120MPGe is it really?…

[ItsNotAboutTheMoney]

MPG was a problematic unit even when applied to liquid fuel burners. L/100km is a much more sensible unit for quite a few reasons.

MPGe is even more nonsense, especially because the grid is dramatically different in different parts of the country. But the figure helps people to compare apples to orangutans when car shopping.

A better comparison is MPG vs mi/kWh, because that ratio x electricity price in cents = equivalent liquid fuel cost in gallons. 20 mpg / 2mi/kWh = 10 x $0.14/kWh means I would pay the equivalent of $1.40/gallon to fuel an F150 Lightning at home, for example.

Fun little factoid: an EV charged on solar power produces less gCO2e per mile than the fossil fuel industry wastes bringing the fuel to market.

MPGe is good for showing the relative efficiency of the _vehicles_ based on the units that Americans are used to.
It's not about cost.

MPG does not take into account well-to-tank energy use.
MPGe does not take into account well-to-wall energy use.

To have different units, the USA would need to change from MPG for gasoline vehicles.

 

[David99]

From an economic perspective $/mi is the only thing that matters.

I would not drive an ICE vehicle even if someone would give me gas for free for life.

 

[ItsNotAboutTheMoney]

From an economic perspective $/mi is the only thing that matters. That is a great metric for comparing ICE to EVs. When Supercharging during peak hours ICE can actually match an EV in some cases for $/mi.

When charging at home or work is where EVs really shine for $/mi.

However, fuel economy ratings are measured from testing defined by the _Environmental Protection_ Agency not the Department of Commerce.

 

[mpgxsvcd]

That is the best way to explain why e-fuels are not a good alternative let alone an alternative. Burning something to create motion just isn't an efficient method, no matter how or what.

Even fuel cells are terribly inefficient. Water is inherently inert with respect to potential energy.

In order to extract Hydrogen from water you have to put an extraordinary amount of energy into the water and the energy you get back is greatly diminished.

Just put the electricity straight into a battery. That is the only thing that makes sense at all.

 

[mpgxsvcd]

However, fuel economy ratings are measured from testing defined by the _Environmental Protection_ Agency not the Department of Commerce.

And the EPA numbers are basically unrealistic and useless. $/mi is extremely accurate and completely relevant to almost everyone.

 

[Zythryn]

And the EPA numbers are basically unrealistic and useless. $/mi is extremely accurate and completely relevant to almost everyone.

Not when you are comparing efficiency.
As long as you use the same measuring stick, it doesn't matter how far the measurement from your personal experiences are.
An EV is twice as efficient as a hybrid which is twice as efficient as a run of the mill ICE (made up numbers).

It is the relative efficiencies that MPGe is meant to measure, not comparisons based on dollars.

Dollar cost can vary widely from state to state, city to city, even person to person within the same household.
If a car gets 100 MPGe, you know the efficiency is double that of a car that gets 50 MPG. It doesn't tell you what the price is.
Likewise MPG doesn't give you the price of fueling up. If you know the cost of gas, you can get a general cost. Similarly, if you know the cost of a kWh, you can get an estimated cost of charging an EV (using the posted kWh/100 miles).

In both cases, you need to take into account how close you normally get to the EPA numbers, but the info is there.

 

[Aaron Sanford]

Is MPGe a gimmick? Is the model 3 really getting 100+ MPG?

I’m finding it hard to believe my rough estimates show it more like 30-50MPG

I guess the argument is the cost of electricity say at super chargers.

But it seems like I’m charging driving 70-80 miles and it’s time to charge again even letting SOC drop to like 6%.

When I’ve had real fuel efficient vehicles would need to fill up like once a month…

Thanks

I drove 90 miles yesterday at an energy cost of $3.12 (NEMA 14-50 plug at home), which is less than one gallon of premium for our BMW340i. I’d say I’d get 100 miles for the price of one gallon of premium, not sure about these math geeks on here but that is 100MPGe to me!

 

[dbeiler]

I would not drive an ICE vehicle even if someone would give me gas for free for life.

Really? I actually enjoy Taco Bell regardless of the consequences. I'd happily drive an ICE for a lifetime of free Taco Bell.

 

[455dan]

Not when you are comparing efficiency.
As long as you use the same measuring stick, it doesn't matter how far the measurement from your personal experiences are.
An EV is twice as efficient as a hybrid which is twice as efficient as a run of the mill ICE (made up numbers).

It is the relative efficiencies that MPGe is meant to measure, not comparisons based on dollars.

Dollar cost can vary widely from state to state, city to city, even person to person within the same household.
If a car gets 100 MPGe, you know the efficiency is double that of a car that gets 50 MPG. It doesn't tell you what the price is.
Likewise MPG doesn't give you the price of fueling up. If you know the cost of gas, you can get a general cost. Similarly, if you know the cost of a kWh, you can get an estimated cost of charging an EV (using the posted kWh/100 miles).

In both cases, you need to take into account how close you normally get to the EPA numbers, but the info is there.

JMO but to be fair to ICE vehicles there should also be a cold weather MPGe test/rating.

Say -20F Vehicle required to maintain 70* interior temp.

I absolutely like my MYP but actually think that ICE vehicles do get cheated in the winter concerning the EPA EV MPGe ratings.

 

[ewoodrick]

Is MPGe a gimmick? Is the model 3 really getting 100+ MPG?

I’m finding it hard to believe my rough estimates show it more like 30-50MPG

I guess the argument is the cost of electricity say at super chargers.

But it seems like I’m charging driving 70-80 miles and it’s time to charge again even letting SOC drop to like 6%.

When I’ve had real fuel efficient vehicles would need to fill up like once a month…

Thanks

As other have said, MPGe is just a converted number.

It all comes back to the EPA numbers. The EPA numbers are intended to allow a buyer (and the government) to compare model to model, manufacturer to manufacturer and year to year.
People try to read much more into those numbers. When you consider that they were created back during Nixon's 55 mph maximum speed, they start to make a little more sense.

Supercharging will be very cost comparative to ICE fuel costs.

Charging at home is where EVs shine. In many parts of the country, home charging is 25% of Supercharger charging.
And when charging at home and plugging in, I NEVER have to stop and refill unless taking a trip. Which is over 90% of the miles in the US.

While on Interstates, you should be able to easily go 100-150 miles without stopping.

 

[Zythryn]

JMO but to be fair to ICE vehicles there should also be a cold weather MPGe test/rating.

Say -20F Vehicle required to maintain 70* interior temp.

I absolutely like my MYP but actually think that ICE vehicles do get cheated in the winter concerning the EPA EV MPGe ratings.

I agree that information is useful, as long as the efficiency loss of both ICE and BEVs are shown.
I very much liked the range estimate page Tesla used to have which allowed you to change wheel size, temperature, etc.

 

[David99]

I agree that information is useful, as long as the efficiency loss of both ICE and BEVs are shown.
I very much liked the range estimate page Tesla used to have which allowed you to change wheel size, temperature, etc.

between 15 and 25% rage loss on ICE vehicles in very cold temperatures

Fuel Economy in Cold Weather

Cold weather and winter driving conditions can significantly reduce fuel economy.

www.energy.gov

 

[Zythryn]

between 15 and 25% rage loss on ICE vehicles in very cold temperatures

Fuel Economy in Cold Weather

Cold weather and winter driving conditions can significantly reduce fuel economy.

www.energy.gov

Yep, over a typical winter my Prius would loose ~20% efficiency, my former Model 3 about 30%.