Transmission, Distribution & Storage

Nowadays high-pressure hydrogen storage is the most commercially used technology owing to its high hydrogen purity rapid charging/discharging of hydrogen and low-cost manufacturing. Despite numerous reviews on hydrogen storage technologies there is a relative scarcity of comprehensive examinations specifically focused on high-pressure gaseous hydrogen storage and its associated materials. This article systematically presents the manufacturing processes and materials used for a variety of high-pressure hydrogen storage containers including metal cylinders carbon fiber composite cylinders and emerging glass material-based hydrogen storage containers. Furthermore it introduces the relevant principles and theoretical studies showcasing their advantages and disadvantages compared to conventional high-pressure hydrogen storage containers. Finally this article provides an outlook on the future development of high-pressure hydrogen storage containers.

Underground hydrogen storage (UHS) in aquifers salt caverns and depleted hydrocarbon reservoirs allows for the storage of larger volumes of H2 compared to surface storage in vessels. In this work we investigate the impact of aquifer-related mechanisms and parameters on the performance of UHS in an associated North Sea aquifer using 3D numerical compositional simulations. Simulation results revealed that the aquifer's permeability heterogeneity has a significant impact on the H2 recovery efficiency where a more homogenous rock would lead to improved H2 productivity. The inclusion of relative permeability hysteresis resulted in a drop in the H2 injectivity and recovery due to H2 discontinuity inside the aquifer which leads to residual H2 during the withdrawal periods. In contrast the effects of hydrogen solubility and hydrogen diffusion were negligible when studied each in isolation from other factors. Hence it is essential to properly account for hysteresis and heterogeneity when evaluating UHS in aquifers.

As global economies seek to transition to low-carbon energy systems to achieve net zero targets hydrogen has potential to play a key role to decarbonise sectors that are unsuited to electrification or where long-term energy storage is required. Hydrogen can also assist in enabling decentralized renewable power generation to satisfy higher electricity demand to match the scale-up of electrified technologies. In this context suitable transport storage and distribution networks will be essential to connect hydrogen generation and utilisation sites. This paper presents a techno-economic impact evaluation of international marine hydrogen transportation between Canada and the Netherlands comparing liquid hydrogen ammonia and a dibenzyl toluene liquid organic hydrogen carrier (LOHC) as potential transport vectors. Economic costs energy consumption and losses in each phase of the transportation system were analysed for each vector. Based on the devised scenarios our model suggests levelised costs of hydrogen of 6.35–9.49 $2022/kgH2 and pathway efficiencies of 55.6–71.9%. While liquid hydrogen was identified as the most cost-competitive carrier sensitivity analysis revealed a merit order for system optimisation strategies based upon which LOHC could outperform both liquid hydrogen and ammonia in the future.

Pipelines represent the most economical and efficient means for transporting hydrogen in large volumes across vast distances contributing to accelerated realization of hydrogen economy. Nowadays the development of hydrogen pipeline projects including repurposing existing pipelines for hydrogen service has become a global interest especially in those major energy-producing and energy-consuming countries. However steel pipelines are susceptible to hydrogen embrittlement (HE) in high-pressure hydrogen gas environments potentially leading to pipeline failures. In this review we establish a comprehensive knowledge base for comprehending testing and evaluating the gaseous HE in pipelines by a thorough examination of relevant research work. In addition to an overview of some major hydrogen pipeline projects in the world the article consists of four integral parts essential to gaseous HE studies namely methods for exposure of steels to high-pressure hydrogen gas; measurements of the quantity of H atoms inside the steels; stress-strain behavior of pipeline steels under highpressure hydrogen gas exposure; and fracture and fatigue testing of pre-cracked steels within gaseous environments. Further research into gaseous HE in pipelines focuses on developing standardized quantitative and consistent methods to assess and define the susceptibility of pipelines to gaseous HE.

Ammonia is a promising hydrogen carrier for enabling the efficient transport of hydrogen as observed by the many hydrogen transport projects using ammonia. For the clean energy future understanding environmental impacts of the transport system is important. This study conducts life cycle assessment (LCA) for the marine transport of renewable hydrogen using ammonia as the hydrogen carrier. The LCA considered renewable hydrogen produced from four systems; wind-powered electrolysis gasification of forest residue anaerobic digestion of food waste and landfill gas reforming; followed by Haber-Bosch ammonia synthesis using the renewable hydrogen and nitrogen produced from air separation. The ammonia was then transported 11000 km by sea to a destination facility where it was decomposed using either Ru or Ni catalysts to obtain hydrogen. Among the four hydrogen transport systems operated with renewable energy electrolysis-hydrogen system presented the highest global warming impact of 3.31 kg CO2 eq/kg H2 due to electricity use for the electrolysis whereas simpler processes based on a landfill gas system led to the lowest impact of 2.27 kg CO2 eq/kg H2. Process energy consumption was the major contributor to global warming impact with 27%–49.2% of contri bution. The consumption of metals and energy during wind turbine construction resulted in the most significant impact in six out of 12 midpoint impact categories for the electrolysis-hydrogen system which also led to the highest endpoint impacts. The endpoint impacts of the four systems were in the order of electrolysis > food waste > forest residue > landfill gas (from high to low) for both endpoint human health and ecosystems impacts. Ammonia decomposition using Ru catalysts exhibited slightly lower global warming impact than Ni catalysts while final purification of hydrogen by vanadium membrane presented 4.8% lower impacts than the purification by pressure swing adsorption. Large-scale hydrogen supply chains can be achieved by technological improve ment and support of policies and financial schemes.

Electrifying ammonia production using renewable energy (RE) and water electrolysis is a critical step in the worldwide transition from fossil fuels to alternative energy sources. However the common requirement that the ammonia reactor operate at a steady production level harms the system’s economic feasibility due to the large hydrogen and battery storage required to overcome RE variability. In this study we examine the sensitivity of the plant storage capacity requirement to the flexibility of the ammonia reactor. We examine two aspects of ammonia reactor flexibility: ramping rate flexibility and the range of operation (turndown flexibility). We develop a storage dispatch and ammonia reactor scheduling optimization which computes the minimum storage requirement given a RE generation profile and set of reactor flexibility parameters. We optimize across a sweep of flexibility parameters for two locations in the United States. We find that turndown flexibility is the most important while ramping flexibility has little effect on the overall storage requirement. Further we see that seasonal variability in the RE generation profile is the primary driver of high storage capacity requirement. We find that with a turndown flexibility of 60% of the ammonia plants rated capacity which is understood to be achievable with existing ammonia reactor technology the storage capacity was reduced by 84 % in one of the locations we examined which resulted in a 22% decrease in the levelized cost of ammonia with pipe-based hydrogen storage.

To inject green hydrogen (H2) into the existing natural gas (NG) infrastructure is one way to decarbonize the European energy system. However asset readiness is necessary to be successful. Preliminary analysis and experimental results about the compatibility of hydrogen and natural gas mixtures (H2NG) with the actual gas grids make the scientific community confident about the feasibility. Nevertheless specific technical questions need more research. A significant topic of debate is the impact of H2NG mixtures on the performance of state-ofthe-art fiscal measuring devices which are essential for accurate billing. Identifying and addressing any potential degradation in their metrological performance due to H2NG is critical for decision-making. However the literature lacks data about the gas meters’ technologies currently installed in the NG grids such as a comprehensive overview of their readiness at different concentrations while data are fragmented among different sources. This paper addresses these gaps by analyzing the main characteristics and categorizing more than 20000 gas meters installed in THOTH2 project partners’ grids and by summarizing the performance of traditional technologies with H2NG mixtures and pure H2 based on literature review operators experience and manufacturers knowledge. Based on these insights recommendations are given to stakeholders on overcoming the identified barriers to facilitate a smooth transition.

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 emerging as a promising future energy medium in a wide range of industries. For mobile applica tions it is commonly stored in a gaseous state within high-pressure composite overwrapped pressure vessels (COPVs). The current state of the art pressure vessel technology known as Type V eliminates the internal polymer gas barrier used in Type IV vessels and instead relies on carbon fibre laminate to provide structural properties and prevent gas leakage. Achieving this functionality at high pressure poses several engineering challenges that have thus far prohibited commercial application. Additionally the traditional manufacturing process for COPVs filament winding has several constraints that limit the design space. Automated fibre placement (AFP) a highly flexible robotic composites manufacturing technique has the potential to replace filament winding for composite pressure vessel manufacturing and provide pathways for further vessel optimi sation. A combination of both AFP and Type V technology could provide an avenue for a new generation of highperformance composite pressure vessels. This critical review presents key work on industry-standard Type IV vessels alongside the current state of Type V CPV technology including manufacturing developments challenges cost relevance to commercial standards and future fabrication solutions using AFP. Additionally a novel Type V CPV design concept for a two-piece AFP produced vessel is presented.

Hydrogen tanks (HT) with different connection modes are an integral part of the shipborne hydrogen fuel cell system. To ensure the safe and reliable operation of the shipborne multi-tank cascade system this study innovatively develops 3D models of four different connection modes for the shipborne multi-tank cascade system namely Type-22 Type-211 Type-121 and Type-112. Through computational fluid dynamics (CFD) numerical simulation the variations in parameters of different multi-tank cascade systems during the hydrogen storage process are analyzed. The results indicate that the maximum temperature of Type-112 is 271.107K which is 2.220% 4.779% and 3.993% lower than that of Type-22 Type-211 and Type-121 respectively and thus the optimal parameters such as the initial temperature in the tank and pre-cooling temperature are derived. Type-112's maximum temperature is reduced by 14.02% and 16.66% compared to systems connected solely in series or in parallel. The study identifies the optimal structure and reasonable hydrogen storage parameters effectively reducing heat generation during the refueling process while optimizing space utilization thereby strongly ensuring the stability of hydrogen storage and opening up new avenues for addressing related hydrogen storage issues in the future.