Emission Abatement Research Articles

Oxidation capacity changes in the atmosphere of large urban areas in Europe: Modelling and experimental campaigns in atmospheric simulation chambers

Air pollution is a major concern for human health and the environment. Consequently, environmental standards have become stricter to improve air quality. Thanks to this, the ambient levels of O3 precursors such as VOCs and NOX have decreased. However, O3 levels in Europe, especially during winter, have increased, potentially impacting on atmospheric oxidation capacity and the associated chemistry of tropospheric oxidants. In this work, we focus on recent changes in the oxidation capacity of urban atmospheres. The study is conducted with the results of the CMAQ modelling system with a regional resolution with 12 × 12 km2 across the entire European continent for the winter (January) and summer (July) of 2007 and 2015. The 2015 meteorological data is used for both years to emphasise emission changes during the studied period. We scrutinise the changes in ambient concentration levels of the main tropospheric oxidants (O3 and HOX radicals) in five representative cities, Valencia, Madrid, Milan, Berlin, and The Hague. The enhanced O3 formation in winter seems to be due to the low VOC/NOX ratio, while the opposite trend in summer may be related to a relatively high ratio. Additionally, photooxidation experiments are carried out in the EUPHORE chambers to study the effect of changes in NOX concentration and NO/NO2 ratio on the variation of the given oxidants at constant VOCs concentrations. For the baseline experiments, two scenarios are selected based on the model results of 2015: two representative winter and summer days of low and high pollution in Berlin and Madrid, respectively. The role of VOC/NOX and NO/NO2 ratios on atmospheric reactivity is discussed. As a result, it is first suggested that further decreases in ambient NOX levels are required to reduce ambient O3 levels. Moreover, additional factors should be considered when designing local-specific emission abatement strategies.

Climate uncertainty impacts on optimal mitigation pathways and social cost of carbon

Emissions pathways used in climate policy analysis are often derived from integrated assessment models. However, such emissions pathways do not typically include climate feedbacks on socioeconomic systems and by extension do not consider climate uncertainty in their construction. We use a well-known cost-benefit integrated assessment model, the Dynamic Integrated Climate-Economy (DICE) model, with its climate component replaced by the Finite-amplitude Impulse Response (FaIR) model (v2.1). The climate uncertainty in FaIR is sampled with an ensemble that is consistent with historically observed climate and Intergovernmental Panel on Climate Change (IPCC) assessed ranges of key climate variables such as equilibrium climate sensitivity (ECS). By varying discounting assumptions, three scenarios are produced: a pathway similar to the ‘optimal welfare’ scenario of DICE that has similar warming outcomes to current policies, and pathways that limit warming to ‘well-below’ 2 and 1.5 with a short-term overshoot, aiming to meet Paris Agreement long-term temperature goals. Climate uncertainty alone is responsible for a factor of five variation (5%–95% range) in the social cost of carbon (SCC) in the 1.5 overshoot scenario, with the spread in SCC increasing in relative terms with increasing stringency of climate target. CO2 emissions trajectories resulting from the optimal level of emissions abatement in all pathways are also sensitive to climate uncertainty, with 2050 emissions ranging from −12 to +14 GtCO2 yr−1 in the 1.5 scenario. ECS and the strength of present-day aerosol effective radiative forcing are strong determinants of SCC and mid-century CO2 emissions. This shows that narrowing climate uncertainty leads to more refined estimates for the social cost of carbon and provides more certainty about the optimal rate of emissions abatement. Including climate and climate uncertainty in integrated assessment model derived emissions scenarios would address a key missing feedback in scenario construction.

Machine learning approaches reveal highly heterogeneous air quality co-benefits of the energy transition

Estimating health benefits of reducing fossil fuel use from improved air quality provides important rationales for carbon emissions abatement. Simulating pollution concentration is a crucial step of the estimation, but traditional approaches often rely on complicated chemical transport models that require extensive expertise and computational resources. In this study, we develop a machine learning framework that is able to provide precise and robust annual average fine particle (PM2.5) concentration estimations directly from a high-resolution fossil energy use dataset. Applications of the framework with Chinese data reveal highly heterogeneous health benefits of avoiding premature mortality by reducing fossil fuel use in different sectors and regions in China with a mean of $19/tCO2 and a standard deviation of $38/tCO2. Reducing rural and residential coal use offers the highest co-benefits with a mean of $151/tCO2. Our findings prompt careful policy designs to maximize cost-effectiveness in the transition toward a carbon-neutral energy system.

Investigating the asymmetric impact of renewable energy consumption and trade openness for carbon emission abatement using N-ARDL approach: a case of India

PurposeThis study investigates the asymmetric influence of renewable energy consumption (REC) and trade openness (TO) in the pathway of decarbonizing of Indian economy.Design/methodology/approachBy exploiting fifty years of annual time series data spanning from 1970 to 2019 with the augmentation of nonlinear autoregressive distributed lag technique with the consideration of GDP and industry value added (IVA) as control variables.FindingsOur This research not only demonstrates the asymmetric association among the employed variables but also shows that negative shock to REC stimulates emissions, where as positive shock on the same policy variable promotes environmental quality improvement. Negative shock to TO is found to be associated with the corresponding increase of environmental quality, but the positive shock on the same intensifies environmental pollution. IVA is also found to be associated with intensifying environmental squalor. In addition, the research provides the empirical evidence of existence of “EKC” hypothesis in India as long-run coefficient associated with GDP looks smaller than short-run coefficient of GDP.Research limitations/implicationsIt was difficult to include may other causal variables due to nonavailability of data pertaining to those variables.Practical implicationsMoreover, some policy guidelines have also been recommended for India at the end that may aid India to achieve net zero emissions by 2070.Originality/valueThis is an original research paper carried out by the authors and has not yet been submitted elsewhere.

Resource efficiency and climate change policies to support West Asia's move towards sustainability: A computable general equilibrium analysis of material flows

The resources and energy sectors make a significant contribution to economic performance in the economies of West Asia. In this study we explore the effect ambitious policies for resource efficiency and greenhouse gas abatement would have on West Asian economies and what their contribution to environmental sustainability could look like. We employ the Global Trade and Environmental Resource Model (GTEM-Resource) to empirically assess the economic and environmental implications of global policy initiatives in the region. Results show that resource efficiency and greenhouse gas (GHG) abatement policies are complementary in their effects. Resource efficiency policies boost resource use productivity in the region, reduce all categories of material extraction based on sustainable consumption and production behaviour and also caused by trade, and foster economic performance. By contrast, GHG emission abatement policies have a small effect on resource productivity but drive significant GHG reductions that are accompanied by reduced economic performance. When these two policies are combined, real GDP in West Asia is projected to increase by 8% relative to business-as-usual by 2060, while resource extraction and GHG emissions levels in the region would decline dramatically by 40% and 50%, respectively. Saudi Arabia and the United Arab Emirates would be much better off, compared to other countries in the region, with large increases in real GDP and major reductions in GHG emissions and resource extraction levels. Findings suggest that technology development and climate mitigation policies would result in a win-win solution for all countries in West Asia, contributing to maintaining well-being and protecting the environment on regional and global scales. This shows that there is a pathway to economic prosperity for resource-rich countries and regions.

Numerical Optimization Study of the Resistance Coefficient of U-Shaped Air Distributor

In this paper, the optimization of the flow channel structure of the U-shaped air distributor is proposed. Fluent meshing was used to mesh the multipatch meshing of the original model of the grid air distributor, and then the CFD numerical simulation was carried out by using Fluent 2022R1 to obtain the internal air flow state of the air distributor flow channel. Through the orthogonal experimental design and a comprehensive analysis method, the optimal size structure for resistance performance is obtained as S = 60 mm, RL = 125 mm, L = 160 mm, D = 100 mm, the resistance coefficient of the new structure as 1.375, and the pressure loss as 56.87 Pa, by using 3D modeling software (SOLIDWORKS 2015) and Fluent. Compared with the initial scheme, the resistance coefficient and pressure loss are reduced by 3.03% and 6.29%, respectively. To summarize, the research in this paper offers a substantial contribution to the realm of energy conservation and emission abatement in ship air conditioning systems, simultaneously furnishing invaluable guidance for the design of air distributors.

Influences of large-scale farming on carbon emissions from cropping: Evidence from China

Reducing agricultural carbon emissions is important to enable carbon emission peaking by 2030 in China. However, China's transformation towards large-scale farming brings uncertainties to carbon emission reduction. This study quantifies the carbon emissions from cropping based on life cycle assessment and estimates the effects of farm size on carbon emissions using a fixed effects model. Furthermore, the variations of the carbon emissions from cropping driven by the changes in farm size in future years are projected through scenario analysis. Results demonstrate an inverted U-shaped change in total carbon emission from cropping as farm size increases, which is dominated by the changes in the carbon emission from fertilizer. Projections illustrate that large-scale farming transformation will postpone the peak year of total carbon emission from cropping until 2048 if the change in farm size follows a historical trend, although it is conducive to reducing total carbon emission in the long run. The findings indicate that environmental regulations to reduce fertilizer usages should be strengthened for carbon emission abatement in the early stage of large-scale farming transformation, which are also informative to other developing countries with small farm size.

Estimating nitrogen and sulfur deposition across China during 2005 to 2020 based on multiple statistical models

Abstract. Due to the rapid development of industrialization and a substantial economy, China has become one of the global hotspots of nitrogen (N) and sulfur (S) deposition following Europe and the USA. Here, we developed a dataset with full coverage of N and S deposition from 2005 to 2020, with multiple statistical models that combine ground-level observations, chemistry transport simulations, satellite-derived vertical columns, and meteorological and geographic variables. Based on the newly developed random forest method, the multi-year averages of dry deposition of oxidized nitrogen (OXN), reduced nitrogen (RDN), and S in China were estimated at 10.4, 14.4, and 16.7 kg N/S ha−1 yr−1, and the analogous numbers for total deposition were respectively 15.2, 20.2, and 25.9 kg N/S ha−1 yr−1 when wet deposition estimated previously with a generalized additive model (GAM) was included. The dry to wet deposition ratio (Rdry/wet) of N stabilized in earlier years and then gradually increased especially for RDN, while that of S declined for over 10 years and then slightly increased. The RDN to OXN deposition ratio (RRDN/OXN) was estimated to be larger than 1 for the whole research period and clearly larger than that of the USA and Europe, with a continuous decline from 2005 to 2011 and a more prominent rebound afterwards. Compared with the USA and Europe, a more prominent lagging response of OXN and S deposition to precursor emission abatement was found in China. The OXN dry deposition presented a descending gradient from east to west, while the S dry deposition a descending gradient from north to south. After 2012, the OXN and S deposition in eastern China declined faster than the west, attributable to stricter emission controls. Positive correlation was found between regional deposition and emissions, while smaller deposition to emission ratios (D/E) existed in developed eastern China, attributed to more intensive human activities and thereby anthropogenic emissions.

Global Transportation Decarbonization

Replacing fossil fuels in the name of decarbonization is necessary but will be particularly difficult due to their as-yet unrivaled bundle of attributes: abundance, ubiquity, energy density, transportability and cost. There is a growing commitment to electrification as the dominant decarbonization pathway. While deep electrification is promising for road transportation in wealthy countries, it will face steep obstacles. In other sectors and in the developing world, it’s not even in pole position. Global transportation decarbonization will require decoupling emissions from economic growth, and decoupling emissions from growth will require not only new technologies, but cooperation in governance. The menu of policy options is replete with grim tradeoffs, particularly as the primacy of energy security and reliability (over emissions abatement) has once again been demonstrated in Europe and elsewhere.

Current Advances in Green Governance and CO2 Emissions towards Sustainable Development

Energy and environmental studies (E&E) have faced a significant turning point due to the lack of reliability of the existing models, as well as the lack of policy governance. Most papers in E&E have adapted data envelope analysis due to its popularity, which is a result of its structure of having multiple inputs and outputs. However, due to its crucial weakness in statistical reliability, diverse new methodologies to gain better reliability have been developed, such as difference-in-difference and computational general equilibrium models, but they are still do not popular because the world has not shown significant progress in the abatement of carbon emissions. This comes not only from the lack of appropriate, precise research models, but also from a worldwide lack of governance. Most countries advocate for the necessity of E&E policies, yet their policies alone are not enough for sustainable performance, due to the lack of reliability and/or weakness of public–private partnerships. This Special Issue shall examine all of these new challenges to the methodologies, as well as the implications and suggestions arising from their empirical results.

Costs and effects of measures to reduce ammonia emissions from dairy cattle and pig production: A comparison of country-specific estimations and model calculations

Understanding the costs of emission abatement measures is essential for devising reduction efforts. It allows to identify cost-effective solutions to achieve target values set by international agreements or national policies. This work aims to summarize and discuss the current knowledge on costs and effects associated with selected ammonia (NH3) mitigation measures in livestock production through comparison of country-specific and model-estimated values. Often, large differences appear between the results of individual countries, also in comparison with model results that are generally better harmonized between countries. It seems that different system boundaries in cost assessments, but also different geographic and structural conditions create perceived as well as real cost differences, also caused by the variability of individual situations. Our results are robust with respect to identifying feeding strategies as the most cost-effective, but results for other mitigation options do not show any clear trends, thus making it difficult to distinguish further cost-effective solutions. We point out and discuss some key aspects which may affect estimates of national costs, leading to challenges with the interpretation of final results. Our study concludes that further and more consistent assessments (e.g. standardized protocols) are needed to improve the evaluation base for other individual abatement options, including options that are under development.

Low-carbon economic operation of integrated energy systems in consideration of demand-side management and carbon trading

Under the background of carbon emission abatement worldwide, carbon trading is becoming an important carbon financing policy to promote emission mitigation. Aiming at the emerging coupling among various energy sectors, this paper proposes a bi-level scheduling model to investigate the low-carbon operation of the electricity and natural gas integrated energy systems (IES). Firstly, an optimal energy flow model considering carbon trading is formulated at the upper level, in which carbon emission flow model is employed to track the carbon flows accompanying energy flows and identify the emission responsibility from the consumption-based perspective, and the locational marginal price is determined at the same time. Then at the lower level, a developed demand-side management strategy is introduced, which can manage demands in response to both the dynamic energy prices and the nodal carbon intensities, enabling the user side to participate in the joint energy and carbon trading. The bi-level model is solved iteratively and reaches an equilibrium. Finally, case studies based on the IEEE 39-bus system and the Belgium 20-node system illustrate the effectiveness of the proposed method in reducing carbon emissions and improving consumer surplus.

Climate, wind energy, and CO[formula omitted] emissions from energy production in Denmark

The dynamic relation between CO2 emissions and wind energy in Denmark is analyzed using a fractional cointegration approach, extended to accommodate covariates. The impact of climate and forces of demand on the potential of wind power production for emissions abatement is investigated. Emissions decline as temperature increases. Wind power production increases with precipitation and North Atlantic oscillations. Aggregate output matters for emissions in a manner consistent with an environmental Kuznets curve (EKC). Accounting for a seasonal trend, our main estimate of marginal CO2 emissions avoided (MEA) per MWh of wind energy produced is 0.16 tonnes, based on impulse responses. This estimate of the abatement potential of wind power is lower than values reported in the literature, but statistically significant, and robust to including climate and EKC variables. MEA is reduced by about one third by treating electricity prices as endogenous, and by one quarter by including emissions from combustion of biomass. However, formal exogeneity tests indicate that the main MEA estimate is not inflated due to left-out general equilibrium effects. Without covariates, estimated MEA is 0.07, and insignificant.

Drivers of alleviated PM2.5 and O3 concentrations in China from 2013 to 2020

Since 2013, the Chinese Government implemented “Clean Air Action” Phase I (2013–2017) and Phase II (2018–2020) consecutively to improve air quality. However, it remains unclear how these policies have impacted air quality since most studies merely focus on Phase I. In this study, we applied the Community Multiscale Air Quality (CMAQ) model to investigate variations of air quality in China during “Clean Air Action” Phases I and Phase II (2013–2020). Results show that PM2.5 is significantly reduced (-40%) across China except in summer. O3 concentration also decreases, but a 3% increase is found in the Beijing-Tianjin-Hebei (BTH) region. Emission changes play a dominant role in the reduction of PM2.5 (over 95%). The contributions from meteorology and emissions to O3 reduction are 46% and 54%, respectively. Our results suggest that a more effective emission abatement strategy should be formulated, aiming to control O3 and PM2.5 synergistically.

Achieving Synergies of Carbon Emission Reduction, Cost Savings, and Asset Investments in China’s Industrial Sector: Towards Sustainable Practices

This study aims to investigate the dynamic correlations among carbon emission reduction, total cost savings, and asset investments in the industrial sector in China. This study uses the panel vector autoregressive (PVAR) model and the generalized method of moments (GMM) model to obtain three conclusions based on Chinese industrial industry data from 2005–2019. (1) The interaction between carbon emission reduction and cost reduction is bidirectional. A carbon emission decrease can result in persistent cost cutting, while measures in shrinking costs lead to reducing carbon emissions with lasting effects. Moreover, carbon emission decline has strong inertia, while cost reduction is softer. (2) Green investment promotes reducing carbon emissions and is efficient and sustainable. Conversely, completing carbon reduction milestones will inhibit asset expansion in the subsequent period. (3) China’s industrial sector has already achieved the “synergy of emission reduction and cost decrease” development model. The transmission chain “asset investment–carbon emission decline–cost decrease–carbon emission abatement” has been established. Nonetheless, a gap remains between the mature cycle of decarbonization, cost saving, and effectiveness. Finally, it is recommended that the government focuses on the synergistic effect of carbon and cost reduction, encourages continuous green investment, and systematically organizes decarbonization actions. This study provides a basis for increasing the interest of companies in transitioning to a low-carbon economy, contributing to the simultaneous realization of green development and economic benefits.

Optimal financing strategy and contract design of supply chain with yield uncertainty under cap-and-trade regulation

PurposeThe purpose of the study is to investigate the financing channels and carbon emission abatement preferences of supply chain members, and further examine the optimal contract design of the retailer.Design/methodology/approachThis paper develops a low-carbon supply chain composed of one retailer and one manufacturer, in which the retailer provides trade credit to the manufacturer. Considering the cap-and-trade regulation, the manufacturer with uncertain yield makes decision on whether to invest in emission abatement. There are bank loan and trade credit to finance production for the manufacturer and green credit to finance emission abatement investment. Meanwhile, the retailer may provide the manufacturer with three kinds of contracts to improve emission abatement efficiency, namely, revenue sharing, cost sharing or both sharing.FindingsThe results show that the retailer prefers to offer financing service at lower interest rate, but trade (and green) credit financing is always optimal for manufacturer and supply chain. The investment in emission abatement is value-added to all players. The sharing contracts offered by the retailer at lower sharing ratios can realize Pareto improvement of the system regardless of the financing scheme. However, comparing with the revenue or cost sharing contract, the existence of optimal sharing ratios makes the both sharing contract more favorable to the retailer.Practical implicationsThe findings provide guidance for the emission-dependent manufacturer in financing and emission abatement decisions, as well as recommendations for the retailer to offer loan service and sharing contract.Originality/valueThis paper integrates green credit into bank loan or trade credit to analyze the financing decision of the manufacturer with uncertain yield and further considers the influence of three kinds of sharing contracts introduced by the retailer on improving operational performance.

A Survey on Fluorinated Greenhouse Gases in Taiwan: Emission Trends, Regulatory Strategies, and Abatement Technologies

Fluorinated greenhouse gases (F-gases), including hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6), and nitrogen trifluoride (NF3), are used in a variety of applications, but they are potent greenhouse gases (GHGs). Therefore, they have been blanketed into the list of items to be phased out under international protocols or treaties. During the desk research, the updated statistics of Taiwan’s National Inventory Report (NIR) were used to analyze the trends of F-gases (i.e., HFCs, PFCs, SF6, and NF3) emissions during the period of 2000–2020. Furthermore, the regulatory strategies and measures for the reduction of the four F-gas emissions will be summarized to be in accordance with the national and international regulations. With the rapid development in the electronics industry, the total F-gas emissions indicate a significant increase from 2462 kilotons of carbon dioxide equivalents (CO2eq) in 2000 to the peak value (i.e., 12,643 kilotons) of CO2eq in 2004. However, it sharply decreased from 10,284 kilotons of CO2eq in 2005 to 3906 kilotons of CO2eq in 2020 due to the ongoing efforts of the regulatory requirements and the industry’s voluntary reduction in time sequence. It was also found that the most commonly used method for controlling the emissions of F-gases from the semiconductor and optoelectronic industries in Taiwan is based on the thermal destruction-local scrubbing method.

Allocation of the Carbon Emission Abatement Target in Low Carbon Supply Chain Considering Power Structure

The proposal of China’s dual carbon strategy is not only a kind of pressure but also an opportunity for enterprises. Both upstream and downstream enterprises in the supply chain pay more attention to carbon emission reduction, and consumers are gradually turning to a low-carbon preference. How carbon reduction targets are allocated among supply chain members with different technical efficiency and market opportunities will directly affect supply chain performance and social welfare. Power structure is an important factor that dominates the decision-making of the supply chain, so we establish the low-carbon supply chain model under three different power structures: manufacturer-led, retailer-led, and power pairs between two parties. We study the government distribution decisions of carbon emissions reduction targets under different supply chain power structures and discuss the influence of supply chain power structures on carbon emissions reduction distribution decisions and social welfare. The study found that if the carbon emissions reduction target increases, the government will adjust the allocation strategy to increase the proportion of enterprises whose emissions cuts have less impact on market demand. The study also found that the government will allocate more emissions reduction to enterprises with higher emissions reduction efficiency, and enterprises whose emissions reductions have a greater impact on market demand. When supply chain enterprises have equal power, the supply chain will have greater social welfare and market demand, but not necessarily greater supply chain profits.

Reduction of Typical Diesel NOx Emissions by SCR-NH3 Using Metal-Exchanged Natural Zeolite and SBA-15 Catalysts

In this work, the catalytic performance of clinoptilolite (CLIN) and SBA-15 catalysts, doped with Fe and Cu, was evaluated in the selective catalytic reduction of NO using NH3 as a reducing agent (SCR-NH3). Both Cu-CLIN and Fe-CLIN were obtained by ion-exchange using natural clinoptilolite zeolite originating from the Hrabovec deposit (northeast Slovakia region). Cu-SBA-15 and Fe-SBA-15 were prepared by impregnation into SBA-15 mesoporous synthesized silica. Standard catalytic activity tests were carried out on a bench-scale laboratory apparatus using a reaction mixture of a standard test. GHSV of 48,000 h−1 was adopted based on the space velocity of a real NH3-SCR catalyst for diesel vehicles (100–550 °C). All Cu-doped samples showed better NO conversion values than Fe-doped samples. Clinoptilolite catalysts were more active than those based on SBA-15. Maximum NO conversions of about 96% were observed for Cu-CLIN and Fe-CLIN at 350–400 °C, respectively. Moreover, Fe-CLIN also showed higher stability in the presence of SO2 and water steam at 350 °C. These results demonstrate the potential of metal-doped natural clinoptilolite to be used as cost-effective catalysts applied to the abatement of NOx emissions generated in automotive combustion processes.

U.S. Re-entry into the 2015 Paris Climate Agreement and Implications for the EU, Korea, China, and Japan: A CGE Approach

Purpose - With renewed greenhouse gas (GHG) emissions, abatement commitments and the rejoining of the Paris Climate Agreement of 2015 by the U.S., this study assesses the impact of carbon dioxide (CO₂) emissions reduction, and the opportunity cost of the U.S. in implementing its nationally determined commitments (NDCs).
 Design/Methodology/Approach - The study employs the GTAP-E model, an extension of the static GTAP model with CO₂ emissions trading, and GTAP DB version 10A with a base year of 2014. Model implementation includes a baseline scenario that projects the global economy from 2014 to 2030, and four policy scenarios representing the implementation of U.S. NDC targets without and with emissions trading.
 Findings - Simulation results suggest that CO₂ emissions reduction with trading significantly lowers the emissions abatement cost compared to CO₂ emissions reduction with no trading. Furthermore, the study finds that CO₂ emissions reduction leads to a drop in industry output by all energy and most non-energy sectors. Simulation results illustrate that CO₂ emissions reduction by the U.S. significantly affects most of its trading partners’ real GDPs, welfare, export and import flows, and industry outputs.
 Research Implications - The study provides a comprehensive impact assessment of global CO₂ emissions reduction, including U.S. contributions to addressing climate change. Moreover, the study has quantified the opportunity cost the U.S. will likely pay for meeting its NDC targets, and the likely impact of CO₂ emissions reduction by the U.S. on its major trading partners, especially the EU, Korea, Japan, and China.