Analysis of Energy Dissipation in an Electric Transit System

Abstract

Reducing energy consumption in electrified transit systems is becoming increasingly important as energy prices rise and environmental concerns become more prominent. In electrified transit systems, significant savings can be accomplished by utilizing braking energy. Energy from regenerative braking can be used to power vehicles via the traction supply system, or stored on board vehicles using energy storage devices. The effectiveness and energy savings of regenerative braking or on board energy storage is dependent on the nature of the system, particularly the vehicle drive cycles and service frequency. The paper describes an analysis methodology developed to consider energy flows in an electrified transit system, hence enabling the potential benefits of regenerative braking and energy storage devices to be assessed.

Flywheel Energy Storage System in Italian Regional Transport Railways: A Case Study

“…Due to inherent differences in the convoy Rupp et al studied and our own convoy model, our data for no-gradient conditions reports efficiencies between 16.7% and 35.6% depending on the storage nominal power. Barrero et al [27] modelled a metro network with stationary and on-board Energy Storage Systems (ESS) and found that reduction achieved with stationary ESS varies as a function of the traffic conditions, ESS size, and ESS distribution along the line. With efficient metro trains, savings were 18.7%, 25.1%, and 36.4% at high, moderate, and low traffic volumes, respectively.…”

“…The train runs a track of 86 km, for a cumulative length of 172 km and 63 stations. Studies on energy storage in railway applications [22][23][24][25][26][27][28][29] have been carried out; comparisons with the results found in our studies are examined in Section 4. The altimetric plot is symmetric, i.e., it runs the same path in both ways to eliminate the need to include the potential energy difference between the starting and finishing stations.…”