• Energy Research

With China’s rapid economic development, its transport sector has experienced a dramatic growth, leading to a large amount of related CO2 emission. This paper aims to uncover China’s transport CO2 emission patterns at the regional and provincial level. We first present the CO2 emission features from transport sector in 30 Chinese provinces, including per capita emissions, emission intensities, and historical evolution of annual CO2 emission. We then quantify the related driving forces by adopting both period-wise and time-series LMDI analysis. Results indicate that significant regional CO2 emission disparities exist in China’s transport sector. The eastern region had higher total CO2 emissions and per capita CO2 emissions, but lower CO2 emission intensities in its transport sector. The western region had higher CO2 emission intensities and experienced a rapid CO2 emission increase. The CO2 emission increments in the eastern provinces were mainly contributed by both economic activity effect and population effect, while energy intensity partially offset the emission growth and energy structure had a marginal effect. However, in the central and western provinces, both economic activity effect and energy intensity effect induced the CO2 emission increases, while the effects from population and energy structure change were limited.

Abstract Biofuel is considered to be a promising solution to the energy and environmental challenges in the transport sector. However, there are few studies focusing on the current status, future potential, policy framework, barriers and opportunities of biofuel development in China, these are analyzed in this study. This study finds that China has been promoting biofuel commercialization with multiple measures, including framing national strategy, initiating demonstration programs, providing financial incentives, and establishing national standards. However, due to technology and market barriers, the actual commercialization scale is far lower than previously projected. Accordingly, it is recommended that the development of non-plantation resource-based biofuel should be given high priority, while plantation resource-based biofuel should be developed with caution. Meanwhile, technology innovation for increasing production efficiency and reduce cost is essential for strengthening biofuel market competitiveness. Subsequently, mandatory legal and policy system for regulating the biofuel industry in China should be established, which can effectively engage different stakeholders in promoting biofuel development. Regarding fuel ethanol, the trade price between the fuel ethanol producers and the oil companies should be further adjusted. As for biodiesel, the illegal utilization of waste oil should be strictly prohibited, which can help to increase the feedstock supply, as well as bring down the price. Last but not the least, the financial incentives for biofuel production should also be optimized.

The newly launched new energy vehicle credit regulation scheme is expected to have a dramatic impact on the development of the Chinese and global new energy vehicle markets. This paper establishes a bottom-up framework to estimate the impacts of regulation on the technological trends of battery electric vehicles based on the most up-to-date data from the market in China. The results suggest that mini-electric cars will always be the most credit cost-effective. Moreover, 350 km will be the optimal driving range under the credit regulation. With the development of energy-saving technologies, midsize electric vehicles will increase in popularity before 2020 and be the first to receive the highest credit of 6. Additionally, promoted by the regulation, the investment in energy-saving technologies will reduce the cost of batteries and lead to higher credits, especially for large-class and high electric range vehicles. However, the regulation likely faces the risk of losing this positive effect in 2025 or even earlier. To avoid such a circumstance, the relevant policies should be modified before such a scenario occurs.

Abstract 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.

The switching from new European driving cycle (NEDC) to worldwide harmonized light vehicles test procedure (WLTP) will affect the energy consumption of plug-in hybrid electric vehicle (PHEV), and then affect the new energy vehicle (NEV) credit regulation and subsidy policy for PHEVs. This paper reveals the impact on energy consumption, NEV credit regulation, and subsidy policy for PHEV in the Chinese market of the switching from NEDC to WLTP based on qualitative analysis and quantitative calculation. The results show that the WLTP procedure is stricter than NEDC in the determination of road load, test mass, driving resistance forces, and tire selection. Firstly, the electricity consumption (EC) of PHEV in charge-depleting mode (CD) under the WLTP procedure is 26% higher than NEDC on average, which makes the all-electric range (AER) significantly lower under WLTP. The weight EC tested in the WLTP procedure is higher than NEDC. Secondly, the fuel consumption (FC) of PHEV in CD mode is related to the adjustment of the engine management system (EMS) and the size of battery energy under the WLTP procedure. For the FC in the charge-sustaining (CS) mode of PHEV under the WLTP procedure is 20% higher than NEDC on average. However, the weight fuel consumption of PHEVs under WLTP with a long AER may be lower than that of NEDC due to the characteristics of utility factor in the WLTP procedure. Thirdly, most PHEVs fail to meet the requirements of 50 km AER due to the switching of the test procedures. However, the Chinese government reduced the technical specification of PHEV’s AER under the WLTP procedure to 43 km to support the development of PHEV technology. It ensures that the switching of test procedures does not change the treatment that they could obtain, the NEV credits, and subsidy as a NEV in China. However, the increasing of the EC in CD mode and the FC in CS mode under the WLTP procedure makes the PHEV obtain lower credit and subsidy multiple compared with NEDC procedure.

Lithium-ion battery (LIB) is the key technology for climate change mitigation. The sustainability of LIB supply chain has caused widespread concern since the material utilization efficiency of LIB supply chain has not been well investigated. This study aims to fill this research gap by conducting a dynamic material flow analysis of lithium in China from 2015 to 2021. Results indicate that within the temporal boundary, lithium flow and in-use stock grew significantly in China due to the rapid development of the EV market, with lithium flow in domestic production of basic chemicals increasing by 614% to 100 kt, end-use consumption increasing by 160% to 35 kt, and in-use stock increasing by 62% to 195 kt. China has been a net importer of lithium, of which cumulative imports and exports were 343 kt and 169 kt, respectively. In addition, 103 kt of lithium was converted to inventories or was lost during the processing from 2015 to 2021. By optimizing inventory and processing, developing substitutes for lithium for non-battery applications, and improving lithium recycling, China's net import dependency of lithium could be reduced from 27%-86% to 0%-16%. Our study demonstrates that it is urgent to improve material utilization efficiency so that the lithium resource supply can be secured.

Abstract A super credit policy provides favorable accounting rules for extremely low emission vehicles under several passenger vehicle fuel economy regulations. This policy was initially designed to promote promising advanced technologies complying with fleet-wide fuel economy regulations so that these technologies could achieve cost-effective breakeven points. The favorable multipliers offered range from 3.5 to 1.33 in the various fuel economy regulations by the year 2021. Under China's Corporate Average Fuel Consumption regulation, two types of super credit schemes are designed in the Phase IV Corporate Average Fuel Consumption regulation through 2020. One is the fuel-efficient vehicle super credit for vehicles with fuel consumption rates below the threshold of 2.8 L/100 km. Another is the new energy vehicle super credit for battery electric vehicles and plug-in hybrid electric vehicles. However, the effectiveness of this incentive in promoting electric vehicles and the optimal size of the multiplier are not well understood. This paper analyzes the impacts of the super credit policy from the perspective of automakers. A mathematical model based on combinational optimization is established to describe an automaker's decision-making process, and a genetic algorithm is employed to solve this problem. The conventional and plug-in hybrid electric vehicles cost-effectiveness frontier curves are fitted to illustrate the principle of new energy vehicle and fuel-efficient vehicle super credit schemes. Various multipliers of new energy vehicle and fuel-efficient vehicle super credit policy scenarios are simulated under the 2020 and 2025 Corporate Average Fuel Consumption targets. By analyzing the impact of the policy on the reduction of compliance costs, the super credit multiplier, the cost and the fuel consumption rates reduction effect are found to be the determining factors. The results confirm that the multiplier and China's super credit policy scheme will be effective by 2020, under which plug-in hybrid electric vehicles would account for 7.8% of the fleet at a cost of 6.6% Corporate Average Fuel Consumption target impairment. Under the assumed next phase of regulation by the year 2025, the optimal multipliers for the new energy vehicle and fuel-efficient vehicle super credit will be 1.5 and 1, respectively. It is noteworthy that the super credit policy may impair the energy saving target of Corporate Average Fuel Consumption regulations while promoting the market penetration of the targeted technologies. Despite other policies that benefit battery electric vehicles over plug-in hybrid electric vehicles, battery electric vehicles are not competitive with plug-in hybrid electric vehicles under either the 2020 or 2025 Corporate Average Fuel Consumption regulations. The fuel-efficient vehicle super credit policy will not promote the targeted advanced technologies under the next phase of regulation unless the 2.8 L/100 km fuel-efficient vehicle definition threshold can be adjusted along with the strengthened 2025 Corporate Average Fuel Consumption target.

Energy conservation and emissions reduction have become increasingly significant for automobiles due to the severity of the current energy situation. Hybrid electric vehicle (HEV) technology is one of the most promising solutions. This study investigated the total efficiency of a HEV powertrain. To improve the total efficiency, the engine should be regulated to work at its highest efficiency and drive the wheels directly as much as possible. To accomplish this, we developed an energy management strategy based on the direct drive area (DDA) of the engine’s efficiency map. Several typical HEV models were built to compare the fuel consumption using DDA and rule-based strategies. Furthermore, the function of the HEV transmission system with DDA was considered. The transmission in a HEV should regulate the engine to work at its highest efficiency as much as possible, which is rather different than the regulation in an internal combustion engine vehicle. The functional change may lead to transmission systems with fewer gears but optimal gear ratios. If this trend is realized, the manufacturing cost of HEVs could be largely reduced.