Effects of Plug-In Hybrid Electric Vehicles on the Vermont Electric Transmission System

Plug-in hybrid electric vehicles (PHEVs) have emerged as a near-term technology to reduce the nation’s dependence on imported petroleum, address rising gasoline prices, and reduce carbon emissions from the transportation sector. This paper presents the results of a PHEV grid impact study for the State of Vermont—a small power system with peak demand of approximately 1 GW. The study looked at three different PHEV penetration rates and three different charging scenarios. Uncontrolled charging regimes even at a low PHEV penetration rate of 50,000 vehicles ( ~ 9 % of the Vermont light duty vehicle fleet) could lead to an increase in the peak demand for electric power in Vermont. However, a delayed nighttime charging regime could accommodate 100,000 PHEVs without adding to system peaks. Furthermore, next generation smart grid technology using optimal charging algorithms could accommodate 200,000 PHEVs, or approximately one-third of Vermont LDVs. As previous studies have found, displacing conventional ICE vehicles with PHEVs can reduce GHG emissions and decrease consumer fuel costs