Optimization Analysis of 100% Renewable Energy Chains Considering Energy Service Demands in Namie Town, Fukushima

Driven by the 2011 nuclear disaster, Namie Town, Fukushima, is aiming to implement a standalone 100% renewable energy system by 2035 using regional resources. This study clarifies the optimal configuration of a carbon-neutral energy system, focusing on hydrogen’s role as a final energy carrier. To achieve this, we developed a linear programming model integrating energy supply, storage, and service demands with hourly temporal resolution. This model determines the optimal installed capacities and hourly operation of all facilities to minimize the total annual system cost. Using this optimization framework, we quantitatively compared an “E case” (electricity supply only) and an “EH case” (combined electricity and hydrogen supply). The results indicate that the EH case optimizes facility capacity through appropriate role allocation between batteries and hydrogen. Specifically, in this case, the hydrogen power generation capacity decreased by 41.3% compared to that in the E case. Furthermore, avoiding hydrogen-to-electricity reconversion losses reduced the required renewable generation by 7.6%, leading to a 6.8% reduction in total system costs. These findings demonstrate that utilizing hydrogen as a flexible carrier connecting supply and demand—rather than merely as a storage medium—effectively achieves energy efficiency and economic viability in regional standalone energy systems.