Fuel Economy Assumptions

For plug-in hybrid electric vehicles (PHEVs), the fuel economy is the combined utility-factor-weighted fuel economy averaged across charge-depleting and charge-sustaining modes. This is consistent with the results provided by Islam et al. (Islam et al., 2023). (The breakout of utility-factor-weighted average electricity and liquid fuel economy for plug-in hybrid electric vehicles is included the downloadable data.) The combined utility-factor-weighted fuel economy is calculated using this equation:

$$ \text{PHEV_FE [in mpgge]} = \dfrac{1}{\mathrm{UF} * \dfrac{\text{EC}_\text{CD}\text{[in Wh/mi]}}{33700} + \dfrac{1-\text{UF}}{\text{FE}_\text{CS}\text{[in mpgge]}}} $$

where

UF is the utility factor representing the fraction of miles traveled on electricity
EC_CD is the charge-depleting electricity consumption (in watt-hours [Wh]/mi)
FE_CS is the charge-sustaining fuel economy (in miles per gasoline gallon equivalent [mpgge]).

We convert Wh to gge assuming 1 gge = 33,700 Wh (EPA, 2011). Assumptions for utility factor are on the Levelized Cost of Driving Assumptions page.

References

The following references are specific to this page; for all references in this ATB, see References.

Islam, Ehsan Sabri, Daniela Nieto Prada, Ram Vijayagopal, Charbel Mansour, Paul Phillips, Namdoo Kim, Michel Alhajjar, and Aymeric Rousseau. “Detailed Simulation Study to Evaluate Future Transportation Decarbonization Potential.” Report to the US Department of Energy, Contract ANL/TAPS-23/3. Argonne National Laboratory (ANL), Argonne, IL (United States), October 2023. https://anl.app.box.com/s/hv4kufocq3leoijt6v0wht2uddjuiff4.

EPA. “New Fuel Economy and Environment Labels for a New Generation of Vehicles.” Washington D.C.: U.S. Environmental Protection Agency, May 2011. https://nepis.epa.gov/Exe/ZyNET.exe/P100BAV0.TXT?ZyActionD=ZyDocument&Client=EPA&Index=2011+Thru+2015&Docs=&Query=&Time=&EndTime=&SearchMethod=1&TocRestrict=n&Toc=&TocEntry=&QField=&QFieldYear=&QFieldMonth=&QFieldDay=&IntQFieldOp=0&ExtQFieldOp=0&XmlQuery=&File=D%3A%5Czyfiles%5CIndex%20Data%5C11thru15%5CTxt%5C00000001%5CP100BAV0.txt&User=ANONYMOUS&Password=anonymous&SortMethod=h%7C-&MaximumDocuments=1&FuzzyDegree=0&ImageQuality=r75g8/r75g8/x150y150g16/i425&Display=hpfr&DefSeekPage=x&SearchBack=ZyActionL&Back=ZyActionS&BackDesc=Results%20page&MaximumPages=1&ZyEntry=1&SeekPage=x&ZyPURL.