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Utilization of the quality-upgraded waste paper in the manufacture of paper and board will reduce the wood consumption and pulping energy. While the optical property of the fibers from recycled old newspaper is very poor, in-situ calcium carbonate formation on those fibers by injecting carbon dioxide to the mixed slurry of those pulp and calcium oxide improved their brightness. Upgrading recycled old newspaper to substitute more expensive wood furnish, such as recycled old magazine, was successfully demonstrated in the present study. This study showed that the in-situ calcium carbonate formation process improved the optical quality of the recycled old newspaper by covering colored impurities with newly formed calcium carbonate, and improved calcium carbonate retention in papermaking process by attaching them to fibers. The strength reduction by the presence of newly formed calcium carbonate in the paper was recovered by adding strength agent. High ash retention at high ash content under the strong turbulence in the modern paper mill was achieved by the application of the in-situ calcium carbonate formation method. The quality-upgrade of recycled fibers and cost saving in the manufacture of duplex paperboard were demonstrated in the mill trial. [ABSTRACT FROM AUTHOR]

Pulp and paper is considered to be the fourth most energy-intensive industry (EII) worldwide. However, as most of the CO 2 emissions are of biomass origin, this sector has the potential to become a carbon-negative industry. This study proposes a new concept for conversion of the pulp and paper industry to carbon negative that relies on the inherent CO 2 capture capability of the Kraft process. The techno-economic performance of the proposed carbon-negative system, based on calcium looping (CaL) retrofitted to a pulp and paper plant, was evaluated. The effect of CaL design specifications and cost assumptions on the thermodynamic and economic performance were evaluated. Under the initial design assumptions, the reference pulp and paper plant was shown to turn from electricity importer to electricity exporter with the cost of CO 2 avoided equal to 39.0 €/tCO 2. The parametric study showed that an increase in the fresh limestone make-up rate resulted in a linear increase of the specific primary energy consumption for CO 2 avoided (SPECCA) and a reduction in the amount of electricity exported to the electric grid. This translates into an increase in the price of pulp and newsprint, and the cost of CO 2 avoided. This study has also demonstrated that the pulp and paper industry has high potential to become carbon negative. It has been shown that carbon capture and storage would become economically viable in this industry if the negative CO 2 emissions are recognised and a negative CO 2 emissions credit of at least 41.8 €/tCO 2 is implemented. • Concept of the Kraft process with inherent CO 2 capture. • Calcium looping for CO 2 capture is integrated in the lime cycle. • Reference pulp and paper plant turns from importer to exporter of electricity. • Pulp and paper industry has a high potential to become carbon negative. • Economic feasibility needs the inclusion of biogenic emissions in emission trading. [ABSTRACT FROM AUTHOR]

To effectively mitigate climate change, policymakers worldwide established various GHG tracking and trading systems. In the light of ambitious climate goals, stricter regulations, and increasing demand for climate action, various groups such as researchers and governmental institutions suggested additional approaches. This paper addresses the complexity that arises from the breadth of suggested approaches and implemented systems for GHG tracking and trading. By doing so, it synthesizes relevant dimensions in a way that is understandable to enterprises and policymakers, enabling them to design meaningful systems incorporating the reduction of GHG emissions and advance cleaner production. Therefore, this paper presents a first-of-its-kind taxonomy of GHG tracking and trading approaches through a systematic literature review. It illustrates ten main design and implementation dimensions with 30 corresponding characteristics. To accelerate decarbonization, this paper sets impulses for future GHG tracking in the electricity sector based on semi-structured expert interviews. Consecutively, it provides policy directions for CO 2 -adaptive decision-making for enterprises, formulated as a Call for Action with seven prospective questions. These include, for example, questions concerning technical aspects like data management, legal issues like the sufficiency of existing data security and privacy regulations, as well as economic topics like the calculation of an appropriate local and temporal granularity. • Presenting a first-of-its-kind taxonomy of GHG tracking and trading approaches through a systematic literature review. • Creating targeted knowledge for enterprises and policymakers for designing meaningful systems to reduce GHG emissions. • Setting impulses for future GHG tracking in the electricity sector based on semi-structured expert interviews. • Providing policy directions for CO 2 -adaptive decision-making for enterprises, formulated as a Call for Action. [ABSTRACT FROM AUTHOR]

In recent years, there has been a notable surge in focus on the mitigation of carbon emissions, mostly motivated by the urgent concern about global warming and its adverse impacts on the Earth's climate. Power-to-gas (PtG) systems have emerged as a promising technological solution in the pursuit of mitigating carbon emissions. This paper presents a mathematical modeling framework that aims to accurately represent the power-to-gas system integrated with wind power plants while taking into account the technological constraints of the system in practical scenarios. To analyze the proposed system under the stresses, worst situations caused by existing uncertain parameters, especially wind power, is modeled using a risk modeling technique called downside risk constraints (DRC). The DRC endeavors to mitigate the likelihood of situations resulting in significant stresses by incorporating an expected downside risk into the proposed framework. This paper will provide a number of conservative tactics to be employed in the decision-making process under the realizations of uncertainties. These tactics, including strategic operational control strategies, provide a structured approach for decision-making under uncertain conditions. By incorporating downside risk constraints, the framework enables conservative decision-making that prioritizes mitigating potential losses and minimizing the operational risk within scheduling horizon of proposed PtG facility. The findings demonstrate that the implementation of PtG technology has the potential to yield a substantial reduction in external energy consumption, namely by 39.1 %. Additionally, it has been seen that PtG may effectively mitigate carbon emissions, resulting in a decrease of 38.9 %. The utilization of PtG technology and gas storage will result in a substantial reduction in wind curtailment, ultimately leading to a near elimination of curtailment. Further study is conducted on the model in order to explore the benefits of carbon and methane storage, as supported by the results obtained. [ABSTRACT FROM AUTHOR]

The conventional air conditioning system used in high-speed railways has limitations in heating performance and environmental impact, necessitating the exploration of alternative refrigerants. The transcritical CO 2 system has gained popularity due to its exceptional heating efficiency and environmental benefits. This study aims to evaluate the energy and environmental potentials for transcritical CO 2 systems in high-speed trains based on four-vertical-and-four-horizontal railway lines within different climatic regions of China. A high-fidelity transcritical CO 2 system model was first developed and validated through experiments. Then, a comprehensive energy and environmental evaluation method was proposed and applied to the four-vertical-and-four-horizontal railway lines. The results indicated that the transcritical CO 2 system had a superior heating performance and competitive cooling performance based on daily and annual operations. Furthermore, the transcritical CO 2 system exhibited significant environmental advantages with lower total life cycle climate performance for all lines, with an average emissions reduction ratio of 17.6% and a maximum emissions reduction ratio of 26.98%. These findings highlight the competitive energy performance and outstanding environmental benefits offered by transcritical CO 2 systems as promising alternatives to air conditioning systems in railway transportation. • This paper evaluates the potential of theCO 2 system in high-speed trains from an energy performance and environmental benefits perspective. • A high-fidelity model of the transcritical CO 2 system is developed and validated for effectiveness through experiments. • The energy and environmental evaluations are conducted based on China's four-vertical-and- four-horizontal railway lines. • The results indicate that the CO 2 system presents a competitive alternative for air conditioning systems in high-speed trains. [ABSTRACT FROM AUTHOR]

Tropical climate-smart agriculture could be a cost-effective and scalable nature-based solution toward achieving net-zero greenhouse gas (GHG) emissions in the coming decades. Nevertheless, the lack of integrated on-farm CO 2 , CH 4 , and N 2 O flux measurements remains a barrier to including these systems in certification programs and the carbon (C) market. This systematic literature review critically examines field-measured GHG emission studies within climate-smart agri-systems in Brazil, aiming to: (i) integrate GHG-measured data, (ii) explore geographical representativeness and connections between organizations and authors, (iii) analyze distributions of studied GHG molecules, climate-smart system types, and productive components, (iv) conduct a meta-analysis on the adoption of climate-smart agriculture, and (v) identify methodological and scope gaps, providing insights for future research directions. The systems considered include no-till, well-managed pasture, integrated crop-livestock, and integration with trees (i.e., crop-forestry, livestock-forestry, crop-livestock-forestry, and multistrata agroforestry). Out of 1200 papers mentioning GHGs and climate-smart systems, 74 contained reliable on-farm flux measurements. Most authors were Brazilians affiliated with Embrapa and public Universities. Studies concentrated on the Atlantic Forest and Cerrado, with scarce data for other biomes. Over half of the trials assessed individual GHG molecules and only one climate-smart system. Urochloa spp. and Avena spp. were the most studied forage genera, while soybeans and corn dominated annual crops. Eucalyptus spp. and beef cattle were common trees and animals. No-till, integrated crop-livestock, and agricultural integrations involving trees showed soil C–CH 4 influx from 0.8 to 1.0 kg ha−1 y−1. Transitioning from pasture monoculture to integrated systems decreased N–N 2 O emissions by up to 1.63 kg ha−1 y−1. Converting extensive grazed land to intensified-integrated systems reduced animal CH 4 intensity, with cuts of up to 122 g CH 4 per kg of average daily weight gain. Future research must urgently address methodological issues, such as de-standardization (e.g., 8–10 flux units found per GHG molecule) and the absence of crucial ancillary variables. In conclusion, adopting diversified climate-smart agri-systems shows potential to mitigate GHG emissions, but caution is advised when extrapolating our numerical findings due to limited data across Brazilian edaphoclimatic conditions. We urge scientists to prioritize frequent on-farm measurements of all three GHGs (CO 2 , N 2 O, and CH 4) along with agroecosystem C sequestration across multiple climate-smart systems, enabling reliable and comparable net GHG flux calculations to identify the most sustainable option. Advancing and standardizing GHG measurements in Brazil offer an opportunity to enhance GHGs inventory accuracy, calibrate models, and promote policies and investments that expand refined tropical climate-smart agriculture. [Display omitted] • We systematically reviewed GHG measurements in Brazilian climate-smart agri-systems. • Well-managed pastures, no-till, and integration-based systems mitigate GHG emissions. • Brazilian GHG dataset incompletely represents systems and environmental complexities. • Producing agri-GHG field data is still vital for policies, investments, and C market. • Future GHG research should standardize flux units and include ancillary variables. [ABSTRACT FROM AUTHOR]

Given the increasingly severe challenges of global climate change and sustainable development, accurate prediction of daily carbon dioxide (CO 2) emissions has become crucial. However, current research on real-time daily forecasts remains relatively scarce, often limited to annual predictions and point estimates. This paper proposes an innovative integrated model, based on quantile regression and Attention-Bidirectional Long Short-Term Memory (BILSTM), specifically designed for probabilistic prediction of daily carbon emissions. Testing the model on daily carbon emission data from major carbon-emitting countries including China, the United States, India, Russia, and Italy has demonstrated its superior performance across various metrics, including mean squared error (MSE), mean absolute error (MAE), coefficient of determination (R2), and normalized average width of prediction intervals (PINAW), compared to other benchmark models. This achievement not only highlights the model's effectiveness in predicting daily carbon emissions but also provides policymakers with a powerful tool for real-time monitoring and assessment of carbon emissions. Furthermore , the application of probabilistic forecasting methods enables decision-makers to gain a more comprehensive understanding of the potential range of future carbon emissions, providing strong support for the formulation of targeted policies. [ABSTRACT FROM AUTHOR]

Freshwater bodies are found as significant sources of greenhouse gas to the atmosphere, but their quantitative significance is not yet clear. The rapid increase in hydropower dams and associated emissions has received much attention from hydropower industries, environmentalists, and policymakers from across the globe. The tropical/subtropical eco-regions are, particularly, considered as hotspots from greenhouse gas production point of view as the emitted gases are playing a critical role in climate change. The present paper reviews the uncertainty and limitations of greenhouse gas measurement from Chinese freshwater bodies based on available data. Literature reported that carbon dioxide emission from Chinese lakes falls in the range of 0.01–2.16 μmol m−2s−1 except for Poyang Lake. The CO 2 emission from Chinese hydropower reservoirs is estimated as 0.15–1.11, while for rivers, it is 0.44–4.12 μmol m−2s−1. The methane and nitrous oxide emissions are, however, found less than carbon dioxide emission. The CO 2 emission falls in the range of −0.17–0.54 and 1.08–1.70, respectively higher than global lakes and rivers, while the global reservoirs have emission in the range of −0.17–2.98 μmol m−2s−1. The paper also reports the challenges in the estimation and prediction of greenhouse gas emissions from hydropower reservoirs along with suggested mitigation measures. Image 10945 • GHG emissions have been limited by data availability and inconsistencies in methodological approach. • Investigate uncertainty and limitation of GHG measurement. • Literature reveals CO 2 emission from Chinese rivers is twice than lakes and four times than hydropower reservoirs. • CH 4 and N 2 O emissions are however found less than CO 2 emission. • Suggested mitigation measures to minimize the impact of GHG on climate change. [ABSTRACT FROM AUTHOR]

In carbonation reaction, the impact of surfactants on the movement and mass transfer behavior of carbon dioxide bubbles were crucial for the production of high-quality silicon dioxide products. The study employed the Matlab image processing system to investigate the shapes, motion velocities, and rise path of single carbon dioxide bubbles within varying concentrations of cetyltrimethyl ammonium bromide (CTAB) solutions. This exploration aimed to elucidate the effect of CTAB on the movement and mass transfer coefficient (MTRC) of single carbon dioxide bubbles. Alterations in the CTAB solution concentration and bubble sizes significantly influenced the mass transfer and movement characteristics of single carbon dioxide bubbles. The conclusion was drawn through the computation of the MTRC of single carbon dioxide bubbles in deionized water and CTAB solutions: the addition of CTAB significantly reduced the mass transfer efficiency of carbon dioxide in deionized water, with the MTRC of CTAB solutions decreasing as the solution concentration increased. Utilizing the stagnant cap model, it can be concluded that CTAB's reduction of the MTRC of carbon dioxide was attributed to the high viscosity of the medium, low bubble velocity, stable flow conditions, and intensified adsorption degree of CTAB molecules at the gas-liquid interface. According to the significant periodic trajectories of single carbon dioxide bubbles in the stable range, the correlation between the trajectories of compressible bubbles in surfactant solution and mass transfer in liquid phase was established, and the previous method based on rigid sphere model was modified. The paper proposed the mechanism of CTAB's influence on single carbon dioxide bubbles, offering crucial theoretical insights into the industrial application of surfactants in the carbonation process for producing silicon dioxide. [ABSTRACT FROM AUTHOR]

Much of the existing literature on greenhouse gas peaking focuses on carbon dioxide (CO 2) emissions, however there is a lack of research on peaking methane (CH 4) emissions, the second-largest greenhouse gas. This paper attempts to determine and classify the peaking status of anthropogenic CH 4 emissions in 188 economies over the period 1970–2021 using a trend analysis model and a decoupling model. Fifty-eight economies achieved a peak in total CH 4 emissions, and 125 economies achieved a peak in CH 4 emissions per capita, showing marked spatial-temporal variation. Emissions generated by the agricultural sector peaked in 84 economies, followed by the energy sector in 63 economies, and the waste sector in 34 economies. Of these, the most volatile was the peak in emissions in the energy sector. There were 45 benign peaking economies and 13 pseudo-peaking economies. The majority of developed economies showed strong decoupling after reaching their peaks. The agricultural sector had the most peak economies which achieved strong decoupling. Among the factors influencing national pathways to peak CH 4 emissions, technological progress driving CH 4 emissions reductions in benign peak economies is the most important. This study provides targeted strategies for global and national CH 4 emissions reduction, particularly given the historical trend and current profile of economies at different levels of emissions evolution. • Peaking status of CH 4 emissions in 188 economies during 1970–2021 is evaluated. • 58 economies peaked in total CH 4 emissions and 125 in per capita emissions. • Agriculture-, energy- and waste-related emissions show various peaking patterns. • There are 45 benign peaking economies and 13 pseudo-peaking economies. • Factors influencing national pathways to peak CH 4 emissions are identified. [ABSTRACT FROM AUTHOR]

The application of transcritical CO 2 cycle in the thermal management system of electric vehicles has become increasingly prevalent, but the existing thermal management system architecture has not been optimized to specifically enhance the performance of CO 2 refrigerant. This paper analyzes the impact of various heat exchanger arrangements on CO 2 thermal management system and evaluates system configurations based on a new performance index, cycle coefficient of performance. The effects of air temperature, ambient temperature, and heat load on system performance are conducted with a high precision model. The chiller is connected in parallel-series with indoor heat exchangers, resulting in a maximum coefficient of performance improvement of 27.89% at an indoor air inlet temperature of 10 °C, and a maximum coefficient of performance improvement of 21.69% at an ambient temperature of 5 °C, under simultaneous heating conditions. The radiator is placed on the windward of gas cooler, leading to a maximum coefficient of performance increase of 4.85% in heating mode, but a maximum coefficient of performance decrease of 9.84% in cooling mode. The evaluation of these configurations across different operating cycles reveals that the parallel-series connection is well-suited for the new European driving cycle, showing an 18.4% improvement in cycle coefficient of performance compared to the series-parallel connection. The windward arrangement of radiator proves effective for highway fuel economy test cycle in winter and the new European driving cycle in summer. This study provides effective instruction for configuration design and evaluation of transcritical CO 2 vehicle thermal management systems. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO 2) and hydrogen (H 2) present substantial feedstock potential for advancing sustainability in the chemical industry. In this paper, a new integrated system is proposed consisting of four subsystems, including an ICT-OEC six-step Cu–Cl cycle, a CO 2 capture using monoethanolamine (MEA), an ammonia production unit, and a methanation unit. The simulation of these subsystems was carried out using Aspen Plus software. Based on literature indicating a 3-step Cu–Cl cycle producing 125 TPD of hydrogen, comparative simulations of a similar-capacity six-step Cu–Cl cycle were conducted for the current analysis. All related values correspond to it. Converting CO 2 into methane and nitrogen into ammonia holds great promise in reaching the net-zero target and fostering sustainability. A comprehensive cradle-to-gate Life Cycle Assessment (LCA) investigates the environmental impacts of ammonia and methane production using green hydrogen and CO 2. Significantly, the utilization of renewable energy sources such as nuclear, wind, and hydropower in the CO 2 refinery process generates a net negative Global Warming Potential (GWP). It was noted that the GWP value of the electrical grid could increase significantly, reaching up to 370,000 kg CO 2 eq., particularly when producing 23,277.2 kg/h of ammonia and 2141.71 kg/h of methane at a hydrogen consumption rate of 5211 kg/h (125 metric tons of H 2 per day). The significant environmental impact of the CO 2 refinery process is notably influenced by the choice of electrical grid mix as the energy source. However, in the case of photovoltaics as an energy source, the value of 0.517 kg sb eq, surpasses that of the electrical grid mix. However, nuclear energy emerges as a particularly low-GWP impact, with values of −4190 and −4140 CO 2 kg eq. for the 3-step and 6-step Cu–Cl cycles, respectively. The findings suggest that the CO 2 refinery process generates a carbon credit in both scenarios. Based on the findings of this study, policymakers have a basis for developing effective strategies to address and alleviate environmental impacts. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, a multi-step framework to design flexible power-to-methane processes is presented. The approach considers all crucial parts of the power-to-methane process, including the renewable energy source. The aim is to provide a design that allows for feasible operation under the fluctuating conditions induced by the renewable energy source at all times. For each part of the process, the operating windows are analyzed and optimized under different site-specific constraints, and recommendations for actions regarding the technical implementations are provided. The impact of the carbon dioxide source is scrutinized, and subsequent scheduling optimization is performed to determine necessary storage capacities. The framework is demonstrated on two carbon dioxide availability scenarios where the renewable energy source is a wind turbine coupled to a polymer exchange membrane electrolyzer that produces hydrogen, which is then converted to methane in a fixed-bed reactor. The results show that the feasible operation of the system strongly depends on the site-specific conditions. In particular, the availability of carbon dioxide impacts the flexibility of the methanation reactor. When the stochiometric ratio between hydrogen and carbon dioxide cannot be sustained, the operating window of the reactor deteriorates significantly. However, it is shown that appropriate integration and scheduling of storage capacities debottlenecks the reactor and enables the utilization of all electricity generated by the wind turbine. • A framework for the design of flexible power-to-methane systems is introduced. • Optimization approaches for each step of the framework are provided. • A dynamic optimization approach for storage integration is given. • The impact of the carbon dioxide provision flexibility is investigated. • The framework is tested in a case study with an onshore wind turbine in Germany. [ABSTRACT FROM AUTHOR]

The gas-confined supercritical CO 2 (scCO 2) foaming technology is a clean method to prepare porous polymer surfaces but has never been applied to the construction of SLIPS due to the limitation of uneven and hard-controllable cell structure. In this paper, the surface of polystyrene (PS) is covered by a PS surface instead of the frequently-used rigid polymer films as a barrier, subsequently, both PS surfaces are foamed to prepare porous PS surfaces with uniform cell morphology and widely-adjustable cell size, which have active influences on the shear-resistant ability of SLIPS. Meanwhile, there is no solid waste generated in this process, and the production efficiency is at least doubled. The SLIPS with a cell-cell space of 0.07 μm and a mean cell diameter of 0.25 μm presents the optimal shear-resistant ability (CAH = 4.4° ± 0.8° after being sheared at 8500 rpm for 10 min). Consequently, this work proposes a clean, efficient, and facile path for preparing SLIPS with water-repellency, shear resistance, self-clean, and self-healing properties. [ABSTRACT FROM AUTHOR]

Mitigating greenhouse gas emissions is a significant global challenge, and precise prediction of carbon emissions holds the utmost importance for China to attain its dual carbon goal. To overcome the limitations of existing studies using a single forecasting method, based on quadratic exponential smoothing, multiple linear regression, and Gaussian process regression models, this paper constructs a carbon emission combination forecasting model with the generalized induced ordered weighted average (GIOWA) operator and analyzes carbon emission reduction performance. Empirical testing utilizing China's carbon emission data from 1980 to 2020 reveals the following findings: (1) The GIOWA combination forecasting model significantly enhances the accuracy of carbon emission forecasts, with an average accuracy exceeding 99.5% over the sample period, surpassing various single forecasting methods. (2) The carbon emission reduction target can be achieved under three different scenarios of low, average, and high GDP growth rates. Specifically, under the low growth rate scenario, China can achieve a 60% reduction in carbon intensity by 2025 and a 65% reduction by 2030. This study offers valuable decision support for the development of effective carbon reduction policies. [ABSTRACT FROM AUTHOR]

Alkaline cement binders offer innovative and ingenious solutions to combat global energy demand, waste generation, and greenhouse emissions. In their production, alkaline binders consume waste materials with less energy and emit less carbon dioxide compared to ordinary Portland cement. In this review paper, a prime materials-based classification method was used to summarize the recently reported alkaline binders which comprised with the types of coal ash-based, clay-based, slag-based, and mine waste-based. These alkaline binders were further sub-divided into co-binder types, depending on the additional binder incorporated to modify and enhance the cementitious properties. This paper summarises the key properties of recent alkaline binders in terms of their rheological, mechanical and microstructural aspects, highlighting the composition of the binding and alkaline materials with curing conditions in the processing of cement paste, mortar or concrete. The publications reviewed emphasize the potential of alkaline cement to consume various waste precursors such as ashes, clays, industrial slags, and mine tailings along with different waste additives to improve the fresh and hardened characteristics of alkaline cement by reducing the adverse cost and environmental impacts. The classified alkaline binders reveal some vital results which can be used for optimum mix design combinations for actual field applications. The physicochemical properties of the precursors and alkaline materials and the curing regimes mainly affect the fresh and hardened properties of various alkaline binder compositions. Finally, the potential for substituting waste alkaline sources instead of commercial alkaline solutions is highlighted to make the alkaline binders completely waste-based. [ABSTRACT FROM AUTHOR]

In this paper, the idea of Underground coal gasification coupled with supercritical carbon dioxide storage is proposed based on the problems of Underground coal gasification combustion area and carbon dioxide storage site, which provides a new technical approach for carbon peaking and carbon neutrality in the coal sector. At the same time, to solve the underground coal pillar design problem in the popularization and application of UCG-CCS, this paper adopts numerical simulation and theoretical analysis methods to reveal the deformation mechanism and bearing characteristics of "hyperbolic" type coal pillar in UCG-CCS. The results of this study are as follows: ① The injection of supercritical CO 2 into the underground goaf can effectively reduce the load of the coal pillar bearing the overlying strata and improve the bearing capacity of the "hyperbolic" protective coal pillar. ② The size of the "hyperbolic" coal pillar in UCG-CCS slightly influences the coal pillar's stability under certain injection pressure. For safety in practical engineering, it is necessary to ensure that the CO 2 injection pressure reaches its critical pressure of 7.38 MPa. ③ Based on numerical simulation results, when the width of the combustion cavity is 40 m, the width of the protective coal pillar is 56 m, the injection pressure of supercritical CO 2 is 7.38 MPa, and the sealing depth ranges from 800 m to 1200 m, the protective coal pillars are in a stable state due to the pressure effect of supercritical CO 2 on the coal pillar and the roof. The research results of this paper have important practical significance for promoting the site selection, product design, and application of UCG-CCS and provide a technical means for the coal industry to achieve carbon peak and carbon neutrality. [ABSTRACT FROM AUTHOR]

In this paper, a cleaner pyrolysis strategy combining microwave heating, catalyst and carbon dioxide was explored for converting biomass components into higher quality products. Catalytic pyrolysis was more favorable for the decomposition and conversion of complex biomass structures. For furfural residue pyrolysis, potassium sulfate contained in sample served as the main catalytic component. Potassium sulfate promoted the increase of phenols in bio-oil. Notably, carbon dioxide atmosphere promoted the decomposition of substances and exerted a significant effect on biomass pyrolysis, which increased bio-oil yield and declined gas yield. When the pyrolysis atmosphere was changed from nitrogen to carbon dioxide, the I D /I G ratio decreased from 1.07 to 0.74, indicating that carbon dioxide decreased defect structure in biochar. Carbon dioxide enriched the porous structure and surface roughness of biochar. Also, carbon dioxide as a carrier gas was found to be more effective than nitrogen in improving the heating values of biochar and the acidity of bio-oil under carbon dioxide was lower than that under nitrogen, which was conducive to the subsequent utilization of biochar and bio-oil. Carbon dioxide promoted the production of alcohols, alkenes, and alkanes in bio-oil. Beneficially, the interaction of cellulose and lignin inhibited the release of hydrogen chloride. At last, this study also provides insights into the mechanism of catalyst and CO 2 on biomass microwave pyrolysis. [Display omitted] • A cleaner pyrolysis strategy combined microwave heating, catalyst and CO 2. • CO 2 increased bio-oil yield while declined gas yield significantly. • CO 2 improved the porous structure and heating value of biochar. • K 2 SO 4 promoted the increase of phenols in bio-oil. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of artificially synthesized C–S–H accelerators (CAs) on concrete properties and analyzes their potential advantages for the precast concrete industry. The study found that adding CAs improves the workability of concrete while also significantly boosting its early compressive strength (particularly within 24 h). This characteristic showcases the dual-effect nature of CAs as additives. Notably, adding 1.5 wt% (relative to the weight of cement) CAs may boost the 6-h strength of concrete to 16.6 N/mm2, meeting the conditions for demolding. This could allow precast concrete plant molds to complete four turnovers within 24 h, thus improving production capacity. Importantly, using CAs may eliminate the need for heat curing during production, thereby reducing the carbon footprint and energy use in the manufacture of precast concrete. [Display omitted] • The C–S–H accelerators improve the early strength of precast concrete. • C–S–H accelerators play a role in improving the workability of concrete. • The utilization of C–S–H accelerators demonstrates dual effects. • The C–S–H accelerator can replace the thermal curing program. • C–S–H accelerators help reduce energy consumption and carbon dioxide emissions. [ABSTRACT FROM AUTHOR]

This paper provides a multi-actor perspective on the realization of new infrastructures, motivated by the necessity for infrastructures to support the ongoing climate and energy transition in general, and CO2 transport infrastructures for carbon capture, utilization and storage (CCUS) in particular. We develop a general model to represent infrastructures that allows for a unique decomposition into 'elementary infrastructure components' based on heterogeneous user requirements. Notably, it incorporates a cost function with a very generic and adaptable structure, for which we can still explicitly determine the costs of each individual component. As a direct consequence an intuitive cost allocation rule is obtained: equal component cost sharing. This allocation rule is in line with existing game-theoretic concepts and satisfies the desirable properties of advantageous scaling and coalitional rationality. Advantageous scaling guarantees that the costs allocated to each existing user do not increase if the number of users grows larger and coalitional rationality ensures that there is no subgroup of infrastructure users that would have a financial reason to object to the cost allocation. Additionally, we examine the application of our model to a prospective CO2 transport infrastructure for CCUS in the port of Rotterdam and the adjoining industry area. • Infrastructures and corresponding costs are modeled in a component-based manner. • Elementary infrastructure components account for heterogeneous user requirements. • Equal component cost sharing satisfies desirable properties and enables cooperation. • Case study demonstrates CO2 transport infrastructures are a suitable application. [ABSTRACT FROM AUTHOR]

Motor systems are ubiquitous throughout the industrial sector, particularly in fluids applications. It is well known that the efficiency of these operations can be greatly enhanced using variable frequency drive (VFD) controls, but adoption of the technology is far from universal. The goal of this paper is to introduce engineering, economic, and environmental analyses to demonstrate benefits to both individual facilities and the state at large. Individual case studies are presented to describe the variety of opportunities for VFD-enhanced motor control; however, this project seeks to describe the combined impact of VFD implementation at a new scale. Data sourced from a U.S. Department of Energy program is used to perform economic and environmental input output analysis to calculate broad impacts of individual audits and recommendations. Results indicate that widespread implementation of VFD controls on motor systems in the industrial sector will introduce significant economic and environmental benefits. One of the scenarios showed a potential reduction of over 4.7 million tonnes of carbon dioxide from regional manufacturing sector as well as a cascading contribution to the regional economy totaling nearly $1 billion. The results are presented as a demonstration of the magnitude of impact that improving control of industrial motor systems can have, as a guide to industry leaders and policymakers about the value of such investments. [Display omitted] • Variable frequency drive (VFD) modifications to industrial motors are described analytically. • Individual micro-scale carbon and cost savings are combined for input-output analysis. • Leveraging VFD control as a universal practice would result in nearly 5 million avoided tonnes of CO 2. • Similarly, economic benefits across the state of Ohio would total more than $1 billion. [ABSTRACT FROM AUTHOR]

To realize the sustainable development of concrete, it is vital to mitigate its consumption and environmental footprint (especially CO 2 footprint) from prolonging the service life through upgrading mechanical and durable performances of concrete. Incorporating nanofillers can effectively tailor the microstructures and performances of bulk cement paste and cement paste at interfacial transition zone in concrete. The hydrated calcium silicate (C–S–H) gels account for half of the volume of hardened Portland cement pastes, and they are the fundamental source of overall properties of concrete. However, the underlying mechanisms of nanofillers on C–S–H gels remains unclear. Herein, this paper underpinned the role of 5 types of representative nanofillers in tailoring the nanostructure of C–S–H gels in cement composites. The research results demonstrated that through the nano-core effect, nanofillers induce the formation of two new C–S–H gels in outer hydration products, namely nano-core-shell element doped low-density C–S–H (NEDLD C–S–H) and nano-core-shell element doped high-density C–S–H (NEDHD C–S–H). The indentation modulus/hardness of NEDLD and NEDHD C–S–H reaches 25.4/0.80 GPa and 46.7/2.72 GPa, respectively. Such superior performances of NEDLD and NEDHD C–S–H derive from the existence of nano-core-shell elements in C–S–H gels rather than the increase in C–S–H packing density. In a short-range, nanofillers form nano-core-shell elements by adsorbing silica tetrahedrons during the hydration process, improving the mechanical properties of C–S–H basic building blocks. In the long-range, the nano-core-shell elements modify the nano-scale performances of C–S–H gels in outer hydration products due to the increase of C–S–H gels' integrality. [Display omitted] [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO 2) is the primary greenhouse gas, with annual emissions reaching up to 54 billion tons globally, leading to an unprecedented acceleration of global warming. In conjunction with carbon capture, utilization, and storage (CCUS), which represents the most advanced and efficient technology for energy conservation and emission reduction, as well as the innovative concept of CO 2 storage in salt caverns, this paper investigates the industrial application potential of supercritical CO 2. Herein the feasibility of large-scale storage of supercritical CO 2 in salt caverns was investigated, focusing on the stability aspect associated with such storage. Specifically concentrating on the impact of upper and lower injection/production pressures and frequencies on the stability of carbon storage in salt caverns, this study utilizes numerical simulation methods to simulate the creep process that occurs in China's bedded salt formations. Numerical simulation results showed that: 1) From the perspective of salt cavern stability, the volume shrinkage, creep and damage degree of surrounding rock during operation all fall within an acceptable range. Consequently, it is feasible to implement carbon storage in these salt caverns for a during of 100 years. 2) Shortening the range of internal pressure will enhance the stability of salt cavern for carbon storage. Furthermore, different pressure intervals have an impact on the creep concentration position within the cavern, primarily resulting in a transformation between internal contraction of surrounding rock and sediment accumulation caused by floor creep by altering the lower pressure limit. 3) The injection and production frequency of salt cavern carbon storage (SCCS) is characterized by a low occurrence rate (<10 cycles). The stability of the cavern can be enhanced by increasing the injection and production frequency, nevertheless, it is important to note that internal pressure remains the primary factor influencing cavern stability compared to the injection and production frequency. • A digital model for supercritical CO2 storage in salt caverns is developed. • The operational parameters for SCCS are designed from the perspective of pressure intervals, injection and production frequencies. • The numerical simulation method is employed to simulate the dynamic change process of SCCS during 100 years of long-term operation, followed by a corresponding stability evaluation. • The alterations in cavity morphology and damage severity of salt caverns utilized for carbon storage are examined. [ABSTRACT FROM AUTHOR]

The rational disposal of Li 2 CO 3 mother liquor is especially critical with the rapid increase in lithium consumption. Most of the current processes are based on solvent extraction, which has still not been applied to practical industry due to their drawbacks. In this paper, a novel process for selective extraction of lithium from high-sodium concentration Li 2 CO 3 mother liquor by NaF precipitation was proposed. 91.3% of lithium precipitated as LiF under the optimal conditions, such as NaF dosage of 1.1 times theoretical amount, temperature of 30 °C, and time of 2 h. Subsequently, the precipitation products were converted by Ca(OH) 2. The conversion of LiF reached 89.9% and the liquid product obtained was LiOH solution with 7.5 g/L Li. The separation factor of Li/Na in the whole process reached 377. This novel process is an efficient, clean, and short process that provides a new idea for the selective synthesis LiOH from high-sodium concentration Li 2 CO 3 mother liquor. • The selective recovery of lithium from Li 2 CO 3 mother liquor was achieved. • 91.3% of the lithium precipitated as LiF under the optimal conditions. • The conversion of LiF reached 89.9% and LiOH solution with 7.5 g/L Li was obtained. • The separation factor of Li/Na in the whole process reached 377. • It is an efficient, clean, and short process. [ABSTRACT FROM AUTHOR]

This paper analyzes the potential contributions of photovoltaic energy to sustainable development in its three dimensions, environmental, economic, and social. For that purpose, the capacity deployments proposed by the main international institutions in the field are considered, mainly the International Energy Agency. The paper focuses on the monetary valuation of avoided CO 2 emissions, and the assessment of the required financial funds. The risk implied by the uncertain photovoltaic prices are dealt with, and methods to manage it are suggested. It is shown that valuing emission at a conservative price and properly discounted, would be enough to finance, on average, the required investments: thus, a low carbon tax is all that would be required to finance the investments. [ABSTRACT FROM AUTHOR]

The aim of this paper is to analyze the main determinants of the economic acceptability of four Green Technologies (GTs): alternative fuel vehicles, energy savings in residential buildings, smart meters and renewable electricity, using a meta-analysis on a sample of 35 selected papers, which provided 245 primary data. This approach allows detecting relationships across heterogeneous studies, avoiding the subjectivity of qualitative surveys. We implement a new two-step procedure. First, we compute a measure of the implicit price for a kilogram of CO2 avoided (PCO2), homogenizing the usable information for the GTs considered. Second, we conduct a meta-regression using the computed PCO2 values to estimate the socio-economic determinants' impact. In general, our results show a wide degree of acceptability for GTs which is stronger among European citizens. In particular, it emerges that, on average, the estimated PCO2 is positive for the GTs considered, and additional positive effects exist when respondents are confronted with an explicit reference to quantitative targets in terms of CO2 abatement, a clear proposal for payment timing, and a specific renewable electricity mix. These results indicate that information and transparency are crucial to spur GTs deployment. Therefore, to support GTs’ market penetration, public and private institutional stakeholders, have to provide “ad hoc” information to the end users, setting a clear and suitable system of prices to increase the economic value end users place on GTs. [ABSTRACT FROM AUTHOR]

The industrial area layout can influence the economic benefit, safety and surrounding environment of an industrial area to a large extent, especially the length of piping and safety. Every year, the construction of new industrial areas requires thousands of tons of steel pipes, resulting in a high consumption of natural resource of iron and high emission of carbon dioxide. Additionally, the long pipeline will increase the energy consumption for material transportation. Meanwhile, accidents in industrial areas can usually result in serious damage to the local environment. So the optimization of industrial area layout holds great significance for natural resource, energy saving, and environment protection. But up to now, very few papers have been reported to consider the use of pipes and safety simultaneously to optimize the layout in industrial area level. Most works only focus on safety aspects, and the impact of connection is ignored. Accordingly, this paper proposes a methodology to optimize the relative position of each plant, whose objective function consists of piping cost and safety cost. In this paper, despite conventional consideration of material piping, steam piping, which features multiple-branches connected pipeline network, is also considered. For safety issues, it is firstly analyzed by qualitative principles to limit position for some specified plants. Then quantitative analysis, including explosion and toxic release, are optimized simultaneously with connection cost. A genetic algorithm is used to solve the proposed model. Kruskal algorithm and Arrangement & Combination are used to calculate the length of steam piping. Finally, a case study illustrates the effectiveness and applicability of the proposed methodology. [ABSTRACT FROM AUTHOR]

Water injection into hydrocarbon reservoirs has been studied in great detail both from the subsurface and from surface perspectives, usually aiming at maximizing the production of low-cost oil. Here, the exergy concept is used to examine the potential life-cycle impact of injecting water into hydrocarbon reservoirs by considering the energy requirements of the process. It is found that the exergy recovery factor, being the ratio between the produced exergy corrected for material and process exergy requirements for its extraction and the gross exergy of the source decreases with time. Usually the process exergy requirements to produce the exergy increases with time. In the case of water injection the main contributors to the process exergy are due to treatment of water and the pumping of reservoir fluids. The method presented in this paper can also quantify the amount of CO 2 per unit volume of the produced oil. It is contended that the volume of water required to produce the oil is an important indicator of the efficiency of water drive recovery of oil. Moreover, the amount of carbon dioxide produced for the extraction of one barrel of oil depends strongly on the water cut f w. in the producers. Below f w = 80% little CO 2 is produced; however, when f w > 90% a small increase in the water cut leads to a large increase of carbon dioxide production. This emphasizes the importance of water management in water drive recovery of oil. • The exergy concept combined with fluid production history can assess the life-cycle efficiency of water injection projects. • The developed methodology can quantify the amount of CO 2 per unit volume of produced oil. • For watercut f w > 90% a small increase of the water cut leads to a large increase of the carbon dioxide production. • Water Utilization Factor (WUF) can be used a measure for cleaner production of hydrocarbon fields. [ABSTRACT FROM AUTHOR]

Enhanced silicate rock weathering for long-term carbon dioxide sequestration has considerable potential, but depends on the availability of suitable rocks coupled with proximity to suitable locations for field application. In this paper, we investigate the established mining industry that extracts basaltic rocks for construction from the Paraná Basin, Sao Paulo State, Brazil. Through a Life Cycle Assessment, we determine the balance of carbon dioxide emissions involved in the use of this material, the relative contribution of soil carbonation and enhanced weathering, and the potential carbon dioxide removal of Sao Paulo agricultural land through enhanced weathering of basalt rock. Our results show that enhanced weathering and carbonation respectively emit around 75 and 135 kg carbon dioxide equivalent per tonne of carbon dioxide equivalent removed (considering a quarry to field distance of 65 km). We underline transportation as the principal process negatively affecting the practice and uncover a limiting road travel distance from the quarry to the field of 540 ± 65 km for carbonation and 990 ± 116 km for enhanced weathering, above which the emissions offset the potential capture. Regarding Sao Paulo State, the application of crushed basalt at 1 t/ha to all of the State's 12 million hectares of agricultural land could capture around 1.3 to 2.4 Mt carbon dioxide equivalent through carbonation and enhanced weathering, respectively. This study suggests a lower sequestration estimate than previous studies and emphasizes the need to consider all process stages through a Life Cycle Assessment methodology, to provide more reliable estimates of the sequestration potential of greenhouse gas removal technologies. • First assessment of the burdens associated with enhanced weathering and carbonation. • Transportation of the material greatly impacts the sequestration potential. • The quarry to field offsetting distance is 550 ± 65 km for carbonation. • On Sao Paulo average, the practice emit 0.110 kg CO 2 eq per kg of CO 2 removed. • The setup burdens of the practice reduce previous sequestration estimates. [ABSTRACT FROM AUTHOR]

The household sector of China is responsible for 11.7% of national energy consumption and 12.6% of carbon dioxide (CO 2) emissions in 2015. Thus, revealing the determinants of household CO 2 emissions (HCE) is extremely important for national efforts towards emissions mitigation. In this context, this paper investigates the driving forces behind national and regional HCE changes employing a temporal Logarithmic Mean Divisia Index (LMDI) model. It also analyses interregional discrepancies in HCE using a spatial LMDI model. This study decomposes the changes or discrepancies of national and regional HCE from 2000 to 2015 into seven key factors. The temporal analysis indicates that household income is the predominant determinant explaining the increase of HCE, whereas energy intensity is the crucial determinant contributing to the mitigation of HCE. The spatial analysis reveals that the number of households and energy intensity are primary driving forces accountable for growing discrepancies in HCE, followed by household income, energy structure and carbon emission coefficient. The analysis also suggests that resourceful and economically developed regions generally have larger potential for mitigation of HCE. The study concludes with some policy recommendations based on the results. [ABSTRACT FROM AUTHOR]

Poorly managed plastic waste ends largely in the environment. For example, visible plastic waste causes pollution in the ocean, and Thailand is ranked sixth in the world for plastic waste generation in the ocean. This study was conducted to monitor and assess plastic waste management following the launch of the 'Thailand Roadmap on Plastic Waste Management (2018–2030)'. The CIPPI model and an impact assessment were used for this purpose. Seventy-three individuals from Thailand's central and local governments were selected to study the plastic bag roadmap. Further, 2378 Thai people and foreign tourists were surveyed about their plastic bag-using behaviours, and thirteen stakeholders were selected for interviews. This study found that the input and output factors were moderate, equalling (x ‾ = 2. 67 , SD = 1.24) and (x ‾ = 3. 07 , SD = 1.20), respectively. Similarly, the process factors were low (x ‾ = 2. 17 , SD 1.29). With respect to outcomes and effects, plastic bag use exhibited a decreasing trend, from 39,983 to 49,816 million bags (−67.03%–83.52%) with a total economic value of 5340–10,408 million baht/year. Carbon dioxide (CO 2) emissions also decreased, at 63,173–78,809-million-kilogram CO 2 eq/year. In conclusion, plastic waste management requires cooperation on the part of all sectors. However, it is important for the government to take responsibility for monitoring, assessing, and improving plans to promote consumption and production sustainability following Goal 12: Responsible Consumption and Production. [Display omitted] [ABSTRACT FROM AUTHOR]

At an annual production of ∼15 million tons, polycarboxylate (PCE) based superplasticizers (cement dispersants) present the most widely used concrete admixture. In this paper, their carbon footprint was quantified considering the three most common kinds of PCE polymers, namely methacrylate ester (MPEG), methallyl ether (HPEG) and isoprenol ether (IPEG) based PCEs produced in four major manufacturing countries: EU-27, US, Japan and China. A cradle-to-gate approach was applied to estimate CO 2 emissions from raw materials extraction to PCE fabrication. On this basis, and depending on their chemical composition and country-specific electricity grid CO 2 emission factors, their carbon footprints were calculated. The results show a strong dependence on the kind of PCE, their structural design as well as the producing country. For all PCEs, the main components ethylene oxide, unsaturated acids (methacrylic/acrylic acid) and NaOH were found to be mainly responsible for the entire CO 2 footprint. The average total CO 2 emissions of the three kinds of PCEs vary between 2.98 ± 0.54 kg CO 2 /kg (MPEG), 2.48 ± 0.48 kg CO 2 /kg (HPEG), and 2.40 ± 0.47 kg CO 2 /kg (IPEG). Evidently, MPEG PCEs reveal the highest footprint which is owed to methacrylic acid whereas HPEG and IPEG PCEs contain acrylic acid. The range of total CO 2 emissions is caused by significant differences in the carbon footprints of the electrical grids in various countries. An impact study revealed that at common field dosages the contribution of PCEs to the CO 2 balance of a standard concrete (CO 2 footprint ∼ 300 kg CO 2 /m3) varies between approx. 3 and 22 kg CO 2 /m3 in Europe, with ready-mix type PCEs contributing more than precast concrete PCEs. Furthermore, it is demonstrated that the CO 2 footprint of PCE superplasticizers can be reduced by almost 80% if predominantly renewable energy is used in the chemical industry. [Display omitted] • CO 2 footprint of PCE superplasticizers (MPEG/HPEG/IPEG) used in concrete studied. • Total CO 2 emission dependent on PCE chemistry/composition and producing country. • Highest CO 2 emission for MPEG PCE: methacrylic acid and EO major contributors. • Thermal energy generation and grid electricity responsible for most of CO 2 emission. • Utilizing renewable energy can reduce CO 2 footprint of PCE significantly. [ABSTRACT FROM AUTHOR]

Biogas upgrading through CO 2 conversion by hydrogenotrophic methanogenesis is receiving an increasing attention worldwide because of the demand for renewable natural gas. Herein, a holistic and statistical study of the operation conditions, driving forces, performances, and potential implementation of biogas upgrading via biological CO 2 conversion was conducted. Based on a systematic review and meta-analysis of 46 existing publications that were selected from 1475 papers, we have compiled a global dataset of CO 2 bioconversion biogas upgrading, encompassing 308 study cases. Subsequently, we employed a rigorous analytical framework incorporating data processing and mixed effects linear regression analysis to examine the dataset. This analysis revealed a significant positive relationship between the H 2 :CO 2 ratio and the methane percentage in the upgraded biogas when using the study as a random effect. Furthermore, we performed meta-analysis on observations taken when the ratio was close to 4:1 and found that ex situ reactors (91.93% [88.11%, 95.75%]) can perform better than in situ reactors (84.74% [80.69%, 88.80%]). No evidence of differential performance was found based on the present dataset between different temperature regimes or operation modes. Those findings establish a database that will contribute to a deeper understanding of the biogas upgrading via biological CO 2 conversion. [Display omitted] • Biogas upgrading can produce grid-level renewable natural gas. • A comprehensive global meta-analysis focuses on biological CO2 conversion. • The H 2 :CO 2 ratio is positively correlated with the biomethane percentage. • Ex-situ reactors outperform in-situ reactors based on meta-analysis of observations. [ABSTRACT FROM AUTHOR]

Food production is an important source of anthropogenic greenhouse gas (GHG) emissions. Quantifying the carbon footprint of all the major food categories in different continents is critical for accurately evaluating various aspects of GHG emissions from food production on a continental and global scale. Such information, however, is lacking. Thus, we conducted a meta-analysis of plant-based and animal-based food production in all continents comprehensively using 5353 carbon footprint values from 524 published papers and calculated GHG emissions from food production (system boundary is from cradle to farm gate) at the continental and global scale. Our results indicate that the average carbon footprint of plant-based foods amounts to 0.66 kg CO 2 -eq kg−1, which is only 10.7% of animal-based foods (6.15 kg CO 2 -eq kg−1). The carbon footprint of plant-based food in Asia and Europe is 8.9%–184% higher than that of other continents. Africa has the lowest carbon footprint for plant-based foods, owing to its low agricultural input and limited crop management. However, the carbon footprint of animal-based foods in Africa and Asia is 2.5%–150% higher than that of other continents, with North America and Oceania recording the lowest. Total annual GHG emission from global food production reached 8125 Mt CO 2 -eq, with grains, meat, and milk together accounting for 70.8%. Asia, owing to its large production, emerged as the largest emitter, accounting for 55.4% of global GHG emissions. It was followed by Europe (16.3%) and North America (10.5%), while Africa, South America and Oceania together emit 17.8%. In summary, our study presents the most comprehensive account of the carbon footprint of food production at the continental and global scale to-date, which will help develop strategies and policies to reduce GHG emissions at various levels such as geographical regions, food and nutrition security, resource availability and resource use. • Plant-based food carbon footprint (CF) < 89% than that of animal-based food. • Plant-based food CF in Asia and Europe up to >184% than that of other regions. • Animal-based food CF in Africa, Asia up to >150% than that of other regions. • Global food production GHG emission is 8125 Mt CO 2 yr−1. • Asia emits 55% of global food GHG emissions. [ABSTRACT FROM AUTHOR]

With rapid urbanization and industrialization, the number of light-duty gasoline vehicles (LDGVs) in China has continued to grow rapidly, leading to a significant increase in traffic pollution. Therefore, it is essential to accurately calculate the emission of LDGVs for air quality monitoring and management. Fortunately, Motor Vehicle Emission Simulator (MOVES) is a sophisticated model for estimating mobile source emissions with good prediction accuracy. However, the parameters of MOVES are based on the field tests in the US, which is worth exploring whether MOVES can be applied to other countries. Hence, in this paper, we used the portable emission measurement system (PEMS) to conduct real driving emission (RDE) tests of LDGVs, aiming to explore the possibility of the MOVES application in China. Based on the field tests, we modified basic parameters in the MOVES model, but unsatisfactory prediction performance was obtained. Existing research on improving MOVES performance mainly involved new binning of operating modes, but these methods had limited improvements. Though studies have also used machine learning methods for predicting LDGV emissions, they lacked comparison and integration with the MOVES model. To further improve the prediction accuracy, we proposed a novel road vehicle emission model that integrated the machine learning method and the MOVES to predict the road-level emission rates of NO and CO 2 emissions of LDGVs. In addition, we employed the Boruta algorithm to capture the key influencing factors and promote prediction performance. The enhanced model outperformed MOVES and achieved higher R2 values. On average, the improvement for CO 2 was 0.132, and for NO, it was 0.261. This work will provide references for MOVES improvements in practical scenarios and better predict pollutant emissions for LDGVs using limited resources of field tests in cities outside the US. • Integrating engine characteristics with the MOVES model can improve model performance. • Integrating machine learning with MOVES performs well in prediction of vehicle CO 2 and NO emission. • The proposed emission model provides a possibility for calculation rather than costly an experiment in countries outside the USA. [ABSTRACT FROM AUTHOR]

• The thermodynamics and reaction stoichiometry of the proposed design. • The mass balance for the system proposed in the paper. • The heat and fuel needs implicit in the proposed system. • The feasibility of the proposed gas separations and of using the BCNF double perovskite for decomposition of CO 2 at a realistic scale. [ABSTRACT FROM AUTHOR]

Life cycle indicators are essential for supporting decisions to decarbonize the construction sector. However, the use of such indicators remains limited in the construction industry, particularly in developing countries, partly because of their complexity, high cost, and fragmented life cycle assessment (LCA) tools. Therefore, we have developed the Information System for Environmental Performance in Construction (Sidac) to change this scenario. The system applies a streamlined LCA approach for assessing the cradle-to-gate embodied energy and CO 2 emissions of construction products. This online system includes all functionalities to consistently calculate, verify, communicate, and benchmark life cycle indicators. Based on primary data, the system is intended to facilitate the calculation and disclosure of life cycle indicators for construction products. This paper presents the principles and primary functionalities of this system. The first version of the system database contains generic data for 86 Brazilian construction products and 40 basic inputs, including electricity and fuels, and it is ready to receive manufacturer-specific data. By addressing barriers to assessing life cycle indicators of construction products, Sidac represents an important step towards the mainstream consideration of these indicators in the Brazilian construction value chain. This system can aid public policy in promoting low-carbon construction by providing a centralized and reliable environmental performance information system. Moreover, the development of Sidac is aligned with the trend of increasing digitalization and simplification of LCA. This system can serve as a model for developing similar simplified tools to accelerate the adoption of life cycle thinking in other countries and sectors. [Display omitted] • Reducing construction embodied carbon requires life cycle indicators of products. • Life cycle assessment complexity renders assessment of these indicators difficult. • Sidac focuses on calculating the embodied energy and carbon of products. • The system allows to calculate, verify, and communicate life cycle indicators. • Sidac can mainstream environmental performance declaration in construction. [ABSTRACT FROM AUTHOR]

Over hundreds of years, the global coal mining has created 24.236 billion cubic meters of underground goaf, which not only wastes billions of square meters of land resources but also poses significant safety hazards and environmental risks. Combining the treatment of mined-out areas with carbon dioxide (CO 2) storage can provide the new idea for solving the above problems in a low-carbon way. Therefore, based on an analysis of the status of mined-out areas and CO 2 storage principles, this paper proposes a method of using high-water materials to solidify supercritical CO 2 and fill mined-out areas. The feasible, safety and carbon fixing capacity of using high-water materials to solidify CO 2 and fill mined-out areas has been proved by theoretical analysis and indoor experiment. Combining the estimated underground mined-out area space of major coal-producing countries globally, proving that solidifying and sealing CO 2 in mined-out areas has significant application prospects. Finally, the issues and technical difficulties faced in promoting the use of high-water material to solidify supercritical CO 2 and fill mined-out areas are pointed out. The research results have important significance for major coal-producing countries worldwide to achieve "carbon peak and carbon neutrality". [ABSTRACT FROM AUTHOR]

This paper investigates the decoupling of carbon dioxide (CO 2 ) emissions from agricultural economic growth in 30 Chinese provinces from 1997 to 2014. First, CO 2 emissions from agricultural production activities, farming, and livestock husbandry are computed. Then, this paper explores the spatial and temporal heterogeneity of CO 2 emissions and their intensity in China’s agricultural sector. Finally, this paper compares decoupling of China’s agricultural CO 2 emissions from agricultural output value across different regions and years. The results indicate that fertilizer, in-season rice cultivation, and cattle generated the most CO 2 emissions in the categories of agricultural production activities, farming, and livestock husbandry, respectively. The results also show that East China covered more periods of the strong decoupling of CO 2 emissions from agricultural output value between 1997 and 2014. To decrease CO 2 emissions, this paper suggests imposing a higher value-added tax on fertilizer producers, while waiving value-added tax for organic fertilizer and substituting animal manure for conventional fertilizers where possible. [ABSTRACT FROM AUTHOR]

The accurate calculation of CO 2 emissions in every province in China is the basis for developing regional energy policies. There is a huge fossil-fuel reserve and production capacity in western China, whereas their underdeveloped social and economic status means that there is lower demand. The more developed eastern coastal regions of China show dynamic economic momentum and, hence, higher energy demand. Based on the carbon emission flows in network theory, this paper proposes an approach to recalculate provincial CO 2 emissions from the perspective of secondary energy consumption. This approach attributes CO 2 emissions to final energy consumers after considering cross-provincial secondary energy trading, especially cross-provincial electric power trading in the regional power grid. Given the uneven distribution of energy resources and the imbalance of energy consumption among regions, cross-provincial secondary energy trading in China is significant, especially in the power industry. By adopting the approach proposed in this paper, the provincial carbon intensity and the corresponding energy policy can be modified to make energy end users pay rather than the primary producer. [ABSTRACT FROM AUTHOR]

Mexico is an important iron and steel manufacturer; it is the 13th largest steel producer in the world. The Mexican iron and steel industry is first in energy consumption for industrial energy use, representing 14.3% of the total industrial final energy consumption and a similar share of related carbon dioxide emissions. The aim and novelty of this paper is to estimate both the energy intensity and CO 2 intensity of the Mexican iron and steel industry in 2010 based on defined system boundaries and an international comparison methodology and to compare the energy intensity of Mexican with those the US and China based on a literature review. The boundaries consider energy consumption for all coke making, pelletizing, sintering, iron making, steel making, steel casting, hot rolling, cold rolling, and processing, such as galvanizing or coating. They also include energy use for net imported pig iron, direct-reduced iron, pellets, lime, oxygen, ingots, blooms, billets, and slabs. Under these boundary conditions, the Mexican iron and steel industry was shown to be more energy efficient and less carbon intense than those the U.S. and China. The reasons for this efficiency are mainly the large shares of the electric arc furnace route (69.4%) and continuous casting (100%) in production and the large share of natural gas in the fuel mix. This paper highlights the importance of the definition of boundaries and clear methodologies to analyse the iron and steel energy efficiency. [ABSTRACT FROM AUTHOR]

The contribution of non-metallic sector to global CO 2 emissions is increasing. However, there are very few studies on non-metallic sector CO 2 emissions from international comparative perspective. This paper proposes an integrated model employing LMDI (Logarithmic Mean Divisia Index) decomposition technique and TOPSIS (the Technique for Order Preference by Similarity to Ideal Solution) method to contribute to the existing literature by filling the gap that the drivers of aggregate and national level non-metallic sector CO2 emissions and its impacts on CO2 emissions reduction have not been estimated by relevant models. First, we analyze drivers of non-metallic sector CO 2 emissions in BRIC countries and G7 countries using LMDI decomposition method. Second, we evaluate the low-carbon development of non-metallic sector in the 11 major economies from a comprehensive viewpoint of main drivers using TOPSIS assessment model. Finally, based on the results of the model, this paper presents some implications for the non-metallic sector CO2 emissions reduction and low-carbon development. [ABSTRACT FROM AUTHOR]

This paper investigates various alternatives for the application of CCS at a cement plant which is one of the focus site for CCS deployment in Norway. A matrix consisting of nine CCS alternative chains is analysed in order to quantify cost reduction potentials across the CCS value chain based on an in-house techno-economic assessment methodology and tool called iCCS. In particular, the paper quantifies the strong cost reduction potential of second generation capture technologies and transport technology selection. CO 2 EOR is also identified to have a strong potential to reduce the overall CCS cost, however the cost benefits are strongly dependent on the oil value and the considered EOR injection period. The impact of the inclusion of CO 2 capture and conditioning in the cost of cement shows that public financial support will be required to ensure that the plant remain competitive under current cement market price. Finally, comparison of the full-scale capture versus part-scale capture shows, in this case, that the economies of scale are nearly compensated by the additional steam cost, therefore limiting the interest for full-scale implementation. However, joint deployment with the two other CCS potential sites in Norway (Yara and Klemenstrud) may bring more synergies. [ABSTRACT FROM AUTHOR]

Energy is needed in all sectors: industrial, domestic, commercial, transportation, power generation. Fossil fuel has been the main source of energy since decades. Due to rising greenhouse gases (GHG) emissions, the energy mix in many countries are shifting towards alternative energy sources, such as renewable energy and nuclear. At the same time, energy demands should also be managed and minimised to curb the rising GHG. Transitioning towards cleaner energy supply may also take time due to economic, political, technology readiness and public acceptance reason. A faster solution is to sequestrate CO 2 especially through CO 2 capture, utilisation and storage technologies. This paper presents an overview of the Journal of Cleaner Production Special Volume for the 18th conference “Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction (PRES 2015)”. The paper discussed issues, methods and solutions to achieve cleaner energy. The review has been written from the perspective of the supply side management, demand side management or end-of pipe management. The content of the Special Volume also includes cleaner energy planning, policies and education. The Special Volume reviews various ideas and discussion from authors all over the world and also provides some directions for future studies. [ABSTRACT FROM AUTHOR]

The cement manufacturing industry, a resource- and energy-intensive sector, took up more than 15% of total greenhouse gas emissions in China, thus finding a clean technology option for sustainable development is essential. CO 2 curing has emerged as a promising novel method for large-scale carbon sequestration and mechanical properties improvement of cement-based composites. Currently, a body of related works is mainly investigated in the laboratory, and understandings of the behaviors of CO 2 -cured cement-based composites are still less than complete, including, 1) the CO 2 storage potential has plenty of room for improvement due to the influence mechanism of variables factors remains unclear; 2) previous evaluations were mostly based on the subsets of individual result rather than an integrated dataset; 3) whether CO 2 curing is suitable for the manufacturing process of reinforced concrete. Therefore, this paper presents a comprehensive overview covering a wide range of parameters as well as fabrication, mechanical (compressive strength), and environmental (CO 2 uptake value) performances on the basis of a correct understanding of the differences between active and passive carbonation reactions. Notably, the influences of critical factors, including those less understood, e.g., types of curing setup (flow-able, enclosed, and others), components of binder, and aggregate/binder ratio, are also analyzed and the corresponding mechanisms discussed to achieve satisfied curing efficiency. Besides, corrosion-related challenges are also be pointed out to convince the widespread acceptance of this technology. Finally, based on this paper, limitations of existing research are identified and future scope on CO 2 curing regime is proposed. • 170 studies related to CO 2 /carbonation-cured cement-based composites are analyzed. • The differences between active/passive-carbonation together with reaction mechanisms are expounded. • Fabrication and influence factors on engineering and environmental properties are systematically reviewed. • CO 2 -cured cement-based composites exhibit excellent resistance to aggressive conditions. • The challenges and opportunities in the CO 2 curing method are innovatively discussed. [ABSTRACT FROM AUTHOR]

Carbon dioxide emissions pricing is employed as an approach to mitigate climate change. To analyze the impact of carbon prices on the metal mining industry, this paper presents a new block-based carbon dioxide emissions estimation model to assess the carbon dioxide emissions and carbon intensity in varying carbon prices, by employing the engineering-based inputs from life cycle of mineral production. Such engineering-based data of an iron case is provided to test the impact of carbon prices on mining projects. The results indicate that the negative impact of carbon prices on the profit of mining projects is more sensitive in low minerals prices, especially for underground method. On the other hand, carbon price rising facilitates the mitigation of carbon dioxide emissions, by lowering the ratio of excavated waste rocks to mined-out raw ore, which varies linearly with the emissions. The carbon dioxide emissions in the studied case decrease from 39.92 kg carbon dioxide eq per ton to 21.50 kg carbon dioxide eq per ton, and from 51.02 kg carbon dioxide eq per ton to 42.80 kg carbon dioxide eq per ton, for surface and underground method, respectively. The results of carbon intensity show that it keeps increasing due to carbon price rising, until the mining boundaries are optimized based on the increased carbon price. Image 1089 • Block-based carbon dioxide emissions estimation model is introduced for metal mines. • The projects' profit is more sensitive to carbon prices in low minerals prices. • Carbon dioxide emissions vary linearly with the ratio of excavated rocks to raw ore. • Rising carbon price increases carbon intensity before mining boundary is optimized. [ABSTRACT FROM AUTHOR]

As the basic sector providing basic service and promoting economy development, the increment demand of transport sector has brought much more pressure on the environment. Beijing-Tianjin-Hebei region is the representative region of the advanced region of China and it is significant to analyze how to achieve the low-carbon transport development in Beijing-Tianjin-Hebei region, meanwhile provide reference of green development for other regions. Using the panel data from 1995 to 2016, the paper analyses the driving factor of carbon dioxide emissions from transport sector with two different analytical methods. The results of LMDI show that transportation energy intensity and economic effect is the main factor increasing the carbon dioxide emissions and the contributing factors to the carbon dioxide emissions reduction in the transport sector are the energy structure effect, the freight turnover of unit industrial output effect and the industrialization effect. In different subclasses divided by different threshold variables, industrialization has the positive impact while the coefficients vary, which indicates that appropriate development policies should be formulated in light of the development characteristics of different regions. [ABSTRACT FROM AUTHOR]

As global warming continues to worsen, the balance between carbon dioxide emissions and economic growth has received increasing attention and carbon-reduction comes to be an urgent task in many countries. In literature, various regression models have been developed to investigate the relationship between carbon dioxide emissions and economic growth, such as the inverted U-shaped EKC model, inverted N-shaped model, etc., which play critical roles in analyzing the relationships. Existing studies suggest that some countries follow similar models to describe the relationships, while others employ different ones. Regarding the interplay between carbon dioxide emissions and economic growth, there lacks a cluster analysis to systematically uncover the similarity of countries that employ models more similar to each other than to the countries in other clusters. In this paper, a novel clustering approach is proposed to identify clusters of 67 countries from the spatial, temporal, and descriptive dimensions. Unlike the traditional clustering technique, in which clusters are determined by geometric distances, the clusters in this research are obtained based on the differences between the fitting models of the countries in each cluster. The first step of the approach is to find clusters of countries sharing similar models in a given year based on the symbolic regression method, and the second step is to determine the countries that frequently cooccur in the same cluster by the Apriori algorithm. The results present two high-order clusters with different dynamic features during the period between 1971 and 2010. One high-order cluster mainly consists of countries in higher level of income while the other contains lower income level countries, and the carbon intensities of the two high-order clusters have distinct differences. The findings suggest that the countries within the same cluster could learn more lessons from each other, while countries belonging to different clusters should not be examined together indiscriminately. Several policy implications are provided, which may inform decision-making for policymakers when choosing proper learning objects and help researchers with designing optimal models for specific countries. ● Conduct a cluster analysis of the nexus between CO 2 emissions and economic growth. ● A novel data-driven clustering approach based on symbolic regression is proposed. ● Intelligently discover the underlying models and extract the dynamic clusters. ● Countries that frequently cooccur in the same cluster are identified. ● Environmental policymaking is not "one size fits all" and clusters will be helpful. [ABSTRACT FROM AUTHOR]

Abstract Considering the game among enterprises, this paper studies low-carbon diffusion problem from the perspective of network characteristics and consumers' environmental awareness. Under the scenario of heterogeneous environmental awareness, the low-carbon diffusion model based on evolutionary game theory and complex network theory is established to describe the game of enterprises' low-carbon strategy adoption in the network and the strategy learning among network neighbors. Simulation analysis in complex networks reveals the roles of network characteristics such as average degree, degree distribution and consumers' environmental awareness played in low-carbon diffusion. The results show that increasing the connections among enterprises in the industry can help the spread of low-carbon strategies. However, the diffusion potential of the network is largely exploited when the average degree exceeds 6, and the low-carbon strategies spread slowly afterwards. A certain percentage of green consumers drives this certain percentage of enterprises to implement low-carbon strategies approximately in equilibrium which indicates that the low-carbon diffusion rate can reach 100% when all consumers become green consumers who are willing and able to pay for low-carbon premium. White customers contribute to the spread of low-carbon strategies, but the promotion effect is not as good as green customers. The small-world (SW) network is more efficiently than the scale-free (SF) network in low-carbon diffusion when consumers' environmental awareness is low. However, when the consumers' environmental awareness is higher than a certain value, the SF network has a higher diffusion rate in equilibrium than the SW network. Highlights • The evolutionary game model on low-carbon diffusion in complex network context is constructed. • The characteristics of complex network such as average degree and degree distribution affect low-carbon diffusion. • Green customers are the determinants of low-carbon diffusion and white consumers are the icing on the cake. • The priority of low-carbon diffusion in SW network and SF network relates to customers' environmental awareness. [ABSTRACT FROM AUTHOR]

Abstract As a core component of the emission trading scheme (ETS), the initial allocation of carbon quotas is extremely important. Currently, most allocation methods mainly focus on the realization of a single performance goal, which will result in conflicts between different levels of participants. To overcome this limitation, a bi-objective programming model (BPM) with two sub-objective functions of abatement costs and carbon assets is proposed. Meanwhile, cost-oriented model (CM) and asset-oriented model (AM) are implemented as comparison approaches that represent the minimization of regional abatement costs and the maximization of individual interests, respectively. The empirical results of the Pearl River Delta (PRD) region reveal that BPM is the most efficient and feasible approach to some extent. More precisely, BPM can motivate the enthusiasm of all participants while optimizing abatement costs. With the increase of regional total quotas, the advantage of BPM becomes more and more prominent. The contribution of this paper is to present a novel method for carbon emission quota allocation, which fills the gap in the existing literature. Furthermore, the proposed method that can be deployed in other similar regions assists policymakers in enacting an effective emission reduction policy and in better understanding the objectives of economy, energy and environment. [ABSTRACT FROM AUTHOR]