Performance Comparison between Solid Oxide Fuel Cell-Battery and PEM Fuel Cell-Battery Powered Locomotives for application in Indian Railways

The paper aims to analyze the feasibility of replacing the diesel locomotives with solid oxide fuel cell-battery-hybrid energy system (SOFC-battery-HES) to drive the inter-city passenger (ICP) trains in India. For this analysis, a comparison of the SOFC-battery-HES with an equivalent proton exchange membrane fuel cell (PEMFC)-battery-HES is carried out in terms of four performance indices namely, capital cost (CC), operational cost (OC), durability, and their environmental impact with respect to carbon emissions. For cost comparison, a design optimization model (DOM) is firstly formulated to determine the ratings of the SOFC and battery such that the designed SOFC-battery-HES can supply the power demand of ICP trains. The objective of optimization is to minimize the total cost which is the summation of the CC and OC of the SOFC-battery-HES. To regulate the distribution of load in the HES, a rule-based energy management strategy (EMS) is developed and is used as a subroutine in the particle swarm optimization-based solution approach to solve the DOM. The CC and OC of the SOFC-battery-HES obtained through optimization are now compared with the corresponding costs of an equivalent PEMFC-battery-HES. Besides cost comparison, the durability and carbon emissions of the HESs when advocated in Indian Railways are also examined. The simulation study is carried out using the data of the diesel locomotive type WDM-7 and the drive cycle of a currently operating ICP train of Indian Railways.