Study On Calculation Theory And Application Of Carbon Emission Reduction Of Urban Rail Transit

Increased urbanization and an ever-increasing demand for improved transport links through cities,has necessitated the need for urban rail transit operations.In recent years,the rail transit operating mileage and passenger flows in China are growing significantly,which has played a fundamental role in tackling traffic congestion,smoothing travel experience and contributing to the energy conservation and emissions reductions in the field of transportation.The carbon emission reduction is part of the externality benefit of urban rail transit,and implementation of carbon trading can provide the means for the internalization of such environmental externalities.Moreover,the initial development of the domestic carbon trading market also offers feasibility of carbon emission reduction strategies.A reasonable carbon emission reduction model and reliable measurements are two necessary and vital parts to implement carbon trading scheme.However,there currently is an existing gap in determining the carbon emission reduction triggered by rail transit in China.Therefore,a methodology of measuring carbon emission reduction was proposed to evaluate and quantify the carbon emission reduction effect due to the newly-built rail transit line,which was of great significance for the implementation of carbon trading and sustainable development of rail transit.Based on the theory of carbon emission reduction,a methodology of measuring carbon emission reduction was recommended,aiming to quantify the carbon emission reduction triggered by rail transit.The research has been carried out in this paper,and the main conclusions were drawn as follows:(1)A model of carbon emission reduction based on the theory and algorithm of transportation mode transfer' was established.After the opening of a rail transit line,passengers previously using cars,buses,and other modes of transport switched to rail transit,which leads to emissions reductions.Based on this,the scope of the calculation was defined as emissions from energy consumption in the operational phase of the vehicles considered and the emissions from electricity during fossil fuel consumption at power stations.The comparison baseline was defined as the number of emissions caused by other modes of transportation without rail transit line.The emissions reductions were calculated by comparing the emissions differences corresponding to the passenger travel paths when using rail transit or not.The project boundary was the entire geographical boundary of the urban area in which the MTR operated.At the same time,the carbon emission of the rail transit line measured which included not only the emissions of the line and station but also the fuel emissions of the metro depot.(2)A carbon emission reduction model considering optimal park-and-ride(P+R)facility location and charging strategies were proposed.The attractiveness index was introduced to measure the attractiveness of the P+R facility,and a two-stage model of P+R location was set up.Moreover,a bi-level genetic model considering congestion degree of rail transit lines was designed,in which the corresponding benefit of carbon emissions reductions was included in the profit of parking operators.The optimization of P+R charging policies could promote the P+R commute mode to become increasingly common.(3)The collection and calibration of parameters regarding carbon emission reduction were achieved.A standardized survey method was designed to obtain the passenger travel mode and travel distance data before and after the operation of the rail transit line.In consideration of cost and feasibility,questions relating to personal characteristics,current trip paths by using rail transit to reach target destinations,and the alternative trip paths before the new lines were designed in the questionnaire.The questionnaires in field survey were conducted to obtain passengers' trip origin and destination,travel mode and interchange nodes.A network analysis method was used to calculate the travel distances of passengers for different modes of transportation in a geographic information system(GIS).Additionally,the calculation model and algorithm of carbon emission reduction in rail transit were applied,and its parameter estimation was made as well.(4)Estimated carbon emission reductions for four typical urban rail transit lines and connection facilities in Beijing,and calculated the contribution of 2017 Beijing urban rail transit lines and connection facilities to carbon emissions reduction in the city.The AFC card data of Beijing Metro Lines and large data mining techniques are applied to allocate passenger flow,therefore precisely calibrating the carbon emission factor relating to passenger-kilometer.Furthermore,the large data mining and processing technologies were combined with the artificial investigation,taxi fuel consumption algorithm using VSP approach,taxi GPS data,and ArcGIS software,the average fuel consumption per hundred kilometers in Beijing Metro network is achieved.Additionally,the passenger-kilometer carbon emission factors of taxis were determined to estimate the carbon emission reduction of urban rail transit and connecting facilities.(5)The carbon emission reduction of four representative rail transit lines and associated connection facilities in Beijing were estimated.Based on the model and the travel paths of the sampled passengers,the annual carbon emissions reductions and emissions intensity indices of Beijing Metro Lines 6,9,10,and 15 were calculated.The results show that four subway lines in 2014 in Beijing reduced 0.529 million t CO2 in total.According to four representative lines,a direct sample expanding method was adopted.Therefore,the carbon reduction of Beijing Metro network with typical connection facilities,and the carbon emission reduction per capita intensity of each line was calculated.In the light of the proposed estimation model and field survey,some worthy conclusions were drawn.In 2007,the carbon emission reduction of Beijing Metro Lines 1,4,5,13,and 14 were the highest,and most suburban lines ranked at the bottom of the list.The total emissions reductions of Beijing Metro network were 2.5 million t CO2,of which the P+R facilities were about 9014.5 t CO2.The main carbon reduction specifications based on the number of parking spaces were put forward.The carbon reduction effectiveness of P+R facilities was defined by a quantitative way,and the emissions reductions were about 0.91t CO2 one lot per year.