Study on Greenhouse Gases Emissions Due to Fossil Fuel Consumption in Intercity Transportation Sector and Estimate the Reduction of External and Social Costs with Respect to Switching Natural Gas (Case Study: Zanjan City)

Transportation sector is the major consumer of oil products. Since consumption of gasoline has increased during the recent years, pollution of air and warming up of the earth as result of the production of green house gases, has increased. Natural gas, due to its environment friendliness as one of its characteristics, can become the dominant fuel in the transportation sector. In this study, we have evaluated the amount of Green House Gases produced from transportation sector using Clean Development Mechanism formuala. Then external and social costs from produced Green House Gases, the economies of the owner`s and governmental view and the present capacity of CNG stations to replace the CNG for other conventional fuels in zanjan city, were studied according to the variety of sceneries (increasing amount of bi-fule vehicles 25%, 50%, 75%, 90%, respectedly). The results show that the most amount of Greenhouse Gasses (GHGs) belong to the vehicles with conventional petrol engines which exceeds 2.08×1011 CO2 tonnage in a year imposing external and social costs which amount to $2.9×1012 and $1.6 ×1012, respectively, in just one single year. The least amount of (GHGs) belong to the CNG fueled vehicles with 3.4×109 CO2 tonnage in a year imposing external and social costs that would be $1×1010 and 1.4 ×1011, respectively, in just one single year. This study implies that the cost is mounting up, in the owner`s and governmental view. The present capacity of CNG stations to replace the CNG for other conventional fuels is just suited to the existing conditions in this city and the number of bi-fuel vehicles, but in other sceneries which requires that the city must be provided with other stations, should be disused in an independent study.