A gallon of gasoline can generate ~33kWh of power
by Kali4niaND (2024-01-30 21:50:52)

In reply to: I feel like the story here is incomplete.  posted by ndroman21

Cannot Reply Return to Political

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.

So it seems some sort of efficiency factor is warranted?
by ndroman21  (2024-01-31 06:58:34)     cannot delete  |  Edit  |  Return to Board  |  Ignore Poster   |   Highlight Poster  |   Cannot reply

But 6.67 may be overstating the case?
ChatGTP explains the 6.67 fuel content factor...
by Kali4niaND  (2024-01-31 13:19:22)     cannot delete  |  Edit  |  Return to Board  |  Ignore Poster   |   Highlight Poster  |   Cannot reply

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.
That was my gut instinct. Thanks. *
by ndroman21  (2024-01-31 14:03:50)     cannot delete  |  Edit  |  Return to Board  |  Ignore Poster   |   Highlight Poster  |   Cannot reply

I'm not sure where G.K.'s 430 number came from.
by Kali4niaND  (2024-01-31 09:53:38)     cannot delete  |  Edit  |  Return to Board  |  Ignore Poster   |   Highlight Poster  |   Cannot reply

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.
Let's assume the 65 number from the article is indeed
by G.K.Chesterton  (2024-01-31 17:24:43)     cannot delete  |  Edit  |  Return to Board  |  Ignore Poster   |   Highlight Poster  |   Cannot reply

at least mildly off or even way off. That still leaves the question to this layman about the high multiplier being used.
The multiplier is irrelevant in determining MPGe.
by Kali4niaND  (2024-01-31 18:37:54)     cannot delete  |  Edit  |  Return to Board  |  Ignore Poster   |   Highlight Poster  |   Cannot reply

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.
Doesn't your post a ove say the exact opposite?
by dfw  (2024-01-31 22:07:00)     cannot delete  |  Edit  |  Return to Board  |  Ignore Poster   |   Highlight Poster  |   Cannot reply

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.
It seems that the 6.67 multiplier makes no sense to ChatGPT
by Kali4niaND  (2024-01-31 22:20:55)     cannot delete  |  Edit  |  Return to Board  |  Ignore Poster   |   Highlight Poster  |   Cannot reply

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.
If an ICE got 35 mpg with gas at $3.10/g...
by Kbyrnes  (2024-01-31 12:07:51)     cannot delete  |  Edit  |  Return to Board  |  Ignore Poster   |   Highlight Poster  |   Cannot reply

...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).