The context
Source: Calculated from Federal Reserve of St. Louis (FRED) data, series GASREGW (week, regular gasoline) and CPIAUCSL (CPI), accessed 6/26/2022. This is the average U.S. price for a gallon of regular, in constant May 2022 dollars.
The price of gas appears to be peaking, at least for the short term. Per the AAA, the price has fallen in the past week, in tandem with a drop in the price of oil. Looks like the peak this time likely will be just under $5.02 per gallon of regular, as measured by the AAA on 6/14/2022.
I figured I should mention that. That’s good news for most people, and can’t be used for hate-the-President propaganda. Ergo, you’re not likely to see that given much press coverage.
Just two other bits of context, before I get to the actual post.
First, as I noted a month ago (Post #1512, May 15, 2022), that’s not even close to a record price of gasoline in the U.S., in real (inflation-adjusted terms). Despite all the press coverage. In constant May 2022 dollars, gas was materially more expensive in July 2008.
Second, in July 2008, there was a Republican in the White House. Who, at that time, had just about as little control over the price of gasoline as the current President does, now.
Part 1: Electrical transport in a Prius Prime
Source: FHWA NHTS BRIEF: Electric Vehicle Feasibility, Can EVs take US Households to where they need to go? U.S. Federal Highway Administration, July 2016
In a nutshell: Giving your car thirty miles’ worth of battery power can electrify a surprisingly high fraction of all your vehicle miles.
My wife bought a Prius Prime last year, and the electric vehicle (EV) capability of that car continues to amaze us.
The Prius Prime is a PHEV (plug-in hybrid electric vehicle). It has enough battery for a bit over 30 miles of all-electric travel, after which it seamlessly transitions to being a standard gas hybrid. Full recharge takes about five hours, plugged into a regular 120 volt household outlet, or about half that time at a level-two (240 volt) charging station.
It’s a hassle-free step toward having an EV (electric vehicle).
And that turns out to be a relatively cheap and hassle-free way to reduce your carbon footprint. Because, unless you live in a state with extremely dirty electricity, switching from standard gas car to an EV will put a serious dent in your carbon emissions.
Source: This ScienceDirect article.
The emissions difference shown above is close to what I’ve measured for my wife’s Prius Prime. Battery-powered miles in a Prius generate about 60% less C02 than gas miles in a Prius. That’s based Virginia’s mix of electrical generation sources, but Virginia’s mix is quite close to the U.S. average.
I think most people capable of telling fact from fiction understand that. Electrical transport is carbon-sparing relative to transport directly powered by combustion of fossil fuels.
But that graph above is for a full-fledged EV. The emissions savings shown above is literally for a Tesla. How much good can you possibly do with a dinky little 30-mile battery?
Answer: Quite a lot. In our case, adding that modest 8 kilowatt-hour (KWH) battery to a standard Prius has allowed us to electrify roughly 75 percent of our total vehicle-miles.
The reason for that is simple: Most car trips are short. Most of the driving that most people do is around-town driving. E.g., the average one-way car commute to work in the U.S. is 12 miles. As a result, on most days, most vehicles travel less than 30 miles. And sure, one can put a lot of miles on with (say) a long vacation trip. But that doesn’t offset the fact that 30 miles covers a huge chunk of the average driver’s daily driving.
But what about the average U.S. driver? Turns out, you can use a Federal survey (the National Household Travel Survey) to calculate that. When I download that survey, total up daily miles by household and vehicle, then swap out the first 30 miles a day for electricity, I find that universal use of a 30-mile-battery PHEV would electrify 43% of all U.S. personal vehicle miles driven in the U.S. That’s allowing just one charge per day.
So our vehicle use is not quite the same as that of the average U.S. driver. But enough people take enough short trips that even a 30-mile battery range would electrify a huge fraction of all U.S. driving.
After the Federal tax rebate of just over $4000, the net price of the Prius Prime was no different from that of a standard Prius. Basically, it’s a standard Prius, with the EV capability thrown in for free. We (my wife) effectively bought us 3/4ths of an EV, for nothing.*
* My wife clearly inherited her mother’s shrewdness genes. She traveled to Connecticut to get a deal, paid under $27K all-in. With the tax rebate, the net cost was just under $23K. That was just before all this car-shortage stuff began to hit.
There are a couple of downsides to the PHEV version of the Prius.
One is that the luggage space is smaller. That’s where they put the 8 KWH battery. The hatchback space falls from 27 cubic feet for a standard Prius, to 20 cubic feet for the Prius Prime. So there really isn’t room in the hatchback for more than a few small suitcases.
The second may or may not be battery life. In theory, that 8 KWH lithium battery is good for the life of the car. In practice, PHEV use just beats the crap out of a battery, relative to EV use. That small battery has to be capable of powering the car, so the ratio of peak discharge rate to total battery capacity is higher. But what really wears the battery out is the total number of complete charge/discharge cycles. And there, using that smaller battery more intensively leads to a greater number of total charge/discharge cycles per unit of time. Typically, we fully discharge that battery every couple of days or so. For a typical modern EV, with a 300-mile range, you might go through a full charge/discharge cycle every week. Per unit of time, PHEV use puts three or four times as much wear on the battery as EV use would.
On the plus side, that battery has a 10-year/150K mile warranty. And, because the battery is small and lithium (far cheaper than the original Prius nickel-metal-hydride, per KWH), if it fails, replacing it out of warranty shouldn’t require taking out a second mortgage. What the actual replacement cost would be in 2031 or later is impossible to predict.
Part 2: Gas transport in a Prius Prime
We bought a PHEV for the hassle-free electrical propulsion. But performance of the Prius Prime as a standard gasoline-powered hybrid continues to surprise us.
We’ve been consistently getting low-60’s MPG on long trips. That’s far better than the EPA rating of 53 MPG on the highway.
And now, this week’s trick: 72 MPG on the highway, for roughly 100 miles of non-electric travel on Maryland’s Eastern Shore.
Admittedly, conditions were ideal: Flat, mostly open road, moderate (60 MPH typical) speeds. Summertime gasoline, which has slightly higher energy content than winter-blend gas due to the oxidizers added in the winter. Plus, the usual going-to-the-beach traffic jams which (no sarcasm) do wonders for your gas mileage if you’re driving a Prius.
But I wasn’t doing anything special. I just try to keep the car in the “eco” range on the dash display, to the extent that’s practical. But I’m a feather-footed driver by habit.
Oh, and I wasn’t driving like this. This, being part of the drive cycle that the EPA uses to estimate gas mileage for U.S. vehicles:
Source: US EPA.
But this does make me question whether the current more-stringent EPA test methodology handicaps an Atkinson-powered hybrid like the Prius. The EPA changed its methods a while back to give a closer simulation of “real-world” conditions. This includes several segments of driving like a bat out of hell, as shown above. And while the Atkinson-cycle engine of the Prius is efficient, it’s not very good at producing a lot of power. When you want power, you have to push that engine far out of its most efficient range of operation. So I wonder if the mileage hit on the Prius is much larger than on a car with a standard (Otto-cycle) engine.
In any case, for whatever reason, we get far better gas mileage than the EPA estimate. This last trip was just even more of that.
Conclusion: Why I don’t give a 💩 about the price of gas.
I guess it should be obvious by now that I don’t have a lot of sympathy for folks who choose to drive big, gas-guzzling cars, then complain about the current price of gasoline. I figure if you can spend $80K on a GMC Yukon, you can just suck it up for the additional $1700 a year you’ll have to pay if the price of gas goes up a couple of bucks.
But mostly, I don’t care personally for the simple reason that I don’t use much of it. My wife had the foresight to get a PHEV. Given out travel patterns, three-quarters of our miles are now electric. The other quarter is mostly for long trips, where this car is taking the “gas-sipper” reputation of the Prius to new extremes.
And those capabilities didn’t cost us anything. On a lifetime-cost-of-ownership basis, barring catastrophe, this is going to work out to be just about the cheapest new car we’ve ever owned.
What can I say? Gas prices will go up and down. Consider planning accordingly.
