Posts tagged ‘Nissan Leaf’

Bringing Skepticism (and Math) to Electric Vehicle Fuel Numbers

Frequent readers of this blog will know that I am enormously skeptical of most fuel and efficiency numbers for electric vehicles.  Electric vehicles can be quite efficient, and I personally really enjoy the driving feel of an electric car, but most of the numbers published for them, including by the government, are garbage.  I have previously written a series of articles challenging the EPA's MPGe methodology for electric cars.

In just a bit, I am going to challenge some numbers in a recent WSJ article on electric vehicles, but first let me give you an idea of why I don't trust many people on this topic.  Below is a statement from Fueleconomy.gov, which bills itself as the official government source for fuel economy information (this is a public information, not a marketing site).  In reference to electric vehicles, it writes this:

Energy efficient. Electric vehicles convert about 59–62% of the electrical energy from the grid to power at the wheels—conventional gasoline vehicles only convert about 17–21% of the energy stored in gasoline to power at the wheels

The implication, then, is that electric vehicles are 3x more energy efficient than cars with gasoline engines.  I hope engineers and scientists can see immediately why this statement is total crap, but for the rest, here is the problem in short:  Electricity has to be produced, often from a fossil fuel.  That step, of converting the potential energy in the fuel to use-able work, is the least efficient step of the entire fuel to work process.  Even in the most modern of plants it runs less than a 50% conversion efficiency.   So the numbers for the gasoline cars include this inefficient step, but for the electric vehicle it has been shuffled off stage, back to the power plant which is left out of the calculation.

Today I want to investigate this statement, which startled me:

Factor in the $200 a month he reckons he isn't paying for gasoline to fill up his hulking SUV, and Mr. Beisel says "suddenly the [Nissan Leaf] puts $2,000 in my pocket."

Yes, he pays for electricity to charge the Leaf's 24-kilowatt-hour battery—but not much. "In March, I spent $14.94 to charge the car" and a bit less than that in April, he says.

This implies that on a cost-per-mile basis, the EV is over 13x more efficient than gasoline cars.  Is this a fair comparison?  For those who do not want to read a lot of math, I will preview the answer:  the difference in fuel cost per mile is at best 2x, and is driven not by using less fossil fuel (the electric car likely uses a bit more, when you go all the way back to the power plant) but achieves its savings by using lower cost, less-refined fossil fuels  (e.g. natural gas in a large power plant instead of gasoline in a car).

Let's start with his estimate of $14.94.  Assuming that is the purchased power into his vehicle charger, that the charger efficiency is 90%, and the cost per KwH in Atlanta is around $0.11, this implies that 122.24 use-able KwH are going into the car.  Using an estimate of 3.3 miles per KwH for the Leaf, we get 403 miles driven per month or 3.7 cents per mile in electricity costs.  This is very good, and nothing I write should imply that the Leaf is not an efficient vehicle.  But its efficiency advantage is over-hyped.

Now let's take his $200 a month for his Ford Expedition, which has an MPG around 15.  Based on fuel prices in Atlanta of $3.50 a gallon, this implies 57 gallons per month and 857 miles driven.  The cost is 23.3 cents per mile.

Already we see one difference -- the miles driven assumptions are different.  Either he, like a lot of people, don't have a reliable memory for how much he spent on gas, or he has changed his driving habits with the electric car (not unlikely given the shorter range).  Either way, the total dollar costs he quotes are apples and oranges.  The better comparison is 23.3 cents per mile for the Expedition vs. 3.7 cents a mile for the Leaf, a difference of about 6x.  Still substantial, but already less than half the 13x difference implied by the article.

But we can go further, because in a Nissan Leaf, he has a very different car from the Ford Expedition.  It is much smaller, can carry fewer passengers and less cargo, cannot tow anything, and has only 25% of the Expedition's range.   With an electric motor, it offers a very different driving experience.   A better comparison would be to a Toyota Prius, the c version of which gets 50MPG.  It is similar in most of these categories except that it has a much longer range, but we can't fix that comparison, so just keep that difference in mind.

Let's look at the Prius for the same distances we calculated with his Leaf, about 403 miles.   That would require 8.1 gallons in a Prius at $3.50, which would be $28.20 in total or 7 cents a mile.  Note that while the Leaf still is better, the difference has been reduced to just under 2x.  Perhaps more importantly, the annual fuel savings has been reduced from over $2200 vs. the Expedition that drove twice as many miles to $159 a year vs. the Prius driving the same number of miles.  So the tradeoff is $159 a year savings but with much limited range  (forgetting for a moment all the government crony-candy that comes with the electric car).

$159 is likely a real savings but could be swamped by differences in long-term operating costs.  The Prius has a gasoline engine to maintain which the Leaf does not, though Toyota has gotten those things pretty reliable.  On the other hand the Leaf has a far larger battery pack than the Prius, and there are real concerns that this pack (which costs about $15,000 to manufacture) may have to be replaced long before the rest of the car is at end of life.  Replacing a full battery pack after even 10 years would add about $1200 (based on discounted values at 8%) a year to operating costs, swamping the fuel cost advantage.

Also note that a 2x difference in fuel costs per mile does not imply a 2x difference in fuel efficiency.  Gasoline is very expensive vs. other fuels on a cost per BTU basis, due to taxes that are especially high for gasoline, blending requirements, refining intensity, etc.)  Gasoline, as one person once said to me way back when I worked at a refinery, is the Filet Mignon of the barrel of oil -- if you can find a car that will feed on rump steak instead, you will save a lot of money even if it eats the same amount of meat.    A lot of marginal electric production (and it is the margin we care about for new loads like electric cars) is natural gas, which is perhaps a third (or less) the cost of gasoline per BTU.   My guess is that the key driver of this 2x cost per mile difference is not using less fuel per se, but the ability to use a less expensive, less-refined fuel.

Taking a different approach to the same problem, based on the wells-to-wheels methodology described in my Forbes article (which in turn was taken directly from the DOE), the Nissan Leaf has a real eMPG of about 42 (36.5% of the published 115), less than the Prius's at 50.  This confirms the findings above, that for fossil fuel generated electricity, the Leaf uses a bit more fossil fuels than the Prius but likely uses much less expensive fuels, so is cheaper to drive.  If the marginal electrical fuel is natural gas, the Leaf also likely generates a bit less CO2.

Electric Vehicle Welfare Queen

No, we are not talking today about Elon Musk (though the name fits) but about this electric car buyer profiled in the WSJ:

Bronson Beisel, 46, says he was looking last fall for an alternative to driving his gas-guzzling Ford Expedition sport utility around suburban Atlanta, when he saw a discounted lease offer for an all-electric Nissan Leaf. With $1,000 down, Mr. Beisel says he got a two-year lease for total out-of-pocket payments of $7,009, a deal that reflects a $7,500 federal tax credit.

As a resident of Georgia, Mr. Beisel is also eligible for a $5,000 subsidy from the state government. Now, he says, his out-of-pocket costs for 24 months in the Leaf are just over $2,000. Factor in the $200 a month he reckons he isn't paying for gasoline to fill up his hulking SUV, and Mr. Beisel says "suddenly the car puts $2,000 in my pocket."

Yes, he pays for electricity to charge the Leaf's 24-kilowatt-hour battery—but not much. "In March, I spent $14.94 to charge the car" and a bit less than that in April, he says. He also got an electric car-charging station installed at his house for no upfront cost.

"It's like a two-year test drive, free," he says.

I hope you all enjoy Mr. Beisel's smug pride a driving a car using your money.

In my next post, I am going to dive deeper in the operating cost numbers here.  By the article, Mr. Beisel has cut his monthly fuel costs from $200 to $14.94, a savings of over 90%.  If these numbers are real, why the hell do we have to subsidize these cars?  Well, while it turns out that while the Leaf is a nice efficient vehicle, these numbers are way off.  Stay tuned.

Update on the EPA's Electric Vehicle Mileage Fraud

I have written several articles (here and here) outlining why the EPA's method of giving electric cars an equivalent or eMPG is outright fraudulent.  I calculated for the average driver, for example, that the Nissan Leaf's 99 eMPG was actually closer to 36.  Why?  Well, in the EPA's methodology, the science-based Obama administration pretends the 2nd law of thermodynamics does not exist.  Specifically, they assume perfect conversion of the chemical potential energy in fossil fuels to electricity.  They also assume zero transmission losses.  To rework the calculation, I actually used a Clinton-era Department of Energy methodology called well to wheels.

So here is something I thought I would never write:  It turns out the Union of Concerned Scientists agrees with me.  Apparently they have used a similar methodology to rework electric vehicle MPGs based on the fuel mix of the power in different cities, rather than an average national fuel mix as I did it.  I am not sure how they did the analysis - did they use average fuel mix or the marginal fuel, and if the marginal fuel did they assume the marginal fuel at night or during the day?   For example, certain California cities look good with solar use but that does not do anything for typical night time car charging.

Anyway, the problem is hard and I could quibble with how they did it.  But the results are telling - everywhere they looked, even in the hydro-powered Pacific Northwest, the eMPG they got was lower than that of the EPA's.  And in many cases much lower.

If corporations were using the EPA's eMPG methodology, they would be busted by the FTC for false advertising.  It's time to fix this calculation so Fisker Karma drivers can't continue to fool themselves into thinking they are doing something positive for the environment.

Mandating Faulty Accounting to Reach Absurd MPG Standards

President Obama wants a 56.2 mile per gallon standard for cars by 2025.  Both advocates and opponents of this say the only way to make this is if everyone drives an electric car or plug in hybrid.  But the fact of the matter is, even those don't get 56.2 mpg, except through an accounting fiction.

A while back I ran the numbers on the Nissan Leaf. According to the EPA, this car gets an equivalent of 99 MPG.  But that is only by adopting the fiction of looking only at the efficiency in converting electricity to power in the wheels.  But the electricity comes from somewhere (the marginal kilowatt almost certainly comes from a fossil fuel) and the new EPA methodology completely ignores conversion efficiency of fuel to electricity.  Here is how I explained it at Forbes:

The problem is that, using this methodology, the EPA is comparing apples to oranges.   The single biggest energy loss in fossil fuel combustion is the step when we try to capture useful mechanical work (ie spinning a driveshaft in a car or a generator in a power plant) from the heat of the fuel’s combustion.  Even the most efficient processes tend to capture only half of the potential energy of the fuel.   There can be other losses in the conversion and distribution chain, but this is by far the largest.

The EPA is therefore giving the electric vehicle a huge break.  When we measure mpg on a traditional car, the efficiency takes a big hit due to the conversion efficiencies and heat losses in combustion.  The same thing happens when we generate electricity, but the electric car in this measurement is not being saddled with these losses, even though we know they still occur in the system.

Lets consider an analogy.  We want to measure how efficiently two different workers can install a refrigerator in a customer’s apartment.  In both cases the customer lives in a fourth floor walkup.  The first installer finds the refrigerator has been left on the street.  He has to spend much of his time struggling to haul the appliance up four flights of stairs.  After that, relatively speaking, the installation is a breeze.  The second installer finds his refrigerator has thoughtfully been delivered right to the customer’s door on the fourth floor.  He quickly brings the unit inside and completes the installation.

So who is a better installer?  If one only looks at the installer’s time, the second person looks orders of magnitude better.  But we know that he is only faster because he offloaded much of the work on the delivery guys.  If we were to look at the total time of the delivery person plus the installer, we’d probably find they were much closer in their productivity.  The same is true of the mileage standards — by the EPA’s metric, the electric vehicle looks much better than the traditional vehicle, but that is only because someone else at the power plant had to do the really hard bit of work that the traditional auto must do itself.  Having electricity rather than gasoline in the tank is the equivalent of starting with the refrigerator at the top rather than the bottom of the stairs.

The DOE has actually published a better methodology, going from "well to wheels," creating a true comparable efficiency for electric cars to gasoline engine cars.  By this methodology, the Nissan Leaf all electric car only gets 36 MPG!  In fact, no current electric car would meet the 56.2 MPG standard if the accounting were done correctly.  Which is why the EPA had to create a biased, inaccurate MPG equivalent measure for electric vehicles to artificially support this Presidential initiative.

Rent-Seeking Gold Rush

The Thin Green Line reports that Renault recently fired a number of employees for espionage related to electric vehicles.  The site concludes:

The stakes are high: The French automaker, now partnered with Nissan, is betting its future on the popularity of the electric vehicle. It plans to introduce no fewer than three electric cars in Europe this year: a sedan, a light commercial vehicle, and a city car.

Unless the espionage thwarts its plans, Renault's gamble is probably a good one. Also last week, the judges of the Detroit auto show gave all their top awards to EVs and hybrids — proof, according the Guardian, that "analysts [are] bet[ting] on rising oil prices and wider acceptance of electric cars." Nissan's Leaf took second place to the Chevy Volt.

As I wrote in the comments, electric cars are a huge opportunity - there are tens of billions of dollars of corporate welfare from countries around the world to be captured. When it is the Left that is actively supporting huge transfers of funds from taxpayers to large corporations, that is an unprecedented rent-seeking opportunity that European companies, already well-schooled in how to be successful within a corporate state, are sure to avidly pursue. Not since corn ethanol has there been a similar gold-rush for taxpayer funds.

More Thoughts on EV MPG

After several posts yesterday, I rewrote my thoughts on EV's and the new EPA mileage numbers.  I am more convinced than ever that this standard borders on outright fraud, particularly when the DOE published what should be the correct methodology way back in the Clinton Administration and the EPA has ignored this advice and gone with a methodology that inflates the MPG (equivilant) of EV's by a factor of nearly 3.  For example, the list the Nissan Leaf with an MPGe of 99, but by the DOE methodology the number should be 36.

The full article is in Forbes.com and is here.  An excerpt:

The end result is startling.  Using the DOE's apples to apples methodology, the MPGe of the Nissan Leaf is not 99 but 36! Now, 36 is a good mileage number, but it is pretty pedestrian compared to the overblown expectations for electric vehicles, and is actually lower than the EPA calculated mileage of a number of hybrids and even a few traditional gasoline-powered vehicles like the Honda CR-Z.

Supporters of the inflated EPA standards have argued that they are appropriate because they measure cars on their efficiency of using energy in whatever form is put in their tank (or batteries).  But this is disingenuous.  The whole point of US fuel economy standards is not power train efficiency per se, but to support an energy policy aimed at reducing fossil fuel use.  To this end, the more sophisticated DOE standard is a much better reflection of how well the Nissan Leaf affects US fossil fuel use.  The only reason not to use this standard is because the EPA, and the Administration in general, has too many chips on the table behind electric vehicles, and simply can't afford an honest accounting.

Nissan Leaf EPA Rating Hugely Flawed

Update: True MPGe is closer to 36, see below.  The 36 actually comes from the government's own research and rule-making, which they have chosen to ignore.

The EPA has done the fuel economy rating for the all-electric Nissan Leaf.  I see two major problems with it, but first, here is the window sticker, from this article

Problem #1:  Greenhouse gas estimate is a total crock.  Zero?

The Greenhouse gas rating, in the bottom right corner, is that the car produces ZERO greenhouse gasses.  While I suppose this is technically true, it is wildly misleading.  In almost every case, the production of the electricity to charge the car does create greenhouse gasses.  One might argue the answer is zero in the Pacific Northwest where most power is hydro, but even in heavy hydro/nuclear areas, the incremental marginal demand is typically picked up by natural gas turbines.  And in the Midwest, the Leaf will basically be coal powered, and studies have shown it to create potentially more CO2 than burning gasoline.  I understand that this metric is hard, because it depends on where you are and even what time of day you charge the car, but the EPA in all this complexity chose to use the one number - zero - that is least likely to be the correct answer.

Problems #2:  Apples and oranges comparison of electricity and gasoline.

To understand the problem, look at the methodology:

So, how does the EPA calculate mpg for an electric car? Nissan's presser says the EPA uses a formula where 33.7 kWhs are equivalent to one gallon of gasoline energy

To get 33.7 kWhs to one gallon, they have basically done a conversion through BTUs -- ie 1 KWh = 3412 BTU and one gallon of gasoline releases 115,000 BTU of energy in combustion.

Am I the only one that sees the problem?  They are comparing apples and oranges.  The gasoline number is a potential energy number -- which given inefficiencies (not to mention the second law of thermodynamics) we can never fully capture as useful work out of the fuel.  They are measuring the potential energy in the gasoline before we start to try to convert it to a useful form.  However, with electricity, they are measuring the energy after we have already done much of this conversion and suffered most of the losses.

They are therefore giving the electric vehicle a huge break.  When we measure mpg on a traditional car, the efficiency takes a hit due to conversion efficiencies and heat losses in combustion.  The same thing happens when we generate electricity, but the electric car in this measurement is not being saddled with these losses while the traditional car does have to bear these costs.  Measuring how efficient the Leaf is at using electricity from an electric outlet is roughly equivalent to measuring how efficient my car is at using the energy in the drive shaft.

An apples to apples comparison would compare the traditional car's MPG with the Leaf's miles per gallon of gasoline (or gasoline equivalent) that would have to be burned to generate the electricity it uses.  Even if a power plant were operating at 50% efficiency (which I think is actually high and ignores transmission losses) this reduces the Leaf's MPG down to 50, which is good but in line with several very efficient traditional cars.

Update: I have new numbers, which in part help respond to the first commenter.   The short answer to his comment is that there is a big difference between handwaving away10% you missed and handwaving away 70%.  I agree that the EPA numbers for the Leaf are valid "tank-to-wheel" numbers (meaning how efficiently does the car use the energy in its tank).  The question is, whether tank-to-wheel has any meaning at all.  My article above is basically an argument for why it is not valid.  Here is an extreme example -- what if we ran cars off of replaceable flywheels that were spun up by third parties and then put in our cars already energized.  These would be highly efficient on a tank to wheel basis, as we just need to transmit what is already mechanical energy to the wheels.  But does ignoring the energy costs and inefficiencies in spinning these things up offline really make sense?

We can go to the government itself to solve this.  In this rule-making document, the DOE defines some key numbers we need here.

They define petroleum refining and distribution efficiency as .83, meaning it takes 1 gallon of gas out of the well to get .83 in your tank.

For electricity, they define two numbers that must be multiplied together.  The fossil fuel electrical generation efficiency is .328 and the transmission efficiency is .924, for a net of .303.

Note the big freaking difference between .83 and .303, which is why to call it all handwaving is disingenuous.  Sure, we often handwave away the fossil fuel cost of getting gas in our cars, but the fossil fuel cost of getting electricity in the batteries is four times higher.   The government even does the math, multiplying the 33.7 Kwh/gal used above by .303 and dividing by .83 to get an apples to apples well to wheels mpge number for electric vehicles of 12.3 Kwh/gal.

So a total apples to apples comparison factor already exists, and the government chose not to use it for the window stickers.  This is probably because it would have given the Nissan Leaf an mpge of 36, not bad but fairly pedestrian for such an overhyped technology.  And at some level the Leaf is irrelevant.  This entire process has likely been tilted to make the Government Motors Volt look better.