Light-duty Passenger Vehicles Research Articles

Light-duty passenger vehicle electrification in China from 2021 to 2050 and associated greenhouse gas emissions: A dynamic fleet perspective

The electric vehicle is seen as a promising technology to decarbonize road transportation. However, the long-term and fleet-scale impacts of the electric vehicle promotion in China are still underexplored. To investigate the mitigation potential of light-duty passenger vehicles electrification, a dynamic fleet-based life cycle assessment framework is constructed to calculate the annual greenhouse gas (GHG) emissions in China from 2021 to 2050. It is estimated that the annual fleet GHG emissions will peak at 1.10 ∼ 1.18 Gt between 2028 and 2031, and gradually decrease to 0.53 ∼ 1.04 Gt CO2 eq in 2050. Under the most sustainable pathway (SSP1), the aggressive electrification scenario (SSP1-EV2040) is projected to reduce accumulative life cycle GHG emissions by 5.4Gt CO2 eq (17 % of the accumulative emissions in SSP2-BAU). The regional distribution of GHG emissions and electricity use shows a downward trend from east to west, revealing the necessity of China’s regional-specified strategy..

Greenhouse gas emissions benefits of the lightweight vehicle fleet in China: A dynamic fleet perspective

Lightweighting is believed to be a silver bullet to reduce greenhouse gas (GHG) emissions related to the road transportation. However, the fleet-scale and long-term GHG emissions estimation on the light-duty passenger vehicle (LDPV) fleet in China is still underexplored. A dynamic fleet-based life cycle assessment (LCA) model is developed to predict the annual GHG emissions attributable to the lightweight LDPV fleet in China at provincial level. With the most aggressive implementation of lightweighting, the cumulative mitigation potential of lightweight LDPV fleet from 2021 to 2050 is 0.72 Gt CO2 eq and 0.55 Gt CO2 eq using high-strength steel (AHSS) and aluminium (Al), respectively. Sooner implementation brings a higher cumulative reduction in GHG emissions. Delaying the implementation by five years would sacrifice 0.16 Gt CO2 eq ∼0.2 Gt CO2 eq cumulative reduction, and the loss would increase to 0.31 Gt CO2 eq ∼0.41 Gt CO2 eq when postpone the lightweighting by ten years.

Estimation and Analysis of Air Pollutant Emissions from On-Road Vehicles in Changzhou, China

Vehicle emissions have become a significant contributor to urban air pollution. However, studies specific to city-level vehicle emission inventories are still scarce and tend to be outdated. This study introduces a methodology for developing high-resolution monthly vehicle emission inventories. We applied this methodology to Changzhou in 2022 to analyze emission characteristics and generate gridded emission data with a resolution of 0.01° × 0.01°. The results show that the total vehicle emissions of carbon monoxide (CO), volatile organic compounds (VOCs), nitrogen oxides (NOx), and fine particulate matters (PM2.5) in Changzhou are 39.69, 8.68, 18.6, and 0.56 Gg, respectively. Light-duty passenger vehicles are the main contributors to CO (74.3%) and VOCs (86.1%) emissions, while heavy-duty trucks play a significant role in NOx (50.7%) and PM2.5 (34.7%) emissions. Gasoline vehicles are mainly responsible for CO (78.6%) and VOCs (91.4%) emissions, while diesel vehicles are the primary source of NOx (81.1%) and PM2.5 (70.6%) emissions. Notably, China IV vehicles have the highest emission contribution rates (ranging from 32.5% to 44.9%). Seasonally, emissions peak in winter and are lowest in April. Spatially, emission intensity is higher in the northeast of Changzhou compared to the west and south. The methodology presented in this study offers a valuable tool for developing comprehensive city-level emission inventories, and the results provide critical insights that can inform the formulation of effective environmental policies.

Growth in the Worldwide Stock of E-Mobility Vehicles (by Technology and by Transport Mode) and the Worldwide Stock of Hydrogen Refueling Stations and Electric Charging Points between 2020 and 2022

This study discusses the portion of fuel cell electric vehicles (FCEVs) in the worldwide stock of vehicles on roads, particularly when compared to plug-in electric vehicles (PEVs), which comprise battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs). The study considers the overall number of these e-mobility (electric mobility) vehicles, as well as within each of 4 transport modes, namely: (1) passenger light-duty vehicles (PLDVs or simply “cars”), (2) light commercial vehicles (LCVs or simply “vans”), (3) buses, and (4) trucks. The study also investigates the progress in the number of hydrogen refueling stations (HRSs) for FCEVs, and contrasts that with electric charging points (ECPs) for PEVs; during the years 2020, 2021, and 2022. While the number of worldwide FCEVs nearly doubled in 2022 compared to 2020, the ratio of FCEVs to PEVs declined from 0.3348% in 2020 to 0.2738% (less than 0.3%) in 2022. In 2022 also, the number of FCEVs was 0.3914% (less than 0.4%) of the number of BEVs, and 0.9113% (less than 1%) of the number of PHEVs. The worldwide fraction of PEVs with respect to the total vehicles (both electric and non-electric) in 2022 was approximately 1.816% (split into 1.2704% for BEVs and 0.5456% for PHEVs), while the fraction of FCEVs was approximately 0.0050% (only 5 FCEVs per 100,000 vehicles). In terms of the convenience to supply the vehicles with energy, the number of worldwide hydrogen refueling stations nearly doubled in 2022 compared to 2020. Similarly, the worldwide number of electric charging points for use with PEVs nearly doubled in 2022 compared to 2020. However, the ratio of HRSs to ECPs declined from 0.0415% in 2020 to 0.0378% in 2022. The worldwide average FCEVs per HRS in 2022 was 70.69, while the worldwide average PEVs per ECP in 2022 was 9.75. Thus, PEVs are much more attractive than FCEVs for a driver concerned about the network of hydrogen stations. Furthermore, owners of PEVs have an additional option of recharging their vehicles at home (which is not applicable for FCEVs). Between 2020 and 2022, PEVs were dominated by BEVs, with 69.95% of PEVs being BEVs in 2022. This 2022 fraction of BEVs in PEVs reflects a consistent increase from the 2021 fraction (68.34%) and from the 2020 fraction (67.23%). Considering the worldwide increase in these e-mobility vehicles from 2020 to 2022, the number of FCEVs increased by a factor of 2.072, PHEVs increased by a factor of 2.322, and BEVs increased by a factor of 2.636, PEVs increased by a factor of 2.533. Thus, out of the 3 e-mobility vehicle technologies (FCEVs, PHEVs, and BEVs), BEVs had the strongest presence as well as the fastest growth.

The Impact of Mesopores of SnO2 Catalyst Support on the Performance of Polymer Electrolyte Fuel Cells

Recently, the focus of future polymer electrolyte fuel cell (PEFC) application for automobiles has shifted from the class of passenger light-duty vehicles (LDVs) to that of heavy-duty vehicles (HDVs). The total operating time in the lifetime of HDVs is much longer than that of LDVs. Thus, durability is becoming more and more important for the cell components including the catalyst materials, and the compatibility between initial performance and durability at a high level is desired. Employing mesoporous carbons as catalyst supports is a promising option to enhance the initial performance [1]. In the catalyst layer of a PEFC with mesoporous carbon support, Pt-based catalyst nanoparticles deposited inside the mesopores are not directly covered by ionomer. As a result, a catalyst poisoning by sulfonic acid groups of the ionomer is hindered and a high catalytic activity is obtained. In addition, a high oxygen transport resistance thorough Pt/ionomer interfaces [2] can be mitigated by employing mesoporous carbon support. Nonetheless, from the viewpoint of thermodynamics, carbon support can oxidatively degrade during the long-term operation. Tin oxide (SnO2) is one of the promising candidates for substituting the carbon support because of its high electrochemical stability at high potentials [3]. However, to our best knowledge, the mitigation of the ionomer adsorption on the Pt surface by using mesoporous SnO2 support has not been studied in previous works. In this study, we synthesized mesoporous SnO2 supports and investigated the impact of the mesopore on the performance of the PEFC. Connected mesoporous Sb-doped SnO2 particles (CMSbTOs) were synthesized by using a mesoporous carbon as a template (Figure (a)). The size of the mesopore was successfully controlled in the range of 4 – 10 nm by adjusting the carbon template structure and calcination temperature (Figure (b)). The BET surface area and conductivity of the CMSbTOs were in the ranges of 90 – 210 m2 g-1 and ca. 10-2 S cm-1, respectively. Pt nanoparticles were deposited on the CMSbTOs via a colloidal method to obtain Pt/CMSbTO catalyst (Pt loading of 20 wt.%). It was confirmed that the Pt nanoparticles were located both on the outer surface and inside the mesopores of the CMSbTOs by scanning transmission electron microscopy-energy dispersive spectroscopy (TEM-EDS) analysis. A membrane electrode assembly (MEA) was fabricated by using a Pt/CMSbTO catalyst for the cathode catalyst layer and single cell tests were performed under dried (30%RH, 82 °C) and highly humidified (80%RH, 60 °C) conditions. In addition, a homemade Pt/Sb-SnO2 catalyst with solid-core SnO2 support and a commercial Pt/Vulcan catalyst (TEC10V30E, TKK) were also tested for comparison. Under the dried conditions, the Pt/CMSbTO catalyst showed a better I-V performance than the Pt/Sb-SnO2 (solid) catalyst and Pt/Vulcan catalyst (Figure (c)). The oxygen reduction reaction (ORR) activity of the Pt/CMSbTO catalyst at 0.84 V was higher than that of the Pt/Sb-SnO2 (solid) and Pt/Vulcan catalysts. This result suggests that catalyst poisoning by the ionomer is mitigated when the mesoporous SnO2 support is employed. Moreover, the local oxygen transport resistance (oxygen transport resistance that is independent of the total gas pressure) of the Pt/CMSbTO catalyst was lower than that of the Pt/Sb-SnO2 (solid) and Pt/Vulcan catalysts, probably because of a decrease in the oxygen transport resistance due to Pt/ionomer interfaces. In contrast, under the highly humidified conditions, the I-V performance of the Pt/CMSbTO catalyst was comparable to that of the Pt/Sb-SnO2 (solid) catalyst and slightly lower than that of the Pt/Vulcan catalyst (Figure (d)). This result can be ascribed to floodings inside the mesopores of the CMSbTO support. Accelerated stress tests (repeated potential steps between 1.0 – 1.5 V under 100%RH, 80 °C) were also performed to confirm the electrochemical stability of the Pt/CMSbTO catalyst at high potentials. The Pt/CMSbTO catalyst showed a much higher retention rate of the electrochemical Pt surface area (ECSA) than the Pt/Vulcan catalyst as expected. More details, including the effect of the pore size of the CMSbTO support on the initial performance, will be discussed in the presentation.

Co-drivers of Air Pollutant and CO2 Emissions from On-Road Transportation in China 2010-2020.

Co-controlling the emissions of air pollutants and CO2 from automobiles is crucial for addressing the intertwined challenges of air pollution and climate change in China. Here, we analyze the synergetic characteristics of air pollutant and CO2 emissions from China's on-road transportation and identify the co-drivers influencing these trends. Using detailed emission inventories and employing index decomposition analysis, we found that despite notable progress in pollution control, minimizing on-road CO2 emissions remains a formidable task. Over 2010-2020, the estimated sectoral emissions of VOCs, NOx, PM2.5, and CO declined by 49.9%, 25.9%, 75.2%, and 63.5%, respectively, while CO2 emissions increased by 46.1%. Light-duty passenger vehicles and heavy-duty trucks have been identified as the primary contributors to carbon-pollution co-emissions, highlighting the need for tailored policies. The driver analysis indicates that socioeconomic changes are primary drivers of emission growth, while policy controls, particularly advances in emission efficiency, can facilitate co-reductions. Regional disparities emphasize the need for policy refinement, including reducing dependency on fuel vehicles in the passenger subsector and prioritizing co-reduction strategies in high-emission provinces in the freight subsector. Overall, our study confirms the effectiveness of China's on-road control policies and provides valuable insights for future policy makers in China and other similarly positioned developing countries.

FMVSS 141 for Commercial Vehicles: Applicability and Limitations

Newly manufactured light-duty hybrid and electric passenger vehicles must comply with FMVSS 141 minimum sound requirements to reduce the risk of crashes with visually impaired and inattentive pedestrians. Commercial vehicles operate in a variety of noise-critical environments, from densely packed industrial yards to congested urban areas, making safe electric vehicle operation around pedestrians and bystanders vital. Though the market share of medium and heavy-duty hybrid and electric vehicles is projected to increase annually, there are currently no North American regulations specifically for minimum sound emissions of hybrid and electric vehicles heavier than 10,000 lb. GVWR. The primary intent of this paper is to investigate the efficacy and limitations of the current FMVSS 141 requirements when applied to heavy-duty electric trucks. Serving as a complementary test case, a Class 8 Freightliner eCascadia electric truck with onboard Acoustic Vehicle Alerting System (AVAS) was evaluated at Daimler Truck North America's High Desert Proving Grounds in accordance with the FMVSS 141 procedure for light-duty passenger vehicles. Analysis of the measured data found the FMVSS 141 forward gear criteria to be reasonably effective when applied to the test vehicle, but the standard's reverse gear criteria were deficient to other common industry-accepted backing alert methods. These results are used as a starting point for a discussion on various aspects of FMVSS 141, with an emphasis on how adding commercial vehicles to the scope of the standard could necessitate further changes to the defined acceptance criteria.

Emissions of multiple metals from vehicular brake linings wear in China, 1980–2020

Metals emitted from brake linings wear have adverse effects on air quality and human health due to their toxicity and reactivity. However, complexities of factors affecting brake like conditions of vehicles and roads hinder the accurate quantification. Here, we established a comprehensive emission inventory for multi-metals from brake linings wear in China during 1980–2020, based on metals contents in well-representative samples, the wear of brake linings before replacement, vehicle populations, fleet composition, and vehicle-kilometers travelled (VKT). We show that with the boom of vehicle population, the total emissions of studied metals have surged from 3.7 × 106 g in 1980 to 4.9 × 1010 g in 2020, which mainly concentrated in coastal and eastern urban areas while grown significantly in the central and western urban areas in recent years. Therein, Ca, Fe, Mg, Al, Cu, and Ba were the top six metals emitted, together responsible for >94 % of the mass total. Jointly determined by brake linings especially metals contents thereof, VKTs, and vehicle populations, heavy-duty trucks, light-duty passenger vehicles, and heavy-duty passenger vehicles were the top three contributors in metals emissions, together accounting about 90 % of the total. Moreover, more precise description on real-world metals emissions from brake linings wear are still urgently needed, considering the increasingly significant role it has been playing on worsening air quality and public health.

Evolution and Characteristics of Full-process Vehicular VOCs Emissions in Tianjin from 2000 to 2020

Vehicle emissions are an important source of anthropogenic volatile organic compound (VOCs) emissions in urban areas and are commonly quantified using vehicle emission inventories. However, most previous studies on vehicle emission inventories have incomplete emission factors and emission processes or insufficient consideration of meteorological parameters. Based on the localized full-process emission factors attained from tested data and previous studies, a method to develop a monthly vehicular VOC emission inventory of full process for the long-term was established, which covered exhaust and evaporative emissions (including running loss, diurnal breathing loss, hot soak loss, and refueling emission). Then, the method was used to develop a full-process vehicular VOC emission inventory in Tianjin from 2000 to 2020. The results showed that the total vehicular VOC emissions in Tianjin rose slowly and then gradually decreased. In 2020, the total emissions were 21400 tons. The light-duty passenger vehicles were the dominant contributors and covered 75.00% of the total emissions. Unlike the continuous decline in exhaust emissions, evaporative emissions showed an inverted U-shaped trend with an increasing contribution to total emissions yearly, accounting for 31.69% in 2020. Monthly emissions were affected by both vehicle activity and emission factors. VOC emissions were high in autumn and winter and low in spring and summer. During the COVID-19 epidemic in 2020, vehicle activity was limited by closure and control, making VOC emissions significantly lower than those during the same period in previous years. The method and data in this study can provide technical reference and a decision-making basis for air pollution prevention and control.

Comparative Analysis of Emission Characteristics of In-Use China II–V Gasoline, Hybrid, Diesel-Fueled Vehicles

Increasingly stringent regulations regarding vehicle emissions have contributed to the diversification of vehicle technologies, resulting in the increasing complexity of typical vehicles that make up a fleet. In order to investigate the real gas emissions of different typical vehicles, tests were conducted using a portable emission measurement system (PEMS) in Beijing and emission studies were conducted on eight light-duty passenger vehicles (LDPVs, including light-duty gasoline passenger vehicles and hybrid electric vehicles), eight heavy-duty passenger vehicles (HDPVs), and four light-duty trucks (LDTs). The results show that the emissions of relevant pollutants from LDPV meet the emission standard limits. The emission factors of CO2, CO, NOX, and HC of China IV and China V hybrid electric vehicles (HEVs) are much smaller than the emission standard limits and the emission factors of other vehicles, which have better emission reduction effects. Among LDPV, heavy-duty passenger vehicles (HDPVs), and LDT, the emissions of HDPV and LDT are extremely high. Emission characteristics vary on different types of roads, with the highest emission factors generally occurring on secondary roads. The micro-trip method was used to explore the influence of speed on emission factors. HEV are less sensitive to speed changes and can still maintain a low emission level at low speeds. The average speed and emission factors of HDPV in micro-trip has a strong correlation.

Electrified autonomous freight benefit analysis on fleet, infrastructure and grid leveraging Grid-Electrified Mobility (GEM) model

Fast-growing freight activities over the decades have become one of the major contributors to air pollution, leading to many efforts in freight decarbonization and electrification. However, the development of freight electrification is slow due to technological uncertainty, slow charging, high capital cost, etc. This paper analyzes the potential impact and benefit of heavy-duty vehicle (HDV) electrification and automation on fleet cost, infrastructure cost, the electricity grid, and environmental outcomes. In this work, we extended the vehicle electrification benefit analysis tool: Grid-Electrified Mobility (GEM) model, which had primarily been used to study light-duty passenger vehicles (LDVs), to analyze heavy-duty vehicle electrification. The extended model is derived for freight transportation electrification, and different freight electrification and automation adoption scenarios were analyzed. We find that the increased penetration of automated electric freight fleets within other types of electrified freight fleets from 1% to 99% will result in an overall cost reduction of 18.2%, fleet size reduction of 20.4%, and lower peak load reduction of 14.3%.

The Characteristics of Light-Duty Passenger Vehicle Mileage and Impact Analysis in China from a Big Data Perspective

Vehicle mileage is one of the key parameters for accurately evaluating vehicle emissions and energy consumption. With the support of the national annual vehicle emission inspection networked platform in China, this study used big data methods to analyze the activity level characteristics of the light-duty passenger vehicle fleet with the highest ownership proportion. We found that the annual mileage of vehicles does not decay significantly with the increase in vehicle age, and the mileage of vehicles is relatively low in the first few years due to the run-in period, among other reasons. This study indicated that the average mileage of the private passenger car fleet is 10,300 km/yr and that of the taxi fleet was 80,000 km/yr in China in 2019, and the annual mileage dropped by 22% in 2020 due to the pandemic. Based on the vehicle mileage characteristics, the emission inventory of major pollutants from light-duty passenger vehicles in China for 2010–2020 was able to be updated, which will provide important data support for more accurate environmental and climate benefit assessments in the future.

Understanding the Impact of Microporous Layer Cracks on Pt Catalyst Degradation

As the need for more flexible utilization of renewable energy sources increases, the uses of clean hydrogen and fuel cells are pursued by governments worldwide due to high gravimetric energy density of hydrogen. Polymer electrolyte fuel cells (PEFCs) have demonstrated great potential in passenger light-duty vehicles (LDVs), and their applications in heavy-duty vehicles (HDVs) have recently attracted significant attention due to their unique scalability1. Currently, the micro porous layer (MPL), the side of the gas diffusion layer that faces the catalyst layer in the membrane electrode assembly (MEA), is known to improve the performance of PEFCs at high current densities due to better heat, water management, and electron transport. And there has been an ongoing debate whether changes in water management through having cracks in the MPL will improve the durability of the catalyst. Cracks in the MPL are advantageous as they can facilitate removal of liquid water from the catalyst layer. However, too many cracks can result in poor contact between the MPL and the MEA2. Cracks can also pool water and block oxygen transport.In this study, electrocatalyst accelerated stress tests (ASTs) were performed on the MEAs prepared using MPLs with different density and configuration of cracks. The ASTs had a total of 90 000 cycles, with electrochemical characterization performed at beginning of life, after 10 000, 30 000, 60 000 and 90 000 (end of life). Each cycle consisted of potential cycling between 0.6 V to 0.9 V, with 3 seconds hold time for each. The effect of cracks in MPLs on electrocatalyst degradation was evaluated in both nitrogen (non-reactive) and air (reactive) gas environments at 100% relative humidity, 80oC, and 150 kPa backpressure. In-situ electrochemical characterization and extensive physical characterization was performed to understand the subtle differences in electrocatalyst degradation correlated to the use of crack-free and cracked MPLs. In particular, micro-X-ray fluorescence (XRF) map of identical locations before and after the AST were employed to study in-plane movement of Pt loading over the course of AST. Micro x-ray diffraction (XRD) maps were collected on the MEAs to correlate Pt loadings to Pt particle size distribution.The polarization curves, Tafel plots, and electrochemical surface area (ECSA) for MEAs with and without cracks in the MPLs all demonstrated similar trends in the cells’ durability, revealing that cracks in the MPLs do not significantly affect the performance of the cell at the beginning and also at the end of life. However, the XRF identical location maps showed significant in-plane movement of Pt over the course of the AST: decrease of Pt loading in the mapped region closer to the gas inlet and increase of Pt loading closer to the gas outlet. Moreover, higher degree of cracking was observed at the cell outlet after the AST, indicating that the catalyst layer mechanical aging is not homogeneous.

Highly spatial and temporal bottom-up vehicle emission characterization and its control in a typical ecology-preservation area

The Chishui River Valley is a microscale ecology-preservation area with industrial clusters. The significance of evaluating vehicular emissions has been gradually highlighted with the rapid development of the local transportation and tourism sectors. This study provides the first estimates based on both bottom-up and top-down approaches. The annual total emissions of CO, NO x , hydrocarbons (HC), PM 10, and PM 2.5 in 2019 were 347.8, 189.6, 46.3, 6.9, and 6.3 Mg, respectively. Trucks contributed the most (55%) to the NO x emissions, followed by heavy-duty passenger vehicles (26%). In contrast, light-duty passenger vehicles and motorcycles generated 75% of the HC emissions. The superior accuracy of highly spatial and temporal bottom-up estimates versus top-down estimates is validated by the similar variation trends of hourly emission intensities and enhanced concentrations relative to background observations for both NO x and CO, with Pearson correlation coefficients between the intensities and concentrations ranging from 0.79 to 0.85. Historical HC emissions peaked in 2013, followed by a sharp decline in 2014 and a continuous rise since then, whereas NO x emissions have kept increasing since 2010. These indicated the necessity and urgency of effective vehicular emission mitigations. Based on scenario analysis, traffic restrictions combined with upgrading the emission standards of admitted vehicles will possess huge emission reduction potentials. Future recommendations about establishing a low emission zone in the valley and supporting policies were introduced. • On-road vehicle bottom-up emission intensity (EI) was built with a spatial resolution of 10 m × 10 m. • Temporal variations of bottom-up EI showed strong relationship with observations. • Bottom-up EI with traffic-flow data showed superiority to top-down estimate. • Traffic-restriction with stringent standards led to huge emission reduction benefits. • A low emission zone (LEZ) is proposed for a microscale area possessing ecology-preservation nature.

The impacts from cold start and road grade on real-world emissions and fuel consumption of gasoline, diesel and hybrid-electric light-duty passenger vehicles

Progressively stringent regulations regarding vehicle emissions and fuel economy have spurred technology diversification in light-duty passenger vehicles (LDPVs). To assess the real-world emissions and fuel economy performances of hybrid electric vehicles (HEVs) compared to conventional internal combustion engine (ICE) vehicles, on-road measurements of ten gasoline, four diesel and six full hybrid LDPVs were performed using portable emissions measurement systems (PEMS) in Macao, China. The hot-running emission results indicate that the high emission risks of gasoline vehicles are associated with high mileage and old model years. Diesel vehicles are found to be the highest pollutant emitters in this study due to the intentional removal of aftertreatment systems. Under hot-running conditions, HEVs, as expected, could achieve carbon-reduction benefits of approximately 30 % (i.e., lower CO2 emissions and fuel consumption) compared to their conventional gasoline counterparts, while no measurable reduction in pollutant emissions was observed except in NOX (~70 % reduction). In contrast, the cold-start extra emissions (CSEEs) of CO2 reached 120–364 g/start for these HEVs, even exceeding the maximum values of conventional gasoline vehicles. However, the higher CO2 CSEEs of HEVs can be far offset by their hot-running emission reduction benefits. For tailpipe pollutants, the CSEEs of the HEVs were reduced by 21 %–68 % on average in comparison to those of conventional gasoline vehicles. Furthermore, strong correlations (R2 values of 0.69–0.89) between the road grades and relative emissions were observed. These results can provide necessary information regarding the improvement of future LDPV emission models and inventories.

Measurement-based intermediate volatility organic compound emission inventory from on-road vehicle exhaust in China

Intermediate volatility organic compounds (IVOCs) have great potential to form secondary organic aerosols (SOA) in the atmosphere. Thus, a high-resolution IVOC emission inventory is essential for the accurate simulation of SOA formation. This study developed the first nationwide on-road vehicular IVOC emission inventory in China based on localized measurement of the IVOC emission factors and volatility distributions for various vehicle types. The total vehicular IVOC emissions in China in 2019 were estimated to be 241.2 Gg. Heavy-duty trucks, light-duty trucks, and light-duty passenger vehicles contributed the most, accounting for 47.6%, 24.6%, and 16.9% of total vehicular IVOC emissions, respectively. Although much higher in number, gasoline vehicles contributed 15.0%, which was far less than the contribution of diesel vehicles. The two peaks in volatility bins B12–B13 and B16–B17 accounted for 42.2% and 23.7% of the total IVOC emissions, respectively. By gridding the emission inventory into a relatively high resolution of 0.1° × 0.1°, high-emission areas and hotspots were clearly identified. In general, eastern China had substantially higher vehicular IVOC emissions than western China. High-emission areas with emission intensity >10 Mg·grid−1 covered most of the North China Plain, Yangtze River Delta, and Pearl River Delta. The emission intensity over the downtown areas of Beijing and Shanghai exceeded 50 Mg·grid−1. In contrast, IVOC emissions over western China were relatively lower, with a network structure gathering around the traffic arteries serving inter-provincial transportation. This study underscored the importance of having a localized emission factor to better reflect the IVOC emission characteristics from Chinese vehicles and to improve the assessment of their environmental impacts.

Smart charging strategies for heavy electric vehicles

With emission standards tightening around the world and the popularity of electric cars rising, the electrification of heavy-duty vehicles (e.g., diesel trucks) appears to be a natural progression. For electric truck (ET) charging, a return-to-base strategy with chargers located where trucks begin and end each day, such as trucks used in cargo, freight, and delivery entities, is becoming increasingly viable and attractive. This return-to-base strategy; however, has impacts on the peak demand of a facility which can contribute to an increase in demand charge and requires electrical asset upgrades in certain circumstances. This challenge is different and unique compared to the light-duty passenger vehicles charging challenge (i.e., low distributed charging load and longer charging periods). To address this ET charging challenge, this paper proposes a smart charging system (SCS) that manages the charging process of ETs at their commercial facilities, with the objective of minimizing the peak demand of the aggregate load profile at the facility. Our simulation studies show the effectiveness of the proposed SCS in reducing the peak demand of the facility. The proposed solution can achieve a monthly saving in demand charge of up to 54% compared to uncontrolled charging schemes. • A smart charging system to address the challenges of ET charging at their facilities. • Addresses ET operators' concerns over the increase of demand charges of ET charging. • Accommodates the V2V and V2G technologies in the smart charging system of ETs. • Increases the adoption rate of electric trucks into the different commercial fleets. • The proposed solution can achieve a monthly saving in demand charge of up to 54%.

Decarbonisation of passenger light-duty vehicles using spatially resolved TIMES-Ireland Model

Higher spatial resolution is becoming a key component of energy system analysis. Existing multi-regional national scale energy systems optimisation models (ESOMs) facilitate an improved understanding of spatial dynamics. Yet, region-specific characteristics of transport technologies and infrastructures along with consumer heterogeneity have remained under-investigated. The current paper addresses this gap by developing a multi-regional transport sector within the system-wide TIMES-Ireland Model (TIM). The transport sector is divided into 26 sub-regions, and each region is characterised by the existing vehicle fleet, public transport availability, scrappage rate, annual mileage, vehicle fuel economy and the corresponding passenger and freight mobility demand. The consumers (car buyers) are disaggregated based on their income level to incorporate a more realistic representation of their behaviour in vehicle purchasing decisions. While TIM ensures carbon neutrality across the whole energy system by mid-century, this study mainly explores the decarbonisation of passenger Light-Duty Vehicles (LDVs). It shows to what extent different measures (i.e, LDV improvements, monetary incentives, modal shift, biofuel obligation, carbon tax and occupancy rate) can contribute to meeting ambitious mitigation targets by 2030. Spatially resolved analysis as the main novelty of this research presents valuable insights into regional electric vehicles (EVs) diffusion and their electricity consumption. The proposed method can be used to address the uncertainty that arises from consumer heterogeneity in the policymaking process. The findings also suggest keeping financial EV incentives until the mid-2020s to meet the ambitious goals. Finally, decarbonisation without demand-side strategies (i.e., controlling the level of private-car-based mobility) seems to be unachievable.

Analysis of the Li-ion battery industry in light of the global transition to electric passenger light duty vehicles until 2050

Abstract The decarbonization of the transport sector requires a rapid expansion of global battery production and an adequate supply with raw materials currently produced in small volumes. We investigate whether battery production can be a bottleneck in the expansion of electric vehicles and specify the investment in capital and skills required to manage the transition. This may require a battery production rate in the range of 4–12 TWh/year, which entails the use of 19–50 Mt/year of materials. Strengthening the battery value chain requires a global effort in many sectors of the economy that will need to grow according to the battery demand, to avoid bottlenecks along the supply chains. Significant investment for the establishment of production facilities (150–300 billion USD in the next 30 years) and the employment of a large global workforce (400k–1 million) with specific knowledge and skillset are essential. However, the employment and investment required are uncertain given the relatively early development stage of the sector, the continuous advancements in the technology and the wide range of possible future demand. Finally, the deployment of novel battery technologies that are still in the development stage could reduce the demand for critical raw materials and require the partial or total redesign of production and recycling facilities affecting the investment needed for each factory.

High-resolution mapping of regional traffic emissions using land-use machine learning models

Abstract. On-road vehicle emissions are a major contributor to significant atmospheric pollution in populous metropolitan areas. We developed an hourly link-level emissions inventory of vehicular pollutants using two land-use machine learning methods based on road traffic monitoring datasets in the Beijing–Tianjin–Hebei (BTH) region. The results indicate that a land-use random forest (LURF) model is more capable of predicting traffic profiles than other machine learning models on most occasions in this study. The inventories under three different traffic scenarios depict a significant temporal and spatial variability in vehicle emissions. NOx, fine particulate matter (PM2.5), and black carbon (BC) emissions from heavy-duty trucks (HDTs) generally have a higher emission intensity on the highways connecting to regional ports. The model found a general reduction in light-duty passenger vehicles when traffic restrictions were implemented but a much more spatially heterogeneous impact on HDTs, with some road links experiencing up to 40 % increases in the HDT traffic volume. This study demonstrates the power of machine learning approaches to generate data-driven and high-resolution emission inventories, thereby providing a platform to realize the near-real-time process of establishing high-resolution vehicle emission inventories for policy makers to engage in sophisticated traffic management.