Applications & Pathways

Even if the aviation sector only accounts for 2% of global energy-related CO2 emissions and is the most challenging sector to decarbonize. As aviation demand grows and the need for sustainable jet fuels becomes urgent green hydrogen could substitute conventional fossil fuels thereby enabling carbon-free flights. This study investigates a techno-economic analysis of onsite versus off-site green hydrogen supply chains. A case study at the Toulouse-Blagnac airport (Europe’s first station for the production and distribution of renewable hydrogen) in France is developed to meet commercial aviation's hydrogen fuel demand between 2025 and 2050. Demand of hydrogen is projected based on the trend of jet fuel consumption. First the cost of solar-based renewable electricity is estimated at the two green hydrogen production sites using levelized cost of electricity production. Second levelized cost of hydrogen (LCOH) is evaluated for three value chain scenarios: one on-site (Toulouse airport) and two off-site (Marseille) for gaseous and cryogenic transportation of liquid hydrogen (LH2). A relative cost advantage is shown for the off-site case with cryogenic truck transportation at LCOH of €9.43/kg.LH2. This study also reveals the importance of electricity price investment costs operation costs economies of scale and transportation distance in different scenarios.

In the pursuit of establishing a sustainable fuel cell (FC) energy system this review highlights the necessity of examining the operational principles technical details environmental consequences and economic concerns collectively. By adopting an integrated approach the review research into various fuel cells types extending their applications beyond transportation and evaluating their potential for seamless integration into sustainable practices. A detailed analysis of the technical aspects including FC membranes performance and applications is presented. The environmental impact of hydrogen generation through fuel cell/electrolyzer is quantitatively assessed emphasizing a comparative emission footprint against traditional hydrogen generation methods. Economic considerations of fuel cell technology adoption are explored through an extensive examination of market growth and forecasts and investments into the FC systems. Some flagship commercial projects of FC technology are also discussed along with their future prospective. The article concludes with a thorough analysis of challenges associated with FC adoption encompassing membrane research performance hurdles infrastructure development and application-specific challenges. This all-round review serves as an indispensable tool for academicians and policymakers providing a directed and comprehensive FC perspective.

In the context of “dual carbon” in order to promote the consumption of renewable energy and improve energy utilization efficiency a low-carbon economic dispatch model of an integrated energy system containing carbon capture power plants and multiple utilization of hydrogen energy is proposed. First introduce liquid storage tanks to transform traditional carbon capture power plants and at the same time build a multi-functional hydrogen utilization structure including two-stage power-to-gas hydrogen fuel cells hydrogen storage tanks and hydrogen-doped cogeneration to fully exploit hydrogen. It can utilize the potential of collaborative operation with carbon capture power plants; on this basis consider the transferability and substitutability characteristics of electric heating gas load and construct an electric heating gas comprehensive demand response model; secondly consider the mutual recognition relationship between carbon quotas and green certificates Propose a green certificate-carbon trading mechanism; finally establish an integrated energy system with the optimization goal of minimizing the sum of energy purchase cost demand response compensation cost wind curtailment cost carbon storage cost carbon purchase cost carbon trading cost and green certificate trading compensation. Optimize scheduling model. The results show that the proposed model can effectively reduce the total system cost and carbon emissions improve clean energy consumption and energy utilization and has significant economical and low-carbon properties.

Hydrogen-fueled Internal Combustion Engines (H2-ICEs) are typically operated with lean mixtures to minimize NOx emissions and reduce the risk of abnormal combustion events. Due to hydrogen’s low Lewis number premixed hydrogen-air flames in lean conditions exhibit strong thermodiffusive instabilities which make the numerical simulation of the combustion process particularly challenging. Indeed the intensity of these instabilities is significantly influenced by thermodynamic parameters – such as mixture temperature pressure and dilution rate – resulting in substantial variations in combustion behaviour across different operating conditions. Therefore they have to be properly considered not only to ensure model robustness but also to improve model accuracy over a wider range of operations. In this study the combustion process in a Direct Injection H2-ICE was analyzed using 3D-CFD simulations relying on a flamelet-based combustion model. Two sets of lookup flame speed maps were defined: laminar flame speed (SL) maps derived from standard 1D-CFD simulations in homogeneous reactor and freely propagating flame speed (SM) maps which account for the effects of thermodiffusive instabilities. The model that uses SL maps required the recalibration of some combustion model parameters when changing the dilution rate to ensure consistency with experimental data. Instead the model relying on SM maps featured a noticeable accuracy across different air-to-fuel ratios without the need for recalibration any combustion model parameter highlighting the key role of thermodiffusive flame instabilities on the combustion process. Based on these findings the impact of such instabilities was evaluated throughout the entire combustion process from both global and local perspectives. The relevance of thermodiffusive instabilities was observed to increase with the air-to-fuel ratio thereby enhancing combustion speed in leaner mixtures. Additionally the implementation of thermodiffusive instabilities was found to affect also preferred direction of flame propagation as stronger instabilities were identified in the leanest and low-temperature portions of the flame front. Novelty and significance This study addresses a critical knowledge gap regarding the role of thermodiffusive flame instabilities in accurately replicating the combustion process of a direct-injection internal combustion engine within a RANS simulation framework. Indeed while these instabilities have been shown to significantly enhance the mixture consumption rate in quiescent environments at low to moderate pressures and temperatures particularly in lean mixtures their impact on the burn rate under engine-like conditions has not yet been systematically investigated to the best of the authors’ knowledge. This work provides a comprehensive analysis of the significance of these instabilities in the combustion process of a direct-injection hydrogen internal combustion engine. The analysis is conducted from both a global perspective assessing their overall influence on the combustion process and a local perspective examining how they alter flame front characteristics when incorporated into the model.

Research into the off-grid hybrid energy system to provide reliable electricity to a remote community has extensively been done. However simultaneous meeting electric freshwater and gas demands from the off-grid hybrid energy sources are very scarce in literature. Power- to-X (PtX) is gaining attention in recent days in the energy transition scenarios to generate green hydrogen the primary product of the process as an energy carrier which is deemed to replace conventional fuels to reach absolute carbon neutrality. In this study renew able–based hybrid energy is developed to simultaneously meet the electricity freshwater and gas (cooking gas via methanation process) demands for a remote Island in Bangladesh. In this process an energy management strategy has been developed to use the excess energy to generate both freshwater and the hydrogen where hydrogen is then converted to natural gas via methanation process. The PV wind turbine diesel generator battery and fuel cell have been optimized using non-dominating sorting algorithm-II (NSGA-II) to offer reliable cost-effective solutions of electricity freshwater and cooking gas for the end users. Results reported that the PV/ WT/DG/Batt configuration has been found the most economic configuration with the lowest COE (0.1724 $/kWh) which is 9 % lower than PV/WT/Batt configuration which has the second lowest COE. The cost of water (COW) and cost of gas (COG) of the PV/WT/DG/Batt system are also the lowest among all the four configurations and have been found 1.185 $/m3 and 3.978 $/m3 respectively.

This research designs a conceptual system where both solar and biomass energy subsystems are uniquely integrated to turn wastewater into useful outputs such as hydrogen fresh water and heat to achieve sustainable communities where renewable energy is utilized with the wastewater treated effectively. The system integrates several subsystems including a reheat Rankine cycle an organic Rankine cycle a multi-stage flash desalination system and a biohydrogen production unit employing a microbial electrolysis process. In order to study a potential application of this conceptually developed system the city of Oshawa in Ontario Canada is identified with its wastewater treatment facility which is designed to produce clean biohydrogen that is liquefied and stored for distribution to refueling stations for hydrogen-based transportation. In this regard thermodynamic analysis and assessment studies are conducted using the Engineering Equation Solver and demonstrating that the system achieves the overall energetic and exergetic efficiencies of 34.94% and 32.84% respectively. Furthermore the system produces freshwater at a rate of 5.36 kg/s and biohydrogen at 0.03 kg/s contributing to environmental sustainability and efficient resource utilization in addition to the heat recovered and used in the community as a useful output. This research highlights the potential of the system to significantly reduce greenhouse gas emissions while promoting sustainable energy and transportation developments in Oshawa and similar regions.

In recent years numerous hydrogen-powered rail vehicles have been developed and their deployment within public transport is steadily increasing. To avoid disadvantages compared to diesel vehicles refueling times of 15 min are stated in the industry as target independent of climate zones or vehicle configurations. As refueling time varies with these parameters this work presents the corresponding refueling times and defines optimization potentials. A simulation model was set up and parametrized with a reference vehicle and hydrogen refueling station from the FCH2RAIL project. Measurement data from this station and vehicle were analyzed and compared to simulation results for model validation. The results show that at high ambient temperature pre-cooling reduces refueling time by 71 % and type 4 tanks increase refueling time by 20 % compared to type 3. Overall optimized tank design and thermal management reduce the refueling time for rail vehicles from over 2 h to 15 min.

The UK has set an ambitious target of delivering clean power by 2030. Low carbon dispatchable power generation using hydrogen will play a key role in a clean power system by providing flexibility and other services for system operability and also by providing supply adequacy during extended periods of low renewable output decarbonising the role currently performed by an aging portfolio of unabated natural gas power generation. While some 100% hydrogen to power (H2P) commercial projects are already being deployed globally using multi megawatt fuel cells alongside blending hydrogen into existing gas turbines and new hydrogen ready turbines industrial scale 100% H2P projects face additional challenges of deploying new technology into a nascent system one which requires significant volumes of hydrogen storage with long lead times. To achieve the 2030 clean power system ambition and lay the foundations for a clean resilient and secure power system beyond 2030 it is critical that the new government takes resolute actions now to support H2P at scale. A clear strategic plan should be developed within the first 12 months of the new administration with clarity being given on policy business models and deployment rates for hydrogen to power (H2P) and its enabling infrastructure. This report produced by Hydrogen UK’s Power Generation Working Group explores the role that H2P will play in the decarbonised power system of the future the barriers to deployment and recommendations for overcoming them.

This paper can be found on their website.

This study investigates the effects of secondary jet-guided combustion on the combustion and emissions of a hydrogen direct-injection engine through numerical simulations. The results show that secondary jet-guided combustion which involves injecting and igniting the hydrogen jet at the end of the compression stroke significantly shortens the delay period improves combustion stability and brings the combustion center closer to the top dead center (TDC) achieving a maximum indicative thermal efficiency (ITE) of 46.55% (λ = 2.4). However this strategy results in higher NOx emissions due to high-temperature combustion. In contrast single and double injections lead to worsened combustion and reduced thermal efficiency under lean-burn conditions but with relatively lower NOx emissions. This study demonstrates that secondary jet-guided combustion can effectively enhance hydrogen engine performance by optimizing mixture stratification and flame propagation providing theoretical support for clean and efficient combustion.

Hydrogen fuel presents a promising pathway for achieving long-term decarbonization in the maritime sector. However its use in diesel engines introduces challenges due to high reactivity leading to increased NOx emissions and combustion instability. The aim of this study is to identify settings so that the investigated engine operates with 60% hydrogen energy fraction at high load through CFD modelling. The model is utilized to simulate a four-stroke 10.5 MW marine engine at 90% load incorporating 60% hydrogen injection by energy at the engine intake port. The CFD model is verified using experimental data from diesel operation of the marine engine and hydrogen operation of a light-duty engine. The engine performance was determined and detailed emissions analysis was conducted including NO NO2 HO2 and OH. The findings indicate a substantial rise in NOx emissions as opposed to diesel operation due to elevated combustion temperatures and increased residence time at elevated temperature of the mixture in-cylinder. The presence of HO2 and OH highlights critical zones of combustion which contribute to operational stability. The novelty of this study is supported by the examination of the high hydrogen energy fraction the advanced emissions analysis and the insights into the emissions–performance trade-offs in hydrogen-fueled dual-fuel marine engines. The results offer guidance for the development of sustainable hydrogen-based marine propulsion systems.