The main objective of this work is to estimate the carbon dioxide (CO₂) emissions from natural gas-fired combined cycle gas turbine (CCGT) units in Libya and to integrate these estimations within an environmental power dispatch model that considers several power plants. The study begins with a preliminary design aimed at calibrating the model using the limited data provided by manufacturers. Off-design operating points are also investigated in order to estimate emissions across the full operating range of the units. The results show good consistency with emission coefficients reported in the literature for this type of units. Subsequently, carbon costs are used as input parameters in a Unit Commitment (UC) problem, where a Mixed Integer Linear Programming (MILP) formulation is applied to minimize the total emissions of a set of units within the Libyan power grid. The emission factors obtained for the simulated network display values close to the recorded field data, validating the developed model. Finally, a tightened formulation of the dispatch problem is introduced, aiming to reduce computational time while ensuring high-quality performance of the returned solutions. and Results show that prioritizing newer and more efficient plants reduces national emissions by 10–15%................. Keywords: ................Combined Cycle Gas Turbine, Design, CO₂ Emissions, Environmental Unit Commitment, Power Dispatch, Optimization.