Publications

In order to study the flow blending and transporting process of hydrogen that injects into the natural gas pipelines a three-dimensional T-pipe blending model is established and the flow characteristics are investigated systematically by the large eddy simulation (LES). Firstly the mathematical formulation of hydrogen-methane blending process is provided and the LES method is introduced and validated by a benchmark gas blending model having experimental data. Subsequently the T-pipe blending model is presented and the effects of key parameters such as the velocity of main pipe hydrogen blending ratio diameter of hydrogen injection pipeline diameter of main pipe and operating pressure on the hydrogen-methane blending process are studied systematically. The results show that under certain conditions the gas mixture will be stratified downstream of the blending point with hydrogen at the top of the pipeline and methane at the bottom of the pipeline. For the no-stratified scenarios the distance required for uniformly mixing downstream the injection point increases when the hydrogen mixing ratio decreases the diameter of the hydrogen injection pipe and the main pipe increase. Finally based on the numerical results the underlying physics of the stratification phenomenon during the blending process are explored and an indicator for stratification is proposed using the ratio between the Reynolds numbers of the natural gas and hydrogen.

The current study comprehensively examines the application of wave tidal and undersea current energy sources of Turkiye for green hydrogen fuel production and cost analysis. The estimated potential capacity of each city is derived from official data and acceptable assumptions and is subject to discussion and evaluation in the context of a viable hydrogen economy. According to the findings the potential for green hydrogen generation in Turkiye is projected to be 7.33 million tons using a proton exchange membrane electrolyser (PEMEL). Cities with the highest hydrogen production capacities from marine applications are Mugla Izmir Antalya and Canakkale with 998.10 kt 840.31 kt 605.46 kt and 550.42 kt respectively. The study calculations obviously show that there is a great potential by using excess power in producing hydrogen which will result in an economic value of 3.01 billion US dollars. This study further helps develop a detailed hydrogen map for every city in Turkiye using the identified potential capacities of renewable energy sources and the utilization of electrolysers to make green hydrogen by green power. The potentials and specific capacities for every city are also highlighted. Furthermore the study results are expected to provide clear guidance for government authorities and industries to utilize such a potential of renewable energy for investment and promote clean energy projects by further addressing concerns caused by the usage of carbon-based (fossil fuels dependent) energy options. Moreover green hydrogen production and utilization in every sector will help achieve the national targets for a net zero economy and cope with international targets to achieve the United Nation's sustainable development goals.

The energy sector constitutes a dynamic and complex system indicating that its actions are influenced not just by its individual components but also by the emergent behavior resulting from interactions among them. Moreover there are crucial limitations of previous approaches for addressing the sustainability challenge of the energy sector. Changing transforming and integrating paradigms are the most relevant leverage points for transforming a given system. In other words nowadays the integration of new predominant paradigms in order to provide a unified framework could aim at this actual transformation looking for a sustainable future. This research aims to develop a new unified framework for the integration of the following three paradigms: (1) Sustainability (2) Complexity and (3) Systems Thinking which will be applied to achieving sustainable energy production (using hydrogen production as a case study). The novelty of this work relies on providing a holistic perspective through the integration of the aforementioned paradigms considering the multiple and complex interdependencies among the economy the environment and the economy. For this purpose an integrated seven-stage approach is introduced which explores from the starting point of the integration of paradigms to the application of this integration to sustainable energy production. After applying the Three-Paradigm approach for sustainable hydrogen production as a case study 216 feedback loops are identified due to the emerged complexity linked to the analyzed system. Additionally three system dynamics-based models are developed (by increasing the level of complexity) as part of the application of the Three-Paradigm approach. This research can be of interest to a broad professional audience (e.g. engineers policymakers) as looks into the sustainability of the energy sector from a holistic perspective considering a newly developed Three-Paradigm model considering complexity and using a Systems Thinking approach.

While hydrogen is regularly discussed as a possible option for storing regenerative energies its low minimum ignition energy and broad range of explosive concentrations pose safety challenges regarding hydrogen storage and there are also challenges related to hydrogen production and transport and at the point of use. A risk assessment of the whole hydrogen energy system is necessary to develop hydrogen utilization further. Here we concentrate on the most important hydrogen storage technologies especially high-pressure storage liquid hydrogen in cryogenic tanks methanol storage and salt cavern storage. This review aims to study the most recent research results related to these storage techniques by describing typical sensors and explosion protection measures thus allowing for a risk assessment of hydrogen storage through these technologies.

The growing emphasis on renewable energy highlights hydrogen’s potential as a clean energy carrier. However traditional hydrogen production methods contribute significantly to carbon emissions. This review examines the integration of carbon capture and storage (CCS) technologies with hydrogen production processes focusing on their ability to mitigate carbon emissions. It evaluates various hydrogen production techniques including steam methane reforming electrolysis and biomass gasification and discusses how CCS can enhance environmental sustainability. Key challenges such as economic technical and regulatory obstacles are analyzed. Case studies and future trends offer insights into the feasibility of CCS–hydrogen integration providing pathways for reducing greenhouse gases and facilitating a clean energy transition.

Accelerating the transition to a cleaner global energy system is essential for tackling the climate crisis and green hydrogen energy systems hold significant promise for integrating renewable energy sources. This paper offers a thorough evaluation of green hydrogen’s potential as a groundbreaking alternative to achieve near-zero greenhouse gas (GHG) emissions within a renewable energy framework. The paper explores current technological options and assesses the industry’s present status alongside future challenges. It also includes an economic analysis to gauge the feasibility of integrating green hydrogen providing a critical review of the current and future expectations for the levelized cost of hydrogen (LCOH). Depending on the geographic location and the technology employed the LCOH for green hydrogen can range from as low as EUR 1.12/kg to as high as EUR 16.06/kg. Nonetheless the findings suggest that green hydrogen could play a crucial role in reducing GHG emissions particularly in hard-to-decarbonize sectors. A target LCOH of approximately EUR 1/kg by 2050 seems attainable in some geographies. However there are still significant hurdles to overcome before green hydrogen can become a cost-competitive alternative. Key challenges include the need for further technological advancements and the establishment of hydrogen policies to achieve cost reductions in electrolyzers which are vital for green hydrogen production.

The decarbonization of industrial process heat is one of the bigger challenges of the global energy transition. Process heating accounts for about 20% of final energy demand in Germany and the situation is similar in other industrialized nations around the globe. Process heating is indispensable in the manufacturing processes of products and materials encountered every day ranging from food beverages paper and textiles to metals ceramics glass and cement. At the same time process heating is also responsible for significant greenhouse gas emissions as it is heavily dependent on fossil fuels such as natural gas and coal. Thus process heating needs to be decarbonized. This review article explores the challenges of decarbonizing industrial process heat and then discusses two of the most promising options the use of electric heating technologies and the substitution of fossil fuels with low-carbon hydrogen in more detail. Both energy carriers have their specific benefits and drawbacks that have to be considered in the context of industrial decarbonization but also in terms of necessary energy infrastructures. The focus is on high-temperature process heat (>400 ◦C) in energy-intensive basic materials industries with examples from the metal and glass industries. Given the heterogeneity of industrial process heating both electricity and hydrogen will likely be the most prominent energy carriers for decarbonized high-temperature process heat each with their respective advantages and disadvantages.

Grids require electricity storage. Two emerging storage technologies are battery storage (BS) and green hydrogen storage (GHS) (hydrogen produced and compressed with clean-renewable electricity stored then returned to electricity with a fuel cell). An important question is whether GHS alone decreases system cost versus BS alone or BS+GHS. Here energy costs are modeled in 145 countries grouped into 24 regions. Existing conventional hydropower (CH) storage is used along with new BS and/or GHS. A method is developed to treat CH for both baseload and peaking power. In four regions only CH is needed. In five CH+BS is lowest cost. Otherwise CH+BS+GHS is lowest cost. CH+GHS is never lowest cost. A metric helps estimate whether combining GHS with BS reduces cost. In most regions merging (versus separating) grid and non-grid hydrogen infrastructure reduces cost. In sum worldwide grid stability may be possible with CH+BS or CH+BS+GHS. Results are subject to uncertainties.

Green hydrogen has been considered a promising alternative to fossil fuels in chemical and energy applications. In this study a life cycle analysis is conducted for green hydrogen production sourced with a mixture of renewable energy sources (50 % solar and 50 % wind energy). Two advanced technologies of alkaline electrolysis are selected and compared for hydrogen production: pressurised alkaline electrolyser and capillary-fed alkaline electrolyser. The different value chain stages were assessed in SimaPro enabling the assessment of the environmental impacts of a green hydrogen production project with 60 MW capacity and 20 years lifetime. The results evaluate the environmental impacts depending on the components construction and operation requirements. The results demonstrated that capillary-fed alkaline electrolyser technology has lower potential environmental impacts by around 17 % than pressurised alkaline electrolyser technology for all the process stages. The total global warming potential was found to be between 1.98 and 2.39 kg of carbon dioxide equivalent per kg of hydrogen. This study contributes to the electrolysers industry and the planning of green hydrogen projects for many applications towards decarbonization and sustainability.

Hydrogen is gaining importance to decarbonize the energy system and tackle the climate crisis. This exploratory study analyzes three focus groups with representatives from relevant organizations in a Northern German region that has unique beneficial characteristics for the transition to a hydrogen economy. Based upon this data (1) a category system of innovation adoption barriers for hydrogen technologies is developed (2) decision levels associated with the barriers are identified (3) detailed insights on how decision levels contribute to the adoption barriers are provided and (4) the barriers are evaluated in terms of their importance. Our analysis adds to existing literature by focusing on short-term barriers and exploring relevant decision levels and their associated adoption barriers. Our main results comprise the following: flaws in the funding system complex approval procedures lack of networks and high costs contribute to hydrogen adoption barriers. The (Sub-)State level is relevant for the uptake of the hydrogen economy. Regional entities have leeway to foster the hydrogen transition especially with respect to the distribution infrastructure. Funding policy technological suitability investment and operating costs and the availability of distribution infrastructure and technical components are highly important adoption barriers that alone can impede the transition to a hydrogen economy.

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.

This paper investigates hydrogen’s potential to accelerate the energy transition in hardto-abate sectors such as steel petrochemicals glass cement and paper. The goal is to assess how hydrogen produced from renewable sources can foster both industrial decarbonization and the expansion of renewable energy installations especially solar and wind. Hydrogen’s dual role as a fuel and a chemical agent for process innovation is explored with a focus on its ability to enhance energy efficiency and reduce CO2 emissions. Integrating hydrogen with continuous industrial processes minimizes the need for energy storage making it a more efficient solution. Advances in electrolysis achieving efficiencies up to 60% and storage methods consuming about 10% of stored energy for compression are discussed. Specifically in the steel sector hydrogen can replace carbon as a reductant in the direct reduced iron (DRI) process which accounts for around 7% of global steel production. A next-generation DRI plant producing one million tons of steel annually would require approximately 3200 MW of photovoltaic capacity to integrate hydrogen effectively. This study also discusses hydrogen’s role as a co-fuel in steel furnaces. Quantitative analyses show that to support typical industrial plants hydrogen facilities of several hundred to a few thousand MW are necessary. “Virtual” power plants integrating with both the electrical grid and energy-intensive systems are proposed highlighting hydrogen’s critical role in industrial decarbonization and renewable energy growth.

As a clean energy source hydrogen not only helps to reduce the use of fossil fuels but also promotes the transformation of energy structure and sustainable development. This paper firstly introduces the development status of green hydrogen at home and abroad and then focuses on several advanced green hydrogen production technologies. Then the advantages and shortcomings of different green hydrogen production technologies are compared. Among them the future source of hydrogen tends to be electrolysis water hydrogen production. Finally the challenges and application prospects of the development process of green hydrogen technology are discussed and green hydrogen is expected to become an important part of realizing sustainable global energy development.

The study investigates the potential of transitioning Iraq a nation significantly dependent on fossil fuels toward a green hydrogen-based energy system as a pathway to achieving sustainable economic resilience. As of 2022 Iraqi energy supply is over 90% reliant on hydrocarbons which also account for 95% of the country foreign exchange earnings. The global energy landscape is rapidly shifting towards cleaner alternatives and the volatility of oil prices has made it imperative for the country to diversify its energy sources. Green hydrogen produced through water electrolysis powered by renewable energy sources such as solar and wind offers a promising alternative given country vast renewable energy potential. The analysis indicates that with strategic investments in green hydrogen infrastructure the country could reduce its hydrocarbon dependency by 30% by the year 2030. This transition could not only address pressing environmental challenges but also contribute to the economic stability of the country. However the shift to green hydrogen is not without significant challenges including water scarcity technological limitations and the necessity for a robust regulatory framework. The findings underscore the importance of international partnerships and supportive policies in facilitating this energy transition. Adopting renewable energy and green hydrogen technologies the country has the potential to become a leader in sustainable energy within the region. This shift would not only drive economic growth and energy security but also contribute to global efforts towards environmental sustainability positioning country favorably in a future low-carbon economy.

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.

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.

Despite the number of works on the techno-economics of offshore green hydrogen production there is a lack of research on the design of floating platforms to concomitantly support hydrogen production facilities and wind power generation equipment. Indeed previous studies on offshore decentralised configuration for hydrogen production implicitly assume that a floating platform designed for wind power generation (FOWT) can be also suitable as a floating wind hydrogen system (FWHS). This work proposes a novel design for an offshore decentralised FWHS and analyses the effects of the integration of the hydrogen facilities on the platform’s dynamics and how this in turn affects the performances of the wind turbine and the hydrogen equipment. Our findings indicate that despite the reduction in platform’s stability the performance of the wind turbine is barely affected. Regarding the hydrogen system our results aim at contributing to further assessment and design of this equipment for offshore conditions.

The current study seeks to greenhouse gas emissions reduction in an existing engine under dual-fuel combustion fueled with diesel fuel and natural gas due to great concerns about global warming. This simulation study focuses on the identification of areas prone to the formation of greenhouse gas emissions in engine cylinders. The simulation results of dual-fuel combustion confirmed that the possibility of incomplete combustion and the formation of greenhouse gas emissions in high levels are not far from expected. Therefore an efficient combustion strategy along with replacing natural gas with hydrogen was considered. Only changing the combustion mode to reactivity-controlled compression ignition has led to the improvement of the natural gas burning rate and guarantees a 32 % reduction in unburned methane and 50 % carbon monoxide. To further reduce engine emissions while changing the combustion mode a part of natural gas replacement with hydrogen to the complete elimination of it was evaluated. Increasing the share of hydrogen energy in the intake air-natural gas mixture up to 54 % without exhaust gas recirculation does not lead to diesel knock. Moreover improvement of engine load and efficiency can be achieved by up to 18 % and 6 % respectively. Natural gas consumption can be reduced by up to 67 %. Meanwhile the unburned methane and carbon dioxide mass known as greenhouse gas emissions can be reduced to less than 1 % and up to 50 % respectively. Continued replacement of natural gas with hydrogen until its complete elimination guarantees a reduction of 92000 cubic meters of natural gas per year in one engine cylinder. Although the engine efficiency and load face a decrease of 0.8 % and 5.0 % respectively; the amount of carbon dioxide can be decreased by about 4.5 times. Unburned methane carbon monoxide and nitrogen oxides can be reduced to below the relevant EURO VI range while the amount of unburned hydrogen compared to the hydrogen entering the engine is about 0.5 %.

In confined spaces hydrogen released with low momentum tends to accumulate in a layer below the ceiling; the concentration in this layer rises and can rapidly enter the flammability range. In this context ventilation is a key safety equipment to prevent the formation of such flammable volumes. To ensure its well-sizing to each specific industrial context it is necessary to dispose of reliable engineering models. Currently the existing engineering models dealing with the buoyancy-driven H2 dispersion in a ventilated enclosure mainly focus on the natural-ventilation phenomenon. However forced ventilation is in some situations more adapted to the industrial context as the wind direction and intensity remains constant and under control. Therefore two existing wind-assisted ventilation models elaborated by Hunt and Linden [1] and Lowesmith et al. [2] were tested on forced ventilation applications. The main assumption consists in assuming a blowing ventilation system rather than a suction system as the composition and velocity of the entering air are known. The fresh air enters the down opening and airhydrogen mixture escapes through the upper one. The adapted models are then validated with experimental data releasing helium rather than hydrogen. Experiments are conducted on a 1-m3 ventilated box controlling the release and ventilation rates. The agreement between both analytical and experimental results is discussed from the different comparisons performed.

To consider an appropriate evaluation method for hydrogen compatibility slow strain rate tensile (SSRT) tests were conducted on high strength piping materials cold-worked type 316 austenitic stainless steel (SUS316CW) and iron-based superalloy A286 used in hydrogen stations for two years.<br/>SUS316CW used at room temperature in 82 MPa gaseous hydrogen contained 7.8 mass ppm hydrogen. The SSRT test of SUS316CW was conducted in nitrogen at -40 °C. The fracture surface showed dimples and no hydrogen embrittlement behavior was observed. While the SSRT test of SUS316CW in 70 MPa gaseous hydrogen at -40 °C showed a slight decrease in reduction area and a brittle fracture morphology in the outer layer. This was considered to be the effect of high-pressure gaseous hydrogen during the SSRT test in addition to the pre-contained hydrogen.<br/>A286 used at -40 °C in 82 MPa gaseous hydrogen contained negligible hydrogen (0.14 mass ppm). SSRT tests were conducted at 150 °C in 70 MPa gaseous hydrogen and in air and showed a low relative reduction in area (RRA) value. To investigate the decrease in the RRA we switched the gas from hydrogen to air in the middle of the SSRT test and closely examined the RRA values and fracture morphology including side cracks. The hydrogen embrittlement was found to originate from the elastic deformation region. Stress cycling in the elastic deformation region also accelerated the effect of hydrogen. These were attributed to an increase in the lattice hydrogen content. While in the plastic deformation region hydrogen trapped in the defects and hydrogen through the generated surface cracks increased the hydrogen content at the crack tips reducing the RRA value. And there was a good correlation between the crack lengths and RRA values.<br/>Then hydrogen embrittlement mechanism depends on the operating conditions (stress and temperature) of the material and evaluating the hydrogen compatibility of materials by controlling their hydrogen content and strain according to the service environment is desirable.

This study investigates the light gas dispersion behaviour in a maintenance garage with natural or forced ventilation. A scaled-down garage model (0.71 m high 3.07 m long and 3.36 m wide) equipped with gas and velocity sensors was used in the experiments. The enclosure had four rectangular vents at the ceiling and four at the bottom on two opposing side walls. The experiments were performed by injecting helium continuously through a 1-mm downward-facing nozzle until a steady state was reached. The sensitivity parameters included helium injection rate the elevation of the injection nozzle and forced flow speeds. Exhaust fans were placed at one or all of the top vent(s) to mimic forced ventilation. Numerical simulations conducted using GOTHIC a general-purpose thermal-hydraulic code and calculations with engineering models were compared with experimental measurements to determine the relative suitability of each approach to predict the light gas transport behaviour. The GOTHIC simulations captured the trends of the helium distribution gas movement in the enclosure and the passive vent flows reasonably well. Lowesmith’s model predictions for the helium transients in the upper uniform layer were also in good agreement with the natural venting experiments.

This study develops a framework for designing hydrogen supply chains (HSC) in island territories using Mixed Integer Linear Programming (MILP) with a multi-period approach. The framework minimizes system costs greenhouse gas emissions and a risk-based index. Corsica is used as a case study with a Geographic Information System (GIS) identifying hydrogen demand regions and potential sites for production storage and distribution. The results provide an optimal HSC configuration for 2050 specifying the size location and technology while accounting for techno-economic factors. This work integrates the unique geographical characteristics of islands using a GIS-based approach incorporates technology readiness levels and utilizes renewable electricity from neighboring regions. The model proposes decentralized configurations that avoid hydrogen transport between grids achieving a levelized cost of hydrogen (LCOH) of €8.54/kg. This approach offers insight into future options and incentive mechanisms to support the development of hydrogen economies in isolated territories.

The large-scale integration of renewable energy sources leads to daily and seasonal mismatches between supply and demand and the curtailment of wind power. Hydrogen produced from surplus wind power offers an attractive solution to these challenges. In this paper we consider a large offshore wind park and analyze the need for hydrogen storage at the onshore and offshore sides of a large transportation pipeline that connects the wind park to the mainland. The results show that the pipeline with line pack storage though important for day-to-day fluctuations will not offer sufficient storage capacity to bridge seasonal differences. Furthermore the results show that if the pipeline is sufficiently sized additional storage is only needed on one side of the pipeline which would limit the needed investments. Results show that the policy which determines what part of the wind power is fed into the electricity grid and what part is converted into hydrogen has a significant influence on these seasonal storage needs. Therefore investment decisions for hydrogen systems should be made by considering both the onshore and offshore storage requirements in combination with electricity transport to the mainland.

Hydrogen is experiencing an unprecedented global hype. Hydrogen is globally discussed as a possible future energy carrier and regarded as the urgently needed building block for the much needed carbon-neutral energy transition of hard-to-abate sectors to mitigate the effects of global warming. This article provides synthesised measurable sustainability criteria for analysing green hydrogen production proposals and strategies. Drawn from expert interviews and an extensive literature review this article proposes that a sustainable hydrogen production should consider six impact categories; Energy transition Environment Basic needs Socio-economy Electricity supply and Project planning. The categories are broken down into sixteen measurable sustainability criteria which are determined with related indicators. The article concludes that low economic costs can never be the only decisive criterion for the hydrogen production; social aspects must be integrated along the entire value chain. The compliance with the criteria may avoid social and ecological injustices in the planning of green hydrogen projects and increases inter alia the social welfare of the affected population.

Hydrogen produced from renewable energy sources is a valuable energy carrier for linking growing renewable electricity generation with the hard-to-abate sectors such as cement steel glass chemical and ceramics industries. In this context this paper presents a new model of hydrogen production based on solar photovoltaics and wind energy with application to a real-world ceramics factory. For this task a novel multipurpose profit-maximizing model is implemented using GAMS. The developed model explores hydrogen production with multiple value streams that enable technical and economical informed decisions under specific scenarios. Our results show that it is profitable to sell the hydrogen produced to the gas grid rather than using it for self-consumption for low-gas-price scenarios. On the other hand when the price of gas is significantly high it is more profitable to use as much hydrogen as possible for self-consumption to supply the factory and reduce the internal use of natural gas. The role of electricity self-consumption has proven to be key for the project’s profitability as without this revenue stream the project would not be profitable in any analysed scenario.