Evaluation of Adequacy and Flexibility of Interconnection in case of Japan with over 90% Renewable Electricity Ratio in FY2040

Japan faces the dual challenge of maintaining energy security while achieving deep decarbonization of its power sector. As a G7 country, Japan must decarbonize electricity supply by around 2035; although nuclear restarts are cost-effective, their contribution is expected to remain limited in FY 2040. Consequently, most electricity demand must be met by renewable energy, and previous studies show that systems with 90% renewables can achieve lower generation costs than 40–50% renewable scenarios when sufficient flexibility is available.