Electricity Emissions
Electric vehicles (EVs) emit no tailpipe pollutants. Therefore, they can provide huge air-quality benefits to targeted regions. However, pollutants emitted from the electrical power plants and other upstream operations must be accounted for. Argonne National Laboratory accounted for these pollutants and EV lifecycle emissions, along with conventional vehicles powered by reformulated gasoline (RFG) in the GREET model.
The following table lists ANL's emission findings and how much emissions would be reduced by replacing a conventional vehicle with an EV.
| Conventional Car on RFG | Electric Car | Percent Reduction (increase) | |
|---|---|---|---|
| Grams/Mile | Grams/Mile | ||
| Carbon Monoxide (CO) Total | 2.906 | 0.113 | 96% |
| CO: Urban | 2.767 | 0.005 | 100% |
| Volatile Organic Compounds (VOC) Total | 0.209 | 0.036 | 83% |
| VOC: Urban | 0.148 | 0.000 | 100% |
| Oxides of Nitrogen (NOx) Total | 0.212 | 0.778 | -267% |
| NOx: Urban | 0.048 | 0.015 | 69% |
| Particulate Matter 10 (PM10) Total | 0.047 | 0.077 | -64% |
| PM10: Urban | 0.032 | 0.022 | 31% |
| Sulfur Oxides (SOx) Total | 0.085 | 0.925 | -988% |
| SOx: Urban | 0.008 | 0.002 | 75% |
| Carbon Dioxide | 449 | 371 | 17% |
| Greenhouse Gases (GHG) | 473 | 384 | 19% |
| BTU/Mile | BTU/Mile | ||
| Fossil Fuels | 5827 | 4201 | 28% |
| Petroleum | 4573 | 89 | 98% |
Source: GREET Transportation Fuel-Cycle Model
* Lifecycle emissions account for primary fuel recovery, preparation, delivery, and use by the vehicle. They do not account for energy used to produce the vehicle.
The emissions reported in the table correspond to Argonne's "long-term" conventional car technologies, which meet Tier 2 emissions standards and use RFG. The emissions from power plants correspond to Argonne's "near-term" emissions from the fuel mix and locations of U.S. power plants in 2005. For more information, see the GREET Transportation Fuel-Cycle Model
Emissions in Urban Areas
The table illustrates that electric vehicles substantially reduce all the emissions that cause adverse health conditions in urban settings, where they can be concentrated and do the most harm to human health. Replacing a conventional vehicle with an EV reduces VOCs and CO by 100%, SOx by 75%, NOx by 69%, and PM10 by 31% in urban settings.
Total Emissions
Electric vehicles also reduce the total (urban and rural) CO emissions by 96% and VOCs by 83%. The reduction in rural VOCs is important because they, as primary contributors to ozone, can reduce crop yields and damage natural ecosystems.
It should not be overlooked, however, that electric cars can actually increase some overall emissions—particularly in rural areas. SOx emissions are increased almost tenfold by powering a car with electricity instead of gasoline. The same change in fuel also increases total NOx emissions by 267% and PM10 by 64%. The increase in rural SOx and NOx are of particular importance because they are the primary causes of acid rain.
Lifecycle GHG Emissions and Petroleum Use
The GREET report shows that EVs reduce greenhouse gas emissions by 19% and nearly eliminate petroleum use because U.S. electric power is not generally produced from petroleum. Electric cars reduce fossil fuel use by 28% despite the fact that electricity is largely generated by fossil fuels—a sign of good system efficiency. A more recent study, Full Fuel Cycle Assessment: Well-to-Wheels Energy Inputs, Emissions, and Water Impacts by the California Energy Commission, shows that with the electricity fuel mix in California, EVs reduce GHG emissions by 74%.