This blog post is the third in a new series by SACE volunteer Dave Erb intended to dispel some of the mis- and disinformation which dominate the public discourse about electric vehicles (EVs).Guest Blog | October 7, 2020
Environmental analysis is complicated because the world is complicated. Obnoxious wags may say, “don’t assume, you make an ass out of u and me,” but usable analysis of any complex subject requires dozens of simplifying assumptions. Honest analysts like the Union of Concerned Scientists (see my previous blog post) are transparent about how and why they made their choices. And, when they make a mistake, they issue a correction.
Dishonest shills, on the other hand, use complexity as camouflage, hiding their lies in the numbers, equations, assumptions, and missing information. They’re counting on the fact that most people won’t ever read the report closely enough to catch them, and that only a small fraction of those who do will be able to spot the subterfuge. And when they do get caught, they don’t correct; they counterattack.
One common FUD (Fear, Uncertainty, and Doubt) claim is that manufacturing EVs embodies so much more energy (or other environmental damage) than internal combustion vehicles (ICVs) that the deficit can never be overcome during operation. Rather than do a full-blown, in-depth, complex analysis of this claim, let’s seek clarity by intentionally oversimplifying.
“Scratch and Sniff,” The Basic Smell Test
Let’s compare a Tesla Model 3 to its natural competitor, a BMW 330i, using data from Motor Trend. The Tesla weighs 4,062 lb (1,846 kg), and consumes 290 watt-hours of energy per mile (Wh/mi) on the EPA combined cycle. The BMW weighs 3,646 lb (1,657 kg) and gets 30 mpg on the same cycle.
Unleaded gas contains 33.7 kilowatt-hours of energy per gallon (kWh/gal), and Americans drive about 1,000 miles per month. During my career, it was a widely-used rule of thumb that cars embodied 100 mega-joules (MJ) per kilogram, or 27.8 kWh/kg. This reference puts the number at 90 MJ/kg, but let’s use the larger, more conservative value. Note that we’re not separating the steel, glass, plastic, and other recyclables. We’re saying that every kg is a kg of “car.”
Running the numbers, we see that the Tesla embodies 51,320 kWh, and consumes 3,480 kWh per year of operation. The BMW embodies 46,070 kWh, and consumes 13,480 kWh/yr. But the differences between the two are what really matter.
Vive La Difference!
Manufacturing the Tesla requires 5,250 kWh more than the BMW, once. Operating the BMW requires 10,000 kWh more than the Tesla, every year they’re on the road. The BMW gets a head start, but the Tesla makes up the difference in 6,300 miles, less than seven months with average driving. EV battery warranties last 8 years / 100,000 miles. Does anyone seriously believe that accounting for material variations, or analyzing a rear-wheel-drive Tesla with the standard battery (as opposed to the heavier, less efficient dual motor, long-range version Motor Trend tested), or otherwise complicating this analysis would tip the result in the ICV’s favor?
The Automotive Food Chain
Unfortunately, FUD artists aren’t the only ones making bogus arguments about embodied energy. Lots of environmentalists do, too. Most of us are conservative, in the sense of frugal, not wasteful. This leads some of us to argue that the environment is best served by keeping a gas-powered vehicle (for example, a Prius) until the wheels fall off, on the premise that doing otherwise would waste the energy embodied in the car. Dead wrong.
Except in costly, ill-advised “cash for clunkers” programs, we don’t just throw cars away when we’re done with them. They’re part of a well-established food chain.
New cars are luxury items. That new car smell is the most expensive perfume in the world, and just as ephemeral. New car buyers, even those buying the least expensive economy models, are people rich enough to ignore utilitarian definitions of value and indulge in that luxury.
Utilitarian buyers let others eat the rapid depreciation. They buy used cars and drive them until the maintenance hassle outweighs the dollar cost of replacement. Then they sell to someone, usually not as well-off, who’s comfortable with a higher ratio of hassle per dollar. There may be several more of these transactions before the car can’t be kept running any longer. Even then, it isn’t thrown away. It gets parted out, an organ donor keeping its siblings alive as they near the end of the food chain.
Consumerism Isn’t All Bad
When we (conservative, frugal folks that we are) argue that keeping a car until the wheels fall off is the most financially sound course of action, it’s hard to disagree. But we need to stop there. If we go on to preach that it’s the environmentally sound course, we’re guilty of baseless self-flattery.
By definition, only rich people buy new cars. But new cars are the only kind of cars that auto manufacturers manufacture. Which means that rich people don’t just decide what rich people drive; they decide what every driver drives. Counterintuitive though it may seem, the most environmentally sound strategy would be for rich people to buy or lease the newest, cleanest, greenest machines available, then quickly trade them in on newer, cleaner, greener machines. Wash, rinse, repeat. Fill the food chain with EVs, instead of Escalades and Expeditions.
Note about this blog series author, Dave Erb: In a four-decade automotive engineering career focused on energy and emissions, Dave developed vehicles using gasoline, diesel, biodiesel, alcohol, natural gas, electric, and hybrid-electric powertrains. From 1995 to 2004, he created and taught a three-day professional development short course on “Design of Hybrid Electric Vehicles” for the Society of Automotive Engineers. He is the author of Chapter 1 of “Driving to Net 0: Stories of Hope for a Carbon-Free Future,” a collection of 15 first-person accounts of families pursuing sustainability by combining solar houses with electric vehicles, and a volunteer with the Southern Alliance for Clean Energy.