Italy

As the transport of gaseous hydrogen and its use as a low carbon-footprint energy vector become increasingly likely scenarios both the scientific literature and technical standards addressing the compatibility of pipeline steels with high-pressure hydrogen environments are rapidly expanding. This work presents a detailed review of the most relevant hydrogen embrittlement testing methodologies proposed in standards and the academic literature. The focus is placed on testing approaches that support design-oriented assessments rather than simple alloy qualification for hydrogen service. Particular attention is given to tensile tests (conducted on smooth and notched specimens) as well as to J-integral and fatigue tests performed following the fracture mechanics’ approach. The influences of hydrogen partial pressure and deformation rate are critically examined as these parameters are essential for ensuring meaningful comparisons across different studies.

Hydrogen Valley represents localised ecosystems that enable the integrated production storage distribution and utilisation of hydrogen to support the decarbonisation of the energy system. However planning such integrated systems necessitates a detailed evaluation of their interconnections with variable renewable generation sector coupling and system flexibility. The novelty of this work lies in addressing a critical gap in system-level modelling for Hydrogen Valleys by introducing an optimization-based framework to determine their optimal configuration. This study focuses on the scenario-based multiobjective design of local hydrogen energy systems considering renewable integration infrastructure deployment and sector coupling. We developed and simulated three scenarios based on varying hydrogen pathways and penetration levels using the EnergyPLAN model implemented through a custom MATLAB Toolbox. Several decision variables such as renewable energy capacity electrolyser size and hydrogen storage were optimised to minimise CO₂ emissions total annual system cost and critical excess electricity production simultaneously. The findings show that Hydrogen Valley deployment can reduce CO₂ emissions by up to 30 % triple renewable penetration in the primary energy supply and lower the levelized cost of hydrogen from 7.6 €/kg to 5.6 €/kg despite a moderate increase in the total cost of the system. The approach highlights the potential of sector coupling and Power-to-X technologies in enhancing system flexibility and supporting green hydrogen integration. The outcome of our research offers valuable insights for policymakers and planners seeking to align local hydrogen strategies with broader decarbonisation targets and regulatory frameworks.

In the context of the evolving energy landscape the need to harness renewable energy sources (RESs) has become increasingly imperative. Within this framework hydrogen emerges as a promising energy storage vector offering a viable solution to the flexibility challenges caused by the inherent variability of RESs. This work investigates the feasibility of integrating a hydrogen-based energy storage system within an energy community in Barcelona using surplus electricity from photovoltaic (PV) panels. A power-to-power configuration is modelled through a comprehensive methodology that determines optimal component sizing based on high-resolution real-world data. This analysis explores how different operational strategies influence the system’s cost-effectiveness. The methodology is thus intended to assist in the early-stage decision-making process offering a flexible approach that can be adapted to various market conditions and operational scenarios. The results show that under the current conditions the combination of PV generation energy storage and low-cost grid electricity purchases yield the most favourable outcomes. However in a long-term perspective considering projected cost reductions for hydrogen technologies strategies including energy sales back to the grid become more profitable. This case study offers a practical example of balancing engineering and economic considerations providing replicable insights for designing hydrogen storage systems in similar energy communities.

Hydrogen-based technologies prominently fuel cells are emerging as strategic solutions for decarbonization. They offer an efficient and clean alternative to fossil fuels for electricity generation making a tangible contribution to the European Green Deal climate objectives. The primary issue is the production and transportation of hydrogen. An on-site hydrogen production system that includes CO2 capture could be a viable solution. The proposed power system integrates an internal combustion engine (ICE) with a steam methane reformer (SMR) equipped with a CO2 capture and energy storage system to produce “blue hydrogen”. The hydrogen fuels a high-temperature polymer electrolyte membrane (HTPEM) fuel cell. A battery pack incorporated into the system manages rapid fluctuations in electrical load ensuring stability and continuity of supply and enabling the fuel cell to operate at a fixed point under nominal conditions. This hybrid system utilizes natural gas as its primary source reducing climate-altering emissions and representing an efficient and sustainable solution. The simulation was conducted in two distinct environments: Thermoflex code for the integration of the engine reformer and CO2 capture system; and Matlab/Simulink for fuel cell and battery pack sizing and dynamic system behavior analysis in response to user-demanded load variations with particular attention to energy flow management within the simulated electrical grid. The main results show an overall efficiency of the power system of 39.9% with a 33.5% reduction in CO2 emissions compared to traditional systems based solely on internal combustion engines.

This study explores the design and feasibility of a novel fuel cell-powered wind farm for residential electricity hydrogen/oxygen production and cooling/heating via a compression chiller. Wind turbine energy powers Proton Exchange Membrane (PEM) electrolyzers and a compression chiller unit. The proposed system was modeled using EES thermodynamic software and its economic viability was assessed. A case study across seven Italian regions with varying wind potentials evaluated the system’s feasibility in diverse weather conditions. Multi-objective optimization using Response Surface Methodology (RSM) determined the number of wind turbines as optimum number of electrolyzers & fuel cell units. Optimization results indicated that 37 wind turbines 1 fuel cell unit and 2 electrolyzer units yielded an exergy efficiency of 27.98 % and a cost rate of 619.9 $/h. TOPSIS analysis suggested 32 wind turbines 2 electrolyzers and 2 reverse osmosis units as an alternative configuration. Further twelve different scenarios were examined to enhance the distribution of wind farmgenerated electricity among the grid electrolyzers and reverse osmosis systems. revealing that directing 25 % to reverse osmosis 20 % to electrolyzers and 55 % to grid sales was optimal. Performance analysis across seven Italian cities (Turin Bologna Florence Palermo Genoa Milan and Rome) identified Genoa Palermo and Bologna as the most suitable locations due to favorable wind conditions. Implementing the system in Genoa the optimal site could produce 28435 MWh of electricity annually prevent 5801 tons of CO2 emissions (equivalent to 139218 $). Moreover selling this clean electricity to the grid could meet the annual clean electricity needs of approximately 5770 people in Italy

The paper approaches a computational evaluation of the 100% hydrogen fueled DLR micro-Gas Turbine (mGT) burner F400S.3 through high-fidelity Large Eddy Simulations (LES). Sensitivity analyses on the thermal boundary conditions of the burner walls and the turbulent combustion model were conducted. The experimental OH*-Chemiluminescence distribution was compared with numerical results obtained using the Partially Stirred Reactor (PaSR) and the Extended Flamelet Generated Manifold (ExtFGM) combustion models. The results showed good agreement regarding the flame shape and reactivity prediction when non-adiabatic thermal boundary conditions were applied at the burner walls and the PaSR model was implemented. On the contrary the ExtFGM model exhibited underprediction in flame length and flame lift-off overestimating flame reactivity. Finally after selecting the combustion model that best retrieved the experimental data a pressurized LES was performed on the combustor domain to evaluate its performance under real operating conditions for mGT.

Hydrogen is increasingly recognized as a key energy vector for achieving deep decarbonization across urban and industrial sectors. Supporting global efforts to reduce greenhouse gas (GHG) emissions and achieve the Sustainable Development Goals (SDGs) it is essential to understand the multi-sectoral role of the hydrogen value chain spanning production storage and end-use applications with particular emphasis on smart city systems and industrial processes. Green hydrogen production technologies including alkaline water electrolysis (AWE) proton exchange membrane (PEM) electrolysis anion exchange membrane (AEM) electrolysis and solid oxide electrolysis cells (SOECs) are evaluated in terms of efficiency scalability and integration potential. Storage pathways are examined across physical storage (compressed gas cryo-compressed and liquid hydrogen) material-based storage (solid-state absorption in metal hydrides and chemical carriers such as LOHCs and ammonia) and geological storage (salt caverns depleted gas reservoirs and deep saline aquifers) highlighting their suitability for urban and industrial contexts. In the smart city domain hydrogen is analyzed as an enabler of zero-emission transportation low-carbon residential and commercial heating and renewable-integrated smart grids with long-duration storage capabilities. System-level studies demonstrate that coordinated integration of these applications can deliver higher overall energy efficiency deeper reductions in life-cycle GHG emissions and improved resilience of urban energy systems compared with sector-specific approaches. Policy frameworks safety standards and digitalization strategies are reviewed to illustrate how hydrogen infrastructure can be embedded into interconnected urban energy systems. Furthermore industrial applications focus on hydrogen’s potential to decarbonize energy-intensive processes and enable sector coupling between electricity heat and manufacturing. The environmental implications of hydrogen deployment are also considered including resource efficiency life-cycle emissions and ecosystem impacts. In contrast to reviews addressing isolated aspects of hydrogen technologies this study synthesizes technological infrastructural and policy dimensions integrating insights from over 400 studies to highlight the multifaceted role of hydrogen in sustainable urban development and industrial decarbonization and the added benefits achievable through coordinated cross-sector deployment strategies.

The urgent need to mitigate climate change and reduce greenhouse gas emissions has accelerated the search for sustainable and scalable energy carriers. Among the different alternatives ammonia stands out as a promising carbon-free fuel thanks to its high energy density efficient storage and compatibility with existing infrastructure. Moreover it can be produced through sustainable green processes. However its application in internal combustion engines is limited by several challenges including low reactivity narrow flammability limits and high ignition energy. These factors can compromise combustion efficiency and contribute to increased unburned ammonia emissions. To address these limitations hydrogen has emerged as a complementary fuel in dual-fuel configurations with ammonia. Hydrogen’s high reactivity enhances flame stability ignition characteristics and combustion efficiency while reducing emissions of unburned ammonia. This review examines the current status of dual-fuel ammonia and hydrogen combustion strategies in internal combustion engines and summarizes the experimental results. It highlights the potential of dual-fuel systems to optimize engine performance and minimize emissions. It identifies key challenges knowledge gaps and future research directions to support the development and widespread adoption of ammonia–hydrogen dual-fuel technologies.

The effects of climate change and reliance on fossil fuels in the Alps highlight the need for energy sufficiency improved efficiency and renewable energy deployment to support decarbonization goals. Hydrogen has gained attention as a versatile zero-emission energy carrier with the potential to drive cleaner energy solutions and sustainable tourism in Alpine regions. This study shares findings from a hydrogen survey conducted within the Interreg Alpine Space AMETHyST project which included questionnaires and roundtable discussions across Alpine territories. The survey explored hydrogen’s role in decarbonizing the Alps gathering insights from local stakeholders about their knowledge expertise needs and targets for hydrogen solutions. It also mapped existing hydrogen initiatives. Results revealed strong interest in hydrogen implementation with many territories eager to launch projects. However high investment and operational costs along with associated risks are key barriers. The absence of clear local hydrogen strategies and of a comprehensive regulatory framework also poses significant challenges. Incentivization schemes could facilitate initiatives and foster local hydrogen economies. The most promising application areas for hydrogen in the Alps are private and public mobility sectors. The residential sector particularly in tourist accommodations also presents potential. Regardless of specific uses developing renewable energy capacity and infrastructure is essential to create green hydrogen ecosystems that can store excess renewable energy from intermittent sources for later use.

This paper provides a comprehensive review of novel aviation technologies analyzing the advancements and challenges associated with the transition to sustainable air transport. The study explores three key pillars: unconventional aerodynamic configurations novel propulsion systems and advanced materials. Unconventional airframe architectures such as box-wing blended-wing-body and truss-braced wings demonstrate potential for improved aerostructural efficiency and reduced fuel consumption compared to traditional tube-and-wing designs. Aeropropulsive innovations as distributed propulsion boundary layer ingestion and advanced turbofan configurations are also promising in this regard. Significant progress in propulsion technologies including hybrid-electric hydrogen and extensive use of sustainable aviation fuels (SAF) plays a pivotal role in reducing air transport greenhouse gas emissions. However energy storage limitations and infrastructure constraints remain critical challenges and hence in the near future SAF could represent the most feasible solution. The introduction of advanced lightweight materials could further enhance aircraft overall performance. The results presented and discussed in this paper show that there is no a unique solution to the problem of the sustainability of air transport but a combination of all the novel technologies is necessary to achieve the ambitious environmental goals for the air transport of the future.