Holes in the Long Tailpipe

Dismantling the idea electric vehicles are not helpful to the environment.

Every time I hear someone argue that electrical vehicles (EVs) have no benefit because they only shift the point of pollution from the vehicle to the powerplant, I want to mock that person using the same voice that Eddie Murphy used in Beverly Hills Cop to say, “I’m not falling for the banana in the tailpipe.” You see, the Long Tailpipe hypothesis as it is called, is a very weak argument and I would like to tell you why.

The Long Tailpipe is merely a factoid–an idea repeated so often that it is assumed to be true. In short, the Long Tailpipe argues that powering an EV changes the energy source from one fossil fuel to another; from petroleum-based gasoline to coal, natural gas and petroleum which supply 70% of the power to the electrical grid [Wikipedia:Generation].

Let’s look at some counter-arguments that will dispel the Long Tailpipe theory.

It is true that switching vehicles from using a gasoline-based internal combustion engine (ICE) to an electric drivetrain shifts the energy demand from petroleum to the electrical grid. This, turns out to be a very good thing from nationalistic, economic and efficiency standpoints.

In the U.S.A., we currently import 58% of the petroleum that we use [EIA2008] at a cost of $350B – $700B per year [Pickens] and we use 70% of our oil for transportation [BTS]. Whereas the energy created for our electrical system comes from largely domestic sources. So switching from petroleum to electricity is buying local. Some argue that we don’t have enough domestic electrical energy to power all of our cars. That’s true for right now (we can only power 84% of them), but there are at least three plans to address this: The Pickens Plan, America 2050 and Better Place. Rather than argue about which plan is better, I simply assert that EVs can be made an integral part of our transportation system and breaking our dependency on foreign oil will keep a significant portion of our national wealth within our borders.

Efficiency is another reason the Long Tailpipe argument doesn’t hold up. The state-of-the-art ICE is at best 43% efficient [Wikipedia:ICE]. So only 43% of the energy in the gasoline is converted to mechanical energy at the engine’s output. This assumes the vehicle is in tip top shape, which is rarely the case. Most drivers do not perform standard maintenance on their vehicles and as a consequence operate below peak efficiency. Whereas state-of-the-art combined-cycle gas fired plants reach 50% efficiency [Wikipedia:FossilPower]. Furthermore, a power company achieves optimum profit by employing engineers and technicians to monitor and maintain the plants to run at peak performance so that fuel costs are minimized. So, more energy is derived from fuels burned in a power plant than in a number of ICEs burning the same amount of fuel.

A graph showing stopping power vs. brake pedal pressure of a Ford hybrid vehicle.

Ford hybrids recapture energy through regenerative braking

Regenerative braking puts the nail in the coffin of the Long Tailpipe. An EV can recapture a significant portion of its kinetic energy using regenerative braking; whereas a typical vehicle with an ICE loses its kinetic energy every time the brakes are used. While braking, kinetic energy turns into waste heat in the break pads and drum. This means an EV is going to inherently need less energy to go the same distance as an ICE vehicle in stop-and-go situations like typical city driving (assuming vehicles of equivalent mass). So even if coal were to maintain its current percent share of power generation, the use of EVs in place of cars with an ICE is going to be significantly more power efficient.

The last argument I make against the Long Tailpipe is one of perspective. To say that an EV will run on electricity made from mostly coal is to assume the electrical grid of today, rather than the electrical grid of the future when more EVs will be in service. Yes, coal is the major component of today’s electrical energy production and its use won’t go away overnight, let alone a decade. However, finite natural resources and future increases in demand for energy require that more renewable energy sources be developed and used as time passes. Austin Energy is thinking ahead and establishing a Renewable Portfolio Standard which sets a goal of using 20% renewable sources by 2020 [Strategic Plan p. 4]. Indeed, it should be a goal to grow both renewable energy and EV use across the U.S.A. simultaneously. Couple that with a nationwide push for reducing usage and increasing efficiency and we can have EVs that depend on clean renewable energy and still keep the A/C on during Houston’s summers.


Posted: Monday, April 5th, 2010 at 2:44 pm
Categories: featured, move
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3 Comments

  1. The problem with Dean Hall’s argument is he focuses on narrow aspects of environmental problems of automobile use. Hall needs to consider the entire carbon footprint associated w/ driving which includes the building, operating, and maintaining of a vehicle. When you consider 3/5 the amount of pollution created from an automobile (ICE or EV) comes from manufactoring the vehicle there is no such thing as a clean/grean ICE or EV. Just one example – the EPA estimates 50,000 gallons of water is polluted in the manufactoring of each vehicle. Another is the extraction of the heavy metals needed to create the EV power cells – the mining industry has been, and continues to be, one of the biggest environmental polluters.
    I agree there are some efficience standards attained with EV that are smart and heading in the right direction. But in the big picture of future transporation it is not sustainabile. If you want to make a difference and reduce your carbon foot print today consider the proven clean and grean modes like walking, biking, transit, and telecomuting.

    • Mr. Miller, Thank you for the feedback. I agree with your assessment of the negative impacts of vehicle manufacturing. My attempt in this article is to remove the few remaining defenses of those who are trying to justify continuing to use petroleum products in combustion engines by making claims like the long tailpipe. It takes a narrow focus of directed arguments to clear such FUD.

  2. 1. Regenerative braking is not limited to EVs. The Toyota Prius, a completely fossil fuel vehicle, has had it for over a decade.

    2. You left out electrical transmission losses as well as the loss inherent in cycling energy through a battery. Currently, the Leaf gets about 2/3rds the mileage of the Prius. (You have to divide MPGe by 3 to get the real MPGe – yes, the number is fudged that badly.)

    3. EVs are horrid in the winter. All that free heat from an ICE must be replaced with expensive resistance heat in an EV.

    4. The best ICEs get over 50%, not 43%. Single-speed diesels are way efficient.

    EVs will only make sense once the fossil fuel fleet is fully hybridized and the electrical grid is mostly de-carbonized. Until then, for a given quantity of batteries, it makes far more sense to make 10 hybrids than 1 EV. Obviously 10 Priuses, each of which gets 50MPG is better than 1 Leaf that gets perhaps 33MPGe in real life. And remember, hybrids can run off biofuels and synfuels, so the fossil fuel argument is very weak.

One Trackback

  1. A Short Tale & “The Long Tailpipe.” -- January 16, 2012 at 5:06 am

    [...] Once we allow this kind of argument, where do we stop the trail of blame? Other counter arguments have been proposed and I hope some will take the time to mention their impression of them in the comments section, [...]

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