Learning to do green math

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The announcement from the electric vehicle (EV) charging company contained a really big number: 1 million. That’s the number of places in North America and Europe where drivers can go to charge up their cars, according to ChargePoint, a California company that provides a list of those charging stations on its smartphone app. And it’s important because the lack of a robust charging network has been one of the main obstacles to the mass transition from fossil fuel to battery power.

But the number also made me wonder, How does that stack up against the number of service stations where drivers can pump gas or diesel? And since charging an electric car takes longer than filling a tank, does the EV industry need more plugs than pumps anyway?

The rough answers to those questions were easy to find—the American Petroleum Institute says there are more than 145,000 traditional fueling stations across the U.S., and Statista puts the number in Europe at around 135,719—but those numbers only raised more questions for me. For example, each filling station typically has between four and eight pumps, so shouldn’t we multiply the number of stations by the number of hoses at each one? As it turns out, ChargePoint’s number is the total amount of ports—or plugs—not the number of locations. So I was trying to compare apples to oranges.

Don’t get me wrong—providing drivers with a list of a million charging stations is an awesome achievement—but the number also demonstrates the difficulty of comparing electric and fossil fuel infrastructures.

Here’s an example: We recently learned about a $3 billion EV battery factory being planned as a joint venture by the automotive giants Cummins, Daimler, and Paccar. Intended to ensure a U.S.-based supply of commercial and industrial batteries, the plant will be a 21-gigawatt hour (GWh) factory. I’m not an engineer, just a humble reporter, so that number meant precisely nothing to me. And when I tried to figure out how that would stack up by more conventional measures of production capacity, I ran up against the vagaries of “green math.”

First, a little background: In transportation terms, gigawatts are like horsepower—a measure of maximum potential output—and so, gigawatt hours are like horsepower multiplied by endurance. But of course, no one drives their car at top horsepower all the time—they’d quickly collect a stack of speeding tickets at the very least. Maybe that’s why legacy automotive plants don’t measure their vehicles’ output in “horsepower hours.”

Further complicating matters, an EV battery is like an internal combustion engine (ICE) and its fuel tank, all wrapped up in one box. Describing the “power” of that box with a single number requires that drivers think about energy in a new way. Here’s the best I could do: That new battery factory would be able to offer a single charge-up to about 48,000 electric Freightliner eCascadia trucks. But that math only works in the absurd scenario where those truckers somehow all come in for a charge on the same day and claim the plant’s entire annual battery output.

It was a similar story when I started looking into the driving ranges of EVs versus their gas-powered counterparts. That seems like a simple concept, but I stumbled over that one too when I learned that my friend’s Ford F-150 Lightning electric pickup truck has an EPA-estimated range of 300 miles. Pretty impressive: That’s more than my Toyota Rav4, which runs about 240 miles on a tank of gas. But wait a minute, that’s not a fair comparison because maybe the Rav4 has a smaller gas tank, so … but hold on, the Lightning doesn’t even have a gas tank! See, I lost my direct comparison again.

Fortunately, the next generation may have this thing figured out. We now have two teenage drivers in the house, and whenever I hand my son the keys to that Toyota, he sets the digital dashboard display to show the car’s estimated remaining mileage. Call me old-fashioned, but all these years, I’ve just been keeping an eye on the analog gas tank needle to see when I needed to fill up. If you change your mode of thinking to watch the number of miles the car can go, not the number of gallons left in the tank, it no longer matters whether you’re burning gasoline or electrons under the hood. Wait a minute, an EV doesn’t actually burn any electrons … oops, I did it again.



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