Utilasation of locomotive for mid-term energy storage

Abstract

The idea of a mid-term energy storage system (ESS) is becoming a popular option for improving the performance of energy conservation, power efficiency and the power grid. The goal of this research is to explore the possible benefits of utilisation of locomotive for mid-term energy storage. Various technologies are available in the market, including the Flywheel energy storage system (FESS), which is more appealing due to energy storage capacity, regular discharge cycles, reduced discharge costs for a few minutes, long lifespan and ongoing research and development. In this work, the efficacy of integration of FESS onto a locomotive power system for energy harvesting is evaluated. First, the model of the railway power network is presented. Based on the data available from the locomotive, the sizing of the FESS is done. The proposed scheme absorbs the braking energy generated. The benefits of feeding the recovered energy back into the railway power network when the train moves from a plane horizontal surface to steep gradient are investigated. The contribution of the evacuated power from the FESS to the catenary line is also appraised. The effectiveness of the proposed scheme is technically feasible for trains operating between Ermelo Coalfields to Ports of Richards Bay (RCB). The network is hampered by limitations on the power supply and regular faults, resulting in service delays. Feasibility to use FESS will potentially improve energy on-time delivery between traction stations. The results show that the use of flywheel energy storage technology would save the rail operators 25 % of their energy on class 19E locomotives. Therefore, for feasibility validation, this scheme may be feasible for implementation at a prototype level. This scheme will unburden the supply systems as the stored energy can be evacuated into the distribution networks. Furthermore, the effectiveness of this scheme will augment the supply during the irregular peak power that is often experienced in the railway connected system.