The societal benefit of electric vehicles depends heavily on how they interact with the electric power system. In this thesis, I investigate the impact of electric vehicles based on this interaction in order to determine the possible benefits of controlling electric vehicle charging and how they compare to other vehicle options based on optimization models of electricity systems. I estimate the cost reductions from controlled charging of electric vehicles in the New York power system both with and without a high wind penetration and with and without the need for capacity expansion. In this power system, controlled charging can reduce the generation costs associated with charging the vehicles in half, with slightly higher cost reductions in ...