Evaluating The Low Carbon Management Of Urban Public Transport Via Life Cycle Assessment

With the rapid development of urban population and economy,large and medium-sized cities are facing increasingly severe environmental challenges.As one of the most important environmental impacts and carbon emission contributors to the city,transport infrastructure and operating system which play a crucial role in energy conservation and emission reduction target at the city or national level.As the country's first pilot city for low-carbon transport system,Shenzhen has implemented a series of energy-saving and emission-reduction measures in the development of low-carbon transport,especially in urban public transport system.The purpose of this study was to conduct a comprehensive evaluation study on the effect of low carbon management in Shenzhen public transport system and put forward corresponding improvement measures and management countermeasures.The obtained results from the study revealed that a great significance could be made to the green development of urban transport system and the improvement of urban environmental quality.This study designed a framework and measurement method for energy consumption and carbon emissions of public transport system based on the theory of life cycle method,including rationally setting evaluation object and scope,screening and identifying major data lists and sources,conducting environmental impact assessment and prediction analysis,and finally completing quantitative evaluation of the effectiveness of low-carbon management of various low-carbon public transport technical measures and policy plans in Shenzhen.The life cycle inventory data mainly come from on-site investigations,statistical analysis,and data documents,including measured data on energy consumption of buses,and subway stations including the traction energy consumption;planning and construction of bus systems?volume?,operating routes,transportation distances,and vehicles relevant statistical data such as vehicle volume and type of buses,carbon impact factor data corresponding to energy consumption,etc.In addition,the study also estimated and predicted the carbon emissions of thepublic transport system and its carbon reduction potential?by 2030?through scenario analysis.The results of the study showed that due to the rapid growth of urban public transport,the carbon emissions from urban public transport system have rapidly increased from 0.70 Mt?million tons?in 2005 to 1.74 Mt in 2015,which was equivalent to the carbon emissions of the entire transportation sector in Jamaica.However,the current models which was implemented in 2005,including the increase in the proportion of new energy buses and the use of energy-saving facilities for subway have only been cumulatively reduced by 0.21 Mt CO₂e,until 2015.As of 2015,the reduction in carbon emission intensity?unit GDP carbon emission cumulative decline rate?of the public transport system was significantly lower than the overall emission reduction target of 32.5%in Shenzhen.Through scenario analysis,compared with the baseline scenario?according to the existing development model?,the new low-carbon model put forward through a series of improvement measures?further promote the existing low-carbon measures and increase the proportion of clean energy in the power plant energy structure,etc.?can significantly ease the carbon emissions pressure of the public transport system,and it was expected to reach the carbon emission reduction target of 2030?60%?.The results of this study can provide data and theoretical support for Shenzhen's transport sector to promote green development in a more in-depth manner,and also provide methodological reference for green transportation development and system evaluation in other cities.