Optimal battery and hydrogen fuel cell sizing in heavy-haul locomotives

Global supply chains must be decarbonised as part of meeting climate targets set by the United Nations and world leaders. Rail networks are vital infrastructure in passenger and freight transport, however, have not received the same push for decarbonisation as road transport. In this investigation, we used real world data from locomotives operating on seven rail corridors to identify optimal battery capacity and hydrogen fuel cell (HFC) power in hybrid systems. We found that the required battery capacity is dependent on both the available regenerative braking energy and on the capacity required to buffer surpluses and deficits from the HFC. The optimal system for each corridor was identified, however it was found that one 3.6 MWh battery and 860 kW HFC system could service six of the seven corridors. The optimal systems presented in this work suggest an average of around 5 h of battery storage for the HFC power, which is larger than the 2 h previously reported in literature. This may indicate a gap between purely theoretical works that use only route topography and speed, and those that employ real world locomotive data.