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How Much Human Energy Is Contained in One Gallon of Gas?

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  • How Much Human Energy Is Contained in One Gallon of Gas?

    from Life after the oil crash

    How Much Human Energy Is Contained in One Gallon of Gas?

    From Dr. David Pimentel:

    "That is, the 38,000 kcal in one gallon of gasoline can be transformed into 8.8 KWh, which is about 3 weeks of human work equivalent.(Human work output in agriculture = 0.1 HP, or 0.074 KW, times 120 hours.)"

    He, of course, is accounting for the energy lost in the process of converting the gasoline into usable energy.

    My calculations excluding the energy lost in the conversion process are as follows:

    1 Gallon of Gas = 125,000 BTUs
    Source: US Department of Energy

    3,400 BTUs = 1 KWH
    Source: US Department of Energy, Bonneville Power Mgt.

    1 Gallon of Gas = 37 KWH
    (125,000 BTUs in a gallon of gas divided by 3,400 BTUs in 1 KWH)

    1 Gallon of Gas = 500 hours of human work output
    (37 KWH in 1 gallon of gas divided by human work output in agriculture of .074 KW = 500)

    Of course, there is some wiggle room with this number. Construction work, for instance, might yield a slightly different number. The size and physical condition of the person performing the work would also make a difference.

  • #2
    How Much Human Energy Is Contained in One Barrel of Oil?

    1 Barrel of Oil = 5,800,000 BTUs
    Source: Louisiana Oil and Gas Association

    1 Gallon of Gas = 125,000 BTUs
    Source: US Department of Energy

    1 Barrel of Oil thus contains the energy contained in 46.4 gallons of gas
    (5,800,000 divided by 125,000 = 46.4 )

    1 Gallon of Gas = 500 hours of human work output
    Source: Calculations Done Above.

    1 Barrel of Oil = 23,200 Hours of Human Work Output
    (Energy equivalent of 46.4 gallons of gas per barrel of oil x 500 hours of human work ouput per gallon of gas = 23,2000 hours)


    • #3
      so, a gallon of gas is still very cheap when you look at it this way.


      • #4
        I stopped reading this when it mentioned David Pimentel. I'm a critic of ethanol, but Pimentel's results stand alone in stark contrast to those of any other unbiased study out there, virtually all of which agree that ethanol is slightly net energy positive.

        Judge for yourself, do you agree with his contentions??

        An interview with David Pimentel | Fill ‘Er Up: On biofuels | Grist

        Pimentel should do a study on aluminum can scavengers. He would conclude they can't possibly make a profit, based on the cost to manufacture their shopping carts and a reasonable labor input of $30 per hour to collect the cans. See how easy it is to skew results??


        • #5
          I appreciate your "acknowledgment" that factual inputs can be so skewed as to render any analysis corrupt and wrong; however, for you to blindly disregard an analysis, simply due to the authors' (in your opinion having skewed data in some prior analysis) could be naive.......

          I can tell you that when looking at the whole picture re: ethanol, i disagree with you. The ONLY way ethanol works is due to Govt (read: US Taxpayers) subsidies and it really does not work then because just as you stated above, the inputs are skewed as the supporters of ethanol completely ignore both Govt subsidies and the fact that the corn that is taken from the food industry (which impacts just about every food product for human consumption to beef production) dramatically raises the costs to the consumer on the other side of the equation - which again the proponents of ethanol disregard.

          Back to the $3.50 gasoline. On this subject, I do consider myself an expert. Being a degreed and practicing Petroleum Engineer, i can tell you first hand that ALL of the low-hanging fruit (Oil Discoveries) have been found and currently either depleted or rapidly depleting. We in the upstream industry have been for years fighting to discover what is left........and judging from the lackluster reserve replacements and production of oil in this country in the last couple of years......when the price of a barrel of oil was more than enough to encourage the expenditures for same.....should tell even the novice that oil is going to become much more expensive - and soon.

          Oil provides the work of hundreds of men......the posts by paddler (and i believe the related post on slavery) by coolreit are central to that theme and proof thereof......

          A simple look at the wealth and living standards enjoyed by developed nations who have learned to harness the power of oil indisputably confirms the value of oil......

          In a time when we have seen triple digit increases in the cost of every material and consumable known to man......except oil......and realizing the relative importance of comes without question in my mind that oil is cheap at $5 per gallon......

          Heck, i bet your wife pays more than $5 per gallon for her shampoo.....


          • #6
            We will have to agree to disagree on empirically proving scientific theory.......we scientists do it ourselves as opposed to relying upon journalistic opinions.......

            I thought the cruxt of the debate was on the $3.50 gasoline?????


            • #7
              Here is another interesting fact about what is in one barrel of oil.