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BMW Created the Most Efficient Electric Car In the US 258

Posted by timothy
from the turning-the-shaft dept.
cartechboy (2660665) writes "You think of efficient electric car and you probably think of the Tesla Model S, right? Well, you'd be wrong as the Model S is only rated at 89 MPGe. As of today, BMW now has the most efficient electric car sold in the U.S., the 2014 i3. The ratings were just posted to the Internet via a window sticker, and at 124 MPGe combined (138 MPGe city, 111 MPGe highway), the i3 is currently king of the efficiency race. The nearest competitor? The 2013 Scion iQ-EV with a 38 mile range and 121 MPGe rating, but it's not even available to the general public. Other competitors are mostly compliance cars such as the Chevrolet Spark EV and Fiat 500e. So where does that leave us? Well, BMW just won the race, for now. But how long until a competitor takes away that top spot?"
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BMW Created the Most Efficient Electric Car In the US

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  • Range is the issue (Score:5, Informative)

    by stewsters (1406737) on Thursday May 01, 2014 @05:42PM (#46894151)
    Most of the power is going to hauling a battery around.

    Tesla s has 265 mile range
    i3 has 81 mile range
    Scion iQ-EV has 38 mile range

    I would be curious to see how the numbers hold up if they all were designed for the same range.
  • by netsavior (627338) on Thursday May 01, 2014 @06:02PM (#46894389)
    the EPA defines a gallon of gasoline as equivalent to 33.7 kWh.

    This is based not really on chemistry or scientific properties of either, but on the cost of gasoline at the pump vs the cost of electricity at your house. http://www.fueleconomy.gov/feg... [fueleconomy.gov]

    Basically it is done this way to make it easy to do the math in your head "hey, this costs 1/3 as much to fuel than my current car"
  • by Anonymous Coward on Thursday May 01, 2014 @06:04PM (#46894415)

    MPGe is an estimate based on a usage protocol developed by the Gov't. It is good for comparison purposes but it does not really work well in the real world. For example the Tesla S when purchased includes lifetime free charging on Tesla's own superchargers which are using solar power for the most part. That sort of support is beyond the pale of the typical auto manufacturer. But some Tesla's don't use the superchargers so their MPGe may be closer to what the EPA says. As the saying goes, YMMV!

    When you get an EV or plugin hybrid you find the calculations to measure your vehicle performance are complicated.

  • Re:MPGe (Score:4, Informative)

    by Ralph Wiggam (22354) on Thursday May 01, 2014 @06:06PM (#46894435) Homepage

    For the last year, I have driven a Nissan Leaf with an 80-90 mile range. On only two occasions I was not able to make a trip I wanted to make because of my car's range. Manufacturers are clustering around that range number because it's good enough for most people a vast majority of the time.

  • by fnj (64210) on Thursday May 01, 2014 @06:08PM (#46894457)

    Efficiency doesn't matter for an electric car that can be powered for FREE by the sun

    Completely naive fail. Apparatus to convert that sunlight to electric power costs money and has to be depreciated. Not only is photovoltaic power not free; its cost [wikipedia.org] ($130 / MWh) is higher than natural gas ($64 to $128 / MWh), coal ($96 / MWh) or advanced nuclear ($96 / MWh). Those estimates for systems coming on line in 2019, so they are not based on obsolete data. Solar thermal is even worse ($243 / nMWh).

  • by Noah Haders (3621429) on Thursday May 01, 2014 @06:11PM (#46894489)
    The exact opposite of true. It's just a measure of energy. 33.7 kWh is about 120mj, which is the same as a gallon if gas.
  • Re:Chevy Spark EV (Score:4, Informative)

    by damnbunni (1215350) on Thursday May 01, 2014 @06:16PM (#46894549) Journal

    The Spark is only sold in California and Oregon, according to GM's official page on it.

    Oregon's ZEV/LEV legislation is based on California's.

    Looks like a compliance car to me!

  • by mlts (1038732) on Thursday May 01, 2014 @06:24PM (#46894631)

    MPGe is like MPG... It is cool for advertising, but in the real world... doesn't mean that much. What really counts is both gpm (or l/km) or even more generally, cost per unit distance. For example, new diesel vehicles are touted as great for mileage. However, if one factors in the repair costs, and the need to use DEF as a second fuel, the gap can close between a TDI vehicle versus a hybrid or even a plain old gasser.

    This can vary for a person. For example, one cow-orker I work with lives fairly close. So, the relatively small range of a Leaf is good enough, since he never really taxes it. However, if the EV was an only vehicle, it might be that the greater CPM of a gasser might be a better fit.

  • by jamesl (106902) on Thursday May 01, 2014 @06:30PM (#46894683)

    German auto brand Volkswagen's XL1, which it claims is the most fuel-efficient production car ever made, has been named the winner of the Transport category at Designs of the Year 2014.
    http://www.dezeen.com/2014/05/... [dezeen.com]

    You may have seen this advert in the Goodwood Festival of Speed programme and are wondering how we determined that the XL1 was the worldâ(TM)s most fuel-efficient hybrid production vehicle.
    http://www.volkswagen.co.uk/ab... [volkswagen.co.uk]

    And it's a looker.

  • by timeOday (582209) on Thursday May 01, 2014 @07:17PM (#46895035)
    The Tesla is a much larger car all around, not just the battery.

    A better comparison to the BMW i3 might be the Fiat 500e [fiatusa.com] (sold only in California). It's even a bit smaller than the BMW, and gets "only" 122/108 MPGe vs the 138/111 for the BMW. So, I do find the BMW impressive. However the Fiat starts at $32K which almost $10K less than the BMW. Making a car light without other sacrifices does require more expensive materials, so I would expect more from the BMW than the Fiat, and evidently it delivers.

  • More importantly... (Score:5, Informative)

    by timeOday (582209) on Thursday May 01, 2014 @07:45PM (#46895311)
    The BMW didn't win by chance, but because it is based on a totally different construction method [cars.com] to makes it lighter:

    What makes the i3 different from every other car on the market is under the skin - it's almost entirely made out of plastic. This is no ordinary plastic, mind you - it's carbon-fiber-reinforced plastic. It's basically the same stuff used to make Formula One cars and stealth bombers. What's remarkable about the i3 is that it's the first mass-market car made out of carbon fiber. There's no metal in the car's body - all the bumpers, doors and skins are plastic as well. The only major metal parts are the drive unit and suspension components. The result is a four-seat, four-door city car that weighs only about 2,700 pounds - or nearly 500 pounds less than a BMW 1 Series.

    This actually quite a bold and innovative new product. It's a shame they made it so ugly. I'm really curious to see crash test results.

  • by Macman408 (1308925) on Thursday May 01, 2014 @08:02PM (#46895451)

    Most of the power is going to hauling a battery around.

    That's a bit of an exaggeration/misinterpretation. Yes, the battery can be heavy; on a car with a reasonably long range like the Tesla, about a quarter of the weight (1,000-1,300 pounds) is the battery. On the other hand, some of that weight gain is offset by removing things that aren't needed - like the gas tank, fuel pump and hoses, gasoline itself (about 120 pounds for a full 20-gallon tank), as well as other components that aren't needed on an EV. As another example, a V8 engine weighs around 600 pounds; the Tesla Model S motor apparently weighs about 150 pounds - or 300 pounds if you include the reduction gear and inverter.

    Anyway, the reason why range is difficult is that the energy density of gasoline is far higher than that of a battery. An 85 kWh battery, at ~1,300 pounds, has an energy density of 0.24 MJ per pound. Gasoline, on the other hand, contains about 19.2 MJ per pound. Even at the abysmal efficiency of an internal combustion engine (on average, about 20%), they still need 16 times less weight in fuel than an EV does in batteries.

    The car companies are solving for a complex set of variables - the volume of the car dedicated to batteries, the weight (and thus power-to-weight ratio), the cost, the range requirements of their target market, etc. Tesla is trying to make the EV people's primary car, by using a huge battery capable of brief ultra-high-power recharging; most other companies have chosen to simplify, by marketing the EV as a family's second car - good for going to work, school, and errands (and 99% of most peoples' driving); but they still have a second car for road trips.

  • by Anonymous Coward on Thursday May 01, 2014 @09:47PM (#46896105)

    Efficiency doesn't matter for an electric car that can be powered for FREE by the sun

    Completely naive fail. Apparatus to convert that sunlight to electric power costs money and has to be depreciated. Not only is photovoltaic power not free; its cost [wikipedia.org] ($130 / MWh) is higher than natural gas ($64 to $128 / MWh), coal ($96 / MWh) or advanced nuclear ($96 / MWh). Those estimates for systems coming on line in 2019, so they are not based on obsolete data. Solar thermal is even worse ($243 / nMWh).

    About $70/MWh in Texas. Just under $50/MWh aka 5 cents/kWh after the federal subsidy.

    http://www.greentechmedia.com/articles/read/Cheapest-Solar-Ever-Austin-Energy-Buys-PV-From-SunEdison-at-5-Cents-Per-Ki

    Prices have dropped rapidly so you really need to check quarterly and not use any source even slightly outdated. That EIA report uses 3 year old data, and further monkeys with the cost of money in weird ways costing "green" ones at 3.5% and fossil 6.5% - for no reason at all other than a hit job on fossil prices. It also uses $8/mmBTU price for natural gas without saying it, so overcosts natural gas. Kind of a load of crap.

    http://www.eia.gov/forecasts/aeo/electricity_generation.cfm

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