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Addressing climate change demands, energy security and resilience has necessitated replacing conventional fossil-based fuels with zero and carbon-neutral fuels/energy carriers. The most immediate solution is the partial and progressive substitution of conventional fuels in transportation. The effects of partially substituting gasoline with ammonia/hydrogen (NH 3 /H 2) mixtures in a spark ignition (SI) engine are investigated in this paper. The utilization of NH 3 /H 2 mixtures is a promising avenue of research since they can be produced from on-board NH 3 reforming, utilising heat energy that is recovered from hot exhaust gases. Experimental results indicate that adding NH 3 /H 2 enabled stable engine operation at lean conditions (λ = 1.4), resulting in reduced carbon-based emissions due to the non-carbon nature of NH 3 /H 2. Utilising an integrated approach that combined a hemispherical flame geometry model with a thermodynamic model, has revealed that the introduction of NH 3 /H 2 significantly enhanced the combustion speed during the initial phase and further improved combustion efficiency. However, nitrogen-based emissions such as NO and NO 2 increased. This work also assessed the performance of a conventional three-way catalyst (TWC) and a double-function ammonia slip catalyst (ASC) in mitigating emissions. The TWC effectively controlled carbon-based emissions and NO under stoichiometric conditions but exhibited reduced efficiency under lean conditions, especially with NH 3 present. The ASC demonstrated high NH 3 conversion efficiency even at low temperatures, making it suitable for engine start-up and warm-up phases. Under steady-state conditions with artificially increased NH 3 /NO X ratios, a significant reduction in NOx emission was achieved with the ASC. However, high NH 3 /NO X ratios increased nitrous oxide (N 2 O) formation and NH 3 slip. • A combined NH 3 /H 2 combustion study was carried out with a prototype catalyst aftertreatment system. • NH 3 /H 2 blend in gasoline enables lean combustion but raises NO X emissions. • Combustion models show H 2 boosts initial phase burn rates. • TWC lacks N-based abatement capacity in terms of lean and NH 3 presence. • ASC efficiency increases with temperature but worsens with decreasing NH 3 /NO X ratio. [ABSTRACT FROM AUTHOR]

Energy conservation associated with hibernation is maximized at the intersection of low body temperature (Tb), long torpor bouts, and few interbout arousals. In the arctic ground squirrel (Urocitellus parryii), energy conservation during hibernation is best achieved at ambient temperatures (Ta) around 0 °C; however, they spend the majority of hibernation at considerably lower Ta. Because arctic ground squirrels switch to mixed fuel metabolism, including protein catabolism, at extreme low Ta of hibernation, we sought to investigate how microbial urea-nitrogen recycling is used under different thermal conditions. Injecting squirrels with isotopically labeled urea (13C/15N) during hibernation at Ta's of − 16 °C and 2 °C and while active and euthermic allowed us to assess the ureolytic activity of gut microbes and the amount of liberated nitrogen incorporated into tissues. We found greater incorporation of microbially-liberated nitrogen into tissues of hibernating squirrels. Although ureolytic activity appears higher in euthermic squirrels, liberated nitrogen likely makes up a smaller percentage of the available nitrogen pool in active, fed animals. Because non-lipid fuel is a limiting factor for torpor at lower Ta in this species, we hypothesized there would be greater incorporation of liberated nitrogen in animals hibernating at − 16 °C. However, we found higher microbial-ureolytic activity and incorporation of microbially-liberated nitrogen, particularly in the liver, in squirrels hibernating at 2 °C. Likely this is because squirrels hibernating at 2 °C had higher Tb and longer interbout arousals, a combination of factors creating more favorable conditions for gut microbes to thrive and maintain greater activity while giving the host more time to absorb microbial metabolites. [ABSTRACT FROM AUTHOR]

The Regional Greenhouse Gas Initiative (RGGI) regulates CO2 emissions from the power sector in the northeastern states of the U.S. Its effectiveness has been criticized due to the low CO2 allowance price and limited price variation, especially in the early years. Using a model that accounts for intertemporal constraints, this paper studies how firms react to weak CO2 emission regulations. The results show that the RGGI policy has helped decrease the total CO2 emissions by at least 4.73%. An additional $1/ton increase in permit price reduces the total CO2 emissions by 1.85%. CO2 can be reduced by 23.50% if carbon is priced at $15/ton. Slight evidence of fuel switching from coal to natural gas is found. [ABSTRACT FROM AUTHOR]

[Display omitted] Achieving net-zero CO 2 emissions is the current main focus of China's carbon neutrality goal. However, non-CO 2 greenhouse gases (GHGs) are more powerful climate forcers, making their emission reduction an opportunity to rapidly mitigate future warming. Here, we evaluate non-CO 2 mitigation potentials, costs and climate benefits in the context of China's carbon neutrality goals. The assessment is conducted by coupling the integrated assessment model GCAM with a climate emulator. The findings indicate that mitigation technologies can largely reduce fluorinated gas emissions from industrial sectors, but long-term non-CO 2 reductions of energy sector activities rely heavily on fuel switching. Furthermore, the cumulative costs of deploying non-CO 2 mitigation technologies are projected to be less than 10 % of the total costs of achieving carbon neutrality from 2020 to 2060. If non-CO 2 mitigation measures are included in the overall mitigation portfolio, the benefits of avoided warming would by far outweigh the total mitigation cost increase. Our results thus highlight that incorporating a wider suite of GHGs into climate change mitigation strategies can enhance the cost-effectiveness of mitigation efforts. [ABSTRACT FROM AUTHOR]

Equine recurrent uveitis (ERU) is a spontaneously occurring autoimmune disease and one of the leading causes of blindness in horses worldwide. Its similarities to autoimmune-mediated uveitis in humans make it a unique spontaneous animal model for this disease. Although many aspects of ERU pathogenesis have been elucidated, it remains not fully understood and requires further research. CD4+ T cells have been a particular focus of research. In a previous study, we showed metabolic alterations in CD4+ T cells from ERU cases, including an increased basal oxygen consumption rate (OCR) and elevated compensatory glycolysis. To further investigate the underlying reasons for and consequences of these metabolic changes, we quantified reactive oxygen species (ROS) production in CD4+ T cells from ERU cases and compared it to healthy controls, revealing significantly higher ROS production in ERU-affected horses. Additionally, we aimed to define mitochondrial fuel oxidation of glucose, glutamine, and long-chain fatty acids (LCFAs) and identified significant differences between CD4+ T cells from ERU cases and controls. CD4+ T cells from ERU cases showed a lower dependency on mitochondrial glucose oxidation and greater metabolic flexibility for the mitochondrial oxidation of glucose and LCFAs, indicating an enhanced ability to switch to alternative fuels when necessary. [ABSTRACT FROM AUTHOR]

Extensive research has been conducted on the transition to environmentally friendly fuels in developed countries worldwide. However, there has been a significant lack of attention given to this crucial topic in developing countries. The study aims to bridge this gap by conducting a comprehensive analysis of the existing obstacles and prospects associated with transitioning to hydrogen fuel, with a specific focus on Vietnam. To achieve this objective, a rigorous SWOT (Strengths, Weaknesses, Opportunities, and Threats) analysis approach is employed, drawing upon an extensive literature review and the insights of selective experts in the field. Additionally, the Analytic Hierarchy Process (AHP) is utilized to effectively prioritize the identified factors from the SWOT analysis through eigenvalue calculation. As a result, the weaknesses are the highest first-class priority factors, with "Dedicated infrastructure for the transition to hydrogen fuel" and "Technological capacity for converting to hydrogen fuel" taking the next priorities in the second class. The outcomes of this research serve as a valuable resource for Vietnam and other developing countries, guiding policy-making and practical applications in the pursuit of transitioning to hydrogen fuel. Furthermore, this paper establishes a robust framework that can guide future studies in this specific area of research. [ABSTRACT FROM AUTHOR]

Biodiesel generated from oils and fats composed of fatty acid alkyl esters is a potential substitution for fossil fuels, gaining attention as the demand for sustainable energy grows. Enzymatic transesterification has emerged as a promising method for biodiesel production due to the low energy required, easy glycerol recovery and compatibility with various feedstocks. This method also offers high specificity and operates under mild reaction conditions. However, limitations such as enzyme production cost, low product yield, and low stability under harsh conditions, have hindered the progress of biocatalysis. Protein engineering has emerged as an important strategy to overcome these limitations, particularly through rational design. Rational design approaches are advantageous in lipase engineering, due to accessible experimental tools and existing knowledge of lipase structure and function. Site-directed mutagenesis has been applied to improve stability, substrate specificity, methanol tolerance, and catalytic efficiency of lipase by introducing molecular interactions like hydrogen bonds and disulfide bridges as well as improved lid flexibility by mutations at the lid or lid swapping. This targeted approach allows for the precise modification of amino acid residues, optimizing lipase for better performance, which is crucial for efficient biodiesel production. [ABSTRACT FROM AUTHOR]

Biomass, as a renewable and clean energy source, can be utilized for partial fuel substitution through the process of fast pyrolysis, which converts it into bio-oil. However, the presence of naturally occurring metallic elements in biomass has an adverse effect on its pyrolysis process. In this study, the aqueous fraction separated from biomass pyrolysis liquid, characterized by its acidity and high water content, was used for washing pretreatment of walnut shells. The analysis of the treated walnut shells was meticulously conducted employing techniques, including inductively coupled plasma mass spectrometry, thermogravimetric analyzer, and pyrolyzer-gas chromatography/mass spectrometer. The results indicate that this method has a positive influence on the composition and structure of walnut shells, with removal rates of 75% for Na and 45% for K. The thermal decomposition peak on the thermogravimetric curve became more distinct and shifted to higher temperatures. In additionally, the maximum weight loss rate increases to 0.83 °C/%, and the final residue decreased to 17%. The yields of acids and ketones in the pyrolysis products decreased by 49.43% and 53.69%, respectively. Meanwhile, the yields of phenols and sugars increased by 17.43% and 80%, respectively. Furthermore, the influence of pyrolysis conditions (temperature and time) on the pyrolysis products was investigated, and the optimal pyrolysis conditions (500 °C and 20 s) were determined. Therefore, washing pretreatment of the aqueous part of pyrolysis liquid can effectively enhance the quality of biomass and pyrolysis products. It not only contributes to improving the utilization value of pyrolysis liquid by-product but also holds practical significance for the sustainable use of resources and energy production. [ABSTRACT FROM AUTHOR]

A cost–benefit analysis of air pollution reduction measures in maritime transport systems can support the sustainability commitments of the industry and validate the related economic incentives. However, a systematic cost–benefit analysis approach has not yet been framed, as data availability and resources are limited. This study explores an alternative cost–benefit estimate approach to reduce air pollution in shipping based on a broad review and applies it to a case study regarding the domestic emission controls of Xiamen shipping. The results show that switching to a fuel with a maximum allowable fuel sulphur content of 1.5% to 0.5% for cargo ships and other vessels leads to more than nine times the external benefits to costs, while switching to a fuel with less than 0.5% sulphur content may lead to below-cost external benefits; the benefits/cost ratio based on shore power is 3.14. The proposed approach contributes to estimating not only the input costs but also their external benefits to fit the externality of sustainability actions. In the future, more site-specific factors and parameters and more case studies are recommended to improve the research reliability and accuracy as well as enrich the knowledge base for shipping sustainability development. [ABSTRACT FROM AUTHOR]

The current energy and environmental problems demand the replacement of fossil fuels with renewable fuels. Research shows that hydrogen-enriched CNG fuels enhance the thermal efficiency of diesel engines while reducing gaseous emissions. This experimental work investigates the performance and emissions parameters of a diesel engine in dual fuel mode with hydrogen-enriched Bio-CNG (HBCNG). It is performed on a single-cylinder, four-stroke common rail direct injection (CRDI) diesel engine at 1500 rpm and 3.5 kW. The outcomes of this experiment are compared to a neat diesel operation. It is observed that at low load with 30% gaseous fuel substitution (GFS), brake thermal efficiency decreases by 13.70% and 15.53% for hydrogen and BCNG-enriched diesel, respectively. Similarly, at medium load, with the gaseous mixture of 40% H 2 and 60% BCNG co-combusted with 60% diesel, the BTE improves by 15.83%. At high load, 40% gaseous fuel mixture (40% H 2 + 60% BCNG) combustion with diesel results in 21.25% enhanced BTE. Moreover, at the same load condition and GFS, emissions of HC increase by 41.59%, CO decreases by 30%, CO 2 decreases by 55.36%, and NO x decreases by 25.94%. • The experiment is performed on a common rail direct injection diesel engine. • Hydrogen and Bio-CNG enriched diesel are used as the fuel. • Hydrogen and Bio-CNG mixture proportion in diesel are varied between 0 and 40%. • The engine load is varied between 0 and 80%. • The performance and emission parameters enhanced for 40% gaseous fuel mixture. [ABSTRACT FROM AUTHOR]

Low-carbon fuels, feedstocks, and energy sources can play a vital role in the decarbonization of clinker production in cement manufacturing. Fuel switching with renewable natural gas, green hydrogen, and biomass can provide a low-carbon energy source for the high-temperature process heat during the pyroprocessing steps of clinker production. However, up to 60% of CO2 emissions from clinker production are attributable to process-related CO2 emissions, which will need the simultaneous implementation of other decarbonization technologies, such as carbon capture. To evaluate the potential of fuel switching and carbon capture technologies in decarbonizing the cement industry, a study of the facility-level CO2 emissions is necessary. This study evaluates the potential for using a single low-carbon fuel as an energy source in clinker production for cement manufacturing compared to conventional clinker production (which uses a range of fuel mixes). In addition, conventional carbon capture (operated with natural gas-based steam for solvent regeneration) and electrified carbon capture configurations were designed and assessed for net-zero emission targets. Carbon emissions reductions with and without biogenic emissions credits were analyzed to ascertain their impact on the overall carbon accounting. Results show that carbon emissions intensity of cement can vary from 571 to 784 kgCO2eq/metric ton of cement without carbon capture and from 166.33 to 438.66 kgCO2eq/metric ton of cement with carbon capture. We find that when biogenic carbon credits are considered, cement production with a sustainably grown biomass as fuel source coupled with conventional carbon capture can lead to a net-negative emission cement (−271 kgCO2eq/metric ton of cement), outperforming an electrified capture design (35 kgCO2eq/metric ton of cement). The carbon accounting for the Scope 1, 2, and biogenic emissions conducted in this study is aimed at helping researchers and industry partners in the cement and concrete sector make an informed decision on the choice of fuel and decarbonization strategy to adopt. [ABSTRACT FROM AUTHOR]

The US Pulp and Paper (P&P) industry heavily relies on fossil sources, with lime kiln operations posing a significant challenge for achieving zero on-site fossil emissions. This study assesses the greenhouse gas (GHG) reduction potential and costs associated with alternative fuels in lime kiln operations for linerboard production. Various options, including bio-based fuels including pulverized biomass, gasification of biomass, crude tall oil, bio-methanol, and traditional fuels such as fuel oil and petcoke, were analyzed through detailed process simulations and Life Cycle Assessment. Results indicate that per ton of product, 2,789 kg of CO2-eq is emitted, with 69% being biogenic CO2 and 31% fossil CO2-eq. Notably, replacing the natural gas boiler with a biomass boiler reduces Global Warming Potential (GWP) by 41%, while switching lime kiln fuel to biofuels achieves a 5.5% reduction. Combining a biomass boiler with pulverized biomass fuel use in the lime kiln yields a substantial 93.1% reduction in Scope 1 and 2 emissions, at a cost of $76/ton of CO2-eq avoided. [ABSTRACT FROM AUTHOR]

Cement production is linked to heavy environmental load with exigences for reduction and substitution of raw materials and energy demands/sources. Recently, with the potential commercial discovery of natural gas (NG) reserves in Lebanon, discussions on the viability of fuel-switching, from petcoke (kiln processes) and heavy fuel oil (HFO) (reciprocating engines) to NG in the cement sector emerged. To that aim three alternative scenarios (SCx) were suggested: shifting petcoke to NG in kiln processes (SC1); shifting reciprocating engines from HFO to NG (SC2); shifting kiln processes and reciprocating engines to NG (SC3). An economic analysis indicated that SC2 is the only viable option. This paper presents a new combination of life cycle impact assessment (LCA) and monetization to quantify environmental impacts for the decision-making processes, within the Lebanese context. The LCA was conducted using primary data and SimaPro v8.5.2.0. The functional unit (FU) was 1 kg of cement. IPCC 2013 GWP 100a V1.03, Cumulative Energy Demand (CED) V1.10 ReCiPe 2016 E v1.02 impact assessment and Stepwise2006 (V1.05.3) monetary valuation methods were used. Results indicated that all scenarios lead to a reduced carbon footprint: 0.016 kgCO2eq., 0.0008 kgCO2eq. and 0.0168 kgCO2eq. for SC1, SC2 and SC3, respectively, from the baseline 1.0327 kgCO2eq.. The baseline CED was 5.06 MJ, and 4.5 MJ, 4.91 MJ and 4.35 MJ for SC1, SC2, and SC3, respectively. SC3 had the lowest environmental burden, followed by SC1 and SC2. Damage assessment results indicated that all alternative scenarios reduce environmental damage, while SC3 brought the highest benefit followed by SC1 and SC2, respectively. Monetization results/ FU indicated a cost burden of 25.54 US¢, 24,64 US¢, 25.5 US¢ and 24.6 US¢ for baseline, SC1, SC2 and SC3, respectively. Finally, the best fit option, after internalizing the environmental cost, shifted from SC2 to SC3 indicating the merits of combining LCA and monetization into decision-making processes. [ABSTRACT FROM AUTHOR]

As the backbone of the international seaborne trade, the pollution and emission from shipping are highly concerned by governments and international organizations as well. The International Maritime Organization has designated five emission control areas (ECAs) to limit sulfur oxides emissions of ships. Meanwhile, the European Union has included the shipping industry in the EU Emission Trading System since 2024 to control their carbon emissions. The strategies like switching fuel, installing scrubber or detour, are commonly used to comply with the ECA regulation, but they may increase carbon emissions and possibly incur extra carbon trading cost. In this case, the shipping company should investigate the influence of marine emission trading system (METS) on emission reduction strategies used under ECA regulation. Therefore, this paper focuses on this problem and formulates it as a mixed-integer nonlinear programming model. Several numerical experiments are conducted to show the applicability of the proposed model. The results show that ship's detour behavior is inevitable under the ECA regulation, which incurs more carbon emissions. When METS regulation is not considered, the optimal emission reduction strategy is installing scrubber. In contrast, when METS regulation is considered, the optimal choice may be installing scrubber or fuel switching depending on different sailing route, which indicates the effect of METS on ship emission reduction strategy. Moreover, the fleet deployment and sailing speed of scrubber installation strategy are affected by METS regulation, while the strategies of fuel switching and using LNG-powered ship are almost unaffected. This indicates that installing scrubber is more easily affected by emission control policies. • Jointly optimize the ship's energy strategy and scheduling under ECA regulation. • Investigate the effect of METS on optimal solutions under ECA regulation. • Shipping company should re-optimize his energy strategy and ship scheduling plan under both ECA and METS regulation. [ABSTRACT FROM AUTHOR]

To successfully implement mitigation policies, it is first needed to identify the factors that contribute to carbon emissions. Based on the extended Kaya identity approach, this study investigates the driving factors of energy‐related carbon emissions in Pakistan from 1990 to 2019 using the multiplicative LMDI‐I decomposition technique with no residual term. The decomposition results reveal that the population and affluence contributed significantly to accelerating carbon emissions from energy consumption across all the sub‐periods. The cumulative effect of population size increased to 2.286 times in 2019, far greater than the impact of other factors. The cumulative effect of economic activity per person reached 1.566 in 2019. The impact of fuel quality and energy intensity is relatively minor (as the index value is less than one) most of the time. The cumulative effect of renewable energy penetration has increased from 0.998 in 1990 to 1.034 in 2019 due to the country's less mature renewable energy technologies. Fossil fuel switching is a factor that reduces carbon emissions, as the index value decreased from 0.945 in 1990 to 0.918 in 2019. The results of the study contain helpful information for lowering carbon emissions. [ABSTRACT FROM AUTHOR]

Energy poverty has been a major concern for sub-Saharan Africa (SSA). Government efforts predominantly focus on expanding national grid networks to address energy needs. Less attention has been given to alternative forms of co-provision of cooking and lighting energy, although they are critical elements of urban energy governance. Using the analytical concept of socio-technical heterogeneity, this study draws insights from empirical data in Accra to understand everyday energy configurations used by urban dwellers outside the formal state-led infrastructures. It was found that, for electricity, households adopt heterogeneous configurations, including electricity theft, meter sharing, illegal expansion of the grid, self-help solar PV, use of small diesel generators, back-up power appliances, and service phone charging vendors. In terms of cooking energy, households adopt fuel switching, use of multiple cooking stoves, and use of improved cooking stoves. These co-provisions reflect a governance failure and, at the same time, fill critical provision gaps. Heterogeneous configurations also come with socioeconomic and environmental externalities. The findings suggest a need for decentralisation and integration of context-specific, place-based and situated forms of co-provision or heterogeneous configuration into urban energy planning and governance. [ABSTRACT FROM AUTHOR]

Beige fat activation involves a fuel switch to fatty acid oxidation following chronic cold adaptation. Mitochondrial acyl-CoA synthetase long-chain family member 1 (ACSL1) localizes in the mitochondria and plays a key role in fatty acid oxidation; however, the regulatory mechanism of the subcellular localization remains poorly understood. Here, we identify an endosomal trafficking component sortilin (encoded by Sort1) in adipose tissues that shows dynamic expression during beige fat activation and facilitates the translocation of ACSL1 from the mitochondria to the endolysosomal pathway for degradation. Depletion of sortilin in adipocytes results in an increase of mitochondrial ACSL1 and the activation of AMPK/PGC1α signaling, thereby activating beige fat and preventing high-fat diet (HFD)-induced obesity and insulin resistance. Collectively, our findings indicate that sortilin controls adipose tissue fatty acid oxidation by substrate fuel selection during beige fat activation and provides a potential targeted approach for the treatment of metabolic diseases. Beige fat activation involves a fuel switch to fatty acid oxidation following chronic cold adaptation. Here, the authors show that Sortilin in adipose tissues facilitates the translocation of ACSL1 from the mitochondria to the endolysosomal pathway for degradation, which controls adipose tissue fatty acid oxidation and substrate fuel selection during beige fat activation. [ABSTRACT FROM AUTHOR]

Assessing carbon emission reduction potential is vital for achieving carbon peak and neutrality in the maritime sector. In this study, we proposed a universal framework for assessing the effectiveness of different measures on carbon emission reduction from ships, including port and ship electrification (PSE), ship speed optimization (SSO), and clean fuel substitution (CFS). Firstly, the projection method of future ship traffic flows and activity levels relies on a neural network, and the ARIMA model was proposed. Then, the potential of various emission reduction measures was detailed and analyzed under different intensity scenarios. The proposed model was applied to Wuhan port, the results indicate that CFS is the most effective for long-term decarbonization, potentially achieving a carbon peak by 2025 under an aggressive scenario. For the short to medium term, PSE is favored due to technical maturity. SSO primarily delays emissions growth, making it a suitable auxiliary measure. These findings guide emission reduction strategies for ports, fostering green and sustainable shipping development. [ABSTRACT FROM AUTHOR]

Fuel switching is the most mature, reliable, and economical technology for ship operators to comply with regulations of sulfur emission control area (SECA), and will remain so for the next few years. Under SECA regulations, this paper tries to optimize liner shipping operation by integrating ship deployment, schedule design, and speed optimization while considering transit time. Specifically, a mixed integer nonlinear programming model was built to minimize operating costs, and fully guarantee the logic and superiority of the existing liner shipping network. A two-stage algorithm based on ɛ outer approximation estimation and enumeration was designed, and a backtracking algorithm was provided for determining initial port combinations in large-scale instances. After that, a case study on the Orient Overseas Container Line was carried out to verify the operability and flexibility of our method. The optimized strategy refines the existing network by adjusting initial port combinations, enhancing speed, and expanding new ship deployments. To mitigate the impact of rising port demurrage fees, liner companies are reducing transshipment penalty costs. While easing connecting time window (CTW) restrictions offers limited benefits, optimizing speed and loosening CTW can reduce operational costs by approximately 2–5%, helping liner companies navigate the fluctuating fuel market post-Covid. [ABSTRACT FROM AUTHOR]

The global need for petroleum and its dwindling availability throughout the world demand an alternative fuel. Hydrogen-enriched algal biodiesel (ABD) is a potential option against conventional fuels due to its availability and positive effects on performance and emissions. Azolla pinnata algae is a high-yield fuel with reduced adverse impacts on the environment, requiring 2–5 days to double its biomass. This research work involves post-experimentation modeling to assess the performance and emissions of a CRDI diesel engine using a hydrogen-enriched blended fuel of Azolla pinnata ABD. Response surface methodology has been applied to optimize the load, fuel blend, and hydrogen gas substitution for performance and emissions characteristics. The ABD and hydrogen gas are varied between 0 and 40% in the pilot fuel for loads between 0 and 80%. The model indicates that the optimized load, blend, and hydrogen fuel substitution for this research are, respectively, 80%, 40%, and 40%. At the above-mentioned optimized parameters, the optimized values of BTE, CO, CO 2 , HC, and NO x are found to be 30.90%, 19.99 g/kWh, 288.89 g/kWh, 0.21 g/kWh, and 1.57 g/kWh, respectively. Adequacy precision greater than 4 and a percentage error between predicted and experimental values less than 5% indicate the model's ability to predict performance and emissions characteristics eventually. [Display omitted] • The experiment is performed on a CRDI dual-fuel diesel engine. • Diesel and biodiesel (Azolla pinnata) blends enriched with H 2 are used as fuel. • Experimental data has been used for developing mathematical & RSM models. • BTE & emissions are optimized for 80% load, 40% blend, and 40% GFS experimentally. • With a percentage error of less than 5%, RSM validated the experimental results. [ABSTRACT FROM AUTHOR]

Mandatory use of low-sulfur fuel according to the global sulfur limit regulation has reduced the emissions of SO2 and particulate matter (PM) significantly on ships, and it also leads to a very large uncertainty in volatile organic compound (VOC) emissions. Therefore, an on-board test of VOCs from nine typical cargo ships with low-sulfur fuels in China was carried out in this study. Results showed that the emission factor of VOCs (EFVOCs) varied largely from 0.09 to 3.01 gkg-1 of fuel, with domestic coastal cargo ships (CCSs) having the highest level, followed by inland cargo ships (ICSs) and ocean-going vessels (OGVs). The switch of fuels from heavy fuel oil (HFO) to diesel increased EFVOCs by 48 % on average, which enhanced both O3 and secondary organic aerosol (SOA) formation potential, especially for OGVs. Besides, the use of low-sulfur fuels for OGVs also led to a significant increase in naphthalene emission. These indicated that the implementation of a global ultra-low-sulfur oil policy in the near future needs to be optimized. Moreover, aromatics were the most important common contributors to O3 and SOA in ship exhausts, which need to be controlled as a matter of priority. It was also found that the benzene, toluene, and ethylbenzene ratio of 0.5:0.3:0.2 on average could be considered a diagnostic characteristic to distinguish ship emissions from other emission sources. [ABSTRACT FROM AUTHOR]

With a specific end goal to take care of the worldwide demand for energy, broad research is done to create alternative and cost-effective fuel. The fundamental goal of this examination is to investigate the performance, emissions and vibration characteristics of a single cylinder four stroke diesel engine, working in dual fuel mode with biodiesel of Karanja oil ((BKO) as a renewable fuel and hydrogen (H 2) as gaseous fuel on low (2%), intermediate between medium-high (53%) and high (69%) load conditions. Biodiesel of Karanja oil as 20% biodiesel and 80% diesel known as BKO20, while 30% biodiesel and 70% diesel known as BKO30. With 25% introduction of gaseous fuel (H 2) and biodiesel (10%–40%) along with diesel showed an increase in brake thermal efficiency (BTE), 85.23%, 10.62% and 19.4% respectively as compared to parent diesel fuel operation. As far as emission is concerned, oxides of nitrogen (NO x) decreased on higher load conditions with a variation of biodiesel (10%–50%) in comparison to low load condition. However, the formation of monoxide (CO), carbon dioxide (CO 2) and un-burnt hydrocarbon (HC) decreases along with BKO50 using 25% hydrogen fuel substitution at high (69%) load conditions. • H 2 (25%) along with Karanja oil (40%) substituted by 65% diesel fuel. • Brake thermal efficiency (85.23%) optimum with Karanja oil (10%) by H 2 (25%) fuel. • Emission, combustion and its performance formed superior features. • NO x formation decreased as biodiesel substitution increases up to 50%. [ABSTRACT FROM AUTHOR]

Marangoni self‐propulsion refers to motion of liquid or solid driven by a surface tension gradient, and has applications in soft robots/devices, cargo delivery, self‐assembly etc. However, two problems remain to be addressed for motion control (e.g., ON–OFF) with conventional surfactants as Marangoni fuel: (1) limited motion lifetime due to saturated interfacial adsorption of surfactants; (2) in‐ situ motion stop is difficult once Marangoni flows are triggered. Instead of covalent surfactants, supra‐amphiphiles with hydrophilic and hydrophobic parts linked noncovalently, hold promise to solve these problems owing to its dynamic and reversible surface activity responsively. Here, we propose a new concept of 'supra‐amphiphile fuel and switch' based on the facile synthesis of disodium‐4‐azobenzene‐amino‐1,3‐benzenedisulfonate (DABS) linked by a Schiff base, which has amphiphilicity for self‐propulsion, hydrolyzes timely to avoid saturated adsorption, and provides pH‐responsive control over ON‐OFF motion. The self‐propulsion lifetime is extended by 50‐fold with DABS and motion control is achieved. The mechanism is revealed with coupled interface chemistry involving two competitive processes of interfacial adsorption and hydrolysis of DABS based on both experiments and simulation. The concept of 'supra‐amphiphile fuel and switch' provides an active solution to prolong and control Marangoni self‐propulsive devices for the advance of intelligent material systems. [ABSTRACT FROM AUTHOR]

Carbohydrates and lipids provide the majority of substrates to fuel mitochondrial oxidative phosphorylation. Metabolic inflexibility, defined as an impaired ability to switch between these fuels, is implicated in a number of metabolic diseases. Here, we explore the mechanism by which physical inactivity promotes metabolic inflexibility in skeletal muscle. We developed a mouse model of sedentariness, small mouse cage (SMC), that, unlike other classic models of disuse in mice, faithfully recapitulated metabolic responses that occur in humans. Bioenergetic phenotyping of skeletal muscle mitochondria displayed metabolic inflexibility induced by physical inactivity, demonstrated by a reduction in pyruvate-stimulated respiration (JO2) in the absence of a change in palmitate-stimulated JO2. Pyruvate resistance in these mitochondria was likely driven by a decrease in phosphatidylethanolamine (PE) abundance in the mitochondrial membrane. Reduction in mitochondrial PE by heterozygous deletion of phosphatidylserine decarboxylase (PSD) was sufficient to induce metabolic inflexibility measured at the whole-body level, as well as at the level of skeletal muscle mitochondria. Low mitochondrial PE in C2C12 myotubes was sufficient to increase glucose flux toward lactate. We further implicate that resistance to pyruvate metabolism is due to attenuated mitochondrial entry via mitochondrial pyruvate carrier (MPC). These findings suggest a mechanism by which mitochondrial PE directly regulates MPC activity to modulate metabolic flexibility in mice. [ABSTRACT FROM AUTHOR]

This review aims to dispel the myths, misinformation and fake facts about hydrogen burner flames in the literature. These are creating resistance the adoption of hydrogen for decarbonising heat. Trials of hydrogen heat in hydrogen villages have been opposed in the UK by outside groups generating unsubstantiated fears about the safety of the use of hydrogen and influencing Government policy on the decarbonisation of domestic and industrial heat. There are many myths about the use of hydrogen for heat (Hy4Heat), most of which relate to safety, which ignore all the work done under UK Government Hy4Heat contracts, that show that hydrogen will be as safe as natural gas (NG) in use, in domestic and industrial heat applications. Some claim that the manufacture of hydrogen from NG will generate more greenhouse gases (GHG) than burning it directly (Rosenow, 2022), which is shown to be not true for modern low plants. Domestic and industrial electricity is delivered by the electricity grid, which currently cannot operate without 35% of the electricity from NG fired combined cycle gas turbines (CCGT), as this fills in the supply gaps when the wind is low and the sky cloudy. This means that electric heat pumps are not zero carbon and are shown to have higher carbon emissions than hydrogen made from NG using the latest technology. In contrast hydrogen, can be manufactured from NG or by electrolysis directly by solar and wind farms, without any connection to the electricity grid and fed into the gas transmission system, with only relatively low cost modifications. Hydrogen burners can be designed to meet all current NOx standards and even have lower NOx than on NG and will not be allowed to emit higher NOx than for NG. Practical hydrogen burners for heat applications have orange flames and very visible not invisible, as many in the literature claim. The UK and other countries in 1900 - 1965 built coal gasification plants on a large scale to feed the gas grid with coal gas (about 40% hydrogen), then replaced the gas with natural gas in the 1965 - 1975 period, fuel switching to hydrogen is conventional gas engineering and achievable over a 10-15 year period. In the UK the gas grid in 2022 supplied 784TWh of energy compared with 320 TWh of electricity with only 99 TWh of this from solar/wind/hydro. It is obviously grossly misleading to say that gas energy can be replaced by increased solar/wind/hydro on any sensible timescale. Switching the 300 TWh of domestic heat from gas to electricity in addition to switching transport energy to electricity, cannot be met on the required timescale by increased solar/wind/hydro in the UK. Net zero can be met on a 10-15 year timescale if NG is switched to hydrogen, which enables net zero electricity, as well as net zero heat. [ABSTRACT FROM AUTHOR]

The measures needed to limit global warming pose a particular challenge to current fossil fuel exporters, who must not only decarbonise their local energy systems, but also compensate for the expected decline in fossil fuel revenues. One possibility is seen in the export of green hydrogen. Using Algeria as a case study, this paper analyses how different levels of ambition in hydrogen exports, energy efficiency and fuel switching affect the cost-optimal expansion of the power sector for a given overall emissions reduction path. Despite falling costs for photovoltaics and wind turbines, the results indicate that in countries with very low natural gas prices, such as Algeria, a fully renewable electricity system by 2050 is unlikely without appropriate policy measures. The expansion of renewable energy should therefore start early, given the high annual growth rates required, which will be reinforced by additional green hydrogen exports. In parallel, energy efficiency is a key factor as it directly mitigates CO2 emissions from fossil fuels and reduces domestic electricity demand, which could instead be used for hydrogen production. Integrating electrolysers into the power system could potentially help to reduce specific costs through load shifting. Overall, it seems advisable to analyse hydrogen exports together with local decarbonisation in order to better understand their interactions and to reduce emissions as efficiently as possible. These results and the methodology could be transferred to other countries that want to become green hydrogen exporters in the future and are therefore a useful addition for researchers and policy makers. • The required strong capacity expansion for PV and wind is challenging, but feasible. • "Energy efficiency first" benefits both the local energy transition and H2 exports. • Fully renewable power systems require a suitable political framework. • Higher hydrogen exports might help to reduce the specific power system cost. • Fossil capacity expansion must be stopped to avoid lock-ins and higher future costs. [ABSTRACT FROM AUTHOR]

To attain a net zero-carbon emissions energy system, the grid needs dispatchable and flexible power production capable of responding to wind and solar energy variability. Hydrogen-fired gas turbines could play a role in meeting this requirement in the electricity grid; however, research and development are needed to assess the impact of the fuel change on these systems. This study aims to determine the effect of fuel switching on the cycle performance of a typical aero-derivative gas turbine, ranging from 25-35MW when combined with various steam-based bottoming cycles using Aspen Plus thermodynamic simulations. The gas turbine cycle's efficiency and net output power increased by about 2.26% and 5.24%, respectively, when fueled with hydrogen for the constant TIT control strategy compared with the base case. The other two control strategies—constant TOT and heat input—are also positive. The performance of the combined heat and power configurations, expressed by the fuel charged to power, is better for almost all the hydrogen-fired cases compared with the methane case. This implies that using hydrogen as fuel in the gas turbine and duct-firing requires less fuel to produce heat and electricity. Although hydrogen integration into the overall system may pose challenges with auxiliary equipment, storage, supply, and combustion, hydrogen as fuel shows promise in improving the performance of gas turbine combined heat and power units. • Hydrogen for GTs will be an enabler of low-carbon and flexible power production. • Switching to hydrogen enhances power and heat production in all operating strategies. • The GT performance improves with the hydrogen fraction for all operating strategies. • Hydrogen firing increases the operational flexibility of GT-based CHP configurations. [ABSTRACT FROM AUTHOR]

Relative humidity with respect to ice (RH i) is a key variable in the formation of cirrus clouds and contrails. We document its probability density function (PDF) using long-term Measurements of Ozone, Water Vapour, Carbon Monoxide and Nitrogen Oxides by In-Service Airbus Aircraft (MOZAIC) and the In-service Aircraft for a Global Observing System (IAGOS) observations over the period 1995–2022 in the upper troposphere (UT) and the lower stratosphere (LS) between 325 and 175 hPa. The characteristics of the RH i PDF differ in the UT and in the LS of the high-latitude regions (HLs) and mid-latitude regions (MLs) of the Northern Hemisphere. In the LS, this PDF decreases exponentially with increasing RH i. In the UT, it first increases exponentially in subsaturated conditions and then decreases exponentially in supersaturated conditions. Because of these different behaviors, the PDF for the combined UT and LS is bimodal. In contrast to the HLs and the MLs, the RH i PDF in the tropical troposphere decreases exponentially with increasing RH i. The different forms of PDF, in the tropics and in the higher-latitude regions, lead to a global PDF of RH i in subsaturated tropospheric conditions that is almost uniform. These findings invite caution when using MOZAIC and IAGOS measurements to calibrate large-scale simulations of RH i. The variability in RH i properties associated with that of temperature also has implications for the formation of contrails. We examined the impact of switching fuel (from kerosene to bioethanol or liquid hydrogen) on the frequency of contrail formation using the Schmidt–Appleman criterion. We show that bioethanol and, to a larger extent, liquid hydrogen would produce more contrails. The impact of a potential change from kerosene to these alternative fuels decreases with decreasing pressure but increases when moving from the higher latitudes of the Northern Hemisphere to the tropics. Finally, we emphasize that investigations of the impact on contrail occurrence frequency as a result of switching from fossil kerosene to more sustainable fuels must be carried out in various meteorological conditions. [ABSTRACT FROM AUTHOR]

This paper provides a comprehensive review of current strategies and technologies aimed at reducing nitrogen oxide (NOx) emissions from marine diesel engines and serves as a mechanism to summarize existing solutions. The scientific value of the paper lies in the comprehensive analysis of the approaches and offers new insights and an integrated framework that improves the scientific understanding and practical application of these technologies. The study synthesizes different approaches to NOx emission reduction, including selective catalytic reduction (SCR), exhaust gas recirculation (EGR), and fuel switching, into a single system. This holistic perspective emphasizes the synergistic benefits of combining these techniques, offering a more effective strategy for implementation in realworld settings. It addresses the practical challenges associated with these technologies, such as economic, logistical, and regulatory considerations, and proposes potential solutions. Thus, it bridges the gap between theoretical research and practical application, making its findings highly relevant to industry stakeholders. Alongside the review of existing technologies, the paper also proposes new ideas and integrated approaches that contribute to the scientific understanding and practical application of NOx reduction strategies in maritime transport, which is essential for promoting environmental sustainability in the industry. [ABSTRACT FROM AUTHOR]

Low-carbon fuels, feedstocks, and energy sources can play a vital role in the decarbonization of clinker production in cement manufacturing. Fuel switching with renewable natural gas, green hydrogen, and biomass can provide a low-carbon energy source for the high-temperature process heat during the pyroprocessing steps of clinker production. However, up to 60% of CO2 emissions from clinker production are attributable to process-related CO2 emissions, which will need the simultaneous implementation of other decarbonization technologies, such as carbon capture. To evaluate the potential of fuel switching and carbon capture technologies in decarbonizing the cement industry, a study of the facility-level CO2 emissions is necessary. This study evaluates the potential for using a single low-carbon fuel as an energy source in clinker production for cement manufacturing compared to conventional clinker production (which uses a range of fuel mixes). In addition, conventional carbon capture (operated with natural gas-based steam for solvent regeneration) and electrified carbon capture configurations were designed and assessed for net-zero emission targets. Carbon emissions reductions with and without biogenic emissions credits were analyzed to ascertain their impact on the overall carbon accounting. Results show that carbon emissions intensity of cement can vary from 571 to 784 kgCO2eq/metric ton of cement without carbon capture and from 166.33 to 438.66 kgCO2eq/metric ton of cement with carbon capture. We find that when biogenic carbon credits are considered, cement production with a sustainably grown biomass as fuel source coupled with conventional carbon capture can lead to a net-negative emission cement (−271 kgCO2eq/metric ton of cement), outperforming an electrified capture design (35 kgCO2eq/metric ton of cement). The carbon accounting for the Scope 1, 2, and biogenic emissions conducted in this study is aimed at helping researchers and industry partners in the cement and concrete sector make an informed decision on the choice of fuel and decarbonization strategy to adopt.

Mandatory use of low-sulfur fuel according to global sulfur limit regulation has reduced the emissions of SO2 and PM significantly on ships, while it also leads to very large uncertainty on VOCs emission. Therefore, on-board test of VOCs from 9 typical cargo ships with low-sulfur fuels in China were carried out in this study. Results showed that emission factor of VOCs (EFVOCs) varied largely from 0.09 to 3.01 g kg-1 fuel, with domestic coastal cargo ships (CCSs) had the highest levels and ocean-going vessels (OGVs) the lowest. The switch of fuels from heavy fuel oil (HFO) to diesel increased EFVOCs by 48 % on average, which enhanced both O3 and secondary organic aerosol (SOA) formation potentials, especially for OGVs. Besides, the use of low-sulfur fuels for OGVs also lead to significant increase of naphthalene emission. These indicated the implementation of globally ultra-low-sulfur oil policy in the near future needs to be optimized. Moreover, aromatics were the most important common contributors to O3 and SOA in ship exhausts, which need to be controlled with priority. It was also found that benzene, toluene, and ethylbenzene ratio of 0.5:0.3:0.2 on average could be considered as a diagnostic characteristic to distinguish ship emission from other emission sources. [ABSTRACT FROM AUTHOR]

The concerns over greenhouse gas emissions, environmental impacts, climate change, and sustainability continue to grow. As a result of countermeasures, many modern gas turbine power plants and combined cycle power plants are considering to use hydrogen as a clean fuel alternative to fossil fuels in the power plant industry. We assessed the implications of such transition from natural gas to hydrogen as fuel in a gas turbine power plant's balance of plant (BOP) equipment. Using the DWSIM process simulation software and the methodology of compression power changes against different gas compositions, the impact of blending hydrogen with natural gas on temperature differentials, energy consumption, adiabatic efficiency, compression power, and economic implications in gas turbine power plants were examined in this paper. We discovered, through analysis, that there was not a noticeable boost in compression power or energy consumption when 50% hydrogen and 50% natural gas were blended. Similarly, there was no discernible difference in temperature differentials or adiabatic efficiency when 30% hydrogen and 70% natural gas were blended. Moreover, mixing 50% hydrogen and 50% natural gas did not result in a noticeable cost climb. In addition, the techno-economic analysis presented in this paper offered valuable insights for power plant engineers, power generation companies, investors in energy sectors, and policymakers, highlighting the nature of the fuel shift and its implications on the economy and technology. [ABSTRACT FROM AUTHOR]

The article focuses on the vulnerability of energy systems to disruptions and highlights a common emphasis on supply-side policies for energy security, overlooking the potential of demand-side interventions. It authors propose a systematic approach that considers energy demand, concluding that demand-side actions are more effective than traditional supply-side approaches in enhancing a country's resilience to energy crises.

This paper presents an extension of industry modelling within the REMIND integrated assessment model to industry subsectors and a projection of future industry subsector activity and energy demand for different baseline scenarios for use with the REMIND model. The industry sector is the largest greenhouse-gas-emitting energy demand sector and is considered a mitigation bottleneck. At the same time, industry subsectors are heterogeneous and face distinct emission mitigation challenges. By extending the multi-region, general equilibrium integrated assessment model REMIND to an explicit representation of four industry subsectors (cement, chemicals, steel, and other industry production), along with subsector-specific carbon capture and sequestration (CCS), we are able to investigate industry emission mitigation strategies in the context of the entire energy–economy–climate system, covering mitigation options ranging from reduced demand for industrial goods, fuel switching, and electrification to endogenous energy efficiency increases and carbon capture. We also present the derivation of both activity and final energy demand trajectories for the industry subsectors for use with the REMIND model in baseline scenarios, based on short-term continuation of historic trends and long-term global convergence. The system allows for selective variation of specific subsector activity and final energy demand across scenarios and regions to create consistent scenarios for a wide range of socioeconomic drivers and scenario story lines, like the Shared Socioeconomic Pathways (SSPs). [ABSTRACT FROM AUTHOR]

Alternative fuels of low or zero carbon content can decarbonise the shipping operations. This study aims at assessing the lifetime environmental-economic sustainability of ammonia and hydrogen, as alternatives to diesel fuel for short sea shipping cargo vessels. A model is employed to calculate key performance indicators representing the lifetime financial sustainability and environmental footprint of the case ship using a realistic operating profile and considering several scenarios with different diesel substitution rates. Scenarios meeting the carbon emissions reduction targets set by the International Maritime Organisation (IMO) for 2030 are identified, whereas policy measures for their implementation including the emissions taxation are discussed. The derived results demonstrate that the future implementation of carbon emissions taxation in the ranges of 136–965 €/t for hydrogen and 356–2647 €/t for ammonia can support these fuels financial sustainability in shipping. This study provides insights for adopting zero-carbon fuels, and as such impacts the de-risking of shipping decarbonisation. [Display omitted] • Economic and environmental sustainability assessment of diesel fuel substitution. • Scenarios for addressing IMO decarbonisation targets with ammonia and hydrogen. • Hydrogen fuel prices below 700 €/t provide economic sustainability. • Carbon tax of 136 €/t for H 2 and 261 €/t for NH 3 is required to reach baseline NPV. • H 2 substitution scenarios over performs ammonia in economic sustainability. [ABSTRACT FROM AUTHOR]

In order to comply with the latest Emission Control Areas (ECAs) regulations, ships must use expensive low-sulphur fuel oil or relatively cheap high-sulphur fuel oil (HFO) with desulphurization equipment. This study investigates the choice of green fuel and green technology for a coastal container ship with endogenous decision of sailing pattern. The sufficient and necessary conditions for a ship to adopt scrubber installation (SI) strategy are derived, which is dependent on factors including the equivalent sailing distance, the fuel price ratio, and scrubber parameters. The case study based on the China's coastal area is conducted. Numerical examples show that the introduction of scrubber technology on coastal vessels will reduce their evasion behavior. However, the increased sulphur reduction efficiency of scrubbers increases the evasion strategies of ships, which will increase the total emissions in coastal areas. The numerical example shows that introduction the scrubber technology to the coastal ships will reduce their evasion behavior. However, the scrubber investment will increase ships' sailing speed, increasing emissions within ECA. Therefore, governments can subsidize high abatement efficiencies of the scrubber to reduce actual ship emissions. • Investigate the choice of technology for a coastal ship with endogenous decision of sailing pattern. • Study the properties of the optimal sailing speed under fuel switching and scrubber installation strategies. • Derive the sufficient and necessary condition for a coastal ship of adopting scrubber installation strategy. • Discuss the incentive of evasion behavior and effect on emissions within ECA.. [ABSTRACT FROM AUTHOR]

This study discusses the topic of thermal efficiency analysis in gas turbines. This study aims to determine the effect of using LNG and HSD fuel on the value of thermal efficiency. Therefore, the actual brayton cycle calculation method is used. This research is doing data processing using software, namely Microsoft Excel, Engineering Equation Solver (EES) and Cycle Tempo. Based on the results of the calculations that have been carried out, the thermal efficiency at a load of 75 MW with LNG fuel is 37.96% to 44.62% at a load of 100 MW and with HSD fuel at a load of 75 MW it is 40.61% and 45.60% at a load of 100 MW. Then in the EES simulation results with LNG fuel at a load of 75 MW it is obtained 37.51%, and 41.96% at a load of 100 MW. whereas with HSD fuel at a load of 75 MW it was obtained 41.76% and 46.15% at a load of 100 MW, and also the results of the cycle tempo simulation with LNG fuel at a load of 75 MW were 32.56% to 37.43% at a load 100MW. Then with HSD fuel at a load of 75 MW it is 34.47% to 38.14% at a load of 100 MW [ABSTRACT FROM AUTHOR]

This study explores emissions regulation of a 3.5 kW single cylinder, direct injection, diesel engine fuelled with biogas and Mahua biodiesel. By varying the compression ratio from 17 to 18 with a step of 0.5, pilot fuel injection timing by 3° BTDC from 23° BTDC to 32° BTDC, and engine load from 20% to 100% with a step of 20%, the optimal operating conditions are determined using response surface methodology. At the optimum engine operating parameter settings of a 17.73 compression ratio, 26.71° BTDC pilot fuel injection timing, and 58.96% engine load, the optimum emissions are 42.89 ppm for NOx, 80.36 ppm for UHC, 4.23% Vol. for CO 2 , and 77.72 ppm for CO. Additionally, the study demonstrates a comparable brake thermal efficiency of 17.35% with 66.26% pilot fuel substitution, indicating biogas-biodiesel as a sustainable and renewable option for dual-fuel CI compression-ignition engines. • Running biogas biodiesel has resulted in a significant decrement in NOx emissions. • Alteration in compression ratio and injection timing lowered CO and HC emissions. • Maximum optimum attained pilot fuel substitution is 66.26%. • Maximum brake thermal efficiency obtained is of 17.35%. • Optimization attained with best goodness of fit range of 0.86–0.99. [ABSTRACT FROM AUTHOR]

The concepts of residual gas and admission (or volumetric efficiency) coefficients are used exclusively by specialists in the field of piston Internal Combustion Engines. However, it is preferable to apply the concepts of volume fractions of components of the working mixture consisting of air, fuel, residual, and recirculating gases, for the evaluation of filling. This simplifies and makes it more easy-to-grasp the influence of individual factors on the results of gas exchange processes. The proposed approach makes it possible to take into account the impact on the engine indicators of the molecular weight of the fuel used and the degree of external recirculation, as well as to reduce the number of independent variables. At the same time, the displacement coefficient A proposed by the author characterizes a decrease in filling when an engine with external mixing is switched to a gaseous fuel with a lower molecular weight. A change in the valve timing made it possible to produce an effect on the composition of the working mixture and, thereby, the environmental characteristics of the engine. In the case of external recirculation, it becomes necessary to estimate the summary fraction of neutral combustion products in the working mixture, on which all engine operation depended. This ”overall degree of recirculation” can also be determined using the proposed approach. [ABSTRACT FROM AUTHOR]

This article deals with modeling sulfur dioxide (SO2) concentrations emitted by two industries in Santiago de Cali. These industries use different fuel types in their boilers: Boiler 1 uses Fuel Oil, and Boiler 2 uses Diesel. To evaluate and compare the behavior of SO2 concentrations, the substitution of these fuels by natural gas is proposed. Using Aermod View, this pollutant's dispersion was modeled and obtained that the maximum SO2 concentration from the boilers with Fuel Oil and Diesel was 1440.32 µg/m3 for an exposure time of one hour. For a 24-hour exposure time, the SO2 concentration reached 178.56 µg/m3. These levels exceed the limits established in resolution 2254 of 2017, where the maximum permissible value for one hour is 100 µg/m3, and for 24 hours is 50 µg/m3. In contrast, when using Natural Gas as fuel, it is observed that the concentrations are considerably lower. The maximum concentration is 0.74 µg/m3 for a one-hour exposure time, and for a 24-hour exposure time, 0.04 µg/m3. These results comply with current regulations. It can be concluded that natural gas is a more favorable alternative, generating significantly lower SO2 concentrations. This change in the fuel type will favor compliance with environmental regulations and effectively contribute to reducing SO2 concentration in the air. [ABSTRACT FROM AUTHOR]

Decoupling of production activities and greenhouse gas (GHG) emissions, or a decline in GHG intensity, is a key metric for gauging GHG mitigation performances. In this study, we explore the determinants of GHG intensity in Canadian industries to understand its key drivers. This study is relevant, because Canada is a developed country characterized by high energy and GHG intensities. Canada has also introduced a series of policy measures to mitigate GHG emissions, including a carbon tax and investments in renewable electricity. The most significant factor for GHG intensity is energy intensity. However, fuel mix, policy trends, and sectoral shifts are essential. After conducting stationarity and cointegration tests, we estimated the relationship between GHG intensity and these determinants using panel error correction, dynamic fixed effects, and dynamic OLS methods to determine the long-run relationships. Besides the strong effect of energy intensity, we found that industrial production mix that indicates sectoral shifts, fuel mix, and the time-fixed effects that capture factors such as the introduction of a carbon tax and technology standards have statistically significant impacts on GHG intensity. We found that industries that rely more on fuel sources other than electricity are characterized by higher GHG intensity. The policy implication is that energy efficiency and fuel switching are essential for reducing GHG intensity, but the role of factors such as sectoral shifts should not be ignored. [ABSTRACT FROM AUTHOR]

This study analyzed the particulates and gaseous emissions from 2005 to 2022 for power plants in South Korea (Utility scale: 125 MW (B-1) and 200 MW (B-2), respectively), which recently successfully converted from coal to wood pellets. The analysis showed that (1) NOx reduction was 78.9 to 90.0% (with outlet denitrification facility), (2) SOx reduction was 95.0 to 99.6% (without desulfurization facility condition), and (3) total suspended particles (TSP) reduction was 70.3 to 87.2% (with improved filtration and dust collection facility). This research confirmed the capabilities of wood pellets as a baseload power source and demonstrated their superior NOx reduction compared to coal. In the case of SOx, the desulfurization facility was discontinued at the stage of the fuel switch, so the value was affected by exogenous variable factors other than fuel. The TSP appears to be a combination of the ‘fine dust' contained in the wood pellets and the performance of the filtration dust collector. The results suggest that fuel switching to wood pellets is a viable alternative to fossil fuels as an appropriate climate technology.