Romania

This manuscript contributes to understanding the role of hydrogen in different materials emphasizing polymers and composite materials to increase hydrogen storage capacity in those materials. Hydrogen storage is critical in advancing and optimizing sustainable energy solutions that are essential for improving their performance. Capillary arrays which offer increased surface area and optimized storage geometries present a promising avenue for enhancing hydrogen uptake. This work evaluates various polymers and glass for their mechanical properties and strength with 700 bar inner pressure loads within capillary tubes. A theoretical mathematical approach was employed to quantify the impact of material properties on storage capacity. Our results demonstrate that certain polymers (e.g. Zylon AS Dyneema SK99) and glass types (S-2 Glass) exhibit superior hydrogen storage potential due to their enhanced strength and low density. These findings suggest that integrating the proposed materials into capillary array systems can significantly improve hydrogen storage efficiency (15–37 wt.% and 37–40 g/L) making them viable candidates for next-generation energy storage systems. This study provides valuable insights into material selection and structural design strategies for high-capacity hydrogen storage technologies.

Hydrogen is the most abundant element on earth being a low polluting and high efficiency fuel that can be used for various applications such as power generation heating or transportation. As a reaction to climate change authorities are working for determining the most promising applications for hydrogen one of the best examples of crossborder initiative being the IPCEI (Important Project of Common European Interest) on Hydrogen under development at EU level. Given the large interest for future uses of hydrogen special safety measures have to be implemented for avoiding potential accidents. If hydrogen is stored and used under pressure accidental leaks from pressure vessels may result in fires or explosions. Worldwide researchers are investigating possible accidents generated by hydrogen leaks. Special attention is granted to the atmospheric dispersion after the release so that to avoid fires or explosions. The use of consequence modelling software within safety and risk studies has shown its’ utility worldwide. In this paper there are modelled the consequences of the accidental release and atmospheric dispersion of hydrogen from a pressure tank using state-of-the-art QRA software. The simulation methodology used in this paper uses the “leak” model for carrying out discharge calculations. This model calculates the release rate and state of the gas after its expansion to atmospheric pressure. Accidental release of hydrogen is modelled by taking into account the process and meteorological conditions and the properties of the release point. Simulation results can be used further for land use planning or may be used for establishing proper protection measures for surrounding facilities. In this work we analysed two possible accident scenarios which may occur at an imaginary hydrogen refuelling station accidents caused by the leaks of the pressure vessel with diameters of 10 and 20 mm for a pressure tank filled with hydrogen at 35 MPa / 70 MPa. Process Hazard Analysis Software Tool 8.4 has been used for assessing the effects of the scenarios and for evaluating the hazardous extent around the analysed installation. Accident simulation results have shown that the leak size has an important effect on the flammable/explosive ranges. Also the jet fire’s influence distance is strongly influenced by the pressure and actual size of the accidental release.

Deployment of innovative renewable-based energy applications are critical for reducing CO2 emissions and achieving global climate neutrality. This work evaluates the production of decarbonized green H2 based on sorption-enhanced biomass (sawdust) gasification. The calcium-based sorbent was evaluated in a looping cycle configuration as sorption material to enhance both the CO2 capture rate and the energy-efficient hydrogen production. The investigated concept is set to produce 100 MWth high purity hydrogen (>99.95% vol.) with very high decarbonization yield (>98–99%) using woody biomass as a fuel. Conventional biomass (sawdust) gasification systems with and without CO2 capture capability are also assessed for the calculation of energy and economic penalties induced by decarbonization. The results show that the decarbonized green hydrogen manufacture by sorption-enhanced biomass gasification shows attractive performances e.g. high overall energy efficiency (about 50%) reduced energy and economic penalties for almost total decarbonization (down to 8 net efficiency points) low specific carbon emissions at system level (lower than 7 kg/MWh) and negative CO2 emission for whole biomass value chain (about − 518.40 kg/MWh). However significant developments (e.g. improving reactor design and fuel/sorbent conversion yields reducing sorbent make-up etc.) are still needed to advance this innovative concept from present level to industrial sizes.

Reduction of the carbon dioxide emissions is a vital important environmental element in achieving the global climate neutrality. The integration of renewables and the Carbon Capture Utilization and Storage (CCUS) technologies is seen as an important pillar for overall decarbonization. This work presents several innovative concepts in which the biogas reforming process in integrated with pre- and post-combustion CO2 capture using membranes for green hydrogen production. The assessment evaluates the most relevant techno-economic and environmental performances for 100 MWth green hydrogen plant capacity. Several biogas reforming designs with and without CO2 capture capability were evaluated. In respect to the CO2 capture rate several pre- and postcombustion systems provided decarbonization yields between 55% up to 99%. The results show that the decarbonized membrane-based green hydrogen production shows attractive performances such as high energy efficiency (55–60%) reduced energy and cost penalties for CO2 capture (3.6–15.5 net efficiency points depending on the carbon capture rate) low specific CO2 emissions at system level (down to 2 kg/MWh green hydrogen) and overall negative carbon emission for whole biogas value chain (up to − 468 kg/MWh green hydrogen). This analysis clearly shows how the integration of renewables with CCUS technologies can deliver applications with negative CO2 emissions for climate neutrality.

This research explores the optimal operation of an offshore wave-powered hydrogen system specifically designed to supply electricity and water to a bay in Humboldt California USA and also sell it with hydrogen. The system incorporates a desalination unit to provide the island with fresh water and feed the electrolyzer to produce hydrogen. The optimization process utilizes a mixture of experts in conjunction with the Quantitative Structure-Activity Relationship (QSAR) algorithm traditionally used in drug design to achieve two main objectives: minimizing operational costs and maximizing revenue from the sale of water hydrogen and electricity. Many case studies are examined representing typical electricity demand and wave conditions during typical summer winter spring and fall days. The simulation optimization and results are carried out using MATLAB 2018 and SAM 2024 software applications. The findings demonstrate that the combination of the QSAR algorithm and quantum-inspired MoE results in higher revenue and lower costs compared to other current techniques with hydrogen sales being the primary contributor to increased income.