Electric vehicles (EVs) and renewable energy (RE) are expected to increase in the path to achieving carbon neutrality. EVs with vehicle grid integration (VGI) can compensate for the fluctuation of RE to utilize RE more effectively and reduce fossil fuel consumption for thermal generation. This research aims to quantify CO₂ reduction from VGI using the demand and supply power system simulator and actual usage data of vehicles. Evidently, EVs with charge control (V1G) reduces 0.9 ton of CO₂ per EV per year and EV with charge and discharge control (V2G) reduces 1.9 ton of CO₂ per EV per year compared to non-controlled-charging. Additionally, the impact of VGI to EV battery degradation is quantified for the future improvement of VGI operation design to reduce CO₂ emissions and suppress battery degradation.