This paper studies the reduction in CO 2 resulting from synergistic interaction of PHEVs with an electric grid containing significant amount of wind power. A combined optimal charging and optimal power management approach is used to rigorously quantify the optimal CO 2 reduction impact. This approach produces results that show that inclusion of any amount of wind power on the grid results in reduced CO 2 from transportation. The results also account for the temporal variation in wind power. Furthermore, since it is not practical to implement a different control strategy for days with different amounts of wind, we quantify the loss of optimality resulting from this variability in wind.