Publications

This article discusses the potential of using the double-Wiebe function to model combustion in a compression-ignition engine fueled by diesel fuel or its substitutes such as hydrotreated vegetable oil (HVO) and rapeseed methyl ester (RME) and hydrogen injected into the engine intake manifold. The hydrogen amount ranged from 0 to 35% of the total energy content of the fuels burned. It was found that co-combustion of liquid fuel with hydrogen is characterized by two distinct combustion phases: premixed and diffusion combustion. The premixed phase occurring just after ignition is characterized by a rapid combustion rate which increases with an increase in hydrogen injected. The novelty in this work is the modified formula for a double-Wiebe function and the proposed parameters of this function depending on the amount of hydrogen added for co-combustion with liquid fuel. To model this combustion process the modified double-Wiebe function was proposed which can model two phases with different combustion rates. For this purpose a normalized HRR was calculated and based on this curve coefficients for the double-Wiebe function were proposed. Satisfactory consistency with the experiment was achieved at a level determined by the coefficient of determination (R-squared) of above 0.98. It was concluded that the presented double-Wiebe function can be used to model combustion in 0-D and 1-D models for fuels: RME and HVO with hydrogen addition.

Contemporary research into decarbonized fuels such as H2/NH3 has highlighted complex challenges with applied combustion with marked changes in thermochemical properties leading to significant issues such as limited operational range flashback and instability particularly when attempts are made to optimize emissions production in conventional lean-premixed systems. Non-premixed configurations may address some of these issues but often lead to elevated NOx production particularly when ammonia is retained in the fuel mixture. Optimized fuel injection and blending strategies are essential to mitigate these challenges. This study investigates the application of a 75 %/25 %mol H2/NH3 blend in a swirl-stabilized combustor operated at elevated conditions of inlet temperature (500 K) and ambient pressure (0.11–0.6 MPa). A complex nonmonotonic relationship between swirl number and increasing ambient combustor pressure is demonstrated highlighting the intricate interplay between swirling flow structures and reaction kinetics which remains poorly understood. At medium swirl (SN = 0.8) an increase in pressure initially reduces NO emissions diminishing past ~0.3 MPa with an opposing trend evident for high swirl (SN = 2.0) as NO emissions fall rapidly when combustor pressure approaches 0.6 MPa. High-fidelity numerical modeling is presented to elucidate these interactions in detail. Numerical data generated using Detached Eddy Simulations (DES) were validated against experimental results to demonstrate a change in flame anchoring on the axial shear layer and marked change in recirculated flow structure successfully capturing the features of higher swirl number flows. Favorable comparisons are made with optical data and a reduction in NO emissions with increasing pressure is demonstrated to replicate changes to the swirling flame chemical kinetics. Findings provide valuable insights into the combustion behavior of hydrogen-rich ammonia flames contributing to the development of cleaner combustion technologies.

Energy transition is crucial for climate change mitigation and Sustainable Development Goals (SDGs) and has been a key government focus in Colombia since 2022 which must carefully consider its energy roadmap. This study evaluates three potential scenarios for achieving nearly 100% renewable energy by 2035: replacing fossil fuels with biofuels using hydrogen for transport and industrial heat and relying entirely on renewable electricity. This paper discusses these scenarios’ technical economic and social challenges including the need for substantial investments in renewable energy technologies and energy storage systems to replace fossil fuels. The discussion highlights the importance of balancing energy security environmental concerns and economic growth while addressing social priorities such as poverty eradication and access to healthcare and education. The results show that while the Colombian government’s energy transition goals are commendable a rapid energy transition requires 4 to 8 times the government’s projected 34 billion USD investment making it economically unfeasible. Notably focusing on wind photovoltaic and green hydrogen systems which need storage is too costly. Furthermore replacing fossil fuels in transport is impractical though increasing biofuel production could partially substitute fossil fuels. Less energy-intensive alternatives like trains and waterway transport should be considered to reduce energy demand and carbon footprint.

While renewable energy deployment has accelerated in recent years fossil fuels continue to play a dominant role in electricity generation worldwide. This necessitates the development of transitional strategies to mitigate greenhouse gas emissions from this sector while gradually reducing reliance on fossil fuels. This study investigates the potential of blending green hydrogen with natural gas as a transitional solution to decarbonize Jordan’s electricity sector. The research presents a comprehensive techno-economic and environmental assessment evaluating the compatibility of the Arab Gas Pipeline and major power plants with hydrogen–natural gas mixtures considering blending limits energy needs environmental impacts and economic feasibility under Jordan’s 2030 energy scenario. The findings reveal that hydrogen blending between 5 and 20 percent can be technically achieved without major infrastructure modifications. The total hydrogen demand is estimated at 24.75 million kilograms per year with a reduction of 152.7 thousand tons of carbon dioxide per annum. This requires 296980 cubic meters of water per year equivalent to only 0.1 percent of the National Water Carrier’s capacity indicating a negligible impact on national water resources. Although technically and environmentally feasible the project remains economically constrained requiring a carbon price of $1835.8 per ton of carbon dioxide for economic neutrality.

The urgent need to mitigate climate change has elevated green hydrogen as a sustainable alternative to fossil fuels while green cryptocurrencies have emerged to address the environmental concerns of traditional cryptocurrency mining. This study investigates the dynamic correlation between the green hydrogen market and selected green cryptocurrencies (Cardano Stellar Hedera Algorand and Chia) from July 2021 to April 2024 utilizing the Dynamic Conditional Correlation GARCH (DCC-GARCH) model with robustness checks using EGARCH and GJR-GARCH specifications. Our findings reveal significant correlations with peaks reaching up to 50% in 2022 a period likely influenced by the Russia-Ukraine conflict. Subsequently a decline in these correlations was observed in 2023. These results underscore the interconnectedness of sustainability-driven markets suggesting potential contagion effects during periods of global instability. The high persistence of correlation shocks (α + β values approaching unity) indicates that correlation regimes tend to be long- lasting with important implications for portfolio diversification and risk management strategies. Robustness checks using EGARCH and GJR-GARCH specifications confirmed qualitatively similar patterns reinforcing the validity of our findings into the evolving landscape of green finance and energy

The transport of natural gas blended with hydrogen is a key strategy for the low-carbon energy transition. However the influence mechanism of its thermo-physical property variations on centrifugal compressor performance remains insufficiently understood. This study systematically investigates the effects of the hydrogen blending ratio (HBR 0–30%) inlet temperature and rotational speed on key compressor parameters (pressure ratio polytropic efficiency and outlet temperature) through numerical simulations. In order to evaluate the influence of hydrogen blending on the performance and stability of centrifugal compressors a three-dimensional model of the compressor was established and the simulation conducted was verified with the experimental data. Results indicate that under constant inlet conditions both the pressure ratio and outlet temperature decrease with increasing HBR while polytropic efficiency remains relatively stable. Hydrogen blending significantly expands the surge margin shifting both surge and choke lines downward and consequently reducing the stable operating range by 27.11% when hydrogen content increases from 0% to 30%. This research provides theoretical foundations and practical guidance for optimizing hydrogen-blended natural gas centrifugal compressor design and operational control.

In light of increased international efforts to combat climate change sustainable infrastructure is shifting toward green hydrogen produced through renewable-powered electrolysis. Still it is challenging to forecast the production of green hydrogen because environmental and system factors are variable both in time and space. We introduce a new system that utilizes a Spatio-Temporal Graph Convolutional Network (STGCN) and a novel algorithm the Ninja Optimization Algorithm (NiOA) to address this issue. Using the framework binary NiOA performs feature selection while continuous NiOA optimizes both the model architecture and the number of variables in the data simultaneously. It is clear from the research that forecasting results have shown significant improvement. The STGCN model achieved an R2 of 0.8769 and an MSE of 0.00375 whereas the STGCN with NiOA reached an R2 of 0.9815 and an MSE of only 7.48 × 10−8. Due to these improvements adaptive metaheuristics show even greater promise in delivering more accurate forecasting and reduced computational requirements for addressing critical environmental issues. The suggested strategy can be followed repeatedly providing a solid framework for the effective modeling of renewable energy systems and making green hydrogen projects more dependable.

As hydrogen gains prominence in energy systems its adoption as an energy source for fuel cell electric vehicles (FCEVs) necessitates the establishment of hydrogen refueling stations (HRS). These stations contain critical compo-nents including nozzles storage tanks heat exchangers and compressors which must be certified by regulatory agen-cies to ensure safety and public trust. Current certification processes are fragmented and manually intensive creating inefficiencies and limiting transparency across the infrastructure lifecycle. In this paper we propose a blockchain-based solution that creates a secure and auditable network for certifying key HRS components. The system integrates an EVM-compatible blockchain decentralized storage and a modular suite of smart contracts (SCs) that formalize registration bidding accreditation certification and governance. Each contract encodes a distinct actor-driven work-flow enabling traceable and role-specific operations. A Decentralized Application (DApp) interface supports real-time and role-based interaction across the ecosystem. We present and evaluate the SCs and their underlying algorithms us-ing gas usage analysis load testing and security auditing. Load testing across the certification lifecycle shows stable transaction throughput and predictable cost profiles under increasing actor activity. A static security analysis con-firms resilience against common vulnerabilities. Our cost analysis indicates that while the framework is technically deployable on public blockchains the execution costs of certain functions make it more cost-effective for private blockchains or Layer 2 networks. We also compare our framework with existing systems to highlight its novelty and technical advantages. Our SCs DApp interface and load testing scripts are publicly available on GitHub.

Given the Kenyan challenges in energy availability accessibility and affordability exploring green hydrogen as a sustainable energy solution is supreme. This study aimed to assess the potential of green hydrogen production a transformative clean energy technology and its implications for Kenya's future energy. The specific objectives were to identify the drivers of change that could accelerate green hydrogen adoption and policy recommendations. The study employed a scenario planning approach focusing on four key steps: defining the scenario and time horizon identifying drivers of change and developing and applying scenarios. The diffusion of innovation theory guided the study. Twelve key critical drivers of change were identified with societal and industry acceptance of green hydrogen and compatibility with existing energy infrastructure being the strongest drivers of change from cross-impact analysis results. The study outlined four plausible future scenarios for adoption: Successful Production (best scenario) Low Production Chaotic Transition and Rejection of Green Hydrogen Production (worst scenario). Major opportunities include advancements in hydrogen production export potential and job creation. Cost competitiveness analysis is essential comparing Kenya's hydrogen with traditional fuels and African peers. Economic models suggest that Kenya's renewable energy can lower costs enhancing its position in clean energy innovation. However critical challenges involve regulatory uncertainty ethical concerns public misconceptions about green hydrogen safety and financial barriers due to high initial investment costs. The study recommended that the Kenyan government invest in renewable energy infrastructure formulate a comprehensive national hydrogen policy and establish an enabling environment to attract private investment. In conclusion green hydrogen production stands as a strategic pillar for Kenya’s sustainable energy transition and further research should focus on strengthening regulatory frameworks and enhancing public engagement to unlock its full potential.

Hydrogen will play a critical role in decarbonizing diverse economic sectors. However given limited sustainable resources and the energy-intensive nature of its production prioritizing its applications will be essential. Here we analyse approximately 2000 (low-carbon) hydrogen projects worldwide encompassing operational and planned initiatives until 2043 quantifying their greenhouse gas (GHG) emissions and mitigation potential from a life cycle perspective. Our results demonstrate the variability in GHG emissions of hydrogen applications depending on the geographical location and hydrogen source used. The most climate-effective hydrogen applications include steel-making biofuels and ammonia while hydrogen use for road transport power generation and domestic heating should be discouraged as more favourable alternatives exist. Planned low-carbon hydrogen projects could generate 110 MtH2 yr−1 emit approximately 0.4 GtCO2e yr−1 and potentially reduce net life cycle GHG emissions by 0.2–1.1 GtCO2e yr−1 by 2043 depending on the substituted product or service. Addressing the current hydrogen implementation gap and prioritizing climate-effective applications are crucial for meeting decarbonization goals.

Hydrogen-based fuels are potential candidates to help international shipping achieve net-zero greenhouse gas (GHG) emissions by around 2050. This paper quantifies the environmental impacts of liquid hydrogen liquid ammonia and methanol used in a Post-Panamax container ship from 2020 to 2050. It considers cargo capacity changes electricity decarbonization and hydrogen production transitions under two International Energy Agency scenarios: the Stated Policies Scenario (STEPS) and the Net Zero Emissions by 2050 Scenario (NZE). Results show that compared to the existing HFO ship hydrogen-based propulsion systems can decrease cargo weight capacity by 0.3 % to 25 %. In the NZE scenario hydrogen-based fuels can reduce GHG emissions per tonne-nautical mile by 48 %–65 % compared to heavy fuel oil by 2050. Even with fully renewable hydrogenbased fuels 18 %–31 % of GHG emissions would still remain. Using hydrogen-based fuels in internal combustion engines requires attention to minimize environmental trade-offs.

Global renewable hydrogen trade is expected to play a key role in decarbonizing future energy systems. Yet hydrogen exporters may deviate from perfectly competitive behaviour to influence prices similarly to the existing fossil fuel market with important implications for consumer welfare and the pace of the energy transition. This study develops a global renewable hydrogen trade model that captures potential strategic interactions among exporters using a Stackelberg game-theoretic framework. The model is formulated as an Equilibrium Problem with Equilibrium Constraints (EPEC) and solved under three alternative equilibria: a profitmaximizing Nash equilibrium a cost-minimizing Nash equilibrium and a welfare-maximizing benchmark representing perfect competition. Results indicate that producers may strategically reduce their export quantities by up to 40 % relative to perfect competition to maximize profits. Such behaviour raises prices to a minimum of 4.5 USD/kg in 2050 across major import markets thereby significantly eroding consumer surplus. Strategic behaviour of dominant exporters also shifts trade flows reshaping the global allocation of hydrogen supply. Sensitivity analysis further reveals that financing costs play a key role in shaping strategic producers’ behaviour with lower financing costs helping to reduce prices and stimulate demand. These findings highlight the implications of imperfect competition in global hydrogen trade and suggest that policy measures may be needed to mitigate potential negative consequences.

This study investigates the cost-optimal capacity and operation of water electrolyzers in global net-zero CO2 energy systems. The production costs of hydrogen are largely determined by the electrolyzer capacity factor (i.e. full-load hours); therefore a global energy system model with an hourly temporal resolution was employed to consider the intermittency of variable renewable energy (VRE) and the dynamics of power system operations. Proton exchange membrane electrolysis is assumed in this study. The optimization results suggest three main findings. First water electrolysis is estimated to be a cost-effective option for achieving net-zero CO2 emissions. Under default technology assumptions the global installed capacity is projected to reach 2719 GW by 2050 with the majority of hydrogen consumed in the industry sector. Scaling up the supply chain is essential to realize this pathway. Second hydrogen and hydrogen-based fuels are economically competitive with negative emission technologies (NETs). A modest deployment of CO2 storage and NETs provides favorable conditions for water electrolysis deployment—and vice versa. Third flexible operation is critical to the widespread deployment of water electrolysis. In the default case the global weighted average capacity factor of electrolyzers is estimated at 37 % in 2050 to follow VRE output fluctuations. The results also indicate that limited operational flexibility may significantly hinder the cost-competitiveness of electrolyzer deployment.

In 2023 global carbon dioxide emissions reached 40 billion tonnes 60 % more than in 1990 intensifying climate concerns. This study explores hydrogen-natural gas blending as a transitional strategy for decarbonization across several regions and energy sectors – residential commercial industrial and agricultural. A multi-regional analysis framework evaluates integration of 20 % by volume low-carbon hydrogen blending into natural gas systems by identifying hydrogen producers importers and exporters based on production and import costs. Applied to Canada 528 scenarios (2026–2050) assess inter-regional hydrogen trade within Canadian provinces. The lowest-cost scenario involves Alberta exporting hydrogen produced through autothermal reforming with 91 % carbon capture and storage and British Columbia producing its own. The grid electrolysis scenario achieves the highest GHG reductions with a 4.5 % GHG mitigation in Canada with full energy system representation. These findings provide insights for policymakers and stakeholders in advancing hydrogen infrastructure and decarbonization strategies.

Fluidized bed systems play a crucial role in industrial processes such as combustion and gasification. In the Iron Power Cycle fluidized bed systems are essential for enabling the reduction of combusted iron back to iron making them a critical component in the regeneration step of the cycle. This study investigates the impact of operating gas velocity on conversion by performing reduction experiments at three distinct fluidization numbers (us/umf): 16 (bubbling regime) 55 (transition region) and 100 (fully turbulent regime). Experiments were conducted to determine the appropriate velocities for each regime ensuring optimal fluidization conditions across reduction temperatures ranging from 500 to 700 ⚬C. The results reveal that conversion rates increase significantly with gas velocities. At 500 ⚬C operating at approximately six times higher velocity leads to a sixfold improvement in conversion when using iron-oxide particles with a Sauter mean diameter of 61 µm. However while enhanced velocities improve reaction efficiency challenges remain at elevated temperatures (T ≥ 500 ⚬C) where iron undergoes defluidization when exposed to hydrogen. Once defluidization occurs refluidization proves impossible with either hydrogen or nitrogen raising concerns about process stability. These insights highlight the potential for optimizing fluidized bed reduction through velocity control while also underscoring the need for additional measures to mitigate unstable fluidization during high-temperature iron oxide reduction.

Dating back to more than one century ago the photocatalysis process has demonstrated great promise in addressing environmental problems and the energy crisis. Nevertheless some single or binary composite materials cannot meet the requirements of large-scale implementations owing to their limited photocatalytic efficiencies. Since 2021 dual S-scheme heterojunctionbased nanocomposites have been undertaken as highly efficient photoactive materials for green energy production and environmental applications in order to overcome limitations faced in traditional photocatalysts. Herein state-of-the-art protocols designed for the synthesis of dual S-scheme heterojunctions are described. How the combined three semiconductors in dual S-scheme heterojunctions can benefit from one another to achieve high energy production and efficient oxidative removal of various pollutants is deeply explained. Photocatalytic reaction mechanisms by paying special attention to the creation of Fermi levels (Ef ) and charge carriers transfer between the three semiconductors in dual S-scheme heterojunctions are discussed. An entire section has been dedicated to some examples of preparation and applications of double S-scheme heterojunction-based nanocomposites for several photocatalytic applications such as soluble pollutants photodegradation bacteria disinfection artificial photosynthesis H2 generation H2O2 production CO2 reduction and ammonia synthesis. Lastly the current challenges of dual S-scheme heterojunctions are presented and future research directions are presented. To sum up dual S-scheme heterojunction nanocomposites are promising photocatalytic materials in the pursuit of sustainable energy production and environmental remediation. In the future dual S-scheme heterojunctions are highly recommended for photoreactors engineering instead of single or binary photocatalysts to drive forward photocatalysis processes for practical green energy production and environmental protection.

Concerns about the competitiveness of European industry led to the publication of the Draghi report. One of his recommendations is to install regional green industrial clusters around energy-intensive companies. The report identifies three benefit categories each corresponding to typical industrial symbiosis cases: improved investment cases by shared local low-carbon energy generation improved investment cases by shared infrastructure and improved energy flows for increased resource efficiency. Industrial clusters hold untapped potential to advance the energy transition and climate neutrality. However it is still unknown how and if this potential will ever be reached nor how scalable and replicable the benefits will be. This review paper aims to take a first step in exploring the potential role of industrial clusters in the energy system by exposing the research state of the art in academic literature. A literature review is performed in line with the three benefit categories according to Draghi to understand the enablers and barriers of potential synergies and their impact on the energy system. Afterwards the scalability is assessed by positioning the European industrial clusters in the larger renewable energy landscape. To illustrate the global interest a brief reflection is made on references to industrial clusters in the policy of non-European regions. The work concludes with interesting leads for future research to further advance knowledge on the importance of industrial clusters in the energy system and to stimulate the implementation of energy synergies.

This paper investigates the performance and economic viability of Combined Cycle Gas Turbines (CCGT) operating on natural gas (NG) and hydrogen within the context of evolving electricity markets. The study is structured into several sections beginning with a benchmark analysis to establish baseline performance metrics including break-even prices and price margins for CCGTs running on NG. The research then explores various base cases and sensitivity analyses focusing on different CCGT capacity factors and the uncertainties surrounding key parameters. The study also compares the performance of CCGTs across different European countries highlighting the impact of increased price fluctuations in forecasted electricity markets. Additionally the paper examines Power-to-X-to-Power (P2X2P) configurations assessing the economic feasibility of hydrogen production and its integration into CCGT operations. The analysis considers scenarios where hydrogen is sourced externally or produced on-site using renewable energy or grid electricity during off-peak hours. The results provide insights into the competitiveness and adaptability of CCGTs in a transitioning energy landscape emphasizing the potential role of hydrogen as a flexible and sustainable energy carrier.

This study presents a comprehensive framework that integrates high-resolution energy forecasting and technoeconomic modeling to assess green hydrogen production potential in Flanders Belgium. Using 15-min interval data from the Elia Group four deep learning models (LSTM BiLSTM GRU and CNN-LSTM) were developed to forecast regional photovoltaic (PV) and onshore wind energy generation. These forecasts informed the estimation of hydrogen yields and the evaluation of the levelized cost of hydrogen (LCOH) under different configurations. Results show that wind-powered hydrogen production achieves the lowest LCOH (6.63 €/kg) due to higher annual operating hours. Among electrolysis technologies alkaline electrolysis (AEL) offers the lowest cost while proton exchange membrane (PEMEL) provides greater flexibility for intermittent power sources. The hybrid PVwind system demonstrated seasonal complementarity increasing annual hydrogen yield and improving production stability. The proposed framework supports regional planning and highlights strategic investment opportunities for cost-effective green hydrogen deployment.

A potential strategy to promote the use of clean energy is the development of catalyst-coated cathodic electrodes that are economical effective and sustainable to enhance the generation of hydrogen (H2) through the electrolysis process. This study investigates the unique design and use of stainless steel (SS) coated with a CuNiZnFeOx catalyst as both anode and cathode electrodes in the alkaline electrolysis process. The electrode exhibits an improved electrochemical behavior achieving a current density of 92 mA/cm2 at an applied voltage of 2.5 V with a surface area of 36 cm2 in 1 M KOH electrolyte at 25 ◦C. Furthermore the H2 production is systematically investigated by varying electrolyte concentration applied voltage and temperature. The results demonstrate that H2 production increases significantly with enhanced electrolyte concentration (3102 mL at 2 M KOH) applied voltage (3468 mL at 3.0 V) and temperature (3202 mL at 60 ◦C) over a 300 min electrolysis time. However optimal operating conditions are determined to be 1 M KOH 2.5 V and 25 ◦C balancing performance and energy efficiency. The improved performance is primarily attributed to enhanced ionic conductivity reduced internal resistance and the synergistic catalytic activity of the Cu-integrated NiZnFeOx coating.

Hydrogen plays a central role in ensuring the fulfillment of the climate and energy goals established in the Paris Agreement. To implement sustainable and resilient hydrogen economies it is essential to analyze the entire hydrogen value chain following a Life Cycle Assessment (LCA) methodology. To determine the current methodologies approaches and research tendencies adopted when performing LCA of hydrogen energy systems a systematic literature analysis is carried out in the present study. The choices regarding the “goal and scope definition” “life cycle inventory analysis” and “life cycle impact assessment” in 70 scientific papers were assessed. Based on the collected information it was concluded that there are no similar LCA studies since specificities introduced in the system boundaries functional unit production storage transportation end-use technologies geographical specifications and LCA methodological approaches among others introduce differences among studies. This lack of harmonization triggers the need to define harmonization protocols that allow for a fair comparison between studies; otherwise the decision-making process in the hydrogen energy sector may be influenced by methodological choices. Although initial efforts have been made their adoption remains limited and greater promotion is needed to encourage wider implementation.

The growing demand for air connectivity coupled with the forecasted increase in passengers by 2040 implies an exigency in the aviation sector to adopt sustainable approaches for net zero emission by 2050. Sustainable Aviation Fuel (SAF) is currently the most promising short-term solution; however ensuring its overall sustainability depends on reducing the life cycle carbon footprints. A key challenge prevails in hydrogen usage as a reactant for the approved ASTM routes of SAF. The processing conversion and refinement of feed entailing hydrodeoxygenation (HDO) decarboxylation hydrogenation isomerisation and hydrocracking requires substantial hydrogen input. This hydrogen is sourced either in situ or ex situ with the supply chain encompassing renewables or non-renewables origins. Addressing this hydrogen usage and recognising the emission implications thereof has therefore become a novel research priority. Aside from the preferred adoption of renewable water electrolysis to generate hydrogen other promising pathways encompass hydrothermal gasification biomass gasification (with or without carbon capture) and biomethane with steam methane reforming (with or without carbon capture) owing to the lower greenhouse emissions the convincing status of the technology readiness level and the lower acidification potential. Equally imperative are measures for reducing hydrogen demand in SAF pathways. Strategies involve identifying the appropriate catalyst (monometallic and bimetallic sulphide catalyst) increasing the catalyst life in the deoxygenation process deploying low-cost iso-propanol (hydrogen donor) developing the aerobic fermentation of sugar to 14 dimethyl cyclooctane with the intermediate formation of isoprene and advancing aqueous phase reforming or single-stage hydro processing. Other supportive alternatives include implementing the catalytic and co-pyrolysis of waste oil with solid feedstocks and selecting highly saturated feedstock. Thus future progress demands coordinated innovation and research endeavours to bolster the seamless integration of the cutting-edge hydrogen production processes with the SAF infrastructure. Rigorous technoeconomic and life cycle assessments alongside technological breakthroughs and biomass characterisation are indispensable for ensuring scalability and sustainability

This work develops a replicable method for designing the optimal renewable hydrogen production facility applicable to any site and based on technical parameters and actual equipment costs. The solution is based on the integration of photovoltaic (PV) energy with lithium-ion battery storage systems which maximizes electrolyzer operating hours and significantly reduces the Levelized Cost of Hydrogen (LCOH). This study shows that increasing the inclination of the photovoltaic modules reduces the need for storage optimizing operation and extending the electrolyzer’s annual operating hours. In the Seville case study with current costs and efficiencies a minimum LCOH of €4.43/kg was achieved a value well below market benchmarks opening the door to a potentially competitive industrial business. The analysis confirms that electrolyzer efficiency—particularly specific power consumption—is the most important factor in reducing costs while technological progress in photovoltaics storage and equipment promises further reductions in the coming years. Overall the proposed methodology offers a practical and scalable tool to accelerate the economic viability of green hydrogen in a variety of contexts.

The increasing global demand for clean energy highlights hydrogen as a strategic energy carrier due to its high energy density and carbon-free utilization. Currently steam methane reforming (SMR) is the most widely applied method for hydrogen production; however its high CO2 emissions undermine the environmental benefits of hydrogen. Blue hydrogen production integrates carbon capture and storage (CCS) technologies to overcome this drawback in the SMR process significantly reducing greenhouse gas emissions. This study integrated a MATLAB-R2025b-based plug flow reactor (PFR) model for SMR kinetics with an Aspen HYSYS-based CCS system. The effects of reformer temperature (600–1000 ◦C) and steam-to-carbon (S/C) ratio (1–5) on hydrogen yield and CO2 emission intensity were investigated. Results show that hydrogen production increases with temperature reaching maximum conversion at 850–1000 ◦C while the optimum performance is achieved at S/C ratios of 2.5–3.0 balancing high hydrogen yield and minimized methane slip. Conventional SMR generates 9–12 kgCO2/kgH2 emissions whereas SMR + CCS reduces this to 2–3 kgCO2/kgH2 achieving more than 75% reduction. The findings demonstrate that SMR + CCS integration effectively mitigates emissions and provides a sustainable bridging technology for blue hydrogen production supporting the transition toward lowcarbon energy systems.

The paper studies and analyzes electric vehicle engines powered by hydrogen under the WLTP standard driving protocol. The driving range extension is estimated using a specific protocol developed for FCEV compared with the standard value for battery electric vehicles. The driving range is extended by 10 km averaging over the four protocols with a maximum of 11.6 km for the FTP-75 and a minimum of 7.7 km for the WLTP. This driving range extension represents a 1.8% driving range improvement on average. Applying the FCEV current weight the driving range is extended to 18.9 km and 20.4 km on average when using power source energy capacity standards for BEVs and FCEVs.