An optimal scheme assists the municipalities in Fukuoka, Japan in achieving their goal of 100% renewable energy supply and future decarbonization

To achieve the net-zero greenhouse gas emissions goal by 2050, it is essential for local municipalities to clarify the current state of renewable energy (RE) development, energy balance, and future development directions. Thus, an optimal energy supply system scheme with a coordination function between municipalities has been designed for Fukuoka Prefecture. We initially examined the spatial distribution of current RE supply and energy balance at the municipality level and estimated the total supply potential of Agri-Voltaic to be approximately 4145 GWh year⁻¹. In our analysis, we found that in 2020 (the current scenario), the share of RE supply by municipalities relative to demand ranged from 3 % to 267 %, with an average of 32 %. Grid power accounted for 84 % of the total demand. However, considering factors like a declining birth rate, an aging population, and energy saving initiatives assumed for 2050 (the future scenario), we estimate a decrease in total energy demand from the current level of 30,950 to a future level of 24,339 GWh year⁻¹. From an emissions perspective, optimizing the promotion of additional RE sources and coordinating RE usage between municipalities in the future will help achieve the goal of 100 % RE supply, meet the future energy demand at the prefecture level, and support regional decarbonization efforts (emission reductions: 7871 GgCO₂).