Addressing flexibility issues in clustered unit commitment formulations for generation expansion planning models

This work proposes a Clustered Unit Commitment (CUC) formulation to accurately model flexibility requirements such as ramping, reserve, and startup/shutdown constraints. The classic CUC intrinsically and hiddenly overestimates the individual unit’s flexibility, thus being unable to replicate the result of the individual UC. Different case studies show that the proposed CUC correctly represents the individual unit’s flexibility within the cluster and how it is applied to long-term planning models without significantly increasing their computational burden.