Electric vehicles (EVs) themselves emit no greenhouse gases (GHGs), but substantial emissions can be produced “upstream” at the electric power plant.
Upstream emissions for any particular EV will vary greatly depending on where and when the vehicle is charged.
Upstream emissions will be higher in areas where electricity is generated primarily from burning coal, lower when natural gas is used, and near zero when it is produced from nuclear, hydro-electric, wind, or solar power. Many areas get power from several sources, and the percentage of electricity produced from "clean" power can vary by season and even by time of day.
EPA is in the process of developing a method for calculating a useful and meaningful estimate of upstream greenhouse gas emissions for consumers. We will provide these estimates on fueleconomy.gov as soon as they become available.
The diagram below shows the fuel mix used to produce electricity in each state. This may differ from the mix prevalent for your local utility.
Net Electricity Generation by State and Fuel Source, 2009 (Gigawatt-Hours)
Source: Department of Energy (DOE) Energy Information Administration (EIA), Electric Power Annual 2009 - State Data Tables, 1990-2009 Net Generation by State by Type of Producer by Energy Source (EIA-906, EIA-920, and EIA-923).