Pathways to deep decarbonization of the passenger transport sector in Japan
Two Deep Decarbonization Pathways Project (DDPP) scenarios are structured to investigate the way in which different technical and social transformations can reduce the transport-related energy use and GHG emissions. An advanced technological (AdvancedTech) scenario focuses mainly on the technological innovations and transformations in the transport and energy sector, but does not give consideration to social and behavioural factors. The GHG emission reduction target under continued economic growth is achieved by large-scale energy demand reduction by end users and decarbonization of power generation. On the other hand, the balanced scenario is structured with the objective of developing a long-term strategy to achieve a drastic GHG emission reduction in transport sector by means of a balanced behavioural and technological changes. Compared with the focus of technological development in the AdvancedTech scenario, the balanced scenario is aimed to explore the maximum reduction potential of GHG emissions from an integrated and combined perspective of both technological innovation and social transformations.
In the AdvancedTech scenario, although the average annual distance travelled per capita increases during 2010 to 2050, the average individual emissions from passenger transport decrease over this period, thanks to the improvement of energy efficiency and emissions intensity. The large electrification in transport sector is the main contributor of emission reduction, followed by the strong decarbonization in the power generation sector through a massive deployment of CCS and renewable energies. The share of renewable energies and CCS-equipped plants reaches high proportions of total electricity generation, thus the GHG emissions in transport sector can be largely reduced by the shift to low-carbon electricity. In the balanced scenario, the emission trajectory shows much lower values than those of the AdvancedTech scenario, thanks to the decreasing individual mobility and modal shift from carbon-intensive modes towards low-carbon modes of transport. Social and behavioural changes in demography, urban structures, land use, lifestyle, infrastructure can effectively contribute to further reduce the GHG emissions above the technological transformations.
A roadmap for moving to a deep decarbonized transport sector is presented by combining low-carbon policy initiatives and measures in consideration of both technological and social transformations such as environmentally-friendly vehicle technologies, CCS-equipped power plants, compact city, mixed and intensified land use, transit-oriented development, pedestrian-friendly street design, lifestyle change, and so forth. In order to alleviate the risks that the deep decarbonization pathway fails and the targets are not achieved as planned, it is necessary to consider which policies are the first priorities for the near future. Since the deep electrification and CCS deployment cannot be achieved in the short-term, the efficiency improvements in conventional internal combustion engine-driven vehicles and aircraft deserve more attentions in the near-term. Social transformations such as low-carbon urban reorganization, teleworking, online shopping also can be effective within a short period.