Xuepeng Qian

To identify the emission reduction potential and policy synergies of Tokyo’s road passenger and urban road freight transport under the “carbon neutrality target,” this paper constructs an assessment framework for megacities. First, based on macroeconomic socioeconomic variables (population, GDP, road length, and employment), regression equations are used to predict traffic turnover for different modes of transport from 2021 to 2050. Then, the prediction results are imported into the LEAP (Long-range Energy Alternatives Planning) model. By adjusting three policy levers—vehicle technology substitution (ZEV: EV/FCEV), energy intensity improvement, and upstream electricity and hydrogen supply decarbonization—a “single-factor vs. multi-factor (policy synergy)” scenario matrix is designed for comparison. The results show that the emission reduction potential of a single measure is limited; upstream decarbonization yields the greatest independent emission reduction effect, while the emission reduction effect of deploying zero-emission vehicles and improving energy efficiency alone is small. In the most ambitious composite scenario, emissions will decrease by approximately 83% by 2050 compared to the baseline scenario, with cumulative emissions decreasing by over 35%. Emissions from rail and taxis will approach zero, while buses and freight will remain the primary residual sources. This indicates that achieving net zero emissions in the transportation sector requires not only accelerated ZEV penetration but also the simultaneous decarbonization of electricity and hydrogen, as well as policy timing design oriented towards fleet replacement cycles. The integrated modeling and scenario analysis presented in this paper provide quantifiable evidence for the formulation of a medium- to long-term emissions reduction roadmap and the optimization of policy mix in Tokyo’s transportation sector.

As the urgency of addressing climate change grows, strategies such as developing zero-emission campuses to achieve carbon neutrality are becoming increasingly crucial. Yet, research in this field remains somewhat underdeveloped and fragmented. This study aims to bridge this gap, providing a scientometric analysis of the research conducted on zero-emission campuses from 1997 to 2023, using data from the Web of Science Core Collection. The study analyzed 1009 bibliographic records with the aid of CiteSpace software, focusing on identifying key co-authors, co-words, co-citations, and clusters. The findings indicate a rapid increase in research in the field of zero-emission campuses, with a significant surge in the number of publications in recent years, culminating in 174 in 2021 alone. The leading universities in terms of publication count were the University of California System, Egyptian Knowledge Bank, and the Chinese Academy of Sciences. Furthermore, the United States, China, and the United Kingdom were identified as the main contributing countries/regions to publishing in this field, indicating a broad, global collaboration. The scope of research has broadened from technical elements, such as energy, to encompass social factors that influence sustainability. Emerging research areas were identified, including education and sustainability, renewable energy and energy efficiency, campus planning and design, waste management and recycling, policy support, and pro-environmental behavior. This study provides a structured overview of the research landscape in the field of zero-emission campuses, offering valuable guidance for academics and encouraging further collaboration. The identified research clusters, notable authors, and influential institutions hold significant implications for policy decisions, industry practices, and the implementation of zero-emission strategies on campuses, aiding in the broader pursuit of sustainability.

Breaking the highly oil-dependent energy use structure in the transportation sector will be crucial for China to reduce its dependence on crude oil imports and ensure its energy security, and the development of new energy vehicles is helping to break this dilemma. A time series analysis summarizes the possible relationships between new energy vehicles and crude oil imports, i.e., new energy vehicles, as alternatives to fuel vehicles, will reduce the demand for oil in the transportation sector, which will in turn reduce crude oil imports, and crude oil prices and crude oil production will inhibit crude oil imports. In this empirical study, monthly data from 2015 to 2021 on crude oil imports, the market share of new energy vehicles, crude oil prices, and crude oil production are selected, time-series multiple regression modelling is adopted, and endogeneity is treated using a generalized method of moments (GMM). The regression results show that crude oil imports decrease by one unit for every 16.32% increase in crude oil prices, indicating that price factor is the most influential factor in China’s crude oil imports, while crude oil imports decrease by one unit for every 133.99% increase in crude oil production, indicating that an increase in crude oil production contributes less to the reduction of crude oil imports. One unit of crude oil imports is added for every 15.53% increase in the share of new energy vehicles, indicating that the effect of new energy vehicles on limiting crude oil imports has not yet emerged. Probably due to the fact that new energy vehicles have not yet had a significant impact on fuel vehicles, oil consumption will continue to increase in the short and medium term, with oil for the petrochemical industry becoming the primary driver of this increase. Finally, policy implications are provided from the perspective of crude oil demand, supply, and China’s oil price mechanism.

Lin, X., Zhou, W., Qian, X., Nakagami, K.