This paper presents an LCA model to estimate the carbon footprint of a fossil fuel power plant for better policy implementation in an energy portfolio. The frameworks of the proposed model have integrated two groups of parameters (parameters affecting emissions and parameters affecting the amount of electricity) into one model. The model is developed to handle three types of power plants: gas turbine, combined cycle, and steam power with different fuel types and different utility transfer policies. The model is verified with two case studies in Iran. The results show good agreement between the model output and existing conditions.