Production & Supply Chain

Hydrogen produced via water electrolysis from renewable electricity is considered a key energy carrier to defossilize hard-to-electrify sectors. Solid oxide cells (SOC) based reactors can supply hydrogen not only in electrolysis but also in fuel cell mode when operating with (synthetic) natural gas or biogas at low conversion (polygeneration mode). However the scale-up of SOC reactors to the multi-MW scale is still a research topic. Strategies for transient operation depending on electricity intermittency still need to be developed. In this work a unique testing environment for SOC reactors allows reversible operation demonstrating the successful switching between electrolysis (− 75 kW) and polygeneration (25 kW) modes. Transient and steady state experiments show promising performance with a net hydrogen production of 53 kg day− 1 in SOEL operation with ca. − 75 kW power input. The experimental results validate the scaling approach since the reactor shows homogenous temperature profiles.

To achieve a more ecologically friendly energy transition by the year 2050 under the European “green” accord hydrogen has recently gained significant scientific interest due to its efficiency as an energy carrier. This paper focuses on large-scale hydrogen production systems based on marine renewable-energy-based wind turbines and tidal turbines. The paper reviews the different technologies of hydrogen production using water electrolyzers energy storage unit base hydrogen vectors and fuel cells (FC). The focus is on large-scale hydrogen production systems using marine renewable energies. This study compares electrolyzers energy storage units and FC technologies with the main factors considered being cost sustainability and efficiency. Furthermore a review of aging models of electrolyzers and FCs based on electrical circuit models is drawn from the literature and presented including characterization methods of the model components and the parameters extraction methods using a dynamic current profile. In addition industrial projects for producing hydrogen from renewable energies that have already been completed or are now in progress are examined. The paper is concluded through a summary of recent hydrogen production and energy storage advances as well as some applications. Perspectives on enhancing the sustainability and efficiency of hydrogen production systems are also proposed and discussed. This paper provides a review of behavioral aging models of electrolyzers and FCs when integrated into hydrogen production systems as this is crucial for their successful deployment in an ever-changing energy context. We also review the EU’s potential for renewable energy analysis. In summary this study provides valuable information for research and industry stakeholders aiming to promote a sustainable and environmentally friendly energy transition.

The research motivation of this paper is to utilize the large amount of energy wasted during the LNG (liquefied natural gas) gasification process and proposes a synergistic liquefied hydrogen (LH2) production and storage process scheme for LNG receiving station and methane reforming hydrogen production process - SMR-LNG combined liquefied hydrogen production system which uses the cold energy from LNG to pre-cool the hydrogen and subsequently uses an expander to complete the liquefaction of hydrogen. The proposed process is modeled and simulated by Aspen HYSYS software and its efficiency is evaluated and sensitivity analysis is carried out. The simulation results show that the system can produce liquefied hydrogen with a flow rate of 5.89t/h with 99.99% purity when the LNG supply rate is 50t/h. The power consumption of liquefied hydrogen is 46.6kWh/kg LH2; meanwhile the energy consumption of the HL subsystem is 15.9kWh/kg LH2 lower than traditional value of 17~19kWh/kg LH2. The efficiency of the hydrogen production subsystem was 16.9%; the efficiency of the hydrogen liquefaction (HL) subsystem was 29.61% which was significantly higher than the conventional industrial value of 21%; the overall energy efficiency (EE1) of the system was 56.52% with the exergy efficiency (EE2) of 22.2% reflecting a relatively good thermodynamic perfection. The energy consumption of liquefied hydrogen per unit product is 98.71 GJ/kg LH2.

Combining electrolytic hydrogen production with wind–photovoltaic power can effectively smooth the fluctuation of power and enhance the schedulable wind–photovoltaic power which provides an effective solution to solve the problem of wind–photovoltaic power accommodation. In this paper the optimization operation strategy is studied for the wind–photovoltaic power-based hydrogen production system. Firstly to make up for the deficiency of the existing research on the multi-state and nonlinear characteristics of electrolyzers the three-state and power-current nonlinear characteristics of the electrolyzer cell are modeled. The model reflects the difference between the cold and hot starting time of the electrolyzer and the linear decoupling model is easy to apply in the optimization model. On this basis considering the operation constraints of the electrolyzer hydrogen storage tank battery and other equipment the optimization operation model of the wind–photovoltaic power-based hydrogen production system is developed based on the typical scenario approach. It also considers the cold and hot starting time of the electrolyzer with the daily operation cost as the goal. The results show that the operational benefits of the system can be improved through the proposed strategy. The hydrogen storage tank capacity will have an impact on the operation income of the wind–solar hydrogen coupling system and the daily operation income will increase by 0.32% for every 10% (300 kg) increase in the hydrogen storage tank capacity.

The technique of producing hydrogen by utilizing green and renewable energy sources is called green hydrogen production. Therefore by implementing this technique hydrogen will become a sustainable and clean energy source by lowering greenhouse gas emissions and reducing our reliance on fossil fuels. The key beneft of producing green hydrogen by utilizing green energy is that no harmful pollutants or greenhouse gases are directly released throughout the process. Hence to guarantee all of the environmental advantages it is crucial to consider the entire hydrogen supply chain involving storage transportation and end users. Hydrogen is a promising clean energy source and targets plan pathways towards decarbonization and net-zero emissions by 2050. This paper has highlighted the techniques for generating green hydrogen that are needed for a clean environment and sustainable energy solutions. Moreover it summarizes an overview outlook and energy transient of green hydrogen production. Consequently its perspective provides new insights and research directions in order to accelerate the development and identify the potential of green hydrogen production.

The conversion of solar to chemical energy is one of the central processes considered in the emerging renewable energy economy. Hydrogen production from water splitting over particulate semiconductor catalysts has often been proposed as a simple and a cost-effective method for largescale production. In this review we summarize the basic concepts of the overall water splitting (in the absence of sacrificial agents) using particulate photocatalysts with a focus on their synthetic methods and the role of the so-called “co-catalysts”. Then a focus is then given on improving light absorption in which the Z-scheme concept and the overall system efficiency are discussed. A section on reactor design and cost of the overall technology is given where the possibility of the different technologies to be deployed at a commercial scale and the considerable challenges ahead are discussed. To date the highest reported efficiency of any of these systems is at least one order of magnitude lower than that deserving consideration for practical applications.

Hydrogen is a clean and environmentally friendly energy vector that can play an important role in meeting the world’s futureenergy needs. Therefore a comprehensive study of the potential for hydrogen production from solar energy could greatlyfacilitate the transition to a hydrogen economy. Because by knowing the exact amount of potential for solar hydrogenproduction the cost-effectiveness of its production can be compared with other methods of hydrogen production. Consideringthe above it can be seen that so far no comprehensive study has been done on finding the exact potential of solar hydrogenproduction in different stations of Iran and finding the most suitable station. Therefore in the present work for the first timeusing the HOMER and ArcGIS softwares the technical-economic study of solar hydrogen production at home-scale was done.The results showed that Jask station with a levelized cost of energy equal to $ 0.172 and annual production of 83.8 kg ofhydrogen is the best station and Darab station with a levelized cost of energy equal to $ 0.286 and annual production of 50.4 kgof hydrogen is the worst station. According to the results other suitable stations were Bushehr and Deyr and other unsuitablestations were Anzali and Khalkhal. Also in 102 under study stations 380 MW of solar electricity equivalent to 70.2 tons ofhydrogen was produced annually. Based on the geographic information system map it is clear that the southern half of Iranespecially the coasts of the Persian Gulf and the sea of Oman is suitable for hydrogen production and the northernnortheastern northwestern and one region in southern of Iran are unsuitable for hydrogen production. The authors of thisarticle hope that the results of the present work will help the energy policymakers to create strategic frameworks and a roadmapfor the production of solar hydrogen in Iran.

In this study the electrical electrochemical and thermodynamic performance of a PV/T electrolyzer system was investigated and the experimental results were verified with a numerical model. The annual amounts of electrical and thermal energy from the PV/T electrolyzer system were calculated as 556.8 kWh and 1912 kWh respectively. In addition the hydrogen production performance for the PV/T electrolyzer was compared with that of a PV electrolyzer system. The amount of hydrogen was calculated as 3.96 kg annually for the PV system while this value was calculated as 4.49 kg for the PV/T system. Furthermore the amount of hydrogen production was calculated as 4.59 kg for a 65 ◦C operation temperature. The electrical thermal and total energy efficiencies of the PV/T system which were obtained hourly on a daily basis were calculated and varied between 12–13.8% 36.1–45.2% and 49.1–58.4% respectively. The hourly exergy analyses were also carried out on a daily basis and the results showed that the exergy efficiencies changed between 13.8–14.32%. The change in the electrolysis voltage was investigated by changing the current and temperature in the ranges of 200–1600 mA/cm2 A and 30–65 ◦C respectively. While the current and the water temperature varied in the ranges of 400–2350 mA/cm2 and 28.1–45.8 ◦C respectively energy efficiency and exergy efficiency were in the ranges of 57.85–69.45% and 71.1–79.7% respectively.

This scientific article presents a developed model for optimising the scheduling of hydrogen production processes addressing the growing demand for efficient and sustainable energy sources. The study focuses on the integration of advanced scheduling techniques to improve the overall performance of the hydrogen electrolyser. The proposed model leverages constraint programming and satisfiability (CP-SAT) techniques to systematically analyse complex production schedules considering factors such as production unit capacities resource availability and energy costs. By incorporating real-world constraints such as fluctuating energy prices and the availability of renewable energy the optimisation model aims to improve overall operational efficiency and reduce production costs. The CP-SAT was applied to achieve more efficient control of the electrolysis process. The optimisation of the scheduling task was set for a 24 h time period with time resolutions of 1 h and 15 min. The performance of the proposed CP-SAT model in this study was then compared with the Monte Carlo Tree Search (MCTS)-based model (developed in our previous work). The CP-SAT was proven to perform better but has several limitations. The model response to the input parameter change has been analysed.

Hydrogen is a versatile energy vector for a plethora of applications; nevertheless its production from waste/residues is often overlooked. Gasification and subsequent conversion of the raw synthesis gas to hydrogen are an attractive alternative to produce renewable hydrogen. In this paper recent developments in R&D on waste gasification (municipal solid waste tires plastic waste) are summarised and an overview about suitable gasification processes is given. A literature survey indicated that a broad span of hydrogen relates to productivity depending on the feedstock ranging from 15 to 300 g H2/kg of feedstock. Suitable gas treatment (upgrading and separation) is also covered presenting both direct and indirect (chemical looping) concepts. Hydrogen production via gasification offers a high productivity potential. However regulations like frame conditions or subsidies are necessary to bring the technology into the market.