Impact of diversified supply of flexibilities in the transition of a power system: Japan’s case study

In a transition to carbon neutral of a power system, a decline of traditional generation capacity in operation and an increase of variability and forecast error of photovoltaic (PV) and wind generation simultaneously cause a short of supply of balancing flexibility requirement. In the transition the best use of distributed energy resources (DER) such as PV, wind, activated demands, and batteries are possibilities for a power system so as to secure an affordable and stable energy utilization. For the study on a future flexibility supply, authors review the 7th Strategic Energy Plan which was published in February 2025 including “LCOE with a part of the integration cost” to set up a study scenario of the power market in Japan. In the study authors analysed, using demand and supply analysis of 8760 hours by “MR”, benefits of balancing flexibility supply from both traditional generators and emerging DER for Japan’s power system in 2040. The results imply that it is crucial to be ready for the utilization of flexibilities from DER through two aspects: the first is that diversified technologies such as dedicated batteries and activated demands with characteristics of different response time, energy limit (duration time) and certainty of control can share the requirements for balancing flexibility, The second is that the flexibility requirements should be continuously rationalized and minimized.