Uncovering the CO_(2)emissions of vehicles:A well-to-wheel approach

Carbon dioxide(CO_(2))from road traffic is a non-negligible part of global greenhouse gas(GHG)emissions,and it is a challenge for the world today to accurately estimate road traffic CO_(2)emissions and formulate effective emission reduction policies.Current emission inventories for vehicles have either low-resolution,or limited coverage,and they have not adequately focused on the CO_(2)emission produced by new energy vehicles(NEV)considering fuel life cycle.To fill the research gap,this paper proposed a framework of a high-resolution well-to-wheel(WTW)CO_(2)emission estimation for a full sample of vehicles and revealed the unique CO_(2)emission characteristics of different categories of vehicles combined with vehicle behavior.Based on this,the spatiotemporal characteristics and influencing factors of CO_(2)emissions were analyzed with the geographical and temporal weighted regression(GTWR)model.Finally,the CO_(2)emissions of vehicles under different scenarios are simulated to support the formulation of emission reduction policies.The results show that the distribution of vehicle CO_(2)emissions shows obvious heterogeneity in time,space,and vehicle category.By simply adjusting the existing NEV promotion policy,the emission reduction effect can be improved by 6.5%-13.5%under the same NEV penetration.If combined with changes in power generation structure,it can further release the emission reduction potential of NEVs,which can reduce the current CO_(2)emissions by 78.1%in the optimal scenario.

Feasibility of hydrogen fuel cell technology for railway intercity services:a case study for the Piedmont in North Carolina

Diesel fuel combustion results in exhaust containing air pollutants and greenhouse gas emissions.Many railway vehicles use diesel fuel as their energy source.Exhaust emissions,as well as concerns about economical,alternative power supply,have driven efforts to move to hydrogen motive power.Hydrogen fuel cell technology applied to railways offers the opportunity to eliminate harmful exhaust emissions and the potential for a low-or zero-emission energy supply chain.Currently,only multiple-unit trains with hydrail technology operate commercially.Development of an Integrated Hybrid Train Simulator for intercity railway is presented.The proposed tool incorporates the effect of powertrain components during the wheel-to-tank process.Compared to its predecessors,the proposed reconfigurable tool provides high fidelity with medium requirements and minimum computation time.Single train simulation and the federal government’s Greenhouse gases,Regulated Emissions,and Energy use in Transportation(GREET)model are used in combination to evaluate the feasibility of various train and powertrain configurations.The Piedmont intercity service operating in North Carolina is used as a case study.The study includes six train configurations and powertrain options as well as nine hydrogen supply options in addition to the diesel supply.The results show that a hydrail option is not only feasible,but a low-or zero-carbon hydrogen supply chain could be possible.