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        <title>Frontiers in Fuels | New and Recent Articles</title>
        <link>https://www.frontiersin.org/journals/fuels</link>
        <description>RSS Feed for Frontiers in Fuels | New and Recent Articles</description>
        <language>en-us</language>
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        <pubDate>2026-08-07T03:33:47.817+00:00</pubDate>
        <ttl>60</ttl>
        <item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2026.1840089</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2026.1840089</link>
        <title><![CDATA[Utilization of Madhuca indica ash as a green catalyst for transesterification of Madhuca indica oil: process optimization and engine analysis]]></title>
        <pubdate>2026-07-03T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>S. Aparna</author><author>S. Rahul</author><author>D. Dhanuprabha</author><author>S. Raaghavi</author><author>A. Arumugam</author>
        <description><![CDATA[This study investigates a heterogeneous catalyst derived from calcined and NaOH-treated Madhuca indica (M. indica) shell ash for the transesterification of M. indica seed oil. Process parameters were optimized using a central composite design (CCD) within response surface methodology (RSM), resulting in a maximum biodiesel yield of 92.3% (GC-MS area-based ester content). The optimal conditions were a methanol:crude oil molar ratio of 22.5:1, a reaction temperature of 70 °C, a catalyst loading of 2.5 wt%, and a reaction time fixed at 6 h. Engine performance was evaluated on a single-cylinder diesel engine operating at 1,500 rpm, utilizing B10 and B20 biodiesel blends. Under full load conditions, B10 reduced hydrocarbon (HC), carbon monoxide (CO), and smoke emissions by 21.43%, 12.78%, and 5.97%, respectively. B20 reduced HC, CO, and smoke emissions by 27.55%, 20.3%, and 12.23%, respectively, relative to diesel. Nitrogen oxides (NOx) emissions increased by 8.37% for B10% and 17.1% for B20 relative to conventional diesel. A techno-economic analysis (TEA) was performed using an Aspen Plus economic analysis process model; results and underlying assumptions are detailed in the TEA section.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2026.1871799</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2026.1871799</link>
        <title><![CDATA[Municipal solid waste gasification with alcohol-to-jet upgrading produces low-carbon aviation fuel at fossil-competitive costs]]></title>
        <pubdate>2026-07-01T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Joseph Amponsah</author><author>Pallavi Dubey</author><author>Jian Shi</author><author>Mark Mba Wright</author>
        <description><![CDATA[IntroductionMunicipal solid waste is an abundant feedstock with established collection infrastructure and negative or near-zero acquisition costs. This study quantifies the techno-economic and environmental performance of a gasification and alcohol-to-jet pathway that converts 2,000 tonnes per day of municipal solid waste into sustainable aviation fuel.MethodsProcess modeling was conducted in BioSTEAM v2.44.3. Techno-economic analysis and life cycle assessment were performed, including Monte Carlo uncertainty analysis incorporating syngas H2/CO variability, catalyst lifetime, MSW moisture, plastic fraction, and financial parameters.ResultsThe process yields 9.3 gallons of fuel per tonne of incoming waste, with aluminum, iron, and propanol recovered as co-products. The minimum fuel-selling price (MFSP) ranges from $1.25 to $3.68 per gallon depending on tipping-fee credits and co-product revenues, with the lower bound within the 2019–2024 petroleum jet fuel range of $2.00–$3.50 per gallon. Cradle-to-gate global warming potential is 33.67 g CO2-eq/MJ, representing a 63% reduction relative to conventional jet fuel. Natural gas and electricity account for 54% of total emissions, while avoided landfill methane and metal recovery provide 5.8 g CO2-eq/MJ in credits. Monte Carlo analysis yields a 90% confidence interval of –$0.12 to $2.61/gal for MFSP and 28.4–42.8 g CO2-eq/MJ for GWP.ImplicationsEconomic performance is most sensitive to internal rate of return and aluminum price, while environmental performance is primarily driven by electricity sourcing and plastic composition. Overall, the pathway demonstrates robust climate benefits and competitive cost potential across uncertainty ranges.]]></description>
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        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2026.1860328</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2026.1860328</link>
        <title><![CDATA[Inducible two-step cultivation of microalgae: engineering the growth and lipid biosynthesis for biofuel production]]></title>
        <pubdate>2026-06-25T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Krishnakumar Mohan</author><author>Arathi Sreenikethanam</author><author>Subhisha Raj</author><author>Niharika Mondru</author><author>Amit K. Bajhaiya</author>
        <description><![CDATA[Microalgae have significant economic importance due to their fast growth and diverse biomass composition. However, achieving cost-effective large-scale production while maintaining the high yields of the desired metabolite remains a major challenge. Conventional cultivation strategies face an inherent trade-off: conditions that promote microalgae development often suppress metabolite synthesis, whereas stress conditions that induce the desired metabolite synthesis inhibit growth and overall biomass production. In recent years, there has been increasing interest in a two-step cultivation, in which microalgae are first grown under optimal conditions for maximal biomass, followed by exposure to stress to trigger targeted metabolite synthesis. Despite its advantages, this approach also faces limitations in precisely controlling metabolite induction and in avoiding undesirable stress responses. To overcome this issue, integrating inducible genetic switches in the second cultivation phase, particularly stress-responsive promoters linked to the gene of interest, offers a promising strategy to enhance metabolite production in a controlled manner. However, until now, there are no published studies on the utilization of inducible promoters along with a two-stage cultivation system for microalgae. The inducible systems are activated by specific stress factors or substrates, enabling targeted activation of desired pathways while limiting off-target effects. This review provides an overview of the mechanistic framework of the two-step cultivation system, types and mechanisms of inducible promoters, and switch-based metabolic regulation in microalgae. Finally, we will highlight the challenges and opportunities for integrating synthetic biology tools with cultivation engineering to enhance and sustain targeted metabolite production in microalgal biorefineries.]]></description>
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        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2026.1825931</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2026.1825931</link>
        <title><![CDATA[Laminar flame speeds of dimethyl ether-propane/butane/propylene air mixtures]]></title>
        <pubdate>2026-06-23T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Jordan Walsh</author><author>Dezheng Li</author><author>Yanming Chen</author><author>Yang Zhang</author><author>Ruoyang Yuan</author>
        <description><![CDATA[IntroductionDimethyl ether (DME) has potential to be used both blended with or as an alternative to Liquefied Petroleum Gas (LPG) to reduce the carbon emissions of a fuel used globally for cooking and heating. Standards to enable the adoption of this require flame speed measurements of the blends of these fuels.MethodsMeasurements of counterflow premixed flame speeds for blends of DME, propane, butane, and propylene at fuel-air equivalence ratios (φ) from 0.75 to 1.6 have been made. These measurements were taken to fill a gap in the current published datasets that primarily have focussed on pure fuels and blends of LPGs constituent gases. These measurements have been produced through a mixture of empirical and simulation work.ResultsWe found the flame speeds of the blends overall increase from 0.25 m/s at φ = 0.75 to between 0.4 m/s and 0.45 m/s at φ = 1.0 peaking around φ = 1.0 to 1.1 before decreasing as φ increases further.DiscussionThese data will be useful to support the production of industrial standards that allow for greater adoption of renewable DME as an alternative low carbon fuel to fossil LPG.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2026.1756561</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2026.1756561</link>
        <title><![CDATA[Pilot scale demonstration of potential for decarbonisation of industrial heating processes using hydrogen cofiring]]></title>
        <pubdate>2026-06-01T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Andrew D. Heeley</author><author>Karen N. N. Finney</author><author>János Szuhánszki</author><author>Abdulaziz Gheit</author><author>Jee Loong Hee</author><author>Mohamed Pourkashanian</author>
        <description><![CDATA[This paper aims to evaluate whether cofiring hydrogen and natural gas mixtures are suitable as industrial furnace fuels and to identify further characteristics that need more detailed understanding to enable successful implementation of fuel switching. The outcome of this research and further investigations will ensure that the full capability of fuel switching becomes available to energy-intensive process operators. Co-firing natural gas and hydrogen leading to dedicated hydrogen combustion are pathways to decarbonise industrial processes and can enable future hydrogen utilisation and interoperability with fossil fuels. The key observations from pilot-scale industrial furnace trials at the University of Sheffield Energy Innovation Centre included: (1) Radiant heat flux depended primarily upon furnace temperature with no relationship measured with varying fuel composition. (2) The chamber geometry, radiant heat flux from solid surfaces and control temperature achieved were more significant to the furnace heat exchange than the fuel mixture. (3) Firing with natural gas and hydrogen mixtures did not affect furnace temperature or uniformity beyond variations attributable to other process conditions. (4) Gas temperatures and species were distributed uniformly within the fully mixed atmosphere, which represented 2/3 of the chamber volume. (5) Gas temperature and species distributions were not affected by fuel composition, therefore measurements from the centre of the chamber were representative of the mean conditions in the fully mixed atmosphere. (6) CFD modelling of the gas and temperature distributions within the furnace enabled thermodynamic and fluid dynamic characteristics to be understood and afforded confidence in experimental and model outcomes. Co-firing hydrogen with natural gas and dedicated hydrogen firing as an interoperable fuel to substitute for natural gas could be a key means to decarbonise hard to abate foundation industries, whilst making continued use of existing capital assets. This investigation demonstrated that understanding hydrogen firing and co-firing will enable the mitigation of perceived risks arising from decarbonisation of energy-intensive industries with low and zero carbon fuels.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2026.1805792</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2026.1805792</link>
        <title><![CDATA[Bioethanol and biobutanol production using algal biomass: pathways and industrial applications]]></title>
        <pubdate>2026-05-22T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Ruchi Pathania</author><author>Pallavi Saxena</author><author>Subhasini Sahoo</author><author>Anupam Kundu</author>
        <description><![CDATA[The increase in global demand for sustainable and eco-friendly energy has intensified research on biofuels derived from renewable biomass. Among various feedstocks, algal biomass has attracted more attention due to its high photosynthetic efficiency, rapid growth rate, and ability to grow on non-arable land using saline or wastewater, thus avoiding competition with food crops. Bioethanol and biobutanol, in particular, have emerged as promising alternatives to fossil fuels because of their cleaner combustion, higher energy content, and compatibility with existing fuel infrastructure. This review provides a comprehensive overview of converting algal carbohydrates into fermentable sugars and then fermentation using microbial or genetically engineered organisms for bioethanol and biobutanol production. Various pretreatment and hydrolysis methods, including mechanical disruption, chemical treatments, thermal and biological processes, are discussed for their effectiveness in breaking down the complex algal cell walls and releasing fermentable sugars. Bioethanol is mainly synthesized through the glycolytic pathway and subsequent alcoholic fermentation, whereas biobutanol is produced through the Acetone-Butanol-Ethanol fermentation process. The review also discusses a comparative analysis of algal bioethanol and biobutanol in terms of their industrial applications and market potential. It addresses key challenges, including feedstock availability, process scalability, and production costs, while evaluating opportunities for integration within biorefinery frameworks to enhance overall economic feasibility. Overall, algal biomass represents a sustainable, versatile, and scalable resource for bioethanol and biobutanol production, offering significant potential to support the global transition toward renewable energy. Advancements in research, technological optimization, and supportive policy frameworks will be essential for utilizing the full industrial potential of algal-based biofuels.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2026.1831924</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2026.1831924</link>
        <title><![CDATA[Cyclic acetals as next-generation oxygenated diesel additives from lignocellulosic biomass and plastic waste]]></title>
        <pubdate>2026-05-22T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Anh Ngoc Dao</author><author>Malinee Sriariyanun</author><author>Punyanuch Kunmanee</author><author>Atthasit Tawai</author><author>Suksun Amornraksa</author>
        <description><![CDATA[The decarbonization of heavy-duty transport, marine shipping, and aviation require sustainable liquid fuels that are compatible with existing infrastructure and derived from renewable carbon sources without competing with food or land resources. Cyclic acetals, particularly 1,3-dioxolane and 1,3-dioxane derivatives, have recently emerged as promising oxygenated fuel candidates capable of integrating multiple bio-hybrid carbon streams. These compounds can be synthesized from lignocellulose biomass-derived diols and higher aldehydes, captured CO2 valorized with green hydrogen, and C1 intermediates obtained from plastic waste. Compared with traditional formaldehyde-based routes, the use of higher aldehydes and catalytic CO2/H2 conversion pathways helps overcome thermodynamic limitations and phase-separation challenges in acetal synthesis. Process intensification strategies, such as reactive extraction and reactive distillation in integrated catalytic columns, further enable simultaneous synthesis and purification, simplifying process design and improving scalability. Cyclic acetals exhibit favorable fuel properties, including full miscibility with conventional diesel and jet fuels, high cetane numbers, excellent cold-flow characteristics, and stable oxygenated structures resistant to corrosion and degradation during storage and combustion. These attributes make them attractive molecular platforms for advanced bio-hybrid fuels, enabling pathways toward carbon-neutral and potentially carbon-negative diesel and aviation fuels derived from biomass, CO2, and recycled plastics. Remaining challenges include catalyst durability, impurity tolerance, pilot-scale validation, and techno-economic feasibility.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2026.1748966</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2026.1748966</link>
        <title><![CDATA[The role of combustion (and fuels) in a decarbonizing world]]></title>
        <pubdate>2026-03-02T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Jörg Leicher</author><author>Anne Giese</author><author>Christoph Wieland</author>
        <description><![CDATA[Access to energy is essential for the modern world, yet at the same time, anthropogenic greenhouse gas emissions are caused by energy-related activities across all sectors due to the predominance of fossil fuels. Today, most of the primary energy is still being provided by fossil fuels, with combustion being a key technology. In order to combat climate change, energy has to be decoupled from greenhouse gas emissions, with electricity and electrification being important pathways towards a net-zero energy system. However, electricity also has drawbacks as an energy carrier, especially in the context of large-scale energy storage, but also for applications requiring high energy densities. This, in addition to providing dispatchable power generation capacities for grid balancing and covering longer periods of reduced renewable power generation, is expected to result in significant contributions of synthetic and biogenic fuels to the energy landscape. The main purpose of combustion-based technologies will change from providing most of the primary energy to the energy system to complementing variable renewable energies when and where needed. This change of purpose has consequences for the directions of combustion research and development: while traditional topics such as equipment efficiency and pollutant emissions such as NOX will still be important, other topics such as more flexible and dynamic operation modes, hybrid applications and system integration will play a much bigger role in the future, along with the use of new fuels such as hydrogen or ammonia.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2025.1670642</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2025.1670642</link>
        <title><![CDATA[Brown algae-functionalized clays as a novel biosupports for lead-free bismuth halide perovskites in the CO2 reduction]]></title>
        <pubdate>2026-01-16T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Emireth A. Mellado-Lira</author><author>Edith Luévano-Hipólito</author><author>Luis F. Garay-Rodríguez</author><author>Leticia M. Torres-Martínez</author>
        <description><![CDATA[IntroductionOne of the main environmental problems is air pollution due to high CO2 emissions, a greenhouse gas that contributes to climate change because of the excessive use of fossil fuels. For this reason, CO2 reduction emerges as a promising solution by converting it into renewable fuels using sunlight and advanced semiconductor materials. Recently, hybrid systems based on artificial leaves composed of lead-free halide perovskites and porous support materials have been demonstrated to be highly efficient for CO2 reduction. In addition, the recycling and utilization of natural sources such as the brown algae, considered a plague in the Caribbean, represents an additional advantage for the pollution reduction, carbon sequestration, and social and economic impacts.MethodsThis research proposes an innovative solution to address this environmental problem by demonstrating that hybrid systems based on bismuth halide perovskites (K3Bi2I9) and brown algae-functionalized clay biosupports are promising for the reduction of CO2 with high efficiencies for formic acid production (2.5 mmol h-1) under visible light. The content of the brown algae was investigated to find the best load that promotes higher and stable CO2 reduction efficiencies.ResultsThe presence of the brown algae enhanced light absorption by its chlorophyll, provided free electrons to the semiconductor and highly reactive species (•OH), that favored the formation of C1-C3 products, e.g., HCOOH, CH3COOH, and CH3(CH2)2OH, with efficiencies in the order of >1 mmol. In addition, the stability of the hybrid systems was demonstrated after five hours of continuous visible light irradiation in liquid phase, which analysis of the medium showed a minimal leaching of potassium.DiscussionThe addition of 5 wt.% brown algae in the clays promoted both high efficiency and stability of the hybrid system by preventing cracking, while promoting a porous framework that maintained effective CO2 adsorption. This enhanced effect was attributed to efficient perovskite encapsulation and the presence of chlorophyll (from algae) acting as an electron donor, enhancing light absorption and charge transfer. This synergistic effect enabled efficient CO2 conversions to C1–C3 value-added products. In conclusion, this work demonstrated that the utilization of abundant natural materials such as clays and sargassum supports an ecological and scalable approach while addressing global and local environmental problems.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2025.1716359</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2025.1716359</link>
        <title><![CDATA[Tailored porosity from waste biomass: mesoporous bio-adsorbents for targeted treatment of complex industrial wastewaters]]></title>
        <pubdate>2026-01-14T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Saqib Sohail Toor</author><author>Kamaldeep Sharma</author><author>Rebekka Klemmt</author><author>Mohammad Aref Hasen Mamakhel</author><author>Abdenour Achour</author>
        <description><![CDATA[The valorization of waste biomass into tailored adsorbents presents a sustainable strategy for combating industrial water pollution. This study highlights the critical role of precursor morphology in determining the textural properties and function of bio-adsorbents derived from wheat straw (WS) and the organic fraction of municipal solid waste known as biopulp (BP). Through carbonization and KOH activation, the fibrous WS was transformed into a microporous, high-surface-area activated wheat straw (AWS) bio-adsorbent, while the compact BP yielded a mesoporous network in activated biopulp (ABP). This structural difference affects adsorption performance: AWS demonstrated superior efficacy in batch removal of phenols (93.2%) and total organic carbon (85%) from the complex hydrothermal liquefaction aqueous phase (HTL-AP), whereas ABP excelled in treating produced water (PW), achieving >95% removal of organic pollutants. Continuous fixed-bed column studies confirmed the scalability of AWS for HTL-AP treatment, revealing distinct breakthrough dynamics between bulk parameters and specific contaminants. This work provides evidence supporting precursor-dependent tailoring of pore structure for targeted wastewater treatment, providing a possibility for a circular and sustainable solution for the treatment of complex industrial wastewaters.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2025.1722932</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2025.1722932</link>
        <title><![CDATA[Composition-centered prediction of kenaf core saccharification for next-generation bioethanol via machine learning]]></title>
        <pubdate>2025-11-21T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Yitong Niu</author><author>Ying Ying Tye</author><author>Chee Keong Lee</author><author>Mardiana Idayu Ahmad</author><author>Cheu Peng Leh</author>
        <description><![CDATA[IntroductionBiomass pretreatment outcomes are heterogeneous across routes and severities, and condition-centered empirical models often fail to generalize beyond the settings on which they were trained, limiting early-stage decisions about where to focus costly wet-lab effort. This study evaluates a composition-centered surrogate that treats the post-pretreatment solid composition—cellulose, hemicellulose, lignin—as the input space and predicts enzymatic glucose yield as the response for kenaf core.MethodsKenaf core solids subjected to water, dilute-acid, and alkaline pretreatments were characterized for post-pretreatment cellulose, hemicellulose, and lignin contents and hydrolyzed under a fixed enzymatic protocol to obtain glucose yield at 24 h. The curated dataset (n = 35) was used to train Random-Forest regressors tuned by six hyperparameter optimizers (grid search, random search, Bayesian optimization, genetic algorithm, particle swarm optimization, and simulated annealing). Generalization performance was assessed using nested cross-validation and a held-out test split, with feature contributions examined via permutation importance and accumulated local effects.ResultsAcross optimizers, held-out performance clustered tightly (test R2 ≈ 0.49–0.55; RMSE 4.42–4.69 GY%), indicating that attainable accuracy is governed more by model capacity and data coverage than by optimizer choice. Feature diagnostics converged on a cellulose-led mechanism, with cellulose showing a positive monotonic effect on yield, lignin a negative effect, and hemicellulose a weaker, context-dependent influence. Iso-yield maps in the cellulose–lignin plane delineated feasible composition windows that prioritize high-cellulose/low-lignin regions under different hemicellulose levels.DiscussionWithin this accuracy band, the composition-centered surrogate is best suited for uncertainty-aware screening to prune unproductive regions of composition space before targeted design-of-experiments, rather than replacing detailed process optimization. The workflow provides a transferable template for small-sample, composition-based modeling of lignocellulosic feedstocks and can be extended to other varieties and integrated with mechanistic descriptors as data accumulate.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2025.1674030</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2025.1674030</link>
        <title><![CDATA[Italy’s biomethane investment under the national recovery and resilience plan: a flagship initiative for Europe’s sustainable fuel transition]]></title>
        <pubdate>2025-10-15T00:00:00Z</pubdate>
        <category>Opinion</category>
        <author>Giorgio Centurelli</author>
        <description></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2025.1643675</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2025.1643675</link>
        <title><![CDATA[Microalgae: Promising solutions paving the way toward a greener and more sustainable future]]></title>
        <pubdate>2025-08-18T00:00:00Z</pubdate>
        <category>Mini Review</category>
        <author>Yunhan Qin</author><author>Tingfu Li</author><author>Changliang Nie</author><author>Xueyun Geng</author><author>Xiaomin Sun</author>
        <description><![CDATA[Microalgae represent a promising solution for achieving greener and more sustainable applications, owing to their rapid growth rates, high photosynthetic efficiency, and capacity to produce valuable compounds such as lipids. Biofuels based on microalgae have emerged as a promising alternative to fossil fuels due to their sustainable and renewable nature. Moreover, the use of microalgae cultivated in wastewater not only contributes to biofuel production but also provides additional benefits such as wastewater treatment and CO2 sequestration to realize the carbon neutrality. However, the commercial viability of microalgae-based biofuels remains uncertain. This article reviews advancements in microalgae-based sustainable production while exploring its multi-objective applications beyond energy generation. Multi-objective applications, including multi-algal systems, species development, process optimization, and dust suppressant are necessary to improve cost-effectiveness and enhance overall feasibility.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2025.1528451</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2025.1528451</link>
        <title><![CDATA[Achieving biodiesel standards through saturation level optimisation]]></title>
        <pubdate>2025-03-04T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Kemal Masera</author><author>Abul Kalam Hossain</author><author>Gareth Griffiths</author>
        <description><![CDATA[Biodiesels made from waste feedstock are viable sustainable fuels for compression-ignition engine use. However, biodiesels produced from single waste sources do not always comply with the European biodiesel standard. This study investigates fuel quality and engine performance when two biodiesels with different characteristics are blended at various proportions. Waste cooking oil biodiesel was blended with sheep fat biodiesel, which has a lower unsaturated fatty acid content. The engine performance, combustion, and exhaust emission characteristics of the neat biodiesels and their blends (at 60/40, 50/50, and 30/70 ratios) were analysed. The results showed that 60/40 and 50/50 blends met the core parameters of the BS EN 14214 biodiesel standard and improved combustion and emission characteristics compared to neat biodiesels and diesel. The 50/50 blends gave up to 5% and 14% improvements in the in-cylinder pressure and maximum heat release rate, respectively, compared to the same results for neat biodiesel operation. Reduction of up to 73% in CO, 96% in smoke and 3% in CO2 emissions was observed. However, NOx emission was 2.5% higher than diesel. The results reveal that carefully selected biodiesel–biodiesel blending could meet fuel standards, improve engine performance, and reduce exhaust emissions.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2025.1464944</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2025.1464944</link>
        <title><![CDATA[A geographic information systems selection approach to repurposing offshore oil & gas assets for green hydrogen production]]></title>
        <pubdate>2025-02-24T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>William Rupp</author><author>Karim Rabea</author><author>Ruoyang Yuan</author>
        <description><![CDATA[Integrating green hydrogen production with existing oil and gas infrastructure is seen as viable step for the reutilization of oil and gas assets. Green hydrogen production through offshore wind has the potential to extend the lives of these systems, reduce decommissioning costs and provide a source of clean energy. This paper presents an outlook on wind license areas using existing oil and gas infrastructure. Three scenarios are proposed for the conversion of offshore assets into wind turbine sites, including the conversion of a platform into a substation. A methodology is provided to assess the suitability of offshore wind using exclusion criteria and the cessation of production dates for oil and gas infrastructure. This methodology is applied to the UK Exclusive Economic Zone (EEZ), and the results show that 7.4% of the UK EEZ is within the top suitability index for wind turbine development. The cost of green hydrogen production from different offshore locations is estimated to be in the range of 9.78–11.76 £/kgH2 depending on the wind farm scale and the distance. The study highlights the potential for using existing infrastructure for wind turbine development and provides valuable insights for stakeholders in the energy industry.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2024.1404367</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2024.1404367</link>
        <title><![CDATA[Methane emission reduction through hydrogen blending in a large bore 2-stroke lean-burn natural gas compressor engine]]></title>
        <pubdate>2024-12-09T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Greg Vieira</author><author>Rachel Lorenzen</author><author>Mark Patterson</author><author>Daniel Olsen</author>
        <description><![CDATA[Impending and increasingly stringent emissions regulations regarding natural gas compressor engines drive the research behind blending hydrogen with natural gas to make these internal combustion engines and their combustion process more efficient. This investigation seeks to answer two fundamental questions: will blending hydrogen with natural gas reduce overall engine fuel consumption, and can greenhouse gas emissions be reduced by blending hydrogen with natural gas? A 4-cylinder Cooper–Bessemer GMV engine, housed at Colorado State University’s Powerhouse facility, was investigated for hydrogen–natural gas blending using multiple engine configurations. A lean-burn engine uses an active pre-combustion chamber as its ignition source, along with electronically activated high pressure fuel injection in the main combustion chamber. One configuration tested utilized high-pressure fuel injection and blending in hydrogen, up to 40% by volume, in both the main chamber and pre-combustion chamber fuel supplies. A second configuration, where the main combustion chamber fuel was solely natural gas and only the pre-combustion chamber received hydrogen-blended natural gas, was also tested. The final configuration to be tested used low pressure fuel injection with mechanically actuated valves in the main chamber with a traditional spark plug ignition source. All engine configurations saw reductions in methane emissions of up to 30% using blended natural gas and hydrogen. Carbon dioxide emissions were also shown to be reduced for the two configurations. A reduction in brake-specific fuel consumption of up to 2% was also seen for two configurations. These results support the hypothesis that blending hydrogen into natural gas can reduce engine total fuel consumption and reduce greenhouse gas emissions.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2024.1401691</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2024.1401691</link>
        <title><![CDATA[A quantitative study of OH and NO concentration of a premixed laminar kerosene flame using a flat-flame burner at atmospheric pressure]]></title>
        <pubdate>2024-11-18T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Si Shi</author><author>Kevin J. Hughes</author><author>Mohamed Pourkashanian</author>
        <description><![CDATA[In the context of global warming and the increasing demands for the application of sustainable fuels, measurements of a variety of experimental targets under a wide range of conditions are crucial to improving the fundamental understanding of real jet fuels and developing quality kinetic mechanisms for large hydrocarbons. Planar laser-induced fluorescence (PLIF) is an effective approach to investigate concentrations of important species of a given flame while quantifying the fluorescence image remains a great challenge with significant uncertainties. This investigation aims to improve the fundamental understanding of the oxidation of kerosene-based mixtures at two equivalence ratio conditions. Two gas fuels are utilized as the reference for the quantitative studies. For each flame condition, relative OH and NO quantities and temperature profiles were measured by applying the PLIF and coated fine wire type R Pt/Pt-Rh thermocouples, respectively. The converted OH and NO results were subsequently compared with the simulation by using ANSYS Chemkin Pro, and the results indicate that reliable temperature profiles are the key to accurately quantify the species concentration of a given flame.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2024.1416716</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2024.1416716</link>
        <title><![CDATA[Hydrogen-natural gas fuel blending in a “rich burn” engine with 3-way catalyst]]></title>
        <pubdate>2024-09-13T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Nicholas Katsampes</author><author>David Montgomery</author><author>Gregg Arney</author><author>Daniel B. Olsen</author>
        <description><![CDATA[Interest in hydrogen (H2) fuels is growing, with industry planning to produce it with stranded or excess energy from renewable sources in the future. Natural gas (NG) utility companies are now taking action to blend H2 into their preexisting pipelines to reduce greenhouse gas (GHG) emissions from burning NG. Stoichiometric (“rich burn”) NG engines that operate on pipeline NG and will receive blended fuel as more gas utilities expand H2 production. These engines are typically chosen for their low emissions owing to the 3-way catalyst control, so the focus of this paper is on the change in emissions like carbon monoxide (CO) and nitrogen oxides (NOx) as the fuel is blended with up to 30% H2 by volume. The Caterpillar CG137-8 natural gas engine used for testing was originally designed for industrial gas compression applications and is a good representative for most “rich burn” engines used across industry for applications such as power generation, gas compression, and water pumping. A significant greenhouse gas (GHG) emissions reduction is observed as more H2 is added to the fuel. Increasing H2 in the fuel changes combustion behavior in the cylinder, resulting in faster ignition and higher cylinder pressures, which increase engine-out NOx emissions. Post-catalyst CO and NOx both decrease slightly with increasing H2 while operating at the optimal “air-fuel” equivalence ratio (λ). A “rich burn” engine with 3-way catalyst can tolerate up to 30% H2 (by vol.) while still meeting NOx and CO emissions limits. However, at elevated levels of H2, increased engine-out NOx emissions narrow the λ range of operation. As H2 is added to NG pipelines, some “rich burn” engine systems may require larger catalysts or more precise λ control to accommodate the increased NOx production associated with a H2-NG blend. Sudden step-increases in H2 cause dramatic changes in λ, resulting in large emissions of post-catalyst NOx during the transition. Comparable changes in H2 at elevated concentrations cause larger spikes in NOx than at lower concentrations. Better tuned engine controllers respond more quickly and produce less NOx during H2 step-transitions.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2024.1404052</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2024.1404052</link>
        <title><![CDATA[A technology integration approach for optimising biohydrogen production from food waste]]></title>
        <pubdate>2024-08-21T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Cynthia Kusin Okoro-Shekwaga</author><author>Mark Wilmshurst</author>
        <description><![CDATA[Dark fermentation of food waste for biohydrogen production is a progressive technology that can contribute to low-cost solutions to the global clean energy need. As dark fermentation research progresses, it is important to evaluate opportunities for real-life application such as integration into existing anaerobic digestion systems. The present study proposes a novel approach of combined inoculum and food waste heat shock pretreatment for biohydrogen production through dark fermentation. It evaluates the effect of the heating duration (at 115°C) and starting pH on the biohydrogen yield and system profiles in two stages, namely, Exp1 and Exp2. Exp1 investigated the optimal heating duration and starting pH for a combined inoculum/food waste heat shock pretreatment. A 24-h biohydrogen production test at four heating durations (15, 30, 45 and 60 min) was assayed at acidic and alkaline pH ranges (4, 5, 6 and 8, 9, 10). The optimal starting pH from these experiments across all four heating durations was pH 5. Biohydrogen yield increased linearly from 37.4 to 63.8 mL/gVS, with an increase in heating duration from 15 to 60 min at pH 5. However, an optimal heating duration was not reached, therefore, additional tests were conducted at pH 5 for extended heating durations of 75–120 min. Biohydrogen yield was similar at 75, 90 and 105-min heating durations in a range of 69.7–73.5 mL/gVS. Above 105 min of heating duration, the overall gas production starts to decline, making it the maximum allowable heating duration. In Exp2, a comparative analysis of the system profiles between the combined inoculum/food waste pretreatment (Test) and inoculum-only pretreatment (Control) was investigated using the optimal heating duration range (75 and 105 min) and starting pH of 5. The peak biohydrogen yield from the Control was achieved following a 75-min heating duration (84.5 mL/gVS, 58.6%), while this was achieved following a 90-min heating duration for the Test (81.3 mL/gVS, 53.3%). Higher volatile fatty acids fermentation and pH recovery were achieved in the Test in addition to potential economic savings compared to the Control. Therefore, the innovative approach of combined food waste/inoculum heat shock pretreatment (Test) presents opportunities to integrate dark fermentation into existing anaerobic digestion systems as a step to scale up the dark fermentation technology from lab to real-life application.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/ffuel.2024.1397962</guid>
        <link>https://www.frontiersin.org/articles/10.3389/ffuel.2024.1397962</link>
        <title><![CDATA[Review of technological developments and LCA applications on biobased SAF conversion processes]]></title>
        <pubdate>2024-07-12T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Eleanor Borrill</author><author>S. C. Lenny Koh</author><author>Ruoyang Yuan</author>
        <description><![CDATA[The aviation industry, driven by evolving societal needs, faces rising demand post-Covid and increasing pressure to align with emission reduction targets, prompting the development of drop-in sustainable aviation fuels (SAF). Their compatibility with existing aircraft and infrastructure will help to implement these fuels with the urgency the global climate crisis requires. This review delves into the benefits and challenges of various feedstocks, addressing complexities in estimating feedstock availability by location. Identified research gaps include enhancing feedstock availability, yield, and diversity, investigating compositions, and implementing sustainable agricultural practices. A summary of ASTM-certified conversion processes and technical specifications is outlined, prompting further research into conversion efficiency, catalyst selectivity, blending limits, aromatic compounds, combustion instability, and numerical modeling. A summary of recent life cycle assessments (LCA) highlighted gaps in cradle-to-cradle assessments, location-specific analyses, temporal considerations, and broader environmental impact categories. Recommendations stress obtaining primary data for enhanced LCA accuracy, conducting more specialized and general LCA studies and combining LCA, techno-economic analysis, fuel requirements, and socio-political assessments in multi-criteria decision analysis. This paper underlines the pressing need for comprehensive research to inform SAF production alternatives in the context of global climate crisis mitigation.]]></description>
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