A common understanding of sustainable production principles and the identification of sustainable manufacturing practices among practitioners are key starting points in studying how manufacturers are making their operations more sustainable. However, there is a lack of insight in the literature connecting conceptual sustainable production principles, and the practices reflecting these principles. Using semi-structured interviews founded on the sustainable production principles posed by the Lowell Center for Sustainable Production, this paper presents an outlook of how companies in different industries carry out manufacturing practices related to the sustainability production principles. Results showed that the majority of sustainable manufacturing practices remain strongly centered on the environmental dimension of sustainability, with the greatest number of practices emanating from principles concerning energy and material conservation, and waste management. Similarly, reactive sustainable manufacturing practices prevailed over proactive sustainable manufacturing practices, as most of the practices aimed to comply with regulatory and market pressures. Quality and environmental management systems were acknowledged as important tools for putting sustainable production principles into practice; while Swedish environmental and social regulations were found to drive sustainable manufacturing practices. This study connects sustainable production principles with sustainable manufacturing practices and opens the way for further studies on a global or sector-specific scale.
This article aims to support the targeted worldwide green transition process by introducing and thoroughly analyzing a low-temperature heating and high-temperature cooling, smart building system. This concept allows for greater use of renewable energy while utilizing less input energy than conventional heating and cooling techniques. The proposed system consists of a reversible water-to-water heat pump driven by low-temperature geothermal energy. A rule-based control strategy is developed to establish an intelligent connection with the regional energy grids for peak shaving and compensating for the building's energy costs over the year. The dynamic simulation is carried out for a multi-family building complex in Stockholm, Sweden, using TRNSYS. The most favorable operating condition is determined via an artificial neural network-assisted tri-objective optimizer based on the grey wolf algorithm in MATLAB. The comparison of the proposed smart model with the conventional system in Sweden results in 332%, 203%, and 190% primary energy reduction, cost saving, and carbon dioxide emission mitigation, respectively. As indicated by the parametric results, the conflicting fluctuation between desirable and unfavorable indicators highlights the importance of multi-objective optimization. The grey wolf optimizer obtains 12% higher efficiency, 1.2 MWh lower annual bought energy, 24 $/MWh lower unit cost, and 5.1 MWh more yearly sold energy than the design condition. The scattered distribution reveals that tank volume and subcooling degree are sensitive parameters. According to the transient results, the suggested smart system can independently satisfy the building's heating, cooling, and electricity demands for more than 81% of the year, thanks to the two-way connection with the electricity and heating networks via the rule-based controller.
Existing schemes of solid waste handling have been improved implementing advanced systems for recovery and reuse of various materials. Nowadays, the 'zero waste' concept is becoming more topical through the reduction of disposed waste. Recovery of metals, nutrients and other materials that can be returned to the material cycles still remain as a challenge for future. Landfill mining (LFM) is one of the approaches that can deal with former dumpsites, and derived materials may become important for circular economy within the concept 'beyond the zero waste'. Perspectives of material recovery can include recycling of critical industrial metals, including rare earth elements (REEs). The LFM projects performed in the Baltic Region along with a conventional source separation of iron-scrap, plastics etc. have shown that the potential of fine-grained fractions (including clay and colloidal matter) of excavated waste have considerably large amounts of potentially valuable metals and distinct REEs. In this paper analytical screening studies are discussed extending the understanding of element content in fine fraction of waste derived from excavated, separated and screened waste in a perspective of circular economy. Technological feasibility was evaluated by using modified sequential extraction technique where easy extractable amount of metals can be estimated. Results revealed that considerable concentrations of Mn (418-823 mg/kg), Ni (41-84 mg/kg), Co (10.7-19.3 mg/kg) and Cd (1.0-3.0 mg/kg) were detected in fine fraction (<10 mm) of waste sampled from Hogbytorp landfill, while Cr (49-518 mg/kg) and Pb (30-264 mg/kg) were found in fine fraction (<10 mm) of waste from Torma landfill revealing wide heterogeneity of tested samples. Waste should become a utilizable resource closing the loop of anthropogenic material cycle as the hidden potential of valuable materials in dumps is considerable.
Agrivoltaic systems represent a key technology for reaching sustainable development goals, by reducing the competition of land used for food versus land used for electricity. Moreover, agrivoltaic systems are at the centre of the nexus between electricity production, crop production, and irrigation water savings. In this study, an optimisation model for vertically mounted agrivoltaic systems with bifacial photovoltaic modules is developed. The model combines three main sub-models: solar radiation and shadings, photovoltaics, and crop yield. Validation of the sub-models is performed showing good agreement with measured data and commercial software. The optimisation model is set as multi objective to explore the trade-offs between competing agrivoltaic key performance indicators. Oats and potatoes are used as reference crops in this study. The results show that the row distance between bifacial photovoltaic module structures significantly affects the photosynthetically active radiation distribution. The resulting crop yield of oats and potato is reduced by about 50% as row distance decreases from 20 m to 5 m. The implementation of an agrivoltaic system for the investigated crops at the chosen location shows a land equivalent ratio above 1.2, which justifies the use of the technology for reaching national sustainability goals.
Agrivoltaic systems, which allow the coexistence of crop and electricity production on the same land, are an integrated water–energy–food nexus solution that allows the simultaneous attainment of conflicting Sustainable Development Goals. This study aims to analyse experimental results on the responses of ley grass yield and quality to shadings in the first agrivoltaic system in Sweden. It also aims to validate an integrated modelling platform for assessing agrivoltaic systems' performances before installation. An economic analysis is carried out to compare the profitability of agrivoltaic versus conventional ground-mounted photovoltaic systems and, using a Monte Carlo Analysis, to identify the parameters that most affect the profitability. Despite the agrivoltaic systems’ supporting structures and photovoltaic modules producing an average ∼25% reduction in photosynthetically active radiation at ground level, no statistically significant difference was observed between the yield of the samples under the agrivoltaic system compared to the yield of the samples in the reference area. The agrivoltaic system attained land equivalent ratios of 1.27 and 1.39 in 2021 and 2022, respectively. The validation results of the integrated modelling platform show that the sub-model concerning the crop yield response to shading conditions tends to underestimate ∼7% the actual average crop yield under the agrivoltaic system. The results of the economic analysis show that, from a net present value perspective, agrivoltaic systems have a profitability that is ∼30 times higher than a conventional crop rotation in Sweden.
Using a multi-disciplinary approach, this paper integrated spatial analysis with agricultural and energy system modelling to assess the impacts of drought on crop water demand, water availability, crop yield, and electricity requirements for irrigation. This was done by a novel spatially-explicit and integrated water-food-energy nexus model, using the spatial climatic data generated by the mesoscale MESAN and STRANG models. In this study, the model was applied to quantify the effects of drought on the Swedish irrigation sector in 2013, a typical drought year, for a specific crop. The results show that drought can severely affect the crop yield if irrigation is not applied, with a peak yield reduction of 18 t/ha, about 50 % loss as compared to the potential yield in irrigated conditions. Accordingly, the water and energy requirements for irrigation to halt the negative drought effects and maintain high yields are significant, with the peaks up to 350 mm and 700 kWh per hectare. The developed model can be used to provide near real-time guidelines for a comprehensive drought management system. The model also has significant potentials for applications in precision agriculture, especially using high-resolution satellite data.
A reduction of demand for electrical power in peak periods, commonly called peak shaving, is beneficial for customers from the economic point of view. However, it is also of considerable importance for the National Power System operation in terms of grid stability. This research focuses on the issue of nationwide potential of peak shaving by PV installations in office buildings in Poland. It is assumed that this sector can play a significant role in decreasing the demand for peak power on a large scale. The modelling of office building load was conducted with the use of an Artificial Neural Network. The study took into consideration different tilt and orientation configurations of PV modules as well as their degradation. The impact of peak shaving on the National Power System was assessed on the basis of the monthly peak load balancing factor. The influence of PV installations on grid infrastructure was estimated based on changes in transformer lifetime. The research showed that the optimum PV capacity for an average office building was approximately 600-800 kW(p) with a south orientation and tilt angle of 30 degrees. The highest peak shaving capacity on the country level is observed for PV systems with a south-east orientation. 273.75 MWp in PV capacity reduces the maximum national load by 200 MW in May. The analysed PV system producing electricity for self-consumption, can prolong the lifetime of the overloaded transformer connected to the office building by up to 36%.
Energy transitions are ongoing processes all over the world. While sustainable solutions are envisioned for the future, many societies are still under high-carbon and high-pollution energy regime borne by fossil fuels. How to design pathways towards sustainable energy transition has attracted worldwide concerns. Understanding the possible transition pathways of the energy system requires the integration of new energy technologies, environmental sciences, economics and management. This Special Issue of Journal of Cleaner Production targets to collect the latest research results on sustainable energy systems, discover innovative avenues and inspiring models and share knowledge on energy system modelling and management. In this paper, we identify 4 themes on sustainable energy transition pathways including: (1)Sustainable energy economics and management; (2)Renewable energy generation and consumption; (3)Environmental impacts of energy systems; and (4)Electric vehicle and energy storage. Theories, technologies, innovative models, and successful experiences are discussed accordingly. It is suggested that creative, robust and audacious strategies in governance, management and education are needed to boost sustainable energy transition across various scales and sectors.
Providing the energy needs of the cumulatively increasing population has become a challenge for the regional energy systems in the world. The most critical challenge is to supply enough energy in the forms of heat and power during the cold and warm periods of the year with the lowest production cost and minimum environmental impacts. A solution is to increase the green energy supply from renewable energy resources such as solar, wind power, and hydropower. In order to apply this solution in the real energy system, potentials for clean energy supply in an optimized manner should be evaluated. In this study, an optimization model is developed for a regional energy system in the central part of Sweden. The studied system consists of Combined Heat and Power (CHP)plants and heat water boilers together with renewable energy supply from rooftop Photo Voltaic (PV)- solar collectors and regional hydropower plants. The General Algebraic Modeling System (GAMS)is used to create the model based on the Mixed Integer Linear Programming (MILP)method. The goal is to evaluate the influence of local renewable energy systems on the production planning of CHP plants in a region. Two different scenarios are investigated based on the extremes in energy supply and demand concerning the increased use of Electrical Vehicles (EVs)and more application of Heat Pumps (HPs)in the system. The results show that installation of rooftop PV systems has the potential to reduce the electricity import to the region; however, it will at the same time reduce the operation time of the CHP plans during the summer period. With increased use of HPs for heating, the shut off time for CHP plants is further increased. Increase in electric passenger cars penetration in the system has no impacts on the production profiles of the plants. The regional electricity demand grows significantly by more utilization of EVs and increased application of heat pumps in the studied system. The high electricity demand will mainly be satisfied by importing electricity from outside the region together with low production from CHP plants and the power generated by the rooftop PV systems and regional hydropower. The developed optimization model with studied scenarios can be applied to other energy systems to increase the knowledge of production planning and feasibility of a fossil fuel free energy system.
This paper evaluates the effects on profitability of biofuel production if biofuel producers would sell the waste heat from the production to a local district heating system. All analyses have been performed considering four different technology cases for biofuel production. Two technology cases include ethanol production which is followed by by-production of raw biogas. This biogas can be upgraded and sold as biofuel (the first technology case) or directly used for combined heat and power production (the second technology case). The third and the fourth technology cases are Fischer-Tropsch diesel and dimethyl ether production plants based on biomass gasification. Two different district heating price levels and two different future energy market scenarios were considered. The sensitivity analyses of the discount rate were performed as well. In the case of energy market conditions, the profitability depends above all on the price ratio between biomass (used as the feedstock for biofuel production) and crude oil (used as the feedstock for fossil diesel and gasoline production). The reason for this is that the gate biofuel prices (the prices on which the biofuel would be sold) were calculated assuming that the final prices at the filling stations are the same as the prices of the replaced fossil fuel. The price ratios between biomass and district heating, and between biomass and electricity, also have an influence on the profitability, since higher district heating and electricity prices lead to higher revenues from the heat/electricity by-produced. Due to high biofuel (ethanol + biogas) efficiency, the ethanol production plant which produces upgraded biogas has the lowest biofuel production costs. Those costs would be lower than the biofuel gate prices even if the support for transportation fuel produced from renewable energy sources were not included. If the raw biogas that is by-produced would instead be used directly for combined heat and power production, the revenues from the electricity and heat would increase, but at the same time the biofuel efficiency would be lower, which would lead to higher production costs. On the other hand, due to the fact that it has the highest heat efficiency compared to the other technologies, the ethanol production in this plant shows a high sensitivity to the district heating price level, and the economic benefit from introducing such a plant into a district heating system is most obvious. Assuming a low discount rate (6%), the introduction of such a plant into a district heating system would lead to between 28% and 52% (depending on the district heating price level and energy market scenario) lower biofuel production costs. Due to the lower revenues from the heat and electricity co-produced, and higher capital investments compared to the ethanol production plants, Fischer-Tropsch diesel and dimethyl ether productions are shown to be profitable only if high support for transportation fuel produced from renewable energy sources is included. The results also show that an increase of the discount rate from 6% to 10% does not have a significant influence on the biofuel production costs. Depending on the biofuel production plant, and on the energy market and district heating conditions, when the discount rate increases from 6% to 10%, the biofuel production costs increase within a range from 2.2% to 6.8%.
Biofuel production through polygeneration with heat as one of the by-products implies a possibility for cooperation between transport and district heating sectors by introducing large-scale biofuel production into district heating systems. The cooperation may have effects on both the biofuel production costs and the district heating production costs. This paper is the second part of the study that investigates those effects. The biofuel production costs evaluation, considering heat and electricity as by-products, was performed in the first part of the study. In this second part of the study, an evaluation of how such cooperation would influence the district heating production costs using Stockholm's district heating system as a case study was performed. The plants introduced in the district heating system were chosen depending on the future development of the transport sector. In order to perform sensitivity analyses of different energy market conditions, two energy market scenarios were applied. Despite the higher revenues from the sale of by-products, due to the capital intense investments required, the introduction of large-scale biofuel production into the district heating system does not guarantee economic benefits. Profitability is highly dependent on the types of biofuel production plants and energy market scenarios. The results show that large-scale biogas and ethanol production may lead to a significant reduction in the district heating production costs in both energy market scenarios, especially if support for transportation fuel produced from renewable energy sources is included. If the total biomass capacity of the biofuel production plants introduced into the district heating system is 900 MW, the district heating production costs would be negative and the whole public transport sector and more than 50% of the private cars in the region could be run on the ethanol and biogas produced. The profitability is shown to be lower if the raw biogas that is by-produced in the biofuel production plants is used for combined and power production instead of being sold as transportation fuel; however, this strategy may still result in profitability if the support for transportation fuel produced from renewable energy sources is included. Investments in Fischer-Tropsch diesel and dimethyl ether production are competitive to the investments in combined and power production only if high support for transportation fuel produced from renewable energy sources is included.
In this study, cooperation between Stockholm's transport and district heating sectors is analysed. The cooperation concerns the integration of biofuel polygeneration production. A MODEST optimisation model framework is used, assuming various energy market and transport sector scenarios for the year 2030. The scenarios with biofuel production and increased biofuel use in the region are compared with reference scenarios where all new plants introduced into the district heating sector are combined heat and power plants, and the share of biofuel used in the transport sector is the same as today. The results show that the cooperation implies an opportunity to reduce fossil fuel consumption in the sectors by between 20% and 65%, depending on energy market conditions and assumed transport sector scenarios. If we consider biomass an unlimited resource, the potential for greenhouse gas emissions reduction is significant. However, considering that biomass is a limited resource, the increase of biomass use in the district heating system may lead to a decrease of biomass use in other energy systems. The potential for reduction of global greenhouse gas emissions is thus highly dependent on the alternative use of biomass. If this alternative is used for co-firing in coal condensing power plants, biomass use in combined heat and power plants would be more desirable than biofuel production through polygeneration. On the other hand, if this alternative is used for traditional biofuel production (without co-production of heat and electricity), the benefits of biofuel production through polygeneration from a greenhouse gas emissions perspective is superior. However, if carbon capture and storage technology is applied on the biofuel polygeneration plants, the introduction of large-scale biofuel production into the district heating system would result in a reduction of global greenhouse gas emissions independent of the assumed alternative use of biomass.
Selective noncatalytic reduction (SNCR) systems have been widely used for denitrification in small capacity boilers, such as biomass- and waste-fueled boilers. However, these systems cannot meet the requirements of ultralow emission regulations, i.e., 50 mg m−3. This work proposes a new solution that combines SNCR and activated carbon (AC). To solve the problem caused by the wettability of AC, which can significantly reduce the quantity of NOx that can be adsorbed and block active cites, hydrophobic modification was employed to amend the properties of AC. The influences of the key operating parameters on the denitrification of AC, including the reaction temperature, O2 concentration, feed gas flow rate, and contents of SO2 and CO2, have been investigated experimentally. A novel solution that combines AC and SNCR was proposed for industrial applications, and the economic feasibility has been verified. The results have demonstrated that this hybrid solution can achieve a low levelized cost of denitrification, which is 59.8% and 33.7% lower than those of SCR and hybrid SNCR/SCR.
The Environmental technology (ET) sector delivers environmentally preferably products. Little is known about whether companies in the ET sector set environmental objectives relating to their own production processes. This paper presents results from an online survey on environmental work in enterprises listed by the Swedish Environmental Technology Council (Swentec). The survey found that depending on the specific subsector, only between 21% and 45% of companies provide information about their environmental work on their website. This paper proposes environmental aspects of production and products as bases for corporate greening and for de fining‘green’and‘green-green’business and identifies three main motivations for the companies within ET sector to operate as ‘green-green’businesses:‘competitiveadvantage’, ‘environmental responsibility’ and ‘environmental leadership’.
This paper compares and contrasts the lean product development (LPD) and green product development (GPD) concepts through a systematic literature review including 102 journal publications. The review resulted in 14 findings that were organised according to four dimensions: general, process, people and tools/techniques. A number of similarities between the concepts were found. For example, implementation of both concepts calls for a systems perspective where the dimensions of process-people- tools/techniques are linked holistically. Differences between the LPD and GPD concepts lie in: their goal and focus, value construct, process structure, performance metrics, and tools/techniques used. The findings do not unambiguously support that "green thinking is thinking lean" and consequently it cannot be argued that LPD and GPD are two sides of the same coin, meaning that LPD automatically leads to greener products or that GPD ensures improvements and efficiency in the product development process. However, it is reasonable to conclude that LPD and GPD belong to the same "currency". That is, the concepts share a number of similarities that indicate a synergistic relationship. This synergistic relationship has been accentuated by a nine propositions where the potential for cross-field learning is shown.
The process of decarbonising economies has to take place on multiple levels. One of the objectives is to ensure renewables-based energy self-sufficiency of cities. Cities have become home to the majority of the world's population, and at the same time contribute enormously to environmental pollution. Considering the above, the purposes of this paper are threefold: to formulate a methodology for estimating rooftop photovoltaics (PV) potential in urban areas based on detailed Light Detection And Ranging (LiDAR) data; to calculate the spatial variability of load and photovoltaics energy supply, and thus to distinguish zones with various levels of energy self-sufficiency; and finally, to scrutinise the economic and environmental aspects of such a solution in given conditions. Wroclaw, the capital city of the Lower Silesia voivodeship in south-west Poland (Central Europe), was selected as a case study. The city has a population of close to 650,000 and an annual electricity consumption slightly exceeding 2.2 TWh. Industry constitutes 46% of that demand, and households 31%. The results show that up to 850 MW p of rooftop PV can be installed in the city, which has the potential to reduce the electrical energy related emissions by almost 30% and simultaneously to increase the city's energy self-sufficiency. Although energy storage, in the form of batteries, slightly improves both the autarky and environmental indices, the relation between potential PV generation and load makes them very infrequently useful (mostly in summer) and not economically justified.
Innovative, resource-efficient solutions and effective waste management systems capture value in business and contribute to sustainability. However, due to scattered waste management responsibilities in the vehicle industry and the orientation of operations management and lean tools, which mostly focus on lead-time and labour-time improvements, the requirement of a collaborative method to include material waste efficiency in operational development is identified. The main purpose of this research is to study how operations management and environmental management can be integrated on an operational level and include the waste management supply chain. Based on a literature review of environmental and operational improvement tools and principles, the gaps and needs in current practice were identified. A large case study implementing a waste flow mapping (WFM) method on a set of manufacturing sites revealed potentials in terms of reducing material losses and inefficiencies in the handling of materials and waste. Finally, the integrated WFM method was analysed with respect to the gaps and needs identified in the existing body of tools for operational and environmental improvement. The method combines lean manufacturing tools, such as value stream mapping with cleaner production and material flow cost accounting strategies. The empirical data showed that the WFM method is adequate for current state analysis of waste material efficiency potentials, especially when multiple organisations are involved. However, further development and specific methods are needed such as, for example, logistics inefficiencies, root cause analysis, implementation guidelines for best practice and systems for performance monitoring of actors.
This paper focuses on integration of operations management, specifically production system models with environmental management and related issues such as quality and safety. Based on knowledge concerning lean-based improvement programmes for company-specific production systems (XPS) and integration between formal management systems, such as ISO 9001 and 14001, industrial practices from integrating management systems with the XPS were studied. A literature-based comparison between formal management systems and XPS is made, indicating integration potentials. The empirical research is an analysis of five vehicle and automotive companies in which various efforts have been made to integrate their management systems with their XPS. The results show that although conscious steps have been taken since the introduction of ISO 14001 in integrating environmental management into everyday operations, there are still obstacles to overcome. To fully include sustainability aspects, the characteristics of the improvement systems have to be adapted and extended. One barrier to extended integration is the lack of integration strategy. There is further a lack of sustainability metrics and adaptation of improvement methods to push companies' operational performance. In addition, organisational issues still arise concerning the responsibility and ownership of environmental management in relation to operations. Based on these results it is concluded that processes for integration are recommended; however, each organisation needs to consider its operations, corporate culture and business opportunities of its environmental management. Still, incorporating environmental management systems into XPS is seen as an effective way of establishing company commonality in continuous improvement, resulting in holistic understanding and improved organisation performance.
The traditional carbon accounting method, with a lag of over 2 years due to the release time of statistical yearbooks, impedes timely policy adjustments in urban planning and management. Hence, there is an urgent need to establish a real-time carbon emissions characterization model. Xi'an which has a complex land-use structure was chosen as the study site and its carbon emissions were calculated using the Emission Factor Method. The GIS-Kernel Density (KD) model was constructed, and land use was subdivided based on Point of Interest (POI) and road network data. Based on the results of carbon emissions accounting and land-use subdivision, a Multilayer perceptron (MLP) model was established. The remote sensing (RS) images of Xi'an underwent supervised classification, and the carbon emissions of Xi'an were characterized based on the subdivision results and MLP model. The results show that: (1) The accuracy of the characterization model is more than 90%, and with the improvement of RS technology, the accuracy will be further improved; (2) Compared with the existing model, this model can real time reflect the spatial distribution of carbon emissions; (3) Atmospheric emission of Xi'an will be 41.92 million tons at the end of 2022, a decrease of 2.80 million tons compared with that of 2020, but an increase of 0.33 million tons from 2021. The north of Xi'an and periphery of the central urban area are the main carbon sink loss areas, while the east of Xi'an and north foot of the Qinling Mountains are carbon sink growth areas.
Renewable energy is well recognized not only as resource that helps to protect the environment for future generations but also as a driver for development. Waste-to-energy systems can provide renewable energy and also improve sustainability in waste management. This article contributes a case study of stepwise reconfiguration of the waste management system in a developing country to the literature of transitions. The conditions for a systemic transition that integrates large-scale biogas generation into the waste management system have been analyzed. The method included a multi-criteria evaluation of three development steps for biogas, an economic analysis, and an institutional and organizational analysis. The results revealed economic as well as institutional and organizational barriers. Clearly, public and private sectors need to engage in sustainability. There is also a lack of pressure – mainly because of fossil fuel subsidies – that prevents a transition and creates a lock-in effect. To break the lock-in effect the municipality's institutional capacity should be strengthened. It is possible to strengthen biogas economically by integrated waste management services and sales of biofertilizer. A stepwise reconfiguration would be initiated by adopting technologies that are already established in many developed countries but are novelties in a Bolivian context – as a response to sustainability challenges related to waste management. The article focuses on the main challenges and the potential for biogas technology in Bolivia and a pathway towards a new, more sustainable system is suggested.
Research on the effect of income inequality on pollution shows mixed results. This paper takes a new look at the urban air pollution data set of the U.N.'s Global Environmental Monitoring System (GEMS). We investigate the impact of income inequality on urban air pollution and relate the results to a median-voter model. In this model, more income inequality decreases the median income, reduces pollution controls, and increases output and pollution when the median income is above a threshold. We find that income inequality, measured by the Gini coefficient, increases SO2 concentration in the rich democracies. The estimated effects are non-negligible in size. For the poor non-democracies, we find no evidence that the Gini coefficient impacts SO2 concentration. The Gini coefficient is estimated to increase the smoke concentration at the five- or ten-percent significance level in most specifications in a pooled sample. We find no evidence that the Gini coefficient impacts the concentration of particulates in a pooled sample. We conclude that the empirical results largely are consistent with the medianvoter model.
Although energy conservation and reduction in environmental impact are on the international and most national agendas, service firms rarely include energy consumption metrics in their strategic decision-making. One reason for the omission is that for service industries, firm level energy utilization is most commonly measured in kilowatt hours per square meter of office space where changes often related to the space rather than the firm performance. The measure also presents several problems for firms in service industries. First, energy conservation and reduction may be counterproductive for service firms that are growing and require energy to sustain that growth. Second, it may not relate to national and international goals which are often focused on the amount of carbon dioxide produced generating energy than the total amount of energy consumed. Third, it treats energy as a utility rather than a resource in firms’ value creation. Results from a field study focused on service firms in Sweden suggests that focusing on energy productivity overcomes the limitations of existing measures and produces positive results. By conceptualizing energy productivity as output per unit of energy, we create a conservation metric that enables service firms to measure their contributions to energy consumption relative to national economic growth. As a result, energy productivity aligns the interests of service organizations with those of policy makers and conservationists.
A major factor in the continued deterioration of the global environment is unsustainable management of resources that includes the type and quantity of resources consumed and manufactured as well as the subsequent generation and treatment of wasted materials. Improved material efficiency (ME) in manufacturing is key to reducing resource consumption levels and improving waste management initiatives. However, ME must be measured, and related goals must be broken down into performance indicators for manufacturing companies. This paper aims to improve ME in manufacturing using a structured model for ME performance measurements. We present a set of ME key performance indicators (ME-KPIs) at the individual company and lower operational levels based on empirical studies and a structured literature review. Our empirical findings are based on data collected on the performance indicators and material and waste flows of nine manufacturing companies located in Sweden. The proposed model categorizes ME-KPIs into the following categories: productive input materials, auxiliary input materials, output products, and residual output materials. These categories must be measured equally to facilitate the measurement, assessment, improvement and reporting of material consumption and waste generation in a manufacturing context. Required qualities for ME-KPI suggested in literature are also discussed, and missing indicators are identified. Most of the identified ME-KPIs measure quality- and cost-related factors, while end-of-life scenarios, waste segregation and the environmental effects of waste generation and material consumption are not equally measured. Additionally, ME-KPIs must also be connected to pre-determined goals and that defining or revising ME-KPIs requires communication with various external and internal actors to increase employees’ awareness and engagement.
Improved material efficiency is a key to improve the circular economy and capturing value in industry. Material efficiency reduces the generation of industrial waste, the extraction and consumption of resources, and energy demands and carbon emissions. However, material efficiency in the manufacturing sector, as a means of improving the recyclability, reusability, reduction and prevention of industrial waste, is little understood. This study aims to investigate, on a micro-level, further material efficiency improvement opportunities, barriers and strategies in selected manufacturing companies in Sweden, focusing on increasing waste segregation into high quality circulated raw material. Improvement opportunities at large global manufacturing companies are investigated; barriers hindering material efficiency improvement are identified and categorized at two levels; and strategies that have been deployed at manufacturing companies are reviewed. Empirical findings reveal (1) further potential for improving material efficiency through higher segregation of residual material from mixed and low quality fractions (on average, 26% of the content of combustible waste, in weight, was plastics; 8% and 6% were paper and cardboard, respectively); (2) the most influential barriers are within budgetary, information, management, employee, engineering, and communication clusters; (3) a lack of actual material efficiency strategy implementation in the manufacturing companies. According to our analysis, the majority of barriers are internal and originate within the manufacturing companies, therefore they can be managed (and eradicated if possible) with sufficient resources in terms of man hours, education and investment, better operational and environmental (waste) management, better internal communication and information sharing, and deployment of material efficiency strategies.
Suburban railway systems are recognized as one of the most promising options to improve the environmental footprint of urban passenger transport in developing countries. In the present study, life cycle assessment has been performed for the Mumbai Suburban Railway with the objective of developing a comprehensive methodology for environmental evaluation of suburban railway projects in terms of energy consumption and relevant impact categories. The system boundary comprises the construction and maintenance of railway infrastructure such as tracks, power supply installations, foot over bridges and platforms, in addition to manufacturing, maintenance and operation phase of Electric Multiple Unit (EMU). The functional unit identified for this study is per Passenger Kilometer Travelled within a service lifetime of EMU of 25 years. The results show that operation phase is the main contributor (87-94%) to the total environmental impact, whereas the contribution of remaining life cycle phases is relatively insignificant (6-13%). It is mainly due to electricity production from non-renewable sources in India. The material and energy intensive rails entail the major contribution to construction phase (24-57%) and maintenance phase (46-71%), whereas the contribution from fastenings, ballast and on-site energy consumption is less significant. The increasing utilization of renewable energy, lightweighting of coach bodies, enhancing the service life and reuse potential of rails and fastenings and enhancing train occupancy are fundamental to accomplish suburban railways as a clean transportation mode. This comprehensive study can serve as a preeminent support and benchmark for the future environmental performance assessments of public transportation in India. Eventually, decision makers and regional transport planners can more effectively craft the strategic decisions and priorities of measures for providing sustainable mobility options.
Sweden faces several challenges with more intermittent power in the energy system. One challenge is to have enough power available in periods with low intermittent production. A solution could be to reduce peak demand and at the same time produce more electricity during these hours. One way of doing this is to convert electricity-based heating in buildings to district heating based on combined heat and power. The study analyzes how much a Swedish municipality can contribute to lowering peak electricity demand. This is done by quantifying the potential to reduce the peak demand for six different scenarios of the future heat demand and heat market shares regarding two different energy carriers: electricity-based heating and district heating. The main finding is that there is a huge potential to decrease peak power demand by the choice of energy carrier for the buildingsâ heating system. In order to lower electricity peak demand in the future, the choice of heating system is more important than reducing the heat demand itself. For the scenario with a large share of district heating, it is possible to cover the electricity peak demand in the municipality by using combined heat and power.
Industrial energy programs such as energy audit programs and long-term agreements (LTAs) are one of the most common means of promoting energy efficiency in industry. As a result of the European Energy End-Use Efficiency and Energy Services Directive from 2006, the Swedish Government Bill proposed a national energy program towards industrial small- and medium-sized enterprises (SMEs) using more than 500 MWh energy annually. The aim of this paper is to present the structure and design of the program, adopted in 2010, the logics in brief behind the structure, as well as an ex-ante evaluation of the program's cost-effectiveness. The paper is aimed towards the part of the program involving industry, i.e. not the part involving companies within service and sales etc. The proposed design primarily includes a subsidized energy audit with some minor LTA-elements, such as the need to report results from the energy audit, to present a plan over which measures to conduct, and after three years present which measures that were implemented. The ex-ante evaluation of the program shows a cost-effectiveness of 0.25-0.50 Eurocents/kWh, yielding savings of about 700-1 400 GWh annually.
The utilization of geothermal energy is becoming increasingly important in the current transition towards sustainable energy sources. Among the various methods of utilizing geothermal energy, the use of hybrid geothermal power plants that exploit CO2 fluid for preheating in electricity generation has been identified as an attractive approach. Additionally, the shallow ground source heat pump (SGSHP) has been proven to be superior in previous experimental studies. However, the full-scale utilization of geothermal energy, through generating electricity from geothermal power plants and applying waste heat with SGSHPs for auxiliary heating, needs further exploration. This study proposes a novel CO2 hybrid geothermal system that incorporates a GSHP heating system. The hybrid geothermal system uses CO2 as the underground working fluid, and the electricity and waste heat are used to assist the GSHP for heating, ventilation, and air conditioning. The proposed system can produce 11.41 MW of electricity, 80 °C of hot water, and 34.76 MW of cold energy by driving 50 MW of the geothermal heat. Through a comprehensive analysis of the economy, energy, exergy, and environment, the results demonstrate that the maximum exergy damage of the refrigeration power cycle is 37999.33 kW, which has the highest exergy losses. The exergy loss of the steam turbine heat power conversion in the geothermal power generation process is the highest, but this loss can be effectively reduced through heat integration. The optimal cooling temperature of the coupled system should be set at 8 °C, and it has a good investment prospect. In summary, the CO2 hybrid geothermal system can realize effective cogeneration and fully utilize geothermal energy. Therefore, it has great potential to contribute to the transition towards a sustainable energy future.
The developments in electric vehicles (EVs) are driven by the need for cleaner and more efficient road transport, but vehicle charging poses significant challenges to the electric grid and electricity sector planning. These challenges are further amplified in the case of a highly urbanised and densely populated small island state, like Singapore, with limited space and options for electricity sector planning. In response, this study aims to evaluate the impacts of a large-scale EV deployment on the electricity sector from a whole-system perspective with focus on investments in the power sector for EV adoption, assuming minimum deployment of advanced “smart-grid” and “vehicle-to-grid” technologies. Findings suggest that a small-scale deployment of EVs below 20% replacement can be economically manageable. A large-scale of deployment of EVs would inevitably bring a notable impact to the electricity sector regardless the state of advanced technology development. From the perspective of integrated planning, cities, especially those with high vehicle density, should continue to exercise caution with EV deployment. A large-scale deployment should be pursued after a “stress-test” of the power system infrastructure from both the technical and economic perspectives.
The integration of CO2 capture with biomass-fired power plants has attracted much attention due to its ability to achieve negative emissions. Waste-fired combined heat and power (CHP) plants with CO2 capture, on the other hand, has received little attention, and their potential remains unclear. This study aims to identify the possible range of the amount of captured CO2 and investigate the impact of CO2 capture on the performance of waste-fired CHP plants. Since heat is the primary product of CHP plants, it is important to maintain heat production unchanged when CO2 capture is integrated. Based on this prerequisite, two operating strategies (OS) were investigated, which correspond to the upper and lower boundaries of CO2 capture: OS1 was to maximize the amount of captured CO2 while keeping the heat supplied to the district heating (DH) network unchanged; and OS2 was to maximize CO2 capture while keeping both supplied heat and generated electricity unchanged. To obtain more accurate results regarding the CO2 capture, a dynamic model developed in Aspen Hysys™ was utilized to simulate monoethanolamine (MEA) based chemical absorption for CO2 capture. By using real dynamic data from a waste-fired CHP plant, dynamic simulation results showed that the highest amount of captured CO2, which was achieved in OS1, was 401 kton/year, corresponding to a CO2 capture ratio of 82%; while the lowest amount of captured CO2, which was achieved in OS2, was 99 kton/year, corresponding to a CO2 capture ratio of 20%. For OS1, the electricity generation was substantially decreased by 61%. When determining the negative emission, the emission resulted from the share of fossil fuel in the waste needs to be excluded. For the studied CHP plant, the fossil share was around 45%. As a result, only OS1 can achieve the negative emission, which was 181 kton/year; while OS2 still led to positive emissions. Compared to the plant without CO2 capture, the carbon intensity of heat was reduced from 0.405 ton/MWh to 0.091 ton/MWh in OS1 and 0.351 ton/MWh in OS2, while the carbon intensity of electricity was reduced from 0.409 ton/MWh to 0.072 ton/MWh in OS1 and 0.343 ton/MWh in OS2.
According to the recent IPCC reports, the effects from anthropogenic climate change effects are becoming more serious and actions more urgent. The global mean concentration of CO2, the most important Greenhouse Gas (GHG), in the atmosphere is now close to 400 ppm. The most comprehensive research efforts concerning safe levels propose that we should strive to keep the atmospheric concentration of CO2below 350 ppm. This is also a more transparent global goal than using effects in the components of the climate system. Most scenarios show that the combustion of fossil fuels will increase in the future, while the development of renewables is still too marginal to stop this growth. The possibility that countries will leave fossil resources underground does not seem realistic. The only options in the short run to halt emissions of CO2 are the large-scale application of Carbon Capture and Storage (CCS) in combination with increased energy efficiency. In the long run, we have to radically transform our societal metabolism towards greater resource efficiency, where renewables can play a more important role. The main barriers for implementation of CCS on a large scale are not technical, but economic and social. As long as the costs for emitting CO2 are much lower than implementing CCS technology, there will not be a market-driven development of CCS. A major challenge for CCS will be to achieve wide public acceptance, since this will also affect the future political attitude to it. This will require an open communication about safety aspects early in the planning phase, where it can be shown that safety issues can be handled, even in the event of major leaks of CO2. To assume a low probability of accidents is not a feasible way forward in the communication process. The future concerning CO2 emissions will be determined very much by actions of the biggest emitters. The developed countries have already emitted a large amount of CO2 and must now take a step forward to show that they are willing to invest in CCS technology. At this stage, it is reasonable to expect developed countries to take a leading role in developing the CCS technology on a large-scale. It is highly probable that developing countries like China will follow this path in the near future, since they have a clear ambition to take a lead in climate change mitigation in the long run and to avoid blame for a deteriorating environment.
Coal is the dominant fuel for electricity generation around the world. This type of electricity generation uses large amounts of water, increasing pressure on water resources. This calls for an in-depth investigation in the water-energy nexus of coal-fired electricity generation. In China, coal-fired power plants play an important role in the energy supply. Here we assessed water consumption of coal-fired power plants (CPPs) in China using four cooling technologies: closed-cycle cooling, once-through cooling, air cooling, and seawater cooling. The results show that water consumption of CPPs was 3.5 km(3), accounting for 11% of total industrial water consumption in China. Eighty-four percent of this water consumption was from plants with closed-cycle cooling. China's average water intensity of CPPs was 1.15 l/kWh, while the intensity for closed-cycle cooling was 3-10 times higher than that for other cooling technologies. About 75% of water consumption of CPPs was from regions with absolute or chronic water scarcity. The results imply that the development of CPPs needs to explicitly consider their impacts on regional water resources.
This paper presents a techno-economic study to seek the feasibility about the proposed system that integrating solar-assisted pressure-temperature swing adsorption (PTSA) into an 800MWe coal-fired power plant. Solar energy has the potential to supply thermal energy demand for carbon capture, which can avoid the energy consumption of the traditional method such as the steam extraction. The performance of the proposed system is largely affected by the climatic conditions and solar collector's types. The assessment criteria include carbon emission intensity (CEI), levelized cost of electricity (LCOE) and cost of CO2 avoidance (COA). By the parametric analysis, the results show that CEI of the novel system with solar thermal collectors is approximately 2g/kWh lower than that of the referenced power plant with CO2 adsorption capture. In addition, CEI of the novel system can be further decrease with the decline of desorption temperature, adsorption pressure and desorption pressure. For the sake of lower LCOE and COA, the prices of the power plant capacity, adsorbents and solar collectors should be reduced. Specifically, LCOE of the system with evacuated tube collector will be lower than that of the reference system with CO2 capture as the price of solar field is lower than 46.08 USD/m2.
The integrated energy system which coordinates natural gas, renewable energy, and other energy subsystems is an effective way to promote a low-carbon economy. An effective framework for system assessment and optimisation is a critical issue. This paper takes a natural gas-wind-photovoltaic integrated energy system as the research object and uses the simulation software to analyse its techno-enviro-economic feasibility. Firstly, a mathematical model is customised to optimise the system installation and operation plans. Renewable electricity replaces some natural gas, resulting in pipeline pressure fluctuation. Here, the Stoner Pipeline Simulator software is used to simulate pipeline network operation to quantify the aforementioned pressure fluctuations. The proportion of renewable energy is gradually reduced until the network pressure fluctuation is less than 20% to ensure the stability of pipeline operation. Then, the optimal operation scheme can be determined. Taking three cities in Shandong, China, as cases, the results show that the proposed system is beneficial for urban energy internet development: (i) the total net present cost is reduced by 19.7%, 19.8%, and 20.8%, (ii) annual CO2 emission is reduced by 23.7%, 18.4%, and 12.2%; (iii) the levelised cost of energy is 0.142 $/kWh, 0.143$/kWh, and 0.153$/kWh.