Applications & Pathways

The analysis aims to determine the most efficient and cost-effective way of providing power to a remote site. The two primary sources of power being considered are photovoltaics and small wind turbines while the two potential storage media are a battery bank and a hydrogen storage fuel cell system. Subsequently the hydrogen is stored within a reservoir and employed as required by the fuel cell. This strategy offers a solution for retaining surplus power generated during peak production phases subsequently utilizing it during periods when the renewable power sources are generating less power. To evaluate the performance of the hydrogen storage system the analysis included a sensitivity analysis of the wind speed and the cost of the hydrogen subsystem. In this analysis the capital and replacement costs of the electrolyzer and hydrogen storage tank were linked to the fuel cell capital cost. As the fuel cell cost decreases the cost of the electrolyzer and hydrogen tank also decreases. The optimal system type graph showed that the hydrogen subsystem must significantly decrease in price to become competitive with the battery bank.

In the quest to achieve “double carbon” goals the urgency to develop an efficient Integrated Energy System (IES) is paramount. This study introduces a novel approach to IES by refining the conventional Power-to-Gas (P2G) system. The inability of current P2G systems to operate independently has led to the incorporation of hydrogen fuel cells and the detailed investigation of P2G’s dual-phase operation enhancing the integration of renewable energy sources. Additionally this paper introduces a carbon trading mechanism with a refined penalty–reward scale and a detailed pricing tier for carbon emissions compelling energy suppliers to reduce their carbon footprint thereby accelerating the reduction in system-wide emissions. Furthermore this research proposes a flexible adjustment mechanism for the heat-to-power ratio in cogeneration significantly enhancing energy utilization efficiency and further promoting conservation and emission reductions. The proposed optimization model in this study focuses on minimizing the total costs including those associated with carbon trading and renewable energy integration within the combined P2G-Hydrogen Fuel Cell (HFC) cogeneration system. Employing a bacterial foraging optimization algorithm tailored to this model’s characteristics the study establishes six operational modes for comparative analysis and validation. The results demonstrate a 19.1% reduction in total operating costs and a 22.2% decrease in carbon emissions confirming the system’s efficacy low carbon footprint and economic viability.

Multi-energy microgrids (MEMGs) with green hydrogen have attracted significant research attention for their benefits such as energy efficiency improvement carbon emission reduction as well as line congestion alleviation. However the complexities of multi-energy networks coupled with diverse uncertainties may threaten MEMG’s operation. In this paper a data-driven methodology is proposed to achieve effective MEMG operation considering the green hydrogen technique and congestion management. First a detailed MEMG modelling approach is developed coupling with electricity green hydrogen natural gas and thermal flows. Different from conventional MEMG models hydrogen-enriched compressed natural gas (HCNG) models and weatherdependent power flow are thoroughly considered in the modelling. Meanwhile the power flow congestion problem is also formulated in the MEMG operation which could be mitigated through HCNG integration. Based on the proposed MEMG model a reinforcement learning-based method is designed to obtain the optimal solution of MEMG operation. To ensure the solution’s safety a soft actor-critic (SAC) algorithm is applied and modified by leveraging the Lagrangian relaxation and safety layer scheme. In the end case studies are conducted and presented to validate the effectiveness of the proposed method.

This paper proposes a numerical setup for 3D-CFD in-cylinder simulations of H2-fuelled internal combustion engines. The flamelet G-equation model based on Verhelst and Damkohler-like ¨ correlations for laminar and turbulent flame speeds respectively is used to reproduce the flame propagation. The validation against experimental data from a homogeneous-mixture port-injection engine enables a focus on combustion simulation by minimising stratification uncertainties. Accurate flame propagation modelling is identified as the main challenge. The results on different operating conditions confirm the predictive capabilities of the framework thanks to the agreement with the experimental pressure traces combustion indicators and flame imaging. Notably combustion rate predictions remain accurate even without considering the flame thermo-diffusive instability as the turbulence effect dominates at the investigated conditions. The combustion regime is analysed by a modified Borghi-Peters diagram and it ranges from flamelet to thin reaction zones. This highlights the numerical setup flexibility which accurately simulates combustion across different regimes.

Many off-grid communities in Canada are dependent on diesel generators to fulfill their utility and transportation needs causing destructive environmental impact. This study aims to optimize and investigate the technoeconomic feasibility of a hybrid renewable energy system to satisfy the 1.6 MWh/day electricity 184.2 kWh/day thermal and 428.38 kg/year hydrogen demand simultaneously Trout Lake a remote community of Northern Alberta. A novel hybrid energy system consisting of solar PV wind turbine electrolyzer hydrogen tank battery fuel cell hydrogen boiler and thermal load controller has been proposed to generate electricity heat and hydrogen by renewables which reduce carbon emission utilizing the excess energy (EE). Five different scenarios were developed in HOMER Pro software and the results were compared to identify the best combination of hybrid renewable energy systems. The results indicate that the fifth scenario is the optimal renewable energy system that provides a lower cost of energy (COE) at $0.675/kWh and can reduce 99.99% carbon emission compared to the diesel-based system. Additionally the utilization of thermal load controller battery and fuel cell improved the system’s reliability increasing renewable fraction (RF) (93.5%) and reducing EE (58.3%) significantly. In comparison to the diesel-based systems it is also discovered that battery energy storage is the most affordable option while fuel cells are the more expensive choice for remote community. Sensitivity analyses are performed to measure the impact of different dominating factors on COE EE and RF.

This review synthesizes recent research on alternative fuels for piston-engine aircraft and related propulsion technologies. Biofuels show substantial promise but face technological economic and regulatory barriers to widespread adoption. Among liquid options biodiesel offers a high cetane number and strong lubricity yet suffers from poor low-temperature flow and reduced combustion efficiency. Alcohol fuels (bioethanol biomethanol) provide high octane numbers suited to high-compression engines but are limited by hygroscopicity and phase-separation risks. Higher-alcohols (biobutanol biopropanol) combine favorable heating values with stable combustion and emerge as particularly promising candidates. Biokerosene closely matches conventional aviation kerosene and can function as a drop-in fuel with minimal engine modifications. Emissions outcomes are mixed across studies: certain biofuels reduce NOx or CO while others elevate CO2 and HC underscoring the need to optimize combustion and advance second- to fourth-generation biofuel production pathways. Beyond biofuels hydrogen engines and hybrid-electric systems offer compelling routes to lower emissions and improved efficiency though they require new infrastructure certification frameworks and cost reductions. Demonstrated test flights with biofuels synthetic fuels and hydrogen confirm technical feasibility. Overall no single option fully replaces aviation gasoline today; instead a combined trajectory—biofuels alongside hydrogen and hybrid-electric propulsion—defines a pragmatic medium- to long-term pathway for decarbonizing general aviation.

The growing share of renewables in power grids increases the need for backup generators able to compensate production profiles whenever needed. Hydrogen internal combustion engines (H2 ICEs) offer a promising solution in terms of flexibility reduced capital cost and looser requirements on hydrogen purity. These systems are however still not well characterized. This study introduces a zero-dimensional (0D) model for a 100 % hydrogen engine calibrated using experimental data under varying loads and air-fuel ratios. Unlike existing models it proposes validated electrical efficiency data across multiple operating points. Efficiency curves are provided in quadratic and linear forms allowing integration into diverse energy system simulations including linear programming. The model performance is evaluated in a peak-shaving case study using real data from a remote site with limited grid supply. Three engine-generators are used to match single-minute resolution load demand. Compared to typical models that lack validation and ignore part-load efficiency losses the proposed model highlights differences in hydrogen consumption estimation up to 13.4 % thus offering improved accuracy for techno-economic analyses of hydrogen-based systems.

In the context of energy interconnection and low-carbon power the power-to-gas (P2G) carbon trading mechanism is integrated into the integrated energy system (IES) model of multi-energy coupling units to achieve lowcarbon economic dispatch considering both the economic and environmental benefits of system operation. First the characteristics of each unit in the system are comprehensively considered and a joint dispatch structure for a regionally integrated energy system is developed including P2G equipment energy source equipment storage equipment and conversion equipment. The working mechanism of P2G is analyzed and its carbon trading model is established. Next a comprehensive energy system optimization model is formulated with the goal of maximizing system operating profit while accounting for carbon transaction costs. Finally Cplex and Yalmip software are used to perform simulation analysis in MATLAB to verify the effectiveness of the proposed model in reducing system carbon emissions through participation in the carbon trading market ensuring system economy and reducing the dependence of the integrated energy system on the external market.

Driven by carbon neutrality and peak carbon policies hydrogen energy due to its zeroemission and renewable properties is increasingly being used in hydrogen fuel cell vehicles (H-FCVs). However the high cost and limited durability of H-FCVs hinder large-scale deployment. Hydrogen internal combustion engine hybrid electric vehicles (H-HEVs) are emerging as a viable alternative. Research on the techno-economics of H-HEVs remains limited particularly in systematic comparisons with H-FCVs. This paper provides a comprehensive comparison of H-FCVs and H-HEVs in terms of total cost of ownership (TCO) and hydrogen consumption while proposing a multi-objective powertrain parameter optimization model. First a quantitative model evaluates TCO from vehicle purchase to disposal. Second a global dynamic programming method optimizes hydrogen consumption by incorporating cumulative energy costs into the TCO model. Finally a genetic algorithm co-optimizes key design parameters to minimize TCO. Results show that with a battery capacity of 20.5 Ah and an H-FC peak power of 55 kW H-FCV can achieve optimal fuel economy and hydrogen consumption. However even with advanced technology their TCO remains higher than that of H-HEVs. H-FCVs can only become cost-competitive if the unit power price of the fuel cell system is less than 4.6 times that of the hydrogen engine system assuming negligible fuel cell degradation. In the short term H-HEVs should be prioritized. Their adoption can also support the long-term development of H-FCVs through a complementary relationship.

One of the primary contributors to automobile exhaust pollution is the significant deviation be tween the actual and theoretical air-fuel ratios during transient conditions leading to a decrease in the conversion efficiency of three-way catalytic converters. Therefore it becomes imperative to enhance fuel economy reduce pollutant emissions and improve the accuracy of transient control over air-fuel ratio (AFR) in order to mitigate automobile exhaust pollution. In this study we propose a Linear Active Disturbance Rejection Control (LADRC) Hydrogen Doping Compensation Controller (HDC) to achieve precise control over the acceleration transient AFR of gasoline en gines. By analyzing the dynamic effects of oil film and its impact on AFR we establish a dynamic effect model for oil film and utilize hydrogen’s exceptional auxiliary combustion characteristics as compensation for fuel loss. Comparative experimental results demonstrate that our proposed algorithm can rapidly regulate the AFR close to its ideal value under three different transient conditions while exhibiting superior anti-interference capability and effectively enhancing fuel economy.

Recent advances in hydrogen internal combustion technologies highlight its potential for high efficiency and zero carbon emissions offering a promising alternative to fossil fuels. This paper investigates the effects of valve timings and overlaps on engine performance combustion characteristics and emissions in a boosted directinjection single-cylinder spark ignition engine using both gasoline and hydrogen. Optimized direct hydrogen injection effectively eliminates backfires and hydrogen slip during positive cam overlaps significantly reducing the pumping mean effective pressure. The study’s primary finding demonstrates the potential of hydrogen to operate as a direct substitute for a gasoline engine without necessitating changes to the cam profiles at the high load operation. Furthermore the study demonstrates that hydrogen leads to much higher thermal efficiencies across a wider range of engine loads when operated at a lean air-to-fuel ratio of 2.75. The engine operating with such a lean-burn hydrogen mixture keeps the engine-out NOx emission at ultra-low levels. Compared to gasoline hydrogen exhibits greater stability and a reduced reliance on camshaft timing during engine operation.

The EU Horizon2020 RISE project 778307 “Hydrogen fuelled utility and their support systems utilising metal hydrides” (HYDRIDE4MOBILITY) worked on the commercialization of hydrogen powered forklifts using metal hydride (MH) based hydrogen stores. The project consortium joined forces of 9 academic and industrial partners from 4 countries. The work program included a) Development of the materials for hydrogen storage and compression; b) Theoretical modelling and optimisation of the materials performance and system integration; c) Advanced fibre reinforced composite cylinder systems for H2 storage and compression; d) System validation. Materials development was focused on i) Zr/Ti-based Laves type high entropy alloys; ii) Mg-rich composite materials; iii) REMNiSn intermetallics; iv) Mg based materials for the hydrolysis process; v) Cost-efficient alloys. For the optimized AB2±x alloys the Zr/Ti content was optimized at A = Zr78-88Ti12–22 while B=Ni10Mn5.83VFe. These alloys provided a) Low hysteresis of hydrogen absorption-desorption; b) Excellent kinetics of charge and discharge; c) Tailored thermodynamics; d) Long cycle life. Zr0.85Ti0.15TM2 alloy provided a reversible H storage and electrochemical capacity of 1.6 wt% H and 450 mAh/g. The tanks development targeted: i) High efficiency of heat and hydrogen exchange; ii) Reduction of the weight and increasing the working H2 pressure; iii) Modelling testing and optimizing the H2 stores with fast performance. The system for power generation was validated at the Implats plant in a fuel cell powered forklift with on-board MH hydrogen storage and on-site H2 refuelling. The outcome on the HYDRIDE4MOBILITY project (2017–2024) (http://hydride4mobility.fesb.unist. hr) was presented in 58 publications.

The polymer electrolyte membrane (PEM) fuel cell system is considered to be an ideal alternative for the internal combustion engine especially when used on a city bus. Hybrid buses with fuel cell systems and energy storage systems are now undergoing transit service demonstrations worldwide. A hybrid PEM fuel cell city bus with a hierarchical control system is studied in this paper. Firstly the powertrain and hierarchical control structure is introduced. Secondly the vehicle control strategy including start-stop strategy energy management strategy and fuel cell control strategy including the hydrogen system and air system control strategies are described in detail. Finally the performance of the fuel cell was analyzed based on road test data. Results showed that the different subsystems were well-coordinated. Each component functioned in concert in order to ensure that both safety and speed requirements were satisfied. The output current of the fuel cell system changed slowly and the output voltage was limited to a certain range thereby enhancing durability of the fuel cell. Furthermore the economic performance was optimized by avoiding low load conditions.

This manuscript presents a comprehensive technical review of low-temperature proton exchange membrane fuel cells (LT-PEMFCs) focusing on their performance applications and current challenges within commercial contexts. LT-PEMFCs have reached commercial deployment in light-duty vehicles buses trains heavy-duty trucks stationary combined heat and power units and early maritime platforms. This review consolidates datasheetbased specifications and reconstructed performance parameters from leading manufacturers complemented by qualitative evidence from large-scale deployments in Japan and China to provide the first cross-sectoral benchmarking of LT-PEMFC systems. The analysis is structured around the key performance indicators (KPIs) of the Clean Hydrogen Joint Undertaking and the U.S. Department of Energy which define quantitative targets for 2024 and 2030. Results show that while several light-duty and bus platforms already meet or approach KPI compliance for hydrogen consumption and efficiency other sectors such as heavy-duty stationary and maritime remain below target ranges due to integration constraints and limited transparency in datasheet reporting. The study further highlights divergences between laboratory-reported stack metrics and commercial module specifications demonstrating the need for harmonized definitions of volumetric power density efficiency at rated power and durability. By situating catalogue-only and prototype systems within the technological pipeline the review clarifies how near-term developments may close performance gaps and reduce platinum dependency while also acknowledging the economic and infrastructural dimensions that condition future adoption. This includes recent advances in PGM-free catalysts alloyed and core–shell architectures and ionomer-free electrodes which complement low-PGM approaches in reducing material cost and supply risk. The contribution lies in delivering a transparent and replicable framework that not only maps the current state of LT-PEMFC commercialization but also provides directionality for research policy and industrial innovation on the pathway to 2030 deployment objectives. This represents the first systematic cross-sectoral benchmarking of LTPEMFCs that integrates datasheet-derived and reconstructed specifications with DOE and CHJU KPI frameworks providing both quantitative visualizations and a replicable methodology that clarifies current achievements while indicating where targeted innovation is needed to reach 2030 objectives.

Due to the high cost of hydrogen utilization and the uncertainties in renewable energy generation and load demand significant challenges are posed for the operation optimization of hydrogen-containing integrated energy systems (IESs). In this study a robust operational model for an electric–heat–gas IES (EHG-IES) is proposed considering the hydrogen energy system heat recovery (HESHR) and multiple uncertainties. Firstly a heat recovery model for the hydrogen system is established based on thermodynamic equations and reaction principles; secondly through the constructed adjustable robust optimization (ARO) model the optimal solution of the system under the worst-case scenario is obtained; lastly the original problem is decomposed based on the column and constraint generation method and strong duality theory resulting in the formulation of a master problem and subproblem with mixed-integer linear characteristics. These problems are solved through alternating iterations ultimately obtaining the corresponding optimal scheduling scheme. The simulation results demonstrate that our model and method can effectively reduce the operation and maintenance costs of HESHR-EHG-IES while being resilient to uncertainties on both the supply and demand sides. In summary this study provides a novel approach for the diversified utilization and flexible operation of energy in HESHR-EHG-IES contributing to the safe controllable and economically efficient development of the energy market. It holds significant value for engineering practice.

Renewable Energy Sources (RESs) are characterized by high unevenness cyclicality and seasonality of energy production. Due to the trends in the production of electricity itself and the utilization of hydrogen distributed generation systems are preferred. They can be connected to the energy distribution network or operate without its participation (off-grid). However in both cases such distributed energy sources should be balanced in terms of power generation. According to the authors it is worth combining different RESs to ensure the stability of energy production from such a mix. Within the mix the sources can complement and replace each other. According to the authors an effective system for generating energy from RESs should contain at least two different sources and energy storage. The purpose of the analyses and calculations performed is to determine the characteristics of energy generation from a photovoltaic system and a wind turbine with a specific power and geographical location in the Lublin region in Poland. Another important goal is to determine the substitutability of the sources studied. Probabilistic analysis will be used to determine the share of given energy sources in the energy mix and will allow us to estimate the size of the stationary energy storage. The objective of these procedures is to strive for the highest possible share of renewable energy in the total energy required to charge electric vehicle fleets and to produce low-emission hydrogen for transportation. The article proves that the appropriately selected components of the photovoltaic and wind energy mix located in the right place lead to the self-balancing of the local energy network using a small energy storage. The conclusions drawn from the conducted research can be used by RES developers who intend to invest in new sources of power generation to produce low-emission hydrogen. This is in line with the current policy of the European Union aimed at climate and energy transformation of many companies using green hydrogen.

The marine industry must reduce emissions to comply with recent and future regulations. Solid oxide fuel cells (SOFCs) are seenas a promising option for efficient power generation on ships with reduced emissions. However it is unclear how the devices canbe integrated and how this affects the operation of the ship economically and environmentally. This paper reviews studies thatconsider SOFC for marine applications. First this article discusses noteworthy developments in SOFC systems includingpower plant options and fuel possibilities. Next it presents the design drivers for a marine power plant and explores how anSOFC system performs. Hereafter the possibilities for integrating the SOFC system with the ship are examined alsoconsidering economic and environmental impact. The review shows unexplored potential to successfully integrate SOFC withthermal and electrical systems in marine vessels. Additionally it is identified that there are still possibilities to improve marineSOFC systems for which a holistic approach is needed for design at cell stack module and system level. Nevertheless it isexpected that hybridisation is needed for a technically and economically feasible ship. Despite its high cost SOFC systemscould significantly reduce GHG NO X SO X PM and noise emissions in shipping

In the coming years as a result of changing climate policies and finite fossil fuel resources energy producers will be compelled to introduce new fuels with lower carbon footprints. One of the solutions is hydrogen which can be burned or co-fired with methane in energy generation systems. Therefore this study presents a thermodynamic and emission analysis of a gas turbine fueled by a mixture of CH4 and H2 as well as pure hydrogen. Numerical studies were conducted for the actual operating parameters of the LM6000 gas turbine in both simple and combined cycles. Aspen Hysys and Chemkin-Pro 2023R1 commercial software were used for the calculations. It was demonstrated that with a constant turbine inlet temperature set at 1723 K the thermal efficiency increased from 39.4% to 40.2% for the gas turbine cycle and from 49% to 49.4% for the combined cycle gas turbine. Nitrogen oxides emissions were calculated using the reactor network revealing that an increase in H2 content above 20%vol. in the fuel leads to a significant rise in nitric oxides emissions. In the case of pure H2 emissions are more than three times higher than for CH4 . The main reason for this increase in emissions was identified as the greater presence of H O and OH radicals in the reaction zone causing an acceleration in the formation of nitric oxides.

Enhancing system durability and fuel economy stands as a crucial factor in the energy management of fuel cell hybrid vehicles. This paper proposes an Equivalent Consumption Minimization Strategy (ECMS) based on the Genetic Algorithm (GA) aiming to minimize the overall operating cost of the system. First this study establishes a dynamic model of the hydrogen–electric hybrid vehicle a static input–output model of the hybrid power system and an aging model. Next a speed prediction method based on an Autoregressive Integrated Moving Average (ARIMA) model is designed. This method fits a predictive model by collecting historical speed data in real time ensuring the robustness of speed prediction. Finally based on the speed prediction results an adaptive Equivalence Factor (EF) method using a GA is proposed. This method comprehensively considers fuel consumption and the economic costs associated with the aging of the hydrogen–electric hybrid system forming a total operating cost function. The GA is then employed to dynamically search for the optimal EF within the cost function optimizing the system’s economic performance while ensuring real-time feasibility. Simulation outcomes demonstrate that the proposed energy management strategy significantly enhances both the durability and fuel economy of the fuel cell hybrid vehicle.

During the development of hydrogen fuel cell systems with the augmentation of power conventional air-cooling systems which are frequently employed in portable scenarios encounter difficulties in maintaining the balance between radiator heat dissipation and power consumption. In contrast liquid-cooling systems are widely adopted in high-power applications. In this regard aiming to address the heat dissipation problem and make use of the wastewater from the stack tailpipe a novel spray cooling system integrated with the traditional air-cooling for the radiator of hydrogen fuel cell systems is put forward. Through experimental investigations based on heat transfer theory and the design principles of fuel cell systems it is discovered that under specific nozzle apertures and spray water pressures the heat dissipation rate can be enhanced by 40 % and 30 % respectively. With particular radiator internal water flow rates and fan speeds the heat dissipation rate can be increased by 30 % and 108 % respectively. And the spray angle of 60 ◦ is the best angle. In contrast to the conventional air-cooling system the spray-air cooling system exhibits a heat dissipation rate that is approximately 50 % higher. Exper imental analyses demonstrate that the new system effectively harnesses water resources and enhances the heat dissipation performance of the radiator thereby providing a technical reference for the application of spray cooling in the radiators of hydrogen fuel cell systems.

This study introduces an innovative nuclear-biomass integrated energy and cleaner production multigeneration system incorporating sonohydrogen technology and a desalination unit for the sustainable and efficient production of hydrogen electricity hot water and heat. A small modular nuclear reactor acts as the primary energy source ensuring stable and low-carbon power generation while enhancing hydrogen yield through sonochemical processes. Biomass-derived biogas is strategically utilized for both electricity generation and hydrogen production via steam methane reforming. The heat wasted in the system is efficiently utilized. A high-performance multistage flash desalination unit converts some of the waste heat into desalinated seawater. In addition a portion of the waste heat is utilized for heat production. The results of this study show that the overall energy and exergy efficiencies of the integrated system are 82.7 % and 68.3 % respectively. Through detailed energy and exergy assessments the study demonstrates the feasibility of the proposed system in enhancing energy conversion efficiency improving waste heat utilization and increasing sustainability. In addition the results of the cost assessment show that the integrated energy system is economically viable in the long term with hydrogen production driving substantial annual revenue and profitability projected within the first decade of operation. The findings highlight the system’s potential to contribute to cleaner energy production by reducing greenhouse gas emissions maximizing resource efficiency and advancing hydrogen and freshwater production technologies.

This article presents a study on the distributed optimization operation method for micro-energy grid clusters within an electric thermal and hydrogen integrated energy system. The research focuses on precisely modeling the Power-toHydrogen (P2H) conversion process in electrolytic cells by considering their startup characteristics. An optimization operation model is established with each micro-energy grid as the principal entity to cater to their individual interests and demands. The Alternating Direction Method of Multipliers (ADMM) algorithm is adopted for distributed solution. Case studies demonstrate that the connection topology between micro-energy grids significantly impacts the total operating cost and the effectiveness of the ADMM algorithm is validated through a comparison with centralized optimization approaches.

The transport sector is considered to be a significant contributor to greenhouse gas emissions as this sector emits about one-fourth of global CO2 emissions. Transport emissions contribute toward climate change and have been linked to adverse health impacts. Therefore alternative and sustainable transport options are urgent for decarbonising the transport sector and mitigating those issues. Hydrogen fuel cell vehicles are a potential alternative to conventional vehicles which can play a significant role in decarbonising the future transport sector. This study critically analyses the recent works related to hydrogen fuel cell integration into vehicles modelling and experimental investigations of hydrogen fuel cell vehicles with various powertrains. This study also reviews and analyses the performance energy management strategies lifecycle cost and emissions of fuel cell vehicles. Previous literature suggested that the fuel consumption and well-to-wheel greenhouse gas emissions of hydrogen fuel cell-powered vehicles are significantly lower than that of conventional internal combustion vehicles. Hydrogen fuel cell vehicles consume about 29–66 % less energy and cause approximately 31–80 % less greenhouse gas emissions than conventional vehicles. Despite this the lifecycle cost of hydrogen fuel cell vehicles has been estimated to be 1.2–12.1 times higher than conventional vehicles. Even though there has been recent progress in energy management in hydrogen fuel cell electric vehicles there are a number of technical and economic challenges to the commercialisation of hydrogen fuel cell vehicles. This study presents current knowledge gaps and details future research directions in relation to the research advancement of hydrogen fuel cell vehicles.

Ammonia a molecule that is gaining more interest as a fueling vector has been considered as a candidate to power transport produce energy and support heating applications for decades. However the particular characteristics of the molecule always made it a chemical with low if any benefit once compared to conventional fossil fuels. Still the current need to decarbonize our economy makes the search of new methods crucial to use chemicals such as ammonia that can be produced and employed without incurring in the emission of carbon oxides. Therefore current efforts in this field are leading scientists industries and governments to seriously invest efforts in the development of holistic solutions capable of making ammonia a viable fuel for the transition toward a clean future. On that basis this review has approached the subject gathering inputs from scientists actively working on the topic. The review starts from the importance of ammonia as an energy vector moving through all of the steps in the production distribution utilization safety legal considerations and economic aspects of the use of such a molecule to support the future energy mix. Fundamentals of combustion and practical cases for the recovery of energy of ammonia are also addressed thus providing a complete view of what potentially could become a vector of crucial importance to the mitigation of carbon emissions. Different from other works this review seeks to provide a holistic perspective of ammonia as a chemical that presents benefits and constraints for storing energy from sustainable sources. State-of-the-art knowledge provided by academics actively engaged with the topic at various fronts also enables a clear vision of the progress in each of the branches of ammonia as an energy carrier. Further the fundamental boundaries of the use of the molecule are expanded to real technical issues for all potential technologies capable of using it for energy purposes legal barriers that will be faced to achieve its deployment safety and environmental considerations that impose a critical aspect for acceptance and wellbeing and economic implications for the use of ammonia across all aspects approached for the production and implementation of this chemical as a fueling source. Herein this work sets the principles research practicalities and future views of a transition toward a future where ammonia will be a major energy player.

The growing use of proton-exchange membrane fuel cells (PEMFCs) in hybrid propulsion systems is aimed at replacing traditional internal combustion engines and reducing greenhouse gas emissions. Effective power distribution between the fuel cell and the energy storage system (ESS) is crucial and has led to a growing emphasis on developing energy management systems (EMSs) to efficiently implement this integration. To address this goal this study examines the performance of a fuzzy logic rule-based strategy for a hybrid fuel cell propulsion system in a small hydrogenpowered passenger vessel. The primary objective is to optimize fuel efficiency with particular attention on reducing hydrogen consumption. The analysis is carried out under typical operating conditions encountered during a river trip. Comparisons between the proposed strategy with other approaches—control based optimization based and deterministic rule based—are conducted to verify the effectiveness of the proposed strategy. Simulation results indicated that the EMS based on fuzzy logic mechanisms was the most successful in reducing fuel consumption. The superior performance of this method stems from its ability to adaptively manage power distribution between the fuel cell and energy storage systems.