Amount Of CO2 Emissions Research Articles

Techno-economic, environmental, and exergetic evaluation of a novel isopropyl n-phenylcarbamate production process through non-reductive conversion of CO2

The conversion of carbon dioxide (CO2) into valuable chemicals has emerged as a prominent research field. This study attempts to uncover the rigorous design and comprehensive analysis of an innovative process that produces Isopropyl N-phenylcarbamate (IPPhCM) through direct synthesis involving CO2, 2-Propanol (IPA), and phenylamine (PHAM). The reaction system utilizes CeO2 as a catalyst and 2-Cyanopyridine (2-CP) as a chemical dehydrant. In general, this work presents alternative designs in a rigorous manner, with different combinations of conversion and yield. It also evaluates various strategies, such as heat integration, thermal coupling, and the addition of a co-reactant, to enhance the efficiency of the system. Based on the results, the configuration designed with a 92% yield of IPPhCM and incorporating both dividing-wall columns and direct heat integration was determined to be the best scenario. The corresponding minimum required selling price (MRSP) for IPPhCM is 1.996 USD/kg (at a 15% internal rate of return, measured without considering the cost of 2-CP), and the amount of CO2 emission per unit amount of product formed is + 0.075 kg/kg. However, the overall exergy efficiency of this process is only 42.7%. The main reason is the formation of mixtures that are difficult to separate, involving side products such as isopropyl picolinate (IPP), diisopropyl carbonate (DIPC), and others. To enhance the scheme, retrofitting it by adding ammonia to the reaction section enables the conversion of IPP and DIPC into valuable and separable by-products, namely 2-picolinamide (2-PA) and isopropyl carbamate (IPCM). This arrangement significantly enhances the exergy efficiency to 71.8% and reduces the MRSP to 1.759 USD/kg, at the cost of a slight increase in CO2-e to 0.118 kg/kg. With these results, the regeneration of byproducts can make the entire process more appealing and sustainable.

Energy Assessment of Different Powertrain Options for Heavy-Duty Vehicles and Energy Implications of Autonomous Driving

Heavy-duty vehicles (HDVs) are responsible for a significant amount of CO2 emissions in the transport sector. The share of these vehicles is still increasing in the European Union (EU); nevertheless, rigorous CO2 emission reduction schemes will apply in the near future. Different measures to decrease CO2 emissions are being already discussed, e.g., the electrification of the powertrain. Additionally, the impact of autonomous driving on energy consumption is being investigated. The most common types are fuel cell vehicles (FCEVs) and battery-only vehicles (BEVs). It is still unclear which type of powertrain will prevail in the future. Therefore, we developed a method to compare different powertrain options based on different scenarios in terms of primary energy consumption, CO2 emissions, and fuel costs. We compared the results with the internal combustion engine vehicle (ICEV). The model includes a model for the climatization of the driver’s cabin, which we used to investigate the impact of autonomous driving on energy consumption. It became clear that certain powertrains offer advantages for certain applications and that sensitivities exist with regard to primary energy and CO2 emissions. Overall, it became clear that electrified powertrains could reduce the CO2 emissions and the primary energy consumption of HDVs. Moreover, autonomous vehicles can save energy in most cases.

Das neue Gebäudeenergiegesetz

Abstract The reform of the Buildings Energy Act is intended to increase the share of renewable energies in the heat sector. But the proposed measures (among which the promotion of electric heat pumps figures prominently) are ecologically ineffective. They will not decrease the total amount of CO2 emissions in Germany, which are already subject to the caps of national and European emissions trading systems. Installing heat pumps in the building stock will require high investments and thus make any emission reductions in the heat sector much more expensive than in other sectors. Furthermore, due to its command-and-control approach, the bill is incompatible with the central principles of the German Social Market Economy.

Parametric BIM-based life cycle assessment framework for optimal sustainable design

The construction sector is liable for a sizable amount of CO2 emissions and waste. Life Cycle Assessment (LCA) is considered one of the crucial tools that aids in evaluating the impacts of construction emissions. This research aims to quantify the life cycle impacts of the initial and recurrent embodied emissions, operating and reuse/disposal emissions, and utilizing Building Information Modeling (BIM) for a more holistic life cycle approach. The research proposes a parametric BIM-based LCA framework for quantifying the environmental impacts and evaluating the effects of material selection for both embodied and operating emissions. In addition, it considers the different reuse scenarios and percentages and their effect on both the embodied and operating impacts. The proposed framework consists of five main modules: data acquisition module, operating and embodied emissions module, life cycle assessment module, optimization module, and decision-making module. This parametric assessment can be applied for both the conventional and circular approach impacts. For the decision-making process, the resulting emissions are optimized utilizing the Non-dominated Sorting Genetic Algorithm II (NSGA-II) and evaluated through an LCA and Data Envelopment Analysis (DEA) methodology for the material selection. A case study of a residential villa in Cairo is worked out to illustrate the key features of the proposed framework. This assessment analyzes the building materials’ characteristics and efficiency investigating the external walls, internal walls, floors, roofs, and windows design possibilities, and uses visual programming to control the resulting emissions for a more flexible approach. By comparing the integrated LCA and DEA models three optimum design solutions, the conventional approach develops design solutions of higher embodied Global Warming Potential (GWP) than the circular approach. However, it develops lower operating GWP with better applied U-values. The circularity approach employment has reduced the efficiency of the operating GWP due to utilizing materials with high heat transmittance ability.

Effect of Class F Fly Ash on Strength Properties of Concrete

Reducing the amount of CO2 emissions in the environment is one of the priorities of the EPA and other environmental agencies. A way to reduce CO2 emissions is by using fly ash in the concrete industry. Aside from environmental benefits, fly ash has numerous quality advantages; some of the positive effects were recognized earlier; however, in this research, the objective is to replace cement with a different percentage of class F fly ash with a low CaO content to produce sustainable concrete. Laboratory tests were performed to examine the rational percentage of cement replaced by class F fly ash in ordinary concrete C–25/30 and high-performance concrete C–50/60. In total, twelve different mix designs were prepared to examine consistency, setting time, shrinkage, and compressive strength in different periods of curing for more than 600 days. Using recycled material in new buildings still has some obstacles, but the future of construction must be green, so this research indicates that the objective of producing ordinary and high-performance concrete was achieved by replacing 30% of cement with class F fly ash. Doi: 10.28991/CEJ-2023-09-09-011 Full Text: PDF

A review of Znln2S4‐based photocatalysts for producing hydrogen by water splitting under visible light: Fundamentals and recent advancements

AbstractHydrogen (H2) is a clean energy carrier widely used in oil refineries, fertilizers, chemicals, and steel manufacturing. Presently, the majority of H2 is produced from either steam methane reforming of natural gas or coal gasification; however, these technologies result in a massive amount of CO2 emission. Alternatively, the use of photocatalysts for producing H2 via water splitting is an eco‐friendly and sustainable approach, among which the selection of highly efficient, stable, and cheap photocatalysts is the key. In this review, Znln2S4‐based photocatalysts are thoroughly described in terms of the fundamentals and thermodynamics of water splitting, fabrication methods, and different heterostructure photocatalytic systems. After this, recent developments in the large‐scale implementation of photocatalytic reactors are discussed. Finally, a summary of future research directions and major conclusions is provided. With proper modification, such as heterojunction systems and the selection of proper fabrication methods, Znln2S4‐based photocatalysts could be superior materials for water splitting. In short, this review article could offer meaningful and useful insights and guidance for the development of Znln2S4‐based photocatalysts in water splitting for producing H2 under visible light.

Design and Implementation of Renewable Hydrogen-Based System for Social Housing Decarbonization

The energy transition towards a decarbonized economy requires focused and ambitious policies that must be taken through the agreement of governments, stakeholders, and private companies. The intermittency of renewable energy sources (RES) makes it necessary to implement energy storage systems (ESS) that allow for an uninterrupted supply of low-carbon power. Energy generation and consumption activities are responsible for 75% of global CO2 emissions. Particularly, energy use in commercial and residential buildings is the third major contributor after industry and agricultural activities 1. In this context, hydrogen as an energy vector facilitates and enhances RES penetration in the energy mix. Moreover, it can be employed as a fuel or commodity to obtain other chemical compounds 2. Hence, hybrid renewable hydrogen-based systems (RHS) can play a key role in buildings decarbonization 3. On top of that, green hydrogen may tackle other problems such as energy poverty faced by the most vulnerable and disadvantaged citizens 4.In this context, the SUDOE ENERGY PUSH project proposes an innovative solution for the overall management of social housing located in the regions of southwestern Europe to increase the energy efficiency of public buildings and improve the living standards of vulnerable citizens. Through passive renovation, RES, and BIM methodology, it aims at reducing the consumption and emissions of buildings and at improving the comfort of the inhabitants, overcoming the risks of energy poverty. In this context, a pilot plant combining RES and hydrogen technologies has been implemented in a social housing in Cantabria (Spain) to demonstrate the feasibility and benefits of the system. This demonstration is aimed at achieving energy self-sufficiency of the house throughout the year while saving remarkable amounts of primary energy and CO2 emissions. The primary source of the system will be solar photovoltaic (PV) energy. To combat PV intermittency and harness the periods with energetic surpluses, different energy storage systems (ESS) have been installed within the pilot plant: lithium-ion batteries for short-term energy storage and hydrogen-based technologies for seasonal energy storage. Furthermore, a compressor has been included to reduce the hydrogen storage volume and a programmable logic controller (PLC) rules the operation of the configuration based on the state of charge of the batteries, so that the PLC decides which equipment operates at what time. Finally, the pilot plant is continuously monitored to optimize the control algorithm and enhance the overall performance of the implementation.To carry out the design of the system, an hourly load profile has been built by compiling real consumption data from the smart meter of a home during a year to obtain an accurate hourly load demand. Subsequently, meteorological resources of the location have been considered to obtain an hourly renewable generation profile. Furthermore, equipment costs and characteristics, apart from compressor energy demand have been taken into account. The main objective is to reduce the system size and the resulting levelized cost of energy, as well as increasing the overall efficiency of the system 5.According to the simulated operation of the pilot plant, the home can be disconnected from the grid, saving up to 7,000 kWh per year of primary energy from the grid, 1,000 kg per year of CO2 emissions while consuming 100% clean electricity and more than 600 € per year in electricity bills. As per November 2022, more than 3,500 kWh of primary energy, more than 500 kg of CO2 and more than 400 € have been saved in a six month period, showing a great correlation between the simulation and the real outcomes obtained during the normal functioning of the plant. Acknowledgment This research is being supported by the Project ENERGY PUSH SOE3/P3/E0865, which is co-financed by the European Regional Development Fund (ERPF) in the framework of the INTERREG SUDOE program, as well as the project, “HYLANTIC”-EAPA_204/2016 within the framework of the INTERREG ATLANTIC program. Furthermore, the Spanish Ministry of Science, Innovation, and Universities is also supporting this investigation through the projects PID2021-123120OB-I00, TED2021-129951B-C21 and PLEC2021- 007718 References 1 H. Ritchie and M. Roser, CO₂ and Greenhouse Gas Emissions, https://ourworldindata.org/co2-and-other-greenhouse-gas-emissions.2 I. Staffell, et al., Energy Environ. Sci., 2019, 12, 463–491.3 V. M. Maestre, A. Ortiz and I. Ortiz, Renew. Sustain. Energy Rev., 2021, 152, 111628.4 V. M. Maestre, A. Ortiz and I. Ortiz, J. Chem. Technol. Biotechnol., 2022, 97, 561–574.5 V. M. Maestre, A. Ortiz and I. Ortiz, J. Energy Storage, 2022, 56, 105889. Figure 1

Low‐carbon sustainable development driven by new energy vehicle pilot projects in China: Effects, mechanisms, and spatial spillovers

AbstractThe transport sector, as one of the major carbon‐emitting industries, is under great pressure to reduce carbon emissions against the backdrop of low‐carbon sustainable development. The new energy vehicle (NEV) pilot projects provide an opportunity for China to make strides towards Dual Carbon targets. Based on the panel data of 277 cities in China from 2000 to 2019, this study acquires the time‐varying difference‐in‐difference (DID) method to evaluate the impact of NEV pilot projects on urban CO2 emissions, including the mechanisms, heterogeneity, and spatial spillover effect. The conclusions are as follows. The NEV pilot projects achieve co‐benefits in reducing the total amount and intensity of urban CO2 emissions. The mechanism analysis shows that the NEV pilot projects reduce CO2 emissions by improving energy consumption structure and increasing electric busses. For pilot cities with different resource endowments and traffic pressures, the carbon reduction effects in non‐resource‐based cities and license plate‐restricted cities are more effective. Moreover, considering the geographical distance factor, the NEV pilot projects only have spatial spillover effects on the intensity of CO2 emissions in neighboring cities. These results contribute to clarifying the carbon reduction potential of NEVs and providing references for other developing countries to carry out decarbonization in the transportation industry.

Hydrogenation of Carbon Dioxide to Methanol over Non-Noble Catalysts: A State-of-the-Art Review

The malignant environmental changes caused by the ever-increasing amount of anthropogenic CO2 emissions have been particularly prominent in recent years. To achieve carbon mitigation and carbon neutrality, CO2 hydrogenation to methanol is regarded as a promising and sustainable route. However, the development of catalysts with exceptional performance and the establishment of a clear structure–activity relationship remain formidable challenges. Considering the lack of a state-of-the-art review on the catalytic progress of CO2 hydrogenation to methanol over non-noble catalysts, we conducted a detailed review in terms of the thermodynamic analysis, catalytic development, and reaction mechanism. In this work, we mainly reviewed the latest research progress of different catalysts including Cu-based, In2O3-based, bimetallic, solid solution, and other catalysts. Meanwhile, we summarized the effects of the support materials, promoters, and preparation methods on the catalytic performance. In addition, we also summarized the possible reaction mechanisms of direct hydrogenation of CO2 to methanol. Overall, this work would be of importance for the researchers to obtain a comprehensive understanding of the design and development of efficient catalysts for CO2 hydrogenation to methanol.

Cofactor Metabolic Engineering of Escherichia coli for Aerobic L-Malate Production with Lower CO2 Emissions.

Escherichia coli has been engineered for L-malate production via aerobic cultivation. However, the maximum yield obtained through this mode is inferior to that of anaerobic fermentation due to massive amounts of CO2 emissions. Here, we aim to address this issue by reducing CO2 emissions of recombinant E. coli during aerobic L-malate production. Our findings indicated that NADH oxidation and ATP-synthesis-related genes were down-regulated with 2 g/L of YE during aerobic cultivations of E. coli E23, as compared to 5 g/L of YE. Then, E23 was engineered via the knockout of nuoA and the introduction of the nonoxidative glycolysis (NOG) pathway, resulting in a reduction of NAD+ and ATP supplies. The results demonstrate that E23 (ΔnuoA, NOG) exhibited decreased CO2 emissions, and it produced 21.3 g/L of L-malate from glucose aerobically with the improved yield of 0.43 g/g. This study suggests that a restricted NAD+ and ATP supply can prompt E. coli to engage in incomplete oxidization of glucose, leading to the accumulation of metabolites instead of utilizing them in cellular respiration.

The synergy effect through combination of the digital economy and transition to renewable energy on green economic growth: Empirical study of 18 Latin American and caribbean countries

Tremendous effects on the global economy in terms of economic, social and environmental costs remind us of the catastrophic consequences of climate change and global warming caused by CO2 emissions. Therefore, accelerating decarbonization of the global energy system should be put in place to curb large amount of CO2 emission from hydrocarbon energy sources on which the current global value chain of production heavily relies.This study focuses on analyzing the effects of renewable energy transition, the digital economy, and the synergy between them on green economic growth in 18 Latin American countries. To capture the multidimensionality of these transitions, the Renewable Energy Transition Index (RETI) and the Digital Economy Index (DEI) are developed using the Principal Component Factor (PCF) technique. The FixedEffect Panel Threshold Regression (FEPTR) substantiates that renewable energy transition has a significant threshold effect on economic growth and environmental sustainability depending on the level of income and carbon emissions. On the other hand, the Method of Moments Quantile Regression (MMQR) shows that both renewable energy transition and the digital economy have a significant positive impact on economic growth in all quantile groups. For the environmental sustainability, only renewable energy transition is found to have a positive impact in all quantile groups. From the synergistic effect perspectives, the CO2 emissions reduction is observed in both the low and middle quantile groups, but the economic growth promotion is only observed in a low quantile group.

Insights into CO2 activation and charge transfer in photocatalytic reduction of CO2 on pure and metal single atom modified TiO2 surfaces

Large amounts of CO2 emissions associated with expanded fossil fuel consumption have caused global warming and energy crisis. The photocatalytic reduction of CO2 is one of the most promising ways to solve these problems. However, some basic issues in CO2 photocatalytic reduction over pure and modified TiO2 surfaces, such as the transfer of photogenerated electrons, CO2 adsorption configuration with excess electrons, the mechanism of CO2 activation, still lack in-depth investigation and analysis. In this work, using density functional theory (DFT) calculations, we systematically calculated the transfer of photogenerated electrons, workfunction, CO2 adsorption energy, charge density difference, density of states (DOS), and CO2 dissociation energy barrier on different pure and metal single atom modified TiO2 surfaces. Based on these results, we further analyzed the effect of photogenerated electrons and metal single atoms on CO2 adsorption and activation, and identified the different behavior of photogenerated electrons on pure and metal single atom modified TiO2 surfaces. Finally, a synergetic effect of photogenerated electrons and loaded metal atoms is proposed, which is crucial in understanding CO2 photocatalytic reduction and designing efficient new photocatalytic materials.

Optimization Techniques For Low Energy Consumption In Green Cloud Computing

Computing in the cloud can assist businesses in shifting their focus to the development of solid business applications that will bring about genuine value to the businesses. Green computing, often known as environmentally sustainable computing, is the definition of green computing. It is a reference to the efforts that are made to maximise the usage of power consumption & energy efficiency while simultaneously minimising the cost & the amount of CO2 emission. To conduct a study on optimisation techniques & procedures that assist us in optimising low energy consumption & evaluating multiple parameters in order to obtain the desired output is the primary purpose of this research. Energy-Conscious Multisite Computation Offloading Techniques (EMOGC) for Green Cloud Computing is the methodology that was utilised throughout this project. Simulation & analysis are presented in The Energy-Conscious Multisite Computation Offloading Techniques for Green Cloud Computing in order to investigate time-efficient scheduling on multisite, which is responsible for optimising energy, time, & cost at the optimum time. This strategy seeks to finish the application within the allotted amount of time while also consuming as little power as feasible from the connected devices. According to the findings of this research, it is clear that the explored technique is effective in obtaining high throughput (HT) while simultaneously minimising the execution time, which in turn enhances the data rate in Green Cloud Computing (GCC).

The Adsorption Mechanism of Hydrogen on FeO Crystal Surfaces: A Density Functional Theory Study.

The hydrogen-based direct reduction of iron ores is a disruptive routine used to mitigate the large amount of CO2 emissions produced by the steel industry. The reduction of iron oxides by H2 involves a variety of physicochemical phenomena from macroscopic to atomistic scales. Particularly at the atomistic scale, the underlying mechanisms of the interaction of hydrogen and iron oxides is not yet fully understood. In this study, density functional theory (DFT) was employed to investigate the adsorption behavior of hydrogen atoms and H2 on different crystal FeO surfaces to gain a fundamental understanding of the associated interfacial adsorption mechanisms. It was found that H2 molecules tend to be physically adsorbed on the top site of Fe atoms, while Fe atoms on the FeO surface act as active sites to catalyze H2 dissociation. The dissociated H atoms were found to prefer to be chemically bonded with surface O atoms. These results provide a new insight into the catalytic effect of the studied FeO surfaces, by showing that both Fe (catalytic site) and O (binding site) atoms contribute to the interaction between H2 and FeO surfaces.

Metabolism and carbonate buffering drive seasonal dynamics of CO2 emissions from two German reservoirs

Biological metabolism drives much of the variation in CO2 in terrestrial ecosystems but does not explain CO2 oversaturation and emission in net autotrophic lakes and reservoirs. The unexplained CO2 could be attributed to the equilibria between CO2 and the carbonate buffering system, which is seldom integrated into CO2 budgets, let alone its interplay with metabolism on CO2 emissions. Here, we perform a process-based mass balance modeling analysis based on an 8-year dataset from two adjacent reservoirs with similar catchment sizes but contrasting trophic states and alkalinity. We find that in addition to the well-acknowledged driver of net metabolic CO2 production, carbonate buffering also determines the total amount and seasonal dynamics of CO2 emissions from the reservoirs. Carbonate buffering can contribute up to nearly 50% of whole-reservoir CO2 emissions, by converting the ionic forms of carbonate to CO2. This results in similar seasonal CO2 emissions from reservoirs with differing trophic state, even in low alkalinity system. We therefore suggest that catchment alkalinity, instead of trophic state, may be more relevant in predicting CO2 emissions from reservoirs. Our model approach highlights the important role of carbonate buffering and metabolism that generate and remove CO2 throughout the reservoirs on a seasonal scale. The inclusion of carbonate buffering could diminish a major uncertainty in the estimation of reservoir CO2 emissions and increase the robustness of aquatic CO2 emission estimates.

Will Trade Protection Trigger a Surge in Investment-Related CO2 Emissions? Evidence from Multi-Regional Input–Output Model

Current research has revealed that global trade promotes transnational investment and contributes to large amounts of CO2 emissions. Recently, trade protectionism has gradually emerged. This study aims to explore the effect of global trade protection on investment-related CO2 emissions. We construct an accounting framework for investment-related CO2 emissions under trade freedom and trade restriction based on the MRIO model for the first time, and investment-related CO2 emissions in 16 economies are determined in both trade freedom and trade restriction scenarios. The study uses normal trade and no-trade scenarios instead of free trade and restricted trade scenarios. Then, based on the comparison of the two scenarios, the effect of global trade protection on investment-related CO2 emissions is revealed from the three levels of country, section, and trade links. It is found that global trade protection would lead to an increase of up to 546.17 million tons in investment-related CO2 emissions under current trade structures. Transnational investment in the trade of end-stage intermediary goods contributed 81.6% of the total effect. In terms of countries, trade protection is quite disadvantageous to CO2 emission reduction in China and India, and their CO2 emissions would respectively increase by 105 million tons and 141.5 million tons compared to normal trade. The electricity, gas, and water supply sectors and the manufacturing sector are the main sectors for investment-related CO2 emissions. This study reveals the effect of trade freedom and trade protection on the environment of various countries from the viewpoint of investment-related CO2 emissions, which has important reference value for global CO2 emission reduction in the context of the evolving trade situation.

Effect of O2 transport membrane and CO2 capture membranes on the performance of the biomass-based power generation: An artificial intelligence based multi-objective optimization and techno-economic and environmental evaluation

One of the most important causes of global warming is the release of carbon dioxide (CO2) gas into the atmosphere due to the production of electricity to meet the global community's need for energy. The main goal of this research is to present a power generation system based on biomass gasification equipped with a membrane-based carbon capture system. In this system, a gasifier and an oxygen transport membrane (OTM) were coupled with each other to produce pure O2 as a gasification agent. Moreover, a three-membrane system is considered to separate CO2 from combustion gases coming out of the combined Brayton-Rankin cycle. The desired system has been carefully examined from a thermodynamic outlook. In the next step, the cost of electricity has been obtained by using a detailed economic study, taking into account the life of the employed membranes. Finally, by using artificial intelligence (AI)-based multi-objective optimization, the presented system has been optimized from the economic point of view and thermodynamic performance. The results of this research show that the use of OTM to produce pure oxygen as a gasification agent leads to a 53% improvement in the heating value of the produced fuel compared to the use of air (without OTM). Furthermore, the use of CO2 capture membranes (CCM) led to the reduction of annual CO2 emissions from 50.41 Mkg to 9.9 Mkg. According to the Pareto front, the results obtained from the minimization of the electricity cost and the maximization of the net power production showed that the minimum electricity cost and the maximum produced power were 0.4275 $/kWh and 7039 kW, respectively. It can be acknowledged that the optimization and the addition of the carbon capture system in the carbon tax of 303$/Tonne-CO2 (and more than that) not only can produce electricity at a lower cost, but also reduce the amount of CO2 emission from 50.43 million kilograms per year to of 6.9 million kilograms per year.

Geothermal Power Corridor- connecting the Middle East Countries

The Middle East economy and life depend on imports, be it food, water, or energy, despite each country in the region having enormous energy resources to exploit and reduce dependency on countries outside the region and develop a socioeconomic model of regional cooperation and synergy. An estimated 371 TWh of electricity available from geothermal energy resources can be utilized by these countries to support basic needs and be free from food-energy-water imports by sharing their energy resources. The total amount of CO2 emissions from these countries is currently 945 x 106 kg, so these countries can further earn about 92 million euros from carbon savings, by using geothermal energy along this corridor. This amount can be utilized for augmenting the energy supply from geothermal sources. In this work, the available geothermal resources are evaluated, and suggestions are made how this energy can be best utilized for peaceful existence and cooperation in the region.

CO2 Emission Allocation for Urban Public Buildings Considering Efficiency and Equity: An Application at the Provincial Level in China

China is currently recognized as the leading global energy consumer and CO2 emitter. A significant amount of carbon emissions can be attributed to urban public buildings. Establishing an equitable and efficient carbon emission allocation mechanism is a crucial step to meeting the ambitious targets in China’s 2030 carbon peak plan. In this study, we estimate the total amount of CO2 emissions from urban public buildings by 2030 and propose a preliminary scheme of carbon quota assignment for each province. By means of applying the zero-sum gains data envelopment analysis (ZSG-DEA) model, the carbon emission quotas allocation of urban public buildings in China’s 30 provinces is proposed, and the corresponding pressure to reduce provincial carbon emissions is analyzed. The results indicate that Qinghai has the lowest carbon emission rate (0.01%) for urban public buildings, while Guangdong has the highest (9.06%). Among the provinces, Jiangsu, Jiangxi, and Tianjin face the least pressure in reducing carbon emissions from urban public buildings. On the other hand, Hebei, Beijing, and Anhui are under great pressure to decrease carbon emissions. Notably, Hebei is predicted to have the highest emission reduction requirement of 95.66 million tons. In terms of pressures on carbon emissions reduction for urban public buildings, Jiangsu, Jiangxi, and Tianjin exhibit the least pressure. Hebei, Beijing, and Anhui are facing intense pressure to decrease carbon emissions. These findings offer policymakers valuable insights into developing a fair and efficient carbon allowance allocation strategy, while also contributing to China’s efforts to mitigate carbon emissions and combat climate change.

Mathematical Optimization of Carbon Storage and Transport Problem for Carbon Capture, Use, and Storage Chain

The greenhouse effect caused by carbon dioxide (CO2) emissions has forced the shipping industry to actively reduce the amount of CO2 emissions emitted directly into the atmosphere over the past few years. Carbon capture, utilization, and storage (CCUS) is one of the main technological methods for reducing the amount of CO2 emissions emitted directly into the atmosphere. CO2 transport, i.e., shipping CO2 to permanent or temporary storage sites, is a critical intermediate step in the CCUS chain. This study formulates a mixed-integer programming model for a carbon storage and transport problem in the CCUS chain to optimally determine ship allocation, ship departure scheduling, and CO2 storage and transport. Taking advantage of the structure of the problem, we transform the mixed-integer programming model into a simpler model that can be computed efficiently. To evaluate the performance of the simpler model, numerous computational experiments are conducted. The results show that all small-scale instances (each with 10 power plants) and medium-scale instances (each with 30 power plants) can be solved optimality by Gurobi within 14.33 s. For large-scale instances with 60 and 65 power plants, feasible solutions with average gap values of 0.06% and 6.93% can be obtained by Gurobi within one hour, which indicates that the proposed methodology can be efficiently applied to practical problems. In addition, important parameters, including the unit fuel price, the time-charter cost, and the ship sailing speed, are examined in sensitivity analyses to investigate the impacts of these factors on operations decisions. In summary, a lower fuel price, a lower charter cost, or a higher ship sailing speed can increase the profit of the CCUS chain.