In the first year, initial analysis was conducted throughout the project, as well as the development of a collaborative structure for the research team. The Integrated Scenario Building Group conducted a literature review on transition acceleration and scenarios for decarbonization. It was found that while there are diverse findings on the acceleration of individual innovations based on various methods, there are limited findings on the acceleration of transitions in socio-technical systems as a whole. The Technology Scenario Assessment Group analyzed the differences between the energy system simulations in the integrated assessment and the simulations on technology design and operation used in the techno-economic analysis and life cycle assessment, and identified intermediate parameters that are responsible for the differences, including the capacity factor. In addition, energy-related technologies currently under consideration were extracted from domestic and overseas projects, and parameter analysis was conducted. Furthermore, social life cycle assessment was conducted as a specific evaluation. The Quantitative Scenario Analysis Group modeled hydrogen and synthetic fuel production and consumption technologies in an integrated assessment model, and in the estimation of the 2050 decarbonization scenario, the amount of hydrogen-related technologies introduced, in particular, varied greatly depending on assumptions. In addition to a close examination of stand-alone technology data, it was suggested that a comprehensive analysis that considers a variety of abatement options is needed. The Social Scenario Dialogue Group conducted a literature review, studied the axes of scenarios, and conducted an expert workshop (WS). The literature review shared the taxonomy of scenarios and other information. Internal pressure (domestic innovation) and external pressure (influence of social, technological, and other factors) were identified as candidate axes. The expert WS confirmed the importance of providing user-specific information, among other issues. The Overall Management Group held various meetings and promoted research. A science and technology dialogue symposium was held in a hybrid format on December 4, 2023 to publicize the results, and the initial version of the project website was also published.

For quantitative scenario analysis focusing on regional characteristics, we developed an energy system model and an input-output model and in addition conducted a basic study on the concept of future social visions at the regional level. First, for the energy system model, we developed an energy system model “NE_Japan-Region” with enhanced regional resolution (dividing Japan into 129 regions) to analyze future energy supply and demand at the regional level. The model explicitly takes into account the national power grid and has a structure that allows for analysis of the construction of a nation-wide infrastructure as well as regional energy supply and demand. In addition, we estimated the possible installation area or resources of photovoltaic power generation, solar thermal, and wind power generation (onshore and offshore) at the municipal level across Japan, mainly for use as input data for the NE_JapanRegion model. A unique feature in the estimation of the three onshore technologies is the consideration of land competition. Second, for the input-output model, we conducted energy technology assessment and examined the development of a simulation model using the Renewable Energy Sector Focused InputOutput model for Region (REFIO-Region), which can be analyzed at the municipal level (1741 basic municipalities) in Japan. In the technology assessment, we performed analyses to understand the regional benefits that would result from the introduction of renewable energy technologies. For example, it was quantitatively revealed in which industries and regions the introduction of such technologies would create and conversely lose jobs. In addition, using hydrogen and offshore wind power generation as case studies, we analyzed the impact on regional economies in time series and gained insight into the development of a simulation model from the results. Third, as a preliminary study for developing a scenario analysis method, we collected future regional visions (scenarios) of decarbonization from various administrative information in Japan and attempted to analyze their unique features from multiple perspectives. The results suggest that while regional characteristics are not necessarily incorporated into the future visions, similar features can be found in the future visions of regions with common regional characteristics.