Li-Ion Battery-Based Hybrid Diesel-Electric Railway Vehicle: In-Depth Life Cycle Cost Analysis

In this study, the life cycle costs of railway projects involving hybrid diesel-electric vehicles are analysed. Specifically, the analysis focuses on the comparison of 3 lithium-ion battery technologies (NMC, LTO and LFP) and 8 energy management strategies (including rule-based and optimization-based strategies). In order to develop this analysis, a methodology that returns the life cycle cost of each proposed case is presented. The methodology includes the optimization of the diesel generator and lithium-ion battery sizing. A scenario based on a real railway line is introduced, and the obtained results are compared to a traditional diesel-electric railway vehicle to develop a techno-economical discussion. The best lithium-ion battery technologies are found to be LTO and NMC, and the most appropriated strategy a state-machine controller optimised by a genetic algorithm approach. The best case obtains a life cycle cost reduction of the 4.0% and diesel savings of the 13.7% compared to a traditional diesel-electric railway vehicle. The proposed analysis is claimed to be potentially helpful for the cost-optimal design and operation definition of powertrains for hybrid railway vehicles.