EVs have big batteries. I’m talkin’ big ol’ batteries, baby. None more so than the GMC Hummer EV. This hefty electrotruck has a battery pack that weighs 2,923 pounds. It boasts a total capacity of 246 kWh—more than two Tesla Model S’s put together. And yet it pales in comparison to what a 1989 Geo Metro is packing in its diminutive little gas tank.
Today’s EVs struggle with one thing—energy density. Even our best batteries can’t hope to compare to the energy packed into delicious hydrocarbons like diesel and gasoline. That means a Geo Metro is hauling around more chemical energy in its gas tank than a Hummer EV with a fully charged battery.
Put your metric pants on, because we’re looking at some basic science, and unlike Hank Hill, I refuse to use BTUs. We’re gonna see just how GMC’s massive off-roader measures up to ancient hatchback in a way that ultimately doesn’t matter in the slightest. Let’s go.
Let’s Talk Turkey
Real talk, gasoline is positively brimming with energy; that’s probably not surprising given that some cars can get you a ridiculous 50 miles with just a milk jug’s worth of the stuff. Gas contains around 46.4 megajoules of energy per kilogram; measured by volume instead of mass, gasoline comes in at 34.2 MJ/liter or around 130 MJ per gallon.
[Ed Note: If we convert that to kWh per gallon, we can end up with a range, though the EPA typically says a gallon has 33.7 kWh of energy (121.3 MJ).
To put that into context, one gallon of gasoline, which weighs about six pounds, has the same energy as a 2017/2018 BMW i3’s entire battery pack, which weighs about 560 pounds. (To fairly compare, you’d want to add the weight of the gas car’s tank/pump, too, but that’s maybe 50 pounds). -DT]
Clearly, batteries are not nearly as grand as gasoline when it comes to energy density. Ultium lithium-ion batteries measure in at around 1 MJ/kg. Volumetric energy density is not much better, at around 2.27 MJ/liter. Gasoline is thus around 40 times better than GM’s current battery technology in energy per unit weight, and 15 times better in volumetric density. That’s on a per-cell basis, by the way—not counting all the extra volume and weight taken up by the battery pack structure itself.
So let’s go ahead and calculate the energy in a Geo Metro fuel tank. The fuel tank of the Metro has a capacity of 10.6 gallons, or 40.1 liters. Multiply that by the energy density of gasoline, and we find out the Geo Metro is hauling around 1371.42 MJ of energy in its fuel tank (380 kWh!). Maybe a squirt more if there’s some fuel in the lines.
The Hummer EV comes up short by comparison. At its full capacity, the battery stores 888.48 MJ or 246.8 kWh of energy. That’s only 64% of the energy in the fuel tank of the Geo Metro! Oh, and you can’t use all of that. Only 212 kWh is “usable,” or roughly 763.2 MJ. In contrast, the Geo Metro will pretty much let you drain the tank.
As an aside, consider this. The battery pack in the GMC Hummer EV weighs 66% more than a whole Geo Metro, and by itself, it won’t get you anywhere.
You might think with all that energy on board, the Geo Metro would get much farther down the road. Let’s pencil it out—you metric haters can join back in here. It’s got 10.6 gallons of fuel on board, and it’s rated at 45 mpg highway. Multiply that out and you get a range of 477 miles.
GMC rates the latest Hummer EV for just 381 miles of range in comparison. The official EPA rating has the 2024 model still pegged at 314 miles at best.
Those figures aren’t so bad for the Hummer, though! It has just 55% of the usable energy on board. At 9,640 pounds, it also weighs over five times as much as the Geo Metro, and perhaps more importantly, its aerodynamic drag is way, way worse. And yet, it achieves somewhere between 65% and 80% of the range of the ancient hatch! It also has 1,000 horsepower — the Metro, just 55 ponies. You can thank the hugely substantial increase in efficiency of an EV powertrain over an ICE powertrain for that. You can see that it can go 54 miles on 33.7 kWh of energy (MPGe) whereas the Geo can only get 41 miles on 33.7 kWh (the energy in one gallon of gas).
What does all of this mean? Nothing, really. It’s just a fun comparison between the sheer amount of energy you get in a gallon of gasoline, versus the weedy amount stored in a lithium-ion battery. Feel free to take this tidbit as a line for your next dinner party. “Did you know the Hummer EV has less energy in its three-thousand pound battery than a Geo Metro has in its tiny 10-gallon gas tank?” you’ll say. And everyone will think “You interesting, handsome, and urbane bastard. Bless you.” Or something.
[Ed Note: I’d like to just that I had a chat with Peter Rawlinson, the CEO of EV company Lucid. I asked him: What do we do about big vehicles like pickup trucks and SUVs, especially ones that want to tow? How do we keep those cheap? His answer, believe it or not: internal combustion. Yes, the leader of an EV company says the answer is internal combustion, and why? Because he’s an engineer who runs the numbers. Gasoline’s energy efficiency is simply incredible, as Lewin just showed, and that’s key when your vehicle is so big it requires loads of energy just to get down the street, and especially to tow.
Also, I’d like to highlight a quote about the GM EV1. From my article on my never-before-seen engineering documents:
“I said, ‘Roger, just keep in mind what we have here. We’ve got about a gallon of gasoline worth of energy in those 870 pounds of batteries, and we effectively re- fuel it with a syringe‘” is an amazing quote from former president of energy and engine management, Don Runkle, referencing former GM CEO Roger Smith (via Automotive News)
Note that the EV1 only had up to 26.4 kWh of battery, so really it was less than a gallon. Anyway, many of you engineers probably knew all of this stuff, but hey, we like writing about the Geo Metro! -DT].
Image credits: GMC, Geo, EPA
If you find some way to convert the matter in the Geo’s tank into energy it contains 12 gigajoules of energy.
How far would it go?
And if you are burning hydrogen that energy density is multiplied by 4, which goes a long way to explaining why rockets use it.
But mostly I just cant get over that the Hummer’s battery pack weighs 3000 fucking pounds. That’s as much as my midsized hatchback.
Electric drivetrains may be thermodynamically more efficient than ICE drivetrains, but they’re not that much more efficient. Accelerating 1.5 tons of mass just in your energy source alone is absolutely brutal on the overall efficiency of the system.
We’re going about this all wrong- EVs should be as small and light as possible to maximize their efficiency advantages. Every big EV SUV is a frigging waste.
No, they are absolutely that much more efficient. Gas drivetrains are typically in the ballpark of 30% efficient, while electric drivetrains are normally in the low 90s. That’s ~3x more efficient for those of you following along.
And that’s why, as wasteful and moronically engineered as the Hummer EV is, it uses considerably less energy to get down the road than most cars on the road, and WAY less than anything even close to that size. Hence the 53mpge.
I think you misunderstand, I am perfectly aware of how much more efficient an electric motor is compared to an ICE. But even being 3x better is still not good enough to justify dragging around a 9000lb+ monstrosity and the corresponding raw energy demands of that effort (as a delivery truck? sure, but that would require several times the useful payload the Hummer has).
Some people think the Hummer EV is okay, and we should accept it as just another one of those quirky EVs that pops up from time to time. I am not one of those people, and think we should burn it with fire before it reproduces. It is offensively bad engineering that has made humanity worse off for it’s mere existence.
I vote CP on the Hummer. Or is that not what we are here for?
I miss my metro; with a freeer exhaust, starting with a custom header, a cold air intake, advanced cam gear, and some minor weight reduction I had my non-xfi getting 54 mpg. And it was a blast to drive!
I consistently averaged around 52 mpg with my ’91 non-xfi Metro 5-speed. I replaced the factory spark plugs with Split-Fire™ plugs (remember them?) Otherwise, it was just the stock 3-cyl. (all 61 cu. in. of it.) Mine was fun to drive as well.
Ctrl-F “oxygen” – results : 0
Your missing by far the largest part of the equation. Gasoline, diesel, etc are worthless without oxygen. Remember AFR. For very gram of gas you’re burning, the ideally ICE needs 14.7 grams of air. So that ~60 pounds of gas in a Metro tank needs ~880 pounds of air (think about how much volume that is) to give up all those MJ, which as others have pointed out, mostly get thrown away, or get used to power a coolant system just to help throw them away.
Damn, so you’re saying the next mars rover can’t use the engine out of a geo metro?
We intentionally left that out because it doesn’t matter to the customer. The vehicle does not gain 880 pounds of curb weight.
I understand the reasoning, but for an article with such a scientific approach, it may be a disservice to skip the largest part of the equation, even if it’s only a single throw away line. This kind of deep dive can to some extent influence public opinion on BEVs in general.
I don’t see the practical basis for the inclusion of oxygen in the considerations of the article. It seems to me to be a comparison of the energy, and usable energy, you get from the gas tank compared to the batteries. The oxygen needed is free, and its functional acquisition cost already figured into the mpg ratings cited.
if you want to go into the entire chemical and thermodynamic picture, you’d have to expand the scope of the article to include heat. If you want to include the environmental impact, further broaden to encompass well-to-wheel considerations. To discuss ethical considerations…hoo boy, write a full book. I think this is a pretty well done, narrowly scoped article on the interesting topic of how much usable energy are you carrying in these two vehicles, and I allow the oxygen a free ride, since it’s not riding.
That’s the advantage of gasoline: It is fueled mostly by the air around you, so it doesn’t have to carry 880lb of oxidiser around. That’s why the Geo Metro wins in energy density, and why this article is relevant in the slightest.
In fairness, you can’t really use all the gas in the Metro’s tank either. At least, not for motion. A good 70% just gets wasted out of the tailpipe and radiator.
I love that kind of goofy engineering!
Now talk about the comparative efficiency in converting that energy to motion…
It’s about 30% ICE vs 99% EV. It basically got covered in the range estimate though.
So my Bolt with a 66kWh battery goes 270 miles in the city on the equivalent of 2 gallons of gas? Sweet!
As an EV conversion, with a series-wound DC motor and lead acid batteries, a converted Geo Metro retaining its manual transmission approaching GVWR consumes about 0.25 kWh/mile. This is 1980s tech that at the time was readily available to the hobbyist market.
With less weight from a battery upgrade to a modern chemistry and switching out the 1980s motor/controller for a modern drive system, given efficiency increases from these upgrades, this could easily go down to 0.20 kWh/mile and some converted examples with a modern Netgain HyperDrive system are even a bit less.
The Metro’s drag isn’t very good. It’s not as bad as virtually any SUV or truck even to this day, but it is still more slippery than most modern cars from the metric of CdA. This drag could be cut by about half with proper body design that favors efficiency over some arbitrary aesthetic(and the Metro’s sex appeal is already about zero, anyway). Keeping the same frontal area, a drag coefficient around 0.16 is very doable. See Dave Cloud’s “Dolphin” as a real world example of an Eco-Modded Geo Metro(it was designed to get 200 miles range using a ton of lead acid batteries). Doing so would cut that consumption down to about 0.14 kWh/mile.
Then upgrade the tires to a low rolling resistance variety and remove the transmission, going direct drive to a single axle ratio. Down to 0.12 kWh/mile.
Now, put a 33.7 kWh pack in this car. You’ve now got a reliable 250+ mile range at 70 mph in an EV, using the energy stored in one gallon of gasoline. This is for a battery about 1/8th of the mass, capacity, and most importantly, CO$T of what is in the Hummer EV. This car will have comparable weight to the ICE Geo Metro to boot, and you could add as many ponies as you like for hooning without compromising efficiency to any meaningful degree.
In this context, isn’t the Hummer EV the wrong way to go about this EV transition, especially if the goal is to get as many cash-strapped Americans as possible into EVs? The Hummer isn’t exactly affordable, after all…
This is trickle down economics. You must cater to the rich first, then eventually cater to the poor. Can’t let the poors have the cool shit first.
Unless you open the floodgates to Chinese imports, anyway. I don’t think the domestics are capable of building electric economy cars in domestic factories. They can’t even make traditional ICE economy cars here anymore
I was just ranting about this to my brother. It’s really really pathetic. Idk if I can bring myself to buy a car from the big 3.
Tesla already brought us over that hump (credit where credit is due), making EVs desirable and a symbol of wealth; the market is wildly different now from when GM planned the Hummer.
Now that we know, they should have done the Hummer first and brought out the Bolt EV now.
This is the issue. It’s really a matter of perception, and they created this perception, and it’s false. This is perhaps the biggest hurdle for EV’s. The perception that they are for the wealthy. Poor people own homes too. Tesla required a very high ROI, and bet on the long term. Throughout this term, they built the perception that EV’s were a symbol of wealth, to get that return. This has basically fucked us today if we really wanted a $25k car. I’m so incredibly frustrated that BYD is a vertical supply chain under communists rule, because that is the path to cheap. I am not fan of vertical supply chains much, either. I digress.
I dunno, I think in our marketplace, making EVs aspirational was the best way to make people want EV’s period, which now translates into demand for lower cost ones – the problem seems to be that all the manufacturers are busy replicating Tesla’s playbook, instead of taking the obvious opportunity of making lower priced ones.
Fully agree. First good $20-25k EV wins.
“and the Metro’s sex appeal is already about zero, anyway”
Its higher than the Hummer’s though.
I’m neither a science nor a math guy, but I would have found this interesting if you’d added a Diesel Rabbit to the mix, for comparison’s sake.
Very doable. Diesel actually is more energy than gas. The diesel Rabbit might also be more efficient.
That said, the Geo Metro is kind of /the/ headline tiny fuel sipper so it got the nod here.
I think diesel is 8/7 as energy dense, so 56 big macs in 1 gallon assuming my last comment of 49 per gallon was right, and my current assumption is right too.
This sounds like a good investigative reporting idea for torch to take on… Comparing various vehicles and animals on how far can they get off of the energy in one snickers bar.
Personally I prefer to convert everything to calories… A gallon of gas has the same calories as 49 big macs and the metro burns 1.2 big macs per mile.
Great stat.
THE best stat!!
Well I burn approximately 0.2 Big Mac per mile, so who’s the eco big shot now, Metro?
Call us when you weigh as much as a Metro.
Well, he’s not going to get there if he keeps walking off those Big Macs
A dude on a modern road bike doesn’t even use that many Big Macs to go a mile. Given the person is sending it, and doing around 300 watts at a fairly normal weight, so around 4 w/kg. You only need 1/15th of Big Mac to go that mile. Take that Geo Metro!
I just ticked over mile 3,000 on a BMC Roadmachine. My Garmin tells me I’ve burned 91,566 calories in that distance, which is about 2.6 gallons worth of diesel. So I’ve averaged the equivalent of about 1,154 miles per gallon of diesel in a little over a year! Granted, the bicycle and I weigh only about 150 lbs all told, including water and snacks.
While your hydrocarbon to carbon monoxide vs carbon dioxide conversion ratio seems to have been nearly perfect, more testing needs to be done on your particulate matter and noxious gas emissions.
Welp, I feel like the Hummer in this comparison. Fit me is 200, current me is… More. Maybe if I take these batteries out I can get a little closer…
For real though things haven’t been the same for me since my Felt AR4 was stolen. I’ve never been as comfortable on a bike and I haven’t had the money to replace it like for like. Telling the police I found it on Facebook and having them tell me “he said he bought it from a friend who bought it at a storage auction so it’s your word against his [i.e., we’re not going to do anything about it even though you literally solved it for us]” left me worried about securing another valuable bike without better storage on the property.
No receipts? Serial numbers?
I had a rough picture of the serial and the only receipt I had was text messages from the coworker I bought it from.
I gave an extremely detailed description of the bike, including wear on the bottom bracket from a dropped chain, a light bracket that fit my headlight, pedal clips that fit my shoes, and more. Things that weren’t shown in the pictures, and things that were shown besides (that light clip fits my light, etc), a description of the set installed, the fact that I had a black Felt AR4 58cm stolen from my house two days before the listing went up, the fact they’d cleaned my sweat off, the number of tick marks hidden by the stem. They didn’t care or look into it at all.
One bite
Use whatever unit you want, just not METRIC!
So, its a no on Royale With Cheese per mile?
Go with Crown Royal if you must do royalty.
I prefer F over C or K for temperature, feet and miles over meters and kilometers, pounds vs kilograms are kind of a wash for me, but for any distance under 4″ my brain automatically switches over to mm rather than trying to deal with centering 1 and 13/64ths.
I can think in meters/liters/kg but damn I cannot think in Celcius.
As a Brit I’m used to bouncing between imperial and metric, sometimes using both for the same object, but if I have to do any maths at all, then I convert everything to SI and go from there.
Americans: love French fries, hate French units.
The new CAFE requirement will be less than a mcdouble per mile 😛
Taco Bell is the better caloric since you’re comparing to gas….
Or White Castle.