Energy Savings in Public Transport

Growing pollution levels and traffic congestion in major cities are becoming delicate issues that could be eased by more efficient public transit systems. To reduce emissions, electric powered vehicles are in use in many cities. Depending on the number of commuters and on the available infrastructure, different types of electric vehicles (electric buses, trolleys, trams, etc.) can be applied. Although these mass transit vehicles enable large reductions in terms of emissions, their energy efficiency could be significantly improved. This improvement can be reached by hybridization of their drive train with the inclusion of an energy storage system (ESS) for energy recovery purposes. Recent studies have shown that up to 40% of the energy supplied to electrical rail guided vehicles could be recovered through regenerative braking. This energy can be sent to other vehicles on the line, provided that they will consume it simultaneously; however, this is infrequent for tram networks, where the light traffic density entails a small percentage of braking energy reuse. Supercapacitor-based ESSs are ideal for this kind of applications where high peak powers are frequent. Their low internal resistance permits a high charge/discharge cycle efficiency, while their electrostatic nature allows a long lift time. Hybridizing the tram drive train with supercapacitors can serve several purposes, depending on the particular aims, such as peak power shaving or overhead line voltage stabilization. Toward this aim, a specific control strategy and a particular sizing are needed. This article focuses on the development of an ESS oriented to energy savings and proposes different ESSs, ranging from 0.91-1.56 kWh, suitable for a 30-m long tram. To configure the system regarding energy content, voltage variation, maximum current, and power losses, a model of the tram, network, and substations power flow has been developed in a Matlab/Simulink environment. Results obtained in energy savings are described, and a case study is provided. Sections are devoted to system parameters, determination of energy storage system needed, design criteria, energy considerations, proposed configurations, results, and conclusions.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/15566072
• Authors:
  • Barrero, Ricardo
  • Van Mierlo, Joeri
  • Tackoen, Xavier
• Publication Date: 2008-9

Language

• English

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 26-36
• Serial:
  • IEEE Vehicular Technology Magazine
  • Volume: 3
  • Issue Number: 3
  • Publisher: Institute of Electrical and Electronics Engineers (IEEE)
  • ISSN: 1556-6072
  • Serial URL: http://ieeexplore.ieee.org/xpl/tocresult.jsp?isnumber=34840

Subject/Index Terms

• TRT Terms: Electric buses; Electric trains; Electric vehicles; Energy storage systems; Light rail transit; Light rail vehicles; Public transit; Trolley cars
• Subject Areas: Data and Information Technology; Passenger Transportation; Public Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 01117675
• Record Type: Publication
• Files: TRIS
• Created Date: Dec 30 2008 12:32PM