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In this paper, attention is focused on the analysis and optimization of energy flows in networked systems via a fluid-dynamic approach. Considering the real case of an energy hub, the proposed model deals with conservation laws on arcs and linear programming problems at nodes. Optimization of the energy flows is accomplished by considering a cost functional, which estimates a term proportional to the kinetic energy of the overall system in consideration. As the real optimization issue deals with an integral formulation for which precise solutions have to be studied through variational methods, a decentralized approach is considered. First, the functional is optimized for a simple network having a unique node, with an incoming arc and two outgoing ones. The optimization deals with distribution coefficients, and explicit solutions are found. Then, global optimization is obtained via the local optimal parameters at the various nodes of the real system. The obtained results prove the correctness of the proposed approach and show the evident advantages of optimization procedures dealing with variational approaches. [ABSTRACT FROM AUTHOR]

The article considers the mechanisms of the formation of transverse energy flows in polychromatic fields with different structures. It is shown that the magnitude of the Poynting vector transverse component and the angular momentum for symmetric polychromatic beams are the same as in coherent monochromatic fields. Changes in the characteristics of energy flows due to the transformation and destruction of beam symmetry are demonstrated. The data of computer ulation are presented. [ABSTRACT FROM AUTHOR]

Purpose -- The research aim of the article is the analysis of advanced/developed and developing countries in the context of sustainable development, using invariant coordinate system in energy units, as well as the impact of structural changes in the economy affect the possibility of transition to sustainable development and creation post-industrial society. Research methodology -- In order to achieve the aim were applied the method of socio-economic systems power changes analyzing in the frame of structural economic Kaldor model of GDP and the energy flows models. Finding -- The advanced countries have seen a trend of "zero growth" and a decrease in useful energy production in the last 10 years. These countries have high labor productivity, technological level and diminishing potential for sustainable development. China is in the stage of "growth and development" and has great potential. Data calculated by the authors of the article correlates with the findings of the Kaldor model. Research limitation -- The initial interpretation of the calculated data of France, Germany, Japan, USA, European Union and China was made. Countries have been analyzed in the period from 1990 to 2019. The data of the Central Statistical Office of EU and the World Bank were used. Practical implications -- The results of the study can be used to further planning and design of transition to sustainable development for advanced and developing countries. Originality/Value -- within the framework of the approach, an invariant coordinates system in energy units is proposed and the main parameters for assessing the potential of growth and sustainable development for advanced countries were formed. [ABSTRACT FROM AUTHOR]

Purpose – The research aim of the article is the analysis of advanced/developed and developing countries in the context of sustainable development, using invariant coordinate system in energy units, as well as the impact of structural changes in the economy affect the possibility of transition to sustainable development and creation post-industrial society. Research methodology – In order to achieve the aim were applied the method of socio-economic systems power changes analyzing in the frame of structural economic Kaldor model of GDP and the energy flows models. Finding – The advanced countries have seen a trend of “zero growth” and a decrease in useful energy production in the last 10 years. These countries have high labor productivity, technological level and diminishing potential for sustainable development. China is in the stage of “growth and development” and has great potential. Data calculated by the authors of the article correlates with the findings of the Kaldor model. Research limitation – The initial interpretation of the calculated data of France, Germany, Japan, USA, European Union and China was made. Countries have been analyzed in the period from 1990 to 2019. The data of the Central Statistical Office of EU and the World Bank were used. Practical implications – The results of the study can be used to further planning and design of transition to sustainable development for advanced and developing countries. Originality/Value – within the framework of the approach, an invariant coordinates system in energy units is proposed and the main parameters for assessing the potential of growth and sustainable development for advanced countries were formed.

The contemporary scientific and technical community claims that the new development paradigm will be based on the priority of the universal laws of nature, the principles of ecological economics and the widespread use of digital transformation. The analysis of the sustainable development strategy Latvia 2030 and the presented changes in the value of indicators showed that, it is quite difficult to put together a common unified picture of Latvia's movement towards sustainable development. The main goal of the article is to present a new approach to the assessment of sustainable development and to monitoring system, using a system's power changes analysis method. In the context of a Latvian sustainable development strategy, the authors presented the results of the formalisation of new approach to the sustainable development monitoring, using an invariant coordinate system in units of power (energy flow) in compare with calculated data in monetary terms. Calculations and the initial interpretation of the results of Latvia as well as of the five EU countries from the Baltic Sea region – Denmark, Sweden, Finland, Estonia and Lithuania – were carried out for the period 1990.-2019. The presented indicators of sustainable development show that achieving the strategic goals of Latvia 2030 would be very difficult without any serious internal and external incentives. The results can provide a basis for creation of the development strategy both the country as a whole and each region separately. [ABSTRACT FROM AUTHOR]

Uncovering relationships between landscape diversity and species interactions is crucial for predicting how ongoing land‐use change and homogenization will impact the stability and persistence of communities. However, such connections have rarely been quantified in nature. We coupled high‐resolution river sonar imaging with annualized energetic food webs to quantify relationships among habitat diversity, energy flux, and trophic interaction strengths in large‐river food‐web modules that support the endangered Pallid Sturgeon. Our results demonstrate a clear relationship between habitat diversity and species interaction strengths, with more diverse foraging landscapes containing higher production of prey and a greater proportion of weak and potentially stabilizing interactions. Additionally, rare patches of large and relatively stable river sediments intensified these effects and further reduced interaction strengths by increasing prey diversity. Our findings highlight the importance of landscape characteristics in promoting stabilizing food‐web architectures and provide direct relevance for future management of imperilled species in a simplified and rapidly changing world. [ABSTRACT FROM AUTHOR]

In this paper, attention is focused on the analysis and optimization of energy flows in networked systems via a fluid-dynamic approach. Considering the real case of an energy hub, the proposed model deals with conservation laws on arcs and linear programming problems at nodes. Optimization of the energy flows is accomplished by considering a cost functional, which estimates a term proportional to the kinetic energy of the overall system in consideration. As the real optimization issue deals with an integral formulation for which precise solutions have to be studied through variational methods, a decentralized approach is considered. First, the functional is optimized for a simple network having a unique node, with an incoming arc and two outgoing ones. The optimization deals with distribution coefficients, and explicit solutions are found. Then, global optimization is obtained via the local optimal parameters at the various nodes of the real system. The obtained results prove the correctness of the proposed approach and show the evident advantages of optimization procedures dealing with variational approaches.

Due to decrease of oil reserves, the international commitment for the reduction of pollutant emissions and environmental protection, renewable energy sources are intensively studied, including solar energy applications. However, solar energy is not constant and one possible alternative are solar hybrid thermosolar power plants. A hybrid solar gas turbine has three subsystems: a solar concentrator with heliostat field and central tower receiver, a combustion chamber, and a regenerative gas turbine. A previous thermodynamic analysis allowed shows an energy and exergy study of the plant, from a thermodynamic model of the system that has a method of solar resource estimation. However, this analysis did not allow evaluation of the energy losses in the system components, although the original model considered the typical irreversibilities of these cycles. This work aimed to develop a thermodynamic model that estimates the energy losses in the subsystems and the solar hybrid gas turbine components from a few parameters. The model estimated the energy losses for a Brayton cycle hybrid solar thermal plant throughout the day July 20 in Barranquilla, Colombia. A Dymola compiler in Modelica language was used to evaluate the model, which facilitates the estimation of the results at different times of the day. In this case, the computations were performed hourly throughout the day. In the results, energy losses were 16 % in the solar concentrator when the solar resource was the maximum at noon and close to 1 % in the combustion chamber. Therefore, the hybrid solar Brayton cycle system is technically feasible and reduces fuel consumption. Consequently, it is important to continue developing concentration systems and reduce their energy losses. [ABSTRACT FROM AUTHOR]

Research on urban metabolism (UM) focuses on cities' material and energy systems by identifying paths and transformation processes of all kinds of flows in urban contexts. In particular, scientific studies aim to trace the origin and destination of materials, energy, water, emissions and waste flows in order to understand relationships between cities and other spatial areas (hinterlands) that lead to political, social and environment consequences. This research paper aims to analyze complex power relationships between cities and their hinterlands. In particular, the objective is to understand the nature of these socio-material links. Are they based on synergies and cooperation, or, on the contrary, on unbalanced power and conflicts? We propose an approach which combines methodologies with the tools of Energy Flow Analysis (EFA) and semi-structured interviews, in order to develop a “political-industrial ecology” of energy metabolism (Breetz 2017; Cousins and Newell 2015). We have studied the Saint-Nazaire metropolitan area, which is constituted by an urban area and a port zone. This harbor consists in a complex network of highly energy-intensive industrial sites operating in the steel, petrochemical and agri-food industries. Based on an analysis of energy flows, institutional policies and professional practices, we have identified several situations of metabolic links that exist simultaneously. In conclusion, the metabolic relationships' framework is useful to understand how the “hinterlands-city” relationships shape and are shaped by the city's metabolism.

Introduction. Ensuring the required parameters and characteristics of electromagnetic radiation of lighting irradiation facilities for greenhouses is an important task to improve the efficiency of energy use and the characteristics of crop production. The aim of the work is to determine the effective operation mode of technological irradiation scheme with separation of energy flows in lighting systems of industrial greenhouses. Materials and Methods. In the developed model of the irradiation technological scheme, constructive decisions make it possible to divide the energy flows into components and to control these flows. It has been proposed that separate regulation of the voltage on the irradiator and the fan can be used to create conditions for changing the values of separate spectral lines of radiation in order to further assess the effect of these changes. Results. We obtained the results on the change of PPFD distribution depending on the voltage on the greenhouse irradiator from 198 to 242 V and the air temperature near the lamp from 38 to 47°C. The comparison of averaged PPFD values in the studied modes with the PPFD value in the nominal mode for these ranges allowed determining the mode at voltage 220 V and the air temperature near the lamp from 43 to 47°C as a rational for practical use in technological irradiation schemes with energy flows separation in the lighting systems of industrial greenhouses. Discussion and Conclusion. The development and application of rational modes for operation of greenhouse irradiators, taking into account the modes of network and lamp is the basis for greenhouse production with the use of alternative thermal energy.

The paper focuses on key questions to the contemporary challenges call for a shift from the current linear economic model to models that will see nature as a life support system for social prosperity within the ecological economy paradigm and digital transformation. The aim of the article is to present the model of open non-equilibrium socio-economic complex system and its sustainability conditions formalization in terms of an invariant coordinate system. As well as to present the results of a formalization of sustainable development monitoring using the energy flows changing analysis approach, and the impact of condition of digital transformation. The authors carried out an assessment of sustainable development and analyzed indicators of sustainable development and the level of digital and their correlation. When calculating the parameters, Eurostat data and UN databases were used. The authors presented the results and initial interpretation of the follow countries France, Sweden, USA, China, Russia. The paper reinterprets the significance of the digital transformation concept and further elaboration of the power approach for monitoring the socio-economic system development.

Organic livestock farming can help to make agroecosystems more sustainable. We hypothesized, however, that not all organic farm management models contribute in the same way. One way to assess this is to perform energy analyses of livestock farms, establishing not only how efficient the systems are at producing goods and services for society, but also the investment in the fund elements that sustain the system itself and its environmental sustainability. But to be effective, such studies must go beyond a classic input-output analysis: they must also address the internal energy flows that maintain the quality of agroecosystem fund elements as well as some ecosystem services they provide. In the present work, we implemented the energy return on investment methodology and combined classic economic energy indicators with new agroecological measurements that allow to assess the quality of agroecosystem fund elements. We applied these agroecological energy indicators to organic pig and beef cattle farms with the aim of differentiating the organic forms of management that best contribute to sustainability. This is the first time that this methodology has been applied on pig farms. Based on this methodology, we identified five management models of organic beef and pork production in Mediterranean systems that presented different degrees of sustainability. The most efficient and environmentally sustainable model was the breeding of beef cattle/pigs in agrosilvopastoral dehesa pasturelands. These dehesa systems include farms that are highly self-sufficient in terms of animal feed as well as farms that import certain feed stuffs because they fatten animals until slaughter. It was the breed together with the stocking densities that conditioned livestock functionality more than the livestock species orientation. The results allowed us to distinguish the various forms of organic livestock management implemented and their degree of sustainability, thus providing public policy orientations on the most efficient models. [ABSTRACT FROM AUTHOR]

The aim of the article is to explain holistically the main provisions of sustainable development in the nature-society-human system based on the methodology for analyzing changes in energy flows and the power of socio-economic systems. The authors consider the development of society as a creative process aimed at changing the direction and speed of free energy flows (useful power) in Space and Time. They also consider sustainable development in the nature-society-human system to be consistent with the laws of the global evolution of living nature and the laws of the historical development of humankind. The paper focuses on key questions concerning the new concepts of sustainable development; the methodology for designing the sustainable development using the concept of energy flows in open, non-equilibrium stable systems and power change analysis approach. The results of the main positions of the models and their interpretation are presented based on the statistical data of United States of America (USA) in the period of 1960–2021. One of the most important primary things in order to bring about changes in people's thinking, understanding and attitude towards sustainability issues is their education in different forms – formal education and non-formal education opportunities. Creating an interdisciplinary approach and explaining sustainability as a set of economic, social and ecological factors also play a crucial role in raising public awareness of sustainability issues. [ABSTRACT FROM AUTHOR]

In this paper, we provide an in-depth analysis of factors determining energy import demand of EU countries. We suggest a novel approach to study the role of renewable versus non renewable energy sources in shaping the demand for energy imports. The aim of the paper is twofold. First, we provide a comprehensive analysis of the EU energy market structure using country-by-country I–O tables to show the rate of interdependency between EU member states in terms of renewable and non renewable energy flows. Second, we investigate on the role of renewable energy sources in reducing energy dependency in EU countries. The econometric analysis uses data from 26 EU countries observed between 2007 and 2016 available from the Eurostat energy statistics database. The descriptive analysis of I–O electricity tables shows some degree of heterogeneity between countries in terms of energy in- and out-flows. Such heterogeneous market structure suggests the use of panel models in the econometric analysis. Moreover, a lasso regression method has been employed for variables selection to avoid the collinearity. The results show that benefits may arise from replacing energy imports with domestic energy production and from reducing energy dependency rate. Moreover, if import substitution occurs with domestic renewable energy sources additional positive effects are produced in terms of either energy dependency, energy security and sustainable development. [ABSTRACT FROM AUTHOR]

The aim of this study is to provide insights regarding the economic viability of and energy flows within a renewable energy community based on a linear optimisation model with peer-to-peer electricity trading. Different technologies, such as PV, heat pumps, electric vehicles, and a community battery storage, are modelled. With the objective of achieving a cost-optimal solution for the whole community, the individual impacts of different technologies, as well as their permutations, are investigated. Therefrom, financial and environmental advantages and disadvantages for individual participants and the whole community can be derived. The results indicate that customers who are equipped with a combination of PV systems, heat pumps, and EVs achieve better individual results compared to those with lower levels of technology. Especially when heat pumps are involved, the amounts of PV electricity generated can be used with high efficiency, increasing the benefits of energy community participation. Moreover, the higher the level of electricity-based technologies within the community is, the lower the conventional grid feed-in becomes. An additional implementation of a community battery storage can further reduce these amounts and, thus, the grid burden. Apart from the financial benefits, the installation of additional assets and, thus, reduced grid feed-in contribute to the reduction of CO2-emissions. This study's results can aid in making decisions regarding investments and energy community composition, as well as in the funding decisions of policymakers. [ABSTRACT FROM AUTHOR]

When it comes to the investigation of key ecosystems in the world, we often omit salt from the ecological recipe. In fact, despite occupying almost half of the volume of inland waters and providing crucial services to humanity and nature, inland saline ecosystems are often overlooked in discussions regarding the preservation of global aquatic resources of our planet. As a result, our knowledge of the biological and geochemical dynamics shaping these environments remains incomplete and we are hesitant in framing effective protective strategies against the increasing natural and anthropogenic threats faced by such habitats. Hypersaline lakes, water bodies where the concentration of salt exceeds 35 g/l, occur mainly in arid and semiarid areas resulting from hydrological imbalances triggering the accumulation of salts over time. Often considered the 'exotic siblings' within the family of inland waters, these ecosystems host some of the most extremophile communities worldwide and provide essential habitats for waterbirds and many other organisms in already water‐stressed regions. These systems are often highlighted as natural laboratories, ideal for addressing central ecological questions due to their relatively low complexity and simple food web structures. However, recent studies on the biogeochemical mechanisms framing hypersaline communities have challenged this archetype, arguing that newly discovered highly diverse communities are characterised by specific trophic interactions shaped by high levels of specialisation. The main goal of this review is to explore our current understanding of the ecological dynamics of hypersaline ecosystems by addressing four main research questions: (i) why are hypersaline lakes unique from a biological and geochemical perspective; (ii) which biota inhabit these ecosystems and how have they adapted to the high salt conditions; (iii) how do we protect biodiversity from increasing natural and anthropogenic threats; and (iv) which scientific tools will help us preserve hypersaline ecosystems in the future? First, we focus on the ecological characterisation of hypersaline ecosystems, illustrate hydrogeochemical dynamics regulating such environments, and outline key ecoregions supporting hypersaline systems across the globe. Second, we depict the diversity and functional aspects of key taxa found in hypersaline lakes, from microorganisms to plants, invertebrates, waterbirds and upper trophic levels. Next, we describe ecosystem services and discuss possible conservation guidelines. Finally, we outline how cutting‐edge technologies can provide new insights into the study of hypersaline ecology. Overall, this review sheds further light onto these understudied ecosystems, largely unrecognised as important sources of unique biological and functional diversity. We provide perspectives for key future research avenues, and advocate that the conservation of hypersaline lakes should not be taken with 'a grain of salt'. [ABSTRACT FROM AUTHOR]

Comprehensive studies assessed the role of inputs on efficiency parameters in rose production systems in open-field and protected conditions at Bengaluru, India during 2017–2020. Results highlight that precision application of critical inputs based on assessment of crop demand contribute to 4-fold increase in flower yields and substantial accumulation of above-ground biomass in open-grown roses. The net return per each unit investment can be trebled in loose flower rose and doubled in cut flower rose. Critical inputs such as nutrients and water account for maximum energy consumption (93.5–94.7%). Loose flower rose registers better energy efficiency indices than cut flower rose. In protected condition, variations in flower yields, carbon stocks and energy efficiency indices are significant among rose genotypes. Arka Swadesh genotype is efficient in resource use accruing maximum net benefit per rupee investment. Nutrients are the maximum consumers of energy (41.2%) followed by irrigation (20.9%). In protected condition, the productivity levels are similar among nutrient levels implying lesser nutrient application is sufficient for rose due to higher efficiency indices and optimum soil fertility. The results imply that rose production systems are highly productive and sustainable at optimum input levels and would reduce environmental pollution due to higher resource use efficiencies.

Biological invasions are a worldwide threat to the aquatic systems and have the potential to homogenize entire foodwebs and shift species abundance distributions to more skewed ones. Invasion impacts include effects on the foodweb structure and ecosystem functioning leading to a loss in native fish biodiversity and commercially important fisheries in many open water systems. The impacts of invasives are generally devastating as they spread in the foodweb with each species potentially interacting with multiple species. The foodweb modeling studies conducted in different inland aquatic ecosystems show that not all exotics cause a detrimental effect on the resilience of an ecosystem. Information on the foodweb structure and ecosystem properties is a prerequisite for formulating management protocols for conserving biodiversity, enhancement programmes and sustaining fisheries. The present paper reviews the impacts of invasive fishes in Indian aquatic ecosystems in the context of a changing foodweb scenario due to exotic fish species invasions. The information generated here could be applied for future research on similar ecosystems for deducing management actions. [ABSTRACT FROM AUTHOR]

This paper presents energy flows management of multiple electric vehicles charging and its impact on a microgrid. The studied low voltage grid comprises also two photovoltaic generators and non-dispatchable loads. Three concepts using electric vehicles batteries as a distributed storage and bidirectional energy transfer in the Smart Grid are considered: Vehicle to Home, Vehicle to Vehicle and Vehicle to Grid. The potential for implementation of flexible microgrid energy flow management strategy for reduction of peaks in power consumption, absorption or production of reactive power (when required) and improving the power quality in the studied microgrid are estimated. For this purpose a set of usual load profiles of electric vehicle charging modes are studied and presented. Simulation results demonstrate the potential of electric vehicles as a flexible load and energy storage for peak load shaving in microgrids. DOI: 10.5755/j01.eie.25.1.22730

In manufacturing, there is increasing recognition of the need to increase energy efficiency, both to reduce process cost and improve carbon footprint. In order to achieve this, it is necessary to understand how manufacturing systems use energy directly and indirectly. These types of analyses have been carried out at the process level for traditional machining processes, as well as at the factory level to understand macroenergy flows and bottlenecks. Other researchers have accomplished considerable energy optimization work for laser processing. However, the emphasis of this work has been on the optimization of the laser–material interaction. This focus has overlooked the whole system viewpoint and the significance of supporting equipment. Laser welding, using a 300 W fiber laser, was chosen as the subject for this study; first, due to its ubiquity in many high-value manufacturing industries and second due to its potential as a gateway into other manufacturing processes, such as directed energy deposition and additive manufacturing. In this paper, the initial work was to produce a framework for categorizing the process states and subsystems found in a standard or generic laser machine tool. An electrical energy meter was used to measure the energy consumption for individual subsystems when creating autogenous weld tracks in 316L stainless steel. Analysis of these data showed that the laser is only 18% of the total power consumption, the most significant being the water-cooling subsystem (37%). Reported here is a complete analysis of laser welding energy efficiency at a system level. This primary analysis of current equipment typical energy consumption can be used to identify future strategies for energy efficiency improvements beyond the direct laser interaction. By focusing on the most energy-inefficient parts of the system, the greatest potential for improvements to the carbon footprint of laser processing can be quantified. [ABSTRACT FROM AUTHOR]

As the electrification of vehicles keeps being widespread, and facing the impossibility of storing big amounts of electrical energy, the challenge of controlling and adapting the electricity supply and demand has become a necessity. Therefore, electric vehicles could be an optimal solution for the storage and the retrieval of energy depending on the supply and demand of electricity. Thus, this study proposes an energetic strategy based on a multi-objective and multi-criteria optimization algorithm related to the control of the energy flows between the electric vehicles and the grid, home or building depending on the electricity supply and demand. The main focus at this stage involves the optimization of the vehicles' charging mode. Hence, in this paper, the multi-objective optimization proposed is first implemented through the presentation of its algorithm and the description and modeling of its objective functions and their corresponding constraints. Then, the genetic algorithm optimization approach is adopted for the charging process of the study to find the optimal solution for each objective function. Besides, the weighted sum approach is applied after the normalization of all the fitness functions and several case studies are carried out to find the optimal solutions based on the priority of specific objectives over the others. Once all calculations are done, a simulation via Matlab software is performed and the results are discussed and compared. The simulation of the results has verified the theoretical calculations proving the effectiveness of the proposed methodology. However, as some of the calculated optimal solutions of the system seem to be conflicting, the prioritization of some objectives over others had to be operated in order to figure out a global solution for the multi-objective system. Thus, as a compromise had to be applied for the calculation of quasi-optimal solutions that would converge towards the Pareto-front, the decision maker's preference would set the final solution using the weighted sum approach. [ABSTRACT FROM AUTHOR]

In the last decade, renewable energy supply has gained increasing interest, as it can contribute to the diversification of the energy mix. Energy flexibility offers consumers the opportunity to benefit from fluctuating energy prices, connected to the volatility of wind and solar power. This paper aims at mapping flexibility strategies and their requirements in the process industry environment. The conception of flexibility measures requires a characterization of energy flows, in order to identify hotspots and estimate the flexibility potential. An integrated methodology has been developed with the purpose of supporting investment decisions for a case-study in the paper production sector in Germany. [ABSTRACT FROM AUTHOR]

The breakdown of the USSR was followed by appearance of new independent states on the Caspian for which the development of new hydrocarbon deposits and their export to foreign markets opened new horizons of development. This paper investigates the results of pipeline rivalry in the Caspian region that started after the USSR disintegration.

Purpose – At the 21st Conference of the Parties to the United Nations Convention on Climate Change (COP 21) in Paris, 195 governments reached an agreement pivotal not only for countries but also for companies. The Paris Agreement makes it impossible to practice business as usual. The transition to a low-carbon coffee industry could be achieved by fostering corporate sustainability. Accordingly, the purpose of this paper is to provide empirical evidence of how to adopt the principles of Paris Agreement by enhancing the corporate sustainability of a Mexican coffee-roaster company using the inventory phase of the life cycle assessment tool. Design/methodology/approach – The data collection process followed the requirements of the International Reference Life Cycle Data System Handbook, developed by the Institute for Environment and Sustainability in the European Commission Joint Research Centre, and data on packaging materials and energy production were drawn from a commercially available database in the LCA software SimaPro. Findings – Compiling data on the energy of the firm’s material flows in a firm revealed opportunities to improve energy efficiency and to reduce greenhouse gas emissions. The results of the inventory analysis can be used to evaluate the specific environmental impacts of the coffee-roasting process at this Mexican coffee company. Data compilation activities for energy flows identified the need to install liquefied petroleum gas measuring devices and individual measuring devices for electricity consumption in different areas of the coffee plant. It is recommended that, while implementing this option, the company also develop an energy management program to achieve energy efficiency. Practical implications – The inventory data in this case study permit comparisons of the current state of the system studied and its possible future states and offer stakeholders relevant information on resource use. Similarly, the project results provide the basis for future research on environmental performance in the coffee industry in Mexico and for the development of policies regarding the production process in the coffee supply chain. Consequently, this research can help fulfil Mexico’s commitment to the Paris Agreement. Social implications – Reaching the goal of the Paris Agreement will require gathering key information for each single company. The current case study has provided key data to foster the principles of sustainability in the Mexican coffee industry to help this sector to transit toward sustainable development, which is a new demand of the Mexican society. Even though it may seem simple, this is the hardest step for enhancing stakeholder involvement in corporate sustainability. Originality/value – The main contribution of this research to science and practice is to confirm that fostering corporate sustainability is easier and more feasible when energy flow information is available.

The smart grid technology permits the revolution of the electrical system from a conventional power grid to an intelligent power network which has led the improvements in electrical system in terms of energy efficiency and sustainable energy integration. This study presents the energy management/coordination scheme for domestic demand using the key strategy of smart grid energy efficiency modelling. The structure consists of combining renewable energy resources, photovoltaic (PV) and wind power generation connected to the utility grid with energy storage system (ESS) in an optimal control manner to coordinate the power flow of a residential home. Based on the demand response schemes in the framework of real-time electricity pricing, this work designs a closed-loop optimal control strategy that is created by the dynamic model of the ESS to compute the system performance index, which is formulated by the cost of the energy flows. A dynamic distributed energy storage strategy (DDESS) is implemented to optimally coordinate the energy system, which reduces the total energy consumption from the main grid of more than 100% of the load demand. The designed model introduces a payback scheme while robustly optimising the energy flows and minimising the utility grid's energy consumption cost.

Highlights • 88% of the energy flowing into Jämtland renewable. • 15.200 TJ drives Jämtland with 63% renewable part. • Transportations major issue to reach sustainability. • Energy efficiency Forestry sector 700%. • Energy efficiency Reindeer herding 5%. Abstract An analysis of energy and material flows has been elaborated for the Swedish region Jämtland with the aim of monitoring and comparing regional sustainability by following the work energy flow method developed in a study of the Danish island of Samsø (Nielsen & Jørgensen, 2011). In the region of Jämtland about 46,000 TJ of energy flows into society, of which 88% is renewable. From this an amount corresponding to 30,800 TJ is exported as electricity from the region, while another 410 TJ is exported as waste to be incinerated. The remaining part, about 15,200 TJ (63% renewable), drives Jämtland. From an energy flow perspective, the most important production from the region, apart from electricity production, is biomass from the forest: 49,000 TJ estimated as energy content in the biomass harvested. Another 55,000 TJ is added to the standing biomass every year as forest growth (only productive forest land area has been calculated). Some suggested indices of sustainability have been calculated and Jämtland shows high values. However, it will be a challenge to transform the quite large transport sector of Jämtland, and therefore the potential to become fully sustainable (ref to indexes used for the Samsø study) might not be quite as high. In order to reduce the use of non-renewable energy, a major conversion of the transport fleet is needed, and this should be given high priority. The private sector is the largest single user of non-renewable energy (2,200 TJ). One successful transition is the Swedish diesel mix with 19% FAME/HVO derived from vegetable or animal sources and regarded as renewable. The consumption of FAME/HVO is predicted to increase significantly, increasing the importance of the forest as a source. A sustainability analysis based at work energy flows shows for both Samsø and Jämtland that large natural resources producing a high work energy output combined with low work energy use due to low population density, gives high sustainability indicators. This indicates that regions with high population density and the absence of natural resources (high import), as in most regions in the world, will show low sustainability indicators. [ABSTRACT FROM AUTHOR]

Rice-fish system is the first globally important agricultural heritage system (GIAHS) and could be a potential option to improve modern rice production. This paper investigates energy flows and economic profits of two rice production agroecosystems in China. Results suggest that total energy input in rice-turtle-fish co-culture (RTF) was 18,889.63 MJ ha−1, less than that of rice monoculture (RM) (20,289.44 MJ ha−1). Total energy output in RTF was 82,836.57 MJ ha−1, higher than that of RM (77,221.21 MJ ha−1). The product safety index (PSI) in RTF and RM were −0.23 and −0.77, respectively, which indicated the products safety potential in RTF was higher than that of RM. The energy sustainable development index (ESI) in RTF and RM were 9.03 and 0.66, respectively, which illustrated RTF has abundant developmental potential, while RM is more of a consuming-type ecosystem. The output/input, gross profits, and net profits in RTF were 5.17, 99,531.30 CNY, and 98,729.96 CNY, respectively, all higher than that of RM (4.58, 11,335.67 CNY and 11,034.33 CNY, respectively). Consequently, RTF has greater potential to reduce agro-chemicals, improve energy use efficiency, and increase economic profits compared to RM. [ABSTRACT FROM AUTHOR]

This paper presents energy flows management of multiple electric vehicles charging and its impact on a microgrid. The studied low voltage grid comprises also two photovoltaic generators and non-dispatchable loads. Three concepts using electric vehicles batteries as a distributed storage and bidirectional energy transfer in the Smart Grid are considered: Vehicle to Home, Vehicle to Vehicle and Vehicle to Grid. The potential for implementation of flexible microgrid energy flow management strategy for reduction of peaks in power consumption, absorption or production of reactive power (when required) and improving the power quality in the studied microgrid are estimated. For this purpose a set of usual load profiles of electric vehicle charging modes are studied and presented. Simulation results demonstrate the potential of electric vehicles as a flexible load and energy storage for peak load shaving in microgrids. [ABSTRACT FROM AUTHOR]

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The intelligent building skin has multiple roles. One of them is the ability to control energy flows in the building. The concept of intelligent skin is related to its responsive performance, sometimes but not always in relation to the energy performance of the whole building, and can be compared with the biological idea of intelligence and response. This paper analyzes the role of the active facade as the part of an intelligent envelope in controlling the required amount of energy for heating. The active facade has the function to reduce the internal temperature in the rooms that have not been occupied for a long period of time and thus reduce the amount of energy required for heating the building. Energy requirements were calculated with EnergyPlus simulation software for typical residential building in Serbia. It is shown that the appropriate response of the opaque part of intelligent skin to occupancy can result in annual heating energy reduction of up to 8.8% or 3.51kWh/m²a. [ABSTRACT FROM AUTHOR]

One of the key strategies to reduce fuel consumption and emissions is given by engine downsizing, together with turbocharging. Under this aspect, the possibility to couple an electric drive to the turbocharger to recover the residual energy of the exhaust gases is becoming more and more attractive. However, additional energy coming from an electric turbo compound (ETC) application has to be managed by the vehicle powertrain through a proper energy management strategy. This study shows the numerical results of a research programme under way focused on the comparison of the benefits resulting from the application of two ETC configurations to a medium size vehicle equipped with a small four cylinders turbocharged diesel engine (1561 cm3). Starting from the experimental maps of the turbine and compressor, the complete engine model was created using a commercial one‐dimension code. The numerical activity then moved to the whole vehicle modelling. Engine results have been used to properly define a powertrain architecture and energy management strategy in order to maximise the benefits coming from the single‐ETC or the dual‐ETC solution. Finally, vehicle performance and energy flows have been analysed in different real driving conditions and compared to the original vehicle without ETC. [ABSTRACT FROM AUTHOR]

Agrarian metabolism applies the social metabolism framework to agriculture. It focuses on the study of the exchange of material and energy flows between a society and its environment for producing useful biomass. These flows must maintain the fund elements of the agroecosystem in sufficient quantity and of sufficient quality for them to continue providing ecosystem services. This methodology was applied to Spanish agriculture between 1960 and 2008, a period characterized by a deep process of intensification based on external inputs (EIs). We specifically focused on nitrogen (N), phosphorus (P), potassium (K), carbon (C) and energy flows and on the three fund elements that they sustain such as soil, biodiversity and woodland. The results show that the growing incorporation of EIs has broken the equilibrium between land and biomass uses required by traditional farming, lowering the density of internal energy loops. On cropland, the relative fall in unharvested biomass had a negative effect on both biodiversity and the soil, which reduced the replenishment of organic C between 1960 and 1990. The sharp increase in internal and external flows of biomass for animal feed hardly contributed to increasing soil organic carbon (SOC) between 1990 and 2008 because of the fact that these flows had increasingly lower C:N ratios. The massive importation of N in feed and mineral fertilizers (553 and 1150 Gg in 2000, respectively) increased the surplus and the losses of N, which in turn could have a negative impact on biodiversity, water and the atmosphere. The scenario constructed without imported animal feed would allow a reduction in the environmental impacts related to the excess of N, with hardly any negative effect on SOC replenishment and improving energy return rates in the form of total, unharvested and accumulated phytomass. [ABSTRACT FROM AUTHOR]

Multi-vector energy systems take into account synergies between different energy vectors (cooling/heat/electricity/gas), which will increase the flexibility for equalising the fluctuations from the renewable energy, and thus facilitate the penetration of renewable energy. This paper focuses on developing whole-system analysis and planning methods of energy conversion and storage devices in multi-vector energy systems, to achieve an overall optimum of energy systems. Various energy conversion and storage devices (such as photovoltaic, CHP, gas boilers, battery energy storage systems (BESS), ice storage and so forth) are planned coordinately as an integrated whole. According to the electricity demand during the planning period and the power and energy balance between supply and demand, the size of energy conversion and storage devices are determined to improve the energy efficiency and the energy supply reliability, as well as mitigate carbon emissions. [ABSTRACT FROM AUTHOR]

Nowadays, the conceptualization of circular economy is an attractive managerial tool among governments and businesses throughout the word, while ecosystem services are a contentious issue due to the particular needs of humans’ well-being. At this review the interactions between the principles of ecosystem services and the circular economy were investigated in the light of inter-organizational systems. This evaluation was based on more and more complex processes, while the integration of the growing circular economy concept within the shrinking parent ecosystem unveiled challenges and constraints for products’ end of life and quality. It was argued that: (a) The existence of social and people-related barriers can be considered under three groups, namely, the “sustainable provision and modeling schemes”, “socio-cultural appreciation and payment schemes”, and “regulatory and maintenance schemes”, (b) The impacts of circular economy—ecosystem services toward an inter-organizational functional stream model associated with distinguished proactive and post treatment risk values (c) The functionality and the accountability of the technosphere are the two critical components to support the restorative and the regenerative perspectives of the biosphere. The aforementioned findings unveiled new emerging paths to be further investigated, offering a deeper appraisal of circular economy under the inter-organizational perception.

The mechanisms for maintenance of food web structure and function in the face of frequent disturbance has been a question in ecology for many years. Local point-wise stability of theoretical food webs or robustness assessment of empirical binary food webs are the two principal techniques that have been used to address this question. However, many theoretical webs are often small, constructed randomly or from theoretical algorithms (such as Cascade or Niche models), and assume Lotka-Volterra dynamics. Whilst the binary webs used also assume all interactions are equal and that webs are donor controlled. Recent dynamic stability analysis of empirical quantitative webs has sought to improve this assessment. Here we investigate how aquatic food web structure and the direction of trophic cascades interact to affect the robustness of total carbon flow between species after a disturbance. The robustness of the 18 food webs is higher if predator control dominates. Webs with predator control were however stabilised by weak indirect interactions and short food chains. [ABSTRACT FROM AUTHOR]