Traditional Fuels Research Articles

Assessing the drivers of energy supply and demand in Sub-Saharan Africa

Ensuring reliable and sustainable energy access in sub-Saharan Africa requires exploring alternatives to traditional biomass and fossil fuels, crucial for overcoming challenges related to limited electricity and clean cooking energy access. Within this background and to assess the factors affecting energy supply and energy consumption, the Logarithmic Mean Divisia Index (LMDI) was applied across 48 sub-Saharan countries and adapted to the regional context considering energy access indicators.Key results showed that economic activity significantly influences both supply and demand growth. However, this growth is restricted by outdated infrastructure, resulting in inefficiencies and increased conversion losses. Policymakers thus face a dual challenge of promoting economic growth while modernizing energy infrastructure to sustain development.Moreover, targeted policies are essential, particularly in energy-intensive in energy-intensive sectors like wholesale and retail, while advocating for a comprehensive approach in the residential sector. This approach involves socioeconomic considerations, energy access enhancement, and the promotion of energy-efficient and renewable technologies to meet rising demand amid population growth and evolving consumption patterns.Furthermore, the study underscores the importance of enhancing both energy access levels and energy efficiency in the residential sector. Unlike the industrial sector, energy intensity is crucial for improving efficiency without compromising the level of access. Enhancing energy efficiency can significantly reduce energy consumption in households, which is important given the high reliance on energy-intensive practices such as cooking with traditional biomass.

Crimes associated with geological materials: mining, minerals, metals and fossils

Civilization has always relied on geological materials and it would not exist as we know it without the use of minerals. For the foreseeable future, minerals will remain fundamentally important commodities. As technology changes, so does the demand for different mineral commodities. For example, as we enter the era of the battery revolution, expedited by vehicle electrification and a reduction in the burning of traditional fossil fuels (coal, oil and gas), demand for minerals used in battery technologies is predicted to increase significantly. In 2022 alone, the global mining industry had a value of over 2000 billion US dollars. Where such huge amounts of money are involved, it is unsurprising that criminal activity follows. Criminal activity in the mining, minerals and metals industries includes illegal mining and smuggling, theft (including adulteration and substitution), illegal trade in conflict minerals, fakes, fraud and environmental crime (e.g. pollution, contamination and degradation of the land, air and water). In this article, we provide an overview of the types of criminal activities associated with geological materials and the potential role of forensic geologists in mitigating the associated risks.

Advancing Hydrogen Sensing for Sustainable Aviation: A Metal Hydride Coated TFBG Optical Fibre Hydrogen Sensor

The aviation industry is undergoing a significant shift toward sustainability, with hydrogen emerging as a promising green fuel to reduce carbon emissions due to its high gravimetric energy density and clean combustion exhaust compared to traditional aviation fuels. However, realizing hydrogen's aviation potential requires advanced sensors to ensure safety and efficiency in challenging environments, particularly for monitoring hydrogen near high-temperature engines and cryogenic storage tanks. Fibre optic sensors offer an exceptional advantage in these demanding conditions due to their capacity to operate in harsh environments, their small size, immunity to electromagnetic interference, spark-free operation, and remote sensing capabilities. Metal hydrides are prominent sensing materials studied for hydrogen sensing, especially palladium (Pd). Nonetheless, existing literature pertaining to Pd-coated fiber optic sensors for hydrogen detection has brought to light concerns regarding response hysteresis, stability, and linearity of Pd hydrogen sensors, calling for innovative solutions. In response to these challenges, our research introduces an innovative fibre optic hydrogen sensor, introducing tantalum (Ta) based metal hydrides as the sensing material. The sensor's construction involved the deposition of a nanometer-thick Ta thin film onto the surface of a tilted fibre Bragg grating (TFBG) using a magnetron sputtering technique. The sensing mechanism relies on the modulation of optical constants of the Ta thin film in response to even minute hydrogen concentrations, culminating in spectral changes in the transmission spectrum of the TFBG. In this proof of concept work, changes in both amplitude and the centre wavelength of cladding resonances of the TFBG transmission spectrum were observed in the hydrogen concentration range from 0.01% to 4% at room temperature. These initial findings underscore the substantial potential of our approach in developing highly sensitive and robust fibre-optic hydrogen sensors tailored specifically for hydrogen-powered aviation.

Experimental investigation of dairy biogas as fuel for a molten carbonate fuel cell

AbstractThis article presents the results of an experimental study evaluating the performance of a molten carbonate fuel cell (MCFC) using dairy biogas as a fuel source. Dairy biogas, a renewable byproduct of dairy farming, was compared with hydrogen in terms of operational efficiency. The investigation focuses on the performance parameters and efficiency metrics of MCFCs when powered by dairy biogas, relative to natural gas and hydrogen. The results demonstrate that while dairy biogas can power MCFCs, its efficiency and fuel utilization rates are lower than those of conventional fuels. This study contributes to an understanding of alternative, sustainable fuel sources for MCFC operations. During the study, the performance parameters of dairy biogas were compared with hydrogen, which served as a benchmark fuel. It was observed that in comparison with natural gas, commonly used as a fuel, dairy biogas showed lower efficiency rates and reduced fuel‐utilization factors. This suggests that although dairy biogas can be used as a fuel source for MCFCs, its effectiveness might not be on par with traditional fuels like natural gas.

Exploring the performance of biodiesel-hydrogen blends with diverse nanoparticles in diesel engine: A hybrid machine learning K-means clustering approach with weighted performance metrics

Biodiesel, an eco-friendly fuel with lower greenhouse gas emissions, is a crucial alternative to traditional fossil fuels. Adding hydrogen and nanoparticles to biodiesel enhances diesel engine performance, reduces emissions, and improves fuel efficiency through better combustion and fuel atomization. In this study, various nanoparticles were experimented, and their performance, emission, and acoustic outcomes were systematically evaluated, resulting in a comprehensive ranking and clustering. The k-means clustering-Entropy-TOPSIS method is applied to weigh performance outcomes, rank the nanoparticles, and create clusters among them among best and worst, considering multiple criteria's in this study. This study further divides diverse nanoparticles into clusters, employing a hybrid machine learning k-means clustering method. The CO parameter carries the highest weight (57%), followed by UBHC (22%), owing to their significant variation induced by the addition of nanoparticles, surpassing the variability observed in other parameters. Manganese oxide nanoparticles exhibited superior performance across various critical parameters among all nanoparticles with a minimum centroidal distance of 25.97. Moreover, enrichment with hydrogen gas, combined with nanoparticles, significantly enhanced diesel engine performance, manifesting in an approximate 8 % increase in Brake Thermal Efficiency (BTE) and 23 % reduction in CO emissions. Identifying the optimal nanoparticles is crucial for enhancing biodiesel properties, and the paramount importance of hydrogen mixing lies in its potential to significantly improve combustion efficiency, emissions, and overall diesel engine performance.

Parameter fine tuning on CRDI engine operated with blends of grape biodiesel and diesel

This study investigates the feasibility of using grape biodiesel from the wine industry as a sustainable and cost-effective alternative to traditional fuels. The research focuses on optimizing key parameters like blend ratio, injection timing, injection pressure, engine load, and exhaust gas recirculation in a Common Rail Direct Injection engine to achieve low emissions without compromising performance. Due to grape biodiesel's higher viscosity, different energy content, and varying ignition delays compared to diesel, precise adjustments are essential for complete combustion and reduced emissions. This study uses response surface methodology and a Central Composite Design matrix to find the best values for a number of parameters in modern CRDI engines that use advanced electronic control units. Through fifty input combinations, the study aims to minimize specific fuel consumption, hydrocarbons, nitrogen oxides, and carbon monoxide while maximising brake thermal efficiency, brake mean effective pressure, and mechanical efficiency. The optimal configuration includes a fuel injection timing of 6° bTDC, an engine load of 82 %, 6.7 % EGR, 1000 bar injection pressure, and a 33 % grape biodiesel blend. These optimum input conditions yielded outputs of 3.55 bar BMEP, 31.85 % BTE, 64 % mechanical efficiency, 0.278 kg/kWh SFC, 0.127 % CO, 357 ppm NOx, and 8 ppm of HC. These adjustments ensure low emissions and efficient engine operation, highlighting grape biodiesel's potential as a viable alternative fuel.

Scenarios for the introduction of hydrogen in the global fuel and energy complex, taking into account the analysis of the economic prerequisites for the inclusion of hydrogen in the global energy balance

Subject. This article discusses possible scenarios for the development of the global hydrogen market in the context of changes in the global energy balance. Objectives. The article aims to determine the prospects for the inclusion of hydrogen in the world energy balance in the process of its transformation, and analyze the economic prerequisites for the use of hydrogen. Methods. For the study, I used a content analysis, comparative analysis, and statistical data. Results. The article presents the author-developed methodology for analyzing the economic prerequisites for the inclusion of hydrogen in the global energy balance, which includes an assessment of the full cost of the hydrogen chain, inertia factors, regulatory and subsidy costs, possible benefits from the use of hydrogen instead of traditional fuels, cost reduction, as well as the calculation of investment indicators. The article assesses forecasts and strategies for the development of hydrogen energy in the world. Conclusions and Relevance. Creating safe, low-cost and reliable ways to transport and store hydrogen will provide an opportunity to replace fossil fuels in the transportation market. The results of the study can be used in decision-making by states and energy companies regarding the development of hydrogen energy and investment in technologies for the production, transportation and storage of hydrogen.

Techno-economic assessment of high-temperature aquifer thermal energy storage system, insights from a study case in Burgwedel, Germany

High-temperature aquifer thermal storage (HT-ATES) is an effective method to mitigate the increasing greenhouse gas emissions, and it is attracting industry attention as an alternative to traditional fossil fuels for heating and cooling. However, the uncertainty of exploration and long profit cycles impede the popularization of HT-ATES technology. In this paper, to optimize HT-ATES evaluation and make the results more convictive, we demonstrate a numerical study based on a real district and a proven aquifer. An integrated HT-ATES model includes the wellbore and aquifer is used to simulate the fluid flow and heat transfer. Moreover, a dynamic economic assessment is demonstrated depending on the HT-ATES fluctuation performance. A 30-year HT-ATES cycling simulation shows that the wellbore and aquifer have had a continuous heating loss since the operation started. Working well and balancing the well lost 2.7% and 2.2% of total energy through the wellbore. The aquifer lost 4.1% of total energy due to heating transfer to overburden and other layers. HT-ATES could recover around 90% of stored total energy. The HT-ATES economic performance is affected by the heating store and production cycling, the benefit mainly comes from the heating production season. The initial investment and heat exchange efficiency between the HT-ATES & end-application system determines the levelized heat (LCOH) cost and payback time, the optimist case still needs 3 years to be profitable. HT-ATES have considerable green benefits, it could reduce local CO2 emissions 1937 t/year.

Engine & vehicle modeling for fuel assessment under local driving conditions

Automotive biofuels offer a promising alternative to traditional fossil fuels. Accurate evaluation of combustion and emissions in IC engines and vehicles is crucial. This research aimed at developing and validating an engine and vehicle simulation methodology to assess the fuel effect on vehicle consumption and emissions considering different driving cycles and the road slope (barely evaluated for fuels widely used in emerging markets). Two blends were tested: 20 % biodiesel (B20) and 20 % hydrotreated vegetable oil (HVO20) with Ultra-Low-Sulfur Diesel (ULSD). A light-duty diesel vehicle model was developed in GTSuite®, using emission maps from a calibrated steady-state engine model. Good agreement with experiments was found. Road slope in local DC significantly increased fuel consumption and CO, CO2, NOx, and PN emissions, reducing HC. Compared to ULSD, B20 reduced PN and HC by 27–35 % and 12–22.5 %, respectively. HVO20 had a smaller effect on PN but reduced HC emissions by up to 19.5 %. Neither blend significantly affected CO and CO2. B20 slightly increased NOx and fuel consumption, while HVO20 had no significant impact on these.

Dynamics of total and industrial energy use in Turkiye from 1991 to 2019: a case study

AbstractEnergy use is an indicator of economic growth. However, high energy intensity has two main disadvantages. First, low energy efficiency increases a country’s dependence on other countries, especially when the country lacks energy sources. Second, if the country’s energy needs are met using traditional fossil fuels, this increases its CO2 emissions and reduces its air quality. Improving energy efficiency and reducing energy intensity are essential to reach the sustainability targets. This paper investigates the determinants of energy use in Turkiye for the period 1991–2019 by taking a dual approach. First, utilizing the Tapio decoupling factor, the decoupling factor analysis is not only being done for total energy use and real GDP, but also for industrial energy use and industrial income. Second, the factors determining the country’s total energy use are also examined, followed by an investigation of the indicators of energy use in the industry sector, which is highly energy intensive. For the industrial sector, two different decomposition analyses are performed and results are compared. The refined Laspeyres index method is adopted, and for each analysis, three main factors are considered. The empirical findings demonstrate that the income effect and population effect increased Turkiye’s total energy use, whereas the energy intensity effect decreased it. The first decomposition analysis for the industrial energy use reveals partly contrasting results with the previously published articles. For the industry sector, the second analysis show that productivity and employment increased Turkiye’s sectoral energy use; however, the sector’s energy intensity reduced it. Turkiye achieved some success in terms of reducing energy intensity at the sectoral and aggregate levels; however, as the findings of the present study demonstrate, further efforts are needed to lessen the country’s energy dependence and also to achieve future environmental sustainability targets. Trends relating to the determining factors in total and sectoral energy use are also compared in this paper, and some policy implications are presented.

Flame propagation behavior inside a closed duct upstream of a flame arrester housing

A possible way to introduce hydrogen into the energy matrix would be to enrich traditional fuels like natural gas and propane with hydrogen. Therefore, the study of the flame propagation behavior of these hydrogen enriched fuels becomes important to future industrial applications. In the present work the aim was to experimentally study the effect of hydrogen enrichment of propane and natural gas. However, in order to achieve more generality, the studied mixtures were characterized through the Lewis (Le), Zeldovich (Ze) and the reaction Damköler (Da°) numbers. A total of six mixtures were considered, in which the Ze varied from 4.94 to 8.45, the Le varied from 0.71 to 1.36 and the Da° varied from 14.56 to 36.11. In addition, the obtained results were compared to previous work to assess the effect of the experimental boundary conditions on the flame propagation velocity. The experimental results show that, for mixtures with similar Le numbers, the lower the Ze number the higher the flame propagation velocity. The maximum propagation velocities obtained in the first propagation section of the module are between 18.60 m/s and 57.11 m/s. Therefore, these flames can be considered as weakly accelerating flames. Moreover, the maximum flame propagation velocities showed a good correlation with the product Le × Ze. Regarding the presence of the flame arrester housing without an arrester element, it was observed that it causes an increase in flame propagation velocity. However, when compared to a previous work in which a flame arrester element was inside the housing, the velocity was higher for the present work.

Comparison of Emission Properties of Sustainable Aviation Fuels and Conventional Aviation Fuels: A Review

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/NOx/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 NOx 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.

Syngas application in various engines

Current engines are not designed to use syngas as fuel, which presents challenges such as differences in air-to-fuel ratio and fuel properties compared to traditional fuels like gasoline and diesel. This research recommends applying dual combustion, regulating pressure rate, using catalysts and employing EGR (exhaust gas recirculation), in order to improve engine efficiencies while reducing emissions. This study concludes that syngas is more effectively utilized in diesel and HCCI engines (homogeneous charge compression ignition) than in gasoline engines due to the cycle variations impacting efficiency. With technological advancements, syngas and other alternative fuels can be developed to reduce emissions and production cost, justifying their implementation.

Transformation of organosolv lignin into sustainable aromatics: Catalytic hydrodeoxygenation using carbon-supported bimetallic MoRu catalyst

While lignin holds potential as a sustainable source for fuels and chemicals, it faces hurdles due to its large molecular size, low heating values, and high oxygen content. In this study, the reductive depolymerization of organosolv lignin was investigated using mono-/bimetallic carbon-supported catalysts. At 340 °C, the MoRu/AC catalyst significantly reduced organosolv lignin feed's molecular weight from 2600 to 460 g/mol, yielding ∼70 % depolymerized organosolv lignin with a higher heating value of 32.92 MJ/kg, mainly composed of substituted phenolic compounds/aromatic hydrocarbons. Conversely, the MoRu/ACP catalyst underperformed, possibly due to residual acidity triggering undesirable side reactions like condensation. Thorough investigations revealed that introducing Mo into Ru catalysts significantly influences the hydrodeoxygenation process, resulting in H/C and O/C ratios of 1.29 and 0.20, contrasting with the initial feed's 1.05 and 0.35 ratios. Furthermore, density functional theory calculations showed lower energy barriers for breaking Caryl−OH/Caryl−O* bonds in guaiacol, a model compound, due to MoRu interactions, implying a promising deoxygenation potential for organosolv lignin transformation. The successful production of high-value bio-oil from technical lignin using the MoRu catalyst showcases its potential to pave the way toward carbon neutrality by offering eco-friendly alternatives to traditional fossil fuels and chemicals.

Assessing the particulate matter emission reduction characteristics of small turbofan engine fueled with 100 % HEFA sustainable aviation fuel

With the continuous increase in global air transportation, the impact of ultrafine particulate matter (PM) emissions from aviation on human health and environmental pollution is becoming increasingly severe. In addition to carbon reduction throughout the lifecycle, Sustainable Aviation Fuels (SAF) also represent a significant pathway for reducing PM emissions. However, due to issues such as airworthiness safety and adaptability, existing research has mostly focused on the emission performance of SAF when blended with traditional fuels at <50 %, leaving the emission characteristics of higher blending ratios to be explored. In this study, using measurement methods recommended by the International Civil Aviation Organization (ICAO), the PM emission reduction characteristics of small turbofan engines fueled with 100 % Hydroprocessed Esters and Fatty Acids (HEFA)-SAF were experimentally evaluated and compared with traditional fuels RP-3 and Diesel, while avoiding the interference of lubricant blending combustion. The results showed that the peak number concentration of particle size distribution (PSD), PM total number, as well as the number and mass concentration of non-volatile particulate matter (nvPM) decreased initially and then increased with rising thrust conditions. HEFA-SAF exhibits PSD with smaller diameters, and the Geometric Mean Diameter (GMD) ranges from 7.7 nm to 20.3 nm under all conditions. Both volatile particulates (vPM) and nvPM from HEFA-SAF are significantly reduced, with nvPM number emission index (EIn) being 92 % and 71 % lower than Diesel and RP-3, respectively. The nvPM mass emission index (EIm) also shows reductions of 96 % and 89 % compared to Diesel and RP-3. Microscopic characterization also indicated that using HEFA-SAF emitted fewer and smaller PMs. This study establishes a foundation for evaluating the effectiveness of 100 % SAF in reducing PM emissions within the aviation sector, and contributes to the airworthiness regulations development related to the use of SAF in a variety of application environments, alongside enhancing environmental protection measures.

The Impact of the Bursting New Energy Vehicle Market on the Traditional Fuel Vehicle Industry - The Case of Audi

The automotive industry is facing an era of change against the backdrop of escalating environmental concerns and a global shift towards sustainable transportation. This thesis focuses on the impact of the emerging New Energy Vehicle (NEV) market on Audi, a stalwart of the traditional fuel vehicle segment. The purpose of this study is to assess how Audi is responding to this transition, with particular emphasis on its strategy of embracing electrification in the face of increased competition and changing consumer preferences. Through a comprehensive literature review, analysis of Audi's financial reports and sales data, this study provides insights into Audi's investment in electrification, the pace of model launches, and sales of hybrid and all-electric vehicles. The data for this study was obtained from official Audi publications, industry reports, and relevant academic articles. The findings show that Audi has made significant progress in adapting to the new energy vehicle market, as evidenced by significant investment in electric vehicles, an expanding portfolio of electric models, and sales growth in key markets.

The fuel property and application prospect of water-containing biofuel from Clostridium acetobutylicum fermentation products

Biobutanol, a promising green alternative fuel, fermented from Clostridium acetobutylicum, while its high-cost and limited yield constraining its development. ABE (acetone-butanol-ethanol) and IBE (isopropanol-butanol-ethanol) are mixed fermentation products from non-edible biomass raw materials, using them together with water as alternative fuels will reduce industrial production costs and save fossil fuels. Therefore, this study conducted a multifaceted experimental evaluation on ABE/IBE mixed fuels with different water content, demonstrating that it has good water holding capacity when mixed with traditional fossil fuels. Taking ABE (3: 6: 1) as an example, its water holding capacity after mixing with diesel at 10–90 % is 0.37–7.83 % at 20 °C. Meanwhile, the particle size of ABE/IBE mixed fuels is about 2–30 nm, exhibiting a microemulsion with thermodynamic stability. The anhydrous or water-containing mixed fuel with the ratio of ABE (IBE) of 10%–50 % meets the range of the density and kinematic viscosity of diesel engine fuel. The mixed fuel is non-corrosive to copper without water, and a water content of about 3 % or higher will increase the risk of engine corrosion at 20 °C. Despite the addition of biofuel and water, studies on energy combustion performance and pollutant emission performance have found that appropriate addition of biofuel and water can produce higher power output and lower pollutant emissions than traditional fossil fuels, with ABE20W0.5 being the optimal. This study demonstrates the great potential of ABE and IBE as biofuels to achieve carbon neutrality goals, providing novel research direction for green alternative fuels in the future.

Harnessing Biogas Resources for Production of Methane Gas

Nigeria faces a significant challenge in providing reliable and affordable cooking fuel, particularly in rural areas and educational institutions. Reliance on traditional biomass fuels like firewood and charcoal contributes to deforestation, environmental degradation, and respiratory health problems. Additionally, access to Liquefied Petroleum Gas (LPG) can be limited and expensive. This project presents the design and construction of a 100-liter fixed-dome biogas plant for cooking applications. The plant was constructed using readily available materials, focusing on affordability and ease of assembly. The project aimed to harness organic waste and convert it into a sustainable and renewable fuel source. Following construction, the plant underwent a testing phase, successfully generating 5kg of biogas within 10 days. This highlights the plant’s potential for providing clean and sustainable cooking fuel in resource-constrained settings. This research contributes to ongoing efforts to address Nigeria’s fuel challenges by offering a localized, sustainable, and potentially cost-effective solution.

Assessment of Economic and Environmental Impacts of using Green Hydrogen Gas for Generating Electricity in the KSA

The energy sector in the Kingdom of Saudi Arabia (KSA) faces serious challenges regarding its current energy mix and energy policies. These challenges are even more complex in the sphere of electricity generation. Where on one side, these challenges are attributed to the fast-growing domestic demand for electricity. While on the other side, KSA depends extensively on traditional fossil fuels for generating electricity and hence facing high rates of carbon dioxide (CO2) emissions. To address these challenges, the Kingdom’s 2030 vision opted for economic diversification and decarbonization by encouraging the transition towards using green hydrogen gas for electricity generation as a clean energy source. This attempt has been associated with measures addressing rationalization of the demand side for electricity. The objective of this paper is to explore the economic and environmental viability of using green hydrogen gas for generating electricity in KSA. Working toward this objective, an economic assessment has been applied to five hypothetical cases or scenarios to identify the most cost-effective (least expensive) to run the turbine generator at net zero CO2 emission. In addition, an assessment of the environmental impact has been applied to the same five hypothetical cases or scenarios to identify the most environmentally friendly i.e., help effectively to reduce or minimize the CO2 emissions. The findings of this assessment reject the economic viability of the transition towards using green hydrogen gas for electricity generation in the KSA, where the calculations of the five cases registered an inverse relation between the NPV and the use of green hydrogen gas in electricity generation. These findings confirm the environmental variability of this transition, where the calculations of the five cases registered a positive relation between decarburization and the use of green hydrogen gas in electricity generation. Based on these findings, the economic ramifications and viability of this transition require a thorough investigation addressing economic and non-economic aspects.

Optimizing production conditions of innovative bio-pellets developed from flax straw

The increasing global demand for sustainable energy has prompted the utilization of agricultural residues as viable alternatives to traditional fossil fuels. This study specifically focuses on the utilization of flax straw, a substantial by-product in Canadian agriculture, to produce innovative biofuels through the process of pelletization. To enhance the quality of the pellets, lignin extracted from flax straw was introduced as a novel and natural pellet binder. A comprehensive investigation was conducted to analyze effect of various parameters, including flax straw particle size, binder (lignin) content, moisture levels, and pelletization conditions on quality of produced pellets. It was observed that at a compressive force of 4000 N and a die temperature of 95 °C, pellets made from larger flax straw particles (300–355 µm) exhibited a density of 1016 kg/m³ and a mechanical durability of 26.4 %. Subsequently, by reducing the particle size to 75–106 µm, a marked enhancement in both density (1072 kg/m³) and durability (86.1 %, a 2.3-fold increase) was achieved. The incorporation of 10 % lignin into medium-sized flax straw particles (150–212 µm) increased pellet durability by 18.6 % from 73.5 % to 87.2 %. Introducing an optimal moisture content of 14 % to the flax straw resulted in a notable increase in both density (from 1036 to 1154 kg/m³) and durability (from 73.5 % to 90.6 %, a 23.3 % increase). Compressive force and die temperature positively affected pellet quality. Elevating the temperature from 75 to 115 °C in pellets made from 150 to 212 µm flax straw, modified with 10 % lignin and 14 % moisture content, led to a significant improvement in both density (1179 kg/m³) and durability (96.6 %, a 11.9 % increase). Physiochemical characteristics of flax straw, lignin, and the resulting pellets were explored using various techniques such as Fourier transform infrared, thermogravimetric analysis, and differential scanning calorimetry. These comprehensive investigations offer valuable insights for optimizing pellet materials and pelletization conditions and promoting the sustainable utilization of agricultural residues for bioenergy production.