Events

Presenter: Brandon Marshall, MS, Sustainable Systems/MBA

Adviser: Gregory Keoleian

Summary: Plug-in hybrid electric vehicles (PHEVs) use grid electricity as well as on-board gasoline for motive force. These multiple energy sources make prediction of PHEV energy consumption challenging and also complicate evaluation of their potential impacts on the environmental sustainability and resilience of the larger systems in which they operate. This two-part thesis explores methods designed to aid in the assessment of these impacts in the context of dynamically coupled infrastructures.

Part 1 assesses of the environmental sustainability of PHEVs through a novel energy consumption modeling approach and compares it to a second approach from the literature, each using actual trip patterns from the 2009 National Household Travel Survey (NHTS). The first approach applies distance-dependent fuel efficiency and on-road electricity consumption rates based on naturalistic, or real world, driving information to determine gasoline and electricity consumption. The second uses consumption rates derived in accordance with government certification testing. The two PHEV models show agreement in electricity demand due to vehicle charging, gasoline consumption, and life cycle environmental impacts. The naturalistic drive cycle approach is explored as a means of extending location-specific driving data to supplement existing PHEV impact assessments methods.

Part 2 explores potential improvements to system resilience through the introduction of plug-in electric vehicle (PEV) technologies and associated adaptive behavioral responses. It examines vehicle electrification and trip prioritization as physical and behavioral determinants of transportation system resilience during a gasoline supply disruption, using NHTS data. Realized Travel Factor, the ratio of completed to demanded travel, is defined as an indicator of resilience. Simulations using the overall population indicate trip prioritization improves resilience more than PEV adoption at lower levels of electrification (below 20 mile electric range), although household-level results vary according to fleet size and travel demand. While 67% of households require no adaptive change during a five-day disruption, additional households are able to complete all high-priority trips through trip prioritization (+12%), PEV adoption (+14%), or a combination of both (+23%).