The Ludicrous “Long Tailpipe”
Accusation by Petrolpuppets

Mark D Larsen

I cannot tell you how many times I have heard the old, worn-out “long tailpipe” argument against electric vehicles, i.e., that they are more harmful than gasoline cars on the environment because they get their electricity from dirty coal-fired power plants “upstream” that are belching out emissions from their smokestacks. I swear to Gaia that it seems like every time an article, blog, forum, tweet, video, or news release mentions an electric car lately, petrolpuppets immediately jump on it and post derisive comments with that same broken-record accusation. Of course, those naysayers never respond when an EV advocate then takes the time and effort to clarify the misconception by reminding them that gasoline does not magically appear at the pump: oil companies use those same power plants “upstream” to drill, extract, ship, refine, transport, and pump the fuel before it is ever burned in a car’s internal-combustion engine, producing even more greenhouse gas (GHG) emissions.

I have grown so weary, so fed up, so sick-and-tired of these trolls that I decided to compile the following comparison, using verifiable numbers, so that in the future I can simply refer readers exposed to such petrolganda to this web page. To accommodate the petrolparrots, I have used a rudimentary format that progresses through the calculations step-by-step —a sort of “Vehicle Emissions for Dummies.”

The Electric Grid in the United States

In reality, coal-fired power plants now generate less than half of the electricity in this country. The following table lists the various types of power plants in our grid, the grams of GHG that they each produce per kWh, the percentage of the grid that they represent, and the subsequent amount of GHG produced per kWh:

grams GHG
per kWh
percent of
U.S. grid
proportional grams
GHG per kWh
Coal 1,050 44.90% 471.45
Natural Gas 443 23.40% 103.66
Nuclear 66 20.30% 13.40
Petroleum 778 1.00% 7.78
Hydroelectric 10 6.90% 0.69
Wind 10 2.30% 0.22
Solar 23 1.00% 0.23
Other Renewables 23 0.20% 0.05
TOTAL: 100.0% 597.47

According to the Greenhouse Gas Emissions Calculations of the EPA, under the heading “Electricity Assumptions,” it is also necessary to multiply the amount above by a factor of 1.06 to account for the additional emissions from “feedstock,” i.e., the extraction and transportation of the raw source materials to the power plants. Here is the result when we apply that factor:

proportional grams
GHG per kWh
EPA factor for
“feedstock” emissions
per kWh in U.S.
597.47 1.06 633.32

As the total shows, the electric grid in this country actually generates only 57% of the amount of GHG that would be produced by purely coal-fired power plants, i.e., significantly less than petrolpuppets would lead us to believe with their blanket statements.

Finally, because we commonly use pounds rather than grams in this country, we can render that total more understandable for U.S. readers by applying the standard conversion formula to determine the average number of pounds of GHG per kWh that the national grid produces.

per kWh in U.S.
pounds-per-gram TOTAL lbs. GHG
per kWh in U.S.
633.32 0.002205 1.3965

Nissan Leaf Electric Vehicle

The EPA has recently posted an interactive tool on its website that allows drivers to estimate the amount of emissions generated upstream to charge an electric vehicle in their particular area of the country. The tool’s pop-up menu for “Vehicle Model” lists the EVs currently available, and will undoubtedly include more plug-in vehicles as they enter the market in the future. If, for example, I enter my zip code in the box, select the year 2013, and designate the Nissan Leaf, the tool calculates that charging it from the grid would produce 150 grams of GHG per mile “upstream.”

The EPA’s same page cited above on Greenhouse Gas Emissions Calculations explains these calculations. Under the heading “Electricity Assumptions,” the EPA states that the amount of GHG per zip code comes from its Emissions & Generation Resource Integrated Database (eGRID2010 Version 1.1), which not only includes the “feedstock” emissions mentioned above, but also the “transmission and distribution losses” as the electricity “travels from the power plant to where it is used by the consumer.”

Whatever zip code one enters with this tool, it also reports the electric vehicle’s national average of GHG emissions. In the case of the 2013 Nissan Leaf, that amount is 190 grams per mile nationwide. It is thus a simple formula to determine the amount of GHG produced “upstream” per 100 miles driven.

grams GHG per mile miles driven grams GHG per 100 miles
190 100 19,000

Finally, to again render the total in more commonly understood units of measurement, we can apply the standard pounds-per-gram formula.

grams GHG per 100 miles pounds-per-gram lbs. GHG per 100 miles
19,000 0.002205 42

Nissan Versa Gasoline Car

The EPA has also recently started providing “upstream” emission figures for gasoline vehicles on its website, under the tab labeled “Energy and Environment” —as exemplified on the page for the 2013 Nissan Versa. Clicking on that tab will open a page with a pop-up menu to display only tailpipe GHG or both tailpipe and upstream emissions. The tailpipe figure for the Versa is 254; the upstream figure is 63.

The same page on Greenhouse Gas Emissions Calculations also clarifies the math behind these numbers. Under the heading “Gasoline Assumptions,” the EPA states that burning one gallon of gasoline produces on average 8,887 grams of GHG from a vehicle’s tailpipe. It also states that, to determine the upstream emissions to produce the gasoline, it is necessary to multiply the tailpipe amount by a national average factor of 1.25.

tailpipe grams
GHG per gallon
EPA factor for
“upstream” emissions
TOTAL grams
GHG per gallon
8,887 1.25 11,109

Since the EPA gives the Versa a combined fuel economy rating of 35 mpg, we can multiply the grams of GHG per gallon to determine the total amount per 100 miles:

TOTAL grams
GHG per gallon
gallons per 100 miles grams GHG per 100 miles
11,109 2.857 31,738

Finally, to once again express that amount in more understandable terms, we will apply the usual pounds-per-gram formula.

grams GHG per 100 miles pounds-per-gram lbs. GHG per 100 miles
31,738 0.002205 70

As the above figures clearly show, an electric vehicle (with its so-called “long tailpipe”) produces less GHG than a comparable gasoline vehicle (with the very same “long” tailpipe and another “short” one on the back of the car). According to my calculator, one is always less than two.

Another important point is that the vast majority of owners charge their EVs at home during the night while asleep, when the electric demand is the lowest and the rates are the cheapest. Consequently, contrary to another petrolpuppet accusation, EVs will not “overload” the grid, which has more than enough capacity to charge them during those off-peak hours. In fact, although power plants throttle back at night, they cannot shut down completely, and thus at least some of that energy ends up unused. Since those “long tailpipes” are smokin’ away anyway, would petrolpuppets prefer to let those electrons go to waste rather than put them to good use for transportation?

Finally, there is little doubt that, unlike with fossil fuels, the electric grid will only get cleaner over time, as more renewable energy sources like solar, wind, geothermal, and hydro supplant coal. Indeed, if one charges an electric vehicle with solar panels like mine, it produces zero emissions.

Conversely, you can’t generate gasoline on your roof.

Utility to Compare “Tailpipes”

I used the above comparison simply because Nissan designed the Leaf as a variation on the Versa platform, and thus they are the most comparable in terms of size, style, dimensions, and capacity. However, a few EV advocates have asked how the GHG emissions of other vehicles might compare. To accomodate such requests, I have programmed a simple utility so that drivers can input the MPG of their current gasoline car and compare the results with those from a Nissan LEAF in their specific utility region.