Publications

Nowadays several technologies based on powertrain electrification and the exploitation of hydrogen represent valuable options for decarbonizing the on-road public transport sector. The considered alternatives should exhibit an effective benchmark between CO2 reduction potential and production/operational costs. Conducting a comprehensive Total Cost of Ownership (TCO) analysis coupled with a thorough Life Cycle Assessment (LCA) is therefore crucial in shaping the future for cleaner urban mobility. From this perspective this study compares different powertrain configurations for a 12 m urban bus: a conventional diesel Internal Combustion Engine Vehicle (ICEV) a series hybrid diesel two hydrogen-based series hybrid vehicles: a Hydrogen Hybrid Electric Vehicle featuring an H2-ICE (H2-HEV) or a Fuel Cell Electric Vehicle (FCEV) and a Battery Electric Vehicle (BEV). Moreover a sensitivity analysis has been conducted on the carbon footprint for power generation considering also the marginal electricity mix. In addition prospective LCA and TCO elements are introduced by addressing future technological projections for the 2030 horizon. The research reveals that as of today the BEV and hydrogen-fueled vehicles have comparable environmental impacts when the marginal electricity mix is considered. The techno-economic analysis indicates that under current conditions FCEVs and H2-HEVs are not cost-effective for CO₂ reduction unless powered by renewable energy sources. However considering future technological advancements and market evolution FCEVs offer the most promising balance between economic and environmental benefits particularly if hydrogen prices reach €4 per kilogram. If hydrogen-powered vehicles remain a niche market BEVs will be the most viable option for decarbonizing the transport sector in most European countries.

This study presents the development and implementation of an AI-driven control system for dynamic regulation of hydrogen blending in natural gas networks. Leveraging supervised machine learning techniques a Random Forest Classifier was trained to accurately identify the origin of gas blends based on compositional fingerprints achieving rapid inference suitable for real-time applications. Concurrently a Random Forest Regression model was developed to estimate the optimal hydrogen flow rate required to meet a user-defined higher calorific value target demonstrating exceptional predictive accuracy with a mean absolute error of 0.0091 Nm3 and a coefficient of determination (R2 ) of 0.9992 on test data. The integrated system deployed via a Streamlit-based graphical interface provides continuous real-time adjustments of gas composition alongside detailed physicochemical property estimation and emission metrics. Validation through comparative analysis of predicted versus actual hydrogen flow rates confirms the robustness and generalizability of the approach under both simulated and operational conditions. The proposed framework enhances operational transparency and economic efficiency by enabling adaptive blending control and automatic source identification thereby facilitating optimized fuel quality management and compliance with industrial standards. This work contributes to advancing smart combustion technologies and supports the sustainable integration of renewable hydrogen in existing gas infrastructures.

Methane steam reforming is the most widely adopted hydrogen production technology. To address the challenges associated with the large radial thermal resistance and low mass transfer rates inherent in the tubular packed bed reactors during the MSR process this study proposes a structural design optimization that integrates annular metal foam gas channels along the inner wall of the reforming tubes. Utilizing multi-physics simulation methods and taking the conventional tubular reactor as a baseline a comparative analysis was performed on physical parameters that characterize flow behavior heat transfer and reaction in the reforming process. The integration of the annular channels induces a radially non-uniform distribution of flow resistance in the tubes. Since the metal foam exhibits lower resistance the fluid preferentially flows through the annular channels leading to a diversion effect that enhances both convective heat transfer and mass transfer. The diversion effect redirects the central flow toward the near-wall region where the higher reactant concentration promotes the reaction. Additionally the higher thermal conductivity of the metal foam strengthens radial heat transfer further accelerating the reaction. The effects of operating parameters on performance were also investigated. While a higher inlet velocity tends to hinder the reaction in tubes integrated with annular channels it enhances the diversion effect and convective heat transfer. This offsets the adverse impact maintaining high methane conversion with lower pressure drop and thermal resistance than the conventional tubular reactor does.

Hydrogen fuel cells are gaining attention as an eco-friendly propulsion system for ships but the structural safety of storage tanks which store hydrogen at high pressure and supply it to the fuel cell is a critical concern. Marine liquid hydrogen storage tanks typically designed as rotationally symmetric structures face challenges when subjected to asymmetric wave-induced sloshing loads that break geometric symmetry and induce localized stress concentrations. This study conducted a fluid–structure interaction (FSI) analysis of a rotationally symmetric liquid hydrogen storage tank for marine applications to evaluate the impact of asymmetric liquid sloshing induced by wave loads on the tank structure and propose symmetry-guided structural improvement measures to ensure fatigue life. Sensitivity analysis using the finite difference method (FDM) revealed the asymmetric influences of design variables on stress distribution: increasing the thickness of triangular mounts (T1) reduced stress 3.57 times more effectively than circular ring thickness (T2) highlighting a critical symmetry-breaking feature in support geometry. This approach enables rapid and effective design modifications without complex optimization simulations. The study demonstrates that restoring structural symmetry through targeted reinforcement is essential to mitigate fatigue failure caused by asymmetric loading.

Hydrogen demand estimation for various transport modes supports policy and decision-making for the transition towards a sustainable low-carbon future transport system. It is one of the major factors that determine infrastructure construction production and distribution cost optimisation. Researchers have developed various methods for modelling hydrogen demand and its geographical distribution each based on different sets of predictor variables. This paper systematically reviews these methods and examines the key variables used in hydrogen demand estimation including the number of vehicles travel distance penetration rate and fuel economy. It emphasises the role of spatial analysis in uncovering the geographical distribution of hydrogen demand providing insights for strategic infrastructure planning. Furthermore the discussion underscores the significance of minimising uncertainty by incorporating multiple scenarios into the model thereby accommodating the dynamic nature of hydrogen adoption in transport. The necessity for multi-temporal estimation which accounts for the changing nature of hydrogen demand over time is also highlighted. In addition this paper advocates for a holistic approach to hydrogen demand estimation integrating spatiotemporal analysis. Future research could enhance the reliability of hydrogen demand models by addressing uncertainty through advanced modelling techniques to improve accuracy and spatial-temporal resolution.

Hydrogen is increasingly recognized as an element in the effort to decarbonize the energy sector. Within the development of large-scale supply chain the storage phase emerges as a significant challenge. This study reviews Life Cycle Assessment (LCA) literature focused exclusively on hydrogen as an energy vector aiming to identify areas for improvement highlight effective solutions and point out research gaps. The goal is to provide a comprehensive overview of hydrogen storage technologies from an environmental perspective. A systematic search was conducted in the SCOPUS database using a specific set of keywords resulting in the identification of 30 relevant studies. These works explore hydrogen storage across different scales and applications which were classified into five categories based on the type of storage application most of them related to stationary use. The majority of the selected studies focus on storing hydrogen in compressed gas tanks. Notably 33 % of the analyzed articles assess only greenhouse gas (GHG) emissions and 10 % evaluate only two environmental impact categories including GHGs. This reflects a limited understanding of broader environmental impacts with a predominant focus on CO₂eq emissions. When comparing different case studies storage methods associated with the lowest emissions include metal hydrides and underground hydrogen storage. Another important observation is the trend of decreasing CO₂eq emissions as the storage system scale increases. Future studies should adopt more comprehensive approaches by analyzing a wider range of hydrogen storage technologies and considering multiple environmental impact categories in LCA. Moreover it is crucial to integrate environmental economic and social dimensions of sustainability as multidimensional assessments are essential to support well-informed balanced decisions that align with the sustainable development of hydrogen storage systems.

For low-carbon hydrogen to become a viable decarbonization solution the creation of a robust and effective market is essential. This paper examines the applicability of market reforms from the renewable energy natural gas and liquefied natural gas (LNG) sectors with a focus on pricing mechanisms business models and infrastructure access to facilitate hydrogen market development. Applying the Structure-Conduct-PerformanceRegulation (SCP-R) framework and informed by stakeholder insights we identify critical enablers for advancing the hydrogen market formation. Our analysis highlights the importance of innovative pricing strategies and regulatory measures incentivizing investment and managing risks. Establishing a market reference price for low-carbon hydrogen — akin to benchmarks in the natural gas and LNG sectors—is critical for ensuring transparency predictability and regional adaptability in trade. Additionally customized business models are also needed to mitigate volume risks for producers. Government interventions such as offtake agreements and the development of hydrogen hubs are indispensable for fostering competition and driving decarbonization.

Achieving a net-zero energy system in Europe by 2050 will likely require large-scale deployment of hydrogen and seasonal energy storage to manage variability in renewable supply and demand. This study addresses two key objectives: (1) to develop a modeling framework that integrates seasonal storage into a stochastic multihorizon capacity expansion model explicitly capturing tactical uncertainty across timescales; and (2) to assess the impact of seasonal hydrogen storage on long-term investment decisions in European power and hydrogen infrastructure under three hydrogen demand scenarios. To this end the multi-horizon stochastic programming model EMPIRE is extended with tactical stages within each investment period enabling operational decisions to be modeled as a multi-stage stochastic program. This approach captures short-term uncertainty while preserving long-term investment foresight. Results show that seasonal hydrogen storage considerably enhances system flexibility displacing the need for up to 600 TWh/yr of dispatchable generation in Europe after 2040 and sizing down cross-border hydrogen transmission capacities by up to 12%. Storage investments increase by factors of 5–14 which increases the investments in variable renewables and improve utilization particularly solar. Scenarios with seasonal storage also show up to 6% lower total system costs and more balanced infrastructure deployment across regions. These findings underline the importance of modeling temporal uncertainty and seasonal dynamics in long-term energy system planning.

Hydrogen storage in depleted gas reservoirs triggers geochemical and microbiological reactions at the caprockreservoir interface yielding significant implications on storage integrity. Acetogenesis is a microbial reaction observed during underground hydrogen storage (UHS) that produces acetate and converts it into acetic acid under protonation potentially impacting the UHS process integrity. For the first time this research explores the impact of the acetic acid + brine + caprock reaction on shale caprock mineralogy microstructure and physicochemical properties where this preliminary study has been conducted under ambient conditions to obtain an initial assessment of the impact. A comprehensive mineralogical and micro-structural characterization including scanning electron microscopy (SEM) energy dispersive X-ray spectroscopy (EDS) X-ray fluorescence (XRF) Xray diffraction (XRD) micro-computed tomography (micro-CT) and inductively coupled plasma mass spectrometry (ICP-MS) have been conducted to assess the mineralogical and microstructural changes in shale specimens saturated with brine solutions with a range of acetic acid percentages (5 % 10 % and 20 %) to find the maximum possible impact. According to the conducted mineralogical analysis (EDS XRF and XRD) there is a significant primary mineral dissolution during the acetic acid interaction where calcite and dolomite are the predominant minerals dissolved evidencing the significant impact of the acetic acid reaction on carbonate-rich caprock systems during UHS. However secondary mineral precipitation happened at high acidic concentrations (20 %). Interestingly other common minerals in reservoir rocks (e.g. mica pyrite) did not demonstrate rapid interactions with acetic acid compared to carbonates. The impact of these mineralogical changes on the caprock microstructure was then investigated through SEM and micro-CT and the results demonstrate substantial enhancements in porosity and microcracks in the rock matrix due to the calcite and dolomite dissolutions despite some microcracks being closed by secondary precipitations. This preliminary study evidences the significant impact of acidification on caprock integrity which may occur during the acetogenesis reaction in UHS environments. These effects should be carefully considered in field UHS projects to eliminate the risks.

The increasing need for environmentally friendly energy sources has contributed to the development of innovative technologies that also resolve environmental issues. Hydrogen can be produced in a number of ways including using fossil fuels biomass and renewable energy sources like wind and sun. Using renewable energy for water-based production is the most sustainable method of producing hydrogen. However since fresh water is scarce the main way to address this issue is to use wastewater. Although wastewater is frequently seen as an issue it could additionally be seen as a valuable source of energy as it has the potential to produce bio-hydrogen. The current review emphasizes the key conclusion of studies examining the viability of the generation of hydrogen from wastewater by applying a variety of technologies in order to investigate each method’s potential which effectively removes pollutants from wastewater addressing both environmental challenges of wastewater treatment as well as clean energy production. Hydrogen production from wastewater using sustainable lowenergy methods enhances energy recovery in treatment plants and promotes a circular economy. This lowcarbon hydrogen supports global decarbonization and simultaneously achieving pollutant degradation with advanced systems offers dual benefits over traditional wastewater treatment methods. The essential details of 7 emerging technologies their working mechanisms affecting parameters work advances advantages and disadvantages and their future prospects are taken into consideration in 2 distinct classes- light-independent and light-dependent technologies.