Is electric car fuel efficiency a fraud? Leaf gets 25 mpg?

[Aepervius]

The electricity is not counted, not because of fraud or anything, but because what is deemed improtant is how many gallon of GASOLINE is used by the car.

If you really wanted to count a total MPG using other source of energy, then why stop there ? Count the energy lost in the car fabrication, lubrication, maintenance, usage, scraping. Nobody count the equivalent-MPG from hybrid coming outlets because it is misleading. What count to most people buying one is how much it cost, how far and how quick it can go.

It would also be totally misleading because depending on WHERE you are, that would be a horrible calculation. Be in France ? Electricity is nuclear. Be in some part of the US ? Mostly hydro electric. Another part ? Coal. Another ? Nuclear ? Another ? Gas.

The MPG is not supposed to say you how much energy it consume, but how far you go with a gallon of gasoline in the tank.

 

[davefoc]

That makes no sense because almost no electricity is produced by small, inefficient, gasoline-powered generators.



Why is efficiency, by itself, relevant? Waste is only important to the extent that it costs money and pollutes (the same thing, really).

But if one is concerned with cost, it's much better to look at electricity prices directly. The link authors didn't do that.

And if one is concerned with pollution, it's much better to look at the amount of pollution created per kW-h on average, taking into account pollution-free sources like nuclear or hydroelectric. The link authors didn't do that, either.

Efficiency as its own metric is absolutely useless--one may as well say that solar power is 0.0000...00001% efficient because most of the Sun's light doesn't even hit the Earth and is lost into space.

- Dr. Trintignant

The electricity is not counted, not because of fraud or anything, but because what is deemed improtant is how many gallon of GASOLINE is used by the car.

If you really wanted to count a total MPG using other source of energy, then why stop there ? Count the energy lost in the car fabrication, lubrication, maintenance, usage, scraping. Nobody count the equivalent-MPG from hybrid coming outlets because it is misleading. What count to most people buying one is how much it cost, how far and how quick it can go.

It would also be totally misleading because depending on WHERE you are, that would be a horrible calculation. Be in France ? Electricity is nuclear. Be in some part of the US ? Mostly hydro electric. Another part ? Coal. Another ? Nuclear ? Another ? Gas.

The MPG is not supposed to say you how much energy it consume, but how far you go with a gallon of gasoline in the tank.

The use of a metric that equates the chemical energy in a gallon of gas with the the energy available from electricity is technically correct but misleading and that is the point of the article Piggy linked to.

From the user's perspective not all piles of energy are the same even when they contain the same number of joules. Electricity is a particularly good form to have the energy in. You can power very efficient motors with it and get a very good percentage of it turned into the mechanical energy. Gasoline less so. Gasoline engines are just less efficient at producing mechanical energy out of the available chemical energy in gasoline than electric motors are at producing mechanical energy out of electrical energy.

If our electricity was produced via gasoline generators the comparison between electric cars and gasoline cars would be straight forward but still complicated.

Comparison between the environmental impact and the energy consumption of gasoline and electric cars in the real world with different power plant types and different distribution efficiencies and different distances from the power plants is at least very difficult. However, like somebody mentioned above, cost of operation is a lot more straightforward issue to determine and in the end cost of operation will be the main issue that determines if people are going to drive electrical vehicles or not.

 

[gambling_cruiser]

Any agency that pushes electric cars is silent about enviromental problems of the recycling of the batteries. Life cycles are short (about 3 to 5 years).
And france doesn't charge the cost of nuclear waste depostion on the bill for electricity, they use taxes for that.

 

[Dr. Trintignant]

The use of a metric that equates the chemical energy in a gallon of gas with the the energy available from electricity is technically correct but misleading and that is the point of the article Piggy linked to.

No, the point of the article was to allow global-warming-denialist-types to continue thinking that their SUVs are not as wasteful as they seem.

The 25 MPG number they come up with is based on a calculation that has no bearing on reality. The 93 MPG figure from the EPA is by no means the full story, but it at least is based on a straightforward physics calculation, not some cherry-picked worst-case numbers.

There is unfortunately no easy way around the problem. The metric depends on what you think is most important. So ignorant consumers can never be satisfied, because their expectations will always differ from what the metric computes. This is not a new problem--the EPA MPG figures in use today are based on a certain driving pattern, but no one drives in precisely that pattern.

The hope, really, is that the numbers are at least accurate enough for comparative purposes. I see no evidence that the MPGe numbers are not useful for comparison, at least among electrics/plug-in hybrids.

and in the end cost of operation will be the main issue that determines if people are going to drive electrical vehicles or not.

That I can agree with, and if you look at the second link I posted, the EPA is certainly considering adding cost to the labeling requirements. But determining cost is really not that straightforward except in a very average sense. Even if electricity were free it would not be a trivial problem, since you have to figure out how often the vehicle will be in electric vs. gasoline mode.

- Dr. Trintignant

 

[Furcifer]

No, the point of the article was to allow global-warming-denialist-types to continue thinking that their SUVs are not as wasteful as they seem.

I've been called a denialist for my own views on global warming, but I have to agree. Whoever authored this has some agenda, because it isn't even close to being factual.

If everybody went out a bought an electric car today, there may be a problem. But over the course of the next few years the grid capacity to meet the demands of electric cars will be met using technologies a lot cheaper and much cleaner than gasoline.

 

[Piggy]

Well, my point in posing the question was simply to illustrate the complexity in coming up with a useful metric, and how--depending on which choices you make--you could come up with almost any number you wanted.

See this link:
http://www.epa.gov/air/caaac/mstrs/oct2010/1_snapp.pdf

It says "Conversion from kw-hrs to MPGe based on 33.7 kw-hrs/gallon". This is roughly the raw energy content in a gallon of gas, so it appears that that is their basis for the conversion. They don't seem to take anything else into account. The original article seems to be correct at least on that point.

You might also read this link, though:
http://www.epa.gov/fueleconomy/label/420r10909.pdf

Check out the sample labels at the end where they do some cost calculations and have to make assumptions about electricity rates and so on.



It's roughly 4.3 kg of coal per gallon of gas. But this doesn't take efficiency in to account, and how power plants do better than cars in this regard.

If one assumes that all our electricity comes from outdated coal plants, then a "real" number of 25 MPG is perhaps reasonable. And maybe there's some West Virginian city where that's accurate. But everywhere else there is a mix of electrical generation, and so their adjusted number makes no sense there.

- Dr. Trintignant

In that case, you seem to be agreeing with the blogger that the EPA's MPGe figure is rather arbitrary, a stab in the dark at best? Or am I misreading you here.

(I don't care to get into their accusations of "fraud" at the moment, actually, since that's a broader issue which the blogger provides no evidence for.)

 

[Piggy]

Why is efficiency, by itself, relevant? Waste is only important to the extent that it costs money and pollutes (the same thing, really).

But if one is concerned with cost, it's much better to look at electricity prices directly. The link authors didn't do that.

And if one is concerned with pollution, it's much better to look at the amount of pollution created per kW-h on average, taking into account pollution-free sources like nuclear or hydroelectric. The link authors didn't do that, either.

Efficiency as its own metric is absolutely useless--one may as well say that solar power is 0.0000...00001% efficient because most of the Sun's light doesn't even hit the Earth and is lost into space.

The rhetorical purpose of the post seems to be to accuse the EPA and the "mainstream media" (abbreviated MSM) of a willful effort to distort the facts in order to promote a supposedly liberal environmental agenda (for some reason).

As their central point of evidence, they bring up the MPGe figure on the Monroney sticker for electric cars.

If that figure is a stab in the dark, I don't think that actually constitutes evidence of fraud (nor do I think news media have nefarious motives for dropping the "estimated"), but I did want to look at that particular point and see if there was some validity to it.

So far, there has been no ringing endorsement of the number.

 

[Ladewig]

It's true that the car's energy has to come from somewhere. And it's true that a depressing amount of the US energy supply comes from coal. Coal is a major contributor to acid rain, CO2, CO and other really bad byproducts.

However, gasoline engines are also sources of polution, and liberate carbon pretty much the same way coal plants do. As with everything, efficiency is easier at scale. A hundred million small engines are more difficult to correct than 100 coal plants.

As the energy burden shifts from the individual car to the plant, new technologies can make the plants cleaner, more efficient or even obsolete. A gas engine a hundred years from now is still going to burn gas. But your electric sockets don't care whether the wires are bringing in burned gas, coal, natural gas or nuclear, water or wind.

Electric cars will result in lower emissions overall.

Furthermore even if cars and power plants had the exact same amount and type of emissions per unit of energy, it would still be helpful to have this type of car because it transfers the location of emissions. In Mexico city, it is very desireable to not have polluting cars downtown.

[a concession of the point] yes, the number of places in North America where this is measurably helpful represents a tiny, tiny fraction of all auto use.

 

[technoextreme]

Can anyone with expertise in this area chime in and give a layman's explanation of whether these accusations hold water or not?

Pure ******** for a number of reasons. As someone all ready pointed out not all sources of power are accounted for in this claim. Then you have the fact that instead of having thousands of little cars that pollute you have a far easier and managable number of polluters to take car of.
EDIT:
Also, a quick look shows that not all coal power plants are 33% efficient.

 

[Dr. Keith]

In that case, you seem to be agreeing with the blogger that the EPA's MPGe figure is rather arbitrary, a stab in the dark at best? Or am I misreading you here.

I would just point out that if MPGe was the same as MPG it wouldn't need the "e" added.

We require a very structured test to determine the MPG of a vehicle so that we can compare vehicles with rather minor differences. That test does not translate well when we try to apply it to a very different vehicle. The fact that the EPA has even tried to make the comparisons similar is nice, but a better metric is likely to emerge as we have to compare more EVs to one another.

Think of trying to measure the tonnage of an unladen swallow using a truck scale. Not the right tool for the job. Not the right units of measure. It will be of little use to the aviary biologist. (awful analogies are my speciality, btw)

So, use the MPGe to compare one EV to another, but don't think of it as much of a help in picking whether to buy an EV or a diesel. (Diesel is better for highway driving while EVs would be better for stop and go, all other things being equal.)

 

[themusicteacher]

I've often wondered if the pollution generated to charge the car was included in the energy consumption info for electrics or hybrids. I suppose, strictly speaking in MPG (of gasoline), all that matters is whether or not the vehicle uses gas or not and at what rate. I don't think it's dishonest at all to say that a car has a high MPG if it does, indeed, run on only 1 gallon of gas for every 99 miles. That is not a lie if it does so.

 

[69dodge]

That makes no sense because almost no electricity is produced by small, inefficient, gasoline-powered generators.

It would make some sense because at least it would include the inefficiency of some form of conversion of heat into useful energy, which is necessary in any case. The way the EPA does it now, the conversion is assumed to be 100% efficient, which is definitely wrong. The only question is how wrong it is.

Basically, I'm not defending the specific numbers of the webpage quoted in the OP; I'm agreeing with its general point that the EPA's numbers are wrong and with the general reasoning as to why they're wrong.

Why is efficiency, by itself, relevant?

I don't say it is. I was just answering Piggy's question, as I understood it.

 

[69dodge]

The electricity is not counted, not because of fraud or anything, but because what is deemed improtant is how many gallon of GASOLINE is used by the car.
[...]
The MPG is not supposed to say you how much energy it consume, but how far you go with a gallon of gasoline in the tank.

No. The Nissan Leaf is all-electric. It uses no gasoline at all. But the EPA doesn't rate it as getting infinitely many miles per gallon.

 

[technoextreme]

So, use the MPGe to compare one EV to another, but don't think of it as much of a help in picking whether to buy an EV or a diesel. (Diesel is better for highway driving while EVs would be better for stop and go, all other things being equal.)

Actually all things being equal electric vehicles will always be superior than the ICE. Electric motors are better in every way shape and form for transportation purposes when compared to an ICE. The major failing being that batteries when compared to gasoline sucks.

 

[drkitten]

Can anyone with expertise in this area chime in and give a layman's explanation of whether these accusations hold water or not?

Thanks.

I would say not, for the simple reason that they're trying to charge electric vehicles with the cost of delivering energy from the production site to the car, but trying to avoid doing the same for gasoline vehicles.

The gas at your local Exxon station didn't come from there; it arrived by truck or pipeline, with all the transportation costs. It didn't come from the pump in nice clean form, but was refined at a huge inefficient building at substantial energy cost. But what you care about at the pump is how many miles you get for how many gallons you pump. Everything else is folded into the cost of gasoline; you might actually pay for a gallon of diesel for every five gallons you pump, but the magic of amortization makes it go away.

Similarly, the question is how many miles you can drive for each gallon-equivalent number of kWh you put into the electric vehicle; if you've got a really inefficient local power plant, then you'll simply pay more per kWh reflecting the additional cost.

 

[davefoc]

No [referring to davefoc's claim that the point of the article was that the EPA mileage estimate for electric vehicles was misleading], the point of the article was to allow global-warming-denialist-types to continue thinking that their SUVs are not as wasteful as they seem.

That very well may be the case and when I said the point of the article was to point out that the EPA mileage estimate for electric vehicles was misleading I was probably wrong. However the EPA mileage estimate for electric vehicles is misleading as 69dodge has explained in a couple of his posts even if that wasn't the point of the article.

I think that drkitten's point is correct that if one was trying compare the societal costs of electric vehicles one would need to take many things into account that the article didn't including the costs of gasoline distribution, the costs of electric power distribution, pollution, power plant fuel, etc.

 

[69dodge]

Similarly, the question is how many miles you can drive for each gallon-equivalent number of kWh you put into the electric vehicle; if you've got a really inefficient local power plant, then you'll simply pay more per kWh reflecting the additional cost.

It sounds like you think that the main purpose of the sticker is to make it easy for buyers to calculate how much money it will cost them to run the car. In that case, the question for electric cars is how many miles the car will go for each kilowatt-hour of electricity used, because electricity is sold by the kilowatt-hour. (Fortunately, this information is also listed on the sticker, in the form of kilowatt-hours per 100 miles.) What is the significance of a gallon-equivalent number of kilowatt-hours, and of the derived MPGequivalent figure? It only invites dubious comparisons to gasoline-powered cars.

 

[Weak Kitten]

I know this is a bit off topic but are articles like this helpful or harmful to the development of new and better technologies?

Does it encourage new and positive changes or does it discourage new ideas by seriously tearing them apart while they are still in their infancy?

 

[Dr. Keith]

Actually all things being equal electric vehicles will always be superior than the ICE.

Ouch, "always" is "never" the right word to use . . .

For example, let's say you routinely drive a 250 - 450 mile round trip with 90% of that being on freeways at 70 mph. Which car would you find best?

I think a jetta diesel gets you there in back in one tank, maybe two, and at over 45 mpg. The Leaf will take you an extra day or two, depending on how you space the charging. The Prius will do it in two tanks, but the mileage will be lower than the jetta.

Electric motors are better in every way shape and form for transportation purposes when compared to an ICE.

I can totally agree with that. But there is a difference between a motor and a vehicle . . .

The major failing being that batteries when compared to gasoline sucks.

And that is the difference between an EV and diesel vehicle.

 

[AvalonXQ]

Someone else said that miles per dollar of fuel was a good number to use for equivalency; I tend to agree.
Since most of us are pretty familiar with MPG, we could divide miles/dollar by the cost of a gallon of gas to get equivalent MPG on a metric that actually matters for consumers.
Personally, the three numbers I would want you to tell me for an electric car are miles/charge, dollars/charge, and length of time to charge.