Publications

In the frame of the EC-funded project PRESLHY ten experiments on LH2-pool evaporation above four different substrates have been performed with the POOL-facility on a free field test site. Substrates to be investigated comprised concrete sand water and gravel. Four of the experiments were made with artificial side wind of known direction and known velocity to investigate the influence of side wind on hydrogen evaporation and cloud formation above the LH2-pool. The POOL-facility mainly consists of an insulated stainless-steel box with the dimensions 0.5 x 0.5 x 0.2 m³ that is filled up to half the height (0.1 m) with the respective substrate and LH2. The height of the LH2-pool that forms above the substrate can be determined using the weight of the complete facility which is positioned on a scale. Additionally six thermocouples are located in different heights above the substrate surface to indicate the LH2-level as soon as they are covered with LH2. Further measurement equipment used in the tests comprises temperature measurements inside the substrate and several thermocouples in the unconfined space above the pool where also H2-concentration measurements were performed. Using the sensor information pool evaporation rates for the different substrates were determined. The temperature and concentration measurements above the pool were mainly used to define promising ignition positions for subsequent combustion experiments in which the LH2-spills above the different substrates were ignited.

A novel multi-objective robust optimization model of an integrated energy system with hydrogen storage (HIES) considering source–load uncertainty is proposed to promote the low-carbon economy operation of the integrated energy system of a park. Firstly the lowest total system cost and carbon emissions are selected as the multi-objective optimization functions. The Pareto front solution set of the objective function is applied by compromise planning and the optimal solution among them is obtained by the maximum–minimum fuzzy method. Furthermore the robust optimization (RO) approach is introduced to cope with the source–load uncertainty effectively. Finally it is demonstrated that the illustrated HIES can significantly reduce the total system cost carbon emissions and abandoned wind and solar power. Meanwhile the effectiveness of the proposed model and solution method is verified by analyzing the influence of multi-objective solutions and a robust coefficient on the Chongli Demonstration Project in Hebei Province.

The addition of small amounts of certain gases such as O2 CO and SO2 may mitigate hydrogen embrittlement in high-pressure gas transmission pipelines that transport hydrogen. To practically implement such inhibition in gas transmission pipelines a comprehensive understanding and quantification of this effect are essential. This review examines the impact of various added gases to hydrogen including typical odorants on gaseous hydrogen embrittlement of steels and evaluates their inhibition effectiveness. O2 CO and SO2 were found to be effective inhibitors of hydrogen embrittlement. Yet the results in the literature have not always been consistent partly because of the diverse range of mechanical tests and their parameters. The absence of systematic studies hinders the evaluation of the feasibility of using gas phase inhibitors for controlling gaseous hydrogen embrittlement. A method to quantify the effectiveness of gas phase inhibition is proposed using gas phase permeation studies.

With the predicted high demand of hydrogen projected to support the neutral carbon society transition in the coming years the production of hydrogen is set to increase alongside the demand. As electrolysis is set to be amongst the main solutions for green hydrogen production ensuring the safety of electrolysers during operation will become a central concern. This is mainly due to the crossover risk (hydrogen into oxygen or the other way around) in the separators as throughout the years several cases of incidents have been reported. This study aims to evaluate the methodologies for calculating H2/O2 detonation cell size and laminar flame velocity using detailed kinetic mechanisms at the operating conditions of electrolysers (up to 35 bar and 360 K). Therefore the modeling of H2/O2 and H2/Air shock tube delay times and laminar flame speeds at initial different pressures and temperature based on the GRI mech 3.0 [1] Mevel et al.[2] Li et al.[3] Lutz et al. [4] and Burke et al. [5] kinetic mechanisms were performed and compared with the available experimental data in the literature. In each case a best candidate mechanism was then chosen to build a database for the detonation cell size then for the laminar flame speeds up to the operating conditions of electrolysers (293-360K and 1-35 bar).

The paper shows the latest developments of Gexcon’s consequence modelling software EFFECTS with validation based on hydrogen experimental data for different storage conditions and scenarios including liquid hydrogen two-phase jet releases. The effect of atmospheric turbulence on the dispersion and potential worst-case scenarios of hydrogen which are very different from heavy gas releases are discussed. Beside validation for gaseous hydrogen releases a validation study for pressurised liquid hydrogen jet releases including a sensitivity analysis is performed and the results are compared with experimental data.

The global resurgence of hydrogen as a clean energy source particularly green hydrogen derived from renewable energy is pivotal for achieving a carbon-neutral future. However scalability poses a significant challenge. This research proposes innovative business models leveraging the low-emission property of green hydrogen to reduce its financial costs thereby fostering its widespread adoption. Key components of the business workflow are elaborated mathematical formulations of market parameters are derived and case studies are presented to demonstrate the feasibility and efficiency of these models. Results demonstrate that the substantial costs associated with the current hydrogen industry can be effectively subsidized via the implementation of proposed business models. When the carbon emission price falls within the range of approximately 86–105 USD/ton free access to hydrogen becomes a viable option for end-users. This highlights the significance and promising potential of the proposed business models within the green hydrogen credit framework.

Many factors to be appropriately addressed in moving towards energy sustainability are examined. These include harnessing sustainable energy sources utilizing sustainable energy carriers increasing efficiency reducing environmental impact and improving socioeconomic acceptability. The latter factor includes community involvement and social acceptability economic affordability and equity lifestyles land use and aesthetics. Numerous illustrations demonstrate measures consistent with the approach put forward and options for energy sustainability and the broader objective of sustainability. Energy sustainability is of great importance to overall sustainability given the pervasiveness of energy use its importance in economic development and living standards and its impact on the environment.

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.

Renewable hydrogen is a flexible and versatile energy vector that can facilitate the decarbonization of several sectors and simultaneously ease the stress on the electricity grids that are currently being saturated with intermittent renewable power. But hydrogen technologies are currently facing limitations related to existing infrastructure limitations available markets as well as production storage and distribution costs. These challenges will be gradually addressed through the establishment operation and scaling-up of hydrogen valleys. Hydrogen valleys are an important stepping stone towards the full-scale implementation of the hydrogen economy with the target to foster sustainability lower carbon emissions and derisk the associated hydrogen technologies. These hydrogen ecosystems integrate renewable energy sources efficient hydrogen production storage transportation technologies as well as diverse end-users within a defined geographical region. This study offers an overview of the hydrogen valleys concept analyzing the critical aspects of their design and the key segments that constitute the framework of a hydrogen valley. А holistic overview of the key characteristics of a hydrogen valley is provided whereas an overview of key on-going hydrogen valley projects is presented. This work underscores the importance of addressing challenges related to the integration of renewable energy sources into electricity grids as well as scale-up challenges associated with economic and market conditions society awareness and political decision-making.

With the rapid development of hydrogen energy worldwide the number of hydrogen energy facilities such as hydrogen refueling stations has grown rapidly in recent years. However hydrogen is prone to leakage accidents during use which could lead to hazards such as fires and explosions. Therefore research on the safety of hydrogen energy facilities is crucial. In this paper a study of high-pressure hydrogen jet flame accidents is conducted for a proposed integrated hydrogen production and refueling station in China. The effects of leakage direction and leakage port diameter on the jet flame characteristics are analyzed and a risk assessment of the flame accident is conducted. The results showed that the death range perpendicular to the flame direction increased from 2.23 m to 5.5 m when the diameter of the leakage port increased from 4 mm to 10 mm. When the diameter of the leakage port is larger than 8 mm the equipment on the scene will be within the boundaries of the damage. The consequences of fire can be effectively mitigated by a reasonable firewall setup to ensure the overall safety of the integrated station.

Water electrolysis using a proton exchange membrane (PEM) holds substantial promise to produce green hydrogen with zero carbon discharge. Although various techniques are available to produce hydrogen gas the water electrolysis process tends to be more cost-effective with greater advantages for energy storage devices. However one of the challenges associated with PEM water electrolysis is the accumulation of gas bubbles which can impair cell performance and result in lower hydrogen output. Achieving an in-depth knowledge of bubble dynamics during electrolysis is essential for optimal cell performance. This review paper discusses bubble behaviors measuring techniques and other aspects of bubble dynamics in PEM water electrolysis. It also examines bubble behavior under different operating conditions as well as the system geometry. The current review paper will further improve the understanding of bubble dynamics in PEM water electrolysis facilitating more competent inexpensive and feasible green hydrogen production.

The global energy landscape is experiencing a transformative shift with an increasing emphasis on sustainable and clean energy sources. Hydrogen remains a promising candidate for decarbonization energy storage and as an alternative fuel. This study explores the landscape of hydrogen pricing and demand dynamics by evaluating three collaboration scenarios: market-based pricing cooperative integration and coordinated decision-making. It incorporates price-sensitive demand environmentally friendly production methods and market penetration effects to provide insights into maximizing market share profitability and sustainability within the hydrogen industry. This study contributes to understanding the complexities of collaboration by analyzing those structures and their role in a fast transition to clean hydrogen production by balancing economic viability and environmental goals. The findings reveal that the cooperative integration strategy is the most effective for sustainable growth increasing green hydrogen’s market share to 19.06 % and highlighting the potential for environmentally conscious hydrogen production. They also suggest that the coordinated decision-making approach enhances profitability through collaborative tariff contracts while balancing economic viability and environmental goals. This study also underscores the importance of strategic pricing mechanisms policy alignment and the role of hydrogen hubs in achieving sustainable growth in the hydrogen sector. By highlighting the uncertainties and potential barriers this research offers actionable guidance for policymakers and industry players in shaping a competitive and sustainable energy marketplace.

This paper aims to perform a systematic review with a bibliometric approach of the technoeconomic evaluation studies of hydrogen production. To achieve this objective a comprehensive outline of hydrogen production processes from fossil and renewable sources is presented. The results reveal that electrolysis classified as water splitting is the most investigated process in the literature since it contributes to a reduction in greenhouse gas emissions and presents other advantages such as maturity and applicability energy efficiency flexibility and energy storage potential. In addition the processes of gasification classified as thermochemical and steam reforming classified as catalytic reforming are worth mentioning. Regarding the biological category there is a balance between research on photo fermentation and dark fermentation. The literature on the techno-economic evaluation of hydrogen production highlights significant gaps including a scarcity of comprehensive studies a lack of emphasis on commercial viability an absence of sensitivity analysis and the need for comparative analyses between production technologies.

To further optimize the low-carbon economy of the integrated energy system (IES) this paper establishes a two-stage P2G hydrogen-coupled electricity–heat–hydrogen–gas IES with carbon capture (CCS). First this paper refines the two stages of P2G and introduces a hydrogen fuel cell (HFC) with a hydrogen storage device to fully utilize the hydrogen energy in the first stage of power-to-gas (P2G). Then the ladder carbon trading mechanism is considered and CCS is introduced to further reduce the system’s carbon emissions while coupling with P2G. Finally the adjustable thermoelectric ratio characteristics of the combined heat and power unit (CHP) and HFC are considered to improve the energy utilization efficiency of the system and to reduce the system operating costs. This paper set up arithmetic examples to analyze from several perspectives and the results show that the introduction of CCS can reduce carbon emissions by 41.83%. In the CCS-containing case refining the P2G two-stage and coupling it with HFC and hydrogen storage can lead to a 30% reduction in carbon emissions and a 61% reduction in wind abandonment costs; consideration of CHP and HFC adjustable thermoelectric ratios can result in a 16% reduction in purchased energy costs.

This study proposes four kinds of hybrid source–grid–storage systems consisting of pho‐ tovoltaic and wind energy and a power grid including different batteries and hydrogen storage systems for Sanjiao town. HOMER‐PRO was applied for the optimal design and techno‐economic analysis of each case aiming to explore reproducible energy supply solutions for China’s industrial clusters. The results show that the proposed system is a fully feasible and reliable solution for in‐ dustry‐based towns like Sanjiao in their pursuit of carbon neutrality. In addition the source‐side price sensitivity analysis found that the hydrogen storage solution was cost‐competitive only when the capital costs on the storage and source sides were reduced by about 70%. However the hydro‐ gen storage system had the lowest carbon emissions about 14% lower than the battery ones. It was also found that power generation cost reduction had a more prominent effect on the whole system’s NPC and LCOE reduction. This suggests that policy support needs to continue to push for genera‐ tion‐side innovation and scaling up while research on different energy storage types should be en‐ couraged to serve the needs of different source–grid–load–storage systems.

This research investigates the potential of using bedded salt formations for underground hydrogen storage. We present a novel artificial intelligence framework that employs spatial data analysis and multi-criteria decision-making to pinpoint the most appropriate sites for hydrogen storage in salt caverns. This methodology incorporates a comprehensive platform enhanced by a deep learning algorithm specifically a convolutional neural network (CNN) to generate suitability maps for rock salt deposits for hydrogen storage. The efficacy of the CNN algorithm was assessed using metrics such as Mean Absolute Error (MAE) Mean Squared Error (MSE) Root Mean Square Error (RMSE) and the Correlation Coefficient (R2 ) with comparisons made to a real-world dataset. The CNN model showed outstanding performance with an R2 of 0.96 MSE of 1.97 MAE of 1.003 and RMSE of 1.4. This novel approach leverages advanced deep learning techniques to offer a unique framework for assessing the viability of underground hydrogen storage. It presents a significant advancement in the field offering valuable insights for a wide range of stakeholders and facilitating the identification of ideal sites for hydrogen storage facilities thereby supporting informed decisionmaking and sustainable energy infrastructure development.

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

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.

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.

Hydrogen-fuelled technologies for home heating and cooking may provide a low-carbon solution for decarbonising parts of the global housing stock. For the transition to transpire the attitudes and perceptions of consumers must be factored into policy making efforts. However empirical studies are yet to explore potential levels of consumer heterogeneity regarding domestic hydrogen acceptance. In response this study explores a wide spectrum of consumer responses towards the prospect of hydrogen homes. The proposed spectrum is conceptualised in terms of the ‘domestic hydrogen acceptance matrix’ which is examined through a nationally representative online survey conducted in the United Kingdom. The results draw attention to the importance of interest and engagement in environmental issues knowledge and awareness of renewable energy technologies and early adoption potential as key drivers of domestic hydrogen acceptance. Critically strategic measures should be taken to convert hydrogen scepticism and pessimism into hope and optimism by recognising the multidimensional nature of consumer acceptance. To this end resources should be dedicated towards increasing the observability and trialability of hydrogen homes in proximity to industrial clusters and hubs where the stakes for consumer acceptance are highest. Progress towards realising a net-zero society can be supported by early stakeholder engagement with the domestic hydrogen acceptance matrix.

The necessity for transitioning to renewable energy sources and the intermittent nature of the natural variables lead to the integration of storage units into these projects. In this research paper wind turbines and solar modules are combined with pumped hydro storage batteries and green hydrogen. Energy management strategies are described for five different scenarios of hybrid renewable energy systems based on single or hybrid storage technologies. The motivation is driven by grid stability issues and the limited access to fresh water in the Greek islands. A RES-based desalination unit is introduced into the hybrid system for access to low-cost fresh water. The comparison of single and hybrid storage methods the exploitation of seawater for the simultaneous fulfillment of water for domestic and agricultural purposes and the evaluation of different energy economic and environmental indices are the innovative aspects of this research work. The results show that pumped hydro storage systems can cover the energy and water demand at the minimum possible price 0.215 EUR/kWh and 1.257 EUR/m3 while hybrid storage technologies provide better results in the loss of load probability payback period and CO2 emissions. For the pumped hydro– hydrogen hybrid storage system these values are 21.40% 10.87 years and 2297 tn/year respectively.

As countries work towards achieving net-zero emissions the need for cleaner fuels has become increasingly urgent. Hydrogen produced from fossil fuels with carbon capture and storage (blue hydrogen) has the potential to play a significant role in the transition to a low-carbon economy. This study examined the technical and economic potential of blue hydrogen produced at 600 MWth(LHV) and scaled up to 1000 MWth(LHV) by benchmarking sorption-enhanced steam reforming process against steam methane reforming (SMR) autothermal gasheated reforming (ATR-GHR) integrated with carbon capture and storage (CCS) and SMR with CCS. Aspen Plus® was used to develop the process model which was validated using literature data. Cost sensitivity analyses were also performed on two key indicators: levelised cost of hydrogen and CO2 avoidance cost by varying natural gas price electricity price CO2 transport and storage cost and carbon price. Results indicate that at a carbon price of 83 £/tCO2e the LCOH for SE-SR of methane is the lowest at 2.85 £/kgH2 which is 12.58% and 22.55% lower than that of ATR-GHR with CCS and SMR plant with CCS respectively. The LCOH of ATR-GHR with CCS and SMR plant with CCS was estimated to be 3.26 and 3.68 £/kgH2 respectively. The CO2 avoidance cost was also observed to be lowest for SE-SR followed by ATR-GHR with CCS then SMR plant with CCS and was observed to reduce as the plant scaled to 1000 MWth(LHV) for these technologies.

The depletion and overuse of fossil fuels present formidable challenge to energy supply system and environment. The human society is in great need of clean renewable and sustainable energy which can guarantee the long-term utilization without leading to escalation of greenhouse effect. Hydrogen as an extraordinary secondary energy is capable of realizing the target of environmental protection and transferring the intermittent primary energy to the application terminal while its nature of low volumetric energy density and volatility need suitable storage method and proper carrier. In this context liquid organic hydrogen carrier (LOHC) among a series of storage methods such as compressed and liquefied hydrogen provokes a considerable amount of research interest since it is proven to be a suitable carrier for hydrogen with safety and stability. However the dehydrogenation of hydrogen-rich LOHC materials is an endothermic process and needs large energy consumption which hampers the scale up of the LOHC system. The heat issue is thus essential to be addressed for fulfilling the potential of LOHC. In this work several strategies of heat intensification and management for LOHC system including the microwave irradiation circulation of exhaust heat and direct LOHC fuel cell are summarized and analyzed to provide suggestions and directions for future research.

Energy decarbonisation is essential to achieve Net-Zero emissions goal by 2050. Consequently investments in alternative low-carbon pathways and energy carriers for the heat sector are required. In this study we propose an optimisation framework for the transition of heat sector in Great Britain focusing on hydrogen infrastructure decisions. A spatially-explicit mixed-integer linear programming (MILP) evolution model is developed to minimise the total system’s cost considering investment and operational decisions. The optimisation framework incorporates both long-term planning horizon of 5-year steps from 2035 to 2050 and typical days with hourly resolution. Aiming to alleviate the computational effort of such multiscale model two hierarchical solution approaches are suggested that result in computational time reduction. From the optimisation results it is shown that the installation of gas reforming hydrogen production technologies with CCS and biomass gasification with CCS can provide a cost-effective strategy achieving decarbonisation goal. What-if analysis is conducted to demonstrate further insights for future hydrogen infrastructure investments. Results indicate that as cost is highly dependent on natural gas price Water Electrolysis capacity increases significantly when gas price rises. Moreover the introduction of carbon tax policy can lead to lower CO2 net emissions.

The application of hydrogen energy produced by proton exchange membrane electrolyzer (PEMEC) is conducive to the solution of the greenhouse effect and the energy crisis. In order to understand the development trends and research hotspot of PEMEC in recent years a total of 1874 research articles related to this field from 2003 to 2023 were obtained from the Web of Science Core Collection (WoS CC) database. The visualization software VOSviewer is used for bibliometric analysis and the research progress hotspots and trends in the PEMEC field are summarized. It was found that in the past two decades literature in the PEMEC field has shown a trend of stable increase at first and then rapidly increasing. And it is in a stage of rapid growth after 2021.Renewable Energy previously published research articles related to PEMEC with the highest frequency of citations. There are a total of 6128 researchers in this field but core authors only account for 4.5% of the total. Although China entered this field later than the United States and Canada it has the largest number of research articles. The research results provide a comprehensive overview of various aspects in the PEMEC field which is beneficial for researchers to grasp the development hotspots of PEMEC.

Concerns related to climate change have shifted global attention towards advanced sustainable and decarbonized energy systems. While renewable resources such as wind and solar energy offer environmentally friendly alternatives their inherent variability and intermittency present significant challenges to grid stability and reliability. The integration of renewable energy sources requires innovative solutions to effectively balance supply and demand in the electricity grid. This review explores the critical role of electrolyzer systems in addressing these challenges by providing ancillary services to modern electricity grids. Electrolyzers traditionally used only for hydrogen production have now emerged as versatile tools capable of responding quickly to grid load variations. They can consume electricity during excess periods or when integrated with fuel cells generate electricity during peak demand contributing to grid stability. Therefore electrolyzer systems can fulfill the dual function of producing hydrogen for the end-user and offering grid balancing services ensuring greater economic feasibility. This review paper aims to provide a comprehensive view of the electrolyzer systems’ role in the provision of ancillary services including frequency control voltage control congestion management and black start. The technical aspects market projects challenges and future prospects of using electrolyzers to provide ancillary services in modern energy systems are explored.

Building a hydrogen economy is perceived as a way to achieve the decarbonization goals set out in the Paris Agreement to limit global warming as well as to meet the goals resulting from the European Green Deal for the decarbonization of Europe. This article presents a literature review of various aspects of this economy. The full added value chain of hydrogen was analyzed from its production through to storage transport distribution and use in various economic sectors. The current state of knowledge about hydrogen is presented with particular emphasis on its features that may determine the positives and negatives of its development. It was noted that although hydrogen has been known for many years its production methods are mainly related to fossil fuels which result in greenhouse gas emissions. The area of interest of modern science is limited to green hydrogen produced as a result of electrolysis from electricity produced from renewable energy sources. The development of a clean hydrogen economy is limited by many factors the most important of which are the excessive costs of producing clean hydrogen. Research and development on all elements of the hydrogen production and use chain is necessary to contribute to increasing the scale of production and use of this raw material and thus reducing costs as a result of the efficiencies of scale and experience gained. The development of the hydrogen economy will be related to the development of the hydrogen trade and the centers of this trade will differ significantly from the current centers of energy carrier trade.

Hydrogen is the gas of the moment: an abundant element that can be created using renewable energy transported in gaseous or liquid form and offering the ability to provide energy with only water vapour as an emission. Hydrogen can also be used in a fuel blend in electricity generation gas turbines providing a low carbon option for providing the peak electricity to cover high demand and firming.<br/>While the electricity grid is itself transforming to decarbonising hard-to-abate industries such as cement and bauxite refineries are slower to reduce emissions constrained by their high temperature process requirements. Hydrogen offers a solution allowing onsite production process heat with waste heat recovery supporting blended gas turbine generation for onsite electricity supply.<br/>This article builds on decarbonisation pathway simulation results from an ANEM model of the electricity grid identifying the amount of peak demand energy required from gas turbines. The research then examines the quantity flow rate storage requirements and emissions reduction if this peak generation were supplied by open cycle hydrogen capable gas turbines.

Ever more stringent emission regulations for vehicles encourage increasing numbers of battery electric vehicles on the roads. A drawback of storing electric energy in a battery is the comparable low energy density low driving range and the higher propensity to deplete the energy storage before reaching the destination especially at low ambient temperatures. When the battery is depleted stranded vehicles can either be towed or recharged with a mobile recharging station. Several technologies of mobile recharging stations already exist however most of them use fossil fuels to recharge battery electric vehicles. The proposed novel zero emission solution for mobile charging is a combined high voltage battery and hydrogen fuel cell charging station. Due to the thermal characteristics of the fuel cell and high voltage battery (which allow only comparable low coolant temperatures) the thermal design for this specific application (available heat exchanger area zero vehicle speed air flow direction) becomes challenging and is addressed in this work. Experimental methods were used to obtain reliable thermal and electric power measurement data of a 30 kW fuel cell system which is used in the Mobile Hydrogen Powersupply. Subsequently simulation methods were applied for the thermal design and optimisation of the coolant circuits and heat exchangers. It is shown that an battery electric vehicle charging power of 22 kW requires a heat exchanger area of 1 m2 of which 60 % is used by the fuel cell heat exchanger and the remainder by the battery heat exchanger to achieve steady state operation at the highest possible ambient temperature of 436 °C. Furthermore the simulation showed that when the charging power of 22 kW is solely provided by the high voltage battery the highest possible ambient temperature is 42 °C. When the charging power is decreased operation up to the maximum ambient temperatures of 45 °C can be achieved. The results of maximum charging power and limiting ambient temperature give insights for further system improvements which are: sizing of fuel cell or battery trailer design and heat exchanger area operation strategy of the system (power split between high voltage battery and fuel cell) as well as possible dynamic operation scenarios.

Japan has formulated a net-zero emissions target by 2050. Existing scenarios consistent with this target generally depend on carbon dioxide removal (CDR). In addition to domestic mitigation actions the import of low-carbon energy carriers such as hydrogen and synfuels and negative emissions credits are alternative options for achieving net-zero emissions in Japan. Although the potential and costs of these actions depend on global energy system transition characteristics which can potentially be informed by the global integrated assessment models they are not considered in current national scenario assessments. This study explores diverse options for achieving Japan's net-zero emissions target by 2050 using a national energy system model informed by international energy trade and emission credits costs estimated with a global energy system model. We found that demand-side electrification and approximately 100 Mt-CO2 per year of CDR implementation equivalent to approximately 10% of the current national CO2 emissions are essential across all net-zero emissions scenarios. Upscaling of domestically generated hydrogen-based alternative fuels and energy demand reduction can avoid further reliance on CDR. While imports of hydrogen-based energy carriers and emission credits are effective options annual import costs exceed the current cost of fossil fuel imports. In addition import dependency reaches approximately 50% in the scenario relying on hydrogen imports. This study highlights the importance of considering global trade when developing national net-zero emissions scenarios and describes potential new roles for global models.

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.

Modernizing public transportation is crucial given the ongoing call for sustainable mobility. Growing concerns about climate change and the increasingly stringent emissions standards have compelled public transport operators to embrace alternative propulsion vehicles on a broader scale. For the past years the Battery Electric Buses (BEBs) have been the vehicle of choice for public transportation. However an emerging contender in this sector is the Fuel Cell Electric Bus (FCEB). This paper aims to evaluate the way one such vehicle would perform in terms of energy efficiency while being exploited in an urban scenario generated from collected data.

In a first-of-its-kind project for Alberta ATCO Gas and Pipelines Ltd. (ATCO) began delivering a 5% blend of hydrogen (H2) in natural gas into a subsection of the existing Fort Saskatchewan natural gas distribution system (approximately 2100 customers). The project was commissioned in October 2022 with the intention of increasing the blend to 20% H₂ in 2023. As part of project due diligence ATCO in partnership with DNV undertook Quantitative Risk Assessments (QRAs) to understand any risks associated with the introduction of blended gas into its existing distribution system and to its customers. This paper describes key findings from the QRAs through the comparison of risks associated with H2 blended natural gas at concentrations of 5% and 20% H₂ and the current natural gas configuration. The impact of operating pressure and hydrogen blend composition formed a sensitivity study completed as part of this work. To provide context and to help interpret the results an individual risk (IR) level of 1 × 10-6 per year was utilised as a reference threshold for the limit of the ‘broadly acceptable’ risk level and juxtaposed against comparable risk scenarios. Although adding hydrogen increases the IR of ignited releases from mains services meters regulators and end user appliances the ignited release IR was always well below the broadly acceptable reference criterion for all operating pressures and blend cases considered as part of the project. The IR associated with carbon monoxide poisoning dominates the overall IR and the results demonstrate that the reduction in carbon monoxide poisoning associated with the introduction of H₂ blended natural gas negates any incremental risk associated with ignited releases due to H₂ blended gas. The paper also explains how the results of the QRA were incorporated into Engineering Assessments as per the requirements of CSA Z662:19 [1] to justify the conversion of existing natural gas infrastructure to H₂ blended gas infrastructure.

The complexity of Fuel Cell (FC) systems demands a profound and sustained understanding of the various phenomena occurring inside of it. Thus far FCs especially Proton Exchange Membrane Fuel Cells (PEMFCs) have been recognized as being among the most promising technologies for reducing Green House Gas (GHG) emissions because they can convert the chemical energy bonded to hydrogen and oxygen into electricity and heat. However their efficiency remains limited. To enhance their efficiency two distinct factors are suggested. First the quality of materials plays a significant role in the development of more robust and efficient FCs. Second the ability to identify mitigate and reduce the occurrence of faults through the use of robust control algorithms is crucial. Therefore more focused on the second point this paper compiles distinguishes and analyzes several publications from the past 25 years related to faults and their diagnostic techniques in FCs. Furthermore the paper presents various schemes outlining different symptoms their causes and corresponding fault algorithms.

Natural gas is the most growing fossil fuel due to its environmental advantages. For the economical transportation of natural gas to distant markets physical (i.e. liquefaction and compression) or chemical (i.e. direct and indirect) monetisation options must be considered to reduce volume and meet the demand of different markets. Planning natural gas supply chains is a complex problem in today’s turbulent markets especially considering the uncertainties associated with final market demand and competition with emerging renewable and hydrogen energies. This review study evaluates the latest research on mathematical programming (i.e. MILP and MINLP) as a decisionmaking tool for designing and planning natural gas supply chains under different planning horizons. The first part of this study assesses the status of existing natural gas infrastructures by addressing readily available natural monetisation options quantitative tools for selecting monetisation options and single-state and multistate natural gas supply chain optimisation models. The second part investigates hydrogen as a potential energy carrier for integration with natural gas supply chains carbon capture utilisation and storage technologies. This integration is foreseen to decarbonise systems diversify the product portfolio and fill the gap between current supply chains and the future market need of cleaner energy commodities. Since natural gas markets are turbulent and hydrogen energy has the potential to replace fossil fuels in the future addressing stochastic conditions and demand uncertainty is vital to hedge against risks through designing a responsive supply chain in the project’s early design stages. Hence hydrogen supply chain optimisation studies and the latest works on hydrogen–natural gas supply chain optimisation were reviewed under deterministic and stochastic conditions. Only quantitative mathematical models for supply chain optimisation including linear and nonlinear programming models were considered in this study to evaluate the effectiveness of each proposed approach.

Thanks to investments in diversifying the supply of natural gas Poland did not encounter any gas supply issues in 2022 when gas imports from Russia were ceased due to the Russian Federation’s armed intervention in Ukraine. Over the past few years the supply of gas from routes other than the eastern route has substantially grown particularly the supplies of liquefied natural gas (LNG) via the LNG terminal in Swinouj´scie. The growing proportion of LNG in Poland’s gas supply ´ leads to a rise in ethane levels in natural gas as verified by the review of data taken at a specific location within the gas system over the years 2015 2020 and 2022. Using measurements of natural gas composition the effectiveness of the steam hydrocarbon reforming process was simulated in the Gibbs reactor via Aspen HYSYS. The simulations confirmed that as the concentration of ethane in the natural gas increased the amount of hydrogen produced and the heat required for reactions in the reformer also increased. This article aims to analyze the influence of the changes in natural gas quality in the Polish transmission network caused by changes in supply structures on the mass and heat balance of the theoretical steam reforming reactor. Nowadays the chemical composition of natural gas may be significantly different from that assumed years ago at the plant’s design stage. The consequence of such a situation may be difficulties in operating especially when controlling the quantity of incoming natural gas to the reactor based on volumetric flow without considering changes in chemical composition.

Transforming Europe into a climate neutral economy and society by 2050 requires extraordinary efforts and the mobilisation of all sectors and economic actors coupled with all the creative and brain power one can imagine. Each sector has to fundamentally rethink the way it operates to ensure it can be transformed towards this new net-zero paradigm without jeopardising other environmental and societal objectives both within the EU and globally. Given the scale of the transformation ahead our ability to meet climate neutrality targets directly depends on our ability to innovate. In this context Research & Innovation programmes have a key role to play and it is crucial to ensure they are fit for purpose and well equipped to support the next wave of breakthrough innovations that will be required to achieve climate neutrality in the EU and globally by 2050. The objective of this study is to contribute to these strategic planning discussions by not only identifying high-risk and high-impact climate mitigation solutions but most importantly look beyond individual solutions and consider how systemic interactions of climate change mitigation approaches can be integrated in the development of R&I agendas.

The rapid growth of global aviation emissions has significantly impacted the environment leading to an urgent need to use carbon reduction methods. This paper analyzes global aviation’s carbon dioxide (CO2) N2O and CH4 emission changes under different hydrogen energy application paths. The global warming potential over a 100-year period (GWP100) method is used to convert the emissions of N2O and CH4 into CO2-equivalent. Here we report the results: if the global aviation industry begins using hydrogen turbine engines by 2040 it could reduce cumulative CO2-equivalent emissions by 2.217E+10 tons by 2080 which is 2.12% higher than starting hydrogen fuel cell engines in 2045. However adopting hydrogen fuel cell engines 10 years earlier shows greater reduction capabilities than hydrogen turbine engines achieving an accumulated reduction of 3.006E+10 tons of CO2-equivalent emissions. Therefore the timing of adoption notably affects hydrogen fuel cell engines more than hydrogen turbine engines. Delaying adoption makes hydrogen fuel cell engines’ performance lag hydrogen turbine engines.

National Nuclear Laboratory (NNL) is aiming to demonstrate through a research and development programme that nuclear enabled hydrogen can be used to support future clean energy systems. Demonstrating the safe operation of hydrogen facilities co-generating with a nuclear reactor will be key to enabling the deployment and success of nuclear enabled hydrogen technologies in the future. During the deployment continuity of supply will be paramount and possibly requires inter-seasonal storage. Co-generation is a means of using a source of energy in this case a nuclear reactor to efficiently produce power and thermal energy. Since a great deal of the heat energy is lost to the environment in a power plant making use of wasted energy for other useful output like the production of hydrogen and direct heating would be advantageous to plant economics and energy system flexibility. The civil nuclear industry is regulated around the world. This approach ensures that all the activities related to the production of power from nuclear and the hazards associated with ionising radiation are controlled in a manner which protects workers members of the public property and the environment. Nuclear safety assessments follow a rigorous process and are required as part of the Nuclear Site Licence. A fundamental requirement which is cited in the UK legislation is that the risks associated with all activities at the licensed site be reduced to As Low As Reasonably Practicable (ALARP). The principle places a requirement on duty holders to implement measures to reduce risk where doing so is considered reasonable and proportionate. The inclusion of risks for hazardous materials associated with the hydrogen production facilities need to be considered and this requires harmonisation of two different safety and regulatory governance regimes which have not previously interacted in this way. The safety demonstration for nuclear facilities is provided through the Safety Case.

The imperative to address traditional energy crises and environmental concerns has accelerated the need for energy structure transformation. However the variable nature of renewable energy poses challenges in meeting complex practical energy requirements. To address this issue the construction of a multifunctional large-scale stationary energy storage system is considered an effective solution. This paper critically examines the battery and hydrogen hybrid energy storage systems. Both technologies face limitations hindering them from fully meeting future energy storage needs such as large storage capacity in limited space frequent storage with rapid response and continuous storage without loss. Batteries with their rapid response (90%) excel in frequent short-duration energy storage. However limitations such as a selfdischarge rate (>1%) and capacity loss (~20%) restrict their use for long-duration energy storage. Hydrogen as a potential energy carrier is suitable for large-scale long-duration energy storage due to its high energy density steady state and low loss. Nevertheless it is less efficient for frequent energy storage due to its low storage efficiency (~50%). Ongoing research suggests that a battery and hydrogen hybrid energy storage system could combine the strengths of both technologies to meet the growing demand for large-scale long-duration energy storage. To assess their applied potentials this paper provides a detailed analysis of the research status of both energy storage technologies using proposed key performance indices. Additionally application-oriented future directions and challenges of the battery and hydrogen hybrid energy storage system are outlined from multiple perspectives offering guidance for the development of advanced energy storage systems.

Rapid urbanization and globalization are causing a rise in the energy demand within the residential sector. Currently majority of the energy demand for the residential sector being supplied from fossil fuels these sources account for greenhouse gas emissions responsible for anthropogenic-driven climate change. About 85 % of the world’s energy demands are being met by non-renewable sources of energy. An immediate need to shift towards renewable energy sources to generate electricity is the need of the hour. These long-standing renewable energy sources including solar hydropower and wind energy have been crucial pillars of sustainable energy for years. However as their implementation has matured we are increasingly recognizing their limitations. Issues such as the scarcity of suitable locations and the significant carbon footprint associated with constructing renewable energy infrastructure are becoming more apparent. Hydrogen has been found to play a vital role as an energy carrier in framing the energy picture in the 21st century. Currently about 1 % of the global energy demands are being met by hydrogen energy harnessed through renewable methods. Its low carbon emissions when compared to other methods lower comparative production costs and high energy efficiency of 40–60 % make it a suitable choice. Integrating hydrogen production systems with other renewable source of energy such as solar and wind energy have been discussed in this review in detail. With the concepts of green buildings or net zero energy buildings gaining attraction integration of hydrogen-based systems within residential and office sectors through the use of devices such as micro–Combined Heat and Power devices (mCHP) have proven to be effective and efficient. These devices have been found to save the consumed energy by 22 % along with an effective reduction in carbon emissions of 18 % when used in residential sectors. Using the rejected energy from other processes these mCHP devices can prove to be vital in meeting the energy demands of the residential sector. Through the support of government schemes mCHP devices have been widely used in countries such as Japan and Finland and have benefitted from the same. Hydrogen storage is critical for efficient operation of the integrated renewable systems as improper storage of the hydrogen produced could lead to human and environmental disasters. Using boron hydrides or ammonia (121 kg H2/m3 ) or through organic carriers hydrogen can be stored safely and easily regenerated without loss of material. A thorough comparison of all the renewable sources of energy that are used extensively is required to evaluate the merits of using hydrogen as an energy carrier which has been addressed in this review paper. The need to address the research gap in application of mCHP devices in the residential sector and the benefits they provide has been addressed in this review. With about 2500 GW of energy ready to be harnessed through the mCHP devices globally the potential of mCHP systems globally are discussed in detail in this paper. This review discusses challenges and solutions to hydrogen production storage and ways to implement hydrogen technology in the residential sector. This review allows researchers to build a renewable alternative with hydrogen as a clean energy vector for generating electricity in residential systems.

This paper intends to give an impression of new technologies and processes that are in development for application to achieve decarbonization and about which less or no experience on associated hazards exists in the process industry. More or less an exception is hydrogen technology because its hazards are relatively known and there is industry experience in handling it safely but problems will arise when it is produced stored and distributed on a large scale. So when its use spreads to communities and it becomes as common as natural gas now measures to control the risks will be needed. And even with hydrogen surprise findings have been shown lately e.g. its BLEVE behavior when in a liquified form stored in a vessel heated externally. Substitutes for hydrogen are not without hazard concern either. The paper will further consider the hazards of energy storage in batteries and the problems to get those hazards under control. Relatively much attention will be paid to the electrification of the process industry. Many new processes are being researched which given green energy will be beneficial to reduce greenhouse gases and enhance sustainability but of which hazards are rather unknown. Therefore as last chapter the developments with respect to the concept of hazard identification and scenario definition will be considered in quite detail. Improvements in that respect are also being possible due to the digitization of the industry and the availability of data and considering the entire life cycle all facilitated by the data model standard ISO 15926 with the scope of integration of life-cycle data for process plants including oil and gas production facilities. Conclusion is that the new technologies and processes entail new process and personal hazards and that much effort is going into renewal but safety analyses are scarce. Right in a period of process renewal attention should be focused on possibilities to implement inherently safer design.

Climate change and environmental degradation are growing concerns in today’s society which has led to greater awareness and responsibility regarding the need to adopt sustainable practices. The European Union has established the goal of achieving climate neutrality by 2050 which implies a significant reduction in greenhouse gas emissions in all sectors. To achieve this goal renewable energies the circular economy and energy efficiency are being promoted. A major source of emissions is the use of fossil fuels in different types of ships (from transport ships to those used by national navies). Among these it highlights the growing interest of the defense sector in trying to reduce these emissions. The Spanish Ministry of Defense is also involved in this effort and is taking steps to reduce the carbon footprint in military operations and improve sustainability in equipment acquisition and maintenance. The objective of this study is to identify the most promising alternative fuel among those under development for possible implementation on Spanish Navy ships in order to reduce greenhouse gas emissions and improve its capabilities. To achieve this a multi-criteria decision-making method will be used to determine the most viable fuel option. The data provided by the officers of the Spanish Navy is of great importance thanks to their long careers in front of the ships. The analysis revealed that hydrogen was the most suitable fuel with the highest priority ahead of LNG and scored the highest in most of the sections of the officials’ ratings. These fuels are less polluting and would allow a significant reduction in emissions during the navigation of ships. However a further study would also have to be carried out on the costs of adapting to their use and the safety of their use.

To meet the new regulation for the deployment of alternative fuels infrastructure which sets targets for electric recharging and hydrogen refuelling infrastructure by 2025 or 2030 a large infrastructure comprising trucksuitable hydrogen refuelling stations will soon be required. However further standardisation is required to support the uptake of hydrogen for heavy-duty transport for Europe’s green energy future. Hydrogen-powered vehicles require pure hydrogen as some contaminants can reduce the performance of the fuel cell even at very low levels. Even if previous projects have paved the way for the development of the European quality infrastructure for hydrogen conformity assessment sampling systems and methods have yet to be developed for heavy-duty hydrogen refuelling stations (HD-HRS). This study reviews different aspects of the sampling of hydrogen at heavy-duty hydrogen refuelling stations for purity assessment with a focus on the current and future specifications and operations at HD-HRS. This study describes the state-of-the art of sampling systems currently under development for use at HD-HRS and highlights a number of aspects which must be taken into consideration to ensure safe and accurate sampling: risk assessment for the whole sampling exercise selection of cylinders methods to prepare cylinders before the sampling filling pressure and venting of the sampling systems.

Hydrogen energy is critical in replacing fossil fuels and achieving net zero carbon emissions by 2050. Three measures can be implemented to promote hydrogen energy: reduce the cost of low-carbon hydrogen through technological improvements increase the production capacity of low-carbon hydrogen by stimulating investment and enhance hydrogen use as an energy carrier and in industrial processes by demand-side policies. This article examines how effective these measures are if successfully implemented in boosting the hydrogen market and reducing global economy-wide carbon emissions using a global computable general equilibrium model. The results show that all the measures increase the production and use of low-carbon hydrogen whether implemented alone or jointly. Notably the emissions reduced by joint implementation of all the measures in 2050 become 2.5 times the sum of emissions reduced by individual implementation indicating a considerable multiplier effect. This suggests supply and demand side policies be implemented jointly to maximize their impact on reducing emissions.

The war in Ukraine caused Europe to more than double its imports of liquefied natural gas (LNG) in only one year. In addition imported LNG remains a crucial source of energy for resource-poor countries such as Japan where LNG imports satisfy about a quarter of the country’s primary energy demand. However an increasing number of countries are formulating stringent decarbonization plans. Liquefied hydrogen and liquefied ammonia coupled with carbon capture and storage (LH2-CCS LNH3-CCS) are emerging as the front runners in the search for low-carbon alternatives to LNG. Yet little is currently known about the full environmental profile of LH2-CCS and LNH3-CCS because several characteristics of the two alternatives have only been analyzed in isolation in previous work. Here we show that the potential of these fuels to reduce greenhouse gas (GHG) emissions throughout the supply chain is highly uncertain. Our best estimate is that LH2-CCS and LNH3-CCS can reduce GHG emissions by 25%–61% relative to LNG assuming a 100 year global warming potential. However directly coupling LNG with CCS would lead to substantial GHG reductions on the order of 74%. Further under certain conditions emissions from LH2-CCS and LNH3-CCS could exceed those of LNG by up to 44%. These results question the suitability of LH2-CCS and LNH3-CCS for stringent decarbonization purposes.

The utilization of hydrogen fuel in gas turbines brings significant changes to the thermophysical properties of flue gas including higher specific heat capacities and an enhanced steam content. Therefore hydrogen-fueled gas turbines are susceptible to health degradation in the form of steam-induced corrosion and erosion in the hot gas path. In this context the fault diagnosis of hydrogen-fueled gas turbines becomes indispensable. To the authors’ knowledge there is a scarcity of fault diagnosis studies for retrofitted gas turbines considering hydrogen as a potential fuel. The present study however develops an artificial neural network (ANN)-based fault diagnosis model using the MATLAB environment. Prior to the fault detection isolation and identification modules physics-based performance data of a 100 kW micro gas turbine (MGT) were synthesized using the GasTurb tool. An ANN-based classification algorithm showed a 96.2% classification accuracy for the fault detection and isolation. Moreover the feedforward neural network-based regression algorithm showed quite good training testing and validation accuracies in terms of the root mean square error (RMSE). The study revealed that the presence of hydrogen-induced corrosion faults (both as a single corrosion fault or as simultaneous fouling and corrosion) led to false alarms thereby prompting other incorrect faults during the fault detection and isolation modules. Additionally the performance of the fault identification module for the hydrogen fuel scenario was found to be marginally lower than that of the natural gas case due to assumption of small magnitudes of faults arising from hydrogen-induced corrosion.

We conduct a techno-economic assessment of two low-emissions steel production technologies and evaluate their deployment in emissions mitigation scenarios utilizing the MIT Economic Projection and Policy Analysis (EPPA) model. Specifically we assess direct reduced iron-electric arc furnace with carbon capture and storage (DRI-EAF with CCS) and H2-based direct reduced iron-electric arc furnace (H2 DRI-EAF) which utilizes low carbon hydrogen to reduce CO2 emissions. Our techno-economic analysis based on the current state of technologies found that DRI-EAF with CCS increased costs ~7% relative to the conventional steel technology. H2 DRI-EAF increased costs by ~18% when utilizing Blue hydrogen and ~79% when using Green hydrogen. The exact pathways for hydrogen production in different world regions including the extent of CCS and hydrogen deployment in steelmaking are highly speculative at this point. In illustrative scenarios using EPPA we find that using base cost assumptions switching from BF-BOF to DRI-EAF or scrap EAF can provide significant emissions mitigation within steelmaking. With further reductions in the cost of advanced steelmaking we find a greater role for DRI-EAF with CCS whereas reductions in both the cost of advanced steelmaking and hydrogen production lead to a greater role for H2 DRI-EAF. Our findings can be used to help decision-makers assess various decarbonization options and design economically efficient pathways to reduce emissions in the steel industry. Our cost evaluation can also be used to inform other energy-economic and integrated assessment models designed to provide insights about future decarbonization pathways.

This paper presents a new economic profitability model for a power-to-gas plant producing green hydrogen at the site of an existing wind power plant injected into the gas grid. The model is based on a 42 MW wind power plant for which an optimal electrolyzer of 10 MW was calculated based on the 2500 equivalent full load hours per year and the projection of electricity prices. The model is calculated on an hourly level for all variables of the 25 years of the model. With the calculated breakeven electricity price of 74.23 EUR/MWh and the price of green hydrogen production of 99.44 EUR/MWh in 2045 the wind power plant would produce 22410 MWh of green hydrogen from 31% of its total electricity production. Green hydrogen injected into the gas system would reduce the level of CO2 emissions by 4482 tons. However with the projected prices of natural gas and electricity the wind power plant would cover only 20% of the income generated by the electricity delivered to the grid by producing green hydrogen. By calculating different scenarios in the model the authors concluded that the introduction of a premium subsidy model is necessary to accelerate deployment of electrolyzers at the site of an existing wind power plant in order to increase the wind farm profitability.

Hydrogen production and storage in hybrid systems is a promising solution for sustainable energy transition decoupling the energy generation from its end use and boosting the deployment of renewable energy. Nonetheless the optimal and cost-effective design of hybrid hydrogen-based systems is crucial to tackle existing limitations in diffusion of these systems. The present study explores net-zero energy management via a multi-objective optimization algorithm for an outdoor test facility equipped with a hydrogen-based hybrid energy production system. Aimed at enabling efficient integration of hydrogen fuel cell system the proposed solution attempts to maximize the renewable factor (RF) and carbon mitigation in the hybrid system as well as to minimize the grid dependency and the life cycle cost (LCC) of the system. In this context the techno-enviroeconomic optimization of the hybrid system is conducted by employing a statistical approach to identify optimal design variables and conflictive objective functions. To examine interactions in components of the hybrid system a series of dynamic simulations are carried out by developing a TRNSYS code coupled with the OpenStudio/EnergyPlus plugin. The obtained results indicate a striking disparity in the monthly RF values as well as the hydrogen production rate and therefore in the level of grid dependency. It is shown that the difference in LCC between optimization scenarios suggested by design of experiments could reach $15780 corresponding to 57% of the mean initial cost. The LCOE value yielded for optimum scenarios varies between 0.389 and 0.537 $/kWh. The scenario with net-zero target demonstrates the lowest LCOE value and the highest carbon mitigation i.e. 828 kg CO2/yr with respect to the grid supply case. However the LCC in this scenario exceeds $57370 which is the highest among all optimum scenarios. Furthermore it was revealed that the lowest RF in optimal scenarios is equal to 66.2% and belongs to the most economical solution.