Modeling Prospective Reserve Requirements: A Probabilistic Framework Applied to the French Power System

In the coming decades, balancing reserve requirements are expected to grow significantly due to the increasing share of variable renewable energy sources (VRES) in the power system. The uncertainty introduced by wind and solar generation must be balanced by flexible resources to maintain grid reliability. As a result, Transmission System Operators (TSOs) must not anticipate reserve needs well in advance in addition to monitoring them in real time. Prospective studies thus become a crucial tool to inform long-term planning decisions made now, ensuring the future system will be able to cope with rising flexibility needs. This challenge has been explicitly in the recent Flexibility Needs Assessment Methodology of