...using a common unit of energy measure--if my goal were to simply compare the energy usage of electric versus ICE. The calculations, if you get into the weeds of it, are highly complex, as there are so many physical components and activities involved in getting the energy in gasoline or stored electricity converted to mechanical energy to make your car travel.

My own approach is simpler: what is my cost per mile for energy? I have a non-plugin hybrid, so all energy inputs from outside the system are in the form of gasoline. Gas at our local station is about $3.10 right now, and I get about 50 mpg overall. This means that my cost of energy per mile is about $0.06. Back when I had an all-ICE car, was getting 30 mpg, and gas was $3.50, I recall calculating my cost at about $0.12 per mile.

All-electric vehicles seem to be paying a ranger of unit costs for power; it depends on whether you use a home charger, a commercial fast charger, whether you charge at night or during the day. etc. Apparently about 90% of EVs are charged at home overnight. I've seen quotes of $0.16 per KWH as a national average, but that will vary materially across the country. anyway, if you figure an EV will typically get abut 3 miles per KWH; at $0.16 per KWH, that's a cost of $0.05 per mile. This is far superior to the cost of about $0.12 per mile that I estimated for all-ICE cars but pretty close to the $0.06 per mile I calculated for my non-plugin hybrid (a 2021 Camry).


Here's a short paper with an interesting graph comparing EVs, HEVs, and ICEs as to price per mil: Comparing Energy Costs per Mile for Electric and Gasoline-Fueled Vehicles (Idaho National Laboratory, document created in 2014, so a bit dated.)

Here's a more current web article on EV energy costs: How Much Does It Cost To Charge an Electric Car? (Nick Kurczewski, kbb.com [Kelley Blue Book website], 12/13/2023.)

Give or take, depending on blend.

But most ICE’s lose about 2/3 of that energy to heat, with only 1/3 going to the drive train or other car functions .

Ev’s deliver 80-90%+ to those functions.

At least in California, where we have amongst the highest kWh cost, my energy costs are about 1/3 of an ICE vehicle for my EV.

But 6.67 may be overstating the case?

The fuel-content factor of 6.67 for electric vehicles (EVs) is a part of the methodology used in the United States by the Environmental Protection Agency (EPA) to compare the energy efficiency of electric vehicles with that of gasoline-powered vehicles. This factor is used in the calculation of miles per gallon equivalent (MPGe), which is a measure that allows consumers to compare the energy efficiency of electric cars with traditional gas-powered cars on a familiar basis.

Here's a simplified explanation:

1. **Basic Concept**: The idea is to equate the energy content of gasoline to the electrical energy used by an electric vehicle. In the U.S., the energy content of gasoline is generally considered to be about 33.7 kilowatt-hours (kWh) per gallon.

2. **Fuel-Content Factor of 6.67**: This factor is essentially a conversion number. It means that 1 kWh of electricity is considered equivalent to 1/6.67 gallons of gasoline in terms of energy content. This is derived from the energy content of gasoline. Since 33.7 kWh is the energy equivalent of one gallon of gasoline, dividing this number (33.7 kWh/gallon) by 1 kWh gives you approximately 6.67.

3. **MPGe Calculation**: To calculate an EV's MPGe, the EPA divides the distance an EV can travel on a fully charged battery (in miles) by the energy content of the electricity (in kWh) used to charge the battery, and then multiplies this number by the fuel-content factor of 6.67. This provides a miles per gallon equivalent that can be compared to gasoline vehicles.

4. **Purpose**: The MPGe metric helps consumers understand how an electric vehicle's efficiency compares to a gasoline vehicle. Since most people are familiar with miles per gallon (MPG) for gasoline cars, MPGe provides a similar reference point for electric cars.

5. **Limitations**: This approach has some limitations. It doesn't account for variations in the source of electricity (like coal, natural gas, renewables, etc.), which can have different environmental impacts. Also, it doesn't consider the energy used in producing and transporting gasoline versus electricity.

In summary, the fuel-content factor of 6.67 is a part of a calculation method used to provide a common ground for comparing the energy efficiency of electric and gasoline vehicles, despite the inherent differences in how these vehicles use and store energy.

------ End ChatGPT --------

Bottom line is that that author of the WSJ Oped, misused the 6.67 multiplier and made up his own use for it. Not surprisingly, the WSJ published his bullshit anyway, without doing a simple check.

Fueleconomy.gov rates the 2022 Tesla Model Y at between 111 to 129 MPGe, depending on model. My BMW iX is rated at 86 MPGe, which is pretty spot-on based on my driving.

Sounds to me like Mr. Buschbacher's OpEd is full of bullshit.

at least mildly off or even way off. That still leaves the question to this layman about the high multiplier being used.

That's the point.

FuelEconomy.gov says a Tesla Model Y gets ~120 MPGe. If you divide that by the energy in a gallon of gasoline (33.7 kWh), that means the Tesla can go 3.56 miles on a kWh of electricity.

I don't own a Tesla, so I can't comment on actual driving experience, but Car and Driver's numbers (linked below) are in line with FuelEconomy.gov.

FuelEconomy.gov's numbers are accurate with my personal driving experience of my BMW iX, where I get 2.6 miles per kWh, or 33.7 kWh x 2.6 = 87.62 MPGe.

Nobody is using the 6.67 multiplier but the Oped author.

• Click here for link at https://www.caranddriver.com/tesla/model-y-2022

The ChatGPT explanation states that the MPGe calculation is made by taking range divided by battery capacity times the conversion factor:

From your post

3. **MPGe Calculation**: To calculate an EV's MPGe, the EPA divides the distance an EV can travel on a fully charged battery (in miles) by the energy content of the electricity (in kWh) used to charge the battery, and then multiplies this number by the fuel-content factor of 6.67. This provides a miles per gallon equivalent that can be compared to gasoline vehicles

I don't know if ChatGPT is correct, but it is explicit that MPGe is calculated with the 6.67 factor.

So is the multiplier irrelevant or not?

Of course, it's explanation of how the 6.67 comes about makes no sense mathematically, so it's explanation here could make no sense as well.

either. I think since I asked the question, it tried to make sense of it. And failed. My bad for using it in my retort.

After endless Google searches and ChatGPT queries, the 6.67 multiplier has no bearing on anything and seems to be spun out of whole cloth.

Bottom line is that nobody uses the Oped writer’s methodology in computing MPGe.

...then the cost of energy would be $10.333 per mile. In my post above in this thread I cam up with an estimate for an all-EV of a cost for energy inputs of about $0.05 per mile. So if you just did (10.333/5) X 35, you might say that the miles-per-gallon equivalent would be about 72--sort of in the ballpark for your beamer. If the cost for the EV were more like $0.04 per mile then the MPGe would be about 90.

I would think that the MPGe calculation is prone to the same wide variability as gasoline MPG is, based on, e.g., the vehicle model, age, and maintenance history; the driver's habits; the type of driving done, the climate, etc., etc. (which is why some years back I decided to mostly keep track of my energy cost per mile versus MPG).