Study of Potential and Utilization of Regenerative Power in Electric Railway

According to the Ministry of Land in Japan, the amount of carbon dioxide (CO
₂
) emitted when train transports a passenger for 1km is about 22g-CO
₂
/km in 2014 data [1]. This CO
₂
emission is about 1/6 of private cars and 1/5 of aircraft, which means that electric railways have environmental advantages. On the other hand, power consumption in the railway sector is 17.5TWh/year in fiscal 2018 [2], which corresponds to less than 2% of the total power consumption in Japan. Therefore, railway companies are taking up various methods to improve energy efficiency and reduce energy consumption more than know, to keep environmental advantage. Above all, the ratio of energy for train operation is large. so regenerative power is one of the main energy to reduce CO
₂
. East Japan Railway Company (JR East) also have been taking up to use regenerative power effectively as well. In this paper, the author shows potential of regenerative power possessed by JR East's trains, and then, report on the efforts that have been made for effective utilization of regenerative power and the prospects for the future.