One method of reducing atmospheric CO2 emissions in the transportation sector is the replacement of conventional fossil fuel-based vehicles with Electric Vehicles (EVs). However, fossil fuels are still the primary source of electricity production in many regions and the utilization of EVs in such regions increases the electricity demand because of battery charging. This results in increased burning of fossil fuels by thermal power plants and therefore can offset savings in CO2 emissions resulting from the adoption of EVs. In this paper, we consider a scenario where all fossil fuel-based conventional vehicles are replaced by EVs and then estimate the net CO2 emission savings resulting from the adoption of EVs in a region where electricity is primarily supplied by thermal plants. Only emissions generated during the operational phase of vehicle use are considered; emissions during the production phase are not considered. The region under consideration is Madeira, Portugal where thermal plants account for 80% of the total electricity produced. Our findings suggest that although EVs have huge potential to save CO2 emissions, a substantial amount of the savings can be offset due to the increased burning of fossil fuels by thermal plants to meet the electrical demand of charging batteries.