Applications & Pathways

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.