Hybrid and Plug-In Electric Vehicle Emissions Data Sources and Assumptions

The following sources and assumptions were used to calculate the emissions, fuel use, and electricity sources for conventional and electric drive vehicles on the hybrid and plug-in electric vehicle emissions page.

Electricity Sources and Annual Vehicle Emissions

The following sources and assumptions were used to show electricity sources and calculate the annual vehicle emissions for a conventional, hybrid electric, plug-in hybrid electric, or all-electric vehicle.

Parameter Value Source
Pounds of CO2e per gallon of gasoline 23.5 Full fuel cycle (well to wheels) greenhouse gas emissions (GHG) factors derived from GREET 2015. Results in CO2 equivalents (model available at http://greet.es.anl.gov)
National average electricity GHG/kWh 0.00 Energy Information Administration, Electricity Net Generation, Open Data, API http://www.eia.gov/opendata/qb.cfm?category=1
Electricity fuel mix varies Energy Information Administration, Electricity Net Generation, Open Data, API http://www.eia.gov/opendata/qb.cfm?category=1
Conventional vehicle mpg 24.3 CAFÉ Standard
HEV mpg 44.4 Sales weighted average of 2016 model year vehicles with sales in 2015: 2015 sales from "U.S. HEV Sales by Model" (http://www.afdc.energy.gov/data/vehicles.html); MPGs from 2016 Fuel Economy Guide (https://www.fueleconomy.gov/feg/)
PHEV mpg 37.9 Sales weighted average of 2016 model year vehicles with sales in 2015: 2015 sales from "U.S. Plug-in Electric Vehicle Sales by Model" (http://www.afdc.energy.gov/data/vehicles.html); MPGs from 2016 Fuel Economy Guide (https://www.fueleconomy.gov/feg/)
PHEV kWh/mi 0.367 Sales weighted average of 2016 model year vehicles with sales in 2015: 2015 sales from "U.S. Plug-in Electric Vehicle Sales by Model" (http://www.afdc.energy.gov/data/vehicles.html); MPGs from 2016 Fuel Economy Guide (https://www.fueleconomy.gov/feg/)
PHEV all electric range 33 Sales weighted average of 2016 model year vehicles with sales in 2015: 2015 sales from "U.S. Plug-in Electric Vehicle Sales by Model" (http://www.afdc.energy.gov/data/vehicles.html); MPGs from 2016 Fuel Economy Guide (https://www.fueleconomy.gov/feg/)
EV kWh/mi 0.32 Sales weighted average of 2016 model year vehicles with sales in 2015: 2015 sales from "U.S. Plug-in Electric Vehicle Sales by Model" (http://www.afdc.energy.gov/data/vehicles.html); MPGs from 2016 Fuel Economy Guide (https://www.fueleconomy.gov/feg/)
Percentage of PHEV annual miles driven on electricity 55% Estimate based on the current industry standard, SAE J2841 (available in http://avt.inel.gov/pdf/EVProj/EVProjectUtilityFactorVolt.pdf), assuming the PHEV all-electric range is 33 miles.
Average annual vehicle mileage (miles) 11,824 Transportation Energy Data Book #34 (http://cta.ornl.gov/data/download34.shtml), Table 8.1; Total vehicle miles traveled divided by vehicles in operation, 2013