Applications & Pathways

Ammonia is a particularly promising hydrogen carrier due to its relatively low cost high energy density its liquid storage and to its production from renewable sources. Thus in recent years great attention is devoted to this fuel for realizing next generation refueling stations according to a carbon-free energy economy. In this paper a distributed onsite refueling station (200 kg/day of hydrogen filling 700-bar HFCEVs (Hybrid Fuel Cell Electric Vehicles) with about 5 kg of hydrogen in 5 min) based on ammonia feeding is studied from the energy and economic point of views. The station is designed with a modular configuration consisting of more sections: i) the hydrogen production section ii) the electric energy supplier section iii) the compression and storage section and the refrigeration/dispenser section. The core of the station is the hydrogen production section that is based on an ammonia cracking reactor and its auxiliaries; the electric energy demand necessary for the station operation (i.e. the hydrogen compression and refrigeration) is satisfied by a PEMFC (Proton-Exchange Membrane Fuel Cell) power module. Energy performance according to the hydrogen daily demand has been evaluated and the estimation of the levelized cost of hydrogen (LCOH) has been carried out in order to establish the cost of the hydrogen at the pump that can assure the feasibility of this novel refueling station.

Hydrogen is a promising fuel to decarbonise aviation. Storage in liquid form is favoured for long-haul aircraft; storage as a high-pressure gas is preferred otherwise. The exergy expended during the compression or liquefaction process is stored as physical exergy in the fuel. Most discussions around hydrogen-fuelled aviation ignore this very significant exergy content. When combusted in an engine the chemical energy of hydrogen can produce around 60 MJ of work per kg. The work that can be extracted from the physical exergy depends strongly on the method used. This paper presents an exergy analysis considering a range of storage conditions operating conditions and work-extraction methods. For reasonable gas-turbine operating conditions upwards of 16 MJ/kg might be extracted from compressed hydrogen (at 700 bar) and 30 MJ/kg from LH2. This additional work representing 25–50 % of the shaft work produced by combustion has been by and large neglected.

Stringent CO2 reduction targets and tightening emission regulations have intensified interest in hydrogen internal combustion engines (H2ICEs) as a clean and robust solution for the heavy-duty (HD) sector. This study experimentally compares port fuel injection (PFI) early low-pressure direct injection (LPDI) and late LPDI strategies on a single-cylinder HD H2ICE under steady-state medium and high loads. The injection timing and fuel pressure are varied to study the overall influences on a single-cylinder heavy-duty H2ICE. PFI and early LPDI deliver high charge homogeneity but reduced volumetric efficiency compared to late LPDI. At medium load all three strategies achieve ~41 % gross indicated thermal efficiency (gITE). Increasing LPDI pressure from 12.8 to 20 bar enhances mixture uniformity cutting BSNOx emissions by up to 75 %. At high load early LPDI reaches 41.7 % gITE with low NOx (0.72 g/kWh) while late LPDI benefits from reduced heat transfer loss and compression work achieving 42.4 % gITE. However late injection also increases BSNOx (9.3 g/kWh) unburnt H2 (435 ppm) and pressure rise rate (19.7 bar/◦CA). These results highlight LPDI’s potential for high efficiency with injection timing and pressure as key levers to balance emissions and performance.

Green hydrogen will play a crucial role in the future of emission reduction in air traffic in the long-term as it will completely eliminate CO2 emissions and significantly reduce other pollutants such as contrails and nitrogen oxides. Hydrogen offers a promising alternative to kerosene for short- and medium-haul flights particularly through direct combustion and hydrogen fuel cell technology in new aircraft concepts. Against the background of the immense capital-intensive infrastructure adjustments that are required at airports for this purpose and the simultaneously high future hydrogen demand for the shipping industry this paper analyses the emission savings potential in Europe if airports near seaports would switch to hydrogen-powered flight connections.

Maritime and aviation transport are widely recognised as sectors where reducing greenhouse gas emissions is particularly challenging due to their reliance on energy-dense fuels and the challenges associated with direct electrification. These sectors face increasing pressure to defossilise and reduce emissions in line with global climate goals while simultaneously facing unique technological operational and economic uncertainties. This study addresses a key research gap by comparing the maritime and aviation sectors for common factors and sector-specific differences in their transition to green e-fuels produced from renewable electricity and sustainable CO2. A techno-economic assessment is conducted to evaluate alternative fuel and propulsion options using the levelised cost of mobility framework. The analysis also incorporates the pricing of non-CO2 greenhouse gases and air pollutant emissions. Results show that e-ammonia or e-LNG combustion is the most cost-effective option for maritime transport when emission costs are excluded whereas hydrogen fuel cells become more economical when these costs are internalised. In aviation e-kerosene use in conventional aircraft presents the lowest costs regardless of the year or emission pricing. The findings highlight the importance of considering unique characteristics of each sector and tailored defossilisation and decarbonisation strategies that consider sector-specific constraints. To sustainably meet the growing demand for transport fuels rapid investments in renewable electricity generation electrolysers and e-fuel synthesis are essential. Development of strong regulatory frameworks and financial instruments will be critical to support early deployment of e-fuels and minimise the risks.

In Southern Italy near the Mediterranean Sea mobility services like cars bicycles scooters and materialhandling forklifts are frequently required in addition to multimodal local transportation services such as trains ferry boats and airplanes. This research proposes an innovative concept of hydrogen valley virtually simulated in Matlab/Simulink environment located in Calabria. As a novelty hydrogen is produced centrally and delivered via fuel cell hybrid trains to seven hydrogen refueling stations serving various mobility hubs. The centralized production facility operates with a nominal capacity of about 4 tons/day producing hydrogen via PEM electrolysis and storing hydrogen at 200 bar with a hydrogen compressor. As the size of vehicle fleets and the cost of acquiring renewable energy through power purchase agreements vary the hydrogen valley is examined from both a technical and an economic perspective analyzing: the values of the levelized cost of hydrogen the energy consumption and the energy efficiency of the energy systems. Specifically the levelized cost of hydrogen reached competitive values close to 5 €/kg of hydrogen under the most optimistic scenarios with fleet conversions of more than 60 % and a power purchase agreement price lower than 150 €/MWh. Then the benefits of hydrogen rail transport in terms of emissions reduction and health from an economic standpoint are compared to conventional diesel trains and fully electric trains saving respectively 3.2 ktons/year and 0.4 ktons/year of carbon dioxide equivalent emissions and corresponding economic benefits of respectively 51 and 0.548 million euros.

The use of aluminum-based products is widespread and growing particularly in industries such as automotive food packaging and construction. Obtaining aluminum is expensive and energy-intensive making the recycling of existing products essential for economic and environmental viability. This work explores the potential of using green hydrogen as a replacement for natural gas in the smelting and refining furnaces in aluminum recycling facilities. The adoption of green hydrogen has the potential to curtail approximately 4.54 Ktons/year of CO2 emissions rendering it a sustainable and economically advantageous solution. The work evaluates the economic viability of a case study through assessing the Net Present Value (NPV) and the Internal Rate of Return (IRR). Furthermore it is employed single- and multi-parameter sensitivity analyses to obtain insight on the most relevant conditions to achieve economic viability. Results demonstrate that integrating on-site green hydrogen generation yields a favorable NPV of €57370 an IRR of 9.83% and a 19.63-year payback period. The primary factors influencing NPV are the initial electricity consumption stack and the H2 price.

The integration of wind and solar energy with green hydrogen technologies represents an innovative approach toward achieving sustainable energy solutions. This review examines state-ofthe-art strategies for synthesizing renewable energy sources aimed at improving the efficiency of hydrogen (H2 ) generation storage and utilization. The complementary characteristics of solar and wind energy where solar power typically peaks during daylight hours while wind energy becomes more accessible at night or during overcast conditions facilitate more reliable and stable hydrogen production. Quantitatively hybrid systems can realize a reduction in the levelized cost of hydrogen (LCOH) ranging from EUR 3.5 to EUR 8.9 per kilogram thereby maximizing the use of renewable resources but also minimizing the overall H2 production and infrastructure costs. Furthermore advancements such as enhanced electrolysis technologies with overall efficiencies rising from 6% in 2008 to over 20% in the near future illustrate significant progress in this domain. The review also addresses operational challenges including intermittency and scalability and introduces system topologies that enhance both efficiency and performance. However it is essential to consider these challenges carefully because they can significantly impact the overall effectiveness of hydrogen production systems. By providing a comprehensive assessment of these hybrid systems (which are gaining traction) this study highlights their potential to address the increasing global energy demands. However it also aims to support the transition toward a carbon-neutral future. This potential is significant because it aligns with both environmental goals and energy requirements. Although challenges remain the promise of these systems is evident.

The use of hydrogen as a source of fuel for marine applications is relatively nascent. As the maritime industry pivots to the use of alternate low and zero-emission fuels to adapt to a changing regulatory landscape hydrogen energy needs to present and substantiate a technical and commercially viable use case to secure its value proposition in the future fuel mix. This paper leverages the technoeconomic and environmental assessment previously performed on HyForce a hydrogen-fuelled harbour tug which has shown encouraging results for both technical and commercial aspects. This study aims to create a digital twin of HyForce to accurately predict her operability in real-world scenarios. The results from this study identify the strengths and drawbacks of the proposed use case. This is achieved by embedding the detailed design of HyForce in a virtual environment to further evaluate its operational performance through Computational Fluid Dynamics (CFD) simulations of realistic environmental conditions such as wind wave sea currents and friction attributed to the properties of seawater. The results from this study indicate a base case power requirement of 93 kW to 1892 kW to achieve speeds of 5 to 12 knots in the absence of external environmental influences. Consequently the speed of HyForce has a profound impact on total resistance peaking at 97.3 kN at 12 knots. Seawater properties such as low seawater temperature of 0C and a high salinity of 50g/kg increased friction. Additionally wind speeds of 10 m/s acting on HyForce delivered a resistance of 3 kN. However these will be well mitigated through the design of the propulsion system which will be able to deliver a thrust power of 1892 kW and with assistance from the energy storage systems produce 2 MW of power to overcome the resistance experienced. The findings presented in this paper can serve as a foundation for constructing a robust model for the development of a predictive controller for future work. This controller has the potential to optimize the configuration of hydrogen and battery energy storage aligning with desired cost functions.

The decarbonization of industrial process heat is one of the bigger challenges of the global energy transition. Process heating accounts for about 20% of final energy demand in Germany and the situation is similar in other industrialized nations around the globe. Process heating is indispensable in the manufacturing processes of products and materials encountered every day ranging from food beverages paper and textiles to metals ceramics glass and cement. At the same time process heating is also responsible for significant greenhouse gas emissions as it is heavily dependent on fossil fuels such as natural gas and coal. Thus process heating needs to be decarbonized. This review article explores the challenges of decarbonizing industrial process heat and then discusses two of the most promising options the use of electric heating technologies and the substitution of fossil fuels with low-carbon hydrogen in more detail. Both energy carriers have their specific benefits and drawbacks that have to be considered in the context of industrial decarbonization but also in terms of necessary energy infrastructures. The focus is on high-temperature process heat (>400 ◦C) in energy-intensive basic materials industries with examples from the metal and glass industries. Given the heterogeneity of industrial process heating both electricity and hydrogen will likely be the most prominent energy carriers for decarbonized high-temperature process heat each with their respective advantages and disadvantages.

Solid oxide fuel cells (SOFC) have developed to a mature technology able to achieve electrical efficiencies beyond 60%. This makes them particularly suitable for off-grid applications where SOFCs can supply both electricity and heat at high efficiency. Concerns related to lifetime particularly when operated dynamically and the high investment cost are however still the main obstacles toward a widespread adoption of this technology. In this paper we propose a hybrid cogeneration system that attempts to overcome these limitations in which the SOFC mainly provides the baseload of the system. Introducing a purification unit allows the production and storage of pure hydrogen from the SOFC anode off-gas. The hydrogen can be stored and used in a proton exchange membrane fuel cell (PEMFC) during peak demands. The SOFC system is completed with a battery used during periods of high electricity production. We propose the use of a mixed integer-linear optimization framework for the sizing of the different components of the system and particularly for identifying the optimal trade-off between round-trip efficiency and investment cost of the battery-based and hydrogen-based storage systems. The proposed system is applied and optimized to two case studies: an off-grid dwelling and a cruise ship. The results show that if the SOFC is used as the main energy conversion technology of the system the use of hydrogen storage in combination with a PEMFC and a battery is more economically convenient compared to the use of the SOFC in stand-alone mode or of pure battery storage. The results show that the proposed hybrid storage solution makes it possible to reduce the investment cost of the system while maintaining the use of the SOFC as the main energy source of the system.

The increasing depletion of fossil fuels and their environmental impact have led to the development of fuel cell hybrid electric vehicles. By combining fuel cells with batteries these vehicles offer greater efficiency and zero emissions. However their energy management remains a challenge requiring advanced strategies. This paper presents a comparative study of two developed energy management strategies: a deterministic rule-based approach and a fuzzy logic approach. The proposed system consists of a proton exchange membrane fuel cell (PEMFC) as the primary energy source and a lithium-ion battery as the secondary source. A comprehensive model of the hybrid powertrain is developed to evaluate energy distribution and system behaviour. The control system includes a model predictive control (MPC) method for fuel cell current regulation and a PI controller to maintain DC bus voltage stability. The proposed strategies are evaluated under standard driving cycles (UDDS and NEDC) using a simulation in MATLAB/Simulink. Key performance indicators such as fuel efficiency hydrogen consumption battery state-of-charge and voltage stability are examined to assess the effectiveness of each approach. Simulation results demonstrate that the deterministic strategy offers a structured and computationally efficient solution while the fuzzy logic approach provides greater adaptability to dynamic driving conditions leading to improved overall energy efficiency. These findings highlight the critical role of advanced control strategies in improving FCHEV performance and offer valuable insights for future developments in hybrid-vehicle energy management.

This study investigates potential solutions for low-carbon power generation with hydrogen firing and carbon capture. Multi-dimensional system modeling was used to assess the effects on plant performance size and cost. The examined cycles include advanced dry- wet- bottoming- oxyfuel cycles with air-separation units and post-combustion carbon capture with exhaust gas recirculation. The results identify three distinct lowcarbon technology pathways. While conventional combined-cycle plants are suitable for hydrogen retrofits hydrogen firing (both blue and green) results in levelized costs of electricity 50%–300% higher than carbon capture solutions making carbon capture more attractive for long-term energy storage. When carbon capture is applied to conventional combined cycles they become suboptimal compared to alternative solutions. The intercooled-recuperated (ICR) gas turbine cycle integrated with post-combustion carbon capture offers superior performance: over 3% higher efficiency 12% lower capital costs and 70% smaller physical footprint compared to conventional combined cycles with carbon capture. The Allam cycle represents a third pathway achieving 100% CO2 capture with efficiency comparable to combined cycles at 90% capture. Gas separation units emerge as the dominant source of both capital costs and efficiency penalties across all carbon capture configurations representing the key area for future optimization to reduce overall electricity costs.

The global transport sector a significant contributor to energy consumption and greenhouse gas (GHG) emissions requires innovative solutions to meet sustainability goals. Artificial intelligence (AI) has emerged as a transformative technology offering opportunities to enhance energy efficiency and reduce GHG emissions in transport systems. This study provides a comprehensive review of AI’s role in optimizing vehicle energy management traffic flow and alternative fuel technologies such as hydrogen fuel cells and biofuels. It explores AI’s potential to drive advancements in electric and autonomous vehicles shared mobility and smart transportation systems. The economic analysis demonstrates the viability of AI-enhanced transport considering Total Cost of Ownership (TCO) and cost-benefit outcomes. However challenges such as data quality computational demands system integration and ethical concerns must be addressed to fully harness AI’s potential. The study also highlights the policy implications of AI adoption underscoring the need for supportive regulatory frameworks and energy policies that promote innovation while ensuring safety and fairness.

Accelerating the transition to a cleaner global energy system is essential for tackling the climate crisis and green hydrogen energy systems hold significant promise for integrating renewable energy sources. This paper offers a thorough evaluation of green hydrogen’s potential as a groundbreaking alternative to achieve near-zero greenhouse gas (GHG) emissions within a renewable energy framework. The paper explores current technological options and assesses the industry’s present status alongside future challenges. It also includes an economic analysis to gauge the feasibility of integrating green hydrogen providing a critical review of the current and future expectations for the levelized cost of hydrogen (LCOH). Depending on the geographic location and the technology employed the LCOH for green hydrogen can range from as low as EUR 1.12/kg to as high as EUR 16.06/kg. Nonetheless the findings suggest that green hydrogen could play a crucial role in reducing GHG emissions particularly in hard-to-decarbonize sectors. A target LCOH of approximately EUR 1/kg by 2050 seems attainable in some geographies. However there are still significant hurdles to overcome before green hydrogen can become a cost-competitive alternative. Key challenges include the need for further technological advancements and the establishment of hydrogen policies to achieve cost reductions in electrolyzers which are vital for green hydrogen production.

The Department of Energy’s (DOE) hydrogen and fuel cell activities are presented focussing on key targets and progress. Recent results on the cost durability and performance of fuel cells are discussed along with the status of hydrogen-related technologies and cross-cutting activities. DOE has deployed fuel cells in key early markets including backup power and forklifts. Recent analyses show that fuel cell electric vehicles (FCEVs) are among the most promising options to reduce greenhouse gas emissions and petroleum use. Preliminary analysis also indicates that the total cost of ownership of FCEVs will be comparable to other advanced vehicle and fuel options.

Energy decarbonisation is essential to achieve Net-Zero emissions goal by 2050. Consequently investments in alternative low-carbon pathways and energy carriers for the heat sector are required. In this study we propose an optimisation framework for the transition of heat sector in Great Britain focusing on hydrogen infrastructure decisions. A spatially-explicit mixed-integer linear programming (MILP) evolution model is developed to minimise the total system’s cost considering investment and operational decisions. The optimisation framework incorporates both long-term planning horizon of 5-year steps from 2035 to 2050 and typical days with hourly resolution. Aiming to alleviate the computational effort of such multiscale model two hierarchical solution approaches are suggested that result in computational time reduction. From the optimisation results it is shown that the installation of gas reforming hydrogen production technologies with CCS and biomass gasification with CCS can provide a cost-effective strategy achieving decarbonisation goal. What-if analysis is conducted to demonstrate further insights for future hydrogen infrastructure investments. Results indicate that as cost is highly dependent on natural gas price Water Electrolysis capacity increases significantly when gas price rises. Moreover the introduction of carbon tax policy can lead to lower CO2 net emissions.

The work carried out in this paper focused on “Machine learning models for the prediction of turbulent combustion speed for hydrogen-natural gas spark ignition engines”. The aim of this work is to develop and verify the ability of machine learning models to solve the problem of estimating the turbulent flame speed for a spark-ignition internal combustion engine operating with a hydrogen-natural gas mixture then evaluate the relevance of these models in relation to the usual approaches. The novelty of this work is the possibility of a direct calculation of turbulent combustion speed with a good precision using only machine learning model. The obtained models are also compared to each other by considering in turn as a comparison criterion: the precision of the result calculation time and the ability to assimilate original data (which has not undergone preprocessing). An important particularity of this work is that the input variables of the machine learning models were chosen among the variables directly measurable experimentally based on the opinion of experts in combustion in internal combustion engines and not on the usual approaches to dimensionality reduction on a dataset. The data used for this work was taken from a MINSEL 380 a 380-cc single-cylinder engine. The results show that all the machine learning models obtained are significantly faster than the usual approach and Random Forest (R2: R-squared = 0.9939 and RMSE: Root Mean Square Error = 0.4274) gives the best results. With a forecasting accuracy of over 90 % both approaches can make reasonable predictions for most industrial applications such as designing engine monitoring and control systems firefighting systems simulation and prototyping tools.

Nowadays several technologies based on powertrain electrification and the exploitation of hydrogen represent valuable options for decarbonizing the on-road public transport sector. The considered alternatives should exhibit an effective benchmark between CO2 reduction potential and production/operational costs. Conducting a comprehensive Total Cost of Ownership (TCO) analysis coupled with a thorough Life Cycle Assessment (LCA) is therefore crucial in shaping the future for cleaner urban mobility. From this perspective this study compares different powertrain configurations for a 12 m urban bus: a conventional diesel Internal Combustion Engine Vehicle (ICEV) a series hybrid diesel two hydrogen-based series hybrid vehicles: a Hydrogen Hybrid Electric Vehicle featuring an H2-ICE (H2-HEV) or a Fuel Cell Electric Vehicle (FCEV) and a Battery Electric Vehicle (BEV). Moreover a sensitivity analysis has been conducted on the carbon footprint for power generation considering also the marginal electricity mix. In addition prospective LCA and TCO elements are introduced by addressing future technological projections for the 2030 horizon. The research reveals that as of today the BEV and hydrogen-fueled vehicles have comparable environmental impacts when the marginal electricity mix is considered. The techno-economic analysis indicates that under current conditions FCEVs and H2-HEVs are not cost-effective for CO₂ reduction unless powered by renewable energy sources. However considering future technological advancements and market evolution FCEVs offer the most promising balance between economic and environmental benefits particularly if hydrogen prices reach €4 per kilogram. If hydrogen-powered vehicles remain a niche market BEVs will be the most viable option for decarbonizing the transport sector in most European countries.

Green hydrogen production and storage are vital in mitigating carbon emissions and sustainable transition. However the high investment cost and management requirements are the bottleneck of utilizing hybrid hydrogen-based systems in microgrids. Given the necessity of cost-effective and optimal design of these systems the present study examines techno-economic feasibility of integrating hybrid hydrogen-based systems into an outdoor test facility. With this perspective several solar-driven hybrid scenarios are introduced at two energy storage levels namely the battery and hydrogen energy storage systems including the high-pressure gaseous hydrogen and metal hydride storage tanks. Dynamic simulations are carried out to address subtle interactions in components of the hybrid system by establishing a TRNSYS model coupled to a Fortran code simulating the metal hydride storage system. The OpenStudio-EnergyPlus plugin is used to simulate the building load validate against experimental data according to the measured data and monitored operating conditions. Aimed at enabling efficient integration of energy storage systems a techno-enviro-economic optimization algorithm is developed to simultaneously minimize the levelized cost of the electricity and maximize the CO2 mitigation in each proposed hybrid scenario. The results indicate that integrating the gaseous hydrogen and metal hydride storages into the photovoltaic-alone scenario enhances 22.6% and 14.4% of the annual renewable factor. Accordingly the inclusion of battery system to these hybrid scenarios gives a 30.4% and 20.3 % boost to the renewable factor value respectively. Although the inclusion of battery energy storage into the hybrid systems increases the renewable factor the results imply that it reduces the hydrogen production rate via electrolysis. The optimized values of the levelized cost of electricity and CO2 emission for different scenarios vary in the range of 0.376–0.789 $/kWh and 6.57–9.75 ton respectively. The multi-criteria optimizations improve the levelized cost of electricity and CO2 emission by up to 46.2% and 11.3% with respect to their preliminary design.

This study investigates hydrogen (H2) as a supplementary fuel in heavy-duty diesel engines using pre-manifold injection. A H2-diesel dual-fuel (H2DF) system was implemented on a commercial class-8 heavy-duty diesel truck without modifying the original diesel injection system and engine control unit (ECU). Tests were conducted on a chassis dynamometer at engine speeds between 1000 and 1400 rpm with driver-demanded torques from 10 to 75%. The hydrogen energy fraction (HEF) was strategically controlled in the range between 10 and 30%. Overall CO2 reduction (comparable to the HEF level) was achieved with similar brake-specific energy consumption (BSEC) at all loads and speeds. To maintain the same shaft torque the driver-demanded torque was reduced in H2DF operation which resulted in a lower boost pressure. At higher loads engine-out BSNOx slightly decreased while BSCO and black carbon (BC) increased significantly due to lower oxygen concentration resulting from the lower boost pressure. At lower loads engine-out BSCO and BSBC decreased moderately while NO2/NO ratio increased substantially in H2DF operation. Deliberate air path and diesel injection control are expected to enable higher HEF and GHG reductions.

As a zero-emission fuel hydrogen provides a promising solution with significant potential to meet the increasing demand for clean energy alternatives. Hydrogen fueling stations are essential infrastructure for the commercialization of hydrogen fuel cells but the flammability of hydrogen poses safety challenges throughout its lifecycle. Past incidents highlight the need for robust risk assessments starting with comprehensive hazard identification and failure scenario analysis.<br/>This paper proposes using Multilevel Flow Modelling (MFM) a functional modeling method integrated with reasoning capability to support safety evaluations. MFM enables the structured representation of system functions and supports tasks such as fault diagnosis and hazard analysis. Previously applied in nuclear offshore and chemical systems MFM is here used to model a liquid hydrogen fueling station. This paper demonstrates that a developed MFM model identifies failure scenarios related to hydrogen leaks overpressure and operational reliability issues.<br/>This paper conducts a comparison between MFM and traditional methods FMEA and FTA and demonstrates MFM's strength in handling the key challenges rooted from complex failure interactions. Results suggest MFM is complementary to traditional methods and can enhance risk assessments. MFM also contributes to digitalization in safety assessment and monitoring systems ultimately improving hydrogen fueling station reliability and safety.

In the future steel products will be reheated for hot working using hydrogen instead of natural gas. This study investigated the differences in oxide scale formation between natural gas/air and hydrogen/air combustion at constant air-fuel-ratio. Samples of a hypo-eutectoid eutectoid and hyper-eutectoid steel grade (dimensions: 30 x 30 x 50 mm W x H x L) were exposed to the two atmospheres in a semi-industrial scale furnace for 180 min at three sample core temperatures (1100 1200 and 1280 °C). Specific mass gain was calculated and the samples were metallographically examined. Switching the fuel increased scale formation depending on the steel. The exponential correlation between temperature and scale formation is more pronounced for the eutectoid and the hyper-eutectoid steel grade. Metallographic investigations revealed similar scale morphologies in both atmospheres but with significant temperature dependence. The decarburization depth is atmosphere-independent. Thus switching fuel does not negatively impact the properties of the steel substrate; it only increases scale formation during reheating.

An analysis of the turbulent premixed combustion speed in an internal combustion engine using natural gas hydrogen and intermediate mixtures as fuels is carried out with different air-fuel ratios and engine speeds. The combustion speed has been calculated by means of a two-zone diagnosis thermodynamic model combined with a geometric model using a spherical flame front hypothesis. 48 operating conditions have been analyzed. At each test point the pressure record of 200 cycles has been processed to calculate the cycle averaged turbulent combustion speed for each flame front radius. An expression of turbulent combustion speed has been established as a function of two parameters: the ratio between turbulence intensity and laminar combustion speed and the second parameter the ratio between the integral spatial scale and the thickness of the laminar flame front increased by instabilities. The conclusion of this initial study is that the position of the flame front has a great influence on the expression to calculate the combustion speed. A unified correlation for all positions of the flame front has been obtained by adding one correction term based on the expansion speed as a turbulence source. This unified correlation is thus valid for all experimental conditions of fuel types air–fuel ratios engine speeds and flame front positions. The correlation can be used in quasi-dimensional predictive models to determine the heat released in an ICE.

This study investigated the cost competitiveness using total cost of ownership (TCO) analysis of hydrogen fuel cell electric vehicles (FCEVs) in heavy duty on and off-road fleet applications as a key enabler in the decarbonisation of the transport sector and compares results to battery electric vehicles (BEVs) and diesel internal combustion engine vehicles (ICEVs). Assessments were carried out for a present day (2021) scenario and a sensitivity analysis assesses the impact of changing input parameters on FCEV TCO. This identified conditions under which FCEVs become competitive. A future outlook is also carried out examining the impact of time-sensitive parameters on TCO when net zero targets are to be reached in the UK and EU. Several FCEVs are cost competitive with ICEVs in 2021 but not BEVs under base case conditions. However FCEVs do have potential to become competitive with BEVs under specific conditions favouring hydrogen including the application of purchase grants and a reduced hydrogen price. By 2050 a number of FCEVs running on several hydrogen scenarios show a TCO lower than ICEVs and BEVs using rapid chargers but for the majority of vehicles considered BEVs remain the lowest in cost unless specific FCEV incentives are implemented. This paper has identified key factors hindering the deployment of hydrogen and conducted comprehensive TCO analysis in heavy duty on and off-road fleet applications. The output has direct contribution to the decarbonisation of the transport sector.

This study aimed to compare hydrogen ammonia methanol and waste-derived biofuels as shipping fuels using life cycle assessment to establish what potential they have to contribute to the shipping industry’s 100% greenhouse gas emission reduction target. A novel approach was taken where the greenhouse gas emissions associated with one year of global shipping fleet operations was used as a common unit for comparison therefore allowing the potential life cycle greenhouse gas emission reduction from each fuel option to be compared relative to Paris Agreement compliant targets for international shipping. The analysis uses life cycle assessment from resource extraction to use within ships with all GHGs evaluated for a 100-year time horizon (GWP100). Green hydrogen waste-derived biodiesel and bio-methanol are found to have the best decarbonisation po tential with potential emission reductions of 74–81% 87% and 85–94% compared to heavy fuel oil; however some barriers to shipping’s decarbonisation progress are identified. None of the alternative fuels considered are currently produced at a large enough scale to meet shipping’s current energy demand and uptake of alternative fuel vessels is too slow considering the scale of the challenge at hand. The decarbonisation potential from alternative fuels alone is also found to be insufficient as no fuel option can offer the 100% emission reduction required by the sector by 2050. The study also uncovers several sensitives within the life cycles of the fuel options analysed that have received limited attention in previous life cycle investigations into alternative shipping fuels. First the choice of allocation method can potentially double the life cycle greenhouse gas emissions of e-methanol due to the carbon ac counting challenges of using waste carbon dioxide streams during fuel production. This leads to concerns related to the true impact of using carbon dioxide captured from fossil-fuelled processes to produce a combustible product due to the resultant high downstream emissions. Second nitrous oxide emissions from ammonia combustion are found to be highly sensitive due to high greenhouse gas potency potentially offsetting any greenhouse reduction potential compared to heavy fuel oil. Further uncertainties are highlighted due to limited available data on the rate of nitrous oxide production from ammonia engines. The study therefore highlights an urgent need for the shipping sector to consider these factors when investing in new ammonia and methanol engines; failing to do so risks jeopardizing the sector’s progress towards decarbonisation. Finally whilst alternative fuels can offer good decarbonisation potential (particularly waste derived biomethanol and bio-diesel and green hydrogen) this cannot be achieved without accelerated investment in new and retrofit vessels and new fuel supply chains: the research concludes that existing pipeline of vessel orders and fuel production facilities is insufficient. Furthermore there is a need to integrate alternative fuel uptake with other decarbonisation strategies such as slow steaming and wind propulsion.

With the escalating global energy demand the pursuit of sustainable energy sources has become increasingly urgent. Among these biofuels have gained significant attention for their potential to provide renewable and eco-friendly alternatives. Biodiesel is recognized for its diverse and cost-effective feedstock options. The study provides a novel approach to the production of biodiesel by employing the use of Dunaliella salina microalgae as a green source. The research suggests the blends provide a future solution to less toxic fuel sources achieving efficiency and minimizing emissions. This research emphasize on the production of biodiesel from Dunaliella salina microalgae a promising resource due to its high energy yield. The microalgae were cultivated in an f/2 nutrient medium enriched with carbon dioxide vitamins and trace metals. A total of 700 mL of bio-oil was extracted using ultrasonication at 50 Hz for 85 minutes. Then the bio-oil was transesterified in a single-stage sodium hydroxide-catalysed process with methanol as a solvent. The process yielded a high extraction efficiency of 94%. The produced biodiesel was characterized through advanced analytical techniques including NMR spectroscopy GC-MS and FTIR test studies confirming its suitability as a fuel. Combustion and emission analyses revealed that the direct substitution of biodiesel blends for diesel in engines significantly reduced hydrocarbon and carbon monoxide emissions although a slight increase in nitrogen oxide (NOx) emissions was noted. The combustion and emission characteristics were influenced by blend composition and calorific value. Additionally the study provides a detailed comparison of the performance of pure diesel biodiesel blends and hydrogen-enriched biodiesel in diesel engines offering valuable insights into their environmental and performance impacts. This study gives additional insights towards future work such as scalability (consisting large scale cultivation of algae for better studies) engine durability (studies on engine wear and tear) and integration with renewable energy sources (integrating renewable sources like solar and wind energies).

As a subdivision of the hydrogen energy application field ship-borne hydrogen fuel cell systems have certain differences from vehicle or other application scenarios in terms of their structural type safety environmental adaptability and test verification. The connection method of the ship-borne hydrogen storage cylinder (SHSC) is very important for the hydrogen fuel cell ship and the structural parameters of the SHSC are particularly important in the hydrogen refueling process. To ensure the safe and reliable operation of the hydrogen-powered ship research on the filling of the SHSC under different connection modes was carried out during refueling. In our study a thermal flow physical model of the SHSC was established to research the hydrogen refueling process of the series and parallel SHSCs. The influence of series and parallel modes of the SHSCs on the hydrogen refueling process was explored and the evolution law of the internal flow field pressure and temperature of series and parallel SHSCs under different filling parameters was analyzed by numerical simulation. Our results confirmed the superiority of the parallel modular approach in terms of thermal safety during refueling. The results can supply a technical basis for the future development of hydrogen refueling stations and ship-board hydrogenation control algorithms.

The maritime industry while indispensable to global trade is a significant contributor to greenhouse gas (GHG) emissions accounting for approximately 3% of global emissions. As international regulatory bodies particularly the International Maritime Organization (IMO) push for ambitious decarbonization targets hydrogen-based technologies have emerged as promising alternatives to conventional fossil fuels. This review critically examines the potential of hydrogen fuels—including hydrogen fuel cells (HFCs) and hydrogen internal combustion engines (H2ICEs)—for maritime applications. It provides a comprehensive analysis of hydrogen production methods storage technologies onboard propulsion systems and the associated techno-economic and regulatory challenges. A detailed life cycle assessment (LCA) compares the environmental impacts of hydrogenpowered vessels with conventional diesel engines revealing significant benefits particularly when green or blue hydrogen sources are utilized. Despite notable hurdles—such as high production and retrofitting costs storage limitations and infrastructure gaps—hydrogen holds considerable promise in aligning maritime operations with global sustainability goals. The study underscores the importance of coordinated government policies technological innovation and international collaboration to realize hydrogen’s potential in decarbonizing the marine sector.

BACKGROUND: Norway is facing the challenge of reducing transport emissions. High speed crafts(HSC) are the means of transport with highest emissions. Currently there is little literature or experienceof using hydrogen systems for HSC.OBJECTIVE: Evaluate the economic feasibility of fuel cell (FC) powered HSC vs diesel and biodieseltoday and in a future scenario based on real world operation profile.<br/>METHOD: Historical AIS position data from the route combined with the speed-power characteristicsof a concept vessel was used to identify the energy and power demand. From the resulting data a suitableFC system was defined and an economic comparison made based on annual costs including annualizedinvestment and operational costs.<br/>RESULTS: HSC with a FC-system has an annual cost of 12.6 MNOK. It is 28% and 12% more expensivethan diesel and biodiesel alternative respectively. A sensitivity analysis with respect to 7 key design pa-rameters indicates that highest impact is made by hull energy efficiency FC system cost and hydrogen fuelcost. In a future scenario (2025–2030) with moderate technology improvements and cost developmentthe HSC with FC-systems can become competitive with diesel and cheaper than biodiesel.<br/>CONCLUSIONS: HSC with FC-systems may reach cost parity with conventional diesel in the period2025–2030.

China’s progress in decarbonizing its transportation particularly vehicle electrification is notable. However the economically effective pathways are underexplored. To find out how much cost is necessary for carbon neutrality for the light-duty vehicle (LDV) sector this study examines twenty decarbonization pathways combining the New Energy and Oil Consumption Credit model and the China-Fleet model. We find that the 2060 zero-greenhouse gas (GHG) emission goal for LDVs is achievable via electrification if the battery pack cost is under CNY483/kWh by 2050. However an extra of CNY8.86 trillion internal subsidies is needed under pessimistic battery cost scenarios (CNY759/kWh in 2050) to eliminate 246 million tonnes of CO2-eq by 2050 ensuring over 80% market penetration of battery electric vehicles (BEVs) in 2050. Moreover the promotion of fuel cell electric vehicles is synergy with BEVs to mitigate the carbon abatement difficulties decreasing up to 34% of the maximum marginal abatement internal investment.

As an energy-intensive sector China’s iron and steel industry is crucial for achieving “Dual Carbon” goals. This study fills the research gap in systematically comparing the synergistic effects of multiple policies by evaluating five key measures (2020–2023) in ultra-low-emission retrofits and clean energy alternatives. Using public macro-data at the national level this study quantified cumulative reductions in air pollutants (SO2 NOx PM VOCs) and CO2. A synergistic control effect coordinate system and a normalized synergistic emission reduction equivalent (APeq) model were employed. The results reveal significant differences: Sintering machine desulfurization and denitrification (SDD) showed the highest APeq but increased CO2 emissions in 2023. Dust removal equipment upgrades (DRE) and unorganized emission control (UEC) demonstrated stable co-reduction effects. While electric furnace short-process steelmaking (ES) and hydrogen metallurgy (HM) showed limited current benefits they represent crucial deep decarbonization pathways. The framework provides multi-dimensional policy insights beyond simple ranking suggesting balancing short-term pollution control with long-term transition by prioritizing clean alternatives.

Hydrogen fuel cell systems are a viable option for electrified aero engines due to their efficiency and environmental benefits. However integrating these systems presents challenges notably in terms of overall system weight and thermal management. Heat exchangers are crucial for the effective thermal management system of electric propulsion systems in commercial electrified aviation. This paper provides a comprehensive review of various heat exchanger types and evaluates their potential applications within these systems. Selection criteria are established based on the specific requirements for air and hydrogen heat exchangers in electrified aircraft. The study highlights the differences in weighting criteria for these two types of heat exchangers and applies a weighted point rating system to assess their performance. Results indicate that extended surface microchannel and printed circuit heat exchangers exhibit significant promise for aviation applications. The paper also identifies key design challenges and research needs particularly in enhancing net heat dissipation increasing compactness improving reliability and ensuring effective integration with aircraft systems.

The passive combination of fuel cells and supercapacitors possesses promising applications in the automotive industry due to its ability to decrease stack size maintain peak power capacity improve system productivity and go away with the need for additional control all without Direct current to Direct Current (DC/DC) converters. This research describes the steps to create and evaluate a fuel cell (FC) and supercapacitor (SC) passive hybrid electrical system for a 60-V lightweight vehicle. Also study offers a thorough design approach and model and experimentally to validate every passive hybrid testing station component. When both concepts are stable the voltage errors are about 2 % and 3 % respectively for fuel cells and supercapacitors. The results of the experiments provide more evidence that the passive design is effective under step loads and driving cycles. The results of the measurements match the models used to simulate the passive hybrid system if a step load voltage is used. A smaller FC stack is possible since the fuel cell controls the steady-state current. Alternatively the supercapacitors provide varying currents because of their reduced resistance. This study use a driving cycle to show that the FC stack can lower its output to 25 % of the peak power required by the load.

The inherent randomness and intermittency of offshore renewable energy sources such as wind and solar power pose significant challenges to the stable and secure operation of the power grid. These fluctuations directly affect the performance of grid-connected systems particularly in terms of harmonic distortion and load response. This paper addresses these challenges by proposing a novel harmonic control strategy and load response optimization approach. An integrated three-winding transformer filter is designed to mitigate high-frequency harmonics and a control strategy based on converter-side current feedback is implemented to enhance system stability. Furthermore a hybrid PI-VPI control scheme combined with feedback filtering is employed to improve the system’s transient recovery capability under fluctuating load and generation conditions. Experimental results demonstrate that the proposed control algorithm based on a transformer-oriented model effectively suppresses low-order harmonic currents. In addition the system exhibits strong anti-interference performance during sudden voltage and power variations providing a reliable foundation for the modulation and optimization of offshore wind–solar coupled hydrogen production power supply systems.

With the increasing maturity of renewable energy technologies and the pressing need to address climate change urban power systems are striving to integrate a higher proportion of low-carbon renewable energy sources. However the inherent variability and intermittency of wind and solar power pose significant challenges to the stability and reliability of urban power grids. Existing research has primarily focused on short-term energy storage solutions or small-scale integrated energy systems which are insufficient to address the long-term large-scale energy storage needs of urban areas with high renewable energy penetration. This paper proposes a mid-to-long-term capacity expansion model for hydrogen energy storage in urban-scale power systems using Shanghai as a case study. The model employs mixed-integer linear programming (MILP) to optimize the generation portfolios from the present to 2060 under two scenarios: with and without hydrogen storage. The results demonstrate that by 2060 the installed capacity of hydrogen electrolyzers could reach 21.5 GW and the installed capacity of hydrogen power generators could reach 27.5 GW accounting for 30% of the total installed capacity excluding their own. Compared to the base scenario the electricity–hydrogen collaborative energy supply system increases renewable penetration by 11.6% and utilization by 12.9% while reducing the levelized cost of urban comprehensive electricity (LCOUCE) by 2.514 cents/kWh. These findings highlight the technical feasibility and economic advantages of deploying long-term hydrogen storage in urban grids providing a scalable solution to enhance the stability and efficiency of high-renewable urban power systems.

Hydrogen (H2) fuel is one of eco-friendly resources for delivering de-carbonized and sustainable electricity supply in line with the UN’s Sustainable Development Goals 7 and 13 for affordable and clean energy and climate change action respectively. This paper presents a state-of-the art review of the H2 energy resource in terms of its history and evolution production techniques global economy market perspective and application to microgrid systems. It also introduces a systematic classification of the fuel. The production techniques examined include: the thermal approach such as the reforming gasification and thermochemical processes; the photocatalytic approach otherwise called artificial photosynthesis; the biological and photonic approach that involves the photolysis photo-fermentation dark fermentation CO gas fermentation and biomass valorization processes to produce H2 while the electrical approach is based on the chemical dissociation of electrolytes into their constituent ions by the passage of electric current. A particular attention is paid to the potential of the H2 resource in running some energy generators in microgrid systems such as the internal combustion engines microturbines and the fuel cells that are useful for combined heat and power application. The paper introduces different technical configurations topologies and processes that involve the use of green H2 fuel in generating systems and the connection of bus bars power converters battery bank and the electrical and thermal loads. The paper also presents hybrid fuel cell (FC) and PV system simulation using System Advisor Model (SAM) to showcase the use of H2 fuel in a micogrid. The paper provides insightful directions into the H2 economy smart electrical grid and the future prospects.

Zero-emission fuels are expected to drive the maritime sector decarbonisation with hydrogen emerging as a long-term solution. This study aims to investigate by using CFD modelling a hydrogen fuelled marine dual-fuel engine to identify operating settings ranges for different hydrogen energy fractions (HEF) as well as parametrically optimise the diesel fuel injection timing and temperature at inlet valve closing (IVC). A large marine four-stroke engine with nominal power of 10.5 MW at 500 rev/m is considered assuming operation at 90 % load and hydrogen injection in the cylinders intake ports. CFD models are developed for several operating scenarios in both diesel and dual-fuel modes. The models are validated against measured data for the engine diesel mode and literature data for a hydrogen-fuelled light-duty engine. A convergence study is conducted to select the grid compromising between computational effort and accuracy. Parametric runs for 20 % 40 % and 60 % HEF with different IVC temperature and diesel start of injection are modelled to quantify the engine performance emissions and combustion characteristics. A single parameter optimisation is conducted to determine the most effective pilot diesel injection timings. The results reveal the IVC temperature range for stable hydrogen combustion to avoid incomplete combustion at low IVC temperature and knocking above 360 K. The proposed settings lead to higher peak heat release rate and in-cylinder pressure compared to the diesel mode without exceeding the permissible in-cylinder pressure rise limits for 60 % HEF. However NOx emissions increase to 12.9 g/kWh in the dual-fuel mode. The optimal start of injection (SOI) for the diesel fuel in the case of 60 % HEF is found 8 ◦CA BTDC resulting in an indicated thermal efficiency of 43.2 % and stable combustion. Advancing SOI beyond the optimal value results in incomplete combustion. This is the first study on hydrogen use in large marine four-stroke engines providing insights for the engine design and operation and as such it contributes to the maritime industry decarbonisation efforts.

Developing new injection systems and combustion chambers for hydrogen is a central topic for the new generation of engines. In this effort simulations take a central role but methods developed for conventional hydrocarbons (methane kerosene) must be revisited for hydrogen. Validation then becomes an essential part and clean well documented experiments are needed to guaranty that computational fluid dynamics solvers are as predictive and accurate as expected. In this framework the HYLON case is a swirled hydrogen/air burner used by multiple groups worldwide to validate simulation methods for hydrogen combustion in configurations close to gas turbine burners with experimental data available through the TNF web site. The present study compares recent Raman spectroscopy and Particle Image Velocimetry measurements and Large Eddy Simulations (LES). The LES results are evaluated against a dataset comprising mean and RMS measurements of H2 N2 O2 H2O molar fractions temperature and velocity fields offering new insights into flame stabilization mechanisms. The simulations incorporate conjugate heat transfer to predict the combustor wall temperatures and are conducted for two atmospheric-pressure operating conditions each representing distinct combustion regimes diffusion and partially premixed. Novelty and significance statement Data on confined hydrogen flames in burner similar as industrial ones are limited. This work aims to fill this gap by performing multiple and simultaneous diagnostics on the swirled hydrogen-air flame called HYLON. For the first time in such a swirled configuration mean and RMS fields of temperature main species and velocities are compared to LES allowing new insight into the potential and limits of the models as well as the physics of these flames. These experimental results will be made available on TNF as over 30 research groups worldwide have expressed interest in using them.

The integration of renewable resources with advanced storage technologies is critical for sustainable energy systems. In this paper a planning framework for an energy hub incorporating hydrogen and renewable energy systems is developed with the objective of minimizing operational costs while participating in flexible ramping product (FRP) markets. The energy hub is designed to utilize a hybrid storage system comprising multi-type battery energy storage (BESS) accounting for diverse chemistries and degradation behaviors and hydrogen storage (HS) to meet concurrent electric and hydrogen demands. To address uncertainties in renewable generation and market prices a stochastic optimization model is developed to determine the optimal investment capacities while optimizing operational decisions under uncertainty using scenario-based stochastic programming. Financial risks associated with price and renewable variability are mitigated through the Conditional Value-at-Risk (CVaR) metric. Case studies demonstrate that hybrid storage systems including both BESS and HS can reduce total costs by 23.62% compared to single-storage configurations that rely solely on BESS. Based on the results BESS participates more in providing flexible ramp-up services while HS plays a major role in providing flexible ramp-down services. The results emphasize the critical role of co-optimized hydrogen and multi-type BESS in enhancing grid flexibility and economic viability.

Reducing CO2 emissions in general aviation is a critical challenge where battery electric and fuel cell technologies face limitations in energy density cost and robustness. As a result hydrogen (H2) dual-fuel combustion is a promising alternative but its practical implementation is constrained by abnormal combustion phenomena such as knocking and pre-ignition which limit the achievable H2 energy share. In response to these challenges this paper focuses on strategies to mitigate these irregular combustion phenomena while effectively increasing the H2 energy share. Experimental evaluations were conducted on an engine test bench using a one-cylinder dual-fuel H2 kerosene (Jet A-1) engine utilizing two strategies including water injection (WI) and rising the air–fuel ratio (AFR) by increasing the boost pressure. Additionally crucial combustion characteristics and emissions are examined and discussed in detail contributing to a comprehensive understanding of the outcomes. The results indicate that these strategies notably increase the maximal possible hydrogen energy share with potential benefits for emissions reduction and efficiency improvement. Finally through the use of 0D/1D simulations this paper offers critical thermodynamic and efficiency loss analyses of the strategies enhancing the understanding of their overall impact.

Introduction: With the increasing demand for energy utilization efficiency and minimization of environmental carbon emissions in industrial parks optimizing the configuration and scheduling of integrated energy systems has become crucial. This study focuses on integrated energy systems with massive flexible load resources aiming to maximize energy utilization efficiency while reducing environmental impact. Methods: To model the uncertainties in wind and solar power outputs we employed three-parameter Weibull distribution models and Beta distribution models. Flexible loads were categorized into three types to match different electricity consumption patterns. Additionally an enhanced Kepler Optimization Algorithm (EKOA) was proposed incorporating chaos mapping and adaptive learning rate strategies to improve search scope convergence speed and solution efficiency. The effectiveness of the proposed optimization scheduling and configuration methods was validated through a case study of an industrial park located in a coastal area of southeastern China. Results: The results show that using three-parameter Weibull distribution models and Beta distribution models more accurately reflects the variations in actual wind speeds and solar irradiance levels achieving peak shaving and valley filling effects and enhancing renewable energy utilization. The EKOA algorithm significantly reduced curtailment rates of wind and solar power generation while achieving substantial economic benefits. Compared with other operation modes of hydrogen the daily average cost is reduced by 12.92% and external electricity purchases are reduced by an average of 20.2 MW h/day. Discussion: Although our approach shows potential in improving energy utilization efficiency and economic gains this paper only considered hydrogen energy for single-use pathways and did not account for the economic benefits from selling hydrogen in the market. Future research will further incorporate hydrogen demand response mechanisms and optimize the output of integrated energy systems from the perspective of spot markets. These findings provide valuable references for relevant engineering applications.

This study focuses on the power systems of inland waterway vessels in Chinese Yangtze River systematically outlining the low-carbon technology pathways for different power system types. A comparative analysis is conducted on the technical feasibility emission reduction potential and economic viability of LNG methanol ammonia pure electric and hybrid power systems revealing the bottlenecks hindering the large-scale application of each system. Key findings indicate that: (1) LNG and methanol fuels offer significant short-term emission reductions in internal combustion engine power systems yet face constraints from methane slip and insufficient green methanol production capacity respectively; (2) ammonia enables zero-carbon operations but requires breakthroughs in combustion stability and synergistic control of NOX; (3) electric vessels show high decarbonization potential but battery energy density limits their range while PEMFC lifespan constraints and SOFC thermal management deficiencies impede commercialization; (4) hybrid/range-extended power systems with superior energy efficiency and lower retrofitting costs serve as transitional solutions for existing vessels though challenged by inadequate energy management strategies and multi-equipment communication protocol interoperability. A phased transition pathway is proposed: LNG/methanol engines and hybrid systems dominate during 2025–2030; ammonia-powered systems and solid-state batteries scale during 2030–2035; post-2035 operations achieve zero-carbon shipping via green hydrogen/ammonia.

To reduce fossil fuel dependency in shipping adopting alternative fuels and innovative propulsion systems is essential. Solid Oxide Fuel Cells (SOFC) powered by hydrogen carriers represent a promising solution. This study investigates a multi-fuel SOFC system for ocean-going vessels capable of operating with ammonia methanol or hydrogen thus enhancing bunkering flexibility. A thermodynamic model is developed to simulate the performance of a 3 kW small-scale system subsequently scaling up to a 10 MW configuration to meet the power demand of a container ship used as the case study. Results show that methanol is the most efficient fueling option reaching a system efficiency of 58% while ammonia and hydrogen reach slightly lower values of about 55% and 51% respectively due to higher auxiliary power consumption. To assess technical feasibility two installation scenarios are considered for accommodating multiple fuel tanks. The first scenario seeks the optimal fuel share equivalent to the diesel tank’s chemical energy (17.6 GWh) minimizing mass increase. The second scenario optimizes the fuel share within the available tank volume (1646 m3 ) again minimizing mass penalties. In both cases feasibility results have highlighted that changes are needed in terms of cargo reduction equal to 20.3% or alternatively in terms of lower autonomy with an increase in refueling stops. These issues can be mitigated by the benefits of increased bunkering flexibility

This report assesses the market readiness of zero-emission heavy-duty vehicles and the required infrastructure to meet the 45% emission reduction targets set by the revised CO2 standards by 2030. Achieving these goals requires the widespread adoption of zero-emission vehicles and a robust recharging and hydrogen refuelling infrastructure Three main aspects are investigated: the market readiness of the vehicles considering both the demand and supply side the corresponding infrastructure requirements and the barriers. Building on the inputs of the stakeholders a ‘study scenario’ is developed. This scenario shows a concrete picture of what the zero-emission heavy-duty vehicle fleet and its infrastructure requirement could look like by 2030. There are however key barriers that need to be overcome such as high total cost of ownership limited electricity grid capacity lengthy permitting processes and uncertainty in hydrogen availability and pricing. Stakeholders also emphasize the importance of policy drivers such as emissions trading systems and tolling and tax reforms to stimulate demand. In conclusion achieving the 2030 targets demands a coordinated approach involving manufacturers operators and policymakers to address infrastructure gaps market barriers and policy incentives ensuring the transition to a zero-emission HDV fleet.

The use of hydrogen as a fuel for piston engines enables environmentally friendly and efficient operation. However several challenges arise in the combustion process limiting the development of hydrogen engines. These challenges include abnormal combustion the high burning velocity of hydrogen-enriched mixtures increased nitrogen oxide emissions and others. A rational organization of hydrogen combustion can partially or fully mitigate these issues through the use of advanced methods such as late direct injection charge stratification dual injection jet-guided operation and others. However mathematical models describing hydrogen combustion for these methods are still under development complicating the optimization and refinement of hydrogen engines. Previously we proposed a mathematical model based on Wiebe functions to describe premixed and diffusion combustion as well as relatively slow combustion in lean-mixture zones behind the flame front and near-wall regions. This study further develops the model by accounting for the combined influence of the mixture composition and engine speed mixture stratification and the effects of injection and ignition parameters on premixed and diffusion combustion. Special attention is given to combustion modeling in an engine with single injection and jet-guided operation.

With the global commercialization of hydrogen fuel cell vehicles the number of hydrogen refueling stations is steadily increasing. On-site hydrogen production stations are expected to play a key role in future power systems by absorbing renewable energy and supplying electricity during peak grid loads aiding in peak shaving and load leveling. However renewable energy sources like photovoltaic (PV) systems have highly fluctuating power generation curves making it difficult to provide stable energy for hydrogen production. Traditional stations mainly use alkaline electrolyzers (AE) which are sensitive to power fluctuations leading to operational instability. To address this this paper proposes using capacitors and energy storage batteries to mitigate PV fluctuations and introduces a combined AE and Proton Exchange Membrane (PEM) electrolyzer hydrogen production method. Study cases demonstrate that capacitors and energy storage batteries reduce the variance of PV power output by approximately 0.02. Building on this the hybrid approach leverages the low cost of AE and the rapid response of PEM electrolyzers to better adapt to PV fluctuations and maximize PV absorption. The model is mathematically formulated and the station’s equipment planning and operational strategy are optimized using CPLEX. The results show that compared to pure AE and PEM hydrogen production the combined AE and PEM hydrogen production method reduces the total annual cost of the hydrogen refueling station by 4.3% and 5.9% respectively.

Decarbonizing the steel industry will require a shift towards renewable energy. However costs and emissions associated with the long-distance transport of renewable energy carriers may incentivize the relocation of steel production closer to renewable energy sources. This “green relocation” would affect regional economic structures and global trade patterns. Nevertheless the macroeconomic and environmental impacts of alternative industry location options remain underexplored. This study compares the impacts on value-added prices and emissions under two options for decarbonizing the Dutch steel industry: importing green hydrogen from Brazil to produce green steel in the Netherlands versus relocating production to Brazil and transporting green steel to the Netherlands. Impacts are analyzed by combining a price and a quantity model within an environmentally extended multiregional input-output (EE-MRIO) framework. Results suggest that the relocation option brings the greatest synergies between climate and economic goals at the global level as it leads to lower production costs smaller price effects and greater emissions reductions. However relocation also results in stronger distributive impacts across global regions. Higher carbon prices would be insufficient to counteract relocation incentives. This calls for policymakers in industrialized countries to systematically consider the possibility of green relocation when designing decarbonization and industrial competitiveness strategies.

Model predictive control (MPC) requires high accuracy of the model. However the actual power system has complex dynamic characteristics. There must be unmodeled dynamics in the system modeling process which makes it difficult for MPC to perform the function of optimal control. ESO has the ability to observe and suppress errors combining the both can solve this problem. Thus this paper proposes a coordinated control strategy of hydrogen-energy storage system based on disturbance-rejection model predictive controller. Firstly this paper constructs the state-space model of the system and improves MPC. By connecting ESO and MPC in series this paper designs a matched disturbance-rejection model predictive controller and analyzes the robustness of the research system. Finally this paper verifies the effectiveness and feasibility of the disturbance-rejection model predictive controller under various working conditions. Compared with the method using only MPC the dynamic response time of the system frequency regulation under the proposed strategy in this paper is increased by about 29.9 % and the frequency drop rate is slowed down by 13.5 %. In addition under the AGC command and continuous load disturbance working conditions the maximum frequency deviation of the system under the proposed strategy is reduced by about 54.01 % and 48.96 %. The results clearly show that the proposed strategy in this paper significantly improves the dynamic response ability of the system and reduces the frequency fluctuation of the system after disturbance.

The spark-ignited (SI) hydrogen combustion engine has the potential to noticeably reduce greenhouse gas emissions from passenger cars. To prevent nitrogen oxide emissions and to increase fuel efficiency and power output complex air paths and operating strategies are utilized. This makes the engine control problem more complex challenging the conventional engine calibration process. This work combines and extends the state-of-the-art in real-time combustion engine modeling and optimal control presenting a novel control concept for the efficient operation of a hydrogen combustion engine. The extensive experimental validation with a 1.5 l three-cylinder hydrogen SI engine and a dynamically operated engine test bench with emission and in-cylinder pressure measurements provides a comprehensible comparison to conventional engine control. The results demonstrate that the proposed optimal control decreased the load tracking errors by a factor of up to 2.8 and increased the engine efficiency during lean operation by up to 10 percent while decreasing the calibration effort compared to conventional engine control.