Publications

This study identifies limitations and research and development (R&D) gaps at both the component and system levels for hydrogen energy systems (HESs) and specifies how these limitations impact HES adoption within the electric power system (EPS) decarbonization roadmap. To trace these limitations and potential solutions an analytical review is conducted in electrification and integration of HESs renewable energy sources (RESs) and multi-carrier energy systems (MCESs) in sequence. The study also innovatively categorizes HES integration challenges into component and system levels. At the component level technological aspects of hydrogen generation storage transportation and refueling are explored. At the system level HES coordination hydrogen market frameworks and adoption challenges are evaluated. Findings highlight R&D gaps including misalignment between HES operational targets and techno-economic development integration insufficiency model deficiencies and challenges in operational complexity. This study provides insights for sustainable energy integration by supporting the transition to a decarbonized energy system.

For fast-tracking climate change response green hydrogen is key for achieving greenhouse gas neutral energy systems. Especially Sub-Saharan Africa can benefit from it enabling an increased access to clean energy through utilizing its beneficial conditions for renewable energies. However developing green hydrogen strategies for Sub-Saharan Africa requires highly detailed and consistent information ranging from technical environmental economic and social dimensions which is currently lacking in literature. Therefore this paper provides a comprehensive novel approach embedding the required range of disciplines to analyze green hydrogen costpotentials in Sub-Saharan Africa. This approach stretches from a dedicated land eligibility based on local preferences a location specific renewable energy simulation locally derived sustainable groundwater limitations under climate change an optimization of local hydrogen energy systems and a socio-economic indicator-based impact analysis. The capability of the approach is shown for case study regions in Sub-Saharan Africa highlighting the need for a unified interdisciplinary approach.

Hydrogen is viewed as a potential energy solution for the 21st century with capabilities to tackle issues relating to environmental emissions sustainability energy shortages and security. Even though there are potential benefits of renewable hydrogen towards transitioning to net-zero emissions there is a limited study on the current use ongoing development and future directions of renewable hydrogen in Australia. Thus this study conducts a systematic review of studies for exploring Australia’s renewable hydrogen energy transition current trends strategies developments and future directions. By using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines earlier studies from 2005 to 2024 from two major databases such as ProQuest and Web of Science are gathered and analyzed. The study highlights significant issues relating to hydrogen energy technologies and opportunities/challenges in production storage distribution utilization and environmental impacts. The study found that Australia’s ambition for a strong hydrogen economy is made apparent with its clear strategic actions to develop a clean technology-based hydrogen production storage and distribution system. This study provides several practical insights on Australia’s hydrogen energy transition hydrogen energy technologies investments and innovation as well as strategies/recommendations for achieving a more environment friendly secure affordable and sustainable energy future.

The hydrogen compatibility of two X65 pipeline steels for transport of hydrogen gas is investigated through microstructural characterization hydrogen permeation measurements and fracture mechanical testing. The investigated materials are a quenched and tempered pipeline steel with a fine-grained homogeneously distributed ferrite-bainite microstructure and hot rolled pipeline steel with a ferrite-pearlite banded microstructure. All tests are performed both under electrochemical and gaseous hydrogen charging conditions. A correlation between electrochemical hydrogen charging and gaseous charging is determined. The results point to inherent differences in the interaction between hydrogen and the two material microstructures. Further research is needed to unveil the influence of material microstructure on hydrogen embrittlement.

The UK government plans to phase out pure diesel trains by 2040 and fully decarbonize railways by 2050. Hydrogen fuel cell (HFC) trains electrified trains using pantographs (Electrified Trains) and battery electric multiple unit (BEMU) trains are considered the main solutions for decarbonizing railways. However the range of these decarbonization options’ line upgrade cost advantages is unclear. This paper analyzes the upgrade costs of three types of trains on different lines by constructing a cost model and using particle swarm optimization (PSO) including operating costs and fixed investment costs. For the case of decarbonization of the London St. Pancras to Leicester line the electrified train option is more cost-effective than the other two options under the condition that the service period is 30 years. Then the traffic density range in which three new energy trains have cost advantages on different line lengths is calculated. For route distances under 100 km and with a traffic density of less than 52 trips/day BEMU trains have the lowest average cost while electrified trains are the most costeffective in other ranges. For route distances over 100 km the average cost of HFC trains is lower than that of electrified trains at traffic densities below about 45 trips/day. In addition if hydrogen prices fall by 26 % the cost advantage range of HFC trains will increase to 70 trips per day. For route distances under 100 km BEMU trains still maintain their advantages in terms of lower traffic density.

Hydrogen globally recognized as the most efficient and clean energy carrier holds the potential to transform future energy systems through its use as a fuel and chemical resource. Although progress has been made in reversible hydrogen adsorption and release challenges in storage continue to impede widespread adoption. This review explores recent advancements in hydrogen storage materials and synthesis methods emphasizing the role of nanotechnology and innovative synthesis techniques in enhancing storage performance and addressing these challenges to drive progress in the field. The review provides a comprehensive overview of various material classes including metal hydrides complex hydrides carbon materials metal-organic frameworks (MOFs) and porous materials. Over 60 % of reviewed studies focused on metal hydrides and alloys for hydrogen storage. Additionally the impact of nanotechnology on storage performance and the importance of optimizing synthesis parameters to tailor material properties for specific applications are summarized. Various synthesis methods are evaluated with a special emphasis on the role of nanotechnology in improving storage performance. Mechanical milling emerges as a commonly used and cost-effective method for fabricating intermetallic hydrides capable of adjusting hydrogen storage properties. The review also explores hydrogen storage tank embrittlement mechanisms particularly subcritical crack growth and examines the advantages and limitations of different materials for various applications supported by case studies showcasing real-world implementations. The challenges underscore current limitations in hydrogen storage materials highlighting the need for improved storage capacity and kinetics. The review also explores prospects for developing materials with enhanced performance and safety providing a roadmap for ongoing advancements in the field. Key findings and directions for future research in hydrogen storage materials emphasize their critical role in shaping future energy systems.

With renewable energy sources projected to become the dominant source of electricity hydrogen has emerged as a crucial energy carrier to mitigate their intermittency issues. Water electrolysis is the most developed alternative to generate green hydrogen so far. However in the past two decades steam electrolysis has attracted increasing interest and aims to become a key player in the portfolio of electrolytic hydrogen. In practice steam electrolysis follows two distinct operational approaches: Solid Oxide Electrolysis Cell (SOEC) and Proton Exchange Membrane (PEM) at high temperature. For both technologies this work analyses critical cell components outlining material characteristics and degradation issues. The influence of operational conditions on the performance and cell durability of both technologies is thoroughly reviewed. The analytical comparison of the two electrolysis alternatives underscores their distinct advantages and drawbacks highlighting their niche of applications: SOECs thrive in high temperature industries like steel production and nuclear power plants whereas PEM steam electrolysis suits lower temperature applications such as textile and paper. Being PEM steam electrolysis less explored this work ends up by suggesting research lines in the domain of i) cell components (membranes catalysts and gas diffusion layers) to optimize and scale the technology ii) integration strategies with renewable energies and iii) use of seawater as feedstock for green hydrogen production.

This paper investigated the opportunities and challenges of integrating ports into hydrogen (H2 ) supply chains in the context of Australia and Japan because they are leading countries in the field and are potential leaders in the upcoming large-scale H2 trade. Qualitative interviews were conducted in the two countries to identify opportunities for H2 ports necessary infrastructure and facilities key factors for operations and challenges associated with the ports’ development followed by an online survey investigating the readiness levels of H2 export and import ports. The findings reveal that there are significant opportunities for both countries’ H2 ports and their respective regions which encompass business transition processes and decarbonisation. However the ports face challenges in areas including infrastructure training standards and social licence and the sufficiency and readiness levels of port infrastructure and other critical factors are low. Recommendations were proposed to address the challenges and barriers encountered by H2 ports. To optimise logistics operations within H2 ports and facilitate effective integration of H2 applications this paper developed a user-oriented working process framework to provide guidance to ports seeking to engage in the H2 economy. Its findings and recommendations contribute to filling the existing knowledge gap pertaining to H2 ports.

The production of hydrogen from photovoltaics (PV) has gained attention due to its potential as an energy vector. In this context there are two basic configurations for electrically coupling PV to hydrogen electrolyzers: direct and indirect. The direct configuration operates variably based on meteorological conditions but has simplicity as an advantage. The indirect configuration involves a power stage (PS) with a maximum power point tracker and a DC-DC converter maintaining an optimal power transfer from PV to electrolyzers but incurs losses at the PS. The direct configuration avoids these losses but requires a specific design of the PV generator to achieve high electrical transfer. The comparative analysis of hydrogen production between these two approaches indicates that the indirect paradigm yields a 37.5% higher hydrogen output throughout a typical meteorological year compared to the optimized direct configuration. This increase enhances the overall sunlight-to-hydrogen efficiency elevating it from 5.0% in the direct case to 6.9% in the indirect one. Furthermore the direct setup sensitive to PV power fluctuations suffers an 18% reduction in hydrogen production with just a 5% reduction in photogenerated power. Under optimal performance the direct coupling produces less hydrogen unless the DCDC converter efficiency drops 17% below commercial standards.

As the main contributor of carbon emissions the low-carbon transition of the industrial sector is important for achieving the goal of carbon dioxide peaking. Hydrogen-enabled industrial energy systems (HIESs) are a promising way to achieve the low-carbon transition of industrial energy systems since the hydrogen can be well coordinated with renewable energy sources and satisfy the high and continuous industrial energy demand. In this paper the long-term capacity expansion planning problem of the HIES is formulated from the perspective of industrial parks and the targets of carbon dioxide peaking and the gradual decommissioning of existing equipment are considered as constraints. The results show that the targets of carbon dioxide peaking before different years or with different emission reduction targets can be achieved through the developed method while the economic performance is ensured to some extent. Meanwhile the overall cost of the strategy based on purchasing emission allowance is three times more than the cost of the strategy obtained by the developed method while the emissions of the two strategies are same. In addition long-term carbon reduction policies and optimistic expectations for new energy technologies will help industrial parks build more new energy equipment for clean transformation.

This paper deals with the optimal scheduling of the resources of a renewable energy community whose coordination is aimed at providing flexibility services to the electrical distribution network. The available resources are renewable generation units battery energy storage systems dispatchable loads and power-to-hydrogen systems. The main purposes behind the proposed strategy are enhancement of self-consumption and hydrogen production from local resources and the maximization of the economic benefits derived from both the selling of hydrogen and the subsidies given to the community for the shared energy. The proposed approach is formulated as an economic problem accounting for the perspectives of both community members and the distribution system operator. In more detail a mixed-integer constrained non-linear optimization problem is formulated. Technical constraints related to the resources and the power flows in the electrical grid are considered. Numerical applications allow for verifying the effectiveness of the procedure. The results show that it is possible to increase self-consumption and the production of green hydrogen while providing flexibility services through the exploitation of community resources in terms of active and reactive power support. More specifically the application of the proposed strategy to different case studies showed that daily revenues of up to EUR 1000 for each MW of renewable energy generation installed can be obtained. This value includes the benefit obtained thanks to the provision of flexibility services which contribute about 58% of the total.

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.

The forthcoming implementation of national policies towards hydrogen blending into the natural gas grid will affect the technical and economic parameters that must be taken into account in the design of building heating systems. This study evaluates the implications of using hydrogenenriched natural gas (H2NG) blends in condensing boilers and Gas Adsorption Heat Pumps (GAHPs) in a residential building in Rome Italy. The analysis considers several parameters including nonrenewable primary energy consumption CO2 emissions Levelized Cost of Heat (LCOH) and Carbon Abatement Cost (CAC). The results show that a 30% hydrogen blend achieves a primary energy consumption reduction of 12.05% and 11.19% in boilers and GAHPs respectively. The presence of hydrogen in the mixture exerts a more pronounced influence on the reduction in fossil primary energy and CO2 emissions in condensing boilers as it enhances combustion efficiency. The GAHP system turns out to be more cost-effective due to its higher efficiency. At current hydrogen costs the LCOH of both technologies increases as the volume fraction of hydrogen increases. The forthcoming cost reduction in hydrogen will reduce the LCOH and the decarbonization cost for both technologies. At low hydrogen prices the CAC for boilers is lower than for GAHPs; therefore replacing boilers with other gas technologies rather than electric heat pumps increases the risk of creating stranded assets. In conclusion blending hydrogen into the gas grid can be a useful policy to reduce emissions from the overall natural gas consumption during the process of end-use electrification while stimulating the development of a hydrogen economy.

Given China’s ambition to realize carbon peak by 2030 and carbon neutralization by 2060 hydrogen is gradually becoming the pivotal energy source for the needs of energy structure optimization and energy system transformation. Thus hydrogen combined with renewable energy has received more and more attention. Nowadays power-to-hydrogen power-to-methanol and power-to-ammonia are regarded as the most promising three hydrogen-driven power-to-X technologies due to the many commercial or demonstration projects in China. In this paper these three hydrogen-driven power-to-X technologies and their application status in China are introduced and discussed. First a general introduction of hydrogen energy policies in China is summarized and then the basic principles technical characteristics trends and challenges of the three hydrogen-driven power-to-X technologies are reviewed. Finally several typical commercial or demonstration projects are selected and discussed in detail to illustrate the development of the power-to-X technologies in China.