Aug 15, 2012Don Anair
The longer you own an electric vehicle, the lower its global warming emissions are likely to become. Why? As some of the oldest, dirtiest coal plants are being retired and investments in renewable electricity increase, the global warming emissions that result from generating a given amount of electricity are estimated to fall nationwide by an average of about 13 percent by 2025.
That means, for 70 percent of Americans, charging their electric vehicle (EV) on the regional electricity grid in 2025 would result in lower global warming emissions than even today’s most efficient gasoline hybrid, the 50 mpg Prius. While that’s good news, it could be even better. By investing in more renewables and retiring more coal plants over the next decade, using electricity as a transportation fuel would deliver even greater global warming benefits than projected.
How will changes in the grid affect the emissions from charging an EV?
To get an idea of how emissions from charging an EV may change in the coming years, I looked to the Annual Energy Outlook updated most recently in June of this year by the U.S. Energy Information Administration (EIA). The outlook projects changes in the electricity grid expected in the coming years as a result of varying energy demand, regulatory drivers, expected power plant retirements, and other factors.
Using the same well-to-wheels methodology used in our State of Charge report (more on this in the notes below), and the Annual Energy Outlook’s projections for 2025, I estimated how the emissions from charging an EV powered by the grid in 2025 compare to the emissions of a gasoline vehicle. I did this analysis across each of the grid regions across the United States, excluding Hawaii and Alaska for which projections were unavailable.
Don Anair is a senior engineer at the Union of Concerned Scientists with expertise on diesel, hybrid and battery electric vehicle, and goods movement technologies and the policies needed to turn them into real solutions for U.S. oil dependence, air pollution and global warming. He holds a master’s degree in electrical engineering.