The road transport sector is undergoing major transformations as a consequence of the compelling need of reducing carbon dioxide emissions, with many countries imposing limits to production and sale of fossil fuel vehicles in the near future. If produced through clean energy, hydrogen could represent a feasible solution for reducing emissions of long haul heavy duty road transport: one possible exploitation of hydrogen is in proton exchange membrane fuel cells (PEMFC), which can also provide an improvement in powertrain efficiency compared to internal combustion engines. Numerical simulations are a necessary tool in supporting the development of PEMFC systems, enabling their systematic analysis, fine-tuning, and optimization.