Flying brick

Beware the hype around plug-in hybrids 6

An article in Business Week Online tells us that experimental hybrid cars get up to 250 mpg (a very similar article appeared in the New York Times business section a couple of months earlier). I enjoy reading between the lines of lay press science and technology articles. There was a great discussion in Grist on this subject not too long ago.

Gremban ...spent... $3,000 tinkering with his car... [I]n the trunk sits an 80-miles-per-gallon secret -- a stack of 18 brick-sized batteries... [T]he extra batteries let Gremban drive for 20 miles with a 50-50 mix of gas and electricity.

In other words, for his $3000 he will get 80 miles per gallon for 20 miles before his carriage turns back into a pumpkin. For the rest of the day he will carry a hundred pounds of bricks around in his now-useless trunk, which by the way will degrade his gas mileage. For the first 20 miles he drives each day he will save 0.25 gallons, thus recouping his $3000 in about twenty years, assuming his batteries last that long. The more miles he drives after the batteries go dead, the worse things get because of the extra weight of the dead batteries in his trunk. Which leads me to ask: If his commute is only ten miles each way, why not just ride a bike, get a little exercise, and save $3000? You can also get 80 mpg out of a 40-mpg car by carpooling with one passenger, or get 120 mpg with two passengers, or 160-mpg with three passengers.

Monrovia-based Energy CS has converted two Priuses to get up to 230 mpg by using powerful lithium ion batteries. It is forming a new company, EDrive Systems, that will convert hybrids to plug-ins for about $12,000

In other words, you will get up to 230 mpg (the equivalent amount of oil burned by the power plant to charge you up) before the batteries that are powering the car go dead. Oddly enough, they forgot to mention how many miles you could go before that happened. You will then turn back into a hybrid and lug $12,000 worth of discharged lithium-ion batteries around with you all day until you can get to an outlet for five or six hours.

University of California, Davis engineering professor Andy Frank built a plug-in hybrid from the ground up in 1972 and has since built seven others, one of which gets up to 250 mpg. They were converted from non-hybrids, including a Ford Taurus and Chevrolet Suburban. Frank has spent $150,000 to $250,000 in research costs on each car, but believes automakers could mass-produce them by adding just $6,000 to each vehicle's price tag.

In other words, after having spent millions of somebody's dollars dinking around, he believes it would only cost an extra $6000 to mass-produce plug-in hybrids that presumably have similar performance to the ones mentioned above. So take your pick. Will it cost an extra $3000, $6000, or $12,000 to save between 65 cents to a dollar a day on gas, depending?

20 miles/40mpg=0.5 gallons, 0.5 gallons x $2.5 = $1.25.
20 miles/80mpg=0.25 gallons, 0.25 gallons x $2.5 = $0.625
$1.25-$0.625=$0.625

20 miles/240mpg=0.083 gallons, 0.083 gallons x $2.5 = $0.21
$1.25-$0.21=$1.04

After all of this you might assume I am against plug-in cars. Actually, I'm not. I think they have great potential. You just can't have your cake and eat it too. They will cost more. The Prius is popular for five main reasons: It has reasonable performance, gets great gas mileage, is aesthetically appealing, of excellent quality, and reasonably priced.

Screw up any of those parameters (add six thousand dollars to its price) and watch what happens to its popularity. If enough people want plug-ins bad enough (are willing to pay for them) they will get them.

My real name is Russ Finley. I live in Seattle, married with children. Suffice it to say that although I am trained and educated as an engineer, my passion is nature. I very much want my grandchildren to live on a planet where lions, tigers, and bears have not joined the long and growing list of creatures that used to be. In an attempt to minimize the workload on Grist editors responsible for turning my submissions into intelligible articles, I will also be posting on a seperate blog called Biodiversivist, which will contain articles in addition to those submitted to Grist.

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  1. Jamais Cascio Posted 10:10 am
    14 Aug 2005

    Bear in mind......that with some of the plug-in hybrid designs, the extra batteries are not "dead weight" once discharged, but still function as standard hybrid batteries -- that is to say, will still be recharged through regenerative braking, coasting, engine transfer, etc.. At least with the GO-HEV Prius conversions, the car's computer is tricked into operating in electric-only mode for far longer than normal, but otherwise operates as a standard hybrid, albeit with far greater battery storage.
    Plug-ins will cost more, no doubt, but the economics may not be quite as bad as you suggest.
    (And, as a resident of the SF Bay Area, I see your $2.50 number for a gallon of gasoline and just shake my head...)
  2. odograph Posted 10:47 am
    14 Aug 2005

    prioritiesThe $3000 mod is the cheapest I've seen ... but I still think the priority should be on getting more people into the stock Insight/Prius/Civic hybrids.
    Those cars cost less than the average selling price for a new car in America (approx. $26K).  They are inexpensive.  They get great mileage.  They don't require an additional $3-10K battery investment, they just work.
    Given that a plug-in requires X times the number of stock batteries, you could build X times the number of stock hybrids with the same battery supply.
    The stock hybrid a much safer bet.
  3. MikeCapone Posted 10:48 am
    14 Aug 2005

    BatteriesExactly, the added batteries are not dead weight if they are added to the main batteries, it's just that their "plug-in" benefits are limited to the first miles.
    But with better, non-DIY batteries, it would probably be pretty easy to reduce price and augment the plug-in range.
    And what if you drive only ~20 miles per day on average?
    As for the monetary payback on the batteries: People don't buy cars to save money. They don't pay for mooroofs and bigger engines and mag tires to save money. Why should extra batteries save money? These batteries are there to save oil and reduce pollution. Otherwise, I doubt that he'd have invested in them.

    --


    SUVs are squared-out minivans.
  4. odograph Posted 11:02 am
    14 Aug 2005

    ROIAs far as payback, the botttom line for the world is total oil burned and then total CO2 produced.  You can look at that per capita.  You can look at your personal weekly gasoline bill, and calculate your weekly gasoline-derived CO2 release.
    I've got a feeling that these guys are doing something interesting to them ... but I doubt they are making the most cost-effective energy or CO2 reducing investments.
    What if you drive a prius and plant $3-10K worth of trees?  What if you skip the prius, buy an echo and plant $13-20K worth of trees?
    What if you spend $1k and ride a really nice bike?
  5. Biodiversivist's avatar

    Biodiversivist Posted 11:16 am
    14 Aug 2005

    Good points JamaisI am no expert on hybrid car design. I can't take credit for the bad economics, they came from the quoted article. I'm with you though. I can't see the difference in price being more than two or three grand once they get into mass production.
    I pulled the $2.5 out of the air. Plug-ins get more and more feasible with rising gas prices.

    In the end, it all comes down to biodiversity. Help acquire and protect ecological hotspots, give to a conservation organization: http://www.saveourbiodiversity.com
  6. ben Posted 1:07 pm
    14 Aug 2005

    Effect on oil importsIncreasing fuel efficiencies will go a long way to reducing oil imports. It's strange to think that there was nothing put into the energy bill addressing this.
    If all cars went from the current 20mpg to 80mpg (4 times efficiency increase), then the US would reduce oil consumption by 27%. If all US transportation increased fuel efficiency by 4 times, then the US would reduce oil consumption by 45%.

    theWatt.com

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