Applications & Pathways

With increasingly stringent maritime environmental regulations hybrid fuel cell ships have garnered significant attention due to their advantages in low emissions and high efficiency. However challenges related to the coordinated control of multi-energy systems and fuel cell degradation remain significant barriers to their practical implementation. This paper proposes an innovative multi-timescale energy management strategy that focuses on optimizing the lifespan decay synergy of fuel cells and lithium batteries. The study designs an attention-based CNN-LSTM hybrid model for power prediction and constructs a twostage optimization framework: The first stage employs Model Predictive Control (MPC) for long-term power planning to optimize equivalent hydrogen consumption while the second stage focuses on real-time power allocation considering both power source degradation and system operational efficiency. The simulation results demonstrate that compared to single-layer MPC and the Equivalent Consumption Minimization Strategy (ECMS) the proposed method exhibits significant advantages in reducing single-voyage costs minimizing differences in power source degradation rates and alleviating power source stress. The overall performance of this strategy approaches the global optimal solution obtained through Dynamic Programming comprehensively validating its superiority in simultaneously optimizing system economics and durability.

In this study we employ an optimization model to optimally design a self-sufficient independent of any imports and exports hydrogen infrastructure for Austria by 2030. Our approach integrates key hydrogen technologies within a detailed spatial investment and operation model – coupled with a European scale electricity market model. We focus on optimizing diverse infrastructure componentsincluding trailers pipelines electrolyzers and storages to meet Austria's projected hydrogen demand. To accurately estimate this demand in hourly resolution we combine existing hydrogen strategies and projections to account for developments in various industrial sectors consider demand driven by the transport sector and integrate hydrogen demand arising from its use in gas-powered plants. Accounting for the inherent uncertainty linked to such projections we run the analysis for two complementary scenarios. Our approach addresses the challenges of integrating large quantities of renewable hydrogen into a future energy system by recognizing the critical role of domestic production in the early market stages. The main contribution of this work is to address the gap in optimizing hydrogen infrastructure for effective integration of domestic renewable hydrogen production in Austria by 2030 considering sector coupling potentials optimal electrolyzer placement and the design of local hydrogen networks.

This review focuses on the energy structure of iron and steel production and a feasible development path for carbon reduction. The process path and feasible development direction of carbon emission reduction in the iron and steel industry have been analyzed from the perspective of the carbon–electricity–hydrogen ternary relationship. Frontier technologies such as “hydrogen replacing carbon” are being developed worldwide. Combining the high efficiency of microwave electric-thermal conversion with the high efficiency and pollution-free advantages of hydrogen-reducing agents may drive future developments. In this review a process path for “microwave + hydrogen” synergistic metallurgy is proposed. The reduction of magnetite powder by H2 (CO) in a microwave field versus in a conventional field is compared. The driving effect of the microwave field is found to be significant and the synergistic reduction effect of microwaves with H2 is far greater than that of CO.

As a versatile energy carrier hydrogen possesses tremendous potential to reduce greenhouse emissions and promote energy transition. Global interest in producing hydrogen from renewable energy sources and transporting storing and utilizing hydrogen is rising rapidly. However the high costs of producing clean hydrogen and the uncertain application scenarios for hydrogen energy result in its relatively limited utilization worldwide. It is necessary to find new promising technological paths to drive the development of hydrogen energy. As part of technological innovation emerging technologies have vital features such as prominent impact novelty relatively fast growth etc. Identifying emerging hydrogen-energy-related technologies is important for discovering innovation opportunities during the energy transition. Existing research lacks analysis of the characteristics of emerging technologies. Thus this paper proposes a method combining the latent Dirichlet allocation topic model and hydrogen-energy expert group decision-making. This is used to identify emerging hydrogen-related technology regarding two features of emerging technologies novelty and prominent impact. After data processing topic modeling and analysis the patent dataset was divided into twenty topics. Six emerging topics possess novelty and prominent impact among twenty topics. The results show that the current hotspots aim to promote the application of hydrogen energy by improving the performance of production catalysts overcoming the wide power fluctuations and large-scale instability of renewable energy power generation and developing advanced hydrogen safety technologies. This method efficiently identifies emerging technologies from patents and studies their development trends. It fills a gap in the research on emerging technologies in hydrogen-related energy. Research achievements could support the selection of technology pathways during the low-carbon energy transition.

This paper presents the application of an active energy management strategy to a hybrid system consisting of a proton exchange membrane fuel cell (PEMFC) battery and supercapacitor. The purpose of energy management is to control the battery and supercapacitor states of charge (SOCs) as well as minimizing hydrogen consumption. Energy management should be applied to hybrid systems created in this way to increase efficiency and control working conditions. In this study optimization of an existing model in the literature with different meta-heuristic methods was further examined and results similar to those in the literature were obtained. Ant lion optimizer (ALO) moth-flame optimization (MFO) dragonfly algorithm (DA) sine cosine algorithm (SCA) multi-verse optimizer (MVO) particle swarm optimization (PSO) and whale optimization algorithm (WOA) meta-heuristic algorithms were applied to control the flow of power between sources. The optimization methods were compared in terms of hydrogen consumption and calculation time. Simulation studies were conducted in Matlab/Simulink R2020b (academic license). The contribution of the study is that the optimization methods of ant lion algorithm moth-flame algorithm and sine cosine algorithm were applied to this system for the first time. It was concluded that the most effective method in terms of hydrogen consumption and computational burden was the sine cosine algorithm. In addition the sine cosine algorithm provided better results than similar meta-heuristic algorithms in the literature in terms of hydrogen consumption. At the same time meta-heuristic optimization algorithms and equivalent consumption minimization strategy (ECMS) and classical proportional integral (PI) control strategy were compared as a benchmark study as done in the literature and it was concluded that meta-heuristic algorithms were more effective in terms of hydrogen consumption and computational time.

Interest in more sustainable energy sources has increased rapidly in the maritime industry and ambitious goals have been set for decreasing ship emissions. All industry stakeholders have reacted to this with different approaches including the optimisation of ship power plants the development of new energy-improving sub-systems for existing solutions or the design of entirely novel power plant concepts employing alternative fuels. This paper assesses the feasibility of different ship energy sources for an icebreaking Arctic research ship. To that end possible energy sources are assessed based on fuel infrastructure availability and operational endurance criteria in the operational area of interest. Promising alternatives are analysed further using the evidence-based Strengths Weaknesses Opportunities and Threats (SWOT) method. Then a more thorough investigation with respect to the required fuel tank space life cycle cost and CO2 emissions is implemented. The results demonstrate that marine diesel oil (MDO) is currently still the most convenient solution due to the space operational range and endurance limitations although it is possible to use liquefied natural gas (LNG) and methanol if the ship’s arrangement is radically redesigned which will also lead to reduced emissions and life cycle costs. The use of liquefied hydrogen as the only energy solution for the considered vessel was excluded from the potential options due to low volumetric energy density and high life cycle and capital costs. Even if it is used with MDO for the investigated ship the reduction in CO2 emissions will not be as significant as for LNG and methanol at a much higher capital and lifecycle cost. The advantage of the proposed approach is that unrealistic alternatives are eliminated in a systematic manner before proceeding to detailed techno-economic analysis facilitating the decision-making and investigation of various options in a more holistic manner.

Over 35% of the CO2 associated with cement production comes from operational energy. The cement industry needs alternative fuels to meet its net zero emissions target. This study investigated the influence of hydrogen mixed with biofuels herein designated net zero fuel as an alternative to coal on the clinker quality and performance of cement produced in an industrial cement plant. Scanning electron microscopy X-ray diffraction and nuclear magnetic resonance were coupled to study the clinker mineralogy and polymorphs. Hydration and microstructure development in plain and slag blended cements based on the clinker were compared to commercial cement equivalent. The results revealed a lower alite/belite ratio but a significant proportion of the belite was of the α’H-C2S polymorph. These reacted faster and compensated for the alite/belite ratio. Gel and micro-capillary pores were densified which reduced total porosity and attained comparable strength to the reference plain and blended cement. This study demonstrates that the investigated net zero fuel-produced clinker meets compositional and strength requirements for plain and blended cement providing a feasible pathway for the cement industry to lower its operational carbon significantly.

Steel production is a highly energy-intensive industry responsible for significant greenhouse gas emissions. Electrification of this sector is challenging making green hydrogen technology a promising alternative. This research performs a thermodynamic analysis of green hydrogen production for steel manufacturing using the direct reduction method. Four solid oxide electrolyzer (SOE) modules replace the traditional reformer to produce 2.88 kg/s of hydrogen gas serving as a reducing agent for iron pellets to yield 30 kg/s of molten steel. These modules are powered by 37801 photovoltaic units. Additionally a thermal storage system utilizing 1342 tons of steel slag stores waste heat from Electric Arc Furnace (EAF) exhaust gases. This stored energy preheats iron scraps charged into the EAF reducing energy consumption by 5%. A life cycle assessment conducted using open LCA software reveals that the global warming potential (GWP) for the entire process with a capacity of 30 kg/s equates to 93 kg of CO2. The study also assesses other environmental impacts such as acidification potential ozone formation fine particle formation and human toxicity. Results indicate that the EAF significantly contributes to global warming and fine particle formation while the direct reduction process notably impacts ozone formation and acidification potential.

The paper discusses some of the requirements drivers and resulting technological paths for manufacturers to develop hydrogen combustion engines for use in two types of market application – onroad heavy- and light-duty. One of the main requirements is legislative certainty and this has now been afforded – at least in the major market of Europe – by the European Union’s recent adoption into law of tailpipe emissions limits specifically designed to encourage the uptake of hydrogen engines in heavy-duty vehicles giving manufacturers the confidence they need to invest in productionized solutions to offer to customers. It then discusses combustion systems and boosting systems for the two market types emphasizing that heavy-duty vehicles need best efficiency throughout their operating map while light-duty ones since they are rarely operated at full load will mainly primarily need efficiency in the part-load region. This difference will likely cause a divergence in solutions with heavy-duty engines running very lean everywhere and light-duty ones likely operating at the stoichiometric air-fuel ratio at least for most of the map. The impacts of the strategies on engine systems and vehicle integration are discussed. It is postulated that due to reasons of preignition avoidance and efficiency hydrogen engines will rapidly adopt direct injection and that the long-term heavy-duty types will migrate towards the typical current spark-ignition-type cylinder head architecture where tumble rather than swirl will ultimately be needed for air motion in the cylinder for these reasons. They may also adopt active pre-chamber technology to ignite extremely lean mixtures for maximum efficiency and minimum emissions of oxides of nitrogen. It is suggested that light-duty engines will evolve less from their current gasoline architectural norm since they already contain all of the necessary fundamentals for hydrogen combustion. However since partload efficiency will be important some new strategies may become desirable. Developing dual-fuel light-duty engines could accelerate their uptake as the heavy-duty market simultaneously accelerates the creation of the fuel supply infrastructure. The likely technological evolution suggests that variable valve trains and specifically cam profile switching technology would be extremely useful for all types of hydrogen engine especially since they are readily available in different gasoline engines now. New operating strategies afforded by variable valve trains would benefit both heavy- and light-duty engines and these strategies will become more sophisticated. There will therefore likely be a convergence of technologies for the two markets albeit with some key differences maintained due to their vehicle applications and their differing operation in the field.

Hybrid hydrogen-battery powertrains represent a promising solution for sustainable transport. In these systems a fuel cell converts hydrogen into electricity to power the motors and charge a battery which in turn manages power fluctuations and enables regenerative braking. This study investigates degradation in hybrid powertrain components for the railway sector focusing on optimizing their operation to enhance durability. The analysis applied to a real case study on a non-electrified railway line in northern Italy evaluates different operating strategies by constraining the fuel cell current ramp. The results show that operating the fuel cell with minimal power fluctuations – while relying on the battery to handle power peaks – offers a clear advantage. Specifically reducing the maximum fuel cell current ramp from 1500 A/s (load-following operation) to 1 A/s (near-constant operation) extends fuel cell lifetime by 50.5 % though at the expense of a 25.1 % reduction in battery lifetime.