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OT: Energy=Horsepower-Hours ???

Discussion in 'Electronic Design' started by John Popelish, Apr 10, 2007.

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  1. If you add in all the fuel used plant, fertilize, harvest
    and process the grain used to make ethanol, it is clearly
    more energy wasteful and carbon emissive to use ethanol as
    fuel than it is to just use the fossil fuel, directly.

    Someday, when the technology is available to make high grade
    ethanol from wood waste and grasses that grow without much
    assistance, that may change.
  2. Jim Thompson

    Jim Thompson Guest

    Anyone have effective energy numbers for gasoline and ethanol in units
    of horsepower-hours?

    Likewise equivalent pounds of CO2 and H2O output?


    ...Jim Thompson
  3. Joerg

    Joerg Guest

    Maybe this helps:

    Has conversion factors in there as well. Horses are a bit unusual here
    so I guess you'd have to go from BTU to kWh and then horses per hour.

    Probably the DOE has that info, somewhere. Probably needs a bit of googling.
  4. Jim Thompson

    Jim Thompson Guest

    I just realized that I, myself, have been succumbing to the greenie
    bullshit... ethanol IS a hydrocarbon ;-)

    My bet is, when normalized to unit energy, they're equivalent
    greenhouse gas polluters.

    ...Jim Thompson
  5. How many gallons of fossil fuel does it take to grow and
    process that slightly more than 1 gallon of ethanol (that
    contains the same energy as a gallon of fossil fuel)?

    Right now, it is considerably more than 1. Of course, you
    could use ethanol instead, for those steps, but that only
    increases the fossil need more.

    It is like losing money on each item sold, but making up the
    loss with high volume.
  6. Jim Thompson

    Jim Thompson Guest

    Everyone kids "W" about his references to prairie grass, but I think
    that's where it'll be.

    Ever struck a match to tumbleweed ?:)

    You'd think you just threw gasoline on a fire.

    ...Jim Thompson
  7. Joerg

    Joerg Guest

    Yeah, I guess. It's just that oil comes out of the ground and generates
    "new" CO2 while planted stuff consumes CO2 during growth and then
    releases it again. Of course that doesn't take into account other
    nasties such as fertilizer usage.

    It's like our wood stove versus other people's gas heaters. Wood burning
    is CO2 neutral while gas isn't.
  8. (snip)

    The octane rating is not meant to measure the energy content
    of fuel. It is a measure of the knock (pre-ignition)
    resistance of the fuel. If you don't have a pre-ignition
    problem to solve, higher octane fuel is all cost (including
    higher exhaust pollution and worse engine grime) and no
    benefit for you.
  9. Joerg

    Joerg Guest

    Yep, sounds like hydrogen which, at the present stage of how to go about
    it, is IMHO not the solution to our oil dependence.
  10. Oppie

    Oppie Guest

    One of my rants has been with the Bureau of Weights and Measures that
    seals all the scales and gas pumps to ensure accurate delivery. There is an
    Octane rating but that does not really equate to the energy content in a
    gallon of fuel.
    I care less about the quantity of the fuel than the BTU per gallon. With
    lots of distributors now adding alcohol to gasoline, the miles per gallon is
    decreasing and cost keeps increasing.
  11. Guest

    You can find out this information easily enough on the web, or in a
    decent technical library

    My pocket scientific data books lists enthalpies of combustion for
    ethanol - 1371 kilojoule per mole - and for n-octane - 5512 kilojoule
    per mole. You need to know the molecular weight of ethanol - 46.07 -
    and of n-octane -114.23 - before you can do anything useful with these
    numbers, as a mole of ethanol is 46.07 grams of ethanol, and a mole of
    n-octane is 114.23 grams.

    If you really do want to convert joules in to horse-power hours, you
    will also need to know that one horsepower is 745.7 watts (or joules
    per second) and that an hour contains 3600 seconds.
    The molecular weight of CO2 is 44.01 and of H2O is 18.016, and there
    are 454 grams to the pound.

    Jim either didn't do high school chemistry or has forgotten all he was
  12. Guest

    The technology is already available. Most Swedish schnapps is made by
    fermenting paper mill waste - which is to say the degraded cellulose -
    which is a polmer of glucose - that didn't end up in the paper being
    made at the paper mill.

    Termites have commensural bacteria in their stomachs which degrades
    cellulose to digestible sugars, if you don't want to use a paper mill
    to do the job.
  13. Guest

    Ethanol is C2H6O - two carbon, six hydrogen and one oxygen. That
    single oxygen molecule means that it isn't a hydrocarbon, but an
    As has been pointed out by Joerg, ethanol is produced from green
    plants, which absorb their carbon from atmospheric CO2, making ethanol

    Furthermore, it contains a lttle more hydrogen than regular
    hydrocarbons fuels - octane is C8H18 - so a bit more of the energy you
    get from burning ethanol comes from turning hydrogen into water, which
    isn't a greenhouse gas.
  14. On 10 Apr 2007 14:56:54 -0700, in
    Nah, he needs to eat more greens and stuff, like Mr Kellogg suggested

  15. Jim Thompson

    Jim Thompson Guest

    I wouldn't bet on the "accurate delivery". I've been keeping a
    spreadsheet on the new car and discovered that mileage was low about
    5% from a certain store... could be junk gas of course, but I suspect
    more likely a "tweaked" pump.

    ...Jim Thompson
  16. There is also some good research and development of high
    efficiency catalysts that de-polymerized cellulose into
    fermentable glucose. But these or the methods you describe
    are not yet in significant use in the production of fuel
    ethanol in the U.S. They are still using food grade crops,
    grown, fertilized and harvested, using lots of fossil fuel
    to make a lower grade fuel that is only salable with large
    government subsidies. These subsidies are not so much
    helping the future methods to be developed as they are
    restraining their development, because big money is being
    made without them.
  17. The internal combustion I am looking forward to operating is
    a variable displacement, variable compression ratio design
    that has no carburetors or throttle body, but just intake
    ports with fuel injectors. It adjusts its displacement and
    stroke to compress the fuel air mixture to just below that
    which causes pre-ignition while producing only the horse
    power required, from idle to full, high speed acceleration.
    It can also adjust to run on any vaporizable fuel of any
    octane rating, from hydrogen to ethanol to 98 octane jet
    fuel, obtaining the maximum practical mechanical energy from it.

    Experimental (and impractically heavy) hydraulically
    adjusted versions are being tested in dynamometer, and the
    test results, so far, indicate that a typical vehicle with a
    given peak horsepower capability would use about half the
    fuel, on average, compared to a fixed displacement and
    compression ratio engine in use, today.

    How would you like to have a vehicle that goes something
    like 50 miles on a gallon of low grade gasoline with 200 HP
    available, or 55 on premium with 220 HP available?
  18. Detailed comparisons at

    A more reasonable unit of measurement is the watthour per liter.

    Ethanol, of course, is utterly worthless in that it is simply diesel
    fuel in disguise when grown as corn under US farm conditions.

    You have basically a big funnel. You pour lots of diesel fuel in the
    top, and a little ethanol dribbles out the bottom.

    Ethanol is pretty much an outrgeous twelve billion dollar federal vote
    buying scam.

    Ethanol from switchgrass or bagasse MAY EVENTUALLY have some net energy

    Many thanks,

    Don Lancaster voice phone: (928)428-4073
    Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
    rss: email:

    Please visit my GURU's LAIR web site at
  19. I'm always surprised to see the low efficiency wood stoves
    (creosote manufacturing machines) in use almost everywhere.
    We, as a species have been using fire long enough to do it
    better than most wood stoves do it. So many people seem
    proud of how primitive their wood burners are.
  20. I don't have a study handy, but I have read some. Have you
    thought about how many times you have to drive a tractor
    (that has not been made to be particularly energy efficient)
    up and down the rows to spray herbicide (and manufacture
    that) or plow, plant, fertilize (and manufacture and deliver
    that), harvest corn, then deliver it to an ethanol plant,
    convert the corn to ethanol, deliver that to fuel mixing and
    storage stations, deliver the fuel to consumers?

    I'm not saying that there are no fuel costs in drilling,
    pumping, delivering, fractionating, delivering to storage
    facilities and delivering fossil fuel to consumers, but that
    farming adds a a very energy intensive branch to the total
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