Sources and Assumptions for the Electric and Plug-in Hybrid Vehicle GHG Emissions Calculator
To estimate your CO2 emissions rates and generate the bar graph, we used the following sources and assumptions.
| Your CO2 Emissions Rates | ||
|---|---|---|
| Tailpipe (grams CO2/mile) | This is the tailpipe CO2 emissions rate for combined city and highway driving that is shown on the fuel economy and environment label for the vehicle model you selected. It is the same regardless of where you live. | |
| Total (grams CO2/mile) | This includes the vehicle's tailpipe emissions and emissions associated with the production of electricity used to charge the vehicle. For plug-in hybrid electric vehicles, it also includes emissions associated with the production of gasoline. It is estimated using the sources and assumptions below, and will vary based where you live. | |
| Electricity Assumptions | ||
| Power Plant Emissions (lb/MWh) | CO2 emissions rates (lbs/MWh) for 26 U.S. regions are taken from the Emissions & Generation Resource Integrated Database (eGRID2010 Version 1.1). EPA's Power Profiler ZIP Code Tool (Version 3.2) is used to map the user's zip code to the appropriate region. Click here for more information. | |
| Transmission & Distribution Losses | Some electricity is lost as it travels from the power plant to where it is used by the consumer (e.g., at the outlet). To adjust for these transmission & distribution losses, we apply five regional grid loss factors from eGRID2010 Version 1.1. | |
| OtherEmissions | Regional CO2 emissions rates are multiplied by a national average factor of 1.06 to account for greenhouse gas emissions associated with the production of feedstock used to generate electricity, e.g., emissions due to mining coal and transporting it to the power plant. (See 75 FR 25437, May 7, 2010) | |
| Gasoline Assumptions | ||
| Combustion Emissions | On average, 8,887 grams of CO2 are emitted from burning one gallon of gasoline. | |
| Production Emissions | Tailpipe CO2 emissions are multiplied by a national average factor of 1.25 to account for emissions associated with gasoline production, e.g., drilling, refining, and transportation, etc. (See 75 FR 25437, May 7, 2010) | |
| Percentage of electric operation | For electric vehicles, 100% of miles driven are powered by electricity. For plug-in hybrid vehicles, we assume 64% of the vehicle's operation is powered by electricity. | |
| Bar Graph | ||
| Your Results for this Vehicle | Displays the total CO2 emissions for the vehicle model you selected in your region of the country. | |
| National Average for this Vehicle | This is an estimate of the total CO2 emissions rate for the vehicle model you selected using a national average electricity emissions factor from eGRID2010 Version 1.1 and assuming a 6.156% loss during transmission & distribution. The other assumptions are the same as above. | |
| Average Vehicle | This is the estimated total CO2 emissions for the "average vehicle" as shown on the fuel economy and environment label. This gasoline-powered vehicle has a fuel economy of 22 mpg. A factor of 1.25 is applied to account for emissions from the production and transportation of gasoline. | |