Authors used Long-range Energy Alternatives Planning (LEAP) model in this paper to develop and analyze future energy demand, production and CO2 emissions in Pakistan from 2020 to 2040. The model is developed based on Governmental Progressive Scenario (GPS), which forecasts sector wise (agriculture, commercial, domestic, industrial and others) energy demand of the country, and analyzes future energy supply pattern based on the domestic energy sources like RLNG, hydro, coal, natural gas, nuclear, furnace oil and renewable (wind, solar, biomass). The results of this study show that the growth rates of future energy supply and demand are 18% and 11% respectively. CO2 emissions based on future energy production are also forecasted from 2020 to 2040 which is showing declining trend due to the use of cleaner technologies in the future. The total cost of energy projects is also forecasted based on net present value at a discount rate of 4%, 8% and 12%. It is found that energy projects cost will be 50% less at discount rate of 8%. The results of this study are useful in making long term energy and environmental planning and policy formulation in Pakistan.