Gabriele Guglielmo Gagliardi

Hydrogen-battery railway powertrains are promising for regional lines where full electrification is difficult or costly. This work presents a train-level PEMFC-battery-pantograph model supported by experimental PEMFC data. The route-driven inverse simulation includes an experimentally informed voltage-loss and equivalent-life layer, a route-dependent 3 kV DC pantograph source, and a thermal-management model for the fuel cell, battery and cooling auxiliaries. Laboratory tests define voltage-loss and recovery parameters, separating irreversible active-time loss from reversible loaded/unloaded voltage changes. The model is applied to the Siena-Chiusi route and compares three EMS strategies: Battery-priority, Nominal-FC and High-load-penalty. With the experimental correction active, Battery-priority and High-load-penalty reduce hydrogen consumption by 27.7% and 21.6% versus Nominal-FC, while final SOC remains close to 81–82%. Equivalent PEMFC lifetime ranges from 4.89 to 6.79 years, and the 20-year cost ranges from 5.41 to 6.91 MEUR.

Anion exchange membrane water electrolysers (AEMWEs) are promising for renewable hydrogen production, but coupling with intermittent photovoltaic (PV) power can accelerate degradation and is still poorly represented in system-level models. This work develops a degradation-aware framework for PV-coupled AEMWEs, calibrated using single-cell cycling tests and electrochemical impedance spectroscopy. Experiments showed independent evolution of ohmic and polarization resistances, while the cell voltage at 1 A cm⁻² increased by about 201 mV. These trends were implemented in a reduced-order model including separate resistance growth, partial ohmic recovery by electrolyte replenishment, and discrete start–stop penalties. Three membrane–electrode assemblies, NR, PK, and NiA, were analysed under hourly PV input for Rome using 1×10, 2×5, and 10×1 kW layouts. Higher modularity improved PV utilization but increased start–stop events from about 360 to 3600 yr⁻¹. NiA achieved 276.47 kg yr⁻¹ H₂ with 0.92% curtailment, while stack replacement remained economically penalizing under the adopted techno-economic assumptions overall.

This study investigates the potential of anion exchange membrane (AEM) electrolysers for hydrogen production, focusing on operating conditions, membrane treatment, manufacturing (with or without polyketone reinforcement), and thickness. Physical, mechanical, and energetic tests were performed. Hydroxide uptake was higher with an alkaline solution than with deionized (DI) water (12.5±4.4% vs. 1.4±0.6%). Energetic analysis evaluated the impact of flow rate, temperature, and hydroxide concentration. Increasing the flow rate reduced performance (11% at 140 mA/cm2), likely because the shorter residence time on the electrodes’ active area lowered hydroxide ion availability for the electrochemical semi-reactions, while higher temperature and concentration improved performance (+15/29% at 140 mA/cm²) due to enhanced electrode catalytic activity and higher membrane ionic conductivity. Membrane activation via 24 h KOH immersion was compared with a NaCl pre-treatment, which enhanced anion conductivity and reduced cell voltage by 7% at 140 mA/cm². Optimal conditions were 4 mL/min flow rate, 60°C, and 1 M KOH. Polyketone addition did not affect energetic performance, whereas thickness had a significant influence. Using nickel instead of platinum increased voltage by 56% but reduced costs by 99%, making it attractive for commercial applications. A MATLAB/Simulink model was calibrated with experimental data, showing good agreement with deviations within 0.1–5%.

This paper proposes an analysis of different logics (heuristic and linear) of managing renewables scenarios including two different operating conditions and their relative degradation: fixed and variable point. The synergy between two storage technologies, such as Li-ion batteries and the hydrogen power-to-power solution (electrolyzer, H₂ tank, and fuel cells), is evaluated to ensure the balance of the power grid. This paper presents a numerical model of the smart grid developed in MATLAB/Simulink. A detailed performance evaluation of each component was performed to meet an electrical load (30 kW-peak) of a smart renewable energy community. From the optimization process, a fuel cell of 6 kW, an electrolyzer of 18 kW, a tank of 40 m³ at 200 bars, as well as a battery of 75 kWh were selected. The fuel cell operates during autumn and winter due to the lack of photovoltaic power generation, while its contribution is reduced during the summer period. In the heuristic logic, the minimum and maximum hydrogen levels are 18% and 60% of the tank volume (40 m³), respectively, while in the linear logic, they are 33% and 65%. The average value of the state of charge (SOC) of the battery is similar in both logics (0.51 vs. 0.53). Regarding hydrogen produced from the electrolyzer, the linear logic allows it to produce a quantity 7% higher than the heuristic one; therefore, the linear logic allows it to properly manage the electrochemical systems. The dynamic operation results in more significant degradation of hydrogen systems, making them less suitable; thus, to preserve the devices (up to 25% of lifetime more), a fixed-point operation is recommended. The cost comparison does not show relevant differences between the two scenarios, while a steep increase in the costs is shown when the fuel cell is operated in dynamic mode. Finally, the total emissions associated with renewable microgrids are 30 times lower than the traditional grid scenario, demonstrating the potential of renewable energy communities.

This study presents a techno-economic analysis of hydrogen transportation via liquid organic hydrogen carriers by road, comparing this option with compressed hydrogen (350 bar) and liquefied hydrogen. The analysis includes the simulation of hydrogenation and dehydrogenation reactors for the dibenzyltoluene/perhydro-dibenzyltoluene system using ASPEN Plus, along with a cost assessment of compression, liquefaction, and trucking. A sensitivity analysis is also carried out, evaluating hydrogen transport at varying daily demand levels (1, 2, and 4 t/d) and transport distances (50, 150, and 300 km), with varying electricity prices and capital expenditures for hydrogenation and dehydrogenation units. Results indicate that compressed hydrogen is the most cost-effective solution for short distances up to 150 km, with a levelized cost of transported hydrogen ranging from 1.10 to 1.61 EUR/kg. However, LOHC technology becomes more competitive at longer distances, with LCOTH values between 1.49 and 1.90 EUR/kg at 300 km across all demand levels. Liquefied hydrogen remains the least competitive option, reaching costs up to 5.35 EUR/kg, although it requires fewer annual trips due to higher trailer capacity. Notably, at 150 km, LOHC transport becomes more cost-effective than compressed hydrogen when electricity prices exceed 0.22 EUR/kWh or when the capital costs for hydrogenation and dehydrogenation units are minimized. From an environmental perspective, switching from compressed to liquid hydrogen carriers significantly reduces CO₂ emissions—by 56% for LOHCs and 78% for liquid hydrogen—highlighting the potential of these technologies to support the decarbonization of hydrogen logistics.

This study presents a techno-economic feasibility of hydrogen transportation via liquid organic hydrogen carriers by road, making a comparison with compressed hydrogen (350 bar) and liquefied hydrogen. The analysis includes the simulation of hydrogenation and dehydrogenation reactors for the dibenzyltoluene/perhydro-dibenzyltoluene system using ASPEN Plus, along with a cost assessment of compression, liquefaction, and trucking. A sensitivity analysis evaluates hydrogen transport at varying daily demand (1 t/d, 2 t/d, and 4 t/d) and transport distances (50, 150, and 300 km). Results indicate that compressed hydrogen is the most cost-effective solution for short distances up to 150 km, with a levelized cost of transported hydrogen ranging from 0.63 to 1.55 €/kg. However, liquid organic hydrogen carrier technology becomes more competitive as transport distance increases, reaching values of 1.37–1.93 €/kg at 300 km for all hydrogen demand levels. Liquefied hydrogen remains the least competitive option, with costs reaching up to 6.48 €/kg, although it requires fewer annual trips by maintaining a fixed annual hydrogen demand.

The potential of applying a floating PV (FPV) system in an Italian context (namely, Cecita dam and Mucone hydroelectric power plants) is studied. The additional PV energy production, as well as the effect of non-evaporated water on the productivity of the hydropower plant, is analyzed by varying the basin surface coverage. The simulations highlight that the amount of additional hydroelectricity is quite small if compared to the non-FPV system, reaching about 3.56% for 25% basin surface coverage. However, the annual PV energy production is noticeable even at low coverage values. The expected gain in electricity production in the case of 25% basin surface coverage with the FPV plant rises to 391% of that of the actual hydropower plant. This gain becomes even larger if a vertical axis tracking system is installed and the increase is about 436%. The economic analysis confirms that the production costs (USD/kWh) of FPV systems are comparable to those of land-based PV (LBPV) plants, becoming smaller in the case that a tracking system is installed. In particular, the best solution is the one with 15% coverage of the lake. In this case, the levelized cost of electricity for the LBPVs is 0.030 USD/kWh and for the FVPs, with and without tracking, it is equal to 0.032 and 0.029 USD/kWh, respectively.

The study utilizes open-access data to generate power demand curves for a hybrid automotive system, testing twelve configurations with three different energy management strategies and four values for the degree of hybridization (DOH), the latter representing the share of the total power of the vehicle powertrain supplied by the battery. The first control logic (Battery Main—BTM) uses mainly batteries to satisfy the power demand and fuel cells as backup, while in the other two controllers, fuel cells operate continuously (Fuel Cell Main—FCM) or within a fixed range (Fuel Cell Fixed—FCF) using batteries as backup. The results are assessed in terms of H₂ consumption, overall system efficiency, and fuel cell predicted lifespan. The battery is heavily stressed in the BTM and FCF logics, while the FCM logic uses the battery only occasionally to cover load peaks. This is reflected in the battery’s State of Charge (SOC), indicating different battery stress levels between the BTM and FCF modes. The FCF logic has higher stress levels due to load demand, reducing battery lifetime. In the BTM and FCM modes, the fuel cell operates with variable power, while in the FCF mode, the fuel cell operates in a range between 90 and 105% of its rated power to ensure its lifetime. In the BTM and FCM modes, hydrogen consumption decreases at almost the same rate as the DOH increases, due to a decrease in battery capacity and a smaller amount of hydrogen being used to recharge it. In contrast, the FCF control logic results in a larger fuel consumption when the DOH decreases. In terms of FC durability, the FCF control logic performs better, with a predicted lifetime ranging from 1815 h for DOH = 0.5 to 2428 h for DOH = 0.1. The FCM logic has the worst performance, with a predicted lifetime of 800 to 808 h, being almost insensitive to the DOH variation. Simulations were performed on two different driving cycles, and similar trends were observed. Simulations taking into account fuel cell (FC) performance degradation showed an increase in hydrogen consumption of approximately 38% after 12 years. Overall, this study highlights the importance of optimizing control systems to improve the performance of fuel cell hybrid vehicles, also taking into account the component of performance degradation.