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.

  • http://matthewjudebrown.com/ Morven

    Kudos for a thorough analysis of this.

    Note also that the Expedition probably rewards lead-footed driving in a way the Leaf does not, so he may have been getting worse mileage from it than the published figures.

  • Chris Kahrhoff

    I understand and agree with your analysis. What do you think of electric in a place like where we live (Phoenix) where the majority of our power is nuke? Or a different place near hydro?

  • bob loblaw

    You're making the same mistake as those you criticize: when comparing the Leaf to the Prius, you're omitting the cost of the Prius's electricity.

  • Ben

    No he's not -- the Prius generates electricity through braking. Or, to put it another way, the cost of the electricity for the Prius is the cost of its gasoline.

  • Ben

    This is a great analysis -- very fair and very informative in my eyes

  • Curtis

    There is excess electricity at night in most places because
    electricity demand is lower and power plants cannot really be turned
    off. Charging an electric car at night is basically storing excess (virtually free) energy in the car's battery. As long as electric vehicle are rare and charged at night, they are extremely efficient. If a car is charged during the day, the analysis sounds correct.

  • AA

    rhetorical Q: hwo much electricity is spent on producing petrol/fuel?

  • http://twitter.com/justintempler Justin Templer

    Electric cars also enjoy a tax subsidy by not having to pay fuel taxes that are used by governments to fund road construction and maintenance. You can be sure that if enough people were to switch from gasoline/diesel to electric that a tax on electricity for transportation would soon follow.

  • Joe_Da

    Depending on the efficiency of the power plant, approx 25-40% of the energy is lost, ie not converted into electricity, (the common estimate is 1/3 of lost energy. Another one-third of the electrical power is lost in the transmission of electricity via the power lines. the greater the distance of travel, the greater the lose of power.

  • Richard

    Warren,

    Here back home gas is somewhere around 9 usd a gallon. I live in the netherlands. The result is very simple: I dive a car that (really) does 50 mpg. It's not a hybrid but a daihatsu, a 3 cylinder, 1 liter engine. And it weights 720 kg.

    And, best of all, i cycle to work. It's even faster!

  • http://unix-jedi.livejournal.com Unix-Jedi

    Just as a datapoint, driving a early Insight with a old, busted battery pack, I'm charging it overnight with a "Grid charger". According to my Kil-A-Watt meter, that costs about $.30-.50 a night. (I'm into the car + charger for less than $2500 - and having driven it a year, it's paid for itself.)

    No apples-to-apples comparison (and excluding a lot of Insight-specific details), that almost-nightly charging gives me about a 5 MPG difference in driving. Just driving on the gas engine alone I was seeing about 45 MPG, with the battery enabled and charged, I can see about 63.

  • http://unix-jedi.livejournal.com Unix-Jedi

    It's more of a question of, will the current crop suit your needs?
    OTOH, the infrastructure may not be able to handle lots more people charging overnight - the current grid is built with many assumptions and estimates, and overnight charging can totally throw those off.

  • http://unix-jedi.livejournal.com Unix-Jedi

    Starting to drive the Insight last year, where there's a cumulative MPG (updated each minute) as well as an instant sliding-bar MPG gauge, I can tell you I was *much* more aware of lead-footing in a way I've never been before. Friends driving Honda Fits with the same gauge say it's affected their driving. One covered up the gauge with some tape as a test, and found his MPG dropped 5 MPG in in-town driving over a week.

  • Jess1

    You mean the electricity required to refine & deliver NG to the various power stations?

  • Dwight

    A simple way to prove your point is to give each side a container with a gallon of gas and see how far each car will go on that gallon. After all it is equivalent miles per gallon. This takes all the slight of hand out of the picture.

  • TM

    Already happening. NC's new budget includes a proposal for $100/yr tax on EV/Hybrids

  • Jess1

    What exactly is "virtually free" energy? As long as the boilers are fired up & the turbines spinning, it's costing $$$. True, it would be more expensive to shut down & restart, let's not be foolish and think that bedded down operations are somehow "free" or that the electricity produced is not sold for a profit.

  • Broccoli

    Natural gas is not refined. Some natural gas comes out of the ground ready for the turbine with no extra processes. But typically you will have a process to remove liquid and vapor water, heavier hydrocarbons like propane, butane, etc., and sometimes you will have to remove H2S through an amine plant. This is absolutely a pittance compared to what it takes to refine crude oil into its useable parts like diesel, kerosene, and gasoline.
    But lifecycle costs and efficienciese are important to consider, and it can be a never ending rabbit hole if you start talking about drilling costs, drilling emissions, transportation costs, etc. On the renewable side, you have to consider the manufacturing costs, manufacturing emissions, use of plastics, and the costs of use of backup power during the times the renewables aren't generating enough.
    The easiest way to boil down it all is in the simple price per BTU of that form of energy in the absence of subsidies or taxes. That will account for every input cost, efficiency, etc. Unfortunately, with our current cronyist and fascist economic model worldwide, it is becoming just as hard to understand all the distortions in price as it is to try to manually calculate every efficiency of the supply chain.

  • Jess1

    "Natural gas is not refined"

    After that gem of colossal ignorance, it's pretty easy to ignore the rest.

    Of course, the processes are not identical, but there's a great deal to be done before use (BTW, there's a straddle plant on a line @ the farm. Pretty cool operation. Runs on electricity)

  • Earl Wertheimer

    Local paper ran an article comparing cloth diapers to disposables. They compared purchase cost, 'footprint', energy used, resources consumed, disposal costs, etc. Of course the numbers were distorted (cloth claimed 4-8 changes per day vs 4,000 to 7,000 disposables over 2 years).. 2 years = 365 x 2 = 730 days at 8 per day is only 5,840 for 2 years, not the claimed 7,000.. The actual number starts at about 10 per day for newborns and falls to 4 to 6 after a year.

    They made it look like cloth had huge cost savings.

    The best part was the stuff they ignored: Convenience, smell, handling, portability, etc.

    Same with these EV stats. If you really wanted to reduce your "carbon footprint" and your time was worth nothing, you would just walk to your destination. That's the way they did it "in the good old days".

  • obloodyhell

    I believe your numbers are substantially off. Conversion efficiencies are more like the inverse of what you say, 25-40% is the nominal best result for energy conversion (keyword: "Carnot cycle") and the best possible in actual practice appears to be in the 60-65% range -- that is, for every BTU of energy going in, you're getting not more than .6 BTU coming back out. The rest is paid in taxes to the Law of Entropy.

    Moreover, my own investigation as to transmission efficiency is ca. 7% losses -- As of 1995, these were about 7.2% -- that is, for every 1kW you pump into the grid, your plug at the other end only gets about 928 watts out.

  • obloodyhell

    LOL, if you're looking for an answer, it's not "rhetorical". :-D

    Are you referring to the issue of transport expense for fuel to the fueling stations around the corner, compared, presumably, to the cost of transport of fuel to power plants?

    This does seem like a reasonable question, and, unfortunately, is very subject to a heck of a lot of variables -- distance to port, presence/absence of a pipeline, etc. So a hard and fast answer is unlikely. But is almost certainly reflected in the actual cost of a gallon of gas, for the example of automobiles.

  • obloodyhell

    As Jess notes, there is no such thing as "virtually free" energy. Yes, you are correct, the energy produced at night is and should be cheaper since it's reflected in the lower demand vs. the need to keep the generators spinning 24/7/365.25, but this would and could be dealt with by the simple matter of arranging for a variable cost-per-kW at different times of the day, already offered in most, if not all, areas. You could then calculate it using the energy costs of the best off-peak rates.

    So this would be your "optimal" price example. But it's hardly "virtually free" by any meaningful definition of the term.

  • obloodyhell

    }}} you would just walk to your destination

    No, wait. How much would this increase your food costs and your medical bills (after you caught pneumonia walking home in a blizzard)?? :-D

    TANSTAAFL!!

  • ex-army mariner

    I once was mate on a diesel-electric tugboat. Very smooth operation throughout the power range, especially going from reverse to forward and back again, but the lousiest fuel comsumption in the fleet. First you burn the fuel in the main engine (chemical energy to mechanical) that generates electricity (mechanical energy is converted to electrical energy) that is transmitted to a huge electric motor (electrical energy converted to mechanical energy) that drives the prop. We started out with 2400 hp and ended up with 1800 at the propeller. I fail to see how an electric car, with power originating at a power plant, shipped X number of miles, converted to chemical energy in a battery, then reconverted to electric energy, then to mechanical energy, can be a net savings.

  • rxc

    This is a VERY important point, if the progressives want to push us towards more electric cars. They will have to agree with a lot more generating capacity, but also a significant increase in transmission, which is even more difficult (from a social perspective) than generation. Then there would be counter-arguments about "smart-grid" management and demand-shedding, etc. All aspects of control over the consumer, which is where they really want to go - only provide electric (and political) power to those who the progressives "feel" should need it. Everyone else can just get by or do without.

  • rxc

    There is a problem with using just marginal costs of electricity in these calculations. FIrst of all there are transmission issues, but then, even if you talk about using hydro or nuclear, you need to consider the cost of the new generation that would be required. Total hydro capacity in the US is decreasing, I think, because they are decommissioning dams, and no one want to build any more, unless they are very small, almost toys. And nuclear won't be built as long as gas prices are where they are. New generation capacity is expensive

    I would favor a steady nuclearization of the energy stream, starting with electricity and moving to Coal-to-Liquid plants, for which nuclear could provide the heat energy. I think that burning gas to generate electricity is a real sin, almost in the biblical sense of the word, because it is such a valuable material for all sorts of other applications, and dumb heat energy is readily available from other sources (NOT renewables, which are a joke). The Chinese are starting some major CTL plants, burning more coal for the heat, and it will not be long before they decide to use nuclear process heat. The PBMR that they are supposed to be trying out would be a good source of high-temperature energy for CTL.

    Governments in the west seem to be intent on doing to ourselves what some advisors to President Roosevelt (PBUH) wanted to do to Germany after WWII - completely de-industrialize the country and turn it into a pastoral countryside. They were wrong, and the progressive greens are also wrong. We can only hope that they will not succeed.

  • Benjamin Cole

    Electric cars?

    Peanuts.

    Think about the 800,000 barrels---that'd barrels---a day foisted on American consumers and businesses by federal fiat, and after you subsidize production of corn.

    GOP dayglo bright pinko-moonshine, high grade, and untold billions of dollars into the pockets of rural interests.

    Actually, much of the federal government is just a transfer of wealth and income to rural areas.

    But that is not a topic of conversation.....

  • stephana

    Ah the nissan leaf. I saw one on the side of the freeway, about 3 miles short of the exit one day. New car, new temp tag, the whole nine yards. Saw the same car the next day, about 1 mile short of the freeway exit. I guess the car was not made for this persons commute since it did not get them home. I hope he got his money back.

  • effinayright

    I am sure he means "not refined" in terms a chemical engineer would, a process involving "cracking" petroleum into simpler products with differing molecular weights. Gasoline is a product of such refinement.

    You don't need to "refine" natural gas in that sense: it comes out of the ground with the same molecular weight as it's used. Yes, its impurities need to be removed, but that's a far cry from the process used to produce gasoline from crude oil.

  • franksalterego

    Here's something that may be overlooked in the calculations... I used to work at the oil refinery at Avon, Calif. so I know this as fact.

    The oil refinery used waste gases to generate power to run the refinery, and the excess power was put into the electrical grid... So, not only was the refinery producing all kinds of petroleum products, (gasoline, propane, butane, turbine oil, motor oil, several types of grease, and raw materials for other industries) it was also producing electrical energy.

  • Evan Dickinson

    The main point is that a small engine in a car is not going to be as efficient as a generator at a static factory. I'm not an engineer, but this is what I heard. Perhaps the scale leads to greater efficiency.

  • ss396

    True, although demand drops significantly during the night, and the power companies scale back delivery accordingly. But there is a lot of spare generating capacity during the night, and it would not take major capital expansion to kick up the nighttime power delivery. Whether there is enough spare capacity, or whether they will have to add capacity, will depend on how quickly or how slowly the car-recharging demand grows.

    Of course, there is an evening peak demand when everyone comes home from work - which is when they'd want to plug in their cars for recharging. People whose batteries are low are not going to want to wait for the demand drop-off (past midnight?) to recharge their cars. They will want to charge them immediately because you never know when an emergency will happen. So the evening peak demand could easily get worse - and that WILL take major capital expansion to provide for it.

    Good luck to the power companies in managing their way through all this.

  • http://www.itsaboutliberty.com/ Max Artifice

    The electric car is a non-starter for anyone other than vanity owners until they solve three massive problems:

    1) Battery technology that allows you to drive many hundreds of miles on a single charge,

    2) Charging technology that allows for a five minute empty-to-full charging time and

    3) Some way to prevent the car occupants from freezing to death in the winter.

  • common sense

    to rural areas?!

    Weird thing to point out when there is much much much more wealth transferred from workers to non-workers (many of whom live in cities / suburbs) via welfare and the "safety net"

    But I agree, the government's main focus is taking money from some people and giving it to others. I think it's sick and shouldn't happen at all. Ethanol is a terrible fuel, the market does not think its efficient and if Iowa was not the first state to vote, we would have never had anything to do with such a stupid idea.

  • common sense

    Eh, yes and no. If power plants burned gasoline to power our houses, we'd get way less bang for our buck then we do in our cars with their small engines.

    However, burning gas in a huge generating station is more efficient then burning gas in a small generator for your house.

    But any net savings in efficiency are lost in transporting the electricity from the power plant to your house over copper / aluminum wiring. Every step of conversion of energy loses efficiency. I don't know the exact numbers, but if a power plant generates x kilowatt hours of energy, by the time it reaches your house its x-whatever, which will be a much smaller number.

    Gasoline engines are very efficient compared to most ways of generating mechanical power in general, which is why the vast majority of cars are run on gasoline (or diesel)

  • common sense

    well unless your plan is to pour that gasoline in a generator then plug your car into said generator, i'm not sure how you plan on making an electric car run off of gasoline.

    and gasoline generators are nowhere near as efficient as car engines.

  • common sense

    in every state i know of, the gas tax is treated like any other tax and just goes into the maw that are the state general accounts.

    I don't know of any states that specifically put gas taxes (or toll receipts) into a separate account used for road maintenance. If they did, our roads would be paved in gold :-D .

  • common sense

    uhhh? It's built into the cost of operation that there are peak hours and off hours. Many places do use power plants that run during peak hours and shut off for the rest of the day (usually natural gas or diesel generators -- nuclear and coal are much harder to shut down and restart, as you noted)

  • Jess1

    Shhh. Don't you know that "facts" and "reality" are irrelevant to the eventual success of the electric car?

  • epobirs

    When you discover that they seriously want to compare the cost of driving an Expedition to anything substantially smaller, the rest of the article is just a joke. Talk about comparing watermelons to grapes! The guy says he did a thorough analysis of how the electric car would suit his family's needs. This suggests the sole reason he had for driving the SUV was that he liked it but had no practical purpose for its capabilities. (Which is fine if you can afford it.) In terms of reduced operating costs, he could just as easily gotten the same result from a regular gas engine car that was simply smaller. A small ICE car that gets 40-something MPG is also going to consume less fluids and have lower costs beyond fuel.

    They might as well have found somebody who switched from a Peterbilt hauler to a Geo Metro for his daily 20 mile commute. The difference in operating costs would be pretty dramatic and the tax payers wouldn't be called upon to subsidize the Metro.

  • Benjamin Cole

    Common sense: Data clearly show that rural areas are huge--huge--net beneficiaries of federal taxes and spending, contrary to popular conception (at least in right-wing circles and I am mostly a righty).

    The state of North Dakota receives $20k net per capita in federal spending over revenues. You think the oil boom did it all? Wrong. Huge lard state.

    See the Intrepid Data Nerd. This guy is apolitical, and very good.

    http://www.udel.edu/johnmack/data_library/

    Ever wonder why the GOP went to runaway spending when it controlled the House, senate and White House?

    Because they represent pinko-GOP lard states.

    Coyote Blog is great--but is an example of how clouded people are. I hate subsidies for electric cars---but EV's are peanuts next to the dayglo-pink ethanol program.

  • Mike

    While refineries do perform some on-site electrical generation, and may at times put power into the grid, they are still net consumers of grid electricity, in a big way - something this article completely ignores. According to the below link, U.S. refineries consumed nearly 49 billion kwh in 2005.

    http://www.nationmaster.com/graph/ene_ele_con_by_pet_ref-energy-electricity-consumption-petroleum-refineries

  • Evan Dickinson

    Are you sure that producing power in a static factory that doesn't have to widely vary its rate of production of energy like a car and doesn't have to be miniaturized like a cars engine does isn't going to be more efficient?

    What I mean is: is at least converting energy from a power plant and putting it into electrical power going to be more efficient than if a car engine was used for to put energy into electrical power?

    I know that the electrical energy from the power plant must travel and loses more that way.

  • rxc

    The engine in the car also does other things more efficiently than would occur if the energy came from a central power plant, such as heating and AC for the car. And this is important, because you really do want to use your vehicle during the winter when it is very nasty to walk or ride your bicycle, and during the summer, when you don't want to be fried. You also need it when it rains, to defrost the windshield (you need BOTH heat and AC for this function), or you won't be able to see where you are going. The heat in the winter is essentially free - it is waste heat from the transportation. The AC is taken directly off the engine, and doesn't have to deal with transmission, storage, and electric motor losses. Batteries that can propel the car and supply these loads for very long just don't exist.

    Electric cars will never be really useful until they can demostrate that they can travel from DC to NYC in January, during a moderate snowstorm, without refueling, AND do the same trip in August, during a heatwave. This is the sort of trip that people expect to be able to do. If you just focus on short trips around town you will also need a vehicle that is capable of doing thie trip I describe, and will have to double your capital outlay for transportation. It is just like windmills and solar panels that need non-renewable (i.e., continuous dispatchable) backup. They are just too expensive and are impractical, unless we are willing to severely curtail our travel.

    Which, of course, is what the progressives realy want to achieve.

  • Evan Dickinson

    Just using a car for travel too and from work is a very important use and if you can get a lot of fuel efficiency from that a car that gives you that efficiency will be travelling many miles.

    For long distances that is a problem except that eventually we could have battery swap stations so the technology is not in the long-run worthless but could be a model we could run on if we ran out of gas. I'm totally in favor of not pushing things with subsidies, however. Overall we would be much poorer if we had to make a complete switch at this level of technology.

  • marque2

    One of the little known secrets to great mileage in small cars is that they have very small power plants. The Priuses great mileage is just as much if not more - because of the 75hp engine than - because of any of the fancy electric gadgetry. Get rid of all the electronics and I would bet the mileage would be about the same.

    If you want a car that goes 100mpg figure out how to build one around a 40 hp engine.

  • marque2

    It would be interesting to compare the efficiency of cars charged with electricity from Natural Gas and cars that are filled with CNG. It would take the transmission and battery inefficiencies out of the equation.

  • marque2

    Unfortunately for battery technology all the redox equations were published in chemistry books 50 years ago. There really is nothing beyond lithium technology. I have seen some gullible newsreports (ooh the battery that can charge in seconds - doh just a bunch of capacitors, etc)

  • rxc

    Ahhh... someone else who is impressed by lots of zeros. 49 billion kwh is about 1.2 percent of total electricity generated in the US last year (4E12 kwh), assuming that the refineries are using the same amount now as in 2005. Which is probably an overestimate because a LOT of refineries started to co-generate when they were forced to start paying windmill rates for electricity. And, of course, this source does not say whether that is the amount consumed from the grid, or consumed from both the grid and on-site coogeneration.

    You should be careful about relying on your quoted source. I checked it out, and a nuclear statistic popped up that is out of date and therefore amazingly wrong. Lithuania used to be a major nuclear producer, as a percentage of electricity generated, but both units at Ignalina are now closed, so they now produce no nuclear electricity at all. And the heading for the "nuclear generation by country" factoid is quite misleading. It should be "generation as a percent of total generation", not just "nuclear generation". The US is the largest generator of nuclear electricity, in terms of kWh/yr. I wonder if this is a "progressive" web site that is trying to inoculate factoids into the public psyche...