MPGe Explained – Video

FEB 7 2015 BY ELECTRICCARSTV 46

Like it or not, MPGe is a plug-in electric car metric we’ll have to live with, at least for now.

In this MPGe primer video, CNET’s “Brian Cooley drills down on the new metric for rating MPG in cars like the BMW i8, Nissan Leaf and Chevy Volt.”

It’s actually rather easy to understand MPGe, but is this a useful metric for plug-in electric car buyers?  Considering that the EPA won’t clutter its window sticker with tons of rating, should MPGe be replaced with something more useful?

MPGe Explained

MPGe Explained

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46 Comments on "MPGe Explained – Video"

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Djoni

I would love to educate people to a more efficiency reality check.
Something like miles/KWh or kilometers/kWh.
Just put basic physic in play, people might not catch everything now, but they’ll get it.
MPGe is a bit tricky when no gas is burn.

Miggy

Agree get rid of this MPGe and use what the rest of the world use, km/kWh or kWh/100km
KISS.

Speculawyer

Can’t you see the value of the MPGe figure? Now every time someone does a news article on the most efficient cars, the electric cars all show up on the top of the list. This is GREAT for helping educate people on the much greater efficiency of electric motors (which they generally just don’t know).

Nix
The EPA intensively study-group tested multiple proposed versions of the new window stickers prior to their release. The study groups overwhelmingly found that study group participants in every major car market across the US universally did NOT want anything with kWh as a unit. In fact, the negativity in the study groups went even farther than that. When asked, they not only said they did not know what a kWh was, they overwhelmingly said that they did not want to learn what a kWh was. Let that sink in for a second. Now every EV fan I know has said they want EV’s to go mass market. Well, the mass market has their own demands too. And one thing they don’t want to compromise on is having to learn something new besides MPG numbers. Bowing to the masses and providing them with MPG-based numbers is part of the price of EV’s going mass market. As enthusiasts, we will collectively just have to accept that as part of the price we will be willing to pay for our EV’s to go mass market. Meanwhile, we enthusiasts can simply ignore the big MPGe number that is there for the mass market customers,… Read more »
ClarksonCote

Not a bad video, but I didn’t like his explanation for why traditional hybrids don’t have MPGe. He stated it was because the EPA felt those cars were “too conventional”

No, traditional hybrids don’t have MPGe because their only source of energy is gasoline. You can’t plug them in. So MPG is the only relevant metric.

Plug-in hybrids and all electric vehicles use electricity as a fuel source, and in those cases, MPGe is an attempt to equate their efficiency at using those fuel sources to the more typical “MPG” metric everyone is used to.

I liked the discussion on how MPG efficiency gains can be deceiving (i.e. an increase from 12mpg to 14mpg saves far more fuel than an increase from 40mpg to 42mpg)

Nix

I think using gas for 100% of their energy is exactly what he means by “too conventional”?

Djoni

And it would dramaticly show how inneficient are ICE!

What’s wrong with MPK ???
(miles per kWh) (kiloWatt-hour)

Anyone who’s ever looked at an electric utility bill knows what a kWh is.

Makes perfect sense (and cents) to me!

Leaf Errickson

I agree, M/KWH is a much more accurate metric of the cars efficiency. The fluctuation in gasoline and electricity rates makes MPGe rather nebulous.

Speculawyer

Nothing is wrong with it and they provide you the information needed for that value right on the sticker. Just flip the X KWH per 100 miles into 100/X miles per KWH.

Nix

What makes sense to enthusiasts is not what these window stickers are for. These are for non-enthusiasts, and when the EPA asked non-enthusiasts, they overwhelmingly said they wanted something based upon their familiar MPG number.

If we want EV’s to go mass market, there are some sacrifices we need to make for the sake of the mass market. That includes being 100% satisfied that they provide enthusiasts with the small number rated in “kW-hrs per 100 miles”, while the big number is in MPGe for the mass market.

mskz06

umm.. the label states kwh/100miles also. Cant calculate mpge without it.

There is nothing wrong with this system. It keeps the rating based on energy equivalent (33.7kWh=1 gallon of gas) . It allows people to see how efficient the EV is at using fuel. So at 10 cents per kWh, you are basically paying $3.37/gal for fuel. It also allows people to see how outrageous these charging network prices are at 20 cents, 30 +cents kWH, or $6.74-10.11+ per gallon at a time when fuel is under $3 gallon.. way to punish EV drivers for having more efficient cars. LOL.

Lustuccc

At 10¢ per kWh, the Leaf gives you 100 miles with 34 kWh.

How long do you go with 3.40$ of the black poison?

Three times less according to fueleconomy.gov

Why keep it simple when you can complicate it?!?

Miles per kWh IS simple.

pjwood1

Elroy, Your own mistake shows what’s wrong with our chemical “MPGe” statistic. 10 cent kwh don’t come close to equating to $3.37/gal, in terms of performance or economics. They beat it cold. It’s that simple.

Miles per kwh, like everyone else is saying. EPA has made a big mess of U.S. Monroney stickers.

I’m impressed that they did this exercise at all, it’s a milestone in EV awareness.

They should have hired ClarksonCote as a technical advisor though.

ClarksonCote, let me know if you’ve got a few spare cycles to sell, we’ll create another video and set the record straight.

EV

MPGe: dumbest most useless thing

Tesla 85kW: 265 Miles Per Charge, not 94 MPGe

simple s***

Speculawyer

No, it is not stupid. It serves the purpose of showing people that electric cars are much more efficient.

Nix

Efficiency and range are two completely different measurements. You could have a car that is rated at 500 MPGe, and only have a range of 5 miles. You can’t compare the two measurements at all, because the two don’t measure the same thing.

EV

why would i want to know the gas equivalent? i dont give a fuggg about gas!

So if your EV got 10mpge and used more energy, and had more environmental impact than a gas car, you wouldn’t want to know? (Assuming non-renewable power sources)

vdiv

Exactly, they are not equivalent. Why not use pounds of anthracite coal or ounces of U-235 to really discourage EV adoption while we’re at it?

Lustuccc

+1

lithium

Must admit, miles per oz of u235 would be an interesting metric.

Priusmaniac

Or cubic meter of Niagara falls water equivalent per mile or average roof photovoltaic hour per mile to encourage people

Nix

The problem is that the EPA tested each of their proposed new stickers on a wide number of study groups. They all unanimously and overwhelmingly thought that anything measured in kWh was as meaningless to them as “miles per oz of u235” or “cubic meter of Niagara falls water equivalent per mile”.

The point of the stickers is to provide information to these exact mass market consumers. The same consumers we keep saying we want to buy EV’s and PHEV’s. If we want them to buy them, we have to be willing to at least agree to talk to them in a language they are comfortable with and intuitively understand.

That is the value of MPGe.

Someone out there

Perhaps you don’t but many do. Showing how much more efficient an electric vehicle is is good in my book.

Brian Henderson

The Dept. of Energy created MPGe as a way to educate gasoline users on the cost savings associated with going electric. eg: Helps to educate that a 98 MPGe EV can travel 4-times further compared to the average 24.5 MPG gas-power vehicle on the same (equivalent amount) cost of energy.

note: actual costs differ as the volatility in gasoline pricing makes posting electric-to-gasoline price ratios difficult. The “Ge” (gallon-equivalent) comparison communicates at least 1/4 the cost per mile.

pjwood1

The volatility of gasoline pricing? Gasoline has less pricing volatility, than if you get in a car and check simultaneous electricity prices, on a drive straight across the country.

The ~$50,000 median U.S. income wants to know how far they can go on a dollar, not to play 6 degrees of separation with other energy forms.

Nix

pjwood — Actually, the EPA already extensively and exhaustively study-grouped US car buyers. They overwhelmingly and universally across the US said they preferred a unit that they already recognized and intuitively understood — without having to learn anything new.

MPGe was by far the most popular, even though it doesn’t translate directly into cost per mile.

By the way, study groups also out-right rejected Cost per Mile numbers on EPA stickers for gas cars too. They preferred miles per units of energy consumed, over cost per mile for gas cars too.

Brian Henderson

MPGe is great for comparison shopping, and educational discussions.

For charging (kWh) and driving (miles, km) …
miles / kWh (km / kWh), or
Wh per mile (Wh per km) are most pragmatic units.

note: actual BTU of gasoline at the pump is lower than 115,000 BTU due to most pumps delivering an 85-90% blend with ethanol (which lowers actual MPG, as ethanol only has 75,000 BTU per gallon … ~2/3 the energy).

There should be a “Ge” value posted at gas pumps to allow ICE drivers to compare actual fuel use to pure EPA test-grade gasoline used for MPG rating.

Mikael

MPGe should just be removed alltogether. The kWh/100km is more than enough.

And for the americans that are still a few hundred years behind in units and measurements there could be a small notion in kWh/100 miles or so too.

Priusmaniac

No problem with 5 mpkwh neither for example. It could be Shortened in 5 mpk.

Mikael

That is a problem since it has no scientific value. The idea is not to (once again) dumb down the americans but to have them reach higher.

Speculawyer

It has no scientific value? It is just the reciprocal of the figure you asked for.

Nix

There is no doubt that kWh per 100 kilometers is hands down the most accurate unit of measure for efficiency.

But the American Mass Market Consumer dislikes kWh as a unit of measurement even more than they dislike kilometers.

We have as much chance getting the mass market to agree to changing to kilometers as we have getting them to understand kWh’s. Heck, even among EV enthusiasts there is often confusion between kW’s and kWh’s.

What is scientifically the best measure has nothing to do with what is put on these stickers. These stickers should be seen as outreach to the mass market. And you aren’t going to win the mass market by making them feel stupid with units of measure they don’t understand the moment they step up to the side of the car.

DCFC

MPGe is useless imho. Keep it simple!

My Spark EV displays in metric units :
kWh/100kM which is very easy to compare to L/100kM, especially if you want to compare cost per standardized distance, all you need to know is the cost per unit of energy.

Rick

Miles/Dollar is the most useful metric. In the end, it’s what people really want to know if they are going to do some comparison shopping.

Mikael

Neither miles nor dollars are metrics.

Speculawyer

They are both metrics. But dollars is not a good one because prices fluctuate a lot.

Nix

I agree with Speculawyer. And so do all the test groups that the EPA talked to. They don’t want dollars per whatever for either EV’s or gas cars. That’s why gas cars aren’t rated at cents per mile, even though the EPA can provide that number. There are similar dollar per distance numbers on the EPA website for gas cars, but the consumers overwhelmingly told the EPA they wanted MPG instead for gas cars, and MPGe for plugins.

Robert

This sort of video just gives me a headache!
MY diesel car gets 60mpg+
I understand that.
If it was a hybrid, I’d understand that, because as far as I’m concerned, I still put fuel in from the pump and I can work out how many miles I get.
If it was a 100% electric car, I wouldn’t care about miles per GALLON. I would just want to know how much it costs to charge up the batteries and how far I could go.
And as for the mpg per 100kms?
What a load of rubbish. WHICH 100kms? The 100kms driving through town? The 100kms driving along a motorway?
I get 60mpg+ just diving around everywhere!

GSP

MPGe is useless. Just post the kWh/100 miles.

Use the space to post the range for both a standard charge (about 90%), and range charge (100%).

GSP

Lensman

“…should MPGe be replaced with something more useful?”

Well of course it should. Something like miles per 10 kWh would give something not too terribly far away from MPG.

Or, you know, just bite the bullet and use straight miles per kWh; the public will eventually get used to it. After all, those numbers are supposed to be “for comparison purposes only”, just like MPG.

Nix

Lensman — It is a two way street. We want mass market consumers to buy EV’s and PHEV’s. And mass market consumers overwhelmingly told the EPA in study group after study group that they wanted MPGe over anything that used kWh at all.

Since we want something from them (buying plugins), we need to be willing to give them something they want too.

Personally, I’d like the US public to “bite the bullet” and convert to metric and drop miles completely. But I’d rather have them buy EV’s and PHEV’s and lose this battle, rather than force them to bite anything.

Speculawyer

I LOVE the MPGe rating. It does a great job of emphasizing the relative efficiency of electric motors compared to internal combustion engines.

I know, lots of people want miles/KWH . . . well, if you look at the sticker you’ll see that it does provide you with the KWH/100 miles, so just do the reciprocal of that.