Energy consumption and well-to-wheels air pollutant emissions of battery electric buses under complex operating conditions and implications on fleet electrification

Abstract Electrification has been rapidly promoted to transform the energy source for public transit buses. Among all electric technologies penetrating the public bus fleet, battery electric buses (BEBs) dominates the market. Nevertheless, real-world energy consumption (EC) is of great concern, since BEBs are often used under congested conditions that may affect their energy and environmental benefits. This study proposes an operating mode binning method to assess on-road EC and well-to-wheel (WTW) air pollutants emissions of BEBs under complex real-world usage patterns. Second-by-second EC and operating data of two BEBs demonstrated in Macao, China is adopted to establish the EC profiles under each micro modes. Results show that EC value would be below zero in certain operation modes with negative vehicle specific power values, which suggests the regenerative brake system is effectively functioning under deceleration conditions. Average EC are estimated to be 1.7 to 4.1 kWh km −1 for BEB12 and 1.2 to 2.9 kWh km −1 for BEB10 (i.e., vehicle length of 12 m and 10 m), respectively, under all operating conditions (i.e., 18 various patterns) by average speed, loading mass and air conditioner usage. The large variation in real-world EC would proportionally affect WTW emissions of carbon dioxide (CO 2 ) and air pollutants from BEBs. When deployed in Macao where non-fossil electricity is relatively abundant, BEB can significantly reduce WTW emissions of nitrogen oxides (NO X ) and volatile organic compounds (VOC) by 60%–80%, along with considerable reductions of 10%–40% for CO 2 and fine particulate matters (PM 2.5 ). Further, the benefits related to WTW CO 2 and PM 2.5 emissions would not exist if BEBs are deployed in coal power-rich regions. Our measurement results and WTW emission suggests that current fuel economy testing procedure of BEB should be modified to better inform customers and policy-makers of their real-world performance and benefits.

[1]  A. Pesaran,et al.  Addressing the Impact of Temperature Extremes on Large Format Li-Ion Batteries for Vehicle Applications (Presentation) , 2013 .

[2]  Yu Zhou,et al.  Real-world fuel consumption and CO2 (carbon dioxide) emissions by driving conditions for light-duty passenger vehicles in China , 2014 .

[3]  Subash Dhar,et al.  Electric vehicles and India's low carbon passenger transport: A long-term co-benefits assessment , 2017 .

[4]  J. Hao,et al.  Assessment of vehicle emission programs in China during 1998-2013: Achievement, challenges and implications. , 2016, Environmental pollution.

[5]  Paulina Jaramillo,et al.  Life cycle ownership cost and environmental externality of alternative fuel options for transit buses , 2017 .

[6]  Jiming Hao,et al.  On-road vehicle emissions and their control in China: A review and outlook. , 2017, The Science of the total environment.

[7]  Wei Shen,et al.  Individual trip chain distributions for passenger cars: Implications for market acceptance of battery electric vehicles and energy consumption by plug-in hybrid electric vehicles , 2016 .

[8]  H Christopher Frey,et al.  Method for in-use measurement and evaluation of the activity, fuel use, electricity use, and emissions of a plug-in hybrid diesel-electric school bus. , 2010, Environmental science & technology.

[9]  Timothy E. Lipman,et al.  Lifecycle cost assessment and carbon dioxide emissions of diesel, natural gas, hybrid electric, fuel cell hybrid and electric transit buses , 2016 .

[10]  Wenwei Ke,et al.  Can propulsion and fuel diversity for the bus fleet achieve the win–win strategy of energy conservation and environmental protection? , 2015 .

[11]  Shaojun Zhang,et al.  Real-world fuel consumption and CO2 emissions of urban public buses in Beijing , 2014 .

[12]  J. Hao,et al.  High-resolution simulation of link-level vehicle emissions andconcentrations for air pollutants in a traffic-populated eastern Asian city , 2016 .

[13]  Yong Geng,et al.  Inter-city passenger transport in larger urban agglomeration area: emissions and health impacts , 2016 .

[14]  Jing-Quan Li,et al.  Battery-electric transit bus developments and operations: A review , 2016 .

[15]  Yu Zhou,et al.  Can Euro V heavy-duty diesel engines, diesel hybrid and alternative fuel technologies mitigate NOX emissions? New evidence from on-road tests of buses in China , 2014 .

[16]  Wei Shen,et al.  Current and future greenhouse gas emissions associated with electricity generation in China: implications for electric vehicles. , 2014, Environmental science & technology.

[17]  Wenwei Ke,et al.  Real-world performance of battery electric buses and their life-cycle benefits with respect to energy consumption and carbon dioxide emissions , 2016 .

[18]  Haibo Zhai,et al.  Comparing real-world fuel consumption for diesel- and hydrogen-fueled transit buses and implication for emissions , 2007 .

[19]  Nick Molden,et al.  Engine maps of fuel use and emissions from transient driving cycles , 2016 .

[20]  Randall Guensler,et al.  Assessment of alternative fuel and powertrain transit bus options using real-world operations data: Life-cycle fuel and emissions modeling , 2015 .

[21]  Yu Zhou,et al.  Historic and future trends of vehicle emissions in Beijing, 1998–2020: A policy assessment for the most stringent vehicle emission control program in China , 2014 .

[22]  Shuxiao Wang,et al.  Assessing the Future Vehicle Fleet Electrification: The Impacts on Regional and Urban Air Quality. , 2017, Environmental science & technology.

[23]  Bao-Jun Tang,et al.  The analysis of the battery electric vehicle’s potentiality of environmental effect: A case study of Beijing from 2016 to 2020 , 2017 .

[24]  Robert Prohaska,et al.  Foothill Transit Battery Electric Bus Demonstration Results , 2016 .

[25]  Paulina Jaramillo,et al.  Comparison of life cycle greenhouse gases from natural gas pathways for medium and heavy-duty vehicles. , 2015, Environmental science & technology.

[26]  Wenwei Ke,et al.  Well-to-wheels energy consumption and emissions of electric vehicles: Mid-term implications from real-world features and air pollution control progress , 2017 .

[27]  Hewu Wang,et al.  Levelized costs of conventional and battery electric vehicles in china: Beijing experiences , 2015, Mitigation and Adaptation Strategies for Global Change.

[28]  Ye Wu,et al.  Energy consumption and CO2 emission impacts of vehicle electrification in three developed regions of China , 2012 .

[29]  Egoitz Martinez-Laserna,et al.  Sustainability analysis of the electric vehicle use in Europe for CO2 emissions reduction , 2016 .

[30]  Yu Zhou,et al.  The challenge to NO x emission control for heavy-duty diesel vehicles in China , 2012 .

[31]  Eckard Helmers,et al.  Electric car life cycle assessment based on real-world mileage and the electric conversion scenario , 2015, The International Journal of Life Cycle Assessment.

[32]  Michael Q. Wang,et al.  New energy vehicles in China: policies, demonstration, and progress , 2012, Mitigation and Adaptation Strategies for Global Change.

[33]  Yu Zhou,et al.  Real-world emissions and fuel consumption of diesel buses and trucks in Macao: From on-road measurement to policy implications , 2015 .