empirical data of energy requirements in mining as a function of the ore grade, the exergy replacement costs of cobalt, copper, gold, nickel and uranium are obtained. Additionally, a general expression of mining energy vs. ore grade is derived for those mineral commodities where no empirical data is available.

This paper appraises the energy requirements for mineral production through an exergy approach taking into account the long-term decline in ore grades. In this context, the exergy replacement costs are defined as the exergy required for restoring mineral resources from a complete dispersed state where no deposits exist into the same conditions in which they were delivered by the ecosystems with the available technology. The exergy replacement cost is the point of reference in order to evaluate in a single variable, characteristics such as composition, concentration (ore grade) and the state of technology of mineral resources. With empirical data of energy requirements in mining as a function of the ore grade, the exergy replacement costs of cobalt, copper, gold, nickel and uranium are obtained. Additionally, a general expression of mining energy vs. ore grade is derived for those mineral commodities where no empirical data is available.

Time series analyses have been proven to be useful in capturing tendencies of country’s economical behavior. The aim of this work is to investigate and compare time series of Brazilian and Italian economies on the basis of the emergy synthesis method. The main objective is to provide comprehensive indicators of carrying capacity, economic performance and wellbeing over time, pointing out the differences between a fast developing nation, Brazil, and a developed nation, Italy. Focus is placed on emergy indicators capable of accounting for societal metabolism and shedding light on conventional monetary assessments. Trade between Brazil and Italy is also investigated in order to stress issues of fair and equitable trade in terms of balanced emergy exchange. Emergy indicators show that Brazil now relies on a decreasing percentage of renewable resources, resulting in increasing environmental load and decreasing global sustainability. Results are even worse for Italy that keeps using much larger fractions of nonrenewable and imported resources. As for the trade between the two countries: in the year 2008, Brazil exported to Italy 5.68E+22 seJ mainly in the form of raw resources, while imported 1.78E+21 seJ of manufactured commodities, generating a huge unbalance in terms of emergy traded.

Time series analyses have been proven to be useful in capturing tendencies of country’s economical behavior. The aim of this work is to investigate and compare time series of Brazilian and Italian economies on the basis of the emergy synthesis method. The main objective is to provide comprehensive indicators of carrying capacity, economic performance and wellbeing over time, pointing out the differences between a fast developing nation, Brazil, and a developed nation, Italy. Focus is placed on emergy indicators capable of accounting for societal metabolism and shedding light on conventional monetary assessments. Trade between Brazil and Italy is also investigated in order to stress issues of fair and equitable trade in terms of balanced emergy exchange. Emergy indicators show that Brazil now relies on a decreasing percentage of renewable resources, resulting in increasing environmental load and decreasing global sustainability. Results are even worse for Italy that keeps using much larger fractions of nonrenewable and imported resources. As for the trade between the two countries: in the year 2008, Brazil exported to Italy 5.68E+22 seJ mainly in the form of raw resources, while imported 1.78E+21 seJ of manufactured commodities, generating a huge unbalance in terms of emergy traded.

Among the methods proposed to environmental management of productive activities, Life Cycle Assessment is one of the most integrated, complete and effective. The product assessed is the dental Carpule syringe. The aim of this work is to achieve a Streamlined Life Cycle Inventory (LCI) to quantify the electric energy consumption and the solid waste release from dental Carpule syringes manufacture. The methodological framework is based on ISO 14040/2006. The LCI covers the syringe life cycle from mining to disposal. The limits of the system include the stages of copper and zinc mining and ore beneficiation, the production of polyethylene used for syringe and needle packing, the production of steel for needles and syringe coils, and the use of the whole set by dentists. The functional unit was defined as 106 (one million) applied anesthesia. During improvement assessment, the proposed solutions allow reducing the energy consumption at about 20% in the manufacturing stage. The solid waste quantity may be reduced by almost 40 % in the manufacturing stage, equivalent to approximately 6.5 % of the total solid waste released during the entire life cycle of the Carpule dental syringe.

Among the methods proposed to environmental management of productive activities, Life Cycle Assessment is one of the most integrated, complete and effective. The product assessed is the dental Carpule syringe. The aim of this work is to achieve a Streamlined Life Cycle Inventory (LCI) to quantify the electric energy consumption and the solid waste release from dental Carpule syringes manufacture. The methodological framework is based on ISO 14040/2006. The LCI covers the syringe life cycle from mining to disposal. The limits of the system include the stages of copper and zinc mining and ore beneficiation, the production of polyethylene used for syringe and needle packing, the production of steel for needles and syringe coils, and the use of the whole set by dentists. The functional unit was defined as 106 (one million) applied anesthesia. During improvement assessment, the proposed solutions allow reducing the energy consumption at about 20% in the manufacturing stage. The solid waste quantity may be reduced by almost 40 % in the manufacturing stage, equivalent to approximately 6.5 % of the total solid waste released during the entire life cycle of the Carpule dental syringe.

Agricultural systems operate in the interface between environment and human economy, combining the use of natural and purchased resources in food production. With the aid of the ternary diagram, data of agricultural systems taken from literature are organized in order to evidence the influence of the type of culture and of the analyst’s criteria on the results of environmental accounting in emergy. All the systems represented in the ternary diagram determine a qualitatively well-defined region, less or more extended according to the case. Points defined for the emergy coordinates were localized in defined regions observed in the diagram. Emergy accounting is presented as a method able to environmentally characterize production systems in a robust way, even with variations in analyst’s criteria and data nature or origin. It is shown that the results of environmental accounting obtained with the use of the emergy methodology are only slightly influenced by the analyst’s criteria. On the other hand, the ternary diagram appears as an interesting graphical tool to determine finding and checking robustness of emergy accounting. The robustness of emergy methodology is remarkable.

Agricultural systems operate in the interface between environment and human economy, combining the use of natural and purchased resources in food production. With the aid of the ternary diagram, data of agricultural systems taken from literature are organized in order to evidence the influence of the type of culture and of the analyst’s criteria on the results of environmental accounting in emergy. All the systems represented in the ternary diagram determine a qualitatively well-defined region, less or more extended according to the case. Points defined for the emergy coordinates were localized in defined regions observed in the diagram. Emergy accounting is presented as a method able to environmentally characterize production systems in a robust way, even with variations in analyst’s criteria and data nature or origin. It is shown that the results of environmental accounting obtained with the use of the emergy methodology are only slightly influenced by the analyst’s criteria. On the other hand, the ternary diagram appears as an interesting graphical tool to determine finding and checking robustness of emergy accounting. The robustness of emergy methodology is remarkable.