"
U.S. 2013 Electricity Generation By Type.
[137]
An EV recharged from the US grid electricity in 2008 emits about 115 grams of CO
2 per kilometer driven (6.5 oz(CO
2)/mi), whereas a conventional US-market gasoline powered car emits 250 g(CO2)/km (14 oz(CO2)/mi) (most from its tailpipe, some from the production and distribution of gasoline).
[138]
The
Union of Concerned Scientists (UCS) published in 2012 a report with an assessment of average greenhouse gas emissions resulting from charging plug-in car batteries considering the full life-cycle (
well-to-wheel analysis) and the fuel used to generate electric power by region in the U.S. The study used the
Nissan Leaf all-electric car to establish the analysis's baseline. The UCS study expressed the results in terms of
miles per gallon instead of the conventional unit of grams of
carbon dioxide emissions per year. The study found that in areas where electricity is generated from natural gas, nuclear, or renewable resources such as hydroelectric, the potential of plug-in electric cars to reduce greenhouse emissions is significant. On the other hand, in regions where a high proportion of power is generated from coal,
hybrid electric cars produce less CO
2emissions than
plug-in electric cars, and the best fuel efficient gasoline-powered
subcompact car produces slightly less emissions than a plug-in car. In the worst-case scenario, the study estimated that for a region where all energy is generated from coal, a plug-in electric car would emit greenhouse gas emissions equivalent to a gasoline car rated at a combined city/highway fuel economy of 30 mpg-US (7.8 L/100 km; 36 mpg-imp). In contrast, in a region that is completely reliant on natural gas, the plug-in would be equivalent to a gasoline-powered car rated at 50 mpg-US (4.7 L/100 km; 60 mpg-imp) combined.
[139][140]
The study found that for 45% of the U.S. population, a plug-in electric car will generate lower CO
2 emissions than a gasoline-powered car capable of a combined fuel economy of 50 mpg-US (4.7 L/100 km; 60 mpg-imp), such as the
Toyota Prius. Cities in this group included
Portland, Oregon,
San Francisco,
Los Angeles,
New York City, and
Salt Lake City, and the cleanest cities achieved well-to-wheel emissions equivalent to a fuel economy of 79 mpg-US (3.0 L/100 km; 95 mpg-imp). The study also found that for 37% of the population, the electric car emissions will fall in the range of a gasoline-powered car rated at a combined fuel economy between 41 to 50 mpg-US (5.7 to 4.7 L/100 km; 49 to 60 mpg-imp), such as the
Honda Civic Hybrid and the
Lexus CT200h. Cities in this group include
Phoenix, Arizona,
Houston,
Miami,
Columbus, Ohio and
Atlanta, Georgia. An 18% of the population lives in areas where the power supply is more dependent on burning carbon, and emissions will be equivalent to a car rated at a combined fuel economy between 31 to 40 mpg-US (7.6 to 5.9 L/100 km; 37 to 48 mpg-imp), such as the
Chevrolet Cruze and
Ford Focus. This group includes
Denver,
Minneapolis,
Saint Louis, Missouri,
Detroit, and
Oklahoma City.
[140][141][142]The study found that there are no regions in the U.S. where plug-in electric cars will have higher greenhouse gas emissions than the average new compact gasoline engine automobile, and the area with the dirtiest power supply produces CO2 emissions equivalent to a gasoline-powered car rated 33 mpg-US (7.1 L/100 km; 40 mpg-imp).[139]"
