Data Sources and Assumptions for the Electricity Sources and Emissions Tool

The following data sources and assumptions were used to calculate the emissions, fuel use, and electricity sources for conventional and electric-drive vehicles in the Electricity Sources and Emissions Tool.

Electricity Sources

These assumptions were used to show electricity sources.

Parameter Value Source
Electricity fuel mix varies U.S. Energy Information Administration's Open Data API for Electricity Net Generation. Updated annually based on data for the previous year.

Annual Vehicle Emissions

These assumptions were used to calculate the annual vehicle emissions for an average conventional, hybrid electric, plug-in hybrid electric, and 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.
Conventional vehicle mpg 24.3 CAFE Standard
HEV mpg 44.4 Weighted average of 2016 model year vehicle sales in 2015 from U.S. HEV Sales by Model and mpg values from the 2016 Fuel Economy Guide.
PHEV mpg 37.9 Weighted average of 2016 model year vehicle sales in 2015 from U.S. Plug-in Electric Vehicle Sales by Model and mpg values from the 2016 Fuel Economy Guide.
PHEV kWh/mi 0.367 Weighted average of 2016 model year vehicle sales in 2015 from U.S. Plug-in Electric Vehicle Sales by Model and mpg values from the 2016 Fuel Economy Guide.
PHEV all-electric range 33 Weighted average of 2016 model year vehicle sales in 2015 from U.S. Plug-in Electric Vehicle Sales by Model and mpg values from the 2016 Fuel Economy Guide.
EV kWh/mi 0.32 Weighted average of 2016 model year vehicle sales in 2015 from U.S. Plug-in Electric Vehicle Sales by Model and mpg values from the 2016 Fuel Economy Guide.
Percentage of PHEV annual miles driven on electricity 55% Estimate based on SAE J2841 assuming the PHEV all-electric range is 33 miles.
Average annual vehicle miles driven 11,824 Transportation Energy Data Book Edition 34, Table 8.1 (total vehicle miles traveled divided by vehicles in operation), 2013