UC Davis Institute of Transportation Studies

Accelerating the adoption of plug-in electric vehicles (PEVs), is critical to reduce GHG emissions in the light duty vehicle sector. Conventional PEV usage and GHG assessments are largely based on assumptions drawn from stated preferences and choice experiments of potential or current PEV owners, or self-reported travel and refueling diaries of mainstream internal combustion engine(ICE) users. This dissertation focuses on observed behavior of current PEV users. I present three studies that seek to improve our understanding of PEV driving and charging typified by two levels of disaggregation- vehicle level and household level.

First study develops an analytical procedure to quantify what aspects of driving and charging behavior contributes to the gap between observed PHEV Utility Factors and Society of Automotive Engineers (SAE) J2841 expectations. Results indicated that depending on the PHEV range, roughly ±45% of deviations is attributable charging behavior. Daily mileage was responsible for -20% to +3% of deviation. Annual mileage and effective charge depleting range achieved on-road influenced the UF deviation by ±25% and -20% to -4% respectively.

In the second study, driving and charging behavior differences between short-range (20 miles or less) and long-range (35 miles or more) PHEVs are investigated. It was found that diversity of charging locations is positively associated with electric miles from short-range PHEVs whereas encouraging more home charging increases the electrification benefits of longer-range PHEVs.

Third study quantifies the well-to-wheel GHG mitigation potential of Nissan Leaf, Chevrolet Bolt and Tesla Model S at the household level using a multi-year actual usage data from 73 two-car (single BEV and single ICE) California households. Analysis shows that on average 25% of Leaf and Bolt, and 30% of Tesla household’s GHG can be reduced from their current levels by driving the BEV instead of the ICE. Upgrading to a longer-range efficiency oriented BEV and fully charging overnight can mitigate an additional 10-15% household GHG. Upgrading to longer-range sportier performance oriented BEV nearly offset the GHG abatement benefits, but it electrifies the highest share of household miles.