How Much on Electric? Looking at PHEV Users' eVMT and How It Might Change--Possible influence of CD Range, Charging Infrastructure, Vehicle Design and Self-selection

Since plug-in hybrid electric vehicles (PHEVs) operate in two different energy use modes, establishing how much electric travel is possible with a given charge depleting (CD) range is important to properly account for the environmental benefits and petroleum displacement potential of PHEVs. However, given the flexibility of the PHEV drivetrain, a number of factors will shape which vehicles consumers purchase and how the PHEV is used. Current methods for estimating the electric vehicle miles traveled (eVMT) potential of a given PHEV focus on assumptions for charging frequency and single day driving diary data. To estimate the potential implications of added workplace, public and DC fast charging infrastructure on the fraction of (eVMT) consumer PHEV-conversion usage patterns recorded during a vehicle demonstration project are combined with an energy and infrastructure model. The results show that charging infrastructure can increase the fraction of eVMT driving considerably (up to 15 percentage points) but, the benefit varies considerably by household and vehicle CD range. DC fast charging is shown to provide the most benefit of any away from home charging for PHEVs with 70 or more miles of CD range, but the use of fast charging by PHEV consumers will be sensitive to price and time tradeoff considerations. Further analysis of the utility factor (UF) results shows that household’s EV driving experience will vary considerably from the average, which highlights that using a fleet-wide utility factor to plan optimal PHEV ranges will lead to over and under estimates of CD range and battery size requirements for PHEV consumers.