Representing Operational Flexibility in Generation Expansion Planning Through Convex Relaxation of Unit Commitment

Large shares of renewable generation in electric power systems increase the need for operational flexibility. Consideration of operational flexibility in generation expansion planning (GEP) necessitates the modeling of unit commitment (UC) in system operations. However, the UC problem itself is computationally challenging. We present a GEP model in which the embedded operational problem is a convex relaxation of the UC problem. Through a large-scale example based on the Texas system, we show the tightness and tractability of our relaxation, as well as the impact of operational flexibility on GEP.