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How far could an EV go on the energy used to produce a gallon of gas?

Discussion in 'Energy, Environment, and Policy' started by omgwtfbyobbq, Aug 22, 2015.

  1. omgwtfbyobbq

    omgwtfbyobbq Member

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    About 10 to 20 miles apparently.

    Shocking : Tesla Model S gets 26.5 mpg

    I think this estimate is pretty good because it takes data from the EPA/ANL for the national average, and State of CA for a regional average. Anyhoo, long story short, we use natural gas, coal, and electricity, that could otherwise be used to create/send electricity to a homeowner with an EV.

    Across the US, this ends up being ~3.5+kWh of electricity equivalent (EE) per gallon of gas. In states where petro extraction/refining is more energy intensive, this ends up closer to ~5.5+kWh/gallon. While not exact, it's far less hand-wavy anything else I've seen and matches up really well with the WTW figures ANL uses in their GREET model.

    The next time someone complains about EVs using electricity, I'll mention that ICEs do too. About 10-20 miles worth depending on the circumstances.
     
  2. spaceballs

    spaceballs Member

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    Btw quick google search on how much kwh you need to make that 1 gallon of gas, looks like 6 kwh used.

    The 6 kWh electricity to refine gasoline would drive an electric car the same distance as a gasser? | The Long Tail Pipe
     
  3. omgwtfbyobbq

    omgwtfbyobbq Member

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    The problem with using refinery efficiency is that the energy lost from a barrel of petroleum during refining isn't available to generate electricity. Natural gas and coal otoh, plus the electricity used directly in extraction/refining, can get electricity to a consumer's home. Darrell's estimate is also a bit high, mostly because it just looks at the amount of gasoline produced, and assumes all the energy inputs go to that, as opposed to be divided among gas/diesel/jet fuel/propane/etc...
     
  4. Ingineer

    Ingineer Electrical Engineer

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    To be accurate you'd also have to account for drilling/extraction as well as distribution pumping/pipeline. It would be hard to generate a real accurate estimate, but you can bet it's a lot of energy. If you've ever seen the huge pipeline running down the middle of Alaska and followed it for hundreds of miles it will definitely leave it's mark on your brain. They have something like 12 pumping stations, though right now only 4 are in use, but they use a huge amount of energy.
     
  5. spaceballs

    spaceballs Member

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    #5 spaceballs, Aug 22, 2015
    Last edited: Aug 23, 2015
    From when I tested my generator to charge my roadster --> Charging from a generator.

    My Honda EU2000i generates 5.7 KWh per gallon, the roadster uses ~0.260 KWh per mile, so ~22mpg.

    I expect power plants that generate electricity to be much more efficient than my generator...

    So I suspect something is off saying "Tesla Model S gets 26.5 mpg".
     
  6. omgwtfbyobbq

    omgwtfbyobbq Member

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    Drilling/extraction are included. You'll need to go back a few posts, but it's all there.
     
  7. kennybobby

    kennybobby Member

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    The energy in 1 gallon of gasoline is 33.7 kWh. The Kiev battery pack is 16 kWh (less than 2 qts) and the 'fuel' gauge has 16 bars (1kWh/bar), so i could only go ~170 miles per gallon.

    rr@85.jpg
     
  8. nwdiver

    nwdiver Active Member

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    So... this comparison is more than a little absurd in both directions;

    - That 6kWh that's often quoted as the energy required to refine a gallon of gasoline is 6kWh energy.... not electricity... those two are not synonymous.

    - No one says, 'My PV array produced 60kWh of electricity today! I saved 12 gallons of gasoline'... trying to say a Model S gets <30mpg is just as absurd...
     
  9. omgwtfbyobbq

    omgwtfbyobbq Member

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    It's not 6kWh of energy, it's 6kWh of equivalent electricity. That ~6kWh/gallon estimate is a bit high as a national average (pretty close for CA), but in terms of the specifics there's ~1kWh of electricity, and ~5-12 kWh of natural gas, which could be used to generate ~2-5 kWh of electricity. There's also a little bit of purchased steam and coal, but the amount used is substantially less than the natural gas/electricity and is generally not included in ballpark estimates.

    Anyhoo... It's not absurd. Someone can say with a high degree of certainty that driving an EV frees up enough energy for electricity generation to move that EV ~10-20 miles down the road (depending on the specifics).
     
  10. nwdiver

    nwdiver Active Member

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    ???? what's the difference??? If I have 6kWh of heat... or oil... or anything not electricity... the most electricity I can get out of that ~6kWh is <3kWh. That 6kWh used to refine oil is typically Natural Gas. You cannot generate 6kWh of electricity from 6kWh of natural gas.
     
  11. spaceballs

    spaceballs Member

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    Saying "Tesla Model S gets 26.5 mpg" simply doesn't make sense, to make sense it would have to be worded "Tesla Model S electricity used in 26.5 miles could have generated 1 gallon of gas".

    In the real word you exchange money for gas, and money for electricity, so around Seattle 1 gallon of gas is $2.80, and that $2.80 buys me 28KWh in electricity. 28KWh (1 gallon equivalent) this let my roadster drive a distance of 107 miles, so it gets 107mpg.

    - - - Updated - - -

    If we take the title literally "How far could an EV go on the energy used in a gallon of gas?"

    1 US gallon = 33.41 kWh/Gal.

    Roadster gets ~0.260 KWh per mile so then it would go 128.5 miles on one gallon.



     
  12. omgwtfbyobbq

    omgwtfbyobbq Member

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    EE is after it's converted to electricity. So for the national average, there's ~6+kWh of ng, and ~1kWh of electricity. After burning the ng in a CC generator, that's ~3+kWh of EE. For a state like CA, that uses more ng, it's closer to ~6kWh EE and ~15+kWh of ng.
     
  13. nwdiver

    nwdiver Active Member

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    Right... that was my point... it takes ~6kWh of energy to convert 1 gallon of gasoline. I suppose you could use 6kWh of electricity but I don't think there's a single refinery in the world that uses electricity to heat oil.
     
  14. omgwtfbyobbq

    omgwtfbyobbq Member

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    Kind of. The ~6kWh figure you're referencing was almost certainly after conversion, since the US average is something like ~8 (probably 9 if you count purchased hydrogen/steam)+kWh (electricity+ng+coal+misc), and for areas where extraction is more energy intensive, it's more like 15+kWh/gallon.

    This translates to ~3+kWh of EE at the US average (only electricity + nat gas converted to electricity, no coal, steam, etc... although those would only add maybe half a kWh), and ~6+kWh of EE in states where more heavy crude is extracted, like CA. The end result is that an EV can go anywhere from ~10-20 miles, depending on where the crude was extracted/refined and what EV is being driven.
     
  15. nwdiver

    nwdiver Active Member

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    So... here are some numbers for 2008;

    ~541M gallons of distillate/day (gasoline/kerosine/diesel)

    ~117GWh of electricity consumed/day

    541M gal / 116GWh = 4.6kWh/gal

    I must say... if those numbers are correct... I'm very surprised... 4.6kWh seems like A LOT; that doesn't include a lot of other items used in the refining process like steam, coal and natural gas....

    Here are some new numbers.... holy crap... ~128GWh per day?!?!?! that's INSANE! I guess I never really looked at this before :redface:

    Am I making a math error? 1GWh = 1M kWhs.... right?
     
  16. TEG

    TEG TMC Moderator

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    And that doesn't take into account the fuel used to distribute the refined fuel from the refinery to the gas station. (Big tanker truck driving long distances.) And to pump the gas from the station into the car. And the amount lost to evaporation, leaks, and, and, ... Using oil as a transportation fuel source is very wasteful.

    Oh, and people will drive out of their way (extra gas used) to get to a gasoline station, whereas a typical EV driver is recharging at home where they were going anyways.

    ----

    The simplistic numbers I hear are like 1 gallon as gas is roughly 30kWH, so a Tesla model S 90kWH pack is like having 3 gallons of gasoline on-board, and so when it gets almost 300 miles range, I think of that as ~100MPG.

    If regular gasoline cars lowered their effective MPG to take into account all the energy used to get the gasoline made and put into them, then they would have much lower MPG numbers. So, I don't think it is right (apples/oranges) to take into account all the generation/distribution beforehand. It is really just about how much energy the vehicle can store, and how many miles it can travel on that energy.
     
  17. stopcrazypp

    stopcrazypp Well-Known Member

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    You flipped the distillate with electricity. It should be 116GWh / 541M gal = 0.214 kWh/gal.

    That would be on par with the estimate I got 4 years ago (0.31 kWh/gal):
    http://www.teslamotorsclub.com/showthread.php/4884-More-anti-ev-gibberish/page15?p=63031&viewfull=1#post63031
     
  18. omgwtfbyobbq

    omgwtfbyobbq Member

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    That sounds right. Refining is ~.3kWh/gallon and nat gas is ~1.5kWh/gallon, which would make ~.7kWh if used in a CC plant, which works out to ~1kWh/gallon EE in refining. Extraction is about double that, w/ total EE being ~3+kWh/gallon. In areas with a lot of heavy crude, it's roughly twice as much EE/gallon.
     
  19. beeeerock

    beeeerock Active Member

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    The oil sands are even worse... far worse:

    http://insideclimatenews.org/news/20130219/oil-sands-mining-tar-sands-alberta-canada-energy-return-on-investment-eroi-natural-gas-in-situ-dilbit-bitumen

    "The average "energy returned on investment," or EROI, for conventional oil is roughly 25:1. In other words, 25 units of oil-based energy are obtained for every one unit of other energy that is invested to extract it.
    But tar sands oil is in a category all its own.
    Tar sands retrieved by surface mining has an EROI of only about 5:1, according to research released Tuesday. Tar sands retrieved from deeper beneath the earth, through steam injection, fares even worse, with a maximum average ratio of just 2.9 to 1. That means one unit of natural gas is needed to create less than three units of oil-based energy."
     
  20. nwdiver

    nwdiver Active Member

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