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Province-Level Decarbonization Potentials for China’s Road Transportation Sector
... For example, data from the CEMS is potential to track emissions from power and industry subsectors at the facility level [42][43][44] . And large-scale inspection data can provide more insights about real-world activities and fuel consumption of single vehicle 45 . ...
The electrification of trucks is a major challenge in achieving zero-emission transportation. Here we gathered year-long records from 61,598 electric trucks in China. Current electric trucks were found to be significantly underutilized compared with their diesel counterparts. Twenty-three per cent of electric delivery trucks and 30% of semi-trailers could achieve one-on-one replacement with diesel counterparts, while on average 3.8 electric delivery trucks and 3.6 electric semi-trailers are required to match the transportation demand that is served by one diesel truck separately. For diesel trucks that are capable of one-on-one replacement, electric trucks have 15–54% and 1–49% reductions in cost and life-cycle CO2 emissions, respectively. Enhancements in usage patterns, vehicle technologies and charging infrastructure can improve electrification feasibility, yielding cost and decarbonization benefits. Increased battery energy densities with optimized usage can make one-on-one electrification feasible for more than 85% of diesel semi-trailers. In addition, with cleaner electricity, most Chinese electric trucks in 2030 will have lower expected life-cycle CO2 emissions than diesel trucks.
Passenger and freight travel account for 28% of U.S. greenhouse gas (GHG) emissions today. We explore pathways to reduce transportation emissions using NREL’s TEMPO model under bounding assumptions on future travel behavior, technology advancement, and policies. Results show diverse routes to 80% or more well-to-wheel GHG reductions by 2050. Rapid adoption of zero-emission vehicles coupled with a clean electric grid is essential for deep decarbonization; in the median scenario, zero-emission vehicle sales reach 89% for passenger light-duty and 69% for freight trucks by 2030 and 100% sales for both by 2040. Up to 3,000 terawatt-hours of electricity could be needed in 2050 to power plug-in electric vehicles. Increased sustainable biofuel usage is also essential for decarbonizing aviation (10–42 billion gallons needed in 2050) and to support legacy vehicles during the transition. Managing travel demand growth can ease this transition by reducing the need for clean electricity and sustainable fuels.
Vehicle emissions in China have been decoupled from the rapid motorization owing to the comprehensive control strategies. China’s increasingly ambitious goals for better air quality are calling for deep emission mitigation, posing a need to develop an up-to-date emission inventory that can reflect the fast-developing policies on vehicle emission control. Herein, large-sample vehicle-emission measurements have been collected to update the vehicle emission inventory. For instance, ambient temperature correction modules were developed to depict the remarkable regional and seasonal emission variations, showing that the monthly emission disparities for total hydrocarbon content (THC) and nitrogen oxide (NOX) in January and July could be up to 1.7 times in northern China. Thus, the emissions ratios of THC and NOX can vary dramatically among various seasons and provinces, which have not been well considered by previous simulations regarding the nonlinear atmospheric chemistry of ozone (O3) and fine particulate matter (PM2.5) formation. The new emission results indicate that vehicular carbon monoxide (CO), THC, and PM2.5 emissions decreased by 69%, 51%, and 61%, respectively, during 2010-2019. However, the controls of NOX and ammonia (NH3) emissions were not as efficient as other pollutants. Under the most likely future scenario (PC [1]), CO, THC, NOX, PM2.5, and NH3 emissions were anticipated to reduce by 35%, 36%, 35%, 45%, and 4%, respectively, from 2019 to 2025. These reductions will be expedited with expected decreases of 56%, 58%, 74%, 53%, and 51% from 2025 to 2035, which are substantially promoted by the massive deployment of new energy vehicles and more stringent emission standards. The updated vehicle emission inventory can serve as an important tool to develop season- and location-specific mitigation strategies of vehicular emission precursors for alleviate haze and O3 problems.
China has made great progress in the electrification of passenger cars, and the sales of battery electric vehicles (BEVs) have exceeded 10%. We applied a life-cycle assessment (LCA) method to estimate the carbon dioxide (CO 2) emissions of the past (2015), present (2020), and future (2030) BEVs, incorporating China's carbon peaking and neutrality policies, which would substantially reduce emissions from the electricity, operation efficiency, metallurgy, and battery manufacturing industries. BEVs can reduce cradle-to-grave (C2G) CO 2 emissions by ∼40% compared with internal combustion engine vehicles (ICEVs) on the national-average level in 2020, far more significant than the benefit in 2015. Improved BEV operating efficiency was the largest factor driving emission reductions from 2015 to 2020. Looking forward to 2030, China's BEVs equipped with nickel-cobalt-manganese (NCM) batteries can achieve a further 43% of CO 2 emissions reductions, among which 51 g km −1 of reduction is from the well-to-wheels (WTW) stage majorly owing to the further cleaner electricity mix, while other vehicle-cycle benefits are mainly from the advancement of battery (12 g km −1) and related metal materials (5 g km −1). We highlight the importance of better material efficiency and synchronized decarbonization through the automotive industrial chain in promoting climate mitigation from transport activities.
The growing urban transport sector presents towns and cities with an escalating challenge in the reduction of their greenhouse gas emissions. Here we assess the effectiveness of several widely considered policy options (electrification, light-weighting, retrofitting, scrapping, regulated manufacturing standards and modal shift) in achieving the transition to sustainable urban mobility in terms of their emissions and energy impact until 2050. Our analysis investigates the severity of actions needed to comply with Paris compliant regional sub-sectoral carbon budgets. We introduce the Urban Transport Policy Model (UTPM) for passenger car fleets and use London as an urban case study to show that current policies are insufficient to meet climate targets. We conclude that, as well as implementation of emission-reducing changes in vehicle design, a rapid and large-scale reduction in car use is necessary to meet stringent carbon budgets and avoid high energy demand. Yet, without increased consensus in sub-national and sectoral carbon budgets, the scale of reduction necessary stays uncertain. Nevertheless, it is certain we need to act urgently and intensively across all policy mechanisms available as well as developing new policy options.
The transportation sector is a crucial source of greenhouse gas emissions, and the degree of its low-carbon transformation is closely related to the achievement of China’s carbon neutrality. Based on high-frequency passenger vehicle sales data and motor vehicle real-time monitoring big data, we developed a low-carbon transition planning model of China road transport (CRT-LCTP) to explore the pathways toward carbon neutrality. The study found that although the number of new energy vehicles (NEVs) increased four times from 2016 to 2019, the average annual growth rate of road traffic emissions was still as high as 20.5%. The current transportation electrification may only reduce 0.6% of the total emissions in this sector, and it could be increased to 1.4% if the electricity completely came from clean energy. Under the enhanced policy scenario, the transport sector could peak its carbon emissions at around of 2030, with the peak level being 1330.98 Mt. Transportation electrification along could not meet the climate targets in 2060, and the continued inertia of fuel vehicles will slow the path of the road transport toward carbon neutrality, which depends on the forced elimination of fuel vehicles and more substantive decarbonization measures.
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.
Shared cars will likely have larger annual vehicle driving distances than individually owned cars. This may accelerate passenger car retirement. Here we develop a semi-empirical lifetime-driving intensity model using statistics on Swedish vehicle retirement. This semi-empirical model is integrated with a carbon footprint model, which considers future decarbonization pathways. In this work, we show that the carbon footprint depends on the cumulative driving distance, which depends on both driving intensity and calendar aging. Higher driving intensities generally result in lower carbon footprints due to increased cumulative driving distance over the vehicle’s lifetime. Shared cars could decrease the carbon footprint by about 41% in 2050, if one shared vehicle replaces ten individually owned vehicles. However, potential empty travel by autonomous shared vehicles—the additional distance traveled to pick up passengers—may cause carbon footprints to increase. Hence, vehicle durability and empty travel should be considered when designing low-carbon car sharing systems.
Countries such as China are facing a bottleneck in their paths to carbon neutrality: abating emissions in heavy industries and heavy-duty transport. There are few in-depth studies of the prospective role for clean hydrogen in these ‘hard-to-abate’ (HTA) sectors. Here we carry out an integrated dynamic least-cost modelling analysis. Results show that, first, clean hydrogen can be both a major energy carrier and feedstock that can significantly reduce carbon emissions of heavy industry. It can also fuel up to 50% of China’s heavy-duty truck and bus fleets by 2060 and significant shares of shipping. Second, a realistic clean hydrogen scenario that reaches 65.7 Mt of production in 2060 could avoid US$1.72 trillion of new investment compared with a no-hydrogen scenario. This study provides evidence of the value of clean hydrogen in HTA sectors for China and countries facing similar challenges in reducing emissions to achieve net-zero goals.
The passenger car sector accounts for nearly half of all transport-related emissions. Rapid decarbonization is therefore important but challenging, particularly in China, where, despite recent emission peak (by 2030) and carbon-neutrality (by 2060) pledges, car ownership and associated emissions are increasing. Successful emissions reduction will require a rapid transition of both technology (e.g., toward electrification) and demand (e.g., driving less). However, how to successfully deploy these twin strategies for optimal outcomes remains unclear. Here, we develop an integrated fleet dynamics model that considers emissions associated with car manufacturing, operation, end-of-life recycling, and energy supply alongside socioeconomic changes. Our analyses reveal that optimal short-term results will be achieved through demand-oriented strategies, which can reduce emissions by 22% and achieve 2030 emissions peak targets. Technology-oriented strategies are more optimal when deployed in the longer term and can result in emission reductions of 91%. A successfully coordinated strategy could reduce China’s passenger cars CO2 emissions to 0.05 Gt by 2050.
China needs to drastically reduce carbon dioxide (CO2) emissions from heavy-duty trucks (HDTs), a key emitter in the growing transport sector, in order to address energy security concerns and meet its climate targets. We address existing research gaps by modeling feasibility, applicability, and energy and emissions impacts of multiple decarbonization strategies at different points in time. China still relies heavily on coal power, so impacts of new HDT technologies depend on the timing of their introduction relative to progress toward non-fossil power. We use a bottom-up model to simulate HDT energy consumption and CO2 emissions through 2050. Results show that beginning to deploy battery electric and fuel-cell HDTs as early as 2020 and 2035, respectively, could achieve significant and the largest CO2 emissions reduction by 2050 with a decarbonized power sector. However, viable near-term strategies—improving efficiency and logistics, switching to liquefied natural gas—could halve HDTs’ current diesel consumption and CO2 emissions by 2050. Our results underscore the need for a mix of near- and long-term policy and technology options to decarbonize China’s HDTs.
Switching to electricity in the ground transport sector is considered a promising way to achieve the energy transition and CO2 emission reductions required to meet China's carbon neutral target by 2060. In this study, a transport energy model containing an elaborate transport demand model and a technology bottom-up model for detailed behavioral and technological representations was developed to investigate how electric vehicles (EVs) will penetrate the markets in the long-term and what impacts on energy consumption and emissions would emerge following EV adoption in China at the provincial level. A set of scenarios was created based on different policy interventions for the promotion of electric mobility. The results showed that subsidies for EV adoption would significantly boost the market share and foster a rapid transition away from fossil fuels, while the business-as-usual scenario would only generate a moderate influence on EV penetration. The regional differences in the emission reduction potential due to EV subsidies across the 31 provinces indicated that policy instruments for EV promotion would have significant positive effects in the developed provinces in both the capital metropolitan area and southeastern China. An economic cost analysis revealed a relatively low economic feasibility in northeastern and northwestern regions where the emission reduction potential is also lower than the national average, implying that the developing provinces in northeastern and northwestern China require greater financial assistance and the establishment of supportive policies for EV promotion.
Climate change mitigation strategies are often technology-oriented, and electric vehicles (EVs) are a good example of something believed to be a silver bullet. Here we show that current US policies are insufficient to remain within a sectoral CO2 emission budget for light-duty vehicles, consistent with preventing more than 2 °C global warming, creating a mitigation gap of up to 19 GtCO2 (28% of the projected 2015–2050 light-duty vehicle fleet emissions). Closing the mitigation gap solely with EVs would require more than 350 million on-road EVs (90% of the fleet), half of national electricity demand and excessive amounts of critical materials to be deployed in 2050. Improving average fuel consumption of conventional vehicles, with stringent standards and weight control, would reduce the requirement for alternative technologies, but is unlikely to fully bridge the mitigation gap. There is therefore a need for a wide range of policies that include measures to reduce vehicle ownership and usage.
Natural gas vehicles (NGVs) have been promoted in China to mitigate air pollution, yet our measurements and analyses show that NGV growth in China may have significant negative impacts on climate change. We conducted real-world vehicle emission measurements in China and found high methane emissions from heavy-duty NGVs (90% higher than current emission limits). These emissions have been ignored in previous emission estimates, leading to biased results. Applying our observations to life-cycle analyses, we found that switching to NGVs from conventional vehicles in China has led to a net increase in greenhouse gas (GHG) emissions since 2000. With scenario analyses, we also show that the next decade will be critical for China to reverse the trend with the upcoming China VI standard for heavy-duty vehicles. Implementing and enforcing the China VI standard is challenging, and the method demonstrated here can provide critical information regarding the fleet-level CH4 emissions from NGVs.
The large (26-fold over the past 25 years) increase in the on-road vehicle fleet in China has raised sustainability concerns regarding air pollution prevention, energy conservation, and climate change mitigation. China has established integrated emission control policies and measures since the 1990s, including implementation of emission standards for new vehicles, inspection and maintenance programs for in-use vehicles, improvement in fuel quality, promotion of sustainable transportation and alternative fuel vehicles, and traffic management programs. As a result, emissions of major air pollutants from on-road vehicles in China have peaked and are now declining despite increasing vehicle population. As perhaps might be expected, progress in addressing vehicle emissions has not always been smooth and challenges such as the lack of low sulfur fuels, frauds over production conformity and in-use inspection tests, and unreliable retrofit programs have been encountered. Considering the high emission density from vehicles in East China enhanced vehicle, fuel and transportation strategies will be required to address vehicle emissions in China.
We project the total vehicle population in China to reach 400 - 500 million by 2030. Serious air pollution problems in many cities of China, in particular high ambient PM2.5 concentration, have led to pressure to accelerate the progress on vehicle emission reduction. A notable example is the draft China 6 emission standard released in May 2016, which contains more stringent emission limits than those in the Euro 6 regulations, and adds a real world emission testing protocol and a 48-h evaporation testing procedure including diurnal and hot soak emissions. A scenario (PC[1]) considered in this study suggests that increasingly stringent standards for vehicle emissions could mitigate total vehicle emissions of HC, CO, NOX and PM2.5 in 2030 by approximately 39%, 57%, 59% and 81%, respectively, compared with 2013 levels. With additional actions to control the future light-duty passenger vehicle population growth and use, and introduce alternative fuels and new energy vehicles, the China total vehicle emissions of HC, CO, NOX and PM2.5 in 2030 could be reduced by approximately 57%, 71%, 67% and 84%, respectively, (the PC[2] scenario) relative to 2013. This paper provides detailed policy roadmaps and technical options related to these future emission reductions for governmental stakeholders.
Reliable national statistics are fundamental for climate change science as well as for global negotiations about future emission targets and the allocation of responsibilities. China, the world’s top CO2 emitter1, 2, has frequently been questioned about its data transparency and accuracy of energy and emission statistics 3, 4, 5, 6, 7. China implemented a top-down statistical system where energy statistics are compiled under the aegis of the National Bureau of Statistics (NBS) at the central government level, which oversees and coordinates the corresponding statistical departments at provincial and county levels8. The NBS publishes annually both national and provincial energy statistics. We compile the CO2 emission inventories for China and its 30 provinces for the period 1997–2010. However, CO2 emissions calculated on the basis of the two publicly available official energy data sets differ by 1.4 gigatonnes for 2010. The figure is equivalent to Japan’s annual CO2 emissions, the world’s fourth largest emitter, with 5% of the global total. Differences in reported coal consumption in coal washing and manufacturing are the main contributors to the discrepancy in official energy statistics. This paper presents an initial step to share and validate data and discuss methodologies in full transparency towards better energy and emission data for China.
Nitrogen oxides (NOx) emissions from heavy-duty diesel vehicles (HDDVs) have adverse effects on human health and the environment. On-board monitoring (OBM), which can continuously collect the vehicle performance and NOx emissions throughout the operation lifespan, is recognized as the core technology for future vehicle in-use compliance, but its large-scale application has not been reported. Here, we utilized OBM data from 22,520 HDDVs in China to evaluate their real-world NOx emissions during hot-running. Our findings showed that China VI HDDVs had 73% NOx emission reduction compared with China V vehicles, but a considerable proportion still faced a significant risk of higher NOx emissions than the corresponding limits. The unsatisfactory efficiency of emission treatment system under disadvantageous driving conditions (e.g., low speed or ambient temperature) resulted in the incompliance of NOx emissions, especially for utility vehicles (sanitation/garbage trucks). Furthermore, the observed inter-trip and seasonal variability of NOx emissions demonstrated the need of long-term continuous monitoring protocol instead of instantaneous evaluation for OBM. With both functions of emission monitoring and malfunction diagnostic, OBM has the potential of accurately verifying the in-use compliance status of large-scale HDDVs and discerning the responsibility of high-emitting activities from the manufacturers, vehicle operators and driving conditions.
A widening gap between official and real-world fuel consumption of passenger cars has been reported worldwide. However, previous policy evaluation has not adequately incorporated real-world performance. To comprehensively evaluate China’s orporate Average Fuel Consumption (CAFC) policy, we update the fuel
consumption gap with millions of consumer-reported records and calculate CAFC and evaluate the national average fuel consumption (NAFC) under four scenarios. The results show that China’s fuel consumption gap has reached 37%. The average CAFC decreases from 6.72 L/100 km in 2016 to 5.91 L/100 km in 2020, far slower than the rated performance. The real-world NAFC non-compliance is disaggregated into on-road discrepancy (2.5 L/100 km), new-energy discounts (0.4 L/100 km), lightweight impacts (0.3 L/100 km), and additional technology improvements (0.8 L/100 km). This study can improve the state-of-the-art understanding of the realworld fuel consumption of passenger cars in China, thus calling for a more real-world-featured regulation system.
China has committed to peaking its CO2 emissions by 2030 in order to achieve its 2060 carbon neutrality target. Heavy-duty trucks (HDTs) are an important area to decarbonize, given the continuously rising greenhouse gas (GHG) emissions in this sector. Various low-carbon options have emerged, yet a comprehensive understanding of the extent to which these options can decarbonize HDT throughout the life cycle remains limited. Here, we adopt a life-cycle analysis to assess and compare the GHG mitigation potential ofhighly efficient diesel engines, battery-electrics, and hydrogen fuel cells for China’s class-8 HDTs in 2030. Results show that all three options could enable >38% life-cycle GHG reductions. The battery-electric option, however, requires well-established fast-charging infrastructures to maintain the freight-carrying capacity that will otherwise be compromised by larger batteries. Hydrogen fuel cells can attain 80% reduction when paired with low-carbon hydrogen. Hybrid strategies, including improving engine efficiency, decarbonizing power grids, optimizing freight logistics, and incentivizing behavioral changes, are necessary for the efficient and effective HDT decarbonization that is key to China achieving carbon neutrality by 2060.
China’s road transport sector plays an important role in meeting carbon early peaking and carbon neutrality goals. This study examines how the sector might be decarbonized by modelling five scenarios using the LEAP model. This study aims to inform China road transport sector’s emission reduction target, identification of cost-effective measures that deliver on the sectoral emission reduction targets, facilitate low-carbon investments, and identification of decarbonization measures with air pollution reduction co-benefits.
Electric vehicles (EVs) are a promising pathway to providing cleaner personal mobility. China provides substantial supports to increase EV market share. This study provides an extensive analysis of the currently unclear environmental and health benefits of these incentives at the provincial level. EVs in China have modest cradle-to-gate CO2 benefits (on average 29%) compared to conventional internal combustion engine vehicles (ICEVs), but have similar carbon emissions relative to hybrid electric vehicles. Well-to-wheel air pollutant emissions assessment shows that emissions associated with ICEVs are mainly from gasoline production, not the tailpipe, suggesting tighter emissions controls on refineries are needed to combat air pollution problems effectively. By integrating a vehicle fleet model into policy scenario analysis, we quantify the policy impacts associated with the passenger vehicles in the major Chinese provinces: broader EV penetration, especially combined with cleaner power generation, could deliver greater air quality and health benefits, but not necessarily significant climate change mitigation. The total value to society of the climate and mortality benefits in 2030 is found to be comparable to a prior estimate of the EV policy's economic costs.
As the country with the largest anthropogenic CO 2 emission, China is greatly influential on fighting with climate change. However, CO 2 emitted from on-road vehicles in China is a barrier to its carbon neutral due to the inevitable increase trend of vehicle quantity. Thus, to meet the requirement of refined policy-making for vehicular CO 2 abatement, we calculated the CO 2 emissions from 37 vehicular types and 3 fuel categories across 339 cities in China through the bottom-up method, and developed a national vehicular CO 2 emission inventory in a high spatial resolution (1 km × 1 km). Additionally, machine learnings were conducted to the inventory for the emission pattern identification. It was found that the total vehicular CO 2 emission in 2019 was 1090 million tons, and 77.1% of CO 2 was emitted by vehicles of light-duty gasoline vehicle (LDGV) and heavy-duty diesel truck (HDDT). In addition, for the grids accompanying CO 2 emissions, 75% of vehicular CO 2 emissions were contributed by 15% of grids (hot grids). Furthermore, results of machine learning showed that LDGVs mainly distributed in economically advanced regions of which vehicular structures were relatively simple, while HDDTs were widely applied on the national scale. Based on the results above, two measures were proposed: (1) Electric cars have to be strongly promoted in hot grids for the LDGV replacement. (2) Long-distance freight tool replacements are urgently required in the national wide. Our study provided a studying base for further investigations on decarbonization and a new insight of China's vehicular CO 2 emission controls.
China is the world's largest carbon emitter and suffers from severe air pollution, which results in approximately one million premature deaths/year. Alternative energy vehicles (AEVs) (electric, hydrogen fuel cell, and natural gas vehicles) can reduce carbon emissions and improve air quality. However, climate, air quality, and health benefits of AEVs powered with deeply decarbonized power generation are poorly quantified. Here, we quantitatively estimate the air quality, health, carbon emission, and economic benefits of replacing internal combustion engine vehicles with various AEVs. We find co-benefits increase dramatically as the electricity grid decarbonizes and hydrogen is produced from non-fossil fuels. Relative to 2015, a conversion to AEVs using largely non-fossil power can reduce air pollution and associated premature mortalities and years of life lost by ∼329,000 persons/year and ∼1,611,000 life years/year. Thus, maximizing climate, air quality, and health benefits of AEV deployment in China requires rapid decarbonization of the power system.
Research on the decarbonization of transport often concludes that heavy battery electric trucks are infeasible due to the incompatibility of long driving distance with high energy use and low specific energy and high costs of batteries. However, emphasis is often placed on battery electric range matching that of diesel trucks, instead of overall competitiveness. We model battery electric trucks that use high-power fast charging, enabling smaller batteries and showing that the economics of battery electric trucks per ton-kilometer improves with greater weight, driven by increasing load capacity as well as increased energy savings as a function of weight. Furthermore, we show that previous findings that the competitiveness per kilometer is worse for heavy trucks than for lighter trucks are very sensitive to assumptions about the battery cost per kWh and lifetime of the battery pack. Given the rapid development of batteries, we conclude that the economic feasibility of heavy battery electric trucks might have been generally underestimated.
The recent release of hydrogen economy roadmaps for several major countries emphasizes the need for accelerated worldwide investment in research and development activities for hydrogen production, storage, infrastructure and utilization in transportation, industry and the electrical grid. Due to the high gravimetric energy density of hydrogen, the focus of technologies that utilize this fuel has recently shifted from light-duty automotive to heavy-duty vehicle applications. Decades of development of cost-effective and durable polymer electrolyte membrane fuel cells must now be leveraged to meet the increased efficiency and durability requirements of the heavy-duty vehicle market. This Review summarizes the latest market outlooks and targets for truck, bus, locomotive and marine applications. Required changes to the fuel-cell system and operating conditions for meeting Class 8 long-haul truck targets are presented. The necessary improvements in fuel-cell materials and integration are also discussed against the benchmark of current passenger fuel-cell electric vehicles. Fuel cells are increasingly being considered for powertrains of heavy-duty transportation. Cullen et al. survey the technical challenges of fuel cells at both the system and materials level for transportation application and outline the roadmap for future development.
Lithium-ion batteries are currently the most advanced electrochemical energy storage technology due to a favourable balance of performance and cost properties. Driven by forecasted growth of the electric vehicles market, the cell production capacity for this technology is continuously being scaled up. However, the demand for better performance, particularly higher energy densities and/or lower costs, has triggered research into post-lithium-ion technologies such as solid-state lithium metal, lithium–sulfur and lithium–air batteries as well as post-lithium technologies such as sodium-ion batteries. Currently, these technologies are being intensively studied with regard to material chemistry and cell design. In this Review, we expand on the current knowledge in this field. Starting with a market outlook and an analysis of technological differences, we discuss the manufacturing processes of these technologies. For each technology, we describe anode production, cathode production, cell assembly and conditioning. We then evaluate the manufacturing compatibility of each technology with the lithium-ion production infrastructure and discuss the implications for processing costs.
Enhancing automobile fuel efficiency is crucial to decarbonizing the transport sector. Recent studies have revealed a gap between real-world fuel efficiency and results from laboratory tests, where “off-cycle” auxiliary devices, like air conditioning (AC) systems, are not turned on. AC consumes the most energy among all off-cycle devices; however, the exact contribution of AC to fuel consumption remains unclear. Here, by analyzing 1 million trip-level fuel efficiency records from China, we show that AC use when the temperature exceeds 25°C increases gasoline consumption annually by 1.3%. The amount differs across car models, with those produced by Chinese manufacturers showing relatively lower AC efficiency. Improving AC efficiency could cost-effectively reduce CO2 emissions by 1.6–2.4 million tons in China every year. Therefore, we suggest integrating off-cycle devices into future fuel efficiency regulations, which will reveal the fuel efficiency gap, incentivize car manufacturers to develop high-efficiency devices, and further tap this emissions reduction potential.
Significance
On-road vehicles have become a significant source of air pollution in Chinese cities. Air pollution in China has substantial impacts on public health and is thought to be responsible for millions of deaths each year. The government has implemented comprehensive control measures to mitigate vehicle emissions since the late 1990s. In this paper, we analyze how the historical control actions during 1998–2015 affected air quality and public health. We constructed an integrated framework combining emission scenarios, air quality modeling, and population health risk assessment. Our results demonstrate that the control measures have led to substantial improvements in public health and provide insight into strategies for further mitigation of negative effects from China’s future motorization on air quality and public health.
The pandemic of coronavirus disease 2019 (COVID-19) resulted in a stringent lockdown in China to reduce the infection rate. We adopted a machine learning technique to analyze the air quality impacts of the COVID-19 lockdown from January to April 2020 for six megacities with different lockdown durations. Compared with the scenario without a lockdown, we estimated that the lockdown reduced ambient NO2 concentrations by 36-53% during the most restrictive periods, which involved Level-1 public health emergency response control actions. Several cities lifted the Level-1 control actions during February and March, and the avoided NO2 concentrations subsequently dropped below 10% in late April. Traffic analysis during the same periods in Beijing and Chengdu confirmed that traffic emission changes were a major factor in the substantial NO2 reduction, but they were also associated with an increased O3 concentration. The lockdown also reduced PM2.5 concentrations, although heavy pollution episodes occurred on certain days due to the enhanced formation of secondary aerosols in association with the increased atmospheric oxidizing capacity. We also observed that the changes in air pollution levels decreased as the lockdown was gradually eased in various cities.
Transport CO2 emissions continue to grow globally despite advances in low-carbon technology and goal setting by numerous governments. In this Perspective, we summarize available evidence for the effectiveness of climate policies and policy mixes for road transport relative to 2030 and 2050 mitigation goals implied by the Paris Agreement. Current policy mixes in most countries are not nearly stringent enough. We argue that most regions need a stronger, more integrated policy mix led by stringent regulations and complemented by pricing mechanisms as well as other efforts to reduce vehicle travel. As road transport emissions are set to grow, stronger policy mixes are needed to reach mitigation goals. This Perspective considers the evidence for several policy types—strong regulation, pricing and reduced travel—and the best combination to reduce emissions for passenger and freight vehicles.
We develop a framework for comparing carbon-neutral synthetic fuels (CNSFs) with battery electric vehicles (BEVs) as alternatives to reducing CO2 emissions from light-duty vehicles. CNSFs can be divided into fuels produced from biomass via gasification and electrofuels produced from CO2 and water using electricity. We develop CNSF cost estimates for first-of-a-kind plants operating at commercial scale. Although already competitive over short distances, we find that longer-range BEVs are likely to remain more expensive than CNSFs even if low (∼130/tCO2 or oil prices in excess of $100/bbl to become commercially viable relative to petroleum. The viability of electrofuels ultimately depends on access to low-cost, ultra-low-carbon power systems or sources of zero-carbon electricity with high annual availability. Priorities should include deploying a portfolio of CNSF technologies to help appraise decarbonization pathways, economies of scale, and learning by doing.
Energy security and environmental issues have drawn great attentions to the energy consumption and greenhouse gas (GHG) emissions in the road transport sector. With economic development, travel demands and logistics demands will continue to rise in China. To solve the associated problems, policies related to electric vehicle (EV) promotion and fuel economy regulations are being adopted by the state government. Six scenarios, based on different policies, are analyzed to calculate vehicle fleet GHG emissions in this research by developing a bottom-up modeling framework from a life-cycle perspective. When only fuel economy regulations are considered, GHG emissions from the road transport sector will reach their peak in 2047. However, combined with EV deployment, the peak will arrive earlier, in 2026. In the short term, more stringent fuel economy regulations exhibit better results. Without EVs, fuel economy regulations will be tougher for corporations to meet than with the introduction of EVs. However, in the long term, with a higher proportion of EVs, GHG emissions will further decrease. In addition, the introduction of EVs will weaken the effects of fuel economy regulations, especially for passenger vehicles, due to credit policies. The lack of EVs in the commercial vehicle fleet will impart more significance to the fuel economy regulations. Commercial vehicles, particularly trucks, will account for the majority of GHG emissions by the whole vehicle fleet. In brief, the government should persistently focus on the fuel economy regulations to achieve an early and relatively low-level peak in vehicle fleet GHG emissions. Meanwhile, the promotion of EVs will have the long-term effect of de-carbonization. In addition, more effective measures should be taken to reduce the truck GHG emissions.
It is widely accepted that for electric vehicles to be accepted by consumers and to achieve wide market penetration, ranges of at least 500 km at an affordable cost are required. Therefore, significant improvements to lithium-ion batteries (LIBs) in terms of energy density and cost along the battery value chain are required, while other key performance indicators, such as lifetime, safety, fast-charging ability and low-temperature performance, need to be enhanced or at least sustained. Here, we review advances and challenges in LIB materials for automotive applications, in particular with respect to cost and performance parameters. The production processes of anode and cathode materials are discussed, focusing on material abundance and cost. Advantages and challenges of different types of electrolyte for automotive batteries are examined. Finally, energy densities and costs of promising battery chemistries are critically evaluated along with an assessment of the potential to fulfil the ambitious target.
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Energy consumption and greenhouse gas (GHG) emissions of China’s road transport sector have been increasing rapidly in recent years. Previous studies on the future trends trend to focus on the national picture and cannot offer regional insights. We build a novel bottom-up model to estimate the future energy demand and GHG emissions of China’s road transport at a provincial level, considering local economic development, population and policies. Detailed technical characteristics of the future vehicle fleets are analyzed in several up-to date scenarios. The results indicate that China’s vehicle stock will keep increasing to 543 million by 2050. The total direct petroleum demand and associated GHG emissions will peak at 508 million tonnes of oil equivalent (Mtoe) and 1500 million tonnes CO2 equivalent (Mt CO2,e) around 2030 in the Reference scenario. Natural gas vehicle diffusion has a large impact on petroleum demand reduction in the short term, with decreases of 41–46 Mtoe in 2050. Compared to the Reference case, battery electric and fuel cell vehicles will reduce petroleum demand by 94–157 and 28–54 Mtoe in 2050, respectively. When combined with decarbonization of future power supply, battery electric vehicles can play a significant role in reducing Well-to-Wheels GHG emissions in 2050 with 295–449 Mt CO2,e more reductions. The spatial distributions of future vehicle stock, energy demand and GHG emissions vary among provinces and show a generally downward trend from east to west. Policy recommendations are made in terms of the development of alternative fuels and vehicle technologies considering provincial differences, expansion of natural gas vehicle market and acceleration of electric vehicle market penetration.
Using the Transportation Mode-Technology-Energy-CO2 (TMOTEC) model which is based on discrete choice mothed and general transport cost simulation, this study made a scenario analysis of energy consumption and reductions in CO2 emissions in China’s transport sector. We used scenarios to investigate the relative influences of improving vehicle energy efficiency, promoting EV use, and increasing taxes for fossil fuels and CO2. We found that in the reference scenario, total transport energy consumption would increase to 636 million tons of oil equivalent (Mtoe) in 2050; that would result in 1602 million tons of CO2 emissions. In the comprehensive development scenario, transport energy consumption would peak at 497 Mtoe around 2045; the resulting CO2 emissions peak would be 1129 million tons of CO2 between 2040 and 2045. Both energy consumption and CO2 emissions in the transport sector would decline steadily after reaching their peak. We believe that the Chinese government should make greater efforts with vehicle fuel economy standards, in improving technological progress and market expansion of EVs, and in increasing taxes on traditional transport energy and CO2. This would contribute to reducing energy consumption and achieving a CO2 emissions peak in China’s transport sector as soon as possible.
The California Air Resources Board (ARB) and the City of Sacramento undertook this study to characterize the in-use emissions from model year (MY) 2010 or newer diesel, liquefied natural gas (LNG) and hydraulic hybrid diesel engines during real-world refuse truck operation. Emissions from five trucks: two diesels equipped with selective catalytic reduction (SCR), two LNG’s equipped with three-way catalyst (TWC) and one hydraulic hybrid diesel equipped with SCR were measured using a portable emissions measurement system (PEMS) in the Sacramento area. Results showed that the brake-specific NOx emissions for the LNG trucks equipped with the TWC catalyst were lowest of all the technologies tested. Results also showed that the brake specific NOx emissions from the conventional diesel engines were significantly higher despite the exhaust temperature being high enough for proper SCR function. Like diesel engines, the brake specific NOx emissions from the hydraulic hybrid diesel also exceeded certification although this can be explained on the basis of the temperature profile. Future studies are warranted to establish whether the below average SCR performance observed in this study is a systemic issue or is it a problem specifically observed during this work.
This paper presents the overview of the Shared Socioeconomic Pathways (SSPs) and their energy, land
use, and emissions implications. The SSPs are part of a new scenario framework, established by the
climate change research community in order to facilitate the integrated analysis of future climate
impacts, vulnerabilities, adaptation, and mitigation. The pathways were developed over the last years as a
joint community effort and describe plausible major global developments that together would lead in the
future to different challenges for mitigation and adaptation to climate change. The SSPs are based on
five
narratives describing alternative socio-economic developments, including sustainable development,
regional rivalry, inequality, fossil-fueled development, and middle-of-the-road development. The longterm
demographic and economic projections of the SSPs depict a wide uncertainty range consistent with
the scenario literature. A multi-model approach was used for the elaboration of the energy, land-use and
the emissions trajectories of SSP-based scenarios. The baseline scenarios lead to global energy
consumption of 400–1200 EJ in 2100, and feature vastly different land-use dynamics, ranging from a
possible reduction in cropland area up to a massive expansion by more than 700 million hectares by 2100. The associated annual CO2 emissions of the baseline scenarios range from about 25 GtCO2 to more than
120 GtCO2 per year by 2100. With respect to mitigation, we
find that associated costs strongly depend on
three factors: (1) the policy assumptions, (2) the socio-economic narrative, and (3) the stringency of the
target. The carbon price for reaching the target of 2.6 W/m2 that is consistent with a temperature change
limit of 2 �C, differs in our analysis thus by about a factor of three across the SSP marker scenarios.
Moreover, many models could not reach this target from the SSPs with high mitigation challenges. While
the SSPs were designed to represent different mitigation and adaptation challenges, the resulting
narratives and quantifications span a wide range of different futures broadly representative of the current
literature. This allows their subsequent use and development in new assessments and research projects.
Critical next steps for the community scenario process will, among others, involve regional and sectoral
extensions, further elaboration of the adaptation and impacts dimension, as well as employing the SSP
scenarios with the new generation of earth system models as part of the 6th climate model
intercomparison project (CMIP6).
The rapid growth of vehicles has resulted in continuing growth in China’s oil demand. This paper analyzes future trends of both direct and life cycle energy demand (ED) and greenhouse gas (GHG) emissions in China’s road transport sector, and assesses the effectiveness of possible reduction measures by using alternative vehicles/fuels. A model is developed to derive a historical trend and to project future trends. The government is assumed to do nothing additional in the future to influence the long-term trends in the business as usual (BAU) scenario. Four specific scenarios are used to describe the future cases where different alternative fuel/vehicles are applied. The best case scenario is set to represent the most optimized case. Direct ED and GHG emissions would reach 734 million tonnes of oil equivalent and 2384 million tonnes carbon dioxide equivalent by 2050 in the BAU case, respectively, more than 5.6 times of 2007 levels. Compared with the BAU case, the relative reductions achieved in the best case would be 15.8% and 27.6% for life cycle ED and GHG emissions, respectively. It is suggested for future policy implementation to support sustainable biofuel and high efficient electric-vehicles, and the deployment of coal-based fuels accompanied with low-carbon technology.