The mitigation of gas dependence can basically be carried out by increasing fuel diversification in power generation, which is mostly through a long-term electric capacity expansion planning. In short term, fuel diversification might not fully be effective as the power utility is basically constrained by its less flexible existing generating facilities and obligation of power purchases from third party (Constello, 2005). Considering the possibility of high oil price in the foreseeable future, we consider improving the heat rate of existing gas fired power plants, which is a manageable strategy for power utilities, in the following scenario as a mitigation of the problem in short and medium terms.