The energy use and environmental emissions of high-speed rail transportation in China: A bottom-up modeling

China's booming economy and rapid social development have resulted in the large-scale construction of high-speed rail (HSR) infrastructure. In addition to the reduced travel time and enhanced safety of HSR transportation, the construction of HSR infrastructure involves substantial up-front investments of capital and resources, yielding energy and environmental burdens. This study calculated the energy and environmental footprints of HSR transportation in China using a bottom-up modeling approach, with the Beijing-Shijiazhuang line selected as a case study. The results show that the cradle-to-gate energy and greenhouse gas (GHG) emissions of the HSR infrastructure are 104 PJ and 9.2 million tons of CO(2)e, respectively, mainly from steel manufacturing. For a high-speed train occupancy rate ranging from 100% to 30%, the cradle-to-wheel GHG emissions per passenger kilometers traveled is 54-178 g CO(2)e, enabling 10-60% and 46-73% mitigation compared to road vehicle travel and air transportation respectively. Opportunities to advance green HSR in China include cleaning the electricity supply available on the grids through renewable and nuclear power technologies, enhancing the ridership rate of high-speed trains by leveraging market and policy approaches such as the floating train fares mechanism and a cap-and-trade program for GHG emissions, and increasing the life-cycle mileage of high-speed trains. (C) 2019 Elsevier Ltd. All rights reserved.