CO2 Emission Reduction Potential Research Articles

Progress in Corrosion Protection Research for Supercritical CO2 Transportation Pipelines

Carbon Capture, Utilization, and Storage (CCUS) technology is an emergent field with the potential for substantial CO2 emissions reduction, enabling low-carbon utilization of fossil fuels. It is widely regarded as a critical technology for combating global climate change and controlling greenhouse gas emissions. According to recent studies, China has identified CCUS as a key emissions reduction technology in climate change response and carbon neutrality objectives. Within this framework, supercritical CO2 (SC-CO2) transport pipelines are an essential means for efficient and safe transportation of CO2. Corrosion protection of pipelines enhances the efficiency and safety of CCUS technology and supports broader implementation and application. This paper reviews the current research on corrosion protection for SC-CO2 transport pipelines, discusses effect factors, compares various corrosion protection strategies, and analyzes the challenges in corrosion protection of SC-CO2 transport pipelines. It concludes with a perspective on future research and development directions in this field. This paper is dedicated to providing new research strategies for pipeline corrosion protection in CCUS technology in the future, and providing technical support for pipeline corrosion protection in CCUS industrial applications.

Techno-economic feasibility of CO2 utilization for production of green urea by Indian cement industries

The cement industry contributes substantially to global carbon emissions, necessitating urgent adoption of mitigation pathways aligned with climate goals. This study investigates the technical and economic viability of capturing carbon dioxide (CO2) emissions from cement plants in India and using that captured CO2 to produce green urea. The research aims to determine the feasibility of the CCUS approach as a practical way to reduce CO2 emissions from cement production while also boosting India's self-sufficiency in producing urea, a crucial fertilizer. The research uses a multi-criteria analysis (MCA) framework to assess various factors, including the technological readiness of CCUS technologies, the capital and operating costs of setting up and running such a system, the market demand for green urea, and the potential reduction in CO2 emissions. The study focused on 32 major cement plants in India, using data from their annual reports to inform the MCA model with an assumption of a post-combustion Monoethanolamine (MEA) scrubbing capacity CO2 capture capacity of 0.5 million tonnes per year per plant and used existing data and modeling techniques to analyze the feasibility of converting the captured CO2 into urea. The key findings indicate that this approach is promising and projects a 12.4% reduction in CO2 emissions from the cement industry if these 32 plants implement the CCUS technology. Additionally, it highlights a favorable market for the green urea produced, with an estimated output of 21.82 million tonnes per year, enough to offset a significant portion of India's reliance on urea imports. Financially, the study projects a six-year payback period and a 16.7% return on investment. It concludes that implementing CCUS technology to create green urea in Indian cement plants is technically and economically feasible. The approach has the potential to significantly reduce CO2 emissions while also supporting India's goal of self-sufficiency in urea production. However, further investigation and pilot-scale projects are recommended to validate the model's findings and optimize various aspects, such as managing flue gas impurities and leveraging waste heat for energy efficiency.

The potential of green ammonia in the de-fossilization of the steel, glass and cement industries.

The development of new technologies for the synthesis of green ammonia using exclusively hydrogen from water and nitrogen from air in processes driven exclusively by renewable energy is poised to decarbonize the production of this important molecule for the production of green fertilizers as well as offering a carbon-free vector for the long-term storage of renewable energy. In this article, we explore and quantify the CO2 emission reduction potential of green ammonia, evaluating how it can facilitate the decarbonization of other hard-to-abate industrial processes such as steel, glass and cement industries. Green ammonia can be used as a direct replacement of fossil fuels used as energy sources in the different processes. In addition, green ammonia can facilitate the electrification of the processes (so-called Power-to-X) by storing renewable energy in the long term to balance a decarbonized grid against intermittent renewable energy supplies. This article is part of the discussion meeting issue 'Green carbon for the chemical industry of the future'.

Research on the energy transition pathways of the transportation sector in the Guangdong–Hong Kong–Macao Greater Bay Area, China

Energy transitions is an effective way to achieve sustainable development in the transportation sector. To explore the pathways to energy transitions in the Guangdong–Hong Kong–Macao Greater Bay Area (GBA) transportation sector, the article evaluated the potential of energy savings and CO2 emission reduction of different measures in a quantitative way, based on the long-range energy alternatives planning (LEAP) platform. The marginal abatement cost curves are used to visually reflect the cost–benefit of these measures, and to develop cost-effective pathways to energy transitions. The results show that the measures of transportation modes adjustment and private cars regulating should be prioritized due to the potential of significant emission reduction with good cost-effectiveness. The measures of promoting electricity and hydrogen energy have large emission reduction potential, but only those for road traffic are cost-effective, and should be treated with a lower priority. Considering the high cost, the measures of promoting biofuel should be implemented as least priority. Moreover, the measures of liquefied natural gas (LNG) application have good cost-effectiveness, as opposed to limited CO2 emission reduction potential. It can only be used as a transitional fuel for the energy transitions. The findings and research methodology will provide theoretical support for the formulation of transportation energy transition pathways in the GBA and other regions.

Retrofit of a Marine Engine to Dual-Fuel Methane–Diesel: Experimental Analysis of Performance and Exhaust Emission with Continuous and Phased Methane Injection Systems

Shipping is a highly energy-intensive sector, and fleet decarbonization initiatives can significantly reduce greenhouse gas emissions. In the short-to-medium term, internal combustion engines will continue to be used for propulsion or as electricity generators onboard ships. Natural gas is an effective solution which can be used to mitigate greenhouse gas emissions from the marine sector. Considered to be a transitional fuel, it can provide a potential reduction in CO2 emissions of around 20–30%, compared with conventional marine fuels. This work investigated the influence of diesel-injection strategies on the performance and emissions of a single-cylinder prototype compression-ignition engine for marine applications, retrofitted to run as a Low-Pressure Dual-Fuel Engine using natural gas. Two different injection systems were used: a mass flow controller enabling continuous-mode gas feeding, and a Solenoid-Operated Gas Admission Valve for marine applications, the latter allowing phased natural-gas injection. Experimental tests were focused on partial-load conditions, which are critical for dual-fuel engines, with a natural gas/diesel mass ratio of 4:1. Phased injection resulted in reductions in fuel consumption, compared to continuous mode, of up to 11%. Further experiments demonstrated reductions in fuel consumption of up to 20.7% (in equivalent diesel); on the other hand, the unburned hydrocarbon emissions which resulted were an order of magnitude larger than the reference values for full diesel, reducing the benefits in terms of greenhouse gas emissions, with a reduction in Global Warming Potential of only 3% compared to full diesel.

A potential CO2 carrier to improve the utilization of HCO3– by plant-soil ecosystem for carbon sink enhancement

IntroductionImproving the rhizospheric HCO3– utilization of plant-soil ecosystem could increase the carbon sink effect of terrestrial ecosystem. However, to avoid its physiological stress on the crop growth, the dosage of HCO3– allowed to add into the rhizosphere soil was always low (i.e., <5–20 mol/m3). ObjectivesTo facilitate the utilization of relatively high concentrations of HCO3– by plants in the pursuit of achieving terrestrial carbon sink enhancement. MethodsIn this study, the feasibility of directly supplementing a high concentration HCO3– carried by the biogas slurry to the plant rhizosphere was investigated using the tomato as a model plant. ResultsThe CO2-rich biogas slurry was verified as a potential CO2 carrier to increase the rhizospheric HCO3– concentration to 36 mol/m3 without causing a physiological stress. About 88.3 % of HCO3– carried by biogas slurry was successfully fixed by tomato-soil ecosystem, in which 43.8 % of HCO3– was assimilated by tomato roots for the metabolism, 0.5 ‰ of HCO3– was used by microorganisms for substances synthesis of cell structure through dark fixation, and 44.4 % of HCO3– was retained in the soil. The rest of HCO3– (∼11.7 %) might escape into the atmosphere through the reaction with H+. Correspondingly, the carbon fixation of tomato-soil ecosystem increased by 150.1 g-CO2/m2-soil during a tomato growth cycle. As for the global countries that would adopt the strategy proposed in this study to cultivate the tomato, an extra carbon sink of soil with about 1031.1 kt-C per year (i.e., an additional 0.21 tons of carbon per hectare soil) could be obtained. ConclusionThis would be consistent with the goal of soil carbon sink enhancement launched at COP21. Furthermore, the regions with low GDP per capita may easily achieve a high reduction potential of CO2 emissions from the agricultural land after adopting the irrigation of CO2-rich biogas slurry.

Life cycle assessment of roll-to-roll produced chemical vapor deposition graphene transparent electrodes towards copper foil recycling

Graphene transparent electrode (GTE) has been attracting much attention due to fascinating physical properties. However, the extensive deployment of copper foil within GTE production has imparted substantial environmental burden. This paper is a cradle-to-gate life cycle assessment (LCA) study to investigate the environmental impacts of roll-to-roll produced chemical vapor deposition (CVD) GTE and the environmental potential of recycling copper foil for cleaner production. Four production scenarios are developed to promote the lab-to-fab progress, including lab scenario, industry baseline scenario, industry recycling scenario and microwave plasma chemical CVD scenario. The functional unit is set as 1 m2 of the GTE production and the life cycle inventories of different scenarios are explored. Results show that the copper foil is a major contributor in baseline scenario in the category of primary energy consumption and global warming. The impacts of GTE production in industry recycling scenario vary from 0.01 to 0.18 of the values in industry baseline scenario. Therefore, copper foil recycling shows environmental potential for GTE production. If all building integrated photovoltaics transition to employing perovskite solar cells with GTE produced in copper recycling scenario, the potential reduction in CO2 emissions is estimated at 141.2 million kilograms per year. The findings serve as a roadmap for the industry, highlighting key areas where improvements can be made to upscale production while minimizing environmental impact. This paper provides insights into the major environmental contributors in the GTE production, guiding the upscaling routes for cleaner GTE production in the future.

Modelling of carbon flows in the value chain of packaging plastics in the context of sustainable carbon management

The low share of plastic recycling means significant losses for the economy as well as for the environment, especially for plastic packaging materials since they are the largest end-use market for plastics and characterized by a typical short first-use cycle. The main polymers used in packaging applications are basic polymers, such as PE, PP, PS and PET, which consist mainly of fossil carbon locked up in polymer form. This study attempts to map carbon flows across the packaging plastics value chain with the goal to optimize carbon fixation in relevant polymers over multiple life cycles and minimize carbon loss to the atmosphere via CO2 emissions. Evaluating these carbon balances in the production, consumption and end-of-life treatment phase of these polymers provides more insight in the carbon losses during their life cycle. Three case studies were considered; (1) a baseline route (BASE), representing the current linear plastics economy model which is benchmarked with two theoretical sustainable scenarios: (2) an electrified (ELEC) and (3) a biobased (BIO) route. Specific parameters and assumptions in these three cases were adapted, such as feedstock type, recycling rate, type of recycling etc. Improved recycling rates and advanced recycling methods were applied in the sustainable cases and had a positive effect on carbon retention in products. Allowing a numerical comparison, a method was developed to quantify this carbon retention via the half lifetime of carbon in materials over multiple life cycles. The half lifetime evolved from 0.3 year in the BASE route to 2.0 and 2.6 years in the BIO and ELEC route, respectively. However, even these sustainable, optimized routes remained insufficient to embed carbon in plastic products for many years without too much carbon loss. It is inevitable that an enhanced (carbon) circularity in these routes comes by a certain energy cost; about 46 GJ more energy was required per extra recycled ton carbon in the ELEC route (compared to BASE). But at the same time this intensified carbon conservation leads to a CO2 emission reduction potential of 80 %. The present work illustrates the potential of chemical recycling, and carbon capture and utilization (CCU) techniques for end-of-life treatment of plastic packaging products, but additional process development and process intensification in all facets of the value chain are needed to minimize carbon leakage over multiple lifecycles. Hence, waste management policy could be an important instrument to support further enhancement in plastics circularity.

WITHDRAWN: Optimizing smart building energy systems for sustainable living: A realistic approach to enhance renewable energy consumfaption and reduce emissions in residential buildings

The presented a groundbreaking and economical approach to enhancing the sustainability of residential buildings by optimizing smart building energy systems. This approach, which is instrumental in advancing the shift towards a sustainable future, focuses on maximizing occupant comfort while markedly diminishing the energy footprint and emissions of the built environment. The study offers a comprehensive techno-economic and environmental analysis of the system performance conducted on residential apartments in Baghdad, Iraq. The results are promising, showing that the system successfully transfers 75.6 MWh of renewable electricity to the local grid and utilizes an additional 120.42 MWh for the internal needs of the building and operation of electrical components. A key component of the system is the biomass heater, which meets over 70.2% of the heating demand, proving particularly effective during periods of low solar power availability and high electricity costs. This highlights the importance of integrating diverse energy sources to reduce dependence on the grid. The results also reveals that the costs associated with energy consumption are substantially offset by the revenue generated from selling excess renewable energy during high-production periods. This results in average monthly energy costs being maintained below $151.2/MWh over several years. This cost-efficiency is achieved by eschewing batteries and optimizing the dimensions of the heat pump. Additionally, the system demonstrates a low emission index of 12.85 kgCO2/MWh, indicating a potential reduction in CO2 emissions by 75.6 TCO2/year compared to traditional energy mixes.

The integration of solar-hydrogen hybrid renewable energy systems in oil and gas industries for energy efficiency: Optimal sizing using Fick's Law optimisation Algorithm

The global demand for sustainable energy solutions in the oil and gas industry has stimulated interest in the integration of renewable energy sources. This paper investigates the techno-economic and environmental aspects of incorporating a solar-hydrogen-based hybrid renewable energy system (SHRES) into oil and gas processing facilities.The proposed SHRES, comprising Solar PV modules, hydrogen production and storage systems, and a gas turbine generator (PV-FC-EL-Tank-GT), aims to enhance energy efficiency and reduce the carbon footprint of energy-intensive operations. The study utilises a multidisciplinary approach, encompassing engineering, economics, and environmental analysis. The techno-economic evaluation employs detailed modelling and optimisation using Fick's Law Algorithm, ensuring efficient energy production and cost-effectiveness. Ecological assessments quantify potential reductions in greenhouse gas emissions and other environmental impacts.The technical and economic evaluation identifies the electrolyser system as the most significant cost contributor (57%). The optimised system balances energy sources with 45% from PV modules, 35% from fuel cells, and 20% from gas turbines, showcasing substantial reliance on renewable energy while maintaining required power generation.Addressing the urgent need for sustainable energy solutions in the oil and gas industry, the study highlights the potential of SHRES integration. By employing Fick's Law Algorithm, alongside with 80 % of renewable energy integration, the research optimises system components to optimise the annualised cost to be $57,539.85, decrease to zero the Loss of Power Supply Probability (LPSP), and mitigate CO2 emissions to a lowest value of 0.147 gCO2eq/kWh (by 80 %). The electrolyser system's pivotal role and the distribution of power generation sources are emphasised.This study presents a novel approach to integrating solar-hydrogen systems into oil and gas processing facilities, aiming for sustainability. The findings underscore the significance of the electrolyser system and the distribution of power generation sources in optimising the SHRES. Recommendations for renewable energy integration and potential reductions in CO2 emissions and costs are discussed, providing valuable insights for future energy policies.

Hydrogen in aviation: A simulation of demand, price dynamics, and CO2 emission reduction potentials

Aviation contributes to anthropogenic climate change by emitting both carbon dioxide (CO2) and non-CO2 emissions through the combustion of fossil fuels. One approach to reduce the climate impact of aviation is the use of hydrogen as an alternative fuel. Two distinct technological options are presently under consideration for the implementation of hydrogen in aviation: hydrogen fuel cell architectures and the direct combustion of hydrogen. In this study, a hydrogen demand model is developed that considers anticipated advancements in liquid hydrogen aircraft technologies, forecasted aviation demand, and aircraft startup and retirement cycles. The analysis indicates that global demand for liquid hydrogen in aviation could potentially reach 17 million tons by 2050, leading to a 9% reduction in CO2 emissions from global aviation. Thus, the total potential of hydrogen in aviation extends beyond this, considering that the total market share of hydrogen aircraft on suitable routes in the model is projected to be only 27% in 2050 due to aircraft retirement cycles. Additionally, it is shown, that achieving the potential demand for hydrogen in aviation depends on specific market prices. With anticipated declines in current production costs, hydrogen fuel costs would need to reach about 70 EUR/MWh by 2050 to fulfill full demand in aviation, assuming biofuels provide the cheapest option for decarbonization alongside hydrogen. If e-fuels are the sole option for decarbonization alongside hydrogen, which is the more probable scenario, the entire hydrogen demand potential in aviation would be satisfied according to this study's estimates at significantly higher hydrogen prices, approximately 180 EUR/MWh.

Promote the decarbonization pathways of eco-industrial parks by considering their CO2 emissions structures and characters

China has proposed the goals of a carbon peaking target in 2030 and a carbon neutrality target in 2060 to mitigate climate change. In China, Eco-industrial parks (EIPs) are one of the platforms for achieving energy conservation and emission reduction. This study aims to investigate the future CO2 emissions reduction potential by evaluating two different types of national EIPs in China. Firstly, we constructed carbon emission inventories for EIP-N in Zhejiang Province and EIP-L in Shandong Province. Subsequently, leveraging these inventories, we developed an integrated model aimed at predicting the carbon emission peaks for both EIPs and discerning the main contributors. Secondly, we took EIP-N and EIP-L as examples and applied the Long-range Energy Alternatives Planning (LEAP) model to establish three different scenarios for analyzing the future trends in carbon emissions. In a Business as usual (BAU) scenario (continue the current energy conservation and emission reduction policies), EIP-L can achieve carbon peaking, while the carbon emissions of EIP-N will continue to increase. In the Emissions control (EMC) scenario (considering the reduction of fossil fuels and the increased use of cleaner energy sources), EIP-N and EIP-L are projected to peak in 2029 and 2027, respectively. In the Reinforce mitigation (RFM) scenario (with fewer emissions from fuels and a higher share of clean energy generation), both EIPs are expected to achieve carbon peaking by 2025. Finally, we proposed the deep decarbonization of EIPs with different industrial characteristics. This study applied the LEAP model to the EIP scale, explored the paths of deep decarbonization development in different EIPs under the constraint of dual-carbon targets, providing a demonstration for China and other developing countries to achieve the goal of carbon capping in EIPs during rapid industrialization.

Research on the coal saving and emission reduction potential of advanced technologies in China's iron and steel industry

The coal-based energy consumption structure has led to high coal consumption and carbon emissions in China's iron and steel industry, and the task of coal saving and carbon reduction in the steel industry is difficult and urgent. The economic viability of various coal-saving and emission-reduction technologies, the extent of their coal-saving and emission-reduction potential, and the guidance on the adoption of advanced technologies are crucial issues that need to be addressed in the Chinese steel industry. This article employs the Energy-Production (E-P) analysis method and the Conservation Supply Curve (CSC) model incorporating coal consumption ratio coefficients to systematically analyze coal consumption and carbon dioxide emissions in the overall iron and steel industry and its sub-processes under different scenarios. It calculates the coal-saving emission reduction costs of 32 technologies, evaluates them comprehensively based on their coal-saving and emission-reduction potentials and cost-effectiveness, and categorizes them accordingly. According to the cost of coal saving and emission reduction as the demarcation point, a total of 19 technologies are cost-effective; according to the coal-saving emission reduction potential and cost division, 32 technologies are divided into 6 categories, among which 6 technologies such as sintering waste heat recovery technology can be used as key technologies for popularization and application. Seven technologies, such as efficient preheating technology of ladle, have high cost and low potential, which can be gradually eliminated or improved and upgraded. After the comprehensive promotion of the 32 technologies, the maximum coal saving potential is about 3.453 billion GJ, the CO2 emission reduction potential is 395 million tons, the total coal consumption of the steel industry can be reduced to about 13.904 billion GJ, and the carbon dioxide emissions can be reduced to 1.179 billion tons.

Policies and energy consumption-driven trends facilitating development of the value chain for wind energy component manufacturing in Lithuania

&#x0D; &#x0D; &#x0D; The paper is aimed at analysing policies and energy consumption related trends motivating the development of the value chain for wind energy component (WEC) manufacturing in Lithuania. A comparative literature review and statistical data (2000–2022) analysis were employed for the purpose. The policy overview revealed that investment, climate and energy policy, and related measures establish the preconditions for the entry of manufacturing enterprises into the value chain for WEC as they are creating the demand for domestic and foreign WEC. The results of statistical data analysis showed that from 2009 through 2019, the annual rate of primary energy consumption (PEC) decreased by an average of 0.5% per year, and in 2020 as much as 8.5% due to the COVID-19 lockdown in the European Union (EU). Though the EU countries are still dominated by fossil fuels and related carbon dioxide (CO2) emissions are high (2.8 Gt in 2022), over the last decade, the use of renewable energy sources (RES) was growing rapidly, with a tenfold increase in solar energy and a threefold increase in wind energy consumption. As a clean energy technology, wind power plants (PPs) have the highest CO2 emission reduction potential per MW; also, wind energy is among the cheapest sources of electricity production. Since the EU is a worldwide leader in installations of wind energy capacity and technology deployment, it provides a solid basis for further development. Currently, most of the off-shore plants are operating in the North Sea, but with the new wind parks in the Baltic, Black and Mediterranean seas as well as in the Atlantic Ocean, wind energy could meet more than 80% of electricity demand in Europe. The implementation of wind energy projects requires development of WEC manufacturing activities in EU countries.&#x0D; &#x0D; &#x0D;

Development of a framework to forecast the urban residential building CO2 emission trend and reduction potential to 2060: A case study of Jiangxi province, China

Investigating the CO2 abatement potential of urban residential building from systematic perspective is essential to reach the urban carbon neutrality target. However, previous studies on building CO2 emission trend forecasting were mainly focused on the building operational phase. In this study, a new framework that includes four building stages under a system dynamic model is developed to simulate urban residential building carbon emission changes and the related reduction potentials under three scenarios in Jiangxi Province up to 2060. Results showed that the overall process carbon emission dynamic had already peaked in 2014 under the three scenarios, with a peak value of 38.52 Mt. It then fell to 9.56 Mt in 2060 under the baseline (BAU) scenario. More importantly, seven carbon abatement measures were adopted during four building activities in this study, and the total carbon reduction was not the sum of the carbon reduction potential of the individual measures. Some carbon abatement strategies displayed synergistic effects such as low-carbon electrification where the combination of electrification and clean energy power generation was the largest contributor to reduced carbon emissions during building operation as a comprehensive carbon reduction measure. By contrast, extending a building's lifetime restrained the carbon abatement potential during the demolition stage, and it inhibited the carbon emission reduction by 24.84 Mt. These results highlight the significant need for effective policy interventions for clean production and the need to improve prefabricated building proportions, promote electrification, improve energy efficiency, strengthen recycling practices, and extend building lifetimes to promote decarbonization of urban residential building system development.

Decarbonization potential collaborated with source industries for China's iron and steel industry towards carbon neutrality

Towards the target of carbon neutrality, the need for deep decarbonization in iron and steel industry is increasingly recognized. Existing studies rarely mention the effects of collaboration with its source industries for carbon emission reduction in ISI. Furthermore, the fundamental laws of CO2 emission reduction capacity with cost change of source substitutions for various steel production routes under market economics are unclear. To avoid the blind substitution of clean sources for meeting the urgent requirements for decarbonization in China's steel industry, which may result in increased carbon emissions and uneconomical carbon reduction from a lifecycle perspective. This paper integrates the production and utilization processes of source resources into the steel production process, establishes coupling models of carbon and value flows for four main types of steel production routes, and aims to quantitatively analyze the specific CO2 emission reduction potential and costs. Three economic market development scenarios from 2021 to 2060 are set, and the marginal carbon prices of various source substitutions are determined. Subsequently, decarbonization pathways with the goal of minimizing production costs are developed. Finally. The future resource demand and the carbon emission reduction contributions of source industries collaborated are predicted. The results show that (1) about 81.7–89.9 % of CO2 emissions could be reduced in the scenarios; (2) the demands of electric power and hydrogen energy will reach 54.48–511.90 BkWh and 7.47–10.31 Gt in 2060, respectively; and (3) collaboration with source industries could make 18.3–18.3% of CO2 emission reduction contributions. All in all, this study could provide scientific support for the low-carbon transformation of China's steel industry.

The potential of CO2 emission reduction via replacing cement with recyclable wastes in the construction industry sector: the perspective of Iran’s international commitments

The potential of CO2 emission reduction via replacing cement with recyclable wastes in the construction industry sector: the perspective of Iran’s international commitments

Spatiotemporal analysis of CO2 emissions and emission reduction potential of Beijing buses using smart card data

Human activities, primarily carbon dioxide emissions, have undeniably caused global warming. The transportation sector contributes about a quarter of global CO2 emissions. While replacing traditional buses with electric ones has reduced emissions, it is crucial to consider the indirect emissions resulting from electricity consumption. This study proposes a framework for modeling bus emissions using smart card data, integrating spatiotemporal distribution characteristics and emission reduction potentials. Our analysis reveals that routes spanning 10–30 km contribute to 81% of total bus emissions, with an average emission rate of 56.2 gCO2/per-km for residents traveling by bus. Bus emissions also exhibit cyclical variations during holidays, weekdays, and weekends, indicating spatial clustering and trends. Although the area within Beijing's 4th Ring Road constitutes only 13% of the total area within the 6th Ring Road, it generates almost half of the CO2 emissions. With urban expansion, total bus emissions increase gradually, but emission intensity decreases. This study emphasizes the potential for reducing emissions through improved public transportation operations. It recommends fully electrifying the bus fleet and employing low grid emission factors, which could reduce emissions by up to 71% compared to diesel options. Electrification of buses and optimizing power generation on the grid are essential priorities for emission reduction.

Computation of the environmental performance of ready-mix concrete for reducing CO2 emissions: A case study in Egypt

Concrete is one of the largest sources of carbon dioxide (CO2) worldwide due to the use of cement as its main component. The share of CO2 from cement industry is about 7%. There is a growing need for ways and methods to systematically identify, asses, modify, the cement production process for emission reduction. In line with Egypt commitment to climate change in the COP27, a framework is designed for the assessment of the cement plant. The aim of this paper is to investigate and calculate the CO2 emissions from a building in the New Egyptian Administrative Capital in the area of R5 using ready mix concrete. This study used compiled data of emission factors from Titan Egypt cement plant as the producer of cement in R5. The essential data needed for the calculations were collected from the literature with the guidance of the Intergovernmental Panel of Experts on Climate Change (IPCC) Guidelines for National Greenhouse Gas Inventories, the Cement Sustainability Initiative (CSI) of the World Business Council for Sustainable Development (WBCSD) as well as the inventory sustainability reports guided by the Egyptian Environmental Affairs Agency (EEAA). This is done on two parts: the calculation of CO2 total emissions of the baseline scenario and the second part is a computation of the emissions based on the alternative use of different categories such as raw materials, fuel consumption, energy efficiency, transportation, and water consumption. A comparison between the baseline and the alternative case took place to compute the percentage of reduction in emissions from concrete. The study findings are promising. The total amount of emissions from the concrete used in this project is about 3114.49 tons. By using the mitigation measures, there is a potential reduction in the total CO2 emissions of the building by calculations is concluded to be around 5.94%.

Prediction of CO2 emission peak and reduction potential of Beijing-Tianjin-Hebei urban agglomeration

Forecasting the future emission trajectories and the relating sensitive driving factors of emissions for cities is of great significance to formulate realizable CO2 mitigation policies. To proceed the forecasting, studies on peak prediction and quantification of reduction potential at the city level are essential. However, the studies in the area are very limited. Selecting the Beijing-Tianjin-Hebei urban agglomeration (BTH) as the study region, this paper aims to contribute to the research area and provides implications for other cities or urban agglomerations. The Kaya identity and multi-scenario simulation were employed to predict the dynamic evolution pathways of CO2 emissions from 2021 to 2035 and explore the differential CO2 peak time, peak value, and reduction potential for 13 cities in BTH. Monte Carlo simulation, Mann-Kendall trend test and Sen's slope estimation method are jointly used to reduce uncertainties in estimation. The Monte Carlo simulation results show that most cities in BTH have already reached their CO2 emissions peak, while Tianjin, Langfang, Cangzhou and Tangshan are expected to reach their peaks between 2025 and 2030. Among them, 5 and 8 cities have the risk of not reaching their peak before 2035 in the high consumption scenario (HCS) and extensive development scenario (EDS) respectively. Comparative analysis reveals that low-carbon scenario (LCS) and sustainable development scenario (SDS) have significant effects on emissions reductions. The top three cities in terms of accumulative emission reduction in 2021–2035 are Tianjin, Tangshan and Cangzhou, estimated as 117.82–250.75 Mt CO2 in LCS and 217.77–454.10 Mt CO2 in SDS, respectively. The results of sensitivity analysis reveal that the most critical driver of CO2 emissions in Beijing is population, while that is GDP per capita for Tianjin. Langfang and Hengshui showed the highest sensitivity to energy intensity. Accordingly, these cities have differentiated concerns and priorities to achieve their carbon peak goal as scheduled.