Search Results (31)

This study combines convolutional neural network (CNN) recognition technology, Greenwich engineering software, and statistical yearbook methods to evaluate rural solar, wind, and biomass energy resources in pilot cities in China, respectively. The CNN method enables the rapid identification of the available roof area, and Greenwich software provides wind resource simulation with local terrain adaptability. The results show that the capacity of photovoltaic power generation reaches approximately 15.63 GW, the potential of wind power is 458.3 MW, and the equivalent of agricultural waste is 433,900 tons of standard coal. The city is rich in wind, solar, and biomass resources. By optimizing the hybrid power generation system through genetic algorithms, wind energy, solar energy, biomass energy, and coal power are combined to balance the annual electricity demand in rural areas. The energy trends under different demand growth rates were predicted through the LEAP model, revealing that in the clean coal scenario of carbon capture (WSBC-CCS), clean coal power and renewable energy will dominate by 2030. Carbon dioxide emissions will peak in 2024 and return to the 2020 level between 2028 and 2029. Under the scenario of pure renewable energy (H_WSB), SO₂/NO_x will be reduced by 23–25%, and carbon dioxide emissions will approach zero. This study evaluates the renewable energy potential, power system capacity optimization, and carbon emission characteristics of pilot cities at a macro scale. Future work should further analyze the impact mechanisms of data sensitivity on these assessment results. Full article

The activity of the present work is part of a research project aimed at proposing a solution for off-grid charging stations relying on the adoption of a reciprocating engine fuelled with alternative renewable fuels. This technology has as its main advantage the zero-carbon emissions impact of biofuels with small modifications to current ICE technology and refuelling infrastructure. This research is founded on preliminary experimental tests carried out on a six-cylinder spark-ignition engine adapted to pure ethanol fuelling with a single-point injection system. The experimental results obtained at different engine loads have been useful to build and validate a CFD model by testing several kinetic mechanisms and for the proper calibration of a flame speed model. Nevertheless, due to the chemical and physical properties of alcohols such as ethanol, this type of fuelling system leads to a significant non-uniformity of the mixture among the cylinders, and in some cases, to rich air-to-fuel ratio; numerical simulations are performed to address such an issue, and to evaluate performance and exhaust emissions, in terms of CO, CO₂, and NO_x. Finally, a study on spark timing variation is presented as well, to study its effect on performance and pollutants. Full article

This study utilizes a zero-dimensional, constant-pressure, perfectly stirred reactor (PSR) model within the Cantera framework to examine the combustion characteristics of hydrogen, methane, methanol, and propane, both singly and in hydrogen-enriched mixtures. The impact of the equivalence ratio (ϕ = 0.75, 1.0, 1.5), fuel composition, and residence duration on temperature increase, heat release, ignition delay, and emissions (NO_x and CO₂) is methodically assessed. The simulations are performed under steady-state settings to emulate the ignition and flame propagation processes within pre-chambers and primary combustion zones of internal combustion engines. The results demonstrate that hydrogen significantly improves combustion reactivity, decreasing ignition delay and increasing peak flame temperature, especially at short residence times. The incorporation of hydrogen into hydrocarbon fuels, such as methane and methanol, enhances ignition speed, improves thermal efficiency, and stabilizes lean combustion. Nevertheless, elevated hydrogen concentrations result in increased NO_x emissions, particularly at stoichiometric equivalence ratios, due to higher flame temperatures. The examination of fuel mixtures at varying hydrogen concentrations (10–50% by mole) indicates that thermal performance is optimal under stoichiometric settings and diminishes in both fuel-lean and fuel-rich environments. A thermodynamic model was created utilizing classical combustion theory to validate the heat release estimates based on Cantera. The model computes the heat release per unit volume (MJ/m³) by utilizing stoichiometric oxygen demand, nitrogen dilution, fuel mole fraction, and higher heating values (HHVs). The thermodynamic estimates—3.61 MJ/m³ for H₂–CH₃OH, 3.43 MJ/m³ for H₂–CH₄, and 3.35 MJ/m³ for H₂–C₃H₈—exhibit strong concordance with the Cantera results (2.82–3.02 MJ), thereby validating the physical consistency of the numerical methodology. This comparison substantiates the Cantera model for the precise simulation of hydrogen-blended combustion, endorsing its use in the design and development of advanced low-emission engines. Full article

In this paper, a novel technical route, namely combining the low-pressure exhaust gas recirculation (LP-EGR) and variable compression ratio (VCR), is proposed to address the inferior fuel economy for marine dual-fuel engines of low-pressure gas injection in diesel mode. To validate the applicability of the proposed technical route, firstly, a zero-dimensional/one-dimensional (0-D/1-D) engine simulation model with a predictive combustion model DI-Pulse is established using GT-Power. Then, parametric investigations on two LP-EGR schemes, which is implemented with either a back-pressure valve (LP-EGR-BV) or a blower (LP-EGR-BL), are performed to qualitatively identify the combined impacts of exhaust gas recirculation (EGR) and compression ratio (CR) on the combustion process, turbocharging system, and nitrogen oxides (NOx)-brake specific fuel consumption (BSFC) trade-offs. Finally, an optimization strategy is formulated, and an optimization program based on response surface methodology (RSM)–particle swarm optimization (PSO) is designed with the aim of improving fuel economy while meeting Tier III and various constraint conditions. The results of the parametric investigations reveal that the two LP-EGR schemes exhibit opposite impacts on the turbocharging system. Compared with the LP-EGR-BV, the LP-EGR-BL can achieve a higher in-cylinder pressure level. NOx-BSFC trade-offs are observed for both LP-EGR schemes, and the VCR is confirmed to be a viable approach for mitigating the penalty on BSFC caused by EGR. The optimization results reveal that for LP-EGR-BV, compared with the baseline engine, the optimized BSFC decreases by 10.16%, 11.95%, 10.32%, and 9.68% at 25%, 50%, 75%, and 100% maximum continuous rating (MCR), respectively, whereas, for the LP-EGR-BL scheme, the optimized BSFC decreases by 10.11%, 11.93%, 9.93%, and 9.58%, respectively. Furthermore, the corresponding NOx emissions level improves from meeting Tier II regulations (14.4 g/kW·h) to meeting Tier III regulations (3.4 g/kW·h). It is roughly estimated that compared to the original engine, both LP-EGR schemes achieve an approximate reduction of 240 tons in annual fuel consumption and save annual fuel costs by over USD 100,000. Although similar fuel economy is obtained for both LP-EGR schemes, LP-EGR-BV is superior to LP-EGR-BL in terms of structure complexity, initial cost, maintenance cost, installation space requirement, and power consumption. The findings of this study provide meaningful theoretical supports for the implementation of the proposed technical route in real-world engines. Full article

Solid oxide fuel cells (SOFCs) have garnered significant attention as a promising technology for clean and efficient power generation due to their ability to utilise renewable fuels such as hydrogen and ammonia. As carbon-free energy carriers, hydrogen and ammonia are expected to play a pivotal role in achieving net-zero emissions. However, a critical research question remains: how does the electrochemical performance of SOFCs compare when fuelled by hydrogen vs. ammonia, and what are the implications for their practical application in power generation? This mini-review paper is premised on the hypothesis that while hydrogen-fuelled SOFCs currently demonstrate superior stability and performance at low and high temperatures, ammonia-fuelled SOFCs offer unique advantages, such as higher electrical efficiencies and improved fuel utilisation. These benefits make ammonia a viable alternative fuel source for SOFCs, particularly at elevated temperatures. To address this, the mini-review paper provides a comprehensive comparative analysis of the electrochemical performance of SOFCs under direct hydrogen and ammonia fuels, focusing on key parameters such as open-circuit voltage (OCV), power density, electrochemical impedance spectroscopy, fuel utilisation, stability, and electrical efficiency. Recent advances in electrode materials, electrolytes, fabrication techniques, and cell structures are also highlighted. Through an extensive literature survey, it is found that hydrogen-fuelled SOFCs exhibit higher stability and are less affected by temperature cycling. In contrast, ammonia-fuelled SOFCs achieve higher OCVs (by 7%) and power densities (1880 mW/cm² vs. 1330 mW/cm² for hydrogen) at 650 °C, along with 6% higher electrical efficiency. Despite these advantages, ammonia-fuelled SOFCs face challenges such as NO_x emissions, nitride formation, environmental impact, and OCV stabilisation, which are discussed alongside potential solutions. This mini review aims to provide insights into the future direction of SOFC research, emphasising the need for further exploration of ammonia as a sustainable fuel alternative. Full article

Many cities are still struggling to comply with current air quality regulations. Road transport is usually a significant source of NOx emissions, especially in urban areas. Therefore, NOx from road vehicles needs to be further reduced below current standards to ultra-low or even zero-impact levels. In a novel, holistic powertrain design approach, this paper presents powertrain solutions to achieve zero-impact NOx emissions with an N1 class III diesel light commercial vehicle. The design is based on a compliance test matrix consisting of six real-world scenarios that are critical for emissions and air quality. As a design baseline, a vehicle concept meeting the emission requirements as set out in the European Commission’s 2022 Euro 7 regulation proposal is used. The baseline vehicle concept can achieve zero-impact NOx emissions in 67% of these scenarios. To achieve zero-impact NOx emissions in all scenarios, further advanced emission solutions are mandatory. In congested urban areas, the use of an exhaust gas aftertreatment system preheating device with at least 20 kW of power for 1 min is required. In high-traffic highway situations, an underfloor SCR unit with a minimum volume of 12 l or the restriction of the maximum vehicle speed at 130 km/h is required. Full article

Identifying and analyzing the engine performance and emission characteristics under the condition of performance decay is of significant reference value for fault diagnosis, condition-based maintenance, and health status monitoring. However, there is a lack of relevant research on the currently popular marine large two-stroke dual fuel (DF) engines. To fill the research gap, a detailed zero-/one-dimensional (0D/1D) model of a marine two-stroke DF engine employing the low-pressure gas concept is first established in GT-Power (Version 2020) and validated by comparing the simulation and measured results. Then, three typical types of turbocharger performance decays are defined including turbine efficiency decay, turbine nozzle ring area decay, and turbocharger shaft mechanical efficiency decay. Finally, the three types of decays are introduced to the engine simulation model and parametric runs are performed in both diesel and gas modes to identify and analyze their impacts on the performance and emission characteristics of the investigated marine DF engine. The results reveal that turbocharger performance decay has a significant impact on engine performance parameters, such as brake efficiency, engine speed, boost pressure, etc., as well as CO₂ and NOx emissions, and the specified limit value on certain engine operational parameters will be exceeded when turbocharger performance decays to a certain extent. The changing trend of engine performance and emission parameters as turbocharger performance deteriorates are generally consistent in both operating modes but with significant differences in the extent and magnitude, mainly due to the distinct combustion process (Diesel cycle versus Otto cycle). Furthermore, considering the relative decline in brake efficiency, engine speed drop, and relative increase in CO₂ emission, the investigated engine is less sensitive to the turbocharger performance decay in gas mode. The simulation results also imply that employing a variable geometry turbine (VGT) is capable of improving the brake efficiency of the investigated marine DF engine. Full article

In order to achieve the International Air Transport Association’s (IATA) goal of achieving net-zero emissions in the aviation industry by 2050, there has been a growing emphasis globally on the technological development and practical application of sustainable aviation fuels (SAFs). Discrepancies in feedstock and production processes result in differences in composition between SAFs and traditional aviation fuels, ultimately affecting the emission performance of the two types of fuel. This paper discusses the impact of CO₂/NO_x/SO₂/CO/PM/UHC emissions from the aviation industry on the natural environment and human health by comparing the two types of fuel under the same conditions. Fuel combustion is a complex process in the combustor of an engine, which transfers chemical energy into heat energy. The completeness of combustion is related to the fuel properties, including spray, evaporation, and flammability. Therefore, engine performance is not only affected by fuel performance, but also interacts with engine structure and control laws. The CO₂ emissions of SAFs differ significantly from traditional aviation fuels from a lifecycle analysis perspective, and most SAFs can reduce CO₂ emissions by 41–89%. Compared with traditional aviation fuels, SAFs and blended fuels can significantly reduce SO₂ and PM emissions. Pure Fischer–Tropsch hydroprocessed synthesized paraffinic kerosine (FT-SPK) can reduce SO₂ and PM emissions by 92% and 70–95% respectively, owing to its extremely low sulfur and aromatic compound content. In contrast, the differences in NO_x emissions between the two types of fuel are not significant, as their generation mechanisms largely stem from thermal drive and turbulent flow in the combustor, with emissions performance being correlated to power output and flame temperature profile in engine testing. CO and UHC emissions are related to engine operating conditions and the physical/chemical properties of the SAFs, with no significant upward or downward trend. Therefore, SAFs have significant advantages over conventional aviation fuels in terms of CO₂, SO₂, and PM emissions, and can effectively reduce the hazards of aviation to the environment and human health. Full article

In this study, the life cycle assessment (LCA) was used to compare the environmental performances of a conventional bulk carrier (baseline vessel) and a wind-energy-optimised bulk carrier equipped with modern on-board technologies working in synergy (future vessel). Fossil fuels was used for the baseline vessels, whereas the future vessel used liquefied biogas (LBG) and hydrotreated vegetable oil (HVO) as marine fuels. The entire life cycle phases of the vessels, namely, construction, operation, maintenance, and end-of-life, were included. The results showed that the future vessel could reduce 31.23% energy consumption, compared to the baseline model. Furthermore, the significant reduction in CO₂ (48.6%), NO_X (88.6%), SO_X (100.0%), and black carbon (94.0%) in the tank-to-wake phase was achieved owing to energy-saving technologies working in synergy and alternative fuels. This study emphasizes the vital role of energy efficiency, technologies, and alternative fuels to achieve the zero-emission ambition of the maritime industry. Furthermore, the impacts of ship construction, maintenance, and end-of-life need to be fully considered in order to decarbonize vessel from a life cycle perspective. Full article

This study explores the potentiality of low/zero carbon fuels such as methanol, methane and hydrogen for motor applications to pursue the goal of energy security and environmental sustainability. An experimental investigation was performed on a spark ignition engine equipped with both a port fuel and a direct injection system. Liquid fuels were injected into the intake manifold to benefit from a homogeneous charge formation. Gaseous fuels were injected in direct mode to enhance the efficiency and prevent abnormal combustion. Tests were realized at a fixed indicated mean effective pressure and at three different engine speeds. The experimental results highlighted the reduction of CO and CO₂ emissions for the alternative fuels to an extent depending on their properties. Methanol exhibited high THC and low NO_x emissions compared to gasoline. Methane and, even more so, hydrogen, allowed for a reduction in THC emissions. With regard to the impact of gaseous fuels on the NO_x emissions, this was strongly related to the operating conditions. A surprising result concerns the particle emissions that were affected not only by the fuel characteristics and the engine test point but also by the lubricating oil. The oil contribution was particularly evident for hydrogen fuel, which showed high particle emissions, although they did not contain carbon atoms. Full article

To achieve the European milestone of climate neutrality by 2050, the decarbonisation of energy-intensive industries is essential. In 2022, global energy-related CO₂ emissions increased by 0.9% or 321 Mt, reaching a peak of over 36.8 Gt. A large amount of these emissions is the result of fossil fuel usage in the motorised equipment used in mining. Heavy diesel vehicles, like excavators, wheel loaders, and dozers, are responsible for an estimated annual CO₂ emissions of 400 Mt of CO₂, accounting for approximately 1.1% of global CO₂ emissions. In addition, exhaust gases of CO₂ and NO_x endanger the personnel’s health in all mining operations, especially in underground environments. To tackle these environmental concerns and enhance environmental health, extractive industries are focusing on replacing fossil fuels with alternative fuels of low or zero CO₂ emissions. In mining, the International Council on Mining and Metals has committed to achieving net zero emissions by 2050 or earlier. Of the various alternative fuels, hydrogen (H₂) has seen a considerable rise in popularity in recent years, as H₂ combustion accounts for zero CO₂ emissions due to the lack of carbon in the burning process. When combusted with pure oxygen, it also accounts for zero NO_x formation and near-zero emissions overall. To this end, this study aims to examine the overall environmental performance of H₂-powered motorised equipment compared to conventional fossil fuel-powered equipment through Life Cycle Assessment. The assessment was conducted using the commercial software Sphera LCA for Experts, following the conventionally used framework established by ISO 14040:2006 and 14044:2006/A1:2018 and the International Life Cycle Data Handbook, consisting of (1) the goal and scope definition, (2) the Life Cycle Inventory (LCI) preparation, (3) the Life Cycle Impact Assessment (LCIA) and (4) the interpretation of the results. The results will offer an overview to support decision-makers in the sector. Full article

The problem of poor air quality in urban areas has a negative impact on the health of residents. This is especially important during periods of smog. In Poland, as in other countries, the problem of poor air quality, especially during the winter season, is associated with a high concentration of particulate pollutants in ambient air (PM₁₀, PM_2.5). Sources of particulate emissions, in addition to solid-fuel boilers, include means of transportation, especially those equipped with diesel engines. In turn, during periods of strong sunshine (spring and summer), the problem of photochemical smog, whose precursors are nitrogen oxides NO_X, arises in urban areas. Their main sources of emissions are internal combustion engines. Therefore, to improve air quality in urban areas, changes are being made in the transport sector, among which is upgrading the fleet of urban transport vehicles to low- or zero-emission vehicles, which are more environmentally friendly. In addition, measures that reduce the harmfulness of the transportation sector to air quality include the introduction of clean transportation zones, as well as park-and-ride (P&R) systems. The purpose of this article is to present the results in terms of PM₁₀, PM_2.5, and NOx emission reductions, implemented over a period of two years (2021–2022) in the area of the Rzeszow agglomeration, related to the modernization of the suburban bus fleet and the implementation of a P&R system for passenger cars. The results of the study were compared with the value of estimated emissions from coal-fired boilers used for residential heating and hot water, which also contribute to smog. Thanks to the implementation of the project, i.e., the replacement of 52 old buses with new buses of the Euro VI emission class and the construction of new P&R spaces, the total average annual reduction in emissions amounted to approximately 703.6 kg of PM₁₀, approximately 692.7 kg of PM_2.5, and a reduction of approximately 10.4 tons of NO_X. Full article

The use of zero-carbon and carbon-neutral fuels reduces emissions of conventional pollutants, but their emissions can be toxic and have various adverse effects on human health. This article reviews the possible combustion products of zero-carbon and carbon-neutral fuels, as well as their cytotoxic effects and potential health risks. At the same time, the review outlines biological models and toxicity detection methods commonly used in pollutant toxicity studies. Metals, nitrogen oxides (NO_X), and ammonia (NH₃) emitted from the combustion of metal fuels, hydrogen fuels, and ammonia fuels in zero-carbon fuels are harmful to human health. Exhaust emissions from carbon-neutral fuels, particularly biodiesel, and their blends with gasoline/diesel are cytotoxic, leading to severe cellular damage, such as oxidative damage, inflammatory responses, DNA damage, cell death, or apoptosis. Moreover, the normal function of the human body’s respiratory, cardiovascular, immune, digestive, urinary, and nervous systems may also be impacted by these fuel emissions according to cytotoxic research. Cytotoxicity of fuel combustion products is usually related to the fuel type, time, dose, and cell line used in the experiment. This review provides some ideas for the exhaust emission management of zero-carbon and carbon-neutral fuels and human health assessment. It also presents a theoretical and experimental basis for further research, including in vivo experiments. Full article

Due to having zero carbon emissions and renewable advantages, hydrogen has great prospects as a renewable form of alternate energy. Engine load and hydrogen substitution rate have a considerable influence on a hydrogen–diesel dual-fuel engine’s efficiency. This experiment’s objective is to study the influence of hydrogen substitution rate on engine combustion and emission under different loads and to study the impact of exhaust gas recirculation (EGR) technology or main injection timing on the engine’s capability under high load and high hydrogen substitution rate. The range of the maximum hydrogen substitution rate was determined under different loads (30%~90%) at 1800 rpm and, then, the effects of the EGR rate (0%~15%) and main injection timing (−8 °CA ATDC~0 °CA ATDC) on the engine performance under 90% high load were studied. The research results show that the larger the load, the smaller the maximum hydrogen substitution rate that can be added to the dual-fuel engine. Under each load, with the increase of the hydrogen substitution rate, the cylinder pressure and the peak heat release rate (HRR) increase, the equivalent brake-specific fuel consumption (BSFC_equ) decreases, the thermal efficiency increases, the maximum thermal efficiency is 43.1%, the carbon dioxide (CO₂) emission is effectively reduced by 35.2%, and the nitrogen oxide (NOx) emission decreases at medium and low loads, and the maximum increase rate is 20.1% at 90% load. Under high load, with the increase of EGR rate or the delay of main injection timing, the problem of NOx emission increases after hydrogen doping can be effectively solved. As the EGR rate rises from 0% to 15%, the maximum reduction of NOx is 63.1% and, with the delay of main injection timing from −8 °CA ATDC to 0 °CA ATDC, the maximum reduction of NOx is 44.5%. Full article

Ship engine combustion emits several atmospheric pollutants, such as PM, SOx, and NOx, which can have adverse health effects and are significant contributors to decreased air quality. Due to the distribution of maritime transport activity routes in the EU, a large portion of the population is exposed to shipping emissions throughout Europe. Therefore, in light of the European Commission long-term objective of “zero-waste, zero-emission” for maritime transport, the focus of this study was to quantify the impact of shipping emissions in the present, as well as the future, considering both emissions projection for the shipping sector and a climate change scenario. The WRF-CHIMERE modelling system was used to quantify the impact of shipping in Europe. To obtain the current and future contributions of maritime transport to the total pollutant concentrations, simulations were divided into two present (baseline and without shipping) and three future scenarios (shipping projection, climate change, and shipping projection and climate change). The results indicate that the current and future impacts of shipping emissions on pollutant concentrations are similar in some regions (NO₂ for Northern Europe and SO₂ for Southern Europe), which is due to the enforcement of emission control areas for those pollutants. However, efforts towards lowering emissions from the shipping sector are negated in the south of this domain due to the concentration changes caused by the climate change scenario. In light of these changes, the introduction of a NECA is proposed for the Mediterranean, which would help us to make great strides to reduce the impact of the shipping sector in the region and aid in counteracting the effects of climate change. Full article