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This study investigates the impact of incorporating lime mud (LM) as a filler material to develop sustainable, cementless ultra-high performance concrete (UHPC) by replacing silica powder (SP) and silica sand (SS) at varying percentages. Flowability analysis reveals that LM, with its distinctive particle size, influences flow characteristics differently at different replacement levels. Compressive strength was improved by 5.4% with 30% SP replacement, showcasing the role of LM in nucleation, as well as its particle size advantage. The heat of hydration analysis indicates that LM likely influences the early curing stages, enhancing reactivity and nucleation. TGA analysis also confirms that LM plays a role in hydration reaction, influencing weight loss and hydration peaks. The mercury intrusion porosimeter results show the impact of LM on pore distribution, with 30% for SP and 50% for SS replacements, favoring denser matrices. Life cycle assessment (LCA) demonstrates reduced CO 2 emissions and favorable environmental performance, highlighting the sustainability potential of LM replacements. Overall, the incorporation of LM in UHPC shows promise in terms of enhancing its mechanical properties and environmental sustainability. [Display omitted] • Lime mud (LM) in UHPC boosts material strength, leading to denser, more effective concrete. • LM enhances hydration, flowability, and refines pore structure. • High LM ratios in UHPC increase sustainability and reduce CO 2 emissions. • LM's use in UHPC significantly advances its mechanical properties and eco-friendliness. [ABSTRACT FROM AUTHOR]

• The North-South gap of China has widened in recent decades. • This paper focused on the North-South industrial transfer and its impact on emissions. • The North-South transfer aggravated the imbalance of carbon emissions across regions in China. • The spillover effect is the dominant path behind the impact of the transfer. In recent years, the gap between the north and the south of China has been expanding, showing a decreasing proportion of value-added and an increasing proportion of carbon emissions in the north of China, and vice versa in the south of China. Based on the most recent inter-provincial input-output table of China in 2012 and 2017, this paper focused on the North-South industrial transfer of manufacturing, quantified its impact on regional carbon emissions, and decomposed the path of impacts. The results suggest that the North-South industrial transfers of China during 2012-2017 indeed aggravated the imbalance of carbon emissions in the north and the south of China. Further explorations of path decompositions show that the spillover effect through production linkages is the major path where industrial transfer influences regional carbon emissions, particularly in the north of China. The results provide insightful policy implications for the achievement of carbon emissions reduction targets in China as well as the globe. [ABSTRACT FROM AUTHOR]

Hydrogen as a clean energy to deal with carbon emissions has been favored by many scholars, while the problems of low efficiency and high energy consumption in the process of liquefaction storage and transportation have become one of the important factors restricting the development of it. The combination of heat exchanger and ortho-para (O–P) hydrogen converter has attracted considerable attention as a high efficiency and low energy consumption technology. In this paper, based on the catalyst-filled spiral wound heat exchanger (CSWHE) and coupled with ortho-para hydrogen conversion, the flow and heat transfer characteristics of gaseous hydrogen are studied. Firstly, low-temperature O–P hydrogen catalytic conversion experiments and flow characteristics experiments were carried out by filling catalyst in the heat exchange tube. and an equation for calculating pressure drop in the section filled catalyst was proposed. Secondly, a new numerical model was established validated by the experiments. The influence of catalyst on heat transfer and the effects of velocity on the heat transfer performance and O–P hydrogen conversion efficiency were studied by numerical simulation. Finally, this paper analyzed the significant factor affecting the para hydrogen content at outlet: reaction time. And an equation for calculating para hydrogen content at outlet with reaction time was proposed. This study is expected to provide a reference for the design of CSWHE. • An isothermal reactor is designed and employed to low-temperature ortho and para hydrogen catalytic conversion experiments. • A new pressure drop calculation equation for porous region is proposed by modifying Ergun equation. • A new numerical model is established to study the coupling mechanism of flow and heat transfer. • The key factor affecting the catalytic conversion of ortho and para hydrogen is pointed out: reaction time. [ABSTRACT FROM AUTHOR]

With the development of energy technology, hydrogen is gradually becoming widely used. China is also rapidly developing its own hydrogen energy industry in an effort to accomplish the "dual carbon target'. Hydrogen from methane is one of the mainstream sources, of which hydrogen from methane cracking is the decomposition of methane into hydrogen and solid carbon, with the solid carbon also having a high economic value. In particular, this technology does not emit carbon dioxide, which is very friendly to the environment, but it cannot avoid larger energy consumption. In contrast, hydrogen production from methane cracking driven by solar energy not only combines the characteristics of no CO 2 emission, but also greatly reduces the consumption of primary energy, which is the future development trend of hydrogen production from methane. This paper provides a brief overview of the various technological pathways for methane to hydrogen production in the context of China's actual development, focusing on the current status of the development and application of solar methane cracking to hydrogen production technologies at home and abroad. Among them, this paper mainly discusses the characteristics of solar reactors of different sizes and structures, and summarizes the results of related optimization studies. Meanwhile, the application of catalysts in solar reactors and the problem of carbon deposition are analyzed, and the practical application of solar methane cracking hydrogen production system is outlined. Finally, the future development of solar methane cracking hydrogen production technology is prospected from the national situation of China. [Display omitted] • Solar methane cracking for hydrogen can reduce emissions and energy consumption. • The current state of research on solar reactors is summarized. • Solar methane cracking requires higher performing catalysts. • Providing insights into the future development of solar methane cracking in China. [ABSTRACT FROM AUTHOR]

Urbanization and the release of carbon emission are two significant features of contemporary economic and social progress in China. However, there are few studies that consider how urbanization policy goals affect carbon emission. This paper aims to study the nonlinear effects of urbanization policy goals on carbon emission in 13 cities of the Beijing-Tianjin-Hebei region. In this paper, a multi-dimensional spatial disturbance grey model is proposed. Based on matrix perturbation theory, this paper explores the spatial perturbation bounds of the novel model and verifies that the spatial property of the model is consistent with the viewpoint of the First Law of Geography. Then, the novel model is used to predict the urban carbon emission under different urbanization policy goal scenarios. The results showed that the novel model has spatial regional correlation in spatial region prediction. With the development of urbanization level, carbon emissions show a downward trend in more than 50% of cities from 2022 to 2025. In addition, the improvement of urbanization policy goals will promote the carbon peak time of most cities. The carbon emission intensity will exhibit an inverted U-shaped trend distribution in space. The research results are conducive to providing scientific guidance for the formulation of new-type urbanization policies and helping to achieve the dual carbon goals. • A multi-dimensional spatial disturbance grey model is proposed. • The novel grey model is consistent with the viewpoint of the First Law of Geography. • The spatial distribution of carbon intensity showed an inverted U-shaped pattern. [ABSTRACT FROM AUTHOR]

The environmental issues within the transport industry need to be given priority attention. Optimizing the transport structure and promoting low-carbon transport are essential measures for achieving carbon emission reduction. However, the rail-water multimodal transport scale is currently limited. The government has to intervene in the market through incentive policies, so how to expand the revenue of carriers and enhance the volume has become a major dilemma. Our paper constructs a transport system that includes road, water, and railway, and examines the impact of incentive policies on separate stakeholders. It is discovered that incentive policies can increase the revenue of carriers and simultaneously attract more shippers to elect rail-water multimodal transport. Subsidy policy can hasten the structural transformation of inland transport, making railway transport volume rise. Unfortunately, although the dry port policy may enhance the revenue of railway carriers, it leads to an apparent decline in the revenue of road-water multimodal transport participants. However, the subsidy policy can create a win-win scenario for multiple carriers while achieving carbon emission reduction, but to the detriment of social welfare. Additionally, the paper compares the interactions between diverse incentive policies and pivotal factors such as transport time. The conclusions of our research serve strategic recommendations for maximizing carriers revenues and provide support for government decision-making. • The impact of incentive policies on the rail-water multimodal transport is inspected. • Subsidy policy can make carriers better off, but may have adverse effects on social welfare. • Subsidy policy expands carrier volume and stimulates transport structure transformation. • Although dry port is conducive to social welfare, it hurts the revenue of carriers. • The dry port is beneficial for achieving long-distance carbon emissions reduction. [ABSTRACT FROM AUTHOR]

COVID-19 has represented a watershed in people's lifestyle. One important consequence has been the change in how people buy groceries online/offline that represent the most frequent shopping-related trip any household performs. Since this has substantially different transport and environmental implications, it is crucial to investigate what are the COVID-19-induced variations. This paper estimates both travel and environmental impacts grocery channel choice implies by comparing, in a diachronic fashion, the pre and during COVID-19 situation in Norway, considering alternative scenarios describing different service configurations for each channel considered. Stated preferences are used to estimate market shares for grocery purchase distinguishing between different channels: in-store, home delivery and click&pick. The robust comparative analysis between the two time periods is guaranteed by the use of the same methodological approach in the same geographical context. Results show that total emissions are lower during the pandemic and adopting a free delivery strategy not only increases home delivery market shares but also produces the lowest level of CO2 emissions regardless of COVID-19. The results obtained are particularly relevant in the "new normal" the world is experiencing both from a public policymaking perspective, when promoting transport-related interventions to curb emissions, and from a private standpoint, when customising market strategies to increase sales and profits. • COVID-19 has represented a watershed in people's lifestyle. • Investigating changes in how people buy groceries online/offline is important. • Stated preferences are used to estimate grocery market shares for different channels. • The paper estimates travel and environmental impacts pre and during COVID-19 via scenario analysis. • Results are particularly relevant for both the public and private sector in the "new normal" conditions. [ABSTRACT FROM AUTHOR]

Hydrogen is considered as a promising fuel in the 21st century due to zero tailpipe CO 2 emissions from hydrogen-powered vehicles. The use of hydrogen as fuel in vehicles can play an important role in decarbonising the transport sector and achieving net-zero emissions targets. However, there exist several issues related to hydrogen production, efficient hydrogen storage system and transport and refuelling infrastructure, where the current research is focussing on. This study critically reviews and analyses the recent technological advancements of hydrogen production, storage and distribution technologies along with their cost and associated greenhouse gas emissions. This paper also comprehensively discusses the hydrogen refuelling methods, identifies issues associated with fast refuelling and explores the control strategies. Additionally, it explains various standard protocols in relation to safe and efficient refuelling, analyses economic aspects and presents the recent technological advancements related to refuelling infrastructure. This study suggests that the production cost of hydrogen significantly varies from one technology to others. The current hydrogen production cost from fossil sources using the most established technologies were estimated at about $0.8–$3.5/kg H 2 , depending on the country of production. The underground storage technology exhibited the lowest storage cost, followed by compressed hydrogen and liquid hydrogen storage. The levelised cost of the refuelling station was reported to be about $1.5–$8/kg H 2 , depending on the station's capacity and country. Using portable refuelling stations were identified as a promising option in many countries for small fleet size low-to-medium duty vehicles. Following the current research progresses, this paper in the end identifies knowledge gaps and thereby presents future research directions. • Technological advancements of hydrogen production, storage and transport are reviewed. • Emissions and economic aspects of production, storage, transport and fuelling are analysed. • Refuelling protocols, temperature rise issue and its control strategies are discussed. • Recent progress of mobile hydrogen refueller is explored. • Challenges of hydrogen production to fuelling and future research directions are presented. [ABSTRACT FROM AUTHOR]

Recently, ammonia is getting more attractive as a potential alternative fuel for future power generation and transportation purposes due to its ability to reduce consumption of fossil fuels, soot, CO 2 emissions, and hydrocarbon pollutants. In the recent past, several studies aimed to the development of ammonia combustion systems have been conducted. However, ammonia combustion systems face several challenges, such as poor ignition timings, lower burning velocity, low energy density, shorter flammability limits than hydrocarbons. These issues are compounded by the significant increase in NOx emissions, which makes practical application of ammonia challenging. Various conventional methods, such as blending ammonia with other hydrocarbons and hydrogen, have been employed to improve combustion performance and reduce NO x emission. Meanwhile, it increased the engine complexities and at the same time, it raised CO 2 and NO x emissions. Recently, plasma-assisted combustion (PAC) has emerged as a promising technology to boost the ammonia combustion process by improving ignition delay timings, increasing flame speed, extending flammability limits, and reducing NO x emissions. In recent years, plasma-assisted combustion (PAC) has emerged as a promising technology to enhance the ammonia combustion process by improving ignition delay timings, increasing flame speed, extending flammability limits, and reducing NOx emissions. Nevertheless, only a few studies on plasma-assisted ammonia combustion (PAAC) are available in the literature. This review paper aims to summarize the latest advancements in the field of PAAC during the last years, including progress in the development of numerical models and experimental studies. The paper highlights the detailed procedure of PAAC numerical modeling and the limitations of numerical models. Finally, the latest numerical and experimental developments of PAAC have been discussed. • Ammonia is getting more attraction as an alternative fuel for future power and transportation sectors. • A comprehensive outlook of non-thermal plasma for ammonia combustion is provided. • The in-depth mechanisms of plasma assisted combustion are highlighted. • The latest numerical and experimental studies of Plasma assisted combustion were analyzed. [ABSTRACT FROM AUTHOR]

The ever-increasing challenges related to water security and climate mitigation underscore the pressing need for forward-thinking systems planning tools to drive urban sustainability transitions. In this study, we propose a novel city-level multi-objective planning framework that explores the nexus between carbon trading and water management, with the aim of facilitating water-efficient urban industrial restructuring. The framework integrates cap-and-trade mechanisms into a two-layered optimization model, creating an integrated approach to optimizing carbon emissions and generating economic opportunities for improving water efficiency. To illustrate the potential application of this framework, we conducted a case study focusing on Dongguan City, a water-stressed industrial metropolis in southern China. The results illustrate potential synergies between water planning strategies and carbon trading schemes, which could be harnessed to enable targeted reductions in water usage and carbon emissions. Furthermore, our findings identify the textile, apparel, and paper products manufacturing industries as primary candidates for strategic production scale reduction, emphasizing the importance of sustained support for the development of the computer and electronic manufacturing sector as a catalyst for urban sustainability transitions. By pioneering this new nexus-based perspective, our study offers valuable insights into long-term strategic planning for a low-carbon and resource-efficient urban economy. • Synergizing carbon trading and water management within a novel integrated planning framework. • Implementing resource-efficiency-driven optimization for water- and carbon-intensive manufacturing sectors. • Gaining insights into the specific roles of key manufacturing sectors in water management and carbon trading. • Introducing carbon trading systems may help in promoting water-efficient industrial restructuring. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • TGA analysis was performed for MSW components (food waste, paper, and plastics). • Solid residues of paper were 2 and 10 times higher than plastic and food. • Air/CO 2 reduced the burnout temperature by 300 ℃ for food waste than CO 2. • Combustion index (S) of MSW under Air/CO 2 was 4 times more than CO 2. • MSW reduced H f by 2.5 times than food waste, promising better combustion. This study examines the gasification kinetics of Brazilian municipal solid waste (MSW) and its components under air, CO 2, and air/CO 2 (70/30 vol%) atmospheres. The ignition indices of paper and plastic are 6 and 3 times that of food waste, which are 38.6 × 10−3 %/min3 and 19.6 × 10−3 %/min3, respectively, implying a faster separation of volatile compounds from the paper and plastic. The minimum E α values of 132 kJ/mol and 140 kJ/mol have been obtained for paper waste under air and air/CO 2 , respectively. On CO 2 condition, MSW has an average E a value of 96 kJ/mol. Under an air/CO 2 atmosphere, a high synergistic ΔW of −4.7 wt% has been identified between individual components. The presence of air and CO 2 improves the oxidation and char gasification process, thus resulting in better combustion. Hence, the gasification of MSW under an air/CO 2 atmosphere would improve the waste-to-energy plant's performance and minimize the CO 2 emission. [ABSTRACT FROM AUTHOR]

Maritime propulsion is recognized as a hard-to-abate sector and its decarbonization will therefore require transversal efforts, including the introduction of alternative fuels to reduce CO 2 emissions. Both ammonia and hydrogen could provide clean power; however, forecasts hint that ammonia will be especially useful for longer routes, while hydrogen suffers from low volumetric energy density. This paper evaluates the feasibility of a cargo ship with a SOFC powertrain equipped with LOHC-based hydrogen storage and compares the sizing and heat management requirements of four LOHC systems, namely N-ethylcarbazole (NEC), dibenzyltoluene (DBT), methylcyclohexane (MCH), decaline (DEC), with an ammonia-based one. The size of the 8.4 MW SOFC system is similar for the five carriers as expected. The dynamic performance of the LOHC system shows that the hydrogen flow rate can be effectively controlled by acting on the LOHC flow rate, reactor temperature, and pressure. However, LOHC systems are heavier (by a factor of 1.6 to 2.1) and larger (by 1.6 to 2.3 times) than ammonia systems. The decalin system results in the lowest mass and volume, while NEC is the heavier, and MCH is the least dense of the evaluated LOHCs. Similarly, the utilization of SOFC waste heat to cover dehydrogenation heat ranges from 45.6 % (NEC) to 27.9 % (ammonia). Overall, even considering the lower reaction temperature, LOHCs do not appear to be competitive with ammonia as hydrogen storage systems in the maritime sector. • Liquid organic hydrogen carrier (LOHC) systems discussed for maritime applications. • Different LOHC systems are sized, and the heat demand is evaluated. • Control strategies are devised to meet instantaneous hydrogen demand. • The dynamic response of LOHC-based systems is more than satisfactory. • Comparison with ammonia is unfavorable in terms of mass, volume and heat demand. [ABSTRACT FROM AUTHOR]

• We examine the role of circular economy and inclusive green growth in promoting energy transition and carbon neutrality in Europe. • We used three-pronged empirical strategy framed in advanced dynamic econometrics. • The results reveal that lagged of CO 2 emissions is a positive predictor of CO 2 emissions. • We show that embracing circular economy and inclusive green growth will be highly beneficial towards the attainment of carbon neutrality. • We recommend policy measures that considers both current and past emissions to promote environmental quality. This paper examines the role of the circular economy and inclusive green growth in promoting energy transition and carbon neutrality for several European countries during 2009–2021, using an advanced econometric strategy. To achieve this objective, we employed a three-pronged empirical strategy. The first strategy involved standard panel specifications, such as pooled ordinary least squares, Fixed Effects, Roger panel regression, white panel regression, and Driscoll–Kraay standard errors. The second strategy explored the long- and short-term dynamics of the relationships using the dynamic specifications of the Generalised Method of Moments, comprising the augmented Arellano–Bond, Ahn–Schmidt, Arellano–Bond, and Arellano–Bover/Blundell–Bond estimators. It further controls for endoegeneity using the Two stages Lease Square (2SLS and Lewbel 2SLS). The third strategy employed the Machado and Silva quantiles via moments to re-evaluate the heterogeneity drivers of carbon neutrality. Furthermore, an alternative and complementary strategy based on the statistical procedures of Hausman–Taylor and Feasible Generalized Least Squares was employed to verify robustness. The findings suggest that prior carbon emissions positively predict future emissions. Also, our results reveal that the adoption of a circular economy, including green growth and renewable energy, can significantly contribute to reducing carbon emissions. In contrast, domestic economic drivers, and eco-innovation increase carbon emissions. We propose that policymakers mandate producers to oversee the entirety of their product life cycles as a means to mitigate carbon emissions. Furthermore, endorsing training programs and educational initiatives aimed at cultivating the requisite skills for the energy transition and the adoption of circular economy practices is imperative for ensuring the realization of a successful low-carbon economy. [ABSTRACT FROM AUTHOR]

• E-waste has become a major environmental concern due to its increasing volume. • Socioeconomic and institutional factors are used to analyse the recycling of EEE. • Annual data from 2010 to 2018 were analysed in 20 EU countries by using a GMM. • GDP per capita, research & development and CO2 emissions decrease EEE recycling. • Education, environmental taxes, and waste collected drive the recycling rate of EEE. Moving from a linear to a circular economy is crucial to reduce environmental pressure. This transition is particularly relevant in the Electrical and Electronic Equipment (EEE) industry, given that EEE has one of the fastest-growing waste streams. Recycling is one solution for dealing with the growing amounts of this e-waste. Therefore, this paper analyses the drivers and barriers to e-waste recycling, taking into account the role of economic, social, institutional, and behavioural factors. Yearly data from 2010 to 2018 for 20 European Union countries were analysed employing an Arellano-Bond Generalised Method of Moments. The main findings were that, while environmental taxes and education boost the rate of e-recycling, economic growth and R&D appear to reduce it, and certain age groups are less likely to recycle e-waste. Recycling policies should prioritize education, environmental taxes, and addressing reluctance among the young and elderly to recycle. [ABSTRACT FROM AUTHOR]

The urgent development of economically practical and sustainable electrocatalysts to accelerate the hydrogen evolution reaction (HER) is critical for solving the pressing issues related to carbon dioxide emissions. Because of their platinum-like catalytic efficiency, excellent stability, and multidimensional structure of their crystal phases, molybdenum phosphides have emerged as extremely promising HER electrocatalysts. In this account, we begin with a meticulous explication of the hydrogen-generating process by water electrolysis, followed by an examination of the criteria used to assess HER catalytic activity. Also, the role of the phosphorus component and synthetic routes of molybdenum phosphides is presented in HER applications. Moreover, in recent years, various strategies designed to enhance the HER performance of molybdenum phosphides have been introduced, encompassing state-of-the-art techniques such as the fabrication of heterostructures, hetero-atom doping, hybrid structures involving carbon materials, and defect engineering. Furthermore, the theoretical studies based on density functional theory (DFT) are mentioned for HER. The paper concludes by emphasizing the current challenges and auspicious prospects in advancing electrocatalysts for hydrogen production, with a dedicated focus on catalysts based on molybdenum phosphides. • Outstanding features of molybdenum phosphides were presented. • Various methods were introduced in the fabrication of molybdenum phosphides. • Enhancement strategies in HER efficiency of molybdenum phosphides were discussed. • Current challenges and possible solutions on molybdenum phosphides-based HER electrocatalyst were provided. • DFT works of molybdenum phosphides on HER were presented. [ABSTRACT FROM AUTHOR]

The blending of hydrogen into natural gas can utilize existing natural gas pipeline infrastructure to achieve long-distance, large-scale, and cost-effective hydrogen transportation. However, the introduction of hydrogen poses a series of new technical and safety challenges to the operation of natural gas pipelines. Addressing these issues, this paper focuses on minimizing compressor station energy consumption and carbon emissions as objective functions, conducting a comprehensive analysis of station operation modes. Incorporating the characteristics of the model, the soft frost search strategy, the hard frost penetration mechanism, and the positive greedy selection mechanism are introduced to propose the IRIME algorithm. Comparisons are made with well-performing optimization algorithms using classical test functions to evaluate algorithm performance. To further validate the algorithm's accuracy, the West-East Gas Pipeline (Line 1) is considered, comparing the convergence speed and precision of the IRIME algorithm, leading to its selection for solving the model. Furthermore, consider analyzing the impact of different hydrogen blending ratios on the performance curves and operating points of compressors. Results indicate that compared to conditions without hydrogen blending, the compressor outlet temperature and pressure drop increase for hydrogen blending ratios of 5%, 10%, 15%, and 20%; as the hydrogen blending ratio increases, the efficiency of fuel-driven compressors, efficiency of electrically driven compressors, and average efficiency of compressor units decrease; with an increase in hydrogen blending ratio, carbon emissions from fuel-driven compressors and electric-driven compressors both decrease. In conclusion, with an increasing hydrogen blending ratio, total energy consumption increases by 3.14%, 5.69%, 8.68%, and 10.90%, while total carbon emissions decrease by 2.99%, 5.36%, 8.32%, and 10.68%. These findings provide valuable insights for operational guidance in the field. • Establish an optimization model for energy consumption and carbon emissions in hydrogen-blended natural gas pipelines. • Analyze the effects of varying hydrogen blending ratios on compressor performance curves and operational points. • Introduce the RIME algorithm, validate its speed and precision, test it on the West-East Gas Pipeline (Line 1). [ABSTRACT FROM AUTHOR]

As a promising strategy to mitigate carbon emissions, hydrogen enrichment of conventional fuels is gaining increasing interest, but can lead to increased propensity to damaging thermoacoustic instability. This paper demonstrates the ability of machine learning algorithms to reliably predict a key flame behavior relevant to thermoacoustic stability prediction – the flame's nonlinear response to upstream acoustic forcing. Using computational simulations of a laminar premixed flame under difference hydrogen enrichment and equivalence ratio conditions, training data for machine learning are generated. The machine learning models are then used to predict the flame response under new test conditions, including extrapolating into new hydrogen enrichment regimes. The effect of algorithm choice, data structure, data size, and extrapolation distance on the performance of different machine learning models is investigated with particular attention to performance with sparse training data. It is found that a type of neural network known as the multi-layer perceptron (MLP) model outperforms the Gaussian process and random forest models in both interpolation and extrapolation tasks. A physics-informed preprocessing strategy, involving extracting the time delay of the flame response (which can be deduced from geometry and flow parameters) prior to applying machine learning, is found to remarkably improve the accuracy of machine learning models, especially in extrapolation tasks. When the extrapolation into new hydrogen content levels is strong enough, the MLP model no longer performs well. However, for small and intermediate extrapolation, the MLP model shows a commendable level of prediction, even with small data sets, fulfilling needs relevant to thermoacoustic stability prediction. Extending the MLP model to experimental data from turbulent flames, the gain fall-off frequency and phase lag are accurately predicted but not the secondary periodic fluctuations in gain. • AI-assisted prediction of flame response in new hydrogen enrichment regimes. • A physics-informed strategy extracting the time delay improves model performance. • The effects of algorithm choice, data structure and data size are studied. • MLP model shows good predictions in small extrapolation tasks with sparse data. • Extending to turbulent flames, the MLP model captures fall-off frequency in gain. [ABSTRACT FROM AUTHOR]

In order to guide the operation of the actual cascade system, this paper takes the cascade system as the research object and compares the use of six refrigerant pairs. Unlike the previous single-objective optimization of refrigeration system carbon emissions and other indicators, this research uses a multi-objective optimization algorithm, that is, we consider the cascade system's exergy efficiency and carbon emissions at the same time. We reduce carbon emissions while improving the system's exergy efficiency, and finally find out the specific operating conditions under which the system can realize low-carbon and high-efficiency operation, which further promotes the process of achieving energy saving and emission reduction in factories. The optimization results show that among the six refrigerant pairs, the use of R744-R134a and R744-R290 refrigerant pairs can make the system operate better, but considering the high global warming potential (GWP) of R134a refrigerant, the use of R744-R290 combination is more recommended. [Display omitted] [ABSTRACT FROM AUTHOR]

Solar energy absorption and storage of integrated ceramic materials is both the absorption of sunlight and storage of sunlight into thermal energy functional materials. In this paper, the effect of Fe 2 O 3 on the solar absorptivity, thermal storage properties, sintering temperature, and physical properties of mullite-based thermal storage ceramics was investigated. The results show that the absorptivity and thermal storage density of the sample AF4 (Bauxite:50 wt%, Clay:50 wt%, Fe 2 O 3 :11 wt%) after sintering at 1420 °C are 87.2% and 1116.5 kJ kg−1, respectively; and the unit volume of the AF4 sample can provide the power grid with 918.01 kW h of electricity, save 112.91 kg of coal, and reduce 361.33 kg of CO 2 emission. This study systematically elucidated the mechanism of the enhancement of sample absorption caused by Fe3+ doping-induced changes in substrate color, reduction in material forbidden bandwidth, and lattice anharmonic vibration effect, in addition to comprehensively evaluating the feasibility of the optimal AF4 sample for use in solar energy absorbing and storing integrated ceramic materials. [ABSTRACT FROM AUTHOR]

The current study examines a novel multigeneration plant that uses geothermal energy to produce clean and sustainable products. The process includes a re-compression supercritical Brayton power plant (re-sBC), an ejector cooling unit (EJCS), a humidifier dehumidifier desalination (HDH) unit, a Proton-Exchange Membrane (PEM) process, and a hot water preparation unit. The designed plant is able to generate hot water, cooling, power, hydrogen, and freshwater using the geothermal source. In the current paper, the thermodynamic analysis, CO 2 emission assessment, and exergoenvironmental index evaluation are executed to determine the system efficiency and the association between the system and the environment. A thorough parametric examination is fulfilled, to show how the system indicators impact efficiency and generated products. According to analysis data, the proposed multigeneration plant is able to generate 1278 kW of heating load, 229.6 kW of refrigeration capacity, and 109.5 kW of net power rate. Additionally, the capacity of the freshwater is 0.1188 kgs − 1 and the hydrogen is 0.001317 kgs − 1 . This developed system emits a total of 117 tonnes of CO 2 emissions per year for these useful outputs. In conclusion, the energetic and exergetic performance of the suggested MG plant are 14.09 % and 23.35 %, respectively. • A sustainable geothermal energy-based MG is proposed. • The thermodynamic, emission, and environmental analysis is conducted. • Design and evaluation of the Green hydrogen production and storage. • Re-compressed sBC integrated into geothermal driven MG plant. • Total energy and exergy efficiency is computed as 14.09 % and 23.35 %, respectively. [ABSTRACT FROM AUTHOR]

Ports are essential and strategic nodes of international trade and economic activities. The integration of port resources helps enhance the optimal division of port functions to further promote economic development. This paper explores the evolutionary trends of port integration policy from 2011 to 2021 in China through a text-mining approach. We first used the Latent Dirichlet Allocation (LDA) topic analysis method to analyze the port integration policies and summarize the evolutionary trends of port policies. In addition, an association analysis was conducted to explore port integration policies' impacts by examining their relationships among the environmental protection, digitalization level, and port development scale. Our findings suggested that China's port integration policy has evolved from specific and simple to abstract and complicated at the managerial level. Port development has enriched from infrastructure construction to the ideology of economic development. Our findings show that China's port integration is gradually improving the port operation. The findings of the study contribute to the extant literature by analyzing the port integration policy evolution in China and can be referred to by other countries. • Text mining method was used to explore the port integration policy evolution. • Port integration policy evolved from specific and simple to abstract and complicated. • Port development enriched from basic infrastructure to the governance model. • The evolution of port integration policy was related to reducing carbon emissions in the port sector. • The evolution of port integration policy made the ports intelligent in association with digital technology such as big data and AI. [ABSTRACT FROM AUTHOR]

Hydrogen is crucial in the forthcoming low-carbon energy systems offering the potential to reduce CO 2 emissions and its versatility to be utilized across diverse energy sectors. Precise assessment of hydrogen thermo-physical characteristics is vital for the effective design and execution of numerous processes encompassing hydrogen production, transportation, storage, and utilization. In this paper, various distinct machine learning (ML) approaches, namely extreme gradient boosting (XGBoost), Random Forest (RF), Adaptive boosting (AdaBoost), and Light gradient boosting machine (LightGBM) were implemented to estimate thermo-physical properties, namely thermal conductivity, density, viscosity, and diffusivity in water based on pressure and temperature variables. For this purpose, comprehensive experimental data points covering a broad range of pressures and temperatures were acquired from the literature. The results demonstrated a strong agreement between the predictions generated by all proposed techniques and the experimental data. Furthermore, XGBoost yielded a root mean square error (RMSE) of 0.0085, 2.1548, 0.3343, and 1.5308 for the estimation of thermal conductivity, density, viscosity, and diffusivity, respectively, demonstrating superior accuracy in predicting all outcomes. In the sensitivity evaluation, it was observed that temperature, with absolute relevancy factor 0.88, 0.54, 0.246, and 0.92 had the most significant influence on the hydrogen thermo-physical properties in the order mentioned above. Furthermore, the trend analysis of the model indicated that all thermo-physical properties of hydrogen experience positive effects from temperature and pressure, except for density, which decreases as temperature increases. The leverage technique confirmed the statistical validity of both the experimental dataset used for modeling and the model's development. This study's results provide the efficient design and secure operation of hydrogen storage, refueling stations, transportation infrastructure, and production facilities. [Display omitted] • Hydrogen holds great importance in the forthcoming low-carbon energy. • XGBoost, RF, AdaBoost, and LightGBM are utilized for modeling the thermo-physical properties of hydrogen. • XGBoost demonstrates its superior accuracy in predicting thermal conductivity, density, viscosity, and diffusivity. • Temperature has the most significant influence on the hydrogen thermo-physical properties. [ABSTRACT FROM AUTHOR]

Excessive NO x and CO 2 emissions pose a significant challenge in the clean combustion of natural gas, which is expected to be solved through the combination of exhaust gas recirculation and hydrogen enrichment. In this study, the pollutant emission and temperature distribution of a laminar diffusion flame during the combustion of CH 4 mixed with CO 2 /N 2 /H 2 are experimentally investigated. The NO emission reduction effect of CO 2 dilution on hydrogen-enriched methane is evaluated as well. The experimental results show that CO 2 dilution has a deeper NO emission reduction and flame temperature attenuation than N 2 dilution. At a given blending ratio of 50%, CO 2 dilution effectively reduces NO emissions by approximately 50%, whereas N 2 dilution decreases NO emissions by about 10%. Compared with N 2 dilution, the peak flame temperatures of CO 2 dilution cases are reduced by 15.3 K, 45.1 K, 31.7 K, 32.6 K, and 44.3 K, respectively, when the blending ratios increase from 10% to 50% with an interval of 10%. The difference caused by the CO 2 /N 2 dilutions between the inhibition effect from the inherent attributes and the enhanced mixing effect on the flame temperature, results in a significant peak temperature gap of 45.1 K at a 20% blending ratio. H 2 enrichment enhances the flame temperature and promotes the combustion reaction process, resulting in a more compact flame structure. NO emission factors for H 2 blending ratio of 0% and 50% are 1953 mg·(kg Fuel)−1 to 2544 mg (kg Fuel)−1, respectively, which is due to the excessive NO generation because of the temperature rise in the combustion zone. CO 2 dilution demonstrates an excellent NO emission reduction effect on hydrogen-enriched methane gas. This paper may provide some references for the development and application of exhaust gas recirculation and hydrogen enrichment. • The combustion characteristics of CH 4 mixed with CO 2 /N 2 /H 2 are investigated. • CO 2 is better than N 2 in NO emissions reduction and flame temperature attenuation. • H 2 enrichment increases the NO emissions and decreases the CO emissions. • H 2 enrichment increases the flame temperature and promotes combustion reaction. • CO 2 shows an excellent NO emissions reduction for hydrogen-enriched methane. [ABSTRACT FROM AUTHOR]

[Display omitted] • Glass fiber wind turbine blades (WTBs) can provide raw material to produce cement. • Glass fiber WTBs can serve as fuel and replace coal to produce cement. • High boron in some glass fiber WTBs might limit replacement rates. • Combustion of fossil-fuel polymer in WTBs can slightly reduce plant CO 2 emissions. • Glass fiber wind turbine blades are compatible with the cement production process. The objective of this paper is to evaluate the feasibility of co-processing wind turbine blade (WTB) material in cement manufacturing to provide an end-of-life means to divert the solid waste of decommissioned WTBs from landfills. Many WTBs consist primarily of glass fiber reinforced thermoset polymers that are difficult to recover or recycle. Portland cement is produced world-wide in large quantities, requiring immense quantities of raw materials (mostly calcium oxide and silicon oxide) and kiln temperatures approaching 1,450 °C. This work contributes analyses of WTB material composition, and predicts the energy provided through the combustible components of the WTBs and raw material contributions provided by incorporating the incombustible components of the WTBs to produce cement. Approximately 40 to 50 % of the WTB material will contribute as fuel to cement production, and approximately 50 to 60 % of the WTB material is expected to be incombustible. One tonne of WTB material can displace approximately 0.4 to 0.5 tonne of coal, while also contributing approximately 0.1 tonne of calcium oxide and 0.3 tonne of silicon oxide as raw material to the cement production process. The glass fiber WTB tested had an average boron content of 4.5 % in the ash. The effects of this high boron content on the cement and its production process should be evaluated. Co-processing WTBs in cement plants will slightly reduce combustion-related CO 2 emissions due to avoided calcination. It seems feasible to co-process glass-fiber reinforced WTBs in cement production as WTBs provide suitable raw materials and compatible fuel for this process. [ABSTRACT FROM AUTHOR]

Pollution reduction and low-carbon development are two specific but intertwined goals of addressing climate change and sustainable development of the United Nations in 2030, and the effective use of digital financial inclusion is imperative for driving technical innovation, upgrading industrial structure, and addressing climate change. Therefore, this paper investigates the impact of digital financial inclusion on the coupling coordination between pollution reduction and low-carbon development using a panel dataset of 30 China's provinces from 2011 to 2020. The results show that the coupling coordination between pollution reduction and low-carbon development in China improves significantly during the sample period. The synergistic effect of different economic zones and provinces varies greatly in space and time. In addition, digital financial inclusion has a promoting effect on the coupling coordination of pollution and carbon emission reduction. A mechanism analysis also reveals that technological innovation, industrial structure and energy consumption are the core transmission channels through which digital financial inclusion influences the synergistic effect of pollution and carbon emission reduction. This suggests that the need of coordinated governance by policymakers is warranted, and digital financial inclusion is an important way to this coordinated governance. [ABSTRACT FROM AUTHOR]

The Chinese government aims to balance employment stabilization and emissions reduction when it initiates an emissions trading scheme (ETS) to control carbon emissions. However, the policymakers should not neglect the role of imperfectly competitive market structure and market power from incumbent firms. In view of this, classical framework of Berman and Bui's (2001) is extended in this paper to clarify the theoretical mechanism of employment effect of the ETS considering firm-level market power. In addition, based on the firm-level panel data from 2008 to 2019 of China, the employment effect of each pilot ETS is measured with the method of difference-in-difference-in-differences. Then a moderating effect model is established to verify the role of firm-level market power on the heterogeneous employment effect among the pilot ETSs. Moreover, the employment effect is further decomposed to evaluate the influential mechanism from the perspective of firms' strategic behavior. It is found that there is negative employment effect of China's ETS policy, due to the significant moderating role of firm-level market power. This decrease in labor demand is mainly dominated by a negative output effect rather than a positive substitution effect because strategic allowance sellers with stronger market power tend to hire fewer employees to reduce carbon emissions by controlling production scale. However, the heterogeneity of policy effects resulted by market structure is also identified in different pilot regions. Employment dividend has been found in Beijing and Tianjin where strategic allowance buyers manipulate the carbon market and hire more employees to consolidate their market power. Therefore, policymakers should improve the design of the ETS to overcome the adverse employment effect duo to the region-specific market structure. [ABSTRACT FROM AUTHOR]

Fossil-based natural resources are carbon-intensive, and over-reliance on them often leads to persistent high carbon emissions at national or regional levels, resulting in the carbon curse. Based on the panel data of 114 resource-based cities in China from 2007 to 2020, this paper examines the carbon curse and solutions for these cities from the perspectives of total and intensity of carbon emissions. The results show that: Firstly, due to the different stages of urban development, resource endowment, degree of resource dependence, and policy background, there is a heterogeneity of carbon curse in China's resource-based cities. Secondly, the carbon emission trading policy can effectively mitigate the carbon curse in China's resource-based cities, and the robustness tests demonstrate the validity of this finding. Thirdly, under the carbon emission trading policy, industrial structure upgrading and digital transformation can play a secondary moderating role in resolving the carbon curse in resource-based cities, further strengthening the inhibitory effect of the carbon emission trading scheme on the carbon curse. In contrast, green technology innovation exhibits no enhancement in the impact of the policy. These findings contribute to the existing research on the carbon curse, offering valuable insights and policy implications for effectively addressing this challenge. [ABSTRACT FROM AUTHOR]

How to improve carbon emission efficiency (CEE) to achieve sustainable economic development has triggered contemplation among society and policy-makers. Previous studies have confirmed that e-commerce development can reduce local carbon emissions, but the impact of e-commerce development on CEE is unclear. This paper investigates the impact of e-commerce development on CEE and its spatial spillover effect using Chinese city-level panel data, taking the National E-commerce Demonstration City (NEDC) policy as a quasi-natural experiment. Results show that the NEDC policy significantly improves local CEE by promoting industrial structure upgrading, green technology innovation, and improving energy efficiency. The influence is more pronounced in regions with inadequate information infrastructure, unfavorable business environment, and limited marketization. However, the NEDC policy has a negative spatial spillover effect, reducing surrounding cities' CEE. The findings unveil the complicated impact of e-commerce development on CEE and offer policy implications for improving inter-regional carbon reduction synergy and low-carbon economic transformation. [ABSTRACT FROM AUTHOR]

• Carbon emissions trading, industrial structure upgrading and green development are integrated into a unified analytical framework. • Taking the carbon trading mechanism as the moderating variable can effectively combine the method of comparative static analysis. • Whether in the long term or the short term, the carbon pilot policy and the industrial structure upgrading policy implemented at the same time will have excess benefits. • When factor flow between cities is considered, excess benefits still exist significantly. Clarifying the influence mechanisms of carbon emissions trading scheme (ETS), industrial structure upgrading (ISU), and green development is of great theoretical and practical significance. Existing studies have only focused on the role of ETS or ISU on green development and have not included them in an analytical framework. The DID model and the moderating effect model are therefore combined in this work to to explore how the ETS will affect the link between ISU and green development throughout the period of 2008 to 2019 using panel data from 271 Chinese cities. Through a series of robustness and endogeneity tests, we find that: (1) ETS can significantly moderate the U-shaped relationship between ISU and green development, and this impact is significant in both the long and short term; (2) When ETS and ISU are implemented at the same time, the effect of the combined actions is greater than the sum of the effects of the two policies implemented separately, which means that the combined actions has excess dividends; (3) ETS and ISU have significant direct effects and spatial spillover effects on green development, and the excess dividends of combined actions also exist significantly at the spatial level. The research results of this paper provide an important theoretical and empirical basis for establishing the combined actions of ETS and ISU. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper proposes a multi-objective framework for sustainable scheduling of hybrid hydrogen-power systems. In the proposed model, the microgrid system incorporated renewable energy systems, battery energy storage systems, non-renewable resources, power-to-hydrogen, hydrogen-to-power, demand response programs, and hydrogen storage systems to present a highly flexible structure in the energy systems. The purpose of the proposed model is to provide a complete operation mechanism for the daily scheduling of microgrids considering environmental, economic, and sustainable problems. To this end, a stochastic three-objective optimization model is proposed to consider the intermittent behavior of renewable generation, loads, and market prices and simultaneously tries to minimize the carbon emission, total cost, and peak loads. The peak load reduction is important because it increases the reliability, renewable energy integration, power quality, and reduced cost of reserve capacity. Therefore, a min-max approach is presented to reduce the peak load in the proposed model. Also, the hydrogen-to-power and power-to-hydrogen resources are integrated as flexible resources to increase the efficiency of microgrids during operation scheduling. The proposed model is evaluated on a standard case study and the numerical results show the multi-objective model reduces the carbon emission by 28.05 kg and increases the load factor by 6.26%, respectively. • Description of a multi-objective problem that integrates electricity and hydrogen. • Proposing an enviro-economic model to reduce carbon emission and operating cost. • The proposed model significantly uniforms the load profile by min-max approach. • Hydrogen storage tank and DR programs are considered to increase the flexibility. [ABSTRACT FROM AUTHOR]

Hydrogen energy is recognized as a crucial solution for addressing energy crises and advancing energy conservation and emissions reduction. It will play a significant role in the future integrated energy systems (IESs). However, the influence of seasonal variations in scheduling optimization of hydrogen-integrated energy system has rarely been investigated. A low-carbon scheduling model for IES, adopting multiple demand responses and a ladder-type carbon trading mechanism, has been established. Additionally, a multi-time scale dispatch optimization strategy considering seasonal hydrogen utilization is thus proposed in this paper. Specifically, day-ahead scheduling optimizes the system taking into account the seasonal variations of renewable energy and load. In the intraday stage, rolling optimization is adopted to address the forecasting errors introduced by wind and photovoltaic fluctuations. In the real-time stage, chance-constrained methods are employed to ensure short-term supply-demand balance. The efficacy of the proposed strategy is verified using real-world measurements, and the results show the multi-time scale scheduling strategy and multiple demand responses effectively enhanced the system's self-regulation capability, leading to a 12% increase in renewable energy absorption. In addition, seasonal hydrogen utilization is essential for system design, as it enhances the absorption of renewable energy, reducing the purchase cost by 4% and the total cost by 2.6%. • Integrated energy system considering seasonal hydrogen utilization. • Multi-time scale optimization with multiple demand response. • Ladder-type carbon trading mechanism reduces system carbon emissions. • Refined hydrogen utilization increased renewable energy absorption by 12%. [ABSTRACT FROM AUTHOR]

This paper presents the preliminary design and thermodynamic analysis of hydropower and solar integrated e-fuel production system for a tea factory. In this regard, an integrated hydro-solar e-fuel production system has been developed, which is mainly able to produce e-methanol and green hydrogen. The system contains five main subsystems: i) Proton exchange membrane electrolyzer system, ii) CO 2 capture and storage system, iii) Methanol production system, iv) Photovoltaic system, and v) Penstock hydroelectric power plant. In terms of the general system operating principle, it is important to emphasize that the energy need of the system is supplied by solar power plant during the sunshine duration (the case 1) and provided by hydropower plant in the period when solar energy is not sufficient (the case 2). Considering the required assumptions, in the first step, preliminary design was performed, and in the second step, the energy and exergy analyzes were achieved, and in the final step, the effects of parameters such as CO 2 capture efficiency, methanol reactor conversion ratio, and environmental temperature on the system performance were parametrically investigated. Accordingly, in the case 1, the maximum energy and exergy efficiencies of the integrated e-fuel production system were respectively obtained to be 7.132% and 6.569% while, in the case 2, those were respectively calculated to be 39.44% and 42.36%. Moreover, approximately 235.9 tons of CO 2 emission in operation period of the tea factory considered in this work can be reduced by the integrated hydro-solar e-fuel production system that has a production capacity of 399.8 kg/h for methanol and 37.73 kg/h for hydrogen. It is expected that the integrated system concept may contribute to the researchers, system designers, policy makers, investors, and different enterprises for practical applications. • Hydropower and solar integrated e-fuel production system for a tea factory is proposed. • The preliminary design and thermodynamic analysis have been performed. • Thanks to the developed systems, 235.9 tons of CO 2 emissions can be reduced. • The maximum exergy efficiency of case-1 and case-2 are obtained to be 6.569% and 42.36%, respectively. [ABSTRACT FROM AUTHOR]

This research stems from the urgent need to address the complex challenges faced in multimodal transportation within the cargo sector, particularly concerning the reduction of transportation costs and CO 2 emissions. Existing transportation systems often struggle to efficiently balance economic and environmental concerns, necessitating innovative solutions. In this paper, we have introduced a novel mathematical model that integrates Singular Value Decomposition (SVD), Genetic Algorithms (GA), and the Adaptive Neural Fuzzy Inference System (ANFIS). The synergy of GA and the ANFIS forms a dynamic learning system that continually refines solutions by adapting to historical decisions and aligning with supply-demand dynamics. This integrated approach aims to optimize cost allocation and resource utilization while simultaneously minimizing CO 2 emissions. Deploying the ANFIS+GA+SVD model in multimodal scenarios yields impressive results, with a minimal average percentage error (MAPE) of 0.28% for transportation costs and a remarkable coefficient of determination R2 of 0.992 for the Truck + Ship scenario. Similarly, a MAPE of 0.11% for CO 2 emissions, supported by an impressive R2 of 0.989, underscores the model's accuracy. Observations of people's transportation choices in response to emission price changes reveal a significant decrease in truck usage, plummeting from 84% to below 50%. Alternative transportation methods, especially in the 3S-3 M-3 C scenario, show a substantial surge, with railways leading at a remarkable 30% increase in utilization. The combined quantity and cost comparison, utilizing the ANFIS+GA+SVD model, emphasizes the suitability of the Truck + Ship scenario for Iraq's transportation network, reinforcing the case for sustainable and efficient multimodal transportation systems. [ABSTRACT FROM AUTHOR]

Green hydrogen has become more attractive as a fuel for engines to reduce greenhouse gas emissions. By mixing it with natural gas (NG), the modification work on the engine can be minimized but the carbon dioxide emissions from combustion can still be decreased. In this paper, an experimental study was accomplished to investigate the performance of a spark-ignition engine fueled with hydrogen-natural gas blends by either keeping a constant ignition timing or changing it. Up to 25 mol-% hydrogen was mixed into natural gases with different compositions and the methane number and Wobbe index were calculated and compared to the requirements set by Euromot. The results show that up to 15 mol-% hydrogen can be blended into NG to meet the limits of Euromot. However, when 25 mol-% hydrogen was mixed into NG the methane number varied between 56 and 64 depending on the gas composition. This would most likely cause knock for a mixture consisting of higher hydrocarbons but during the executed tests knock was never a problem. Furthermore, it was detected that the methane number alone cannot tell the knock tendency of a gas in a certain engine and an additional condition is needed such as the hydrogen level. An adjusted ignition timing was also preferable compared to a constant one to keep the engine component temperature at a moderate level. • A SI-engine was fueled with different hydrogen-natural gas (H 2 -NG) mixtures. • Wobbe index and methane number (MN) were calculated for all test points. • Efficiency was improved and emissions were decreased with higher hydrogen content. • No tendency of knock when 25 mol-% hydrogen was mixed into natural gas with a low MN. • Additional condition is needed for MN eg. H 2 -level to be sure if knock can happen. [ABSTRACT FROM AUTHOR]

In continuation of the previous part, this paper comprehensively focuses on energy, exergy, exergo-economic, and environmental (4E) analyses of two prioritized clean hydrogen (H 2) supply chains pathways. The first scenario relies on domestic demand , involves blue H 2 production and storage using steam methane reforming coupled with carbon capture and storage through H 2 conversion to hydrogen carriers in liquid form (ammonia and methanol) aligned with the existing infrastructure. The second scenario involves green H 2 production from photovoltaic panels as the power source follows by storing H 2 in liquid form which is more suitable to export. The findings indicate that the blue H 2 system outperforms the green H 2 system in terms of energy and exergy, boasting 41.38% and 22.15% compared to 12.16% and 12.75%, respectively. However, when examining economic parameters, the blue H 2 system shows a total cost rate of 1976 US$/h, a net profit of $747.2 million (mn) at the end of its lifetime, and a payback period of approximately nine years. Conversely, the green H 2 system demonstrates economic indicators of a 125.2 $/h as a total cost rate, $1.26 billion (bn) net profit, and an 8.17 year payback period. Moreover, the production cost rates for blue and green H 2 are 1.32 $/kg and 2.55 $/kg, respectively; while the CO 2 emissions rate in the blue H 2 system is 10.71 kg/s. The green H 2 system prevents 19.84 kg/s of CO 2 emissions resulted a significant environmental cost reduction of 2.28 $/kg H 2. This analysis facilitates a thorough comparison of these two clean H 2 production and storage systems, offering insights for policymakers across performance, economic, and environmental dimensions. • A comprehensive 4E analysis was applied for the selected H 2 value chain scenarios. • Blue H 2 scenario is superior economically while environmentally the green one takes precedence. • Carbon credit makes the green H 2 scenario emerges frontrunner utilizing PV solar technology. • Methanol was recognized as the most cost-effective H 2 carrier for storage in Iran. [ABSTRACT FROM AUTHOR]

Combustion of hydrogen-enriched natural gas is a valuable short-term strategy for reducing CO 2 emissions from high temperature industrial heating. This paper presents several experiments on combustion characteristics and the formation of nitrogen oxides. The experiments included hydrogen contents up to 100% and fuel heat inputs up to 75 kW. Water-cooled lances were used to influence the furnace temperature. The analysis includes the distribution of furnace temperatures, the composition of flue gas, the cooling capacity of the lances under steady-state operating conditions, and OH*-chemiluminescence imaging of the near burner region. The presented results demonstrate the dependence of furnace conditions and NO X formation on various factors, such as different air inlet fluxes, furnace temperature, and fuel composition, for constant heat inputs. Efficiency increased by up to 5.5% and significant changes in flame shaped along with a maximum increase in NO X emissions when comparing natural gas to hydrogen was measured at 167%. [Display omitted] • Combustion of hydrogen-enriched natural gas with 0 to 100% H 2 • Experimental analysis of an industrial burner in a steady state, false air-free furnace. • Converged measurements for temperature, flue gas composition and cooling heat fluxes. • Dependence of NO X in mg/kWh on flame shape, temperature, fuel blend and air ratio. • Imaging of self-emitted OH*-chemiluminescence from turbulent jet flames. [ABSTRACT FROM AUTHOR]

Business-as-usual (BAU) cement production is associated with a linear model that contributes significantly to global warming and is dependent on volatile energy markets. A novel circular model is proposed, by adding three power-to-gas system components to current production systems: a calcium-looping (CaL) CO 2 capture unit; water electrolysis for hydrogen and oxygen generation; and a methanation unit for synthetic natural gas (SNG) production. The paper presents the first analysis of the combined industrial-scale operation of these components in a closed loop, where the SNG fuels the cement kiln and the CaL unit, while the O 2 produced feeds it. The circular, hybrid, and BAU models are compared in three feasibility scenarios. It is concluded that the circular model outperforms the other alternatives environmentally, opening a potential pathway for the cement industry to achieve near net-zero CO 2 emissions, reduce energy dependence and improve economic efficiency. [Display omitted] • Innovative circular model proposed for carbon-neutral cement production. • Novel integration of CaL CO 2 capture, water electrolysis and methanation units. • Comparative techno-economic and environmental analysis conducted. • Circular model outperformed current and hybrid models. • Near net-zero CO 2 emissions and increased energy independence achieved. [ABSTRACT FROM AUTHOR]

This paper presents research performed on set-based multi-criteria optimization for the preliminary design of slab frame bridges. As a result of immense CO2 emissions emerging from concrete production, there is a need for optimization methods decreasing the volume of concrete without affecting the function of the structure. Previous research suggests a general correlation between CO2 footprint- and cost reduction, due to minimized material use. However, the aspect of buildability may conflict with lessened material, as optimized designs might simultaneously be less buildable. This research aimed to develop an optimization method with respect to the investment cost and environmental impact while also considering buildability cost aspects. The optimization algorithm shows the possibilities of reducing the environmental impact by up to 13.7% for a slightly increased cost of 2.3%. Thus, by implementing optimization procedures in the early stages of the planning process the holistic cost effects related to green solutions can be presented, favoring the choice of sustainable designs amongst clients during tendering procedures. [ABSTRACT FROM AUTHOR]

The transition to sustainable and low-carbon ironmaking processes has necessitated innovative solutions. The most prominent solutions are the establishment of a circular economy by recirculating the iron-rich residues from steelworks and the adoption of hydrogen as a clean reducing agent to mitigate fossil CO 2 emission. One such residue is mill scale, which is generated during steelmaking, casting, and rolling processes. However, the fine particles and easy reoxidation of the mill scale make it difficult to be used directly in iron and steel production without proper compaction. This paper aims to demonstrate the feasibility of mill scale briquetting using organic binders to meet the requirements of hydrogen-based direct reduction. The study will investigate the influence of binder type, binder dosage, moisture content, and compaction pressure on the briquetting process and the briquettes quality. Moreover, the reducibility of optimized briquettes will be examined by hydrogen at 900 °C using a thermogravimetric analyzer coupled with a quadrupole mass spectroscopy (TGA-QMS). The optimal combination for achieving the best mechanical strength and reducibility was a briquette produced with 1% Alcotac® CB6, 1% KemPel, and 2.5% moisture content, compressed at a pressure of 125 kN. • Circular economy is a prominent solution for sustainable ironmaking. • Hydrogen is the way forward to decarbonize the steel industry. • Briquetting of mill scale is a way for its successful recirculation. • Organic binders can successfully be implemented in ironmaking. • Briquette compaction and moisture significantly influences its strength. [ABSTRACT FROM AUTHOR]

In September 2020, the European Union (EU) decided to include the maritime industry into the EU emissions trading system to effectively control carbon emissions from ships, namely the maritime emissions trading system (METS). Various allocation and trading schemes are adopted in practice. This paper investigates a comparison of allocation and trading schemes of the METS from the perspective of liner shipping carriers and regulators, respectively. We explore how to determine the optimal allocation and trading scheme of the METS and how the liner shipping route (LSR) choice decision (following or avoiding the METS) and carbon emissions will be affected. For liner shipping carriers, we use a mixed-integer linear programming model that aims to reduce carriers' costs to formulate our problem. For regulators, we present a bi-level programming model that aims to reduce carbon emissions. In numerical experiments, we further analyze the impact of joining the METS on the scheme choice, LSR choice and emissions by considering the European Economic Area and the Red Sea being covered by the METS. Numerical experiments are provided to show the effectiveness of our proposed models. • Investigate allocation and trading schemes of the maritime emission trading system. • Propose a liner shipping route choice problem. • Develop a mixed-integer linear programming model. [ABSTRACT FROM AUTHOR]

The construction industry's heavy reliance on conventional cement production contributes significantly to global carbon dioxide emissions, prompting the need for eco-friendly building materials. Geopolymers, synthesized from natural materials like clay and fly ash, offer a sustainable alternative to traditional cement. This paper investigates the development of phosphoric acid-activated geopolymers with sanitary ware waste (SWW) as aggregates, aiming to create high-performance, environmentally friendly building materials. Various particle sizes of SWW were incorporated into the geopolymer matrix, revealing a strong relationship between particle size and compressive strength. The inclusion of SWW improved compressive strength, with a notable 83 % increase at 30 % SWW content. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses highlighted the formation of new bonds in the geopolymeric gel, while scanning electron microscopy (SEM) showed microcracks and good adhesion between SWW particles and the geopolymer matrix. Thermal resistance tests demonstrated that SWW-reinforced geopolymers exhibited improved resistance to high temperatures compared to the reference geopolymer. XRD analysis of thermally treated geopolymers revealed the transformation of amorphous phases into stable crystalline phases. SEM/EDX mapping confirmed the presence of silica-rich phases, contributing to the materials' mechanical properties and thermal resistance. This study underscores the potential of SWW-based geopolymers as sustainable, high-performance building materials. [ABSTRACT FROM AUTHOR]

This paper endeavors to utilize the numerical modeling method to evaluate the energy, economic, and environmental performances of a new hybrid PV-FC system for green hydrogen and electricity production. The proposed system consists of photovoltaic panels, fuel cells, an electrolyzer, a converter, and a hydrogen storage tank. A robust techno-enviro-economic (3E) analysis is conducted through comprehensive modeling for the system components using MATLAB/Simulink®. In this validated model, the essential parameters have been calculated: PV plant power, area and efficiency, electrolyzer efficiency, flow rate and power, stack power, area and efficiency, total LCOE of the integrated components, and CO 2 emission reduction. Moreover, the NSGA-II coupled with TOPSIS decision-making approach and Gaussian Process Regression machine learning method with selection kernel function are also utilized as a novel inclusion for the prediction and optimization of the 3E performances of this hybrid system. To obtain a multidimensional view of the optimization, six key decision variables of total stack power, fossil fuel-based generator energy, total CO 2 emissions coming from hydrogen production, total FC system voltage, module area, and number of PV modules have been adopted. The optimization problem encompasses maximizing the total fuel cell stack power and carbon emission reduction, while simultaneously minimizing the total stack area and levelized cost of energy. The simulation outcomes reveal that the stack can reach its maximum output power of 350 kW when operating temperatures are between 40 °C and 55 °C and there are more than 380 cells in the stack. Also, the LCOE was found to be less than $2/kWh for solar radiation above 250 W/m2 and PV outputs reaching 100 W. Further, Increasing FCs from 10 to 400 reduces CO 2 emissions by roughly 13% at 100 °C. Ultimately, the optimal configuration of the system yields stack power of 1589 kW, a total stack area of 269.9 m2, and total CO 2 emission reduction of 1268 ton CO2 , respectively. • Robust 3E analysis using MATLAB-based techno-environmental-economic study. • ML tool using GPR and GA optimization method used for performance optimization. • LCOE is less than $2/kWh for solar radiation above 250 W/m2 and 100 W PV output. • The PVFCEHST model exhibits a high degree of reliability and a robust integrated model. • FC power efficiency reaches 60% when operational temperature is between 40 and 55 °C. [ABSTRACT FROM AUTHOR]

It is well known that solving the greenhouse effect caused by increasing CO 2 emissions is urgent, and CO 2 methanation reaction is a popular research area as one of the effective ways. However, there are great obstacles and challenges to develop catalysts with higher stability and catalytic activity. In order to reduce the activation energy required for methanation reactions, it is expected to introduce another metal into monometallic catalysts to form bimetallic catalysts through the synergistic effect between the bimetallic phases. This paper reviews the advantages of metal-phase combinations for bimetallic catalysts applied to CO 2 methanation. The main synthetic methods used to prepare bimetallic catalysts in recent years are discussed. The effects of bimetallic phase synergy, bimetallic phase structure, metal particle size and dispersion, metal component ratio, and carrier effect on catalyst performance are analyzed. Finally, the challenges and application prospects of bimetallic catalysts for CO 2 methanation are presented. • Hydrogenation mechanisms for combinations of combination of dual active components are analyzed. • The preparation method and auxiliary preparation technology of bimetallic catalyst are discussed. • The synergistic effect between the two metal phases should sometimes be enhanced and sometimes suppressed. • The structure between the two metal phases improves the efficiency of the catalysts. • Different catalyst particle sizes affect product generation in CO2 hydrogenation reactions. [ABSTRACT FROM AUTHOR]

The hydrogen combustion engine (H 2 ICE) is known to be able to burn H 2 , producing no CO 2 emissions and extremely low engine-out NO x eo emissions. In this work, the potential to reduce the NO x eo emissions through the implementation of electric hybridization of an H 2 ICE-equipped passenger car (H 2 -HEV), combined with a dedicated energy management system (EMS) is discussed. Achieving a low H 2 consumption and low NO x eo emissions are conflicting objectives, the trade-off of which depends on the EMS and can be represented as a Pareto front. The dynamic programming algorithm is used to calculate the Pareto-optimal EMS calibrations for various driving missions. Through the utilization of a dedicated energy management calibration, H 2 -HEVs exhibit the potential to decrease the NO x eo emissions by more than 90%, while, decreasing the H 2 consumption by over 16%, compared to a comparable non-hybridized H 2 -vehicle. The present paper represents the initial potential analysis, suggesting that H 2 -HEVs are a viable option towards a CO 2 -free mobility with extremely low NO x eo emissions. • H 2 -HEVs with a dedicated energy management can achieve extremely low NO x eo • Mixed H 2 -HEVs have a superior H 2 -NO x eo trade-off than series and parallel H 2 -HEVs • Mixed H 2 -HEVs lower the NO x eo emissions by 90% and decrease the H 2 consumption by 16% • H 2 -HEV's optimal EMS calibrations for the entire H 2 - NO x eo Pareto front [ABSTRACT FROM AUTHOR]

The sustainability issue in the transportation sector brings the electric vehicle (EV) as a new promising solution for reducing carbon emissions. However, the EV adoption faces issues regarding range, recharging time, and high initial investment. To enhance the adoption, supporting infrastructures should be planned. Therefore, forecasting the growth of EV adoption becomes important to help industries and government in strategic decision making. This paper provides a literature review about forecasting methods in EV ownership, which includes studies from 2011 to March 2023. This will contribute to highlight the current methods and stimulating more developments of forecasting methods related to EV ownership. [ABSTRACT FROM AUTHOR]

[Display omitted] Waste-to-Energy (WtE) technology is the most effective solution for managing non-recyclable wastes through mass burning and energy recovery. Owing to the significant volumes of plastics in China's industrial solid wastes (ISW), a large amount of greenhouse gases (GHG) is generated during the incineration process. Therefore, monitoring GHG emissions from WtE facilities is essential. Owing to the lack of suitable accounting models and characterized fossil carbon fraction (FCF) data, current studies use default values provided by the Intergovernmental Panel on Climate Change's (IPCC), which increases calculation inaccuracies. Therefore, this study established an improved method to accurately account for carbon emissions during solid waste incineration by firstly using radiocarbon dating by accelerator mass spectrometry (AMS) technique to determine the FCF of the solid waste components in China. Monte Carlo analysis was employed to perform the sensitivity analysis, and the results indicated that there was a significant deviation between the measured value and IPCC's default values of FCF, 3.2, 32.48, 93.39, 93.76, 90.49, and 93.8 % for paper, cotton, synthetic textiles, artificial rubber, artificial leather, and plastics, respectively. By replacing coal with ISW in a 2 × 110 t/h circulating fluidized bed boilers, 9.251 × 104 t CO 2 -eq emissions were reduced, and the carbon emission factor reached 0.56 t CO 2 -eq/t waste. This study complements the research gap fossil carbon data of wastes in the IPCC guidelines and provides a more accurate and effective way to calculate carbon emissions during ISW incineration treatment. [ABSTRACT FROM AUTHOR]

• A new capture process of NH3-containing gas treatment with ionic liquids was designed. • MOGA method was employed to optimize the process operational parameters. • The comparison of water scrubbing and IL-based process was carried out. • TPC of enhanced process can be reduced by 32.41 % than water scrubbing. Ammonia (NH 3) emission has caused serious environment issues and aroused worldwide concern. The emerging ionic liquid (IL) provides a greener way to efficiently capture NH 3. This paper provides rigorous process simulation, optimization and assessment for a novel NH 3 deep purification process using IL. The process was designed and investigated by simulation and optimization using ionic liquid [C 4 im][NTF 2 ] as absorbent. Three objective functions, total purification cost (TPC), total process CO 2 emission (TPCOE) and thermal efficiency (η eff) were employed to optimize the absorption process. Process simulation and optimization results indicate that at same purification standard and recovery rate, the novel process can achieve lower cost and CO 2 emission compared to benchmark process. After process optimization, the optimal functions can achieve 0.02726 $/Nm3 (TPC), 311.27 kg CO 2 /hr (TPCOE), and 52.21% (η eff) for enhanced process. Moreover, compared with conventional process, novel process could decrease over $ 3 million of purification cost and 10000 tons of CO 2 emission during the life cycle. The results provide a novel strategy and guidance for deep purification of NH 3 capture. SYNOPSIS: This work guides to optimization of the process for NH 3 capture and NH 3 resource recovery based on ionic liquids. [Display omitted] [ABSTRACT FROM AUTHOR]

Biomass can partially replace fossil fuels for power to reduce CO 2 emissions and save non-renewable resources. In the pulp and paper industry, a waste biomass of calcium lignin was obtained by treating chemo-mechanical pulp (CMP) wastewater with calcium oxide. To investigate waste calcium lignin and its potential use in power generation systems in place of fossil fuels, a basic experiment on calcium lignin gasification was conducted. A model of gasification combined power generation was developed. The results showed that, the gasification temperature was 800 °C, the equivalence ratio (ER) was 0.25, the syngas yield was 78.2 wt%, the lower heating value (LHV) of the syngas was 5.15 MJ/Nm3, and the highest cold gas efficiency (CGE) was 57.84%. In the model, the generated electricity and CO 2 emissions were 1.10 kg/kWh and 0.62 kg CO 2 /kWh, respectively. The use of calcium lignin biomass reduced 35.42% of CO 2 emissions compared to a traditional coal-fired power plant. In addition, the product value-added was 1.17 RMB per kWh, and this was 82.81% higher than that of the 0.64 RMB of traditional coal-fired power plant. [Display omitted] • Production of syngas from the solid waste of calcium lignin by gasification. • Syngas was used for power generation to reduce the use of fossil fuels. • A model was established to investigate the emission reduction effect of CO 2. [ABSTRACT FROM AUTHOR]

Considering the escalating global warming and its severe consequences, the exploitation of hydrogen, an eco-friendly energy carrier, is gaining great interest. This paper comprehensively reviews the most common hydrogen production, storage, transportation and utilization processes, while their effectiveness is explored from energy, water, economic and environmental perspectives. Their main characteristics, advantages, shortcomings and challenges are discussed as well. The research reveals that the hydrogen's water footprint, energy consumption, carbon emissions, and cost vary significantly depending on the specific technologies used throughout its life cycle, from production to end use. For instance, fossil fuel-based hydrogen production methods, such as steam methane reforming, offer elevated energy performance and cost-effectiveness, but have a significant carbon footprint. In contrast, water electrolysis is environmentally friendly, but requires more water and has lower energy efficiency. Besides, high-pressure containers are the preferred method for hydrogen storage, while liquid and solid storages are better suited for high-energy-density applications. Regarding hydrogen transportation, pipelines are effective over long distances, whereas tankers are convenient for short distances. Furthermore, fuel cells are more energy, carbon and water efficient when using hydrogen as fuel, but they are generally more expensive than internal combustion engines. [Display omitted] • Hydrogen production, storage, transportation and utilization methods are reviewed. • Their energy efficiency, water use, cost, and environmental impact are explored. • Key recommendations to boost the utilization of hydrogen systems are outlined. • Fossil fuel-based technologies are more energy-efficient and cost-effective. • Renewable-based processes are more environmentally friendly but water-intensive. [ABSTRACT FROM AUTHOR]

In the light of the recent standards proposed by the European Union in terms of CO 2 emissions for the internal combustion engines, the attention is increasingly focused on e-fuels, among which the renewable-produced hydrogen. The present paper proposes a numerical methodology for 3D-CFD in-cylinder simulations of hydrogen-fuelled internal combustion engines. The proposed framework includes in-house developed models for ignition, knock and heat transfer and it is based on the G-equation combustion model. The predictive capabilities of the methodology are validated against experimental data on a single-cylinder naturally-aspirated diesel engine converted for spark-ignited hydrogen operation. Specifically, H 2 is direct injected thanks to two injectors installed on the cylinder head. Moreover, a spark plug is added and the compression ratio is lowered. The investigated conditions cover different revving speeds (from 1500 rpm to 3000 rpm) and equivalence ratios (0.4, 0.6 and 0.8). The satisfying agreement between numerical results and experimental counterparts paves the way to future studies (e.g. on emission modelling) and engine optimization. • Simplification of geometry of injectors preserved the accuracy of the results. • Mixture homogeneity in swirling flow field is influenced by injected amount of fuel. • Flamelet combustion model G equation is reliable for engine combustion simulation. • Wide range of operating conditions can be simulated with same numerical setup. [ABSTRACT FROM AUTHOR]