This study presents the results on the simulations of the scenarios based on the CO2 emission reduction of the electricity sector in Turkey, utilising the long-range energy alternatives planning (LEAP) system model, and the mitigation costs of the scenarios. Three scenarios including baseline scenario, (scenario 1) and the two mitigation scenarios (scenario 2 and scenario 3) are employed. The scenario 1 is based on the continuation of the recent electricity generation composition. Scenario 2 is established for the evaluation of all the renewable energy potential, except solar, of Turkey while scenario 3 included all the renewable and nuclear energy. The CO2 emission intensity decreased by 20.5% and 35.6% for the scenarios 2 and 3 in 2030, respectively compared to the baseline scenario. The CO2 emission mitigation costs are found 17 $/ ton CO2 and 40 $/ ton CO2 for the Scenarios 2 and 3, respectively through 2010 to 2030.