The (Electric) Energy it Takes to Make (Gas) Energy

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I saw this the other day on Facebook:

…and noticed that Elon Musk made a similar comment:

“You have enough electricity to power all the cars in the country if you stop refining gasoline,” says Musk. “You take an average of 5 kilowatt hours to refine [one gallon of] gasoline, something like the Model S can go 20 miles on 5 kilowatt hours.”

So that’s interesting.  The whole cocktail party retort that electricity has to come from somewhere, and it’s usually from coal, has an interesting twist.  Apparently this new argument came from one Jake Ward –

Jake Ward at DOE:
The energy required to refine a gallon of gasoline can be estimated based on the energy content of crude oil and the refinery efficiency of the facility performing the energy conversion; I can provide you a reputable source for both values.

In a 2008 report, Argonne National Lab estimated that the efficiency for producing gasoline of an “average” U.S. petroleum refinery is between 84% and 88% (Wang, 2008), and Oak Ridge National Lab reports that the net energy content of oil is approximately 132,000 Btu per gallon (Davis, 2009). It is commonly known that a barrel of crude oil generate approximately 45 gallons of refined product (refer to NAS, 2009, Table 3-4 for a publication stating so).

Thus, using an 85% refinery efficiency and the aforementioned conversion factors, it can be estimated that about 21,000 Btu—the equivalent of 6 kWh—of energy are lost per gallon of gasoline refined.
———————————–
The documents referenced herein are publicly available, as follows:
-Wang, M. (2008), “Estimation of Energy Efficiencies of U.S. Petroleum Refineries,” Center for Transportation Research, Argonne National Laboratory, https://greet.es.anl.gov/
-Davis, S., Susan W. Diegel, and Robert G. Boundy (2009), Transportation Energy Data Book, edition 28, National Transportation Research Center, Oak Ridge National Laboratory, cta.ornl.gov/data/
-NAS (2009), Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use, The National Academies Press, www.nap.edu/openbook.php?record_id=12794&page=1

It is worth noting that refining one barrel of oil yields gasoline in addition to other products, so only a portion of the refining energy used to refine a barrel of crude is truly attributable to gasoline. Even so, in terms of energy equivalencies, the preceding estimation is valid.

– Jacob Ward Program Analyst/PMF Vehicle Technologies Program Office of Energy Efficiency and Renewable Energy U.S. Department of Energy

The bottom line – you can use fossil fuels to generate a given amount of power, and that can go to powering an vehicle, or it can go to powering a refinery to refine oil to make gas to power a vehicle. It’s so simple it’s confusing.

I’d love to do an infographic of the energy “costs” from ground to refinery, including the electric use and the costs of that production, all the way out to the pump.  Maybe I will, but not this week.

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One response to “The (Electric) Energy it Takes to Make (Gas) Energy

  1. I wrote a little about this recently, but I agree that it’s worth a longer discussion.
    http://electricmotorcycleforum.com/boards/index.php?topic=3939.msg24252#msg24252

    The gist of the confusion is that most of the energy used to refine gasoline (and other petroleum products) from crude, as well as transport and distribute refining input and output materials, is NOT electricity. These energy inputs could be converted to electricity, but doing so would lose much of the potential energy.

    Additionally, the utility of the other petroleum products is usually discounted in the type of argument Robert is making.

    If all the energy inputs to refine one gallon of gas (and its proportion of additional refining outputs) were converted to electricity, you’d probably end up with a couple of kilowatt hours, enough to drive an electric car 6-10 miles or an electric motorcycle 15-20 miles. So certainly useful energy, but not enough to support the argument that refining energy is enough to be used directly as a gas replacement.

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