Preliminary Feasibility Study on Energy Economy of Electric-Bus Rapid Transit System

Abstract

Since 2017, initiation of electric metrobuses is projected, especially in USA. Resulted aid in air pollution is also striking drive to switch fuel-sourced metrobusses into electric ones. Therefore, according to Istanbul's promising potential with long Bus Rapid Transit Systems (BRT) and existing problem with high levels of air pollutants, integration of Electric Bus Rapid Transit System (e-BRT) offers a core solution. This study is the preliminary feasibility analysis of e-BRT for the longest round-route of Sogutlucesme-Beylikduzu (SB-BS), Istanbul, Turkey. For e-BRT adaptation, two actively on service metrobus models of Mercedes Benz™ are selected as 18-m-long Conecto G with 150 passenger and 21-m-long CapaCity L with 191-passenger. Real-time 3-axis acceleration, 3-axis magnetometer, latitude, longitude and barometric height measurements on the selected round-route of SB-BS under dynamic passenger load are collected and analyzed. 3D-accelerometer measurements are filtered with 8^th order low-pass and high-pass Butterworth filters with respective cut-off frequencies of 4.5 Hz and 100 Hz prior to each integration, FFT, Periodogram, PSD, Welch-PSD and RMS analysis on MATLAB. The major purpose of acceleration measurements is to form a reference energy state of current fuel-sourced BRT so that future e-BRT system can be compared and feasibility of e-BRT can be conducted. Meanwhile, magnetometer measurements are performed to form a comparison with future e-BRT system. This will allow to detect higher existing magnetic field in e-metrobus so that necessary precautions can be taken for passenger safety. Finally, latitude, longitude and barometric height measurements are collected in order to map 3D route, inclines and maneuvering locations and to provide additional information on results of acceleration analyses. Moreover, to detect the most challenging route that e-BRT need to cover, maximum energy consuming route is extracted upon collected and analyzed current BRT measurements. All comparisons are performed upon requested original fuel-sourced BRT on active service durations and on the exact date of the measurements. Results indicate that the energy dissipation is maximum on CapaCity L at rear seat without suspension on Beylikduzu-Sogutlucesme (BS) route direction. Statistically, required energy need to cover SB route is greater than BS due to steep inclines. It is found that 37.5% of displacement power is stored in suspension systems. Reported peak magnetic field of electric vehicles is greater than BRT of Istanbul by only 98 µT.