Examining the influence of battery sizing on hydrogen fuel cell – battery hybrid rail powertrains (hydrail) for regional passenger railway transport using dynamic component models

To address the transportation sector’s contribution to climate change problems across North America (NA), passenger rail is an attractive solution. However, NA passenger rail traditionally relies on diesel motive power, which has been associated with causing health problems of noise, vibrations, and emissions. High costs of overhead and (or) third rail infrastructure have mostly precluded electrification. This paper examines the impact of battery size on fuel cell stack efficiency for hydrogen fuel cell – battery hybrid (hydrail) railway propulsion systems using dynamic simulations as opposed to existing simulations in the literature that rely on static efficiency values. The journey of the British Rail Class 156 diesel multiple unit is simulated over the round trip from Trehafod to Treherbert (UK) using a series hybrid architecture powertrain. Dynamic simulations at incremental battery masses were used to assess fuel cell efficiency, maximum power, and overall hydrogen consumption. Battery mass is employed as a proxy for power and energy capability of the battery. Results suggest that hydrail passenger railway systems work well, with hydrogen fuel cells handling most load dynamics. Hybridization with batteries works best and reduces fuel cell stack size and hydrogen consumption, with overall 64% stack efficiency.