Publications

Blending hydrogen with natural gas (NG) is an efficient method for transporting hydrogen on a large scale at a low cost. The manifold at the NG initial station is an important piece of equipment that enables the blending of hydrogen with NG. However there are differences in the components and component contents of imported NG from different countries. The components of hydrogen-blended NG can affect the safety and efficiency of transportation through pipeline systems. Therefore numerical simulations were performed to investigate the blending process and changes in the thermodynamic properties of four imported NGs and hydrogen in the manifold. The higher the heavy hydrocarbon content in the imported NG the longer the distance required for the gas to mix uniformly with hydrogen in the pipeline. Hydrogen blending reduces the temperature and density of NG. The gas composition is the main factor affecting the molar calorific value of a gas mixture and hydrogen blending reduces the molar calorific value of NG. The larger the content of high-molar calorific components in the imported NG the higher the molar calorific value of the gas after hydrogen blending. Increasing both the temperature and hydrogen mixing ratio reduces the Joule-Thomson coefficient of the hydrogen-blended NG. The results of this study provide technical references for the transport of hydrogen-blended NG.

In the quest for a sustainable future energy-intensive industries (EIIs) stand at the forefront of Europe’s decarbonisation mission. Despite their significant emissions footprint the path to comprehensive decarbonisation remains elusive at EU and national levels. This study scrutinises key sectors such as non-ferrous metals steel cement lime chemicals fertilisers ceramics and glass. It maps out their current environmental impact and potential for mitigation through innovative strategies. The analysis spans across Spain Greece Germany and the Netherlands highlighting sector-specific ecosystems and the technological breakthroughs shaping them. It addresses the urgency for the industry-wide adoption of electrification the utilisation of green hydrogen biomass bio-based or synthetic fuels and the deployment of carbon capture utilisation and storage to ensure a smooth transition. Investment decisions in EIIs will depend on predictable economic and regulatory landscapes. This analysis discusses the risks associated with continued investment in high-emission technologies which may lead to premature decommissioning and significant economic repercussions. It presents a dichotomy: invest in climate-neutral technologies now or face the closure and offshoring of operations later with consequences for employment. This open discussion concludes that while the technology for near-complete climate neutrality in EIIs exists and is rapidly advancing the higher costs compared to conventional methods pose a significant barrier. Without the ability to pass these costs to consumers the adoption of such technologies is stifled. Therefore it calls for decisive political commitment to support the industry’s transition ensuring a greener more resilient future for Europe’s industrial backbone.

The urgent need to tackle climate change drives the research on new technologies to help the transition of energy systems. Hydrogen is under significant consideration by many countries as a means to reach zero-carbon goals. Turkey has also started to develop hydrogen projects. In this study the role of hydrogen in Turkey’s energy system is assessed through energy modeling using the cost optimization analytical tool Open Source Energy Modelling System (OSeMOSYS). The potential effects of hydrogen blending into the natural gas network in the Turkish energy system have been displayed by scenario development. The hydrogen is produced via electrolysis using renewable electricity. As a result by using hydrogen a significant reduction in carbon dioxide emissions was observed; however the accumulated capital investment value increased. Furthermore it was shown that hydrogen has the potential to reduce Turkey’s energy import dependency by decreasing natural gas demand.

Fuel cell hybrid electric vehicles have the advantages of zero emission high efficiency and fast refuelling etc. and are one of the key directions for vehicle development. The energy management problem of fuel cell hybrid electric vehicles is the key technology for power distribution. The traditional power following strategy has the advantage of a real-time operation but the power correction is usually based only on the state of charge of a lithium battery which causes the operating point of the fuel cell to be in the region of a low efficiency. To solve this problem this paper proposes a hybrid power-following-fuzzy control strategy where a fuzzy logic control strategy is used to optimise the correction module based on the power following strategy which regulates the state of charge while correcting the output power of the fuel cell towards the efficient operating point. The results of the joint simulation with Matlab + Advisor under the Globally Harmonised Light Vehicle Test Cycle Conditions show that the proposed strategy still ensures the advantages of real-time energy management and for the hydrogen fuel cell the hydrogen consumption is reduced by 13.5% and 4.1% compared with the power following strategy and the fuzzy logic control strategy and the average output power variability is reduced by 14.6% and 5.1% respectively which is important for improving the economy of the whole vehicle and prolonging the lifetime of fuel cell.

The safety engineering design of hydrogen systems and infrastructure worker education and training regulatory compliance and engagement with other stakeholders are significant to the viability and public acceptance of hydrogen farms. The only way to ensure these are accomplished is for the field of hydrogen safety engineering (HSE) to grow and mature. HSE is described as the application of engineering and scientific principles to protect the environment property and human life from the harmful effects of hydrogen-related mishaps and accidents. This paper describes a whole hydrogen farm that produces hydrogen from seawater by alkaline and proton exchange membrane electrolysers then details how the hydrogen gas will be used: some will be stored for use in a combined-cycle gas turbine some will be transferred to a liquefaction plant and the rest will be exported. Moreover this paper describes the design framework and overview for ensuring hydrogen safety through these processes (production transport storage and utilisation) which include legal requirements for hydrogen safety safety management systems and equipment for hydrogen safety. Hydrogen farms are large-scale facilities used to create store and distribute hydrogen which is usually produced by electrolysis using renewable energy sources like wind or solar power. Since hydrogen is a vital energy carrier for industries transportation and power generation these farms are crucial in assisting the global shift to clean energy. A versatile fuel with zero emissions at the point of use hydrogen is essential for reaching climate objectives and decarbonising industries that are difficult to electrify. Safety is essential in hydrogen farms because hydrogen is extremely flammable odourless invisible and also has a small molecular size meaning it is prone to leaks which if not handled appropriately might cause fires or explosions. To ensure the safe and dependable functioning of hydrogen production and storage systems stringent safety procedures are required to safeguard employees infrastructure and the surrounding environment from any mishaps.

Decarbonising energy systems is a prevalent topic in the current literature on climate change mitigation but the additional climate burden caused by methane emissions along the natural gas value chain is rarely discussed at the system level. Considering a two-basket greenhouse gas neutrality objective (both CO2 and methane) we model cost-optimal European energy transition pathways towards 2050. Our analysis shows that adoption of best available methane abatement technologies can entail an 80% reduction in methane leakage limiting the additional environmental burden to 8% of direct CO2 emissions (vs. 35% today). We show that while renewable energy sources are key drivers of climate neutrality the role of natural gas strongly depends on actions to abate both associated CO2 and methane emissions. Moreover clean hydrogen (produced mainly from renewables) can replace natural gas in a substantial proportion of its end-uses satisfying nearly a quarter of final energy demand in a climate-neutral Europe.

Hydrogen has the capability of being a potential energy carrier and providing a long-term solution for sustainable lower-carbon and ecologically benign fuel supply. Because lower-carbon hydrogen is widely used in chemical synthesis it is regarded as a fuel with no emissions for transportation. This review paper offers a novel technique for producing hydrogen using wastewater in a sustainable manner. The many techniques for producing hydrogen with reduced carbon emissions from wastewater are recognized and examined in detail taking into account the available prospects significant obstacles and potential future paths. A comparison of the assessment showed that water electrolysis and dark fermentation technologies are the most effective methods for hydrogen generation from wastewater with microbial electrolysis and photofermentation. Thus the incorporation of systems that are simultaneously producing lower-carbon hydrogen and meant for wastewater treatment is important for the minimization of emissions from greenhouse gases and recovering the energy utilized in the treatment of wastewater.

This narrative document sets out the main rationale for hydrogen storage development at scale in the UK: - To meet net zero the UK will need considerable energy storage - Hydrogen storage will be a major and essential part of this - Physical hydrogen storage is needed in the UK - Only geological hydrogen storage can deliver at the scale needed within the timescales for net zero - Geological hydrogen storage should be supported through a viable business model now to ensure it comes online in the 2030s.

Climatic changes are reaching alarming levels globally seriously impacting the environment. To address this environmental crisis and achieve carbon neutrality transitioning to hydrogen energy is crucial. Hydrogen is a clean energy source that produces no carbon emissions making it essential in the technological era for meeting energy needs while reducing environmental pollution. Abundant in nature as water and hydrocarbons hydrogen must be converted into a usable form for practical applications. Various techniques are employed to generate hydrogen from water with solar hydrogen production—using solar light to split water—standing out as a cost-effective and environmentally friendly approach. However the widespread adoption of hydrogen energy is challenged by transportation and storage issues as it requires compressed and liquefied gas storage tanks. Solid hydrogen storage offers a promising solution providing an effective and low-cost method for storing and releasing hydrogen. Solar hydrogen generation by water splitting is more efficient than other methods as it uses self-generated power. Similarly solid storage of hydrogen is also attractive in many ways including efficiency and cost-effectiveness. This can be achieved through chemical adsorption in materials such as hydrides and other forms. These methods seem to be costly initially but once the materials and methods are established they will become more attractive considering rising fuel prices depletion of fossil fuel resources and advancements in science and technology. Solid oxide fuel cells (SOFCs) are highly efficient for converting hydrogen into electrical energy producing clean electricity with no emissions. If proper materials and methods are established for solar hydrogen generation and solid hydrogen storage under ambient conditions solar light used for hydrogen generation and utilization via solid oxide fuel cells (SOFCs) will be an efficient safe and cost-effective technique. With the ongoing development in materials for solar hydrogen generation and solid storage techniques this method is expected to soon become more feasible and cost-effective. This review comprehensively consolidates research on solar hydrogen generation and solid hydrogen storage focusing on global standards such as 6.5 wt% gravimetric capacity at temperatures between −40 and 60 ◦C. It summarizes various materials used for efficient hydrogen generation through water splitting and solid storage and discusses current challenges in hydrogen generation and storage. This includes material selection and the structural and chemical modifications needed for optimal performance and potential applications.

Hydrogen component reliability and the hazard associated with failure rates is a critical area of research for the successful implementation and growth of hydrogen technology across the globe. The research team has partnered to quantify system risk reduction through earlier detection of hydrogen component failures. A model of hydrogen dispersion in a hydrogen equipment enclosure has been developed utilizing experimentally quantified hydrogen component leak rates as inputs. This model provides insight into the impact of hydrogen safety sensors and ventilation on the flammable mass within a hydrogen equipment enclosure. This model also demonstrates the change in safety sensor response time due to detector placement under various leak scenarios. The team looks to improve overall hydrogen system safety through an improved understanding of hydrogen component reliability and risk mitigation methods. This collaboration fits under the work program of IEA Hydrogen Task 43 Subtask E Hydrogen System Safety.

Due to the privileged location of Ecuador in terms of solar radiation the analysis and use of renewable energy system (RES) using solar energy has been of great interest during the last years. At the same time the supply support of RES in terms of direct current (DC) can be faced by using fuel cell (FC) systems which can give to the systems fully autonomy from fossil fuels. The aim of this paper is to propose the design of a hybrid photovoltaic-fuel cell-battery (PV-FC-B) system to supply the required electrical energy for residential use in the city of Guayaquil. The feasibility analysis constitutive elements of the system and adjusted variables are computed and presented using a computational tool. The results evidence that this system is not economically viable since the cost of energy (COE) in Ecuador is low compared to the COE of the proposed system. However a more detailed analysis considering the inherent benefits of no emission of pollutant gases is required to have a complete outlook.

This paper presents the “Three Gorges Hydrogen Boat No. 1” a novel green hydrogen-powered vessel that has been successfully delivered and is currently sailing. This vessel integrated with a hydrogen production and bunkering station at its dedicated dock achieves zero-carbon emissions. It stores 240 kg of 35 MPa gaseous hydrogen and has a fuel cell system rated at 500 kW. We analysed the engineering details of the marine hydrogen system including hydrogen bunkering storage supply fuel cell and the hybrid power system with lithium-ion batteries. In the first bunkering trial the vessel was safely refuelled with 200 kg of gaseous hydrogen in 156 min via a bunkering station 13 m above the water surface. The maximum hydrogen pressure and temperature recorded during bunkering were 35.05 MPa and 39.04 ◦C respectively demonstrating safe and reliable shore-toship bunkering. For the sea trial the marine hydrogen system operated successfully during a 3-h voyage achieving a maximum speed of 28.15 km/h (15.2 knots) at rated propulsion power. The vessel exhibited minimal noise and vibration and its dynamic response met load change requirements. To prevent rapid load changes to the fuel cells 68 s were used to reach 483 kW from startup and 62 s from 480 kW to zero. The successful bunkering and operation of this hydrogen-powered vessel demonstrates the feasibility of zero-carbon emission maritime transport. However four lessons were identified concerning bunkering speed hydrogen cylinder leakage hydrogen pressure regulator malfunctions and fuel cell room space. The novelty of this work lies in the practical demonstration of a fully operational hydrogen-powered maritime vessel achieving zero emissions encompassing its design building operation and lessons learned. These parameters and findings can be used as a baseline for further engineering research.

Geological structures in deep aquifers and salt caverns can play an important role in large-scale hydrogen storage. However more work needs to be done to address the hydrogen storage demand for zero-emission energy systems. Thus the aim of the article is to present the demand for hydrogen storage expressed in the number of salt caverns in bedded rock salt deposits and salt domes or the number of structures in deep aquifers. The analysis considers minimum and maximum hydrogen demand cases depending on future energy system configurations in 2050. The method used included the estimation of the storage capacity of salt caverns in bedded rock salt deposits and salt domes and selected structures in deep aquifers. An estimation showed a large hydrogen storage potential of geological structures. In the case of analyzed bedded rock salt deposits and salt domes the average storage capacity per cavern is 0.05–0.09 TWhH2 and 0.06–0.20 TWhH2 respectively. Hydrogen storage capacity in analyzed deep aquifers ranges from 0.016 to 4.46 TWhH2. These values indicate that in the case of the upper bound for storage demand there is a need for the 62 to 514 caverns depending on considered bedded rock salt deposits and salt domes or the 9 largest analyzed structures in deep aquifers. The results obtained are relevant to the discussion on the global hydrogen economy and the methodology can be used for similar considerations in other countries.

The desire to maintain CO2 concentrations in the global atmosphere implies the need to introduce ’new’ energy carriers for transport applications. Therefore the operational consumption of each such potential medium in the ’natural’ exploitation of vehicles must be assessed. A useful assessment method may be the vehicle’s energy footprint resulting from the theory of cumulative fuel consumption presented in the article. Using a (very modest) database of long-term use of hydrogen-powered cars the usefulness of this method was demonstrated. Knowing the energy footprint of vehicles of a given brand and type and the statistical characteristics of the footprint elements it is also possible to assess vehicle fleets in terms of energy demand. The database on the use of energy carriers such as hydrogen in the long-term operation of passenger vehicles is still relatively modest; however as it has been shown valuable data can be obtained to assess the energy demand of vehicles of a given brand and type. Access to a larger operational database will allow for wider use of the presented method.

This project an essential part of the National Gas HyNTS programme endeavours to align the NTS with GB’s net zero ambitions by demonstrating the operational viability of the system with varying hydrogen blends using decommissioned assets typical of the natural gas network today ultimately aiming for 100% hydrogen conveyance. Several desktop studies were undertaken within the HyNTS programme to confirm the theoretical potential of the NTS to transport hydrogen safely and reliably. Further to these studies practical demonstration was deemed necessary to bridge the knowledge gaps and ensure the system’s transition maintains the utmost safety and reliability standards. A range of tests on decommissioned assets were conducted offline in a controlled environment to ensure robust outcomes that will ultimately start to build the safety case for a hydrogen network. The key deliverables and testing achievements of FutureGrid included: • Operational testing with natural gas and 2% 5% 20% and 100% hydrogen to verify the network’s ability to transport hydrogen and varying blends. • Standalone offline testing modules complementing evidence gathered on the main test facility. These address specific areas of concern including material permeation flange integrity asset leakage and rupture consequence which are essential for risk mitigation and safety assurance. FutureGrid is a global first facility and a critical part of National Gas’ hydrogen programme providing physical evidence of the capability of our network to transport hydrogen. It provides key evidence for hydrogen blending alongside 100% hydrogen pipelines which are planned under Project Union our Hydrogen Backbone across GB. FutureGrid is pivotal in the journey to reaching Net Zero by 2050 and is a fully operational proven technical demonstrator. FutureGrid’s repurposed assets are representative of today’s live high pressure gas network and have been subjected to testing at different blends of natural gas with hydrogen and 100% hydrogen; this was achieved with no major findings in differences in terms of how the assets interact with hydrogen. The overall project completion date was delayed from November 2023 to February 2024 due to technical issues with the newly built hydrogen re‑compressor. There were no changes made to the project costs.

This article analyzes and compares three methodologies for identifying suitable regions for solar hydrogen production using photovoltaic panels: AHP (Analytic Hierarchy Process) FAHP (Fuzzy Analytic Hierarchy Process) and MC-FAHP (Monte Carlo FAHP) integrated with GIS (Geographic Information Systems). The study employs ten criteria across technical (Global Horizontal Irra diance temperature slope elevation orientation) economic (distance from transportation and electrical networks) and social (population density proximity to residential areas) factors. Environmental and exclusion criteria define restrictive zones. The analysis reveals that while all three methods agree on areas of low suitability they diverge in their classification of "Suitable" "Highly Suitable" and "Most Suitable" regions. FAHP identifies 229.573 km2 as "Highly Suitable" compared to AHP’s 222.048 km2 and MC-FAHP’s 230.299 km2 for "Suitable" areas. Despite these differences the energy potential is consistent across methods totaling around 79000 TWh/year with MC-FAHP estimating the highest hydrogen production potential at 1.51 billion tons/year. The study concludes that fuzzy-based methods (FAHP and MC-FAHP) better handle uncertainties than traditional AHP. The MC-FAHP method in particular performs well in managing stochastic variability and yielding more reliable results. The findings are validated through a case study in Guider and Maroua highlighting the importance of socio-economic and environmental criteria in decision-making. A sensitivity analysis reveals that economic and social criteria significantly influence land suitability underscoring the importance of criteria selection in decision-making.

The significant growth of both the global population and economy in recent years has led to a rise in global energy demand. Fossil fuels have a significant contribution to generating energy which has raised concerns about sustainability and environmental impact. There are widespread efforts to find alternative sources in order to reduce dependence on fossil fuels and mitigate their environmental consequences. Among the alternative sources hydrogen has emerged as a promising option due to its potential to be a clean and sustainable energy source. Hydrogen possesses several advantages such as a high calorific value a high reaction rate various sources and the ability to integrate with other renewable energy sources and existing systems. These attributes render hydrogen a stable and reliable energy resource which can help reduce greenhouse gas emissions (GHG) and transition towards a sustainable future. In this review paper distinct hydrogen production technologies such as conventional renewable and nuclear energy are investigated and compared. In addition the challenges and limitations of the application of hydrogen fuel cells on vehicles and hydrogen circulation components are explored. Finally the environmental impact of hydrogen vehicles specifically their role in promoting sustainable development is investigated.

This week’s episode is a discussion between EAH hosts Patrick Molloy Alicia Eastman and Chris Jackson. The team cover the current status of hydrogen regulation innovation financing markets and consolidation. Hanging over most conversations in the decarbonization or future fuels space is the perpetual question: When will investors actually step up with significant capital to help companies make it through the development desert instead of letting promising companies languish in the double dunes of despair? There has been a lot of talk but not a lot of action. Listen to the team unpack recent developments and hopes for the future.

The podcast can be found on their website.

This paper investigates innovative solutions to enhance the performance and lifespan of standalone photovoltaic (PV)-based microgrids with a particular emphasis on off-grid communities. A major challenge in these systems is the limited lifespan of batteries. To overcome this issue researchers have created hybrid energy storage systems (HESS) along with advanced power management strategies. This study introduces innovative multi-level HESS approaches and a related energy management strategy designed to alleviate the charge/discharge stress on batteries. Comprehensive Matlab Simulink models of various HESS topologies within standalone PV microgrids are utilized to evaluate system performance under diverse weather conditions and load profiles for rural site. The findings reveal that the proposed HESS significantly extends battery life expectancy compared to existing solutions. Furthermore the paper presents a novel energy management strategy based on the Reduced Fractional Gradient Descent (RFGD) algorithm optimization tailored for hybrid systems that include photovoltaic fuel cell battery and supercapacitor components. This strategy aims to minimize hydrogen consumption of Fuel Cells (FCs) thereby supporting the production of green ammonia for local industrial use. The RFGD algorithm is selected for its minimal user-defined parameters and high convergence efficiency. The proposed method is compared with other algorithms such as the Lyrebird Optimization Algorithm (LOA) and Osprey Optimization Algorithm (OOA). The RFGD algorithm exhibits superior accuracy in optimizing energy management achieving a 15% reduction in hydrogen consumption. Its efficiency is evident from the reduced computational time compared to conventional algorithms. Although minor losses in computational resources were observed they were substantially lower than those associated with traditional optimization techniques. Overall the RFGD algorithm offers a robust and efficient solution for enhancing the performance of hybrid energy systems.

Tunisia's rapid industrial expansion and population growth have created a pressing energy deficit despite the country's significant yet largely untapped renewable energy potential. This study addressed this challenge by developing a comprehensive framework to identify and evaluate strategies for promoting green hydrogen production from renewable energy sources in Tunisia. A Strength Weakness Opportunity and Threat (SWOT) analysis incorporating social economic and environmental dimensions was conducted to formulate potential solutions. The Step-wise Weight Assessment Ratio Analysis (SWARA) method facilitated the weighting of SWOT factors and subfactors. Subsequently a multi-criteria decision-making approach employing the gray technique for order preference by similarity to ideal solution (TOPSIS-G) method (validated by gray additive ratio assessment (ARAS-G) gray complex proportional assessment (COPRAS-G) and gray multi-objective optimization by ratio analysis (MOORA-G) was used to rank the identified strategies. The SWOT analysis revealed "Strengths" as the most influential factor with a relative weight of 47.3% followed by "Weaknesses" (26.5%) "Threats" (15.6%) and "Opportunities" (10.6%). Specifically experts emphasized Tunisia's renewable energy potential (21.89%) and robust power system (12.11%) as primary strengths. Conversely high investment costs (11.2%) and political instability (7.77%) posed substantial threat. Positive socio-economic impacts represented a key opportunity with a score of 5.2%. As for the strategies prioritizing criteria production cost ranked first with a score of 13.5% followed by environmental impact (12.8%) renewable energy potential (12.0%) and mitigation costs (11.3%). The gray TOPSIS analysis identified two key strategies: leveraging Tunisia's wind and solar resources and fostering regional cooperation for project implementation. The robustness of these strategies is confirmed by the strong correlation between TOPSIS-G ARAS-G COPRAS-G and MOORA-G results. Overall the study provides a comprehensive roadmap and expert-informed decision-support tools offering valuable insights for policymakers investors and stakeholders in Tunisia and other emerging economies facing similar energy challenges.

Nowadays with the need for clean and sustainable energy at its historical peak new equipment strategies and methods have to be developed to reduce environmental pollution. Drastic steps and measures have already been taken on a global scale. Renewable energy sources (RESs) are being installed with a growing rhythm in the power grids. Such installations and operations in power systems must also be economically viable over time to attract more investors thus creating a cycle where green energy e.g. green hydrogen production will be both environmentally friendly and economically beneficial. This work presents a management method for assessing wind–solar– hydrogen (H2 ) energy systems. To optimize component sizing and calculate the cost of the produced H2 the basic procedure of the whole management method includes chronological simulations and economic calculations. The proposed system consists of a wind turbine (WT) a photovoltaic (PV) unit an electrolyzer a compressor a storage tank a fuel cell (FC) and various power converters. The paper presents a case study of green hydrogen production on Sifnos Island in Greece through RES together with a scenario where hydrogen vehicle consumption and RES production are higher during the summer months. Hydrogen stations represent H2 demand. The proposed system is connected to the main power grid of the island to cover the load demand if the RES cannot do this. This study also includes a cost analysis due to the high investment costs. The levelized cost of energy (LCOE) and the cost of the produced H2 are calculated and some future simulations correlated with the main costs of the components of the proposed system are pointed out. The MATLAB language is used for all simulations.

Green hydrogen represents a critical underpinning technology for achievingcarbon neutrality. Although researchers often fixate on its energy inputs atruly ‘green’ hydrogen production process would also be sustainable in termsof water and materials inputs. To address this holistic challenge we demon-strate a new green hydrogen production system which can utilize secondarywastewater as the input (preserving scarce fresh water supplies for drinkingand sanitation). The enabling feature of the proposed system is a self-grownbifunctional CoNi electrode which consists of ultrathin spontaneously depos-ited CoNi nanosheets on a three-dimensional nickel foam. As such a greensynthesis process was developed using an immersion procedure at room-temperature with zero net energy input. Testing revealed that the synthesizedCoNi electrodes can reach a current density of 10 mA cm2 at a small overpo-tential of 197 mV for the hydrogen evolution reaction and 315 mV for the oxy-gen evolution reaction in alkalified wastewater. The values are 16.5%and 6.5% smaller than that from precious catalysts (20 wt% Pt/C and RuO 2 respectively). Importantly this CoNi catalyst offers outstanding durability foroverall wastewater splitting. A prototype solar-energy-powered rooftop waste-water splitting system was constructed and can produce more than 100 Lhydrogen on a sunny day in Sydney Australia. Taken together these resultsindicate that it is promising to unlock holistically green routes for hydrogenproduction by wastewater uplifting with regards to water energy and mate-rials synthesis.

Technological change is often seen as part of the solution to problems of global sustainability. A wide-ranging literature on how path dependent—often fossil fuel-based—socio-technical configurations can be overcome by more sustainable configurations has emerged over the last two decades. One potential transition pathway to transform electricity heat and mobility systems as well as industrial production is the use of hydrogen. In recent years hydrogen has received increasing attention as part of decarbonisation strategies in many countries as well as by international organisations such as the International Energy Agency or the International Renewable Energy Agency. Also in Germany it has become a central component of climate change policy and is seen by some actors almost as a kind of panacea where the use of hydrogen is expected to decarbonise a wide range of sectors. Policy makers have the ambition for Germany to become a leader in hydrogen development and therefore help to contribute to what Grubler called ‘grand patterns of technological change’. The aim of this paper is to analyse whether relevant actors share expectations for transition pathways based on hydrogen which would foster wide diffusion. Our empirical analysis shows that there are multiple contested pathways both in terms of how hydrogen is produced as well as in which applications or sectors it is to be used. This causes uncertainty and slows down hydrogen developments in Germany. We contribute to an emerging literature on the politics of contested transition pathways and also critically engage with Grubler’s ‘grand patterns’ argument. Results support the idea that the concept of socio-technical pathways allows to expose tensions between competing values and interests. The German government is under considerable pressure regarding competing visions on hydrogen transition pathways. A targeted political prioritisation of hydrogen applications could mitigate tensions and support a shared vision.

Underground coal gasification (UCG) is an emerging clean energy technology with significant potential for enhanced hydrogen production especially when coupled with water injection. Previous lab-scale studies have explored this potential but the mechanisms driving water-assisted hydrogen enhancement in large-scale deep UCG settings remain unclear. This study addresses this gap using numerical simulations of a large-scale deep coal model designed for hydrogen-oriented UCG. We investigated single-point and multipoint water injection stra tegies to optimize hydrogen production. Additionally we developed a retractable water injection technique to ensure sustained hydrogen output and effective cavity control. Our results indicate that the water–gas shift re action is crucial for increasing hydrogen production. Multipoint injection has been proven to be more effective than single-point injection increasing hydrogen production by 11% with an equal amount of steam. The introduction of retractable injection allows for continuous and efficient hydrogen generation with daily hydrogen production rates of approximately five times that of a conventional injection scheme and an increase in cumulative hydrogen production of approximately 105% over the same time period. Importantly the mul tipoint injection method also helped limit vertical cavity growth mitigating the risk of aquifer contamination. These findings support the potential of UCG as a low-carbon energy source in the transition to a hydrogen economy

The growing demand for air travel in the commercial sector leads to an increase in global emissions whose mitigation entails transitioning from the current fossil-fuel based generation of aircrafts to a cleaner one within a short timeframe. The use of hydrogen and fuel cells has the potential to reach zero emissions in the aerospace sector provided that required innovation and research efforts are substantially accomplished. Development programs investments and new regulations are needed for this technology to be safe and economical. In this context it makes sense to develop a model-based preliminary design methodology for a hybrid regional aircraft assisted by a battery hybridized fuel cell powertrain. The technological assumptions underlying the study refer to both current and expected data for 2035. The major contribution of the proposed methodology is to provide a mathematical tool that considers the interactions between the choice of components in terms of installed power and energy management. This simultaneous study is done because of the availability of versatile control maps. The tool was then deployed to define current and future technological scenarios for fuel cell battery and hydrogen storage systems by quickly adapting control strategies to different sizing criteria and technical specifications. In this way it is possible to facilitate the estimation of the impact of different sizing criteria and technological features at the aircraft level on the onboard electrical system the management of in-flight power the propulsion methods the impact of the masses on consumption and operational characteristics in a typical flight mission. The proposed combination of advanced sizing and energy management strategies allowed meeting mass and volume constraints with state-of-the-art PEM fuel cell and Li-ion battery specifications. Such a solution corresponds to a high degree of hybridization between the fuel cell system and battery pack (i.e. 300 kW and 750 kWh) whereas projected 2035 specs were demonstrated to help reduce mass and volume by 23 % and 40 % respectively.

The transition from traditional aviation fuels to low-emission alternatives such as hydrogen is a crucial step towards a sustainable future for aviation. Conventional jet fuels substantially contribute to greenhouse gas emissions and climate change. Hydrogen fuel especially "green" hydrogen offers great potential for achieving full sustainability in aviation. Hybrid/electric/fuel cell technologies may be used for shorter flights while longrange aircraft are more likely to combust hydrogen in gas turbines. Liquid hydrogen is necessary to minimize storage tank weight but the required fuel systems are at a low technology readiness level and differ significantly from Jet A-1 systems in architecture operation and performance. This paper provides an in-depth review covering the development of liquid hydrogen fuel system design concepts for gas turbines since the 1950s compares insights from key projects such as NASA studies and ENABLEH2 alongside an analysis of recent publications and patent applications and identifies the technological advancements required for achieving zeroemission targets through hydrogen-fuelled propulsion.

This research analyzed the impact of green hydrogen (GH) on the dynamics of combating climate change (CC) in Peru for the year 2024 contributing to Sustainable Development Goal 7 focused on affordable and clean energy. The study quantitative and non-experimental in nature used a cross-sectional design and focused on a sample composed of public and private sector officials energy experts and academics evaluating their perception and knowledge about GH and its application in climate policies. The data collection instrument showed good internal consistency with a Cronbach’s alpha value of 0.793. The results revealed that although the adoption of GH is in its early stages it is already considered a vital component in national CC mitigation strategies. A medium positive correlation was identified using the Spearman coefficient (0.418) between GH usage and the effectiveness of mitigation policies as well as its capacity to influence public awareness and promote interinstitutional cooperation. Furthermore it was concluded that the success of GH largely depends on the strengthening of regulatory frameworks investment in infrastructure and the promotion of strategic alliances to facilitate its integration into the national energy matrix. These findings highlight the importance of continuing to develop public policies that promote the use of GH ensuring its sustainability and effectiveness in the fight against climate change in Peru.

This paper analyzes the hydrogen refueling process for heavy-duty vehicles according to the SAE J2601/2 protocol. Attention is paid to two key aspects of the protocol that affect the refueling process: treatment of the storage system from a thermodynamic and geometric point of view and the maximum deliverable flow rate of the station in the refueling process. The effect of the ratio of the inner diameter to the inner length of the total volume on the refueling process was then analyzed and it was shown how far the new approach results deviate from the results obtained by applying the SAE protocol. A total supply of 28 kg was simulated but with three different configurations: 14*2 kg tanks 7*4 kg tanks and 4*7 kg tanks. When analyzing the effect of varying the ratio of inner diameter to inner length it was noted that in the most conservative case there is an overestimation in terms of final temperature for the three configurations of about: 2.1 ◦C 1.4 ◦C and 1.1 ◦C respectively. This aspect has a significant impact on the refueling time which could be reduced by about 9.9% in the first case and about 7.1% and 5.4% in the other two. In addition refueling using the multi-tank approach was simulated for some case studies assimilated to heavy vehicles currently on the market in terms of the amount of hydrogen stored. These refuelings were carried out with stations capable of delivering a maximum flow rate of 120 g/s 180 g/s and 240 g/s. It is inferred that increasing the flow rate from 120 g/s to 180 g/s results in time savings for the three cases of: 35% 34% and 37%. On the other hand running up to 240 g/s results in time savings of: 54% 52% and 55%.

Despite the growing recognition of hydrogen’s potential role in sustainable development there is limited un derstanding of how national hydrogen strategies align with the United Nations Sustainable Development Goals (SDGs). This study addresses this knowledge gap by examining the integration of the SDGs into national hydrogen strategies through text analysis. Among 66 reviewed strategic documents only 15 explicitly reference specific SDGs though SDG-related keywords are widespread particularly regarding SDG 7 (Affordable and Clean Energy) and SDG 13 (Climate Action). Statistical analysis demonstrates a significant link between the presence of hydrogen strategies and both overall SDG performance and progress on most specific SDGs. However countries with hydrogen strategies show lower scores for SDGs 12 (Responsible Consumption and Production) and 13 and there are no significant differences for SDGs 10 (Reduced Inequalities) 14 (Life below Water) and 15 (Life on Land). Our findings highlight the need for more explicit integration of SDGs into hydrogen strategies and better consideration of sustainability synergies and trade-offs providing policymakers with evidence-based guidance for aligning hydrogen strategies with global sustainability objectives.

The decarbonization of sectors such as aviation maritime transport and heavy-duty mobility—where direct electrification is not yet feasible—requires alternative fuels with high energy density and compatibility with existing infrastructure. This review investigates the potential of liquid synthetic fuels known as liquid electrofuels (or e-fuels) to replace fossil fuels in these hard-to-abate sectors. The objective is to provide a comprehensive integrative assessment of liquid e-fuel development by analyzing production pathways feedstock demands regulatory frameworks and industrial implementation trends. The study reviews three major production processes—Fischer–Tropsch synthesis methanol synthesis and the Haber–Bosch process—used to produce six key synthetic fuels: e-kerosene e-diesel e-methanol e-dimethyl ether e-gasoline and e-ammonia. The methodology includes a systematic review of literature life cycle assessments for water and energy demand and analysis of over 30 large-scale projects worldwide in terms of plant capacity (10–200 MW) production volume capital investment and technology readiness level. Results show that process efficiencies range from 59 % to 89 % with current production costs for synthetic kerosene and methanol varying between 1200–4200 €/ton depending on the pathway and technology maturity. The study finds that polymer electrolyte membrane electrolysis and industrial point-source carbon dioxide capture are the most prevalent technologies among operational plants. Regulatory complexity high capital expenditure and the lack of harmonized sustainability criteria remain key barriers to commercial scaling. This review advances the scientific literature by presenting a novel multi-dimensional framework that connects technical environmental and policy considerations offering a strategic roadmap for accelerating the global deployment of liquid synthetic fuels.

: The global demand for energy and the need to mitigate climate change require a shift from traditional fossil fuels to sustainable and renewable energy alternatives. Hydrogen is recognized as a significant component for achieving a carbon-neutral economy. This comprehensive review examines the underground hydrogen storage and particularly laboratory-scale studies related to rock– hydrogen interaction exploring current knowledge. Using bibliometric analysis of data from the Scopus and Web of Science databases this study reveals an exponential increase in scientific publications post-2015 which accounts for approximately 85.26% of total research output in this field and the relevance of laboratory experiments to understand the physicochemical interactions of hydrogen with geological formations. Processes in underground hydrogen storage are controlled by a set of multi-scale parameters including solid properties (permeability porosity composition and geomechanical properties) and fluid properties (liquid and gas density viscosity etc.) together with fluid–fluid and solid–fluid interactions (controlled by solubility wettability chemical reactions etc.). Laboratory experiments aim to characterize these parameters and their evolution simulating real-world storage conditions to enhance the reliability and applicability of findings. The review emphasizes the need to expand research efforts globally to comprehensively address the currently existing issues and knowledge gaps.

Hydrogen recombination catalyst is useful tool for reducing hydrogen in closed area. The catalyst is known to be poisoned under wet condition in long time use. The study is focused on the behavior of pre-oxidized Pd nanoparticle as the hard-used catalyst in high humidity environment by comparison of alumina and titanium oxide supports using in situ X-ray absorption spectroscopy technique. The reduction of surface oxide layer of Pd/TiO2 was promoted by water during hydrogen recombination although the reduction reaction of Pd/Al2O3 was inhibited by water.

The transformation of fossil fuel-based power generation systems towards greenhouse gas-neutral ones based on renewable energy sources is one of the key challenges facing contemporary society. The temporal volatility that accompanies the integration of renewable energy (e.g. solar radiation and wind) must be compensated to ensure that at any given time a sufficient supply of electrical energy for the demands of different sectors is available. Green hydrogen which is produced using renewable energy sources via electrolysis can be used to chemically store electrical energy on a seasonal basis. Reconversion technologies are needed to generate electricity from stored hydrogen during periods of low renewable electricity generation. This study presents a detailed technoeconomic assessment of hydrogen gas turbines. These technologies are also superior to fuel cells due to their comparatively low investment costs especially when it comes to covering the residual loads. As of today hydrogen gas turbines are only available in laboratory or small-scale settings and have no market penetration or high technology readiness level. The primary focus of this study is to analyze the effects on gas turbine component costs when hydrogen is used instead of natural gas. Based on these findings an economic analysis addressing the current state of these turbine components is conducted. A literature review on the subsystems is performed considering statements from leading manufactures and researchers to derive the cost deviations and total cost per installed capacity (€/kWel). The results reveal that a hydrogen gas turbine power plant has an expected cost increase of 8.5% compared to a conventional gas turbine one. This leads to an average cost of 542.5 €/kWel for hydrogen gas turbines. For hydrogen combined cycle power plants the expected cost increase corresponds to the cost of the gas turbine system as the steam turbine subsystem remains unaffected by fuel switching. Additionally power plant retrofit potentials were calculated and the respective costs in the case of an upgrade were estimated. For Germany as a case study for an industrialized country the potential of a possible retrofit is between 2.7 and 11.4 GW resulting to a total investment between 0.3 and 1.1 billion €.

One of the most important problems in the widespread use of electric vehicles is the lack of charging infrastructure. Especially in tourist areas where historical buildings are located the installation of a power grid for the installation of electric vehicle charging stations or generating electrical energy by installing renewable energy production systems such as large-sized PV (photovoltaic) and wind turbines poses a problem because it causes the deterioration of the historical texture. Considering the need for renewable energy sources in the transportation sector our aim in this study is to model an electric vehicle charging station using PVPS (photovoltaic power system) and FC (fuel cell) power systems by using irradiation and temperature data from historical regions. This designed charging station model performs electric vehicle charging meeting the energy demand of a house and hydrogen production by feeding the electrolyzer with the surplus energy from producing electrical energy with the PVPS during the daytime. At night when there is no solar radiation electric vehicle charging and residential energy demand are met with an FC power system. One of the most important advantages of this system is the use of hydrogen storage instead of a battery system for energy storage and the conversion of hydrogen into electrical energy with an FC. Unlike other studies in our study fossil energy sources such as diesel generators are not included for the stable operation of the system. The system in this study may need hydrogen refueling in unfavorable climatic conditions and the energy storage capacity is limited by the hydrogen fuel tank capacity.

In response to the European Union’s initiative toward achieving carbon neutrality the utilization of water electrolysis for hydrogen production has emerged as a promising avenue for decarbonizing current energy systems. Among the various approaches Solid Oxide Electrolysis Cell (SOEC) presents an attractive solution especially due to its potential to utilize impure water sources. This study focuses on modeling a SOEC supplied with four distinct streams of treated municipal wastewaters using the Aspen Plus software. Through the simulation analysis it was determined that two of the wastewater streams could be effectively evaporated and treated within the cell without generating waste liquids containing excessive pollutant concentrations. Specifically by evaporating 27% of the first current and 10% of the second it was estimated that 26.2 kg/m3 and 9.7 kg/m3 of green hydrogen could be produced respectively. Considering the EU’s target for Italy is to have 5 GW of installed power capacity by 2030 and the mass flowrate of the analyzed wastewater streams this hydrogen production could meet anywhere from 0.4% to 20% of Italy’s projected electricity demand.

In the context of “dual carbon” restrictions on carbon emissions have aĴracted widespread aĴention from researchers. In order to solve the issue of the insufficient exploration of the synergistic emission reduction effects of various low-carbon policies and technologies applied to multiple microgrids we propose a multi-microgrid electricity cooperation optimization scheduling strategy based on stepped carbon trading a hydrogen-doped natural gas system and P2G–CCS coupled operation. Firstly a multi-energy microgrid model is developed coupled with hydrogendoped natural gas system and P2G–CCS and then carbon trading and a carbon emission restriction mechanism are introduced. Based on this a model for multi-microgrid electricity cooperation is established. Secondly design optimization strategies for solving the model are divided into the dayahead stage and the intraday stage. In the day-ahead stage an improved alternating direction multiplier method is used to distribute the model to minimize the cooperative costs of multiple microgrids. In the intraday stage based on the day-ahead scheduling results an intraday scheduling model is established and a rolling optimization strategy to adjust the output of microgrid equipment and energy purchases is adopted which reduces the impact of uncertainties in new energy output and load forecasting and improves the economic and low-carbon operation of multiple microgrids. SeĴing up different scenarios for experimental validation demonstrates the effectiveness of the introduced low-carbon policies and technologies as well as the effectiveness of their synergistic interaction

Hydrogen produced from renewable energy is being promoted to decarbonise global energy systems. To support this energy transition standards certification and labelling schemes (SCLs) aim to differentiate hydrogen products based on their system-wide carbon emissions and method of production characteristics. However being certified as low-carbon clean or green hydrogen does not guarantee broader sustainability across economic environmental social or governance dimensions. Through an international survey of energy-sector and sustainability professionals (n = 179) we investigated the desirable sustainability features for renewable hydrogen SCLs and the perceived advantages and disadvantages of sustainability certification. Our mixed-method study revealed general accordance on the feasible inclusion of diverse sustainability criteria in SCLs albeit with varying degrees of perceived essentiality. Within the confines of the data some differences in viewpoints emerged based on respondents’ geographical and supply chain locations which were associated with the sharing of costs and benefits. Qualitatively respondents found the idea of SCL harmonisation attractive but weighed this against the risks of duplication complicated administrative procedures and contradictory regulation. The implications of this research centre on the need for further studies to inform policy recommendations for an overarching SCL sustainability framework that embodies the principles of harmonisation in the context of multistakeholder governance.

Hydrogen storage is crucial to developing secure renewable energy systems to meet the European Union’s 2050 carbon neutrality objectives. However a knowledge gap exists concerning the site-specific performance and economic viability of utilizing underground gas storage (UGS) sites for hydrogen storage in Europe. We compile information on European UGS sites to assess potential hydrogen storage capacity and evaluate the associated current and future costs. The total hydrogen storage potential in Europe is 349 TWh of working gas energy (WGE) with site-specific capital costs ranging from $10 million to $1 billion. Porous media and salt caverns boasting a minimum storage capacity of 0.5 TWh WGE exhibit levelized costs of $1.5 and $0.8 per kilogram of hydrogen respectively. It is estimated that future levelized costs associated with hydrogen storage can potentially decrease to as low as $0.4 per kilogram after three experience cycles. Leveraging these techno-economic considerations we identify suitable storage sites.

In the framework of the “Multidisciplinary Optimization and Regulations for Low-boom and Environmentally Sustainable Supersonic aviation” project pursued by a consortium of European government and academic institutions coordinated by Politecnico di Torino under the European Commission Horizon 2020 financial support the Italian Aerospace Research Centre is computationally investigating the high-pressure hydrogen/air kinetic combustion in the operative conditions typically encountered in supersonic aeronautic ramjet engines. This task is being carried out starting from the zero-dimensional and one-dimensional chemical kinetic assessment of the complex and strongly pressure-sensitive ignition behavior and flame propagation characteristics of hydrogen combustion through the validation against experimental shock tube and laminar flame speed measurements. The 0D results indicate that the kinetic mechanism by Politecnico di Milano and the scheme formulated by Kéromnès et al. provide the best matching with the experimental ignition delay time measurements carried out in high-pressure shock tube strongly argon-diluted reaction conditions. Otherwise the best behavior in terms of laminar flame propagation is achieved by the Mueller scheme while the other investigated kinetic mechanisms fail to predict the flame speeds at elevated pressures. This confirms the non-linear and intensive pressure-sensitive behavior of hydrogen combustion especially in the critical high-pressure and low-temperature region which is hard to be described by a single all-encompassing chemical model.

The concept of underground gas storage is based on the natural capacity of geological formations such as aquifers depleted oil and gas reservoirs and salt caverns to store gases. Underground storage systems can be used to inject and store natural gas (NG) or hydrogen which can be withdrawn for transport to end-users or for use in industrial processes. Geological formations can additionally be used to securely contain harmful gases such as carbon dioxide deep underground by means of carbon capture and sequestration technologies. This paper defines and discusses underground gas storage highlighting commercial and pilot projects and the behavior of different gases (i.e. CH4 H2 and CO2) when stored underground as well as associated modeling investigations. For underground NG/H2 storage the maintenance of optimal subsurface conditions for efficient gas storage necessitates the use of a cushion gas. Cushion gas is injected before the injection of the working gas (NG/H2). The behavior of cushion gas varies based on the type of gas injected. Underground NG and H2 storage systems operate similarly. However compared to NG storage several challenges could be faced during H2 storage due to its low molecular mass. Underground NG storage is widely recognized and utilized as a reference for subsurface H2 storage systems. Furthermore this paper defines and briefly discusses carbon capture and sequestration underground. Most reported studies investigated the operating and cushion gas mixture. The mixture of operating and cushion gas was studied to explore how it could affect the recovered gas quality from the reservoir. The cushion gas was shown to influence the H2 capacity. By understanding and studying the different underground system technologies future directions for better management and successful operation of such systems are thereby highlighted.

The large deployment of hydrogen technologies for new applications such as heat power mobility and other emerging industrial utilizations is essential to meet targets for CO2 reduction. This will lead to an increase in the number of hydrogen installations nearby local populations that will handle hydrogen technologies. Local regulations differ and provide different safety and/or separation distances in different geographies. The purpose of this work is to give an insight on different methodologies and recommendations developed for hydrogen (mainly) risk management and consequences assessment of accidental scenarios. The first objective is to review available methodologies and to identify the divergent points on the methodology. For this purpose a survey has been launched to obtain the needed inputs from the subtask participants. The current work presents the outcomes of this survey highlighting the gaps and suggesting the prioritization of the actions to take to bridge these gaps.

In the quest for achieving decarbonisation it is essential for different sectors of the economy to collaborate and invest significantly. This study presents an innovative approach that merges technological insights with philosophical considerations at a national scale with the intention of shaping the national policy and practice. The aim of this research is to assist in formulating decarbonisation strategies for intricate economies. Libya a major oil exporter that can diversify its energy revenue sources is used as the case study. However the principles can be applied to develop decarbonisation strategies across the globe. The decarbonisation framework evaluated in this study encompasses wind-based renewable electricity hydrogen and gas turbine combined cycles. A comprehensive set of both official and unofficial national data was assembled integrated and analysed to conduct this study. The developed analytical model considers a variety of factors including consumption in different sectors geographical data weather patterns wind potential and consumption trends amongst others. When gaps and inconsistencies were encountered reasonable assumptions and projections were used to bridge them. This model is seen as a valuable foundation for developing replacement scenarios that can realistically guide production and user engagement towards decarbonisation. The aim of this model is to maintain the advantages of the current energy consumption level assuming a 2% growth rate and to assess changes in energy consumption in a fully green economy. While some level of speculation is present in the results important qualitative and quantitative insights emerge with the key takeaway being the use of hydrogen and the anticipated considerable increase in electricity demand. Two scenarios were evaluated: achieving energy self-sufficiency and replacing current oil exports with hydrogen exports on an energy content basis. This study offers for the first time a quantitative perspective on the wind-based infrastructure needs resulting from the evaluation of the two scenarios. In the first scenario energy requirements were based on replacing fossil fuels with renewable sources. In contrast the second scenario included maintaining energy exports at levels like the past substituting oil with hydrogen. The findings clearly demonstrate that this transition will demand great changes and substantial investments. The primary requirements identified are 20529 or 34199 km2 of land for wind turbine installations (for self-sufficiency and exports) and 44 single-shaft 600 MW combined-cycle hydrogen-fired gas turbines. This foundational analysis represents the commencement of the research investment and political agenda regarding the journey to achieving decarbonisation for a country.

The transportation industry’s transition to carbon neutrality is essential for addressing sustainability concerns. This study details a model for calculating the carbon footprint of the transportation sector as it progresses towards carbon neutrality. The model aims to support policymakers in estimating the potential impact of various decisions regarding transportation technology and infrastructure. It accounts for energy demand technological advancements and infrastructure upgrades as they relate to each transportation market: passenger vehicles commercial vehicles aircraft watercraft and trains. A technology roadmap underlies this model outlining anticipated advancements in batteries hydrogen storage biofuels renewable grid electricity and carbon capture and sequestration. By estimating the demand and the technologies that comprise each transportation market the model estimates carbon emissions. Results indicate that based on the technology roadmap carbon neutrality can be achieved by 2070 for the transportation sector. Furthermore the model found that carbon neutrality can still be achieved with slippage in the technology development schedule; however delays in infrastructure updates will delay carbon neutrality while resulting in a substantial increase in the cumulative carbon footprint of the transportation sector.

Green hydrogen (H2 ) a promising clean energy source garnering increasing attention worldwide can be derived through various pathways resulting in differing levels of greenhouse gas emissions. Notably Green H2 production can utilize different methods such as integrating standard photovoltaic panels thermal photovoltaic or concentrated photovoltaic thermal collectors with electrolyzers. Furthermore it can be conditioned to different states or carriers including liquefied H2 compressed H2 ammonia and methanol and stored and transported using various methods. This paper employs the Life Cycle Assessment methodology to compare 18 different green hydrogen pathways and provide recommendations for greening the hydrogen supply chain. The findings indicate that the production pathway utilizing concentrated photovoltaic thermal panels for electricity generation and hydrogen compression in the conditioning and transportation stages exhibits the lowest environmental impact emitting only 2.67 kg of CO2 per kg of H2 .

This review aims to enhance the understanding of the fundamentals applications and future directions in hydrogen production techniques. It highlights that the hydrogen economy depends on abundant non-dispatchable renewable energy from wind and solar to produce green hydrogen using excess electricity. The approach is not limited solely to existing methodologies but also explores the latest innovations in this dynamic field. It explores parameters that influence hydrogen production highlighting the importance of adequately controlling the temperature and concentration of the electrolytic medium to optimize the chemical reactions involved and ensure more efficient production. Additionally a synthesis of the means of transport and materials used for the efficient storage of hydrogen is conducted. These factors are essential for the practical feasibility and successful deployment of technologies utilizing this energy resource. Finally the technological innovations that are shaping the future of sustainable use of this energy resource are emphasized presenting a more efficient alternative compared to the fossil fuels currently used by society. In this context concrete examples that illustrate the application of hydrogen in emerging technologies are highlighted encompassing sectors such as transportation and the harnessing of renewable energy for green hydrogen production.

An important element of modern firefighting is sometimes the use of foam. After the use of extinguishing foam on vehicles or machinery operated by compressed gases it is conceivable that masses of foam were enriched by escaping fuel gas. Furthermore new foam creation enriched with a high level of fuel gas from the deposed foam solution becomes theoretically possible. The aim of this study was to carry out basic experimental investigations on the combustion of water-based H2/air foam. Ignition tests were carried out in a transparent and vertically oriented cylindrical tube (d = 0.09 m; 1.5 m length) and a rectangular thin layer channel (0.02 m x 0.2 m; 2 m length). Additionally results from larger scale tests performed inside a pool (0.30 m x 1 m x 2 m) are presented. All ducts are semi-confined and a foam generator fills the ducts from below with the defined foam. The foams vary in type and concentration of the foaming agent and hydrogen concentration. The expansion ratio of the combustible foam is in the range of 20 to 50 and the investigated H2-concentrations vary from 8 to 70 % H2 in air. High-speed imaging is used to observe the combustion and determine flame velocities. The study shows that foam is flammable over a wide range of H2-concentrations from 9 to 65 % H2 in air. For certain H2/air-mixtures an abrupt flame acceleration is observed. The velocity of combustion increases rapidly by an order of magnitude and reaches velocities of up to 80 m/s.

The shift from centralized to distributed generation and the need to address energy shortage and achieve the sustainability goals are among the important factors that drive increasing interests of governments planners and other relevant stakeholders in microgrid systems. Apart from the distributed renewable energy resources fuel cells (FCs) are a clean pollution-free highly efficient flexible and promising energy resource for microgrid applications that need more attention in research and development terms. Furthermore they can offer continuous operation and do not require recharging. This paper examines the exciting potential of FCs and their utilization in microgrid systems. It presents a comprehensive review of FCs with emphasis on the developmental status of the different technologies comparison of operational characteristics and the prevailing techno-economic barriers to their progress and the future outlook. Furthermore particular attention is paid to the applications of the FC technologies in microgrid systems such as grid-integrated grid-parallel stand-alone backup or emergency power and direct current systems including the FC control mechanisms and hybrid designs and the technical challenges faced when employing FCs in microgrids based on recent developments. Microgrids can help to strengthen the existing power grid and are also suitable for mitigating the problem of energy poverty in remote locations. The paper is expected to provide useful insights into advancing research and developments in clean energy generation through microgrid systems based on FCs.

Hydrogen fuel cell water-thermal management systems suffer from slow response time system vibration and large temperature fluctuations of load current changes. In this paper Logistic chaotic mapping adaptively adjusted inertia weight and asymmetric learning factors are integrated to enhance the particle swarm optimization (PSO) algorithm and combine it with fuzzy control to propose an innovative improved particle swarm optimization-Fuzzy control strategy. The use of chaotic mapping to initialize the particle population effectively enhances the variety within the population which subsequently improves the ability to search globally and prevents the algorithm from converging to a local optimum solution prematurely; by improving the parameters of learning coefficients and inertia weight the global and local search abilities are balanced at different stages of the algorithm so as to strengthen the algorithm’s convergence certainty while reducing the dependency on expert experience in fuzzy control. In this article a fuel cell experimental platform is constructed to confirm the validity and efficiency of the recommended strategy and the analysis reveals that the improved particle swarm optimization (IPSO) algorithm demonstrates better convergence performance than the standard PSO algorithm. The IPSO-Fuzzy-PID management approach is capable of providing a swift response and significantly diminishing the overshoot in the system’s performance to maintain the system’s safe and stable execution.

This study aims to carry out a techno-economic analysis of different hydrogen supply chain designs coupled with the Swedish electricity system to study the inter-dependencies between them. Both the hydrogen supply chain designs and the electricity system were parameterized with data for 2030. The supply chain designs comprehend centralised production decentralised production a combination of both and with/without seasonal variation in hydrogen demand. The supply chain design is modelled to minimize the overall cost while meeting the hydrogen demands. The outputs of the supply chain model include the hydrogen refuelling stations’ locations the electrolyser’s locations and their respective sizes as well as the operational schedule. The electricity system model shows that the average electricity prices in Sweden for zones SE1 SE2 SE3 and SE4 will be 4.28 1.88 8.21 and 8.19 €/MWh respectively. The electricity is mainly generated from wind and hydropower (around 42% each) followed by nuclear (14%) solar (2%) and then bio-energy (0.3%). In addition the hydrogen supply chain design that leads to a lower overall cost is the decentralised design with a cost of 1.48 and 1.68 €/kgH2 in scenarios without and with seasonal variation respectively. The seasonal variation in hydrogen demand increases the cost of hydrogen regardless of the supply chain design.

The utilisation of hydrogen in ships has important potential in terms of achieving the decarbonisation of waterway transport which produces approximately 3% of the world’s total emissions. However the utilisation of hydrogen drives in maritime and inland shipping is conditioned by the efficient and safe storage of hydrogen as an energy carrier on ship decks. Regardless of the type the constructional design and the purpose of the aforesaid vessels the preferred method for hydrogen storage on ships is currently high-pressure storage with an operating pressure of the fuel storage tanks amounting to tens of MPa. Alternative methods for hydrogen storage include storing the hydrogen in its liquid form or in hydrides as adsorbed hydrogen and reformed fuels. In the present article a method for hydrogen storage in metal hydrides is discussed particularly in a certified low-pressure metal hydride storage tank—the MNTZV-159. The article also analyses the 2D heat conduction in a transversal cross-section of the MNTZV-159 storage tank for the purpose of creating a final design of the shape of a heat exchanger (intensifier) that will help to shorten the total time of hydrogen absorption into the alloy i.e. the filling process. Based on the performed 3D calculations for heat conduction the optimisation and implementation of the intensifier into the internal volume of a metal hydride alloy will increase the performance efficiency of the shell heat exchanger of the MNTZV-159 storage tank. The optimised design increased the cooling power by 46.1% which shortened the refuelling time by 41% to 2351 s. During that time the cooling system which comprised the newly designed internal heat transfer intensifier was capable of eliminating the total heat from the surface of the storage tank thus preventing a pressure increase above the allowable value of 30 bar.