Reducing CO₂ emissions in transport requires sustainable alternatives such as fuel cell electric vehicles. A critical challenge is the efficient and safe storage and fast refueling of hydrogen at 70 MPa. This study proposes a practical design-support tool to optimize hydrogen storage systems for heavy-duty vehicles with capacities up to 100 kg. A customizable, dynamic Matlab-Simulink model was developed, including all components from dispenser to onboard tanks, enabling evaluation of multiple design options. The aim is to provide clear guidelines to ensure fast, safe, and complete refueling compliant with SAE J2601-5 limits. Simulations showed Type III tanks deliver the best performance. The fastest refueling (~10 min) was achieved with shorter pipes, larger diameters and low temperatures (20 °C ambient, −40 °C dispenser), while Average Pressure Ramp Rate was maximized up to 9 MPa/min (220 g/s of hydrogen from the dispenser) without exceeding SAE limits for pressure and temperature.

Fuel cell electric vehicles represent a promising option for reducing greenhouse gas emissions from heavy-duty transport. In this context, integrating Hydrogen Refueling Stations (HRSs) into renewable-based microgrids represents a key strategy for ensuring sustainable hydrogen production. This study investigates the integration of an HRS into a photovoltaic-based microgrid supplying a fleet of 21 urban buses. A detailed hourly model of the photovoltaic system, battery storage, hydrogen generator, hydrogen storage, compression and refueling processes was developed. A multi-objective optimization was performed to minimize the Levelized Cost of Hydrogen (LCOH) while maximizing the Self-Sufficiency Rate (SSR). Three Energy Management Strategies (EMSs) were compared: hydrogen production using only renewable electricity, mixed renewable and grid electricity and grid-only electricity. Results reveal a marked economic penalty associated with achieving full self-sufficiency. Under the renewable-only EMS, the LCOH increases from 16.8 €/kg at an SSR of about 80% for the minimum-LCOH solution to 24.3 €/kg at an SSR of 100%. Under the MIXED-EMS, it increases from 12.3 €/kg at an SSR of about 47% to 22.7 €/kg at an SSR of 100%. When revenues from surplus electricity export are included, the corresponding LCOH values at 100% SSR decrease to approximately 15 €/kg, regardless of the EMS adopted. Compared with the emissions from the diesel-bus fleet, hydrogen buses could reduce emissions by about 12% with grid-based production and up to 99% with renewable hydrogen.