Electric Car Mythbusting: Even With a “Long Tailpipe” of Emissions, EVs Are Cleaner

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As a typical American driver considers trading in a gas-powered auto for an electric vehicle and starts doing some research, they’re going to come across a number of myths and misinformation. In some instances, it’s mere misunderstanding of new technologies and energy systems. But in many cases, this is deliberate deception coordinated and underwritten by the oil and gasoline interests that stand to lose the most if and when electric cars pick up considerable market share.

One of the most common categories of EV mythmaking is to attack them for the very reasons many consumers are considering them in the first place—their inherent environmental benefits. In this first series of EV mythbusters, we’ll review the five ways that electric cars are attacked on environmental grounds, finding the roots of the deception, then debunking each thoroughly with substantiated science and data.

Myth #1: “Electric vehicles still run on fossil fuels, and therefore offer no benefit to the environment. They just move the emissions elsewhere, from the car’s tailpipe to a power plant’s smokestack.”

This is perhaps the oldest myth about EVs, having earned its own coined phrase “the long tailpipe.”

It was first debunked decades ago with plenty of research that helped shape the California Air Resources Board’s (CARB) policies in the early 1990s, but it keeps resurfacing in various forms as more of the public is exposed to electric cars.

The seed of this myth is that a significant portion of electricity is still generated by fossil fuels, which emit greenhouse gases and other air pollution. That EVs are often charged off of an electric grid with some degree of fossil fuel production is mostly true. However, this ignores some critical details.

First, the percentage of fossil-born electricity transmitting over the grid has been falling steadily for decades and the percent of low carbon, renewable resources is increasing. Gasoline-powered cars, of course, still and always will run entirely off of fossil fuels, and will always have unmitigated tailpipe emissions.

This alone makes “The Long Tailpipe” myth a fallacy of logic known as false equivalence, where two things may on the surface seem to be the same or equal, but a closer examination makes clear that they are not.

The bottom line is that EVs emit fewer greenhouse gases than their gas-powered equivalents, regardless of where and how they are charged. (This doesn’t even get into the improvements in local air quality, which are obviously enormous, given that EVs don’t even have tailpipes.) 

When we dig a little deeper into the latest research, we see that how big the greenhouse gas benefit is depends on where one lives and charges, as grid power distribution is regional in nature.

Yes, where you charge matters. Though even in the most coal-dependent parts of the grid in the Midwest, the greenhouse gas benefits of driving an EV are clear. Credit: Union of Concerned Scientists.

The latest analysis by the Union of Concerned Scientists (displayed in the map above) shows that an EV has an global warming emissions equivalent of a gas-powered car that gets no less than 38 mpg. Contrast this with a 29 mpg average for a compact/midsize internal combustion vehicle.  On the top end, EVs emit the same amount of greenhouse gases as a gas-powered car that gets 100 mpg. This results in an average of over 80 mpg for an electric car that charges off of the grid in the United States.

For its analysis, the UCS included both the generation of electricity and the refining of petroleum, so that is was a true apples-to-apples comparison (otherwise known as “well-to-wheels”) for both types of vehicles. The researchers also used an average efficiency EV and a sales-weighted average for EVs to determine the national average.

Some have argued that 29 mpg used as a comparison in the UCS report, while typical for an average small or medium sized car, is not a fair comp, as many hybrid gasoline vehicles greatly exceed that efficiency—with several now in the 50 mpg range. In response to that objection, UCS released a new analysis that looks at several of the most efficient EVs using the same map as before, rather than just an average efficiency EV. In keeping this apples-to-apples comparison, the results are definitive: In 95% of the country, an efficient EV is lower in emissions than even the most efficient hybrids.

Another important consideration is that EVs use energy more efficiently. By comparing the raw energy used to power the engine or motor and propel the vehicle, electric cars are between three and four times more efficient. More of the energy that is put into an electric vehicle is converted to propulsion, and less is loss as heat from combustion and other inefficient factors in internal combustion vehicles.

Thus, there are significant gains that drivers can achieve by pairing the inherent efficiencies of EVs with the ongoing greening of the grid. Not only do EVs emit less now than their internal combustion counterparts, but they will continue to be even cleaner as time goes on and the grid decarbonizes. Gasoline vehicles just can’t compete on an energy saving basis, and also tend to get dirtier and less efficient as they age, as the engines and emission systems no longer perform as they do when new.

In the next post in this series, we’ll tackle the myth—which has been surfacing a lot recently—that the manufacturing of EVs and their batteries contribute more to climate change than gas-powered vehicles. Spoiler alert: it’s not true.