Carbon Emission Boundary Analysis for High-speed Railway Signal System

Accurate quantification of carbon emissions of high-speed railway signal system is important for carbon emission estimation and the low-carbon development of high-speed railway. This paper considers the auxiliary activities of the signal system for the carbon emission calculation, and investigates the carbon emission boundary of the signal system. The proposed carbon emission calculation method for signal system is based on energy consumption. The carbon flow index of each device in the signal system is analyzed and calculated using the carbon flow theory. Taking the high-speed railway station of Lanzhou West in Gansu Province as a case study, this paper verifies the feasibility and effectiveness of the proposed method. The results show that the carbon emissions of the signal control and monitoring system are greatly related to the carbon emission factors of electricity, while the average carbon emission generated by the maintenance of the coded equipment is 0.12 kgCO2 ·d-1. The average branch carbon flow density among the devices in the signal system is 0.0076 kgCO2 ·kWh-1, and the node carbon potential of each device is equal to the branch carbon flow density. The carbon emission of each subsystem is associated with the type of the energy consumption. The indirect carbon emission caused by power consumption is the main component of carbon emission in the signal system. Direct carbon emissions from signal-system related activities are proportional to the primary energy consumption.