CO2 Emission Control Research Articles

Review of Biofuel Effect on Emissions of Various Types of Marine Propulsion and Auxiliary Engines

The International Maritime Organization aims to reduce the maritime industry’s carbon emissions by 40% in the next two decades and has introduced measures to control CO2 emissions. These have significantly increased interest regarding biofuels, which can be used immediately on existing vessels, reducing their carbon footprint. The most common variant is B30, a blend of 70% crude oil and 30% biodiesel. Concerns exist for the potential effect on engine performance and NOx emissions. Scientific works on the subject are limited for two-stroke marine engines, while some studies are available for four-stroke ones, usually auxiliaries. To increase information availability on the subject, in this work, we review the results of testing on multiple marine engine types, two-stroke propulsion and four-stroke auxiliary units using B30 and conventional fuels. The effect on emissions and fuel efficiency is examined and cross-referenced with the available literature. A small increase in specific fuel consumption was observed for B30 use that varied with engine type. The increase was on average 1% for two-stroke and 2.5% for four-stroke engines. The effect of B30 on NOx emissions was low but varied between engines. For low-speed two-stroke engines, NOx increase was on average 4% compared to crude oil, and 2.4% for four-stroke auxiliary units, albeit with higher variance. For some four-stroke units, a decrease in emissions was found. All previous results were in line with other published studies. Overall, it was found that while biofuel effect can vary considerably between applications, 30% biodiesel blends can be used with no concerns regarding emissions and fuel efficiency.

Catalytic CO2 Desorption Study of Tri-Solvent MEA-EAE-DEEA with Five Solid Acid Catalysts

To achieve the CO2 emission control as the urgent task of Carbon Peak and Carbon Neutrality, the CO2 desorption experiments were performed with a new tri-solvent MEA-EAE(2-(ethylamino)ethanol)-DEEA(N, N-diethylethanolamine) with five solid acid catalysts: blended catalysts of γ-Al2O3/H-ZSM-5 = 2:1, H-Beta (Hβ), H-mordenite, HND-8, and HND-580 as H2SO4 replacement. A series of sets of experiments were performed in a typical recirculation process by means of both heating directly at 363 K and temperature programming method within 303~358 K to evaluate the key parameters: average desorption rate (ADR), heat duty (HD), and desorption factors (DF). After analyses, the 0.5 + 2 + 2 mol/L MEA-EAE-DEEA with catalyst HND-580 possessed the best CO2 desorption act at relatively low amine regeneration temperatures with minimized HD and the biggest DF among the other catalysts. Comparing with other tri-solvents + catalysts studied, the order of DF was MEA-BEA-DEEA + HND-8 > MEA-EAE-DEEA + HND-580 ≈ MEA-EAE-DEEA + HND-8 > MEA-EAE-AMP + HND-8. This combination has its own advantage of big cyclic capacity and wider operation region of CO2 loading range of lean and rich amine solution (αlean~αrich), which is applicable in an industrial amine scrubbing process of a pilot plant in carbon capture.

Enhanced CO2 mineralization and selective critical metal extraction from olivine and laterites

CO2 mineralization is a significant method for effective CO2 emission control because of formation of stable carbonate products and the availability of abundant mineral resources. The economic concern of the direct aqueous CO2 mineralization prevents the application to global warming mitigation. This work discovers that the CO2 mineralization of olivine can be significantly enhanced by using nitriloacetate (NTA) salt due to the competitive complexation and extraction of nickel and cobalt versus carbonate precipitation. The highly selective critical metal extraction can be also achieved and even considerably enhanced by using NTA compared to using ethylenediaminetetraacetate (EDTA) salt. Nearly 90% CO2 mineralization, nickel and cobalt extraction can be achieved and is suitable for both nickel-poor olivine and nickel-rich saprolite and limonite laterites. The recovery of nickel and cobalt makes the CO2 mineralization process favourable in both economics and technical outcome. The enhanced CO2 mineralization process can potentially earn $29, $557, and $221 net benefits for each t olivine, saprolite, and limonite, respectively. The success of the CO2 mineralization in technical and economic feasibility can potentially make the CO2 mineralization widely applicable and can make significant contributions to sustainable minerals engineering and resources management, and enhanced supply of critical metals and CO2 storage.

Integrated CO2 capture and utilisation: A promising step contributing to carbon neutrality

The release of CO2 into the atmosphere is problematic; however, it is an abundant, renewable, and inexpensive carbon resource. In the past, the environmental problems caused by excessive CO2 emissions, such as global warming and ocean acidification, have become increasingly severe. Carbon capture and utilisation (CCU) has drawn intensive interest due to its capacity to sequester CO2 and utilise it as a carbon source to produce high-value chemicals and fuels. However, state-of-the-art CCU exhibits poor economics and technological complexity due to extensive energy input, a multiple reactor configuration, and sorbent transfer between reactors for sorbent regeneration. Integrated CO2 capture and utilisation (ICCU) directly utilises CO2-containing exhaust gas and in situ upgrades them into valuable products in a highly intensified process, representing a more direct and promising path for CO2 emission control. A series of high-performance dual functional materials (DFMs) composed of catalytic and adsorbent sites have succeeded in various ICCU applications. In this account, we first briefly introduced the research background of ICCU technology and the motivation for developing various ICCU applications. Furthermore, we conducted a detailed description of ICCU technology from three aspects: ICCU-methanation, ICCU-dry reforming methane (DRM) and ICCU-reverse water gas shift reaction (RWGS). In particular, we have investigated the optimal adsorption and catalytic sites for specific reaction characteristics and have solved the problem of temperature matching between the adsorption and catalytic sites. In addition, The mechanism underlying ICCU technology has been explored, and the effect of interfering components on catalytic performance in real plant flue gases for future applications has also been analysed. Significantly, the catalyst stability was effectively improved by investigating the causes of catalyst deactivation. Finally, although the technology of in situ CO2 capture and conversion is still in its preliminary stages, we can see that current research results already indicate promising prospects. In-situ capture and conversion of CO2 into high-value-added chemical feedstock will be a very attractive application for reducing greenhouse gases in the atmosphere and recycling carbon resources. We are also committed to promoting the industrialisation and large-scale production of ICCU technology.

Industrial structure optimization under the rigid constraint of carbon peak in 2030: A perspective from industrial sectors

To explore how China can achieve sustainable economic development through industrial structure optimization of 28 sectors, this paper proposes a multi-objective economic-CO2 emission optimization model based on a rigid carbon peak constraint. Different development scenarios are set to reflect the tradeoff between economic development and CO2 emission control. The results reveal that (1) China can peak with 15,919.21 Mt. and 15,861.62 Mt. in 2030 under the emission control scenario and equilibrium development scenario, respectively. (2) The manufacturing sector (dominated by S11, S12 and S14), along with the electric power and heat production sector (S22) contribute most of the CO2 emissions in peak year. (3) After achieving the carbon peak, S11 has greater potential for economic growth and emission reduction; S12 and S14 will pay a higher cost to increase their emission reduction; while S22 can maintain stable output growth but has limited potential to reduce emissions. In addition, this study recommends that the construction of green manufacturing system and differentiated emission reduction policy system are necessary measures to reduce the carbon peak.

Social, economic, and technical factors affecting CO2 emissions in Iran.

Most scholars support the increase in carbon dioxide (CO2) emissions as one of the major causes of the increase in global climate change. Therefore, reducing CO2 emissions from the main emitter countries, including Iran as the sixth emitter, is important to deal with the harmful effects of global climate change. Accordingly, the main aim of this paper was to analyze the social, economic, and technical factors affecting CO2 emissions in Iran. Previous studies on diverse variables affecting emissions are not very accurate and reliable as they do not consider indirect effects. This study applied a structural equation model (SEM) to estimate the direct and indirect impacts of factors on the emissions by panel data for 28 provinces of Iran from 2003 to 2019. According to geographical location, three distinct regions, the north, center, and south of Iran were considered. The findings suggest that a 1% increase in social factor directly increased CO2 emissions by 2.23% (in the north) and 1.58% (in the center), but indirectly reduced emissions by 0.41% (in the north) and 0.92% (in the center). Hence, the total effects of the social factor on CO2 emissions were estimated at 1.82%, and 0.66% in the northern, and central regions, respectively. In addition, the total effects of the economic factor on CO2 emissions were estimated at 1.52%, and 0.73% in those regions. The results of this study showed that the direct effects of a technical factor on CO2 emissions were negative in the north and center. However, they were positive in the south of Iran. Based on the empirical results of this study, three policy implications are discussed in order to control CO2 emissions in regional distinctions of Iran as follows: First, policymakers should pay attention to the social factor, i.e., the growth of human capital in the southern region with the aim of increasing sustainable development. Second, Iranian policymakers must prevent unilaterally increasing gross domestic product (GDP) and financial development in the north and center. Third, policymakers should pay attention to the technical factor, i.e., improving energy efficiency, as well as upgrading information and communications technology (ICT) in the northern and central regions, and limiting the technical factor in the southern region.

The impact of global renewable energy demand on economic growth – evidence from GCC countries

PurposeThis study aims to examine the relationship between global renewable energy consumption and economic growth in Gulf Cooperation Council (GCC) countries from 2001 to 2019.Design/methodology/approachThis paper used a panel regression model to study the six GCC countries over the period from 2001 to 2019.FindingsAs expected, the findings indicated a significant and negative relationship between global renewable energy consumption and GCC economic growth. Additionally, there was a positive and significant relationship between GCC economic growth and the control variables, specifically labor, capital, CO2 emissions and non-renewable energy production.Practical implicationsThe results are of great importance to policymakers in GCC oil-exporting countries, as expected growth in renewable energy consumption will lower their economic growth in the future. Hence, they should first diversify their economy and lower their dependence on oil. Second, these countries can invest in solar energy through international joint ventures, especially with North African countries in close proximity to Europe, to become leaders in solar energy production.Originality/valueHow global energy consumption is related to GCC countries’ economic growth remains unclear, not only in GCC countries but also in many oil-exporting countries around the world, so future studies are needed. Furthermore, GCC governments will be able to create appropriate policies for the green economy and achieve their objectives if they have a comprehensive understanding of how global growth in renewable energy demand affects GCC economies.

Analysis of Interprovincial Differences in CO2 Emissions and Peak Prediction in the Yangtze River Delta

The Yangtze River Delta is the most populous and economically active region in China. Studying the reduction in CO2 emissions in this region is of great significance in achieving the goal of “peak carbon and carbon neutrality” in China. In this study, the Tapio decoupling and extended STIRPAT models were used to study the differences in provincial CO2 emissions characteristics and influencing factors in the Yangtze River Delta from 2001 to 2019. The results show that the growth rate of CO2 emissions was slower than that of economic development, which means that CO2 emissions and economic growth were in a state of weak decoupling. As found by ridge regression, the same factor has different impacts on CO2 emissions among provinces. The differences in these influencing factors were mainly caused by the imbalance of development in the Yangtze River Delta. Nine development scenarios were set out to predict the future trend of CO2 emissions based on economic development and carbon emissions technology using the extended STIRPAT model. It was found that low-carbon-emissions technology is conducive to controlling CO2 emissions in the Yangtze River Delta. In that case, the CO2 emissions would peak in 2029 at 1895.78~1908.25 Mt. Compared with the low-carbon-emissions scenarios, both the medium- and high-carbon-emissions scenarios are not conducive to achieving a carbon peak, with a 2~5-year delay in peak time and increasing emissions by 3.69~7.68%. In order to reduce the Yangtze River Delta’s CO2 emissions and pass the peak emissions as soon as possible, it is essential to not only optimize the energy structure, upgrade industries and promote the coordinated development of low-carbon technologies, but also promote emissions reduction in the transportation and construction fields and advocate for a low-carbon lifestyle among the public.

Predicting Carbon Dioxide Emissions with the Orange Application: An Empirical Analysis

The effects of climate change, such as droughts, storms, and extreme weather, are increasingly being felt around the world. Greenhouse gases are the primary contributors to climate change, with carbon dioxide (CO2) being the most significant. In fact, CO2 accounts for a significant percentage of all greenhouse gas emissions. As a result, reducing CO2 emissions has become a critical priority for mitigating the impacts of climate change and preserving our planet for future generations. Based on simulation and data mining technologies that use historical data, CO2 is expected to continue to rise. Around the world, 80% of CO2 emissions come from burning fossil fuels, mostly in the automotive or manufacturing industries. Governments have created policies to control CO2 emissions by focusing them on either consumers or manufacturers, in both developed and developing nations. Within the scope of this project, an investigation of vehicle emissions will be carried out using various attributes included within the vehicle dataset, as well as the use of many data mining techniques via the utilization of an orange application. The practical program is an example of organization, and the example will be about cars, exploring data, and figuring out how much gas will be needed. CO2 is taken away from cars, and we will use the CARS.csv file, which has data for a group of car types. It has a table with 36 records that shows the model, weight, and amount of carbon dioxide based on the car's size and weight.

Toward carbon neutrality in China: A national wide carbon flow tracing and the CO2 emission control strategies for CO2-intensive industries

Massive emission of CO2 as a potential driver of climate change has become a global issue presented in front of the whole human beings. Motivated by the CO2 cut-down requirement, China has aggressively undertaken restrictions aiming for peaking the carbon dioxide by 2030 and achieving carbon neutrality by 2060. However, due to the complex structures of industry and fossil fuel consumption in China, specific carbon neutrality route and the CO2 reduction potential are still open questions. To address the bottleneck of the “dual-carbon” target, quantitative carbon transfer and emission of different sectors are traced based on mass balance model. The future CO2 reduction potentials are predicted based on structural path decomposition, with consideration of energy efficiency enhancement and process innovation. Electricity generation, iron & steel industry and cement industry are identified as the top three CO2-intensive sectors, with CO2 intensity of at around 517 kg CO2/MWh, 2017 kg CO2/t CS and 843 kg CO2/t clinker, respectively. Non-fossil power is suggested to substitute coal-fired boilers to achieve decarbonization of the electricity generation industry, which is the largest energy conversion sector in China. As two dominant energy end-users, the iron & steel industry and cement industry exhibit different CO2 emission sources, requiring divergent approaches for low-carbon development. For the iron & steel industry, around 89 % direct CO2 emission comes from fossil fuel. Immediate energy efficiency enhancements are suggested, followed by process innovations such as oxy-blast furnaces, hydrogen-based reduction, and scrap-based electric arc furnaces. For the cement industry, around 66 % of direct CO2 emission comes from carbonate decomposition. The process innovation with CO2 enrich and recovery would be the most effectiveness for carbon reduction. Staged low-carbon policies of the three CO2-intensive industries are introduced at the end of this paper, which is capable of achieving 75–80 % cut down of CO2 emission intensity in China till 2060.

Transient simulation of heat and mass transfer in a parallel flow regenerative lime kiln with pulverized coal injection

Quicklime, which is an essential raw material in various industries, is primarily produced by thermally calcinating limestone in kilns. Among the various kiln designs, parallel flow regenerative (PFR) kilns with pulverized coal combustion are the predominant technology. The performance of the PFR kilns is determined by the interactions between the gas, limestone, quicklime, and coal particles inside the chamber. Additionally, the two chambers in the PFR kiln alternate after a short period during the operation. Consequently, the transfer behaviors between the various phases inside the chamber are in a transient state. A three-dimensional transient multiphase model was created to investigate the transient multiphase behavior. The entire operation cycle, which consists of calcination and regeneration processes, was simulated using a coupling method. The predicted CO2 concentration in the exhaust gas was compared with the industrial measurement data, and good agreement was obtained, with an error of less than 6%. Furthermore, variations in the gas and limestone temperatures and limestone concentrations with residence time during each period were obtained. During the calcination period, the gas temperature field stabilized after 100 s. After stabilization, the zone where intensive limestone decomposition occurred was located in the range 0–5 m from the lance tip. The maximum gas temperature in the calcination process was 1845 K, which was approximately 700 K higher than that of a PFR kiln fueled with natural gas. CO2 gradually accumulated in the middle part of the chamber; the average concentration of CO2 in the off-gas was 27.7%. In the regeneration period, the transfer process stabilization required 400 s. Furthermore, the maximum gas temperature was higher than that of a PFR kiln fueled with natural gas, with a difference of approximately 90 K. Contrary to the calcination period, CO2 accumulated in the peripheral region at the end of regeneration. The total CO2 emission is 1.2024 t CO2/t product for the investigated coal-fueled PFR kiln. These transient transfer characteristics, during the PFR operation, could aid the optimization of coal utilization and control of CO2 emissions in the future.

The Carbon Tax Effect on British Columbia Economy and Carbon Emission

A carbon tax is the most common carbon emission control policy widely used. British Columbia is the first Canadian province to use a carbon tax and implementing a carbon tax will impact British Columbia's environment and economy. This paper analyzes the scale of the carbon tax, energy consumption, GHG emission, and government revenue in British Columbia to evaluate the effect of the carbon tax. This paper finds that a carbon tax has no impact on dramatically reducing GHG British Columbia emissions, but it can help the government get more revenue. Although the carbon tax has little effect on reducing carbon emissions in British Columbia, the carbon emissions in British Columbia have been significantly reduced compared to other provinces. Therefore, we believe that the British Columbia carbon tax has a significant impact on controlling CO2 emissions, and the value of carbon emissions can be further controlled by increasing the carbon tax.

Evaluating the impacts of digitalization, financial efficiency, and education on renewable energy consumption: new evidence from China.

Policymakers around the globe have used various options for controlling CO2 emissions, among which increasing renewable energy consumption has proved to be the most viable. Consequently, this research attempts to look into the effects of financial efficiency, education, and digitization on renewable energy consumption in China from 1994 to 2020. To estimate the short- and long-run relationship between the variables, we have utilized the QARDL approach. The results suggest that the ICT, financial institutions and market development, education, GDP, and CO2 emissions all help improve renewable energy consumption in China in the long run. In the short run, the ICT, financial institutions and markets, education, GDP, and CO2 emissions all proved to be beneficial in increasing renewable energy consumption. In order to test whether our independent variables have a symmetric or asymmetric impact on renewable energy consumption, the Wald test is applied, which confirms the long-run nonlinear impact of ICT, financial institutions and markets, education, GDP, and CO2 emissions on renewable energy consumption, while the short-run asymmetric impacts are confirmed for a financial institution and GDP only. Therefore, governments should reinforce the amalgamation of digitalization, financial efficiency, and education while formulating policies for renewable energy consumption.

Investigating the role of the carbon tax and loss of power supply probability in sizing a hybrid energy system, economically and environmentally

Today, the use of renewable energy-based hybrid energy systems is widely welcomed due to their reduced environmental impact. Therefore, it is vital to optimally design these systems in terms of economy, reliability, and CO2 emissions. This work presents a new method based on Newton's Law of Gravity to achieve the above goals. For this purpose, the role of the carbon tax and the loss of power supply probability (LPSP) in sizing the hybrid energy systems is evaluated. Hence, distinct combinations of wind turbines, photovoltaic panels, and diesel generators are optimized by providing single and multi-purpose functions. Also, to produce cleaner energy, the carbon tax is enacted as a penalty function to control CO2 emissions. Furthermore, in this work, 45 cases are analyzed for achieving an optimal framework and some of the results obtained by the gravitational search algorithm (GSA) method are compared with the simulated annealing (SA) method. Therefore, according to the meteorological data, a PV/Wind/DG system with a total annual cost of 56,175 $/year and CO2 emission of 110,086 kg/year is suggested for the study area. In this case, by claiming a carbon tax of 0.05 $/kg, about 9 % of CO2 emission is prevented, and damage to human health is reduced by 8.9 %. Also, the outcomes display that more than 95 % of carbon dioxide emission is associated with using a diesel generator.

Spatio-temporal efficiency of fiscal environmental expenditure in reducing CO2 emissions in China's cities

Although market-based CO2 emission control measures (e.g., carbon tax and carbon trading market) have been deeply discussed, government-based measures have received limited attention. This has led to increased uncertainty regarding the formulation of targeted emission reduction policies. Using a unique dataset, the non-radial directional distance function, a proposed spatial meta-frontier analysis method, and the log t convergence model, this study comprehensively investigates the spatio-temporal trends in fiscal environmental expenditure efficiency (FE) and corresponding causes for in a case study for 106 Chinese cities over 2007–2019. The results show that city-level FE presented a slow upward trend at a relatively low level, with a clearly skewed distribution. The technology gap effect between city groups and the overall best production technology, and the efficiency gap effect within city groups were the main drivers widening the overall FE gap. Convergence analysis indicated that three convergence clubs of FE were found, which were distributed across the country. This study highlights that, when constructing fiscal environmental expenditure policies, the government should focus on balancing the regional gap of FE while comprehensively improving FE.

Potassium citrate-derived porous carbon with high CO2 capture and Congo red adsorption performance

The objective is to achieve the goal of carbon neutrality, controlling CO2 emissions is a primary problem to be solved in the current environmental protection field. Eliminating the environmental pollution of dyes in industrial wastewater is also an urgent problem to be solved in the field of environmental protection. The adsorption technique is an effective way to deal with these two issues. Developing high-efficiency adsorbents is an essential work in the adsorption field. In this work, a simple carbonization method has been developed to prepare porous carbon. The morphology and structure of the prepared porous carbon were investigated by scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and surface area measurement. By studying the influence of preparation conditions on the structure and properties of the prepared carbon materials, it was found that the carbon materials prepared at 900 ℃ (PCMCA-900) exhibited a high specific surface area of 1476 m2 g−1 and a high total pore volume of 0.951 cm3 g−1. The PCMCA-900 showed the highest CO2 uptake of 7.67 mmol g−1 at 0 ºC and the adsorption capacity of PCMCA-900 decreased by less than 5% after 10 times recycling. Moreover, when PCMCA-900 was used as an adsorbent to remove Congo red in water, an adsorption capacity of 652.3 mg g−1 was achieved. Therefore, potassium citrate-derived porous carbon is a desirable candidate for excellent CO2 adsorption and Congo red in industrial wastewater.

The impact of non-renewable energy production and energy usage on carbon emissions: Evidence from China

A high level of carbon dioxide (CO2) emission has become a global issue due to extensive production and energy usage that needs regulators’ attention and researchers’ emphasis. Hence, the study aims to explore the effectiveness of energy production and usage on carbon dioxide emission in China. The current study has taken the electricity production from oil, coal and nuclear as the measurement of energy production, while fossil fuel energy consumption and energy use have been taken as the measurement of energy usage, and energy import has been taken as the control variable. The secondary data has been gathered using a secondary source like World Bank from 1991 to 2020. The Quantile Autoregressive Distributed Lag (QARDL) was employed by the study to examine the linkage among variables, while the Augmented Dickey–Fuller (ADF) test was adopted to check the stationarity. The results revealed that electricity production from oil, coal and nuclear has a positive connection with CO2 emission. The findings also exposed that the FFEC, energy import, and energy use also have a positive linkage with CO2 emission. This study monitors the policymakers while establishing regulations to control CO2 emissions by limiting the country's energy production and usage.

Regulation and impact of VOC and CO2 emissions on low‐carbon energy systems resilient to climate change: A case study on an environmental issue in the oil and gas industry

AbstractThe impact of emissions from the fuel and energy sectors adversely affects the environment on the economies of countries. One of these pollutants is volatile organic compounds (VOCs), which contribute to the formation of tropospheric ozone. Emissions of hydrocarbon formation in the form of VOCs occur in four stages of the fuel and energy industry sector: (1) production, (2) processing, (3) transportation, and (4) storage. The oil and gas industry ranks among the top polluting industries in terms of VOC emissions. Research on the negative impact of VOCs, as well as CO2 emissions from the consequences of the extraction, processing, transport, and storage of oil and gas on the ecosystem of the planet and the population, has begun to be studied by science recently. Typically, these studies were conducted using laboratory and field analyses, as well as using data on anthropogenic emissions in the development of regulatory documents and requirements governing the control of VOC and CO2 emissions in the oil and gas industry. This paper presents a critical analysis of the literature on research on the negative effects of VOC emissions on the ecosystem and human health because of such factors as production, processing, transportation, and storage of hydrocarbons. This analysis shows the global magnitude of VOC emissions. Data from human‐made emissions from the oil and gas industry and direct emissions from transportation and energy processing were used to figure out how VOCs affect the environment around the world and how far they spread. In conclusion, this study found patterns of VOC emissions that show how important it is to control VOCs during the production, processing, transportation, and storage of oil and gas, as well as how important it is to create a single research base on emissions for each industry sector and on sources of greenhouse gas absorption.

Quantifying daily NOx and CO2 emissions from Wuhan using satellite observations from TROPOMI and OCO-2

Abstract. Quantification and control of NOx and CO2 emissions are essential across the world to limit adverse climate change and improve air quality. We present a new top-down method, an improved superposition column model to estimate day-to-day NOx and CO2 emissions from the large city of Wuhan, China, located in a polluted background. The latest released version 2.3.1 TROPOMI (TROPOspheric Monitoring Instrument) NO2 columns and version 10r of the Orbiting Carbon Observatory-2 (OCO-2)-observed CO2 mixing ratio are employed. We quantified daily NOx and CO2 emissions from Wuhan between September 2019 and October 2020 with an uncertainty of 31 % and 43 %, compared to 39 % and 49 % with the earlier v1.3 TROPOMI data, respectively. Our estimated NOx and CO2 emissions are verified against bottom-up inventories with minor deviations (<3 % for the 2019 mean, ranging from −20 % to 48 % on a daily basis). Based on the estimated CO2 emissions, we also predicted daily CO2 column mixing ratio enhancements, which match well with OCO-2 observations (<5 % bias, within ±0.3 ppm). We capture the day-to-day variation of NOx and CO2 emissions from Wuhan in 2019–2020, which does not reveal a substantial “weekend reduction” but does show a clear “holiday reduction” in the NOx and CO2 emissions. Our method also quantifies the abrupt decrease and slow NOx and CO2 emissions rebound due to the Wuhan lockdown in early 2020. This work demonstrates the improved superposition model to be a promising new tool for the quantification of city NOx and CO2 emissions, allowing policymakers to gain real-time information on spatial–temporal emission patterns and the effectiveness of carbon and nitrogen regulation in urban environments.

Spatiotemporal evolution of investment-carbon emission coupling coordination in China’s electricity market

Promoting the low-carbon development of the electricity market is the key to controlling CO2 emissions and achieving carbon neutrality in China. It requires the coordinated development between investment and carbon emissions in the electricity industry. Based on the panel data on electricity investment and carbon emissions from 2000 to 2019, this study systematically explains the coupling coordination mechanism between electricity investment and carbon emissions. We use the coupling coordination model to calculate the coupling coordination degree of each province. Then, the research uses the GM (1, 1) model to predict the coupling coordination development from 2020 to 2030. The study finds that the development of China’s electricity industry is in good shape. Although the coupling coordination degree has entered barely or primary coordination in most provinces, there are certain fluctuations in recent years; there are spatial differences in coupling and coordinated development among regions: the central region has a high coupling coordination degree, while the eastern and northeastern regions are relatively lagging behind. In the next 10 years, the coupling coordination degree will continue to grow, and all regions will reach the primary coordination. Among them, the central region will reach the intermediate coordination.