In-depth Life Cycle Cost Analysis of a Li-ion Battery-based Hybrid Diesel-Electric Multiple Unit

Abstract

This study analyzes the life cycle costs of railway projects involving hybrid diesel-electric multiple units, focusing on the influence of lithium-ion battery technologies and energy management strategies. Specifically, 3 lithium-ion battery technologies and 6 energy management strategies are proposed, leading to a sensitivity analysis composed of 18 cases. In addition, for each case an approach for the optimal sizing of the diesel generator and lithium-ion battery is proposed. A scenario based on a real railway line is introduced and the results are compared to a traditional diesel-electric multiple unit. Potential life cycle cost savings of 16.0% are obtained when deploying a global optimization-based energy management strategy and LTO batteries.

In-depth Life Cycle Cost Analysis of a Hydrogen Electric Multiple Unit

“…The proposed strategies split the power demand between the FC and the LIB. EMSs for hybrid vehicles are divided into rule-based and optimization-based (off-line and on-line optimization) strategies [6]. In the present paper 2 rulebased (RB) and 2 off-line optimization-based (OP) strategies are proposed.…”

“…This global optimization approach is based on an algorithm that calculates the optimal split factor (in terms of fuel consumption) between the FC and LIB for each time step based on Bellman's optimality principle. The resulting operation is characterized by frequent switches in the power split factor [6]. Therefore, in the current approach an additional term has been added to the optimization cost function J in order to ensure a smooth FC operation:…”

“…The performance of the HEMU is evaluated by means of a quasi-static simulation model developed in MATLAB. For further information regarding the model development, see [4], [6]. At this step, LIB characteristics (capacity and internal resistance) are set at Beginning-of-Life (BOL) values.…”

“…Therefore, it is concluded that when trying to reduce the cost of a hybrid railway vehicle, the effects of the EMS and ESS technology cannot be ignored. Previous scientific works have analysed the techno-economical suitability of H-DEMUs [6]- [9], BEMUs [7], HEMUs [7], or similar vehicles such as locomotives [10], [11]. From the reviewed studies, only the authors in [6] have developed a comprehensive LCC analysis comparing several EMSs and ESS technologies, but for the case of a H-DEMU.…”

“…Previous scientific works have analysed the techno-economical suitability of H-DEMUs [6]- [9], BEMUs [7], HEMUs [7], or similar vehicles such as locomotives [10], [11]. From the reviewed studies, only the authors in [6] have developed a comprehensive LCC analysis comparing several EMSs and ESS technologies, but for the case of a H-DEMU. Therefore, a lack of studies that propose an exhaustive LCC analysis for HEMUs is identified in the literature.…”