DAY-AHEAD UNIT COMMITMENT MODEL CONSIDERING CO2 EMISSION CONSTRAINT FOR MICROGRIDS

Abstract

Microgrid consists of conventional generators, renewable energy sources, and energy storage devices. Microgrids could operate in either grid-connected or islanded modes, depending on technical and economic characteristics. This paper demonstrates mixed-integer quadratic programming-based formulation for the optimization of the day-ahead unit commitment in the microgrid. The goal function is to minimize the total operational cost combined with the expenses incurred by the CO₂ emissions generated. The weighted sum approach is deployed to cope with the two-objective optimization problem. The optimization model considers constraints of power generation-consumption balance, generating unit-related restrictions, bounds of discharge/charge power, and energy level of energy storage devices. The computational model for a 24-hour day is divided into 24-time steps (each step with a one-hour time span). The proposed optimization model is evaluated using the CPLEX optimization solver within the GAMS programming environment. The calculation results demonstrate that integrating CO₂ emissions into the proposed optimization formulation has a considerable impact on the operational scheduling of generators in the microgrid.