Research On The Environmental Impact Of Beijing Urban Buses Travel From A Life Cycle Perspective

Public transportation is one of the key measures to relieve urban traffic congestion because of its higher efficiency than private cars. However, as more and more traditional fuel vehicles were still used in recent years, the public transportation sector also consumed more and more fuels. Therefore, the new energy buses, including Natural Gas Buses, Diesel Hybrid Electric Buses and Battery Electric Buses gradually become the first choice for public bus system, as in the driving stage, the new energy buses show the perfect performance in energy conservation and emissions reduction. But, the other life cycle stages of new energy buses are not well studied, such as manufacturing stage and energy production stage. Furthermore, there are still gaps between the transportation function of new energy buses and fuel oil based buses, including passenger carrying capacity. Therefore, taking the basic service function of buses into consideration, this study employs Life Cycle Assessment method to compare the environmental impact of new energy and fuel buses, for sustainable public transportation planning. This study includes4sectors.First of all, combined with the urban traffic status, residents travel demand and local traffic management policies, this study made a survey on the key factors of urban public transportation in Beijing. The main parameters of urban buses system are investigated in order to provide basic data for environmental assessment of urban public transportation in the next step.Secondly, the urban public transportation travel service is modeled and the life cycle environment impact of different buses is calculated with one LCA tool:Gabi6. The conclusion shows that the environmental impact is the largest in the driving stage for all target products in this study:Conventional Diesel Buses (CDB), Natural Gas Buses (NGB) and Diesel Hybrid Electric Buses (DHEB), followed by the fuel production stage. Meanwhile, the electricity generation stage is the largest in environmental impact for Battery Electric Buses (BEB). The other life cycle environmental impact of different buses are all relatively small, including materials production, parts manufacturing, products assembly and transport distribution stage.Thirdly, this study set two scenarios, bus with the air conditioner on or off, and the comprehensive environmental impact of different types of buses are quantified. The results indicate that, DHEB and BEB are more sensitive to the function of air conditioning than CDB and NGB. The order of comprehensive environmental impact of different types of buses is BEB>CDB>DHEB>NGB under the condition without air conditioning operation or with air conditioning operation. The sensitivity analysis results indicated that, the fuel prices and passenger carrying capacity are of great significance for life cycle environmental impact of urban public transportation.At last, the travel service of Beijing public buses service is taken as a case study here. In this framework, the life cycle environmental benefits of three types of new energy buses are evaluated. Combined with environmental benefits of different types of new energy buses, the structure of buses travel of Beijing in2017is predicted.