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Paper has shaped society for centuries and is considered one of humanity's most important inventions. However, pulp and paper products can be damaging to social and natural systems along their lifecycle of material extraction, processing, transportation, and waste handling. The pulp and paper industry is among the top five most energy-intensive industries globally and is the fourth largest industrial energy user. This industry accounts for approximately 6% of global industrial energy use and 2% of direct industrial CO 2 emissions. The pulp and paper industry is also the largest user of original or virgin wood, with deleterious impacts on both human health and local flora and fauna, including aquatic ecosystems. This critical and systematic review seeks to identify alternatives for mitigating the climate impacts of pulp and paper processes and products, thus making the pulp and paper industry more environmentally sustainable. This study reviews 466 studies to answer the following questions: what are the main determinants of energy and carbon emissions emerging from the pulp and paper industry? What are the benefits of this industry adopting low-carbon manufacturing processes, and what barriers will need to be tackled to enable such adoption? Using a sociotechnical lens, we answer these questions, identify barriers for the pulp and paper industry's decarbonization, and present promising avenues for future research. •This review identifies carbon-intensive processes in the pulp and paper industry. •Presents decarbonizing practices, potential transformations and innovations. •Presents promising avenues for future research. •No agreed consensus on the most promising technologies to achieve net-zero in the pulp and paper industry. •Pulp and paper products are associated with other sociotechnical systems that create compelling interdependencies among industries. [ABSTRACT FROM AUTHOR]

Abstract Although paper production demonstrates high energy and water sensitivity in their life cycles, only a few systematic analyses have focused on these issues. Therefore, an energy and carbon coupled water footprint analysis of five types of Kraft wood pulp-based paper (i.e., specialty-, art-, household-, light coated-, and tissue paper) is conducted in this study to help improve the environmental performance of the paper industry. All investigations are conducted with an impact-oriented approach based on ISO standards. Results show that elemental-chlorine-free bleaching is more environmentally friendly than chlorination-alkaline extraction-hypochlorite bleaching, specifically for global warming, aquatic eutrophication, and human health (i.e., carcinogens and non-carcinogens). Gray water footprint along whole life cycles of each product is approximately twice of blue water footprint. Direct processes contribute approximately 50% to water scarcity, while their impact on aquatic eutrophication ranges from 0.002% to 50.72%. For other midpoints, indirect processes dominate the influences. Meanwhile, COD, BOD 5 , CO 2 , TP, Cr (Ⅵ), Ti, Hg, and As are key contributors. Finally, reusing sludge by direct burning in the recovery furnace, reclaiming organic compounds in black liquor before alkali recycling, and integrating black liquor gasification technology are expected to provide substantial environmental benefits. Amelioration of wastewater treatment, optimization of the national energy structure, and improvement of the efficiency of chemicals and freshwater are recommended. Highlights • Energy and carbon coupled water footprint analysis of Kraft pulp paper is applied. • The environmental benefit of black liquor recovery is dominated by reused alkali. • Direct processes contribute a lot to water scarcity and aquatic eutrophication. • COD, BOD, TP, and heavy metals are key substances. • Optimizing waste reuse and availability efficiency of chemicals is recommended. [ABSTRACT FROM AUTHOR]

This paper analyzes the carbon emission impact of pickup points in last-mile parcel delivery. Pickup points provide customers and delivery companies with an alternative to attended home delivery. The delivery company can drop a parcel off at the pickup point, such as a service desk in a grocery store or a parcel locker, from where the customer collects the parcel. Because of the potential efficiency gains for the delivery vehicle, pickup points are often presented as a sustainable alternative to home delivery. The efficiency gains for the delivery vehicle need to be weighed against customers traveling to the pickup point by car, however. The mathematical analysis presented in this paper integrates continuous approximation techniques to assess the potential for improved delivery route efficiency with multinomial logistic regression for estimating the travel distance and mode choice of customers collecting their parcels. The results challenge the suggestion that pickup points are a universally sustainable alternative to home delivery. The potential for a net positive carbon emission impact is greatest when pickup points are established in urban settings, while in rural settings, the carbon emission benefits derived from improved delivery route efficiency are quickly offset by the carbon footprint associated with customer travel. [Display omitted] [ABSTRACT FROM AUTHOR]

Renewable energies are a key to reducing carbon emissions and enabling access to affordable energy for rural populations in many low- and middle-income countries. For this reason, many governments have started to introduce auctions for off-grid renewable energy. Despite their relevance for clean, accessible energy, the factors for successful or failed off-grid renewable energy tenders have not been broadly studied yet. This paper investigates the success factors for the successful implementation of off-grid energy auctions to enhance rural energy access in low- and middle-income countries. For the scope of this research, the off-grid energy tenders are considered successful if they lead to cost-efficient outcomes, have a high implementation rate and improve the equality of access to energy. Using success measures and success factors from the state of knowledge on energy auctions, three real-world cases from Peru, Uganda and Senegal are analysed and compared. The investigations show that auctioneers should strike a balance between 1) economies of scale and streamlining administrative procedures, 2) allowing adequate product designs for a diverse group of beneficiaries and 3) attracting enough bidders in this relatively young sector. Moreover, this paper confirms that balancing the developers' risks and public risks is essential in designing off-grid energy tenders and that there are several ways to do this. Furthermore, the advantages and limitations of different support payment types are illustrated. Finally, regarding governance, the real-world cases in this research underscore the importance of clarity about responsibilities and procedures, without which significant delays can be incurred. • Off-grid energy auction organizers must balance developers' risks with public risks. • Fixed subsidies provide predictability to policymakers regarding public expenses. • Results-based financing encourages further expansion of projects. • Lack of clarity about responsibilities and procedures can lead to significant delays. [ABSTRACT FROM AUTHOR]

An optimization model that incorporates all combinatorically feasible inter-plant collaboration networks is developed using P-graph. It has been theoretically proven that time-sliced-based energy planning optimization has positive impacts and is capable of achieving carbon emissions reduction goals and minimizing costs simultaneously. However, as the number of entities increased, an exponential growth in possible combinatorial feasible coalitions is anticipated. Therefore, an extension of the P-graph optimization tool that is capable of generating all possible outcomes in multi-period P2P energy trading – PEP (P-graph for energy planning) is developed. The PEP software can be effectively used in modelling complex process networks graphically and solving optimization problems with the combined advantages of combinatorial algorithms and mathematical programming. In this paper, a systematic framework for implementing P2P energy trading using PEP software is proposed and demonstrated using a real-life case study. [Display omitted] • An optimization tool – PEP software is developed to model P2P energy trading scheme. • The software is capable of generating all possible financial outcomes effectively. • Optimal coalition structure is chosen based on the highest cost savings. • Marginal contribution analysis is done to ensure fair profit distribution. • The sample case study showed that entities can reduce electricity bills by 6.75 %. [ABSTRACT FROM AUTHOR]

Low-carbon and environmentally friendly development are becoming increasingly important in the metallurgical industry. In this study, the use of biomass as a source of both material and energy in metallurgical technologies is reviewed. The paper discusses the preparation of bio-based raw materials, their utilization in metallurgical processes, phytoremediation and metal extraction technology, and forestry as a carbon dioxide sequestration method. Bio-based raw materials, such as bio-based fuels, reductants, adhesives, and activated carbons, are found to provide energy, act as reductants and binders, dispose metallurgical flue gas, and adjust metal melt composition, thereby reducing energy consumption in metallurgical processes. Additionally, heavy metals can be enriched in plants through biomass-mediated soil remediation, and these metals can then be processed to obtain raw materials for metallurgical processes. Moreover, metallurgical waste heat can be used to prepare biomass as soil amendments, remediate deserts, and indirectly reduce metallurgical industry carbon dioxide emissions through forest carbon sinks. Based on these findings, the concept of biomass metallurgy is proposed, which promotes the use of biomass as energy or raw materials, ecological restoration and reforestation, and reduction of carbon dioxide and pollutant emissions in metallurgical processes. This study emphasizes the advantages of biomass metallurgy and encourages the development of low-carbon and green metallurgical processes. [Display omitted] • Development of metallurgical technologies using bio-based material and energy. • Bio-based materials including fuels, reductants, adhesives, and activated carbon. • Biomass used in metallurgy for combustion, reductants, pellets making, etc. • Heavy metals in hyperaccumulators extracted and recovered by biochemical methods. • Indirectly reducing CO 2 by transforming metallurgical waste heat into carbon sinks. [ABSTRACT FROM AUTHOR]

Carbon capture, utilization, and storage (CCUS) is a crucial strategy for achieving CO 2 emission reduction targets and mitigating the impacts of global warming and climate change. Among various CCUS technologies, chemical absorption of CO 2 has proven to be a mature and widely-used technique in various industrial sectors. However, the current CO 2 chemical absorption process involves large-scale equipment with low efficiencies, making it difficult to control. To address these issues, microfluidic devices have emerged as a promising technology to intensify the CO 2 absorption process by providing a smaller required volume, enhanced mass transfer, cleaner and safer operations, higher productivity, and more efficient energy use. This paper aims at presenting a comprehensive literature review on research advances of the microfluidic technology for CO 2 chemical absorption. The review covers various aspects, including microchannel geometries, two-phase flow patterns, mass transfer models, effects of operating factors, and measures to intensify the CO 2 absorption process. In addition, the paper discusses the measurement of interfacial and local parameters, such as liquid film thickness, velocity field, and local CO 2 concentration, which are primordial for understanding the transport phenomena and for optimizing the CO 2 absorbers. This paper may serve as an essential reference that contributes to the development and exploitation of highly-efficient microfluidic-based CO 2 chemical absorption technology for future large-scale industrial applications. [Display omitted] • Recent researches on microfluidic-based CO 2 chemical absorption are reviewed. • Absorption performance is determined by the mass transfer between CO 2 and absorbent. • Effects of influencing operational factors are discussed. • Optical techniques are frequently used to measure local & interfacial parameters. • Different techniques used to intensify the CO 2 absorption process are surveyed. [ABSTRACT FROM AUTHOR]

Under the carbon neutrality goal, the projects to develop zero-carbon microgrids are emerging all over the world. However, the categories, trends, challenges, and future research prospects of the zero-carbon microgrid are still unclear. To deal with this problem, this research first reviews the real-world and simulation cases of zero-carbon microgrids in recent years and classifies them into two categories, i.e., on-grid mode and off-grid mode. Then, three development trends of the zero-carbon microgrid are discussed, including an extremely high ratio of clean energy, large-scale energy storage, and an extremely high ratio of power electronic devices. Next, the challenges in achieving the zero-carbon microgrids in terms of feasibility, flexibility, and stability are discussed in detail. Finally, future research prospects in long-term low-cost energy storage, power/energy balancing, and stability control, are emphasized. [Display omitted] • This paper reviews the trends and challenges to achieve the zero-carbon microgrid. [ABSTRACT FROM AUTHOR]

There is a strong consensus that carbon emissions attributed to buildings are a major contributor to global warming. Reducing buildings’ carbon emissions becomes a matter of urgency and importance. However, despite the burgeoning body of knowledge of addressing buildings’ carbon emissions in the life cycle assessment (LCA) approach, the system boundaries of buildings’ carbon emissions and actually of their relevant research had never been made explicit systemically. As a result, the definitions of buildings’ life cycle differ considerably and the methods and models of analyzing buildings’ life cycle carbon emissions (LCCa) vary; all these lead to discrepancies in reported buildings’ LCCa and suggest a significant knowledge gap in effectively addressing the complex socio-technical features of buildings’ LCCa. This paper aims to provide a fundamental rethink of the boundaries of buildings’ LCCa for achieving meaningful benchmarking and learning in the future. The paper proposes a conceptual framework of system boundaries of buildings’ LCCa, and develops a regression model to predict such LCCa with strategies for enhancing the validity and reliability of the prediction. The framework elaborates the boundaries of buildings’ LCCa in the temporal, spatial, functional and methodological dimensions which together contain twelve variables, namely, life cycle stage, lifespan, climatic zone, geographic scope, LCA method, research method, unit of analysis, sources of emissions, building typology, level of prefabrication, building material, and density. The regression model is validated utilizing six representative cases of buildings’ LCCa selected globally. Inconsistent system boundaries adopted were found to have contributed to the discrepancies between the resultant buildings’ LCCa. The reconstructed system boundaries and developed regression model should facilitate a paradigmatic improvement in the body of knowledge of buildings’ LCCa. [ABSTRACT FROM AUTHOR]

The critical transmission hubs in global supply chain networks have great potential to reduce carbon emissions, yet this has not received much attention from existing studies. This research combines the structural path betweenness, an extended structural path analysis, and a multi-level modularity optimization algorithm to identify key transmission sectors, paths, and carbon communities in a global supply chain network using the environmentally extended multi-regional input-output analysis. The results show that (1) China's metal industry, power industry, and non-metallic industry are the most crucial transmission centers, and some sectors, such as the paper industry and textile industry in China, are also key transmission hubs, yet they are ignored by traditional accounting methods. From a national viewpoint, China is the most key transmission hub, and its high betweenness is mainly caused by domestic demand. Meanwhile, the CO 2 emissions transferred by China to satisfy foreign demand are mainly related to the US, ROW (especially the Asia-Pacific region), and Japan. (2) The transmitted carbon emission is mainly concentrated in the first four production layers, accounting for 69.46 % of the total. (3) The global carbon emission network can be divided into 20 carbon communities. And the largest communities are mainly led by mainland China. Most of the communities contain various national sectors, which offer evidence for international cooperation strategies. The results offer policymakers a new perspective on mitigating environmental stress. [Display omitted] • Critical sectors having higher betweenness are identified from a global level. • Key supply chain paths causing the high betweenness are identified. • Some critical carbon communities in the global carbon emission network are detected. • An extended structural path betweenness is proposed to find key supply chain path. [ABSTRACT FROM AUTHOR]

The paper empirically examines the cointegrating relationship between carbon emissions, energy consumption, trade openness and financial development in Pakistan using ARDL bounds test for cointegration procedure. Annual time series data is used for the period 1971–2011. The results reveal an inverted U-shaped relationship between carbon emission and energy consumption with a maximum threshold value of energy consumption per capita 640 kg of oil equivalent. Currently, the economy is operating below this level and therefore it is expected that carbon emission will continue to rise gradually over some time until the threshold level is reached. The lower than threshold level of energy consumption implies that scale and composition effects dominate the technology effect in terms of energy use. Further, the long-run results indicate that one percent increase in trade openness and financial development will increase carbon emission by 0.247% and 0.165%, respectively. The short-run elasticities are 0.122% and 0.087% for trade openness and financial development, respectively. The Granger causality results indicate a unidirectional causality from energy consumption, trade openness and financial development to carbon emission; and a bi-directional causality between energy consumption and financial development. In line with the results and given the growing focus on climate change effects in Pakistan, the paper discusses some policy issues for consideration and highlights the need to interpret elasticities with caution. [ABSTRACT FROM AUTHOR]

Storing CO 2 and H 2 in underground reservoirs represents an effective approach to sequester increasing amounts of captured CO 2 for carbon neutrality and to store H 2 to promote clean energy revolutions. However, commercial/pilot-scale CO 2 /H 2 storage sites are mainly restricted to conventional oil reservoirs or salt caverns – both capacity and geographic-location limited. This paper presents a systematic review of the feasibility and prospects of CO 2 and H 2 storage in fractured shale reservoirs as secure repositories. Both field pilot and laboratory studies of CO 2 injection in shales are cross-analyzed across various spatial and time scales, to provide a reliable and substantial basis to support new findings. The presence of suitable injectivity and adequate sealing capacity in shale are demonstrated. The fracture networks are shown to provide major storage space in shales, contrasting with the pore system in conventional reservoirs. This difference in storage mechanisms results in an overestimation in the storage capacity of shales when applying porous-medium-based methods. An underestimation in the mass of injection, however, is apparent from a single well for the reported cases due to unknown characteristics of underground fracture networks. The symbiotic storage of CO 2 and H 2 in shale is discussed in its feasibility and ability to improve both CO 2 storage but principally H 2 recovery – due to the presence of a gas cushion. A new equivalent-fracturing method is proposed as a supplement to recalibrate the over- and under-estimated prospects of CO 2 /H 2 storage in shales – a necessary component in reducing carbon emissions and accelerating the energy transition. [Display omitted] • Field pilots and laboratory studies are cross-analyzed and validated. • Fracture networks in shale reservoirs dominate CO 2 and H 2 storage. • Over- (in shales) and under- (in wells) estimations of CO 2 storage are revealed. • New estimation method is proposed for the technically achievable storage capacity. • Symbiotic storage of CO 2 and H 2 in shales is feasible and promising. [ABSTRACT FROM AUTHOR]

This paper aims to provide a comprehensive review and analysis of the potential impacts of Small-scale Renewable Energy Technologies (SRETs) in reducing deforestation, forest degradation and carbon emissions in the Eastern African region. A systematic review approach was used to select, critically analyze and synthesize findings of various studies in the region. The review showed that SRETs, if efficiently and uninterruptedly used, could significantly reduce household consumptions of traditional biomass and fossil fuels, and hence, can reduce deforestation, forest degradation and carbon emissions from biomass energy use at household levels. The FAO charcoal to dry wood conversion rate and the IPCC conversion factor of fuelwood from dry weight to CO 2 equivalent were used to estimate potential wood fuel and CO 2 e emissions savings. Our conservative estimates based on the analysis of the evidence indicated that domestic biogas and improved cook stoves distributed up to now have a combined potential of saving 0.307–3.100 million tons of wood fuel and 0.562–5.673 million tons of CO 2 e emissions per country per year. However, when compared to the annual biomass energy consumptions of each country, the potential wood fuel savings from the biogas plants and improved cooks-stoves disseminated so far do not appear to offset more than 7.2% of the national demands of the respective countries. The review suggests that building on the household level positive results for scale and lasting impact at national and regional levels requires addressing key policy, technical, financial and sectoral integration barriers. • Utilization of small-scale renewable energy technologies is growing in East Africa. • Use of clean energy could reduce household carbon footprint and reducing wood consumption. • At local level the impact of domestic biogas and improved cook-stoves is promising. • At wider geographic level the impact of the technologies is limited and undeveloped. • Achieving greater environmental benefits entails addressing critical barriers. [ABSTRACT FROM AUTHOR]

Regional integrated energy systems (RIES) have garnered increased attention because they highly utilize renewable energy, comprehensive efficiency, and flexible operation. However, the current research on RIESs is mainly based on burning natural gas and supplemented by renewable energy, which will consumes much primary energy and generates corresponding carbon emissions. Therefore, a RIES contained various renewable energy sources and station energy sharing was constructed in this paper. Both the collaborative optimization model, which considered the operating parameters and system configuration, and the hierarchical optimization model, which optimizes the equipment configuration at the upper layer and the operational parameters at the underlayer, were constructed, respectively. Taking a multi-function low-carbon park as an example, the isolated integrated energy system (IIES) and RIES performances were explored. Finally, the operation cost, carbon emission, and interactive power in the separated production system, IIES and RIES were analyzed and discussed from a long-short time scale perspective. The results showed that the carbon emission, interactive power, and energy supply cost of the RIES's unit area are 7.62 kg/m2, 10.07 kWh/m2, and 40.55 CNY/m2, respectively. Long time scale perspective (Years or months), RIESs could significantly reduce carbon emissions and interactive power. However, on a short time scale viewpoint (Hours), the system's instantaneous energy conservation and carbon reduction effect was general; meanwhile, the maximum grid-connected power in IIES and RIES was 2617.7 and 2712.0 kW, respectively. • A RIES is constructed integrating various renewable energy sources and energy sharing between stations. • Collaborative and hierarchical optimization is used to solve the complex RIES optimization problem. • Carbon emission and interactive power of the unit area for the RIES are 7.62 kg/m2 and 10.07 kWh/m2. • The maximum grid-connected power of IIES and RIES is 2617.7 and 2712.0 kW, respectively. [ABSTRACT FROM AUTHOR]

The building sector accounts for over one-third of global energy consumption and a significant share of carbon emissions. Improving building energy efficiency, particularly in the tropics, where most of the future development is foreseen, is thus crucial. One of the main factors that determine building energy performance is the building envelope. This paper presents a comprehensive review of the impact of several envelope design variables, such as thermal, optical, physical, and geometrical, on the energy performance of buildings in the tropics. A correlational analysis that elaborates on the effectiveness of each of these measures is discussed in detail. The findings indicate that insulation, glazing properties, and Window-to-wall ratio (WWR) are promising solutions for improving energy efficiency in tropical buildings. Among these, insulating the building envelope has the most significant impact on energy savings. The variables of building orientation and the thermal mass of building materials have the least influence on total energy consumption. The latter exhibits complex effects in regions characterized by hot-humid climates. An optimized design in cooling-dominated climates should have a large aspect ratio, a higher WWR in the north and south facades, and an ideal shading system. With all variables combined and appropriate ventilation, a building can save 35% of annual energy and up to 60% in some cases. This study further reveals that available research on the effect of building shape and the context of surrounding built environment on energy consumption remains limited. • Combining all envelope variables can provide annual average savings of 35%. • Average savings can drop by over 20% without insulation. • Insulation, WWR, and glazing type are the most promising solutions in Tropics. • Use insulation based on WWR, shading, thermal mass, and glazing type. • Shading, glazing, SHGC, and WWR have been mainly studied together. [ABSTRACT FROM AUTHOR]

The construction sector is a key actor in fighting climate change. A clear and comprehensive accounting of its carbon emission responsibility is the basis for effective emission mitigation actions. The intersectoral and interregional trade of the construction sector complicates emission responsibility allocation. Neglecting such trade flows or measuring them from a single perspective may cause the sector's emission status to be misinterpreted. Hence, based on the environmentally extended multiregional input-output model, this paper establishes the construction sector's multiprinciple emission responsibility accounting framework and conducts multiple accounting for China's construction sector. The emission distribution and transfer across regions and sectors are systematically revealed, and various accounting principles, regional clusters, and corresponding policy implications are compared and discussed. The results show significant differences in the emission responsibilities of the construction sector under different principles, indicating that the choice of principles will greatly affect the determination of responsibility and corresponding policy priorities, which requires careful consideration. The emission responsibilities in different regions also have notable heterogeneity under each principle and are further clustered into three main emission patterns, suggesting that classified and targeted emission mitigation strategies should be adopted. The emission transfer analysis demonstrates that the construction sector is a typical end-of-chain sector with high emission-pulling effects on upstream industries and tiny emission-pushing effects on downstream industries, resulting in varied incentive impacts under each principle. Overall, this study contributes extensive insights into the emission responsibility of the construction sector, supporting common but differentiated emission reduction targets and policy settings. • A multiprinciple carbon accounting model for the construction sector is developed. • The emission distribution and transfer across regions and sectors are explored. • Accounting principles, emission patterns, and policy implications are compared. • Great disparities under various principles alert multiperspective strategy setting. • Regional heterogeneity in emissions emphasizes differentiated mitigation actions. [ABSTRACT FROM AUTHOR]

This paper provides a review of negative carbon capture technologies. Based on these technologies, here it is proposed an innovative negative emissions power plant combining the generation and storage of energy from biomass, photovoltaic, and concentrated solar power, capturing and recovering CO 2 by producing H 2 or CH 4 as green energy carriers. The main features of the system are i) large-scale energy production system with negative CO 2 emissions; ii) 100% renewable system based on biomass and solar energy with the possibility of integrating other renewables; iii) synergistic integration of processes and systems; iv) recovery of O 2 generated by photovoltaic-driven electrolysis within the process of partial biomass oxycombustion and v) solar-driven limestone calcination. A detailed model of the entire plant is developed to evaluate the integration of the process. The model performance is assessed on an hourly basis throughout the whole year. The base case results show an energy consumption from 1 to 2.1 MJ/kg CO 2 to capture 60–77% of CO 2 emitted from the biomass plant and green methane production of more than 7500 tons/year. The negative emissions associated with the process are -612 kg CO 2 /MWh. It justifies the interest in the proposed negative emissions power plant. [Display omitted] • A synergetic integration of CO2 capture, energy storage and methane production is proposed. • A biomass power plant is considered, resulting in -612 kg CO2/MWh negative emissions. • Solar PV and CSP are integrated into the process to reduce the SPECCA to 1–2.1 kg CO2/MWh. • A large amount of solids storage is required to achieve 70–90% CO2 capture capacity. [ABSTRACT FROM AUTHOR]

Rapidly increasing catastrophic environmental incidents and changes in global climate have compelled researchers to take proactive measures for climate change mitigation. Consequently, reducing greenhouse gas emissions has become one of the most significant global targets. The transportation sector has a massive carbon footprint accounting for 22% of the total carbon dioxide emissions. In this regard, road transport contributes the largest fraction of the total emissions within the transportation sector. Conversely, the railway which is the cleanest form of transportation contributes slightly more than 1% of the total emissions. Moreover, since most of the rail systems are operated by government or private companies, it is relatively convenient to implement policies and replace conventional technology with environmentally friendly ones. This could be achieved by taking certain measures from technical and operational viewpoints for conserving energy to lower the carbon intensity of all transport modalities. Hence, this review paper focuses on investigating the railway sector to encourage a modal shift to the least carbon-intensive option. This study provides a critical review of the past and present rail technologies in terms of the environmental, economic, social, and technical perspectives. Moreover, a comparative assessment of the various locomotive types has been performed. The results reveal that battery-hydrogen hybrid locomotives are the best choice to be considered as a future locomotive technology. Hydrogen locomotives have the potential to be a promising alternative to diesel railway locomotives. However, certain technical barriers need to be overcome to enhance the overall system's performance and reliability to further improve the viability of its deployment in the railway sector. [Display omitted] • A critical review of the various rail technologies is provided through different viewpoints. • The assessment constitutes environmental, economic, social, and technical perspectives. • A decision-support tool for comparison of four rail technologies is also developed. • Battery-hydrogen hybrid locomotive results in the highest score of 1.47. • Standalone hydrogen locomotive results in the second highest score of 1.38. [ABSTRACT FROM AUTHOR]

With the intensification of global climate problems, the worldwide call for reducing CO 2 emissions is getting louder and louder. Low-carbon development has become the consensus of all countries. The electric heating film systems (EHFS) have recently attracted much attention as a clean and low-carbon building heating way due to the global target of carbon neutrality. This paper aims to provide a comprehensive review of the materials, performances and applications of the electric heating film (EHF). The conductive materials for the EHF mainly include graphene and carbon nanotubes (CNTs). Moreover, the main preparation methods are redox method, chemical vapor deposition (CVD), vacuum filtration method and screen printing. It was found that the EHF doped with the graphene or the carbon nanotubes (CNTs) has better performance on flexibility and thermal stability. The EHF prepared by chemical vapor deposition (CVD) has the best performance on uniformity and structure. However, this method is costly and difficult to implement for large-scale industrial production. Therefore, the screen printing technology remains the most widely used method. The composite EHF with two or more conductive materials (graphene and multi-walled carbon nanotubes (MWCNT)) has excellent mechanical properties, superb damage resistance and flexibility. In addition, the numerical simulation based on computational fluid dynamics (CFD) will be an important research method to investigate the indoor thermal environment of building heating by EHFS, which needs to be conducted in the future. The high performance EHF will be widely used in international applications such as artificial intelligence, wearable devices, aerospace, solar energy and medical protection. • The influence factors of electric heating film (EHF) conductive materials and composites are reviewed. • The methods of EHF and conductive materials are studied and synthesized. • The performance of the EHF is analyzed by means of experimental and numerical simulation. • The application of EHF is reviewed and prospected. [ABSTRACT FROM AUTHOR]

This is the first study utilizing carbon tax revenue to the renewable energy generation with Learning-by-doing (LBD) in the CGE model. This investigation demonstrates how induced technologically change (ITC) in the power sector offsets negative impacts on economic growth caused by the carbon tax in China. Business-as-usual scenario (without carbon tax) shows a significant impact of LBD on GDP growth and CO 2 emission reduction. Under a policy scenario with carbon tax, the results show that the negative impact on economic growth can be alleviated to less than 0.12%. If total carbon tax revenue was used for the subsidy to wind and solar power, even a positive impact on GDP growth will occur in the long-term. Therefore, the results verified and demonstrated the synergic effect of carbon pricing and the LBD process that economic loss caused by carbon tax could be offset by ITC in the renewable energy power sector. GDP decomposition shows that unexpensive electricity affected by ITC is beneficial to drive development of low-carbon energy, which can mitigate shock of carbon tax on heavy dependence on fossil fuel. This paper also provides policy implications that the LBD process will positively play a key role in energy structural shift under climate policy, making a great effort to climate mitigation. [Display omitted] • Combining bottom-up CGE model with top-down module Learning-by-Doing. • Utilizing carbon tax revenue to subsidy to renewable energy generation. • Providing optimistic impacts of carbon tax and subsidy on economic growth and reduction of carbon emission. • Learning-by-doing describes pathway of improved renewable energy. • Giving implication that Learning-by-doing can be boosted by environmental policies. [ABSTRACT FROM AUTHOR]

Energy subsidies can incentivise the overconsumption of energy resources and contribute to other economic or social distortions. In this paper, an ex-post analysis is presented that explores the extent to which electricity subsidy reform could have reduced Iran's energy demand during the period 1984–2017. It also quantifies the techno-economic and environmental benefits that could have been achieved through such reforms. A time-varying econometric model is linked to an energy systems optimisation model. The former estimates electricity demand under different subsidy removal scenarios, and the latter identifies the cost-optimal generation mix to meet the demand. The results of cost-optimal transition pathways under subsidy removal scenarios are compared with the real-world energy system development during the study horizon. The comparison reveals that the subsidy reform could have reduced the total cumulative electricity consumption by 22%. Renewable share in power generation could have increased from 5% to 15%. Moreover, the reform combined with a cost-optimal generation pathway would have saved $69 billion and avoided 944 million tons of CO 2 emissions. The analysis also shows that every five-year delay in subsidy removal causes about 100 million tons of additional CO 2 emissions. Finally, the paper presents lessons learnt for future energy modelling. • An ex-post analysis quantifies the benefits of energy subsidy reform in the power sector. • The total cumulative electricity consumption could have been reduced by 22%. • Renewable share in power generation could have tripled. • Subsidy reforms combined with cost-optimal generation could have saved $69 billion. • The paper presents lessons learnt for future energy modelling. [ABSTRACT FROM AUTHOR]

Energy subsidies can incentivise the overconsumption of energy resources and contribute to other economic or social distortions. In this paper, an ex-post analysis is presented that explores the extent to which electricity subsidy reform could have reduced Iran's energy demand during the period 1984–2017. It also quantifies the techno-economic and environmental benefits that could have been achieved through such reforms. A time-varying econometric model is linked to an energy systems optimisation model. The former estimates electricity demand under different subsidy removal scenarios, and the latter identifies the cost-optimal generation mix to meet the demand. The results of cost-optimal transition pathways under subsidy removal scenarios are compared with the real-world energy system development during the study horizon. The comparison reveals that the subsidy reform could have reduced the total cumulative electricity consumption by 22%. Renewable share in power generation could have increased from 5% to 15%. Moreover, the reform combined with a cost-optimal generation pathway would have saved $69 billion and avoided 944 million tons of CO 2 emissions. The analysis also shows that every five-year delay in subsidy removal causes about 100 million tons of additional CO 2 emissions. Finally, the paper presents lessons learnt for future energy modelling. • An ex-post analysis quantifies the benefits of energy subsidy reform in the power sector. • The total cumulative electricity consumption could have been reduced by 22%. • Renewable share in power generation could have tripled. • Subsidy reforms combined with cost-optimal generation could have saved $69 billion. • The paper presents lessons learnt for future energy modelling. [ABSTRACT FROM AUTHOR]

Investing in energy efficiency is considered to be an effective way to reduce the carbon emissions. However, the resulting CO 2 savings may be partially or totally offset by the rebound effect (RE). This paper goes beyond the traditional energy RE to investigate the rebound effect as related to CO 2 emissions, aims to explore the direct CO 2 rebound effect (CRE) in urban households at the provincial level. To achieve the objective, this study uses IPCC carbon emissions accounting method, then proposes an elasticity approach and constructs an individual fixed-effect variable coefficient panel data model. The results show that the total CO 2 emissions from household energy consumption were rising in most provinces during 2002–2017. The purchased electricity and heat CO 2 emissions are growing faster than combustion CO 2 emissions. Regarding the magnitude of the CRE, there are three types of direct CRE among urban households in China: the backfire effect, partial rebound effect and super conservation effect. Overall, the average direct CRE in urban households is 59.90%; specifically, the western region has the highest direct CRE (90.92%), compared with the eastern region (52.84%) and central region (24.88%). The government should take into account the CRE of households, in order to avoid overestimating the carbon reduction. Attention should also be paid to the differences between provinces when formulating energy policies. The analysis above helps local governments to formulate effective energy policies to promote households' carbon emission reduction. • This paper proposes an elasticity method for estimating CO 2 rebound effect. • The carbon emissions from household energy consumption are calculated. • There are three types of direct CO 2 rebound effect among urban households in China. • The average direct CO 2 rebound effect in urban households is 59.9%. [ABSTRACT FROM AUTHOR]

Several studies have found empirical evidence for the role of social capital in environmental management where a high level of social capital reduces emissions of pollutants, and other studies point out a negative relation between income and environmental performance. Therefore, this paper examines if and how social capital explains Swedish county-level per capita CO 2 emissions together with income in the period 2000–2017. A social capital composite index is constructed and different specifications of impacts on CO 2 emissions of social capital and income and functional forms, linear and non-linear, are tested. The system generalized method of moments (GMM) is used to account for endogeneity in the presence of dynamic and spatial effects. Robust results are negative and significant effects of social capital on emissions, and positive effects of income. Other common results observed are significant dynamic and spatial carbon emissions effects. • Paper examines the nexus between social capital, income and Swedish county-level per capita CO 2 emissions. • Results show significant negative and positive effects of social capital and income on emissions, respectively. • Enhanced trust and civic engagement could complement other public policy mechanisms in driving down CO 2 emissions. [ABSTRACT FROM AUTHOR]

Abstract: Thailand is heavily dependent on imported fossil fuels. The utilization of energy resources is the main source of CO2 emissions. Thus, restructuring current energy system is essential for the realization of low-carbon futures. Efficient and rational implementations of low emission reduction strategies and policies require application of energy system models that have the ability to estimate the baseline energy demand and CO2 emissions, and to explore technical and economic effects of different strategies over time. This paper reviews and discusses the perspective of low-carbon energy systems in the case of Thailand. It analyzes the projected development of energy system in Thailand. The literature on modeling of energy systems is analyzed and discussed. The paper presents a quantitative comparison of the selected energy model applications in terms of energy demand and energy-related CO2 emissions. The paper explores the potential pathways using findings from existing modeling studies to guide the development of a low-carbon energy system within a backcasting framework. It is found that there are wide ranges of projected emissions paths across the models. The findings suggest that there is sufficient technical potential to achieve a low-carbon target by 2030. [Copyright &y& Elsevier]

The following literature review sets out the state-of-the-art research relating to smart building principles and smart energy systems in UK higher education university campuses. The paper begins by discussing the carbon impact of the sector and the concept of 'smart campuses' applied to the sector in the context of decarbonisation. Opportunities and challenges associated with integrating smart energy systems at the university campus from a policy and technical perspective are then discussed. This is followed by a review of building and campus-scale frameworks supporting a transition to smart energy campuses using the BPIE' Smart Buildings' framework. The paper finds that the complexity of achieving net-zero carbon emissions for new and existing higher education buildings and energy systems can be addressed with the adoption of 'smart building principles' and integrating 'smartness' into their energy systems. Several universities in the UK and worldwide are integrating smart services and Information and Communication Technologies (ICT) in their operations following the smart campus premise. At the building level, existing frameworks often create conceptual roadmaps for the smart building premise or propose technical implementation and assessment methods. At university campus scale, implementation typically comes through single-vector interventions, and only few examples exist that propose a multi-vector approach. Comparisons of the drivers and the decision-making process are made, with carbon and cost reduction being the most prominent from leveraging distributed energy generation. Therefore, this study identified the need for a comprehensive technical or policy framework to drive the uptake of the smart energy campus, aiming to bring together the holistic value of smart energy campuses. • Systematic literature review of smart energy systems at university campus-scale. • UK Policy and technical pathways to smart energy integration. • A critical review of the existing building and university campus-scale frameworks. • A holistic decision-making framework for the integration of multi-vector smart energy system at university campus scale. [ABSTRACT FROM AUTHOR]

Concrete is the most highly used construction material globally. This is largely due to its durability, versatility and manufacture from inexpensive and readily available materials. Although concrete has become an essential and ubiquitous construction material for modern society, its use has significant environmental impacts. The full cement and concrete lifecycle, from production to final disposal, accounts for nearly 10% of global energy-related CO 2 emissions with the majority of these emissions produced from cement, which is the binding material that holds concrete together. The cement and concrete industry (CCI), which is integral to global infrastructure development, is therefore confronted with a growing need to decarbonize its operations and products, as well as to support the decarbonization of associated end-user sectors. This paper provides a systematic and critical review of more than 800 studies to highlight ways in which the CCI can decarbonize. A socio-technical perspective is used to understand the full range of industrial and economic activities where a decarbonized paradigm for cement and concrete production is relevant. This perspective is further used to assess key technical, economic, social and political factors that will drive a net-zero transition in the CCI over the long term. • Reviews the cement and concrete industry (CCI) decarbonization literature. • Describes the CCI's sociotechnical system and energy and environmental impacts. • Highlights barriers and opportunities for CCI decarbonization. • Outlines technologies and policies to mitigate negative CCI impacts. • Proposes gaps and future agendas for CCI decarbonization research. [ABSTRACT FROM AUTHOR]

Emission Trading Scheme (ETS) is one of the most important instruments introduced to meet carbon neutral targets internationally. To reduce carbon emissions, China has established eight regional ETS since 2013 to reduce carbon emissions. However, significant heterogeneities exist across the eight pilots, resulting in distinctively different carbon price movements. Traded as a financial asset, carbon allowance is vulnerable to internal and external shocks. Though carbon prices have been fluctuating fiercely since the inception of the carbon market, little is known about potential carbon price bubbles in any of these pilots. To this end, this paper resorts to the generalized sup Augmented Dickey-Fuller (GSADF) test, which allows the detection of multiple bubbles, as well as the date stamping of bubbles in carbon prices. For the first time, price bubbles are found in the Chinese carbon markets. The empirical results find three bubbles in Guangdong pilot, two bubbles in Tianjin pilot, and one bubble in Hubei pilot. These explosive episodes are closely related to immature market mechanisms and policy implementations. The results provide insightful implications for the upcoming unified national carbon market. • This paper detects the carbon price bubbles in Chinese markets. • Multiple bubbles exist in different pilots. • Not all pilots encounter bubbles. [ABSTRACT FROM AUTHOR]

This paper investigates the determinants of carbon emissions based on energy consumption, analyzing the data of 30 countries using nuclear energy for the period 1990–2014. Renewable energy and nuclear energy consumption are adopted as determinants, and real coal price and real GDP are used as additive variables. The panel cointegration analysis and Granger causality tests are conducted to investigating the relationship among the variables. First, the panel cointegration test results suggest that long-run equilibrium relationship exists among carbon emissions, renewable energy consumption, and nuclear energy consumption. The results of the long-run cointegrating vector and Granger causality tests indicate that nuclear energy does not contribute to carbon reduction unlike renewable energy. Thus, the development and expansion of renewable, not nuclear, energy are essential to prevent global warming. Though there is a concern that rising energy prices caused by the expansion of renewable energy may impact the economy negatively, our empirical results also imply that renewable energy consumption will promote economic growth. In other words, our evidence shows that using and expanding renewable energy is both economically and ecologically beneficial. [ABSTRACT FROM AUTHOR]

India's electricity requirements will continue to grow with its increasing population and urbanization. Climate change, increased carbon emissions, and the depletion of nonrenewable energy resources have forced India to shift to renewable energy resources. India's solar potential is large enough to provide 100-percent of its current electricity requirements if photovoltaic arrays and energy storage infrastructure of sufficient size is deployed. In this paper, we modeled the dynamics of net electricity input and output from a photovoltaic electricity (PV) system as it is built out to provide the entire electricity demand by 2050. The results showed that building a PV system large enough to meet the nation's entire electricity demand by 2050 is possible; however, it will require a rapid increase in the deployment of solar PV and the associated storage infrastructure over the next few decades. Such rapid expansion of the PV system will require substantial electricity allocation away from general societal use and towards building the photovoltaic system equipment and integrating it with existing infrastructure. This will lead to a short-term lack of electricity supply for general use by society. [ABSTRACT FROM AUTHOR]

Hydrogen-rich fuel for the gas turbines can be considered as a transient way from hydrocarbon fuel to zero-carbon hydrogen fuel. In this paper, thermodynamic analysis of a combined cycle power plant (CCPP) fired with a hydrogen-rich fuel obtained via various ways is performed to understand the effect of a transient to this fuel on the CO 2 emission as well as the efficiency of a power plant. Hydrogen-rich fuel with different content of hydrogen is analyzed. Two types of hydrogen-rich fuel are considered: fuel obtained via methane dilution with hydrogen (hydrogen from internal fuel supply infrastructure) — first case; fuel obtained via steam methane reforming (on-board hydrogen production technology) — second case. The first case showed that hydrogen addition to methane non-linearly leads to a decrease in CO 2 : hydrogen-rich fuel with 20% of H 2 volume fraction gives a reduction in CO 2 emission of 7.2%; 50% of H 2 gives 23.5% reduction; 75% of H 2 gives 51.1% reduction. The second case is considering hydrogen-rich fuel obtained via steam methane reforming using a renewable energy source. Hydrogen volume fraction up to 75% in hydrogen-rich fuel can be obtained after the reforming process. When 100% of methane is reformed, the reduction in CO 2 emission up to 27% can be achieved. The minimum achievable level in CO 2 emission is 75.17 g CO 2 /kW for an on-board hydrogen production technology via steam methane reforming which is corresponding to a hydrogen-rich fuel obtained via H 2 dilution up to 53%. • Hydrogen-rich fuel produced via either methane dilution with H 2 and CH 4 reforming is considered. • 20% (vol) and 75% (vol) H 2 gives a reduction in CO 2 emission of 7.2% and 51.1%, respectively. • Addition H 2 to CH 4 leads to an increase in LHV efficiency and decrease in HHV efficiency. • Hydrogen-rich fuel with up to 75% (vol) H 2 can be obtained via 4 reforming. • Methane reforming before combustion leads to a decrease in CO 2 emission up to 25%. [ABSTRACT FROM AUTHOR]

The Bretton Woods institutions and the G20 have undertaken the initiative to promote financial inclusion in Sub-Saharan Africa and South Asia to reduce the high rate of economic poverty. Due to advanced technology in financial services, Sub-Saharan Africa and South Africa have included a lot of people in the financial system. Thereby digital financial inclusion influences energy consumption and the environment by their pass-through effect on economic growth. This paper evaluates the expansion of innovative digital services and financial inclusion on energy consumption and the environment in different countries according to their geographical position. Regarding socio-economic indicators and the proportion of people who claim to be owners of an account at a bank or financial institution, SSA is still stagnating in poverty and has the lowest percentage compared to other regions. Using the Global Findex data, we find that higher financial inclusion proxies are related to higher energy consumption and CO2 emission. At the same time, the relationship is not always linear between technology, energy consumption and CO2 emission. • Most research focuses on the role of financial inclusion in economic growth , but in energy and environment is limited. • A comparative analysis of digital financial inclusion proxies of 39 countries based on their geographic position. • Social-economic indicators in East Asia and the Pacific region have almost reached these in Europe and Central Asia. • Compared to other regions, SSA is the only region stagnated in poverty. • Higher financial inclusion proxies are associated with higher energy consumption and CO2 emission. [ABSTRACT FROM AUTHOR]

This paper presents a mathematical model for a multi-period hydrogen supply chain design problem considering several design features not addressed in other studies. The model is formulated as a mixed-integer program allowing the production and storage facilities to be extended over time. Pipeline and tube trailer transport modes are considered for carrying hydrogen. The model also allows finding the optimal pipeline routes and the number of transport units. The objective is to obtain an efficient supply chain design within a given time frame in a way that the demand and carbon dioxide emissions constraints are satisfied and the total cost is minimized. A computer program is developed to ease the problem-solving process. The computer program extracts the geographical information from Google Maps and solves the problem using an optimization solver. Finally, the applicability of the proposed model is demonstrated in a case study from Oman. [Display omitted] • A multi-period hydrogen supply chain model with pipeline transport mode is presented. • A user-friendly computer program integrated with CPLEX solver is developed. • The proposed model is examined in a case study with 42 demand nodes. • The case study is tested for a trade-off between cost and carbon emissions. [ABSTRACT FROM AUTHOR]

Based on LEAP and WEAP, this paper establishes the coupled model of energy and water in cities. With Beijing as a case, 26 scenarios are designed to explore the energy saving/water saving of different policies in Beijing in the future and its nexus effect, including the sensitivity analysis of the results. The results show that the total energy consumption in Beijing will grow slowly by year. Carbon emissions will peak in 2020, and fluctuate after 2035 it will slowly increase until 2050. Total water demand is stable between 3.6 and 4.1 billion cubic meters. According to the forecasted water supply capacity, there is no shortage of water supply and demand. The proportion of groundwater from the source of water supply fell to 27%, and the proportion of water in the South-to-North Water Transfer increased to 40%. The total energy saving of the "13th Five-Year Plan" water saving policy is 1.003 million tons of standard coal, which is equivalent to 8.165 billion kWh of electricity. The energy saving policy has reached 276 million cubic meters of water, equivalent to 140 Kunming Lakes. The energy demand of residents' lives, service industry, construction industry and traditional manufacturing industry has a good correlation with water demand value, which proved they are important water-coupled sectors. In terms of energy-saving/water-saving effects in different scenarios and recent/long range periods, the industrial structure optimization policy showed good energy-saving potential in the short-term, but the long-term energy-saving effect was not obvious, while it was accompanied by an increase in water consumption. The irrigation technology innovation and planting structure optimization scenarios in the agricultural sector have better energy saving and water saving effects in the short term. However, with the occurrence and further expansion of water shortage, the medium and long term the water saving effect is sill, while the energy saving effect is not significant. The sensitivity analysis shows that the parameters of the scenario such as economic slowdown, industrial structure optimization, development of public transportation, and planting structure optimization are more sensitive. For the synergistic effect of water and energy conservation, the synergy effect is more obvious in the energy saving scenarios of the service industry and the industrial sector. For the policies of the same department, the synergistic saving effect of the situation of improving energy intensity is obvious. From the perspective of the difficulty in policy implementation process and overview effects, the water saving and energy saving policies of the industrial sector face more difficulties while implementation. The external power regulation policy and the capital rising residents' wareness of water saving policy has good performance both in the difficulty of implementation and overview effects. • This paper establishes the LEAP-WEAP coupled model of energy and water in cities. • Beijing energy saving policy has reached 276 million m3 of water, equivalent to 140 Kunming Lakes. • Beijing water saving policy is 1 million tce, equivalent to 8 billion kWh of electricity. • Water and energy saving policies of industrial sector face implementation difficulties. [ABSTRACT FROM AUTHOR]

Uncovering the contributions of each sector’s driving factors to the growth of national economic carbon emissions has great significance for China in developing its nationwide emission trading scheme (ETS). The paper applies the index decomposition analysis (IDA) and logarithmic mean divisia index (LMDI) model to discuss the underlying drivers behind China’s national economic carbon emissions during the period 1996–2012 from both sector and factor decomposition perspectives and accordingly offers policy proposals for China’s national ETS development. Major conclusions include: (1) Six heavy industry sectors, the transport & storage & post sector, and the construction sector are the largest contributors, and hence proposed for incorporation into the ETS’s coverage. (2) The rapid expansion of economic output dominantly increases carbon emissions. The design of cap on emissions should allow for a proper increment and establish a new entrant reserve to coordinate economic development. (3) As the dynamics of carbon emissions vary markedly across sectors, allowance allocation needs to consider the changing sectoral structure of emissions. (4) The combined effects of sectoral energy intensity and structure changes largely offset carbon emissions. Benchmarking is suggested as an ideal allocation mechanism, and the setup of sectoral carbon intensity benchmark should synthetically evaluate the potential impacts of related factors. (5) Manufacturer-based manner and carbon offset mechanism are respectively recommended for the initial implementation of carbon trading in the transport & storage & post sector and the construction sector. [ABSTRACT FROM AUTHOR]

Biochar amendment has been proposed as a promising solution to mitigate greenhouse gas (GHG) emissions from agriculture and sustainably enhance crop yield. However, the net GHG mitigation potential of biochar remains uncertain, especially the controversial results from field and laboratory experiments. Using 9970 published observational data derived from 592 peer-reviewed papers, this study highlighted the effects of biochar in field experiments on crop yield, soil organic carbon (SOC) stocks, carbon dioxide (CO 2) and methane (CH 4) fluxes, and soil nitrogen (N) dynamics (i.e., soil inorganic N stocks, nitrous oxide [N 2 O] emissions, ammonia [NH 3 ] volatilization, and inorganic N leaching). Overall, field data indicated that biochar significantly increased gross SOC stocks (26.6%) and crop yield (15.7%), reduced soil CH 4 (−14.8%) and N 2 O (−23.1%) emissions, and ammonium (−24.9%) and total inorganic N leaching (−23.2%) but had no effect on soil CO 2 emissions. Whereas laboratory data generally showed greater effect sizes of biochar on these indictors. Global warming potential was decreased only in field experiments, but both experiments showed similar reductions in GHG intensity. Both experiments suggested that soil and biochar cation exchange capacity, pH, biochar application rate, and nitrogen fertilization interactively regulated biochar effects on crop yield and GHG emissions. The unrealistically high rates of biochar in laboratory experiments may overestimate its benefit on soil C sequestration and/or underestimate its mitigation potential. These findings provide a comprehensive view that biochar amendment may serve as a viable climate-smart agricultural practice that can help in partial achievement of multiple sustainable development goals. • Biochar is an effective strategy for climate-smart agriculture. • Biochar added to field (∼20 Mg ha−1) can increase gross SOC stock by ∼27%. • Biochar can decrease global warming potential and greenhouse gas intensity. • Unrealistically high biochar rates in lab overestimated soil carbon sequestration. [ABSTRACT FROM AUTHOR]

Meeting decarbonization goals requires taking significant action on electricity systems, which are a major source of CO 2 emissions. Decarbonizing island electricity systems raises additional challenges due to their heavy historical dependence on fossil fuels and strict power-reserve and reliability requirements. To address this challenge, this paper presents a comprehensive optimization model for long-term capacity planning of island electricity systems. Our model determines an optimal mix of generation and transmission capacity to satisfy energy demand at least cost while respecting the strict technical constraints that are inherent in island systems. In addition, our model considers the use of thermal and renewable generation, electric vehicles providing electricity-system services, batteries, pumped-hydroelectric storage, and ac and high-voltage dc transmission lines. We demonstrate our model with a case study of the Canary Islands archipelago. Our results show that combining the aforementioned technologies reduces generation costs by up to 25% and capacity requirements up to 50% (relative to a case without the technologies). In addition, without any mechanism to internalize the social cost of carbon, fossil-fueled thermal generation is the lowest-cost source of energy. Environmental considerations demonstrate the benefits of renewable generation and result in these carbon-free energy sources supplying about 40% of the energy mix. [Display omitted] • Carbon pricing can increase renewable-energy supply up to 40%. • Energy storage reduce costs up to 23% and favors more renewable-energy capacity. • Transmission interconnectors reduce costs but do not increase renewable-energy use. • Combining technologies reduces costs by 25% and capacity requirements by 50%. • Strict reserve requirements may keep renewable-energy shares below 3%. [ABSTRACT FROM AUTHOR]

Reducing carbon emissions and managing the aging crisis represent two major challenges in China that involve various requirements for continued economic growth. This paper investigated the relationships between population factors and carbon emissions and further explored the impact of population aging on carbon emissions at the national and regional levels based on the STIRPAT model and provincial panel data from China. Our results show that at the national level, population aging and population quality are positively correlated with China's carbon emissions. The impact of the population living standard on carbon emissions exhibits an urban-rural difference. At the regional level, the impact of population aging on carbon emissions exhibits regional differences. [ABSTRACT FROM AUTHOR]

Biomethane is a viable alternative to natural gas and diesel for decarbonising hard-to-abate sectors such as agriculture, industry and heavy transport. Unlike conventional biogas upgrading, photosynthetic biogas upgrading cogenerates biomethane, biofertiliser and microalgal bioproducts with the potential to improve resource utilisation and process performance in a circular economy. In this paper, a photosynthetic biogas upgrading-based polygeneration process is proposed and analysed to co-produce biofuel (biomethane), bio-fertiliser (digestate) and food (Spirulina powder, protein supplement) using agricultural feedstock. Based on a multi-criteria performance assessment, the economic and environmental benefits of the process are demonstrated. Thermodynamic performance of the process revealed that reducing the energy for greenhouse heating to cultivate microalgae would enable a higher energy output than input. Using economic allocation, a carbon footprint of biomethane less than 10 gCO 2-eq /MJ (lower than 32.9 gCO 2-eq /MJ for sustainable biomethane use in transport in the EU Renewable Energy Directive (Recast) (RED-II)); Spirulina protein of 0.8 kgCO 2-eq /100 g protein (compared to 50 kgCO 2-eq /100 g protein for beef); and digestate of 0.4 kgCO 2-eq /kgN (comparing positively to 1.5–3 kgCO 2-eq /kgN for synthetic nitrogenous fertiliser) was achieved. Unlike the current RED-II mandated methodology, the analysis established that the energy, CO 2 emissions, land and water footprints of each co-product are best represented using an economic allocation principle. Based on the extended nutrition profile, Spirulina as a complete food outperforms most meat and plant-based protein alternatives in terms of CO 2 emissions, land, and water footprints. [Display omitted] • Grid-quality biomethane (<2.5 % v CO 2 , <1% v O 2) emissions were below 10 gCO 2-eq /MJ. • Carbon footprint of Spirulina powder as food was 0.8 kgCO 2-eq /100 g protein. • The carbon footprint of digestate as a fertiliser was 0.4 kgCO 2-eq /kgN. • Sustainability of co-products is best represented using economic allocation. [ABSTRACT FROM AUTHOR]

To keep temperature rise well below 2 °C, production systems should be synthesised in a way that are regenerative, climate-resilient, and equitable, and to maintain biodiversity to preserve life and meet future human needs with the integrity of nature. In line with this approach, this paper presents a stepwise transition to a regenerative energy system in the EU by 2050, with the aim of going beyond carbon neutrality and achieving annual net negative emissions. A mixed-integer linear programming model is developed with the goal of maximising the Sustainability Net Present Value while achieving a balanced solution between all the three basic sustainability pillars. In order to obtain a regenerative system design, the annual self-sequestration of CO 2 by the Earth was evaluated based on the amount of CO 2 released into the atmosphere and the change in atmospheric CO 2 concentration. The impact of different CO 2 emission reduction scenarios on the atmospheric CO 2 concentration until 2050 was evaluated. The results show that carbon neutrality at the global level could be achieved by 2050 with a 1.63% annual reduction in anthropogenic CO 2 emissions. Moreover, the results indicate that if carbon emission neutrality is achieved at the global level in 2050, it could be achieved in the EU as early as 2039, given the Earth's self-sequestration capacity. To go beyond carbon emissions neutrality at the EU level, electricity demand is expected to nearly double, particularly due to the electrification of road transport, the use of heat pumps for heating residential and the tertiary sectors, 6G and IoT widespread out etc. • A critical review of sustainable heat production technologies. • A MILP model to achieve carbon emissions neutrality or negative net emissions in the EU by 2050. • Cross-sectoral synthesis of regenerative energy systems – beyond sustainability. • Assessment and prediction of Earth's self-sequestration in the synthesis of regenerative energy systems. [ABSTRACT FROM AUTHOR]

Driven by the recent trends towards a smart power system configuration, there has been a greater focus within the literature on the integration between supply and demand-side resources. The contribution of this research is multifold since it provides a timely and required study, offering valuable insights into how the integration between Demand-Side Management (DSM) resources with clean energy supply options might affect the long-term power planning strategies in high-renewable electricity systems. The innovative aspects of this study are strongly related to a framework proposal for assessing the co-benefits between energy efficiency and demand-response on renewable-based energy systems from a long-term perspective using a co-optimization modelling approach. Overall, the results indicate that a clear benefit of implementing DSM strategies is the percentage reduction of the new installed capacity (−1.0% to −20.6%), CO 2 emissions (−2.4% to −11.8%), and total system costs (−0.5% to −15.8%) for all scenarios compared to Business-As-Usual scenario. The evidence from this study suggests that investments in Energy Efficiency (EE) seem more economically valuable than investing only in Demand-Response (DR) strategies. However, integrating EE and DR would empower the overall power system benefits. Strong evidence for a higher potential to delay investments was found for all scenarios for the first ten years of the planning period. Our findings might provide valuable insights to both governments and policy-makers by delivering supportive information in scaling up EE investments. The methodology proposed offers essential contributions to the scientific community and would benefit energy systems research beyond the cases addressed in this paper. • Integrated assessment of demand-side management for renewable-based energy systems is performed. • The methodology accounts for long-term reinvestments in energy efficiency. • A co-optimization modelling approach is used for the scenario analysis. • Combining energy efficiency and demand-response investments empower the economic benefits. • Demand-side strategies seem to decrease the natural gas capacity for all scenarios. [ABSTRACT FROM AUTHOR]

Consumer adoption of renewable energy technologies such as heat pumps for home heating is crucial in reducing greenhouse gas emissions and reliance on imported fossil fuels. In recognition of their potential, policymakers in several countries have introduced various financial incentives to encourage the uptake of renewable energy technologies. However, consumers' purchasing decisions and choice of a particular technology is a complex process that goes beyond financial aspects. In this paper, we examine the adoption decisions and diffusion of heat pumps for residential home heating using an agent-based modeling and simulation approach. In particular, we model the influence of three factors: economic, psychological, and social networks, on the future uptake of heat pumps. We utilize recent nationally representative Irish household survey data and historical heat pump uptake data to derive model parameters for decision rules based on empirical data and simulate the adoption of heat pumps in existing Irish homes until 2030. We further analyze the implications of those future uptakes on electricity demand, bill savings, and reduction in CO 2 emissions. The findings of this research based on the case study of Ireland should be useful to policymakers and companies in devising monetary and non-monetary interventions aimed at increasing future actual uptake of heat pumps and other renewable energy technologies. • Develops an agent-based model to study the adoption of heat pumps in a market at an early stage of development. • Incorporates economic factors, psychological aspects, and social networks in adoption decisions. • Uses representative household survey data to populate and initiate model simulation with real-world preferences. • Analyzes implications of future uptake on electricity demand, cost savings, and CO 2 emissions. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) are believed as efficient solutions to reduce carbon emissions and fossil fuel reliance in transportation sectors. Yet, the ever-increasing penetration of EVs also poses great challenges for distribution grid planning and operation. As a research hotspot, the vehicle-to-grid (V2G) technology could not only relieve the adverse effects of large-scale uncoordinated EV charging but also offer varied auxiliary services for the utility grid via the proper charging/discharging schedule. In this paper, a comprehensive review of distribution grid architectures, grid connection infrastructures and standards, and typical applications is conducted from the perspective of EV-grid integration and V2G operation for the first time. The nanogrid, microgrid, and cluster architectures that are critical components in active distribution grids are all involved in the discussion. Considering EV's triple roles played in grid interaction, the corresponding infrastructure and grid-connection standards, as well as bidirectional/unidirectional charger topologies, are overviewed. Then, four-type nanogrid and microgrid architectures are reviewed and fully evaluated in six aspects, viz., charging demand compatibility, power quality severity, V2G availability, architecture scalability, local control complexity, and technology maturity. The assessment result reveals that the hybrid AC/DC-coupled architecture based on advanced interlinking converters has flexible power flow control and power quality compensation capability, thus facilitating the EV-grid integration and V2G operation effectively. The assessment for three-type cluster architectures indicates that the hybrid parallel-series microgrid cluster has balanced performance in complexity, cost, redundancy, and reliability. Finally, the typical applications of the nanogrid, microgrid, and cluster with EVs integration are exemplified and discussed. • The emerging DC-powered converter topologies to interface EVs are identified and discussed. • Extensive nanogrid, microgrid, and cluster are contained in the architecture discussion. • Extensive six indexes are developed to evaluate four-type nanogrid and microgrid architectures. • Comprehensive assessment of varied power architectures is completed in view of the EV-grid integration and V2G operation. [ABSTRACT FROM AUTHOR]

Cloud Computing services can be accessed anytime, anywhere via the Internet. The overwhelming growth of cloud data centers over the past decade has increased their costs as energy demands have risen. As a result, higher carbon dioxide emissions and other greenhouse gasses are putting a strain on our ecosystem. The main objective of this study is to reduce the power consumption in cloud computing with no or negligible trade-offs in quality of service. This paper presents a new algorithm called the energy efficiency heuristic using virtual machine consolidation to minimize the high energy consumption in the cloud. By setting two thresholds, hosts are classified into three main classes. The designed model reallocates virtual machines from one physical host to another to minimize energy consumption. The results of the proposed algorithm have been obtained in terms of virtual machine migrations, performance degradation caused by migration, service level agreement violations, and execution time, showing a significant improvement over state-of-the-art techniques. • A novel scheduling mechanism EEHVMC to reduce energy consumption is designed. • The designed EEHVMC can also reduce VR migration, and service level agreement violations. • The designed model is based on the real-time cloud computing. [ABSTRACT FROM AUTHOR]

Clean energy heating electrification programs provide a promising way to reduce carbon emissions from fossil fuel combustion and consumption. This work studies the cost competitiveness of clean energy heating technologies under three dynamic mechanisms: investment costs, subsidy policies, and operating costs with real data. It provides key insights into the cost competitiveness of the different heating technologies deployed in different areas, as well as their sensitivity to the three dynamic mechanisms. The results show that currently, the distinct heating programs are more cost-efficient in the urban area with existing heating networks. The average payback period of all district clean energy heating programs in the urban area is 14.9 years, while that of the individual clean heating programs is 24.7 years. The individual heating programs are becoming increasingly cost-competitive with the incentive mechanisms, especially the electricity pricing mechanisms. Moreover, individual heating technologies present remarkable advantages on flexibility and sustainability in the long run. According to the technology diffusion model proposed in this paper, the individual clean heating programs will occupy more than 50% of the market share in 2050 under the comprehensive effect of CAPEX, government subsidies, and OPEX. The real-world results and analysis render references to shape the pathway of clean energy heating electrification in Northwest China and other regions with a similar situation. • Describe ten typical clean energy heating electrification programs. • Analysis of the cost competitiveness of those programs under economic, technical, and political factors. • Predict the development pathway of each clean energy heating electrification program. [ABSTRACT FROM AUTHOR]

The most important aspect of sustainability in manufacturing is the preservation of energy and natural resources. For modern production, optimized processes that minimize negative impacts on the environment are becoming increasingly important. This can be achieved by increasing energy efficiency through low, clean, and renewable energy consumption. There are many ways to produce less pollution, emissions, and waste in machining: by using more environmentally friendly cooling methods; by applying methods that reduce or eliminate the need for utilization of cooling lubrication; improving the energy efficiency of machining operations; determining the optimal cutting conditions that save resources by increasing machining productivity or reducing the metal removal rate (MRR); minimizing power consumption; and reducing carbon dioxide emissions. This article gives an idea of modern manufacturing with a focus on analyzing the current state of machining operations in terms of saving production resources and ensuring more environmentally friendly production using greener cooling methods of machining such as Dry, Conventional cooling systems, Minimum quantity of lubricant (MQL), Minimum quantity of cooling lubrication (MQCL), Nanofluids, Biodegradable Vegetable Oils, Cryogenic Lubrication, and High-Pressure Cooling (HPC). Finally, the important modern trends of providing resource-saving and environmentally efficient technologies in modern sustainable manufacturing are discussed in this paper. • Present review article deals with the sustainability and resource saving aspects during machining operations. • Different cooling conditions were presented. • Waste minimizing, recycling, pollution etc. were discussed during machining oeprations. [ABSTRACT FROM AUTHOR]

The transport sector is answerable for around a quarter of the global CO 2 emissions sent into the atmosphere, and 50% of the greenhouse gases in the cities. Considering a staggered introduction of renewable sources in the electricity mix, the introduction of electric vehicles (EVs) in the urban transport network arises as a necessary environmental solution. However, their integration is facing a wide range of barriers, many of them only qualitatively known, or uncertain. This paper presents a multicriteria methodology to assess such obstacles to the electrification of urban transport of Mediterranean flat medium cities. This analysis considers context analysis, literature review, and the application of the Multi Criteria Decision Making Method: Analytic Network Process, with the aid of a panel of experts representing quadruple helix involvement (Government, Business, Society and Academia). As a case study, the city of Valencia (Spain) was chosen, which has been in a deep transition of mobility in recent decades. Results revealed that the most influential barriers turned out to be the insufficient subsidies for EVs' development, the battery autonomy power and the CapEx of batteries. Moreover, private passenger transport followed by freight transport ranked as the most affected urban transport alternatives. • Multicriteria method to assess the obstacles to the introduction of EVs in Mediterranen cities. • The methodology includes context analysis, literature review and ANP application. • Insufficient subsidies results the main barrier for EVs' development. • Private passenger transport is the most affected urban transport alternative. [ABSTRACT FROM AUTHOR]

The aim of this paper is to provide new empirical evidence on the impact of economic growth and energy use on carbon emissions (CO 2 emissions) for fifty eight countries over the period 1990–2012 by using a panel data model. We also apply this model in order to implement three regional sub-groups; European and North Asian region, Latin American and Caribbean region, and the Middle Eastern, North African and sub-Saharan region. The results revealed that the energy use has a positive impact on the carbon dioxide emissions for all the panels. The impact of economic growth on the environment has received increased attention as global warming and other environmental problems become more serious. Indeed, the per capita GDP has a positive and statistically significant impact on carbon for the global panel, for the Europe and North Asia, and for the Middle Eastern, North Africa, and sub-Saharan Africa. Furthermore, our empirical results indicate the presence of an inverted U-shaped curve between carbon dioxide emissions and GDP per capita. [ABSTRACT FROM AUTHOR]

A Data center comprises of servers, storage devices, cooling and power delivery equipment to support other components, exchange data and information to provide general services such as software-as-a-service (SaaS), platform-as-a-service (PaaS), and Internet-as-a-service (IaaS). Data centers require massive amount of computational power to drive complex systems. In return these massive systems bring many challenges and concerns including power dissipation and environmental sustainability. Higher power demand in data centers and changes in computing technology together to maximize data center performance has led to deploying multitude methods to estimate power intensity. Energy cost increment, global economic downturn, and global warming and other concerns have resulted in new research in achieving power efficient data centers. The research proposed in this paper evaluates three task scheduling algorithms RASA, TPPC, and PALB to get the most energy efficient task scheduling algorithm to be used in data centers for measuring their performance and efficiency. The three algorithms are evaluated for performance using three parameters; power efficiency, cost effectiveness, and amount of CO 2 emissions. On top of that data center location and climate conditions are also considered and analyzed as parameters as they directly effect the operating costs, the amount of power consumption and CO 2 emission. To minimize the power wasted by data center cooling systems is directly related to data center location and climate change. CloudSim simulator is used to implement the algorithms on an IaaS cloud infrastructure, to calculate the power consumption, and to analyze each algorithm׳s behavior for different parameters. The results generated clearly shows that TPPC is the most efficient algorithm due to less amount of power consumption and low volume of CO 2 emission; however its implementation cost is bit higher compare to PALB and RASA. [ABSTRACT FROM AUTHOR]

This paper aims to analyze and compare the driving forces of the carbon dioxide emissions of the six highest emitters of the world, namely, China, the United States of America, the European Union, India, Russia, and Japan, which are responsible for more than the 67% of the emissions, during the period 1990–2018. The analysis is based on an enlarged Kaya-LMDI decomposition, considering five driving forces and a Granger causality study. Both techniques allow us to disentangle the relationship among the different driving forces and how they change from country to country. The main conclusion from the Kaya-LMDI analysis is that economic growth has been the main driving force that increases CO 2 emissions, and to a much lesser extent, the increase in population in most of the six analyzed economies. On the other hand, energy intensity is the main factor for reducing CO 2 emissions. Surprisingly enough, the end-use fuel-mix term seldom contributes to the decrease of the emissions, which proves that the use of renewable energy should still be actively promoted. It is worth highlighting the different behavior observed between the four developed countries and the two most populous developing ones, China and India. The Granger-causality analysis suggests that energy intensity Granger causes GDP in the developed countries, energy intensity also Granger causes CO 2 emissions in half of the countries and, GDP Granger causes CO 2 emissions only in one case, Japan. [Display omitted] • China and India should greatly improve their energy intensity and energy mix contributions to reduce their CO 2 emissions. • The USA and the EU shown promising trends concerning energy intensity and energy mix contributions capable of reducing their global CO 2 emissions. • Granger causality analysis suggests that energy intensity Granger causes most of the rest of driving forces. • Emission intensity of China, India and Russia is around four times greater than that of the USA, the EU and Japan. [ABSTRACT FROM AUTHOR]