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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]

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]

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]

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.

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 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]

Emissions of maritime transport have been a critical research topic with the substantial growth in the global shipping industry, encompassing both the expansion of the world fleet and the increased distances it has been covering recently. The International Maritime Organization (IMO) has enforced some regulations to mitigate ship Greenhouse Gas (GHG) emissions, which affect vessels' operational practice, and further affect service reliability. In this paper, some compliance methods (two-speed strategy, fuel switching, and LNG) against Emission Control Areas (ECAs) at the operational level are examined regarding if and how they impact the liner shipping schedule and service reliability; meanwhile, uncertain weather conditions and port times, as the main uncertain factors, are also involved. Then, a bi-objective fuzzy programming model is formulated and solved by the augmented ε -constraint approach, which generates a set of Pareto solutions by balancing the economic and environmental sustainability. Some findings can be concluded through the experimental results, including that, firstly, to meet uncertain weather conditions at sea requires strong robustness; secondly, ECA regulations can negatively affect the liner shipping service level; moreover, slow steaming is an immediate and effective measure to reduce GHG emissions; and, furthermore, ship routing choice could have a significant influence on ship emissions and service reliability. [ABSTRACT FROM AUTHOR]

As a push towards alternative and renewable resources for heat and power generation, biomass and thermally treated fuels from biomass may be viable options in the upcoming economic reality. This study the verified mass and energy balance of spruce woody biomass after low temperature pyrolysis between 250 and 550 °C. The results showed that low-temperature pyrolysis can yield high-grade biochar suitable for substitution of fossil fuels. Crucially, the net calorific value of biochar processed at 350 °C substantially exceeded that of brown coal. An economic analysis was carried out on the assumption of the current economic reality in the Czech Republic. It was shown that even if the price of the biochar slightly increased, it would still be beneficial to invest in torrefaction technology over paying carbon credits. [ABSTRACT FROM AUTHOR]

Public transport can play a central role in representing a viable and sustainable mobility solution, especially in urban areas. Average energy consumption and emissions per passenger are much lower than for private cars. At the same time, current buses often mostly rely on diesel, and there are different solutions that can contribute to public transport decarbonization. Biomethane is among the options to exploit local low-carbon resources to decrease the emissions of public transport in urban environments. This paper presents the analysis of a real case study considering real data on the fuel consumption and mileage of the existing bus fleet in the city of Turin, Italy, composed by diesel and natural gas buses. The aim of this study is to estimate the effect of different penetration levels of biomethane in substitution of the current fuels. The results show that the use of biomethane in urban buses could save to up to 71% of emissions compared to the current situation, and savings would increase to 75% when deploying biomethane and electric buses together. Average emissions per pkm could decrease from a current level of 85.5 gCO2/pkm to 21.3–63.4 gCO2/pkm depending on the penetration of biomethane and electric buses. The sensitivity analysis shows even higher savings when accounting for the future decrease of the electricity carbon intensity in Italy and for the additional benefits related to avoided emissions from manure disposal. The results of the analysis demonstrate the potential contribution of biomethane in decarbonizing urban buses, and the findings presented for this case study can be of use for policy makers and researchers that deal with a similar situation in other cities and countries. [ABSTRACT FROM AUTHOR]

The abundance and replenishment nature of solid biomass prompt fuel substitution for gasification and thermal power plants. However, many challenges are encountered while utilizing raw biomass, such as seasonality, strong hydrophilicity, low bulk and energy density, excess oxygen content, less compositional homogeneity, and poor grindability. It is, therefore, indispensable to augment the thermo-chemical properties of the solid biomass by performing suitable pretreatment. Among the various pretreatment techniques, non-oxidative torrefaction effectively upgrades solid biomass to coal-like fuel altering its physico-chemical properties. Therefore, in this work, torrefaction of rice husk and sugarcane bagasse have been performed in a fixed bed reactor by varying temperatures from 210–330 °C and residence time from 30–60 min under a non-oxidative environment. The experimental investigation illustrates a decrease in mass and energy yield of the biomass with a rise in temperature and residence time. Conversely, the higher heating value of rice husk and sugarcane bagasse has improved by 119.4% and 128.9%, respectively. The hydrogen-to-carbon (H/C) and oxygen-to-carbon (O/C) ratio of the torrefied biomass has reduced to enriched fuel variety as indicated by the van Krevelen plot. The decomposition and structural modifications were assessed using Fourier transform infrared spectroscopy, x-ray diffraction, and morphology analysis. Based on the experimental observations, it has been found that torrefaction of rice husk at 290 °C and 30 min and sugarcane bagasse at 270 °C and 30 min would generate enriched syngas using a dual fluidized bed gasification system. Furthermore, water gas shift reactions will be promoted to enhance the percentage of hydrogen in the gas mixture. [ABSTRACT FROM AUTHOR]

Maritime transport accounts for around 3% of global anthropogenic greenhouse gas (GHG) emissions (Well-to-Wake). These GHG emissions must be reduced by at least 50% in absolute values by 2050 to contribute to the ambitions of the Paris Agreement signed in 2015. Switching to zero-carbon fuels made from renewable sources (hydro, wind, or solar) is seen by many as the most promising option to deliver the desired GHG reductions. However, renewable energy is a scarce resource that gives a much larger GHG reduction spent within other sectors. This study explores how to reach the IMO 2050 GHG targets exclusively through energy efficiency measures. The results indicate that by combining wind-assisted ship propulsion (WASP) with a slender hull form, fuel consumption and GHG emissions can be reduced by 30-35%, at a negative abatement cost for speeds exceeding 8 knots. Where the cost saving increases with the speed because at higher speeds, the fuel accounts for a higher share of the total cost, which implies that the cost saving goes from zero at 8 knots, to 5% reduction at 11 knots average speed to 14% reduction of total cost with 15 knots average speed. In comparison, GHG reductions through zero-carbon fuels will increase transport costs by 50-200%. [ABSTRACT FROM AUTHOR]

Firefighters' or instructors' exposure to airborne chemicals during live-fire training may depend on fuels being burned, fuel orientation and participants' location within the structure. This study was designed to evaluate the impact of different control measures on exposure risk to combustion byproducts during fire dynamics training where fuel packages are mounted at or near the ceiling. These measures included substitution of training fuels (low density wood fiberboard, oriented strand board (OSB), pallets, particle board, plywood) and adoption of engineering controls such as changing the location of the instructor and students using the structure. Experiments were conducted for two different training durations: the typical six ventilation cycle (six-cycle) and a shorter three ventilation cycle (three-cycle) with a subset of training fuels. In Part A of this series, we characterized the fire dynamics within the structure, including the ability of each fuel to provide an environment that achieves the training objectives. Here, in Part B, airborne chemical concentrations are reported at the location where fire instructors would typically be operating. We hypothesized that utilizing a training fuel package with solid wood pallets would result in lower concentrations of airborne contaminants at the rear instructor location than wood-based sheet products containing additional resins and/or waxes. In the six-cycle experiments (at the rear instructor location), OSB-fueled fires produced the highest median concentrations of benzene and 1,3 butadiene, plywood-fueled fires produced the highest total polycyclic aromatic hydrocarbon (PAH) concentrations, particle board-fueled fires produced the highest methyl isocyanate concentrations, and pallet-fueled fires produced the highest hydrogen chloride concentrations. All fuels other than particle board produced similarly high levels of formaldehyde at the rear instructor location. The OSB fuel package created the most consistent fire dynamics over six-cycles, while fiberboard resulted in consistent fire dynamics only for the first three cycles. In the follow-on three-cycle experiment, PAH, benzene, and aldehyde concentrations were similar for the OSB and fiberboard-fueled fires. Air sampling did not identify any clear differences between training fires from burning solid wood pallets and those that incorporate wood-based sheet products for this commonly employed fuel arrangement with fuels mounted high in the compartment. However, it was found that exposure can be reduced by moving firefighters and instructors lower in the compartment and/or by moving the instructor in charge of ventilation from the rear of the structure (where highest concentrations were consistently measured) to an outside position. [ABSTRACT FROM AUTHOR]

Thailand's civil aviation industry has expanded rapidly in the past ten years resulting in increasing aviation greenhouse gas (GHG) emissions and energy consumption. The rapid growth in air transport is anticipated to continue further. Presently, domestic aviation and the economy of many countries are recovering rapidly in the post-COVID-19 period, resulting in fuel consumption and GHG emissions gradually increasing again. However, despite implementing the ICAO's CORSIA (International Civil Aviation Organization's Carbon Offsetting and Reduction Scheme for International Aviation) rule for international aviation, GHG emissions in the domestic aviation sector are largely unregulated. Moreover, the literature lacks a GHG emissions analysis that considers this sector's potential growth and mitigation policies for future GHG emissions. To close the gap, this study conducted a GHG emissions analysis from this sector under various scenarios through 2050 using historical data during 2008–2020 to forecast future trends. It evaluates the impact of the mitigation policies, such as fuel switching and aircraft technology, on improving fuel efficiency due to technological advancements in aircraft and carbon pricing. The results show that the fuel switching option would result in a significant long-term reduction in GHG emissions, whereas the carbon pricing option and aircraft technology option are desirable in reducing GHG emissions in the short term. Therefore, to meet GHG emissions reduction targets more successfully, all measures must be simultaneously executed to address short- and long-term mitigation strategies. These findings have significant implications for both present and future GHG emissions reduction measures, supporting Thailand's 2050 climate targets and energy efficiency policies as the domestic aviation industry adjusts. [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. [ABSTRACT FROM AUTHOR]

This study aims to derive bioenergy from waste lather fat and citronella grass. Lather fat oil (LFO), citronella grass oil (CGO), a mixture of leather fat oil and citronella grass oil (LFCGO), and a nano-additive-incorporated mixture of lather fat oil and citronella grass oil (NFCO) were synthesized and used in diesel engines as the novelty of this study. ASTM standards were used to investigate and guarantee the fuel's properties. According to the experimental report, the nanoadditive's brake thermal efficiency and brake-specific fuel consumption were more comparable to diesel fuel. Compared to diesel, the NFCO blend reduced hydrocarbon, carbon monoxide, and particulate emissions by 6.48%, 12.33%, and 16.66%, respectively, while carbon dioxide and oxides of nitrogen emissions increased. The experiment's outcomes were verified using an artificial neural network (ANN). The trained model exhibits a remarkable coefficient of determination of 98%, with high R values varying from 0.9075 to 0.9998 and low mean absolute percentage error values ranging from 0.97% to 4.24%. Based on the experimental findings and validation report, it can be concluded that NFCO is an efficient diesel fuel substitute. [Display omitted] • Identified substitute fuel from waste biomass for diesel engine. • Evaluated the engine output responses of waste biomass-based test fuel. • Identified the best fuel modification methods to eliminate the NOx. • Numerically validated the experimental results by ANN. [ABSTRACT FROM AUTHOR]

The requirements to reduce emissions of carbon dioxide and other greenhouse gases from maritime transport require taking actions aimed at increasing the overall efficiency of the propulsion system, optimal and rational use of electricity and heat. Taking such actions is necessary in order to demonstrate the improvement of the energy efficiency index of a ship in operation or an already existing one (EEOI and EEXI), which will allow to obtain category A or B emissions for a given ship. Obtaining similar energy efficiency effects is also possible after switching to fuels containing less carbon in the molecule and the use of renewable energy. Attempts are made to create new configurations of combined energy systems so as to obtain maximum benefits related to the use of various energy sources in order to ensure the production of energy in quantities consistent with the current demand of the ship in the operating condition. [ABSTRACT FROM AUTHOR]

The use of hydrogen can be a potential solution to reduce high CO and unburnt HC emissions, which is one of the most critical challenges, from Reactivity Controlled Compression Ignition (RCCI) engines at low loads as it is a very clean and carbon-free fuel candidate for internal combustion engines. Therefore, the aim of this study is designed to investigate numerically the effect of the hydrogen share on combustion characteristics in a diesel research engine operated in RCCI mode. The engine is fueled with conventional diesel and iso-octane enriched with hydrogen and is operated at 20% of the maximum torque (low load) and 2400 rpm. A 40% of conventional diesel (in the case of conventional diesel mode (CDM), its share was 100%) is injected per cycle into cylinder of the engine, while varying proportions of iso-octane (60% to 12%) and hydrogen (0% to 48%) are sprayed into the air from the intake manifold. Both CDM and RCCI combustion models built by 3D scanning of the existing engine using reverse engineering to computational fluid dynamic (CFD) was simulated through ANSYS-Forte coupled with a chemical kinetics solver (Chemkin-Pro). The simulation results showed that by adding hydrogen to iso-octane in RCCI mode, the proportion of hydrogen could be increased up to 48% while improving thermal efficiency by 33.3% in comparison with 24.9% with RCCI without hydrogen addition. Therefore, the overall hydrocarbon fuel consumption per cycle was reduced by up to 47.52%. Hydrogen addition resulted in a higher concentration of OH species in the flame front, and higher pressure and temperature in the cylinder, in turn, contributed to an increase in NOx emissions considerably but led to decrease in CO/HC emissions of RCCI operation. The decrease in the emissions of CO, HC, and C2H2 of up to 64.6, 81.8, and 76.6%, respectively, was observed by using 48% of H2 in RCCI mode compared to RCCI mode without hydrogen addition. It was concluded that high CO and unburned HC emissions from RCCI combustion. This research provides promising contributions to the literature for using hydrogen in substitution of hydrocarbon fuels and reducing emissions from RCCI engines. [ABSTRACT FROM AUTHOR]

This paper presents the extension of industry modelling within the REMIND integrated assessment model to industry subsectors, and the 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 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 energyeconomy- climate system, covering mitigation options ranging from reduced demand for industrial goods, over 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 the use with the REMIND model in baseline scenarios, based on short-term the 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]

The urge for cleaner and greener sources of energy is rising day by day. Developed countries are already in process of shifting their energy needs from conventional sources to non-conventional/renewable/green sources of energy. These developed countries are also trying to incorporate developing countries to join the battle against global warming and pollution. Examples, of some non-conventional sources of energy are nuclear energy, wind energy etc. One of such cleaner energy source is hydrogen. The high calorific value, availability in abundance and cleaner nature of hydrogen makes it an appropriate substitute for conventional source of energy. An engine using gaseous hydrogen is in the process of being developed. This may revolutionize the battle against pollution and global warming. Use of hydrogen in a diesel engine working on dual-fuel mode has been the interest of many researchers. However utilization of hydrogen fuel changes the ignition delay, combustion duration, peak mean temperature, peak pressure and other combustion parameters change. In the present work, such research works are examined and analyzed in detail. It is also shown, amount of inducted hydrogen dictates many engine parameters such as engine power, torque etc. a separate section is dedicated to study different emissions from the improvised engine. Lastly, it will be clear from the discussion that introduction of gaseous hydrogen to a diesel engine working on dual fuel mode will have optimistic effect on environment. [Display omitted] • The high calorific value, availability in abundance and cleaner nature of H 2. • An engine using gaseous hydrogen is in the process of being developed. • Use of gaseous H 2 to a diesel engine will have optimistic effect on environment. • Combustion parameters like ID, CD and mean temperature of gas increases. • NOx increases with substitution of hydrogen fuel. [ABSTRACT FROM AUTHOR]

The substitution of fossil fuels with renewable energy sources such as hydrogen is a decisive factor in making aviation environmentally compatible. A key parameter for the use of hydrogen is the storage system. In the design of a flight-capable storage system, not only the mass but especially the volume of the hydrogen has to be considered. Therefore, in this paper different techniques are compared and evaluated from the point of view of their application in aircraft design. The analyses are performed on two reference aircraft, the Airbus A320 and the Embraer E 190, in the short- and medium-haul range. Simplified, it is assumed that the respective max. Take-off mass (MTOM) remains constant. The change of the necessary periphery has no influence on the MTOM. A tank concept could be designed, which can find applications in today's conventional aircraft design. • Energy consumption calculated for A320 and E 190. • Flight data evaluation. • Comparison of different storage methods. • Calculation of volumes for different storage methods and ambient pressures. • Discussion about possible constructive misplacement. [ABSTRACT FROM AUTHOR]

Nigeria has the potential to generate 12,522 MW of electricity, but can only dispatch 4000 MW, which is insufficient for a population of over 200 million people as of 2022. Therefore, Nigerians use solid fuels including firewood and charcoal as an alternative to insufficient electricity for domestic use. The consumption of firewood and charcoal in Nigeria is estimated at 23,745,458 tons and 4,828,689 tons, respectively in 2021, by far the most consumed domestic solid fuel sources in Nigeria. Although there are domestic solid fuel alternatives, such as dung, agricultural residues and coal, to firewood and wood charcoal, their sustainable adoption has been slow in Nigeria, indicating that there is insufficient knowledge of domestic solid fuel sources. This requires a review focused on assessing Nigeria's national sources of solid fuels. This article presents an overview of the sources of domestic solid fuels in Nigeria, an exploration of different types of firewood and charcoal studies, the impact of solid fuels on climate change and the environment, health risks associated with solid fuel and biomass briquettes and pellets as domestic solid fuel alternatives to charcoal and firewood. The continued production and use of firewood and wood charcoal as domestic solid fuel sources encourage deforestation, desertification and greenhouse gas emission, which in turn pose a threat to a sustainable environment and good health. It is necessary to limit the felling of trees for firewood and charcoal production to curtail their negative impacts on the health of users and the environment. This review covered the thermal, mechanical and physical properties of briquette and pellet fuels as substitutions for firewood and charcoal. It was shown that employing briquettes and pellets as a source of solid fuel in the home will lessen the negative impacts that these fuels have on users' health, the climate and the environment. [ABSTRACT FROM AUTHOR]

The conventional energy source in cement industries is fossil fuels, mainly coal, which has a high environmental footprint. On average, energy expenditures account for 40% of the overall production costs per ton of cement. Reducing both the environmental impact and economic expenditure involves incorporating alternative energy sources (fuels) such as biomass, solid-derived fuel (SDF), refuse-derived fuel (RDF) etc. However, within cement plants, the substitution of conventional fossil fuels with alternative fuels poses several challenges due to the difficulty in incorporating additional fuel-saving techniques. Typically, an additional 3000 MJ of electricity per ton of clinker is required. One of the most effective solutions to this is thermal optimization through co-processing and pre-processing, which makes it possible to implement additional fossil-fuel-saving techniques. In developing nations such as Togo, waste-management systems rely on co-processing in cement factories through a waste-to-energy relationship. Also, there are some old cement plants with low-efficiency, multi-stage preheaters without pre-calciners, reciprocating huge coolers, low-efficiency motors etc., which still operate and need to be made environmentally sustainable. However, compared to modern kilns which can have up to 95% of energy recovery from waste, an old suspension preheater kiln can recover only up to 60% of its heat energy depending on the cooler type, and due to the lack of a bypass and combustion chamber (pre-calciner). This research paper evaluated the performance of a cement plant incorporating AF and presents the procedures and recommendations to optimize AF substitution in cement plants. To achieve this, a comparative performance study was carried out by assessing the alternative fuel characteristics and the equipment performance before and after the incorporation of the alternative fuel. Data were collected on the optimum substitution ratio, pre-processing and co-processing performance, raw-meal design and economic analysis. Results indicated that the cost to be covered per ton of waste input is €10.9 for solid-derived fuel (SDF), €15 for refuse-derived fuel (RDF), and that the co-processing cost optimization for the cement plant could have a cost saving of up to 7.81€/GJ. In conclusion, it is recommended that appropriate kiln and alternative-fuel models be created for forecasting production based on various AF. [ABSTRACT FROM AUTHOR]

Trucks has caused serious atmospheric pollutant and greenhouse gas emissions in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA), China, while substituting the truck fuel (gasoline/diesel) by green hydrogen is a critical way to solve the problems. Accordingly, we established a Hydrogen availability-Greenhouse gas and Atmospheric Pollutant emission reduction (HGAP) evaluation model. We revealed that the annual available green hydrogen energy in the GBA reached 1.36 × 1010 GJ, which could fuel all the trucks in the region. Via truck fuel substitution by hydrogen, a 45% reduction in regional greenhouse gas emissions in the GBA could achieve. The emission reductions of CO and HC by vehicles in the GBA achieved approximately 1/4, NOx was about 1/2 and PM was about 60%. We served a solution of developing without eco-sacrifice for developed, strategic yet high-emission coastal regions and countries. • A solution of developing without eco-sacrifice for strategic yet high-emission China GBA. • The H 2 availability in the China GBA is 1.36 × 1010 GJ/a able to fuel all trucks in the region. • A 45% reduction in regional greenhouse gas emissions in the China GBA. • Up to 60% emission reductions of atmospheric pollutants by vehicles in the China GBA. [ABSTRACT FROM AUTHOR]

With the increasing sludge production and cement carbon emissions worldwide, there is an urgent need to develop synergistic approaches to sludge co-process in cement kilns options for building up an interactive sludge carbon reduction process. Cement kilns with temperatures as high as 1450 °C can dissipate various wastes and completely decompose or solidify harmful substances, including dioxins and heavy metals, in the cement crystal structure. Therefore, cooperative cement kiln disposal of sludge can thoroughly decompose organic components as well as their intrinsically cured heavy metals. The vast majority of cement production lines in the world are already equipped for co-process, but the disposal of sludge is blended at a relatively small amount of about 6%. This paper first summarizes the physicochemical characteristics of different types of sludge. In addition, the discussion focuses on the sludge raw material substitution principle and the heavy metal solidification process. The mechanism of K+, Na+, and Cl- plasma damage is further investigated in depth. The overview study predicts the annual carbon emission reduction content of about 25 million tons from two routes of cement kiln co-process of sludge and other solid wastes such as raw material substitution and alternative fuels and cross industries. [Display omitted] • The feasibility of cement kiln co-processing of sludge was critically discussed. • The solidification mechanism of heavy metals in cement production was analyzed. • The mechanism of harmful ions to cement kilns was revealed. [ABSTRACT FROM AUTHOR]

This work utilized the conventional transesterification process to convert waste pork fat into pork fat biodiesel. The produced biodiesel was meant to serve as a diesel fuel substitution for common rail direct injection (CRDI) diesel engines. Butylated Hydroxytoluene (BHT) as an antioxidant doping with waste pork fat biodiesel-diesel blend has not been analyzed in CRDI diesel engines. Therefore, to improve the ignition process and reduce the engine exhaust emissions in a research CRDI diesel engine, the BHT was employed to combine with diesel-biodiesel mixtures in this work. BHT antioxidants are partially mixed (BHT 50, 100, and 150 ppm) to improve the physicochemical qualities of test fuel and enhance the combustion process of diesel-biodiesel blends (B20). The antioxidant purity was analyzed by energy dispersive X-ray analysis (EDX), structures were analyzed by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) analyzer spectrograph was utilized to study the biodiesel chemical components. After mixing the BHT, the overall phase of the base fuel remained constant. The experiment outcomes revealed that the biodiesel had higher cylinder pressure than the other test fuels, and the BHT100 ppm blend had a higher heat release rate (HRR). B20BHT100 blend shows 3.98% higher brake thermal efficiency (BTE) at full load operation than pure biodiesel but lowered to diesel fuel. Biodiesel (B100) decreases the smoke opacity by 4.5% compared to diesel fuel. BHT has been incorporated into the biodiesel blend to minimize oxides of nitrogen (NOx) emissions at all loads. The B20BHT150 blend decreased NOx emissions by 5.06% more than diesel fuel at maximum load. Compared to pure biodiesel, the B20 blends reduce carbon monoxide (CO) emissions by 7.1% and hydrocarbon emission (HC) by 12.5%. This research found that adding BHT to biodiesel blends lowers NOx emissions with a slight impact on performance. [Display omitted] [ABSTRACT FROM AUTHOR]

Nanostructures present favorable prospects of manufacturing high-performing air electrodes for reversible solid oxide fuel cells (RSOFCs) with the potential to reduce their operating temperature. Here, we present trichloroacetic acid as an original infiltration agent for the facile nanoengineering of RSOFC electrodes. The new process relies on the thermal decomposition of trichloroacetic acid in water at temperatures above 70 °C, which causes intense CO 2 effervescence and crystallizes out the metal ions in the solution as slightly soluble carbonates. Essentially, this allows for the subsequent infiltration step to be performed immediately after drying, as opposed to conventional infiltration, which requires high-temperature calcination after each infiltration step. The anode-supported RSOFC consisting of a nanostructured LaCoO 3 air electrode permitted smooth switching between fuel cell and electrolysis cell modes with no evidence of degradation. In addition, the RSOFC presented exceedingly durable performance during accelerated stability tests. [Display omitted] • Trichloroacetic acid is introduced as a novelty nanoengineering substance for use in SOCs. • A LaCoO 3 3D-webbed nanostructured air electrode is successfully synthesized. • Excellent performance is achieved in fuel cell and electrolysis mode operations. • No degradation is observed during reversible and current load cycling operations. • Robust performance is reported for 300 h galvanostatic operation at 750 °C. [ABSTRACT FROM AUTHOR]

Vehicle use is associated with negative externalities such as traffic congestion, air pollution, and greenhouse gas emissions. Particularly in the U.S. as a car-oriented country, vehicle use — in terms of vehicle-miles of travel (VMT) — has been on the rise and is projected to increase in the future. To curb the VMT growth and mitigate the associated externalities, policy makers can design informed strategies based on VMT predicted by vehicle use models. However, traditional vehicle use models capture merely the observed heterogeneity across vehicle decision making units (e.g., individuals) and ignore the latent or taste heterogeneity sourced in individuals' attitudes and lifestyle preferences, which may cause biased and inconsistent results that mislead implications for policy makers. To address this research gap, the present study introduces a latent class regression model, where a probabilistic multinomial logit component endogenously classifies a sample of vehicle use observations so as to be homogeneous within and heterogeneous across the classes with respect to VMT. At the same time, a finite set of linear regression equations in the number of the latent classes yields class-specific VMT. The model is estimated on a sample dataset from the State of California identifying three latent classes, verifying the hypothesis of positing vehicle use on both observed and unobserved heterogeneity. The estimation results are analyzed to infer implications of potential policies aiming at reducing VMT through increasing fuel cost and switching to telework, and to evaluate the efficiency of resource allocation to policies by targeting different classes with distinctive characteristics. • Presents a latent class regression model of vehicle use in terms of VMT. • Empirically analyzes the model on a sample data from the State of California. • Identifies 3 classes with heterogeneous characteristics and preferences profiles. • Suggests policies to reduce VMT through higher fuel cost and switching to telework. • Evaluates efficiency of policies targeting classes with distinctive characteristics. [ABSTRACT FROM AUTHOR]

Dual fuel combustion leverages a high-reactivity fuel (HRF) to ignite a premixed low reactivity fuel (LRF)–air mixture to achieve high efficiencies and low engine-out emissions. The difference in the relative amounts of these fuels and in-cylinder fuel reactivity stratification profoundly impacts dual fuel combustion. The effect of increasing LRF energy substitution on dual fuel combustion at various fixed HRF (diesel) quantities was experimentally studied for two different LRFs (natural gas and propane) on a heavy-duty single cylinder engine at a constant intake pressure of 1.5 bar and injection pressure of 500 bar. Further, this effect was studied for three different HRF start of injection (SOI) timings of 310 CAD (50° BTDC), 330 CAD (30° BTDC), and 350 CAD (10° BTDC). For 310 CAD SOI, increasing the LRF substitution at a fixed HRF resulted in higher loads, peak cylinder pressures, and peak apparent heat release rates (AHRR). The onset of low temperature heat release (LTHR) was advanced as the LR fuel flowrate increased at a given pilot quantity for diesel–NG but remained constant for diesel–propane dual fuel combustion at these SOIs due to the impact of propane on the temperature at which the onset of LTHR occurs. The indicated fuel conversion efficiency (IFCE) ranged from 35% at 4 bar IMEPg to 47% at 9 bar IMEPg with NG as the LRF and from 35% at 3 bar IMEPg to 51% at 8 bar IMEPg with propane as the LRF. For 330 CAD SOI, the HC and CO emissions decreased at a higher fixed HRF quantity and an increasing LRF substitution. However, this was accompanied by significantly higher oxides of nitrogen (NOx) emissions for both NG and propane as LRFs. For 350 CAD SOI, increasing the LRF substitution at constant HRF consistently led to a higher second stage AHRR, whereas the first stage AHRR remained relatively unchanged for both NG and propane as LRFs. This was accompanied by higher IFCE for all fixed HRF quantities as LRF substitution was increased. For all SOIs studied, the HC and CO emissions were substantially lower and combustion stability was significantly improved as the LRF substitution (and consequently, the load) was increased. To the best of the authors' knowledge, the present work is unique in that it involves the first systematic experimental study of the impact of LRF energy substitution at fixed HRF quantities over a range of SOIs, providing comparative results for two different LRFs (NG and propane) on the same engine platform. [ABSTRACT FROM AUTHOR]

The deployment of CO2 capture and storage (CCS) and negative emissions technologies (NETs) are crucial to meeting the net-zero emissions target by the year 2050, as emphasised by the Glasgow Climate Pact. Over the years, several energy planning models have been developed to address the temporal aspects of carbon management. However, limited works have incorporated CCS and NETs for bottom-up energy planning at the individual plant scale, which is considered in this work. The novel formulation is implemented in an open-source energy system software that has been developed in this work for optimal decarbonisation planning. The DECarbonation Options Optimisation (DECO2) software considers multiperiod energy planning with a superstructural model and was developed in Python with an integrated user interface in Microsoft Excel. The software application is demonstrated with two scenarios that differ in terms of the availabilities of mitigation technologies. For the more conservative Scenario 1, in which CCS is only available in later years, and other NETs are assumed not to be available, all coal plants were replaced with biomass. Meanwhile, only 38% of natural gas plants are CCS retrofitted. The remaining natural gas plants are replaced with biogas. For the more aggressive Scenario 2, which includes all mitigation technologies, once again, all coal plants undergo fuel substitution. However, close to half of the natural gas plants are CCS retrofitted. The results demonstrated the potential of fuel substitutions for low-carbon alternatives in existing coal and natural gas power plants. Additionally, once NETs are mature and are available for commercial deployment, their deployment is crucial in aiding CO2 removal in minimal investment costs scenarios. However, the results indicate that the deployment of energy-producing NETs (EP-NETs), e.g., biochar and biomass with CCS, are far more beneficial in CO2 removal versus energy-consuming NETs (EC-NETs), e.g., enhanced weathering. The newly developed open-source software demonstrates the importance of determining the optimal deployment of mitigation technologies in meeting climate change targets for each period, as well as driving the achievement of net-zero emissions by mid-century. [ABSTRACT FROM AUTHOR]

Despite the increasing need for chemicals and energy, the scenario in which fossil feedstocks can be completely replaced by renewables is currently unrealistic. Thus, the combination of biomass and non-renewable matrix-based (i.e., coal) technologies could provide a greener way toward the partial substitution of traditional fuels. The hydrogasification of carbonaceous feedstocks (coal and biomass) for the main production of CH4 offers a promising alternative to this end. However, hydrogasification has received very little attention, and the present review seeks to shed light on the process, reactor, and catalytic advances in the field. Independent of the selected matrices, various efforts have been devoted to the identification of efficient methods for the production of hydrogen feed to the gasifier and energy as well as the reduction in pollutant emissions from the plants. Moreover, the reactor configurations proposed are focused on the intensification of gas-solid contact to reduce by-product formation. The co-hydrogasification of both renewable and non-renewable feedstock is also reviewed, paying attention to the synergistic effect between the two matrices. In addition, due to the slow rates of hydrogasification reaction, the key role of catalysts and feedstock impurities on the reaction kinetics is discussed. [ABSTRACT FROM AUTHOR]

The current manuscript presents a review on existing kiln burner technologies for the cement production process, in the context of the current climate of energy transition and environmental remediation. Environmental legislation has become ever stricter in response to global climate change, and cement plants need to adapt to this new reality in order to remain competitive in the market and ensure their longevity. The cement production process is a well-established technology with more than a century of existence. There are several plants in operation whose process is outdated by modern standards, particularly considering the current industry decarbonization needs. The cement process requires tremendous amounts of energy, mainly recovered from the combustion of solid, liquid or gaseous fuels, which yields massive emissions of greenhouse gases. Thus, an important onus is placed upon the minimization of pollutant emission in the combustion system, as well as a substitution of fossil fuels with more sustainable alternatives. One of the sustainable alternative fuels comes in the form of refuse derived fuels (RDF). These high caloric fractions of municipal solid waste present a double advantage by reducing the amount of fossil fuels used and reducing the landfilling fraction of waste. However, their use in rotary kiln burners comes with important limitations for burner operation, namely that a high degree of control over primary air supply is needed to ensure complete combustion with minimal pollutant emission. [ABSTRACT FROM AUTHOR]

This research demonstrates a palm kernel shell gasification system for producing fuel gas, also known as producer gas. Using air as an oxidant, the gasification process converts palm kernel shells into fuel gas which contains combustible gases, such as hydrogen, carbon monoxide, and methane with nitrogen dominating the composition of the gas. This fuel gas can supply heat via direct combustion or generate electricity for fossil fuel substitution of an internal combustion engine. As a biomass-derived gas, the fuel gas is characterized as carbon-neutral inherently. During the conversion process, the system needs electricity to power the screw feeder, air blowers, and cooling-water pumps, and to rotate the gasifier's bottom plate to take the char out. Based on the experiments, mass balance, and energy balance calculations, this study examines the global warming, acidification, and eutrophication potential using the openLCA v1.10.3 software and Environmental Footprint (MID-Point indicator) database for impacts assessment when the system is operated in Indonesia and Malaysia with various electricity sources. It is found that the feedstock contributed most of the global warming potential and eutrophication potential, while the electricity dominated the acidification potential. This study recommends operation at a lower equivalent ratio to reduce environmental impacts. • Air gasification of palm kernel shells to produce fuel gas was conducted at a 25 kg/h gasifier capacity. • This study assessed the Global Warming, Eutrophication, and Acidification Potentials of the gasification process. • The effects of equivalent ratios on the environmental impacts were evaluated using a life cycle approach. • Palm kernel shells acquisition showed significant environmental impacts. • The scenarios to improve the process included variations of feedstock sources and electricity generation methods. [ABSTRACT FROM AUTHOR]

Sub-Sahara Africa is renowned for poor electricity supply with Nigeria's case being critical. Generator sets, which have been adopted as an alternative and reliable source of power in Nigeria, are linked to emission footprints detrimental to the environment and human health. The dearth of literature in open domain on the concentrations of pollutants and potential health risk related to the use of gasoline-fueled generators prompted this study. Concentrations of CO2, CO and particulate matter (PM2.5) emitted from selected randomly 174 gasoline-powered household generators were measured. Standard instruments were employed to measure these concentrations at 0.3–0.5 m from the exhaust pipe for 1 h (at 10 mins interval). The study area was Sango, Ogun State, Nigeria. The obtained results were 710 ± 19.1 ppm, 83 ± 4.0 ppm and 83 ± 4.1 µg/m3 (average) for CO2, CO, and PM2.5, respectively. The regression analyse carried out on the data for the age and efficiency of the generators in relation to the concentration data of CO2, CO and PM2.5 showed that the efficiency (R = 0.92 and F = 301.3) has more impact on the concentrations than the age (R = 0.68 and F = 49.6). Also, the efficiency of the generators was observed to have positive and significant effect on both the CO2 (t-stat = 10.05 and P-value = ≪ 0.050) and PM2.5 (t-stat = 2.26 and P-value = 0.025) concentrations. The average concentrations of CO2 and PM2.5 were observed to be higher than those recommended by the World Health Organization. Health impact assessment revealed hazardous and unhealthy status for CO and PM2.5 with air quality indices of >500 and 178.8, respectively. This study recommends efficient use of generators, fuel switching (gasoline to LPG), stringent emission measures and use of renewable energy as possible solutions. [ABSTRACT FROM AUTHOR]

Steel production is one of the biggest emitters of greenhouse gas in the industrial sector with about 8% of total global CO 2 emissions. Although the majority of emissions can be attributed to primary steel production, there is also potential for reducing CO 2 emissions in downstream steel processing. Large industrial furnaces, which are necessary for heating steel, are currently primarily fired with natural gas and by-product gases from primary steel production, offering great potential for heat recovery measures from exhaust gases. However, switching to alternative climate-neutral fuels could change this potential and thus jeopardize the economic viability of heat recovery measures. In the present work, it was therefore examined to what extent a change in energy sources in industrial furnaces affects the potential use of heat recovery in steel processing. For this purpose, an optimization model was used that takes into account heat recovery by means of direct heat transfer, heat pumps and heat distribution systems. Potential future changes in energy supply for industrial furnaces were examined using different storylines. Two different energy price scenarios were also considered to address uncertain developments in energy markets. The results show that heat recovery is a cost-effective and definitely recommendable measure. Switching to alternative fuels has little impact on the use of heat recovery. Electrification and thus the elimination of flue gas, on the other hand, greatly reduces the potential for heat recovery. [ABSTRACT FROM AUTHOR]

Global gas markets are changing as natural gas (NG) is replaced by biomethane. Biomethane is produced by upgrading biogas, which can have a molar concentration of methane to over 98%. This renewable energy has been injected into the pipeline networks of NG, which offers the possibility to increase its usage in industrial and residential applications. However, the expectation of the increase in biomethane proportion on the NG grids could increase the fluctuations on the composition of the NG–biomethane mixture in amplitude and frequency. In this context, the injection of biomethane into the existing network of NG raises a discussion about the extent to which variations in gas quality will occur and what permissible limits should exist, as variations in combustion characteristics can affect the operation of the combustion processes, with consequences for consumers, distributors and gas producers. This study describes a gas quality analysis with regard to the use of biomethane in industrial equipment, mixed or not mixed with NG, taking into account the indicators for gas interchangeability and provides a discussion on the necessary gas quality level to be achieved or maintained for efficient combustion in equipment originally designed to operate with NG. NG and biomethane real data collected for 92 consecutive days in 2022 and provided by two different companies in Brazil were used for this study. It is shown that the maximum deviation of the Wobbe Index (WI) of 5%, which is allowed for industrial plants, does not work for the operation of furnaces at temperatures of 1200 °C or more. In addition, it is shown that the WI, as defined in relation to the calorific value of the fuel, may allow inappropriate substitution of fuel gases, which is likely to reduce the range of blending of biomethane in NG pipelines. The results can be assessed to analyze how the addition of biomethane to NG grids will impact the WI and the equipment operation parameters such as the air-to-gas ratio, products-to-gas ratio, adiabatic flame temperature and furnace temperature. [ABSTRACT FROM AUTHOR]

The pulp and paper industry (PPI) has several opportunities to contribute to meeting prevailing climate targets. It can cut its own CO2 emissions, which currently account for 2% of global industrial fossil CO2 emissions, and it has an opportunity to produce renewable energy, fuels, and materials for other sectors. The purpose of this study is to improve understanding of the decarbonization prospects of the PPI. The study provides insights on the magnitude of needed annual renewal rates for several possible net-zero target years of industrial fossil CO2 emissions in the PPI and discusses decarbonization opportunities, namely, energy and material efficiency improvement, fuel switching, electrification, renewable energy production, carbon capture, and new products. The effects of climate policies on the decarbonization opportunities are critically evaluated to provide an overview of the current and future business environment of the European PPI. The focus is on Europe, but other regions are analyzed briefly to widen the view. The analysis shows that there are no major technical barriers to the fossil-free operation of the PPI, but the sector renovates slowly, and many new opportunities are not implemented on a large scale due to immature technology, poor economic feasibility, or unclear political environment. [ABSTRACT FROM AUTHOR]

To address climate change, power plants need to switch to greener fuels. One possible fuel is biomass; a carbon neutral/low carbon fuel. However biomasses' chemistries are both different from coal's and vary depending on their sources, containing unique levels of the trace elements (e.g., Cl and S) capable of altering the degradation of heat-exchangers. As such, an understanding of the effects of these variations on fireside corrosion is needed. Laboratory testing exposed alloys T91 and TP347HFG in a simulated agricultural product combustion environment at 600°C (up to 1000h; 100h cycles). Three different deposits mixtures were investigated (comprised of KCl, K2SO4, Na2SO4, CaSO4 indifferent percentages) mimicking accelerated corrosion from different biomasses. Corrosion behaviour was found to be dependant on both alloy and deposit chemistries, with the two materials showing different responses. The deposit with lowest KCl showed lowest corrosion damage, while the highest KCl deposit showed more aggressive behaviour. [ABSTRACT FROM AUTHOR]

Renewable sources play a crucial role in the decarbonisation process of the current linear economy, aimed at reaching the 2030 climate objectives and fulfilling the EU's long-term strategy of achieving carbon neutrality by 2050. All economic subjects, including households, can contribute to the Green Deal goals. The main goal of this paper is to evaluate households' consumption of energy sources for heating purposes in the Czech Republic in the period 2003–2020 and depict possible drivers of switching to biomass. For this, various data were collected, such as data published by the Czech Statistical Office, ministries, and other national authorities, as well as data from Eurostat. Concerning methods, data analysis, correlation analysis, and regression analysis were used. Different models focus on the substitution effect, rebound effect, and behaviour of different kinds of households. The results show a substitution effect connected with the consumption of coal, electricity, and biomass for heating purposes. Many households substituted coal for biomass in the observed period. On the other hand, the environmental impact of such substitution is not significant, as carbon emissions and emissions of other pollutants are stable. The substitution of fuels should be accompanied by technological change, e.g., improvement of combustion boilers. Moreover, households of pensioners are the key economic subjects with the highest impact on biomass consumption for heating purposes. Against this background we recommend policies to support households in replacing their boilers for more environmentally friendly ones. [ABSTRACT FROM AUTHOR]

We report here the development of a rotating molecular switch based on metal‐catalyzed reversible (de)‐hydrogenation. Under an argon atmosphere, acceptorless dehydrogenation induces a switch from an alcohol to a ketone, while reversing to a hydrogen pressure switches back the system to the alcohol. Based on a tolane scaffold, such reversible (de)‐hydrogenation enables 180° rotation. The absence of waste accumulation in a switch relying on chemical stimuli is of great significance and could potentially be applied to the design of efficient complex molecular machines. [ABSTRACT FROM AUTHOR]