Friday, October 7, 2011

It takes a lot of coal to make gasoline


BP Oil refinery in Long Beach California

Quick draw critics of the electric car often (miss their target) criticize EV’s because in their words “Electric cars simply replace a tail pipe with a smokestack” The gist of their argument is that the emissions still occur, not at the tail pipe but at the electric power plant. That great observation is usually followed by the statement that 45% of our grid electricity is coal and coal is dirty thus the EV provides no net gain.

The critics may want to look in the mirror…..or in their garage.

In California, refineries are the second largest users of electricity. Moving water around the state via water authorities is the single largest user of electricity. You guessed it, refining crude also takes a tremendous amount of water!

It is a simple fact that just the refining of gasoline requires approximately 6 kwh of electricity per gallon of gasoline. In fact electricity and natural gas cost are estimated to be 43% of the US oil refineries total expenses. If you tack on the energy required to extract and transport the oil to the refinery and then to the gas stations as well as the energy cost of the gas station, I’m sure that number jumps a few more kwh per gallon.

So let’s be conservative and cut the oil guys a break and say it takes 8kwh to extract, ship, refine and transport each gallon of gas.

What’s good for the goose is good for the gander.  Drum roll…….

It takes more electricity to drive the average gasoline car 100 miles, than it does to drive an electric car 100 miles. A gas car at the US fleet average of 21mpg will consume approximately five gallons of gasoline which took 40kwh (5 times 8)of electricity to make, to drive 100 miles. An electric car will use approximately 30 kwh of electricity (3.3 miles per kwh) to drive the same 100 miles.

In summary,

Gas cars use more electricity than EV’s, thus polluting at the smokestack, They burn that refined gasoline in a very inefficient engine, thus polluting at the tailpipe. In our large urban cities in the US, the emissions caused by our transportation fleet accounts for 70% or greater of our man made emissions and visible particulate matter (smog) and related health care cost. Think of that as smoking two packs of cigs.

Electric cars run on electricity created by a mixture of energy sources. Many electric car drivers like myself quickly discover that making your own via solar PV is the best and cheapest way to fuel (about $0.40 per gallon of gas equivalent) Think of that cleaning up the air in our major cities, saving money and as not smoking,

Cheers

Peder

Mini-E #183, 33,000 solar powered miles

Source material below.

Petroleum Refining:

The United States uses more petroleum than any other energy source. Petroleum provides the U.S. with about 37 percent of the energy we use each year. Petroleum can’t be used as it comes out of the ground. It must be refined before it can be used.

Oil refineries use a lot of energy to convert crude oil into gasoline, diesel fuel, heating oil, chemicals, and other products. Almost half of a refinery’s operating costs (43 percent) is for energy. (US Energy Information Administration)

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 used per gallon of gasoline refined:


The documents referenced are as follows:

US Energy Information Administration

http://205.254.135.24/tools/faqs/

Wang, M. (2008), “Estimation of Energy Efficiencies of U.S. Petroleum Refineries,” Center for Transportation Research, Argonne National Laboratory, www.transportation.anl.gov/modeling_simulation/GREET/pdfs/energy_eff_petroleum_refineries-03-08.pdf

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

19 comments:

  1. Love it Peder! I often use this argument to counter the "long tailpipe" people. Great post!

    I'm about five hours from flying to Munich. I'm scheduled to drive an ActiveE Monday afternoon at 3pm. So when you get up for work in Carlsbad at 7am, I'll be just about getting behind the wheel! I will of course reach out to you when I get back so we can discuss. Anything in particular you want me to do or look into?

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  2. Have a great trip Tom! Enjoy the BMW museum. I am most interested and hopeful to hear that the ActiveE maintains the fun factor and shear enjoyment of driving that the Mini-E has. That’s hard to explain to a non Mini-E driver but you know what I mean  I am also interested in hearing how you like the coasting mid position on the accelerator pedal.
    Lots of pics please!
    Cheers
    Peder

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  3. Peder, this is a gold-mine!

    "It takes more electricity to drive the average gasoline car 100 miles, than it does to drive an electric car 100 miles."

    Can I use you as a source? I'm going to ask Plug In America to exploit this information to the max in future press releases.

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  4. Thank you Cristof and Cooper.

    Many others have touched on this subject including the Tesla forum site. They concluded it about 5.5 to 7 KWH per gallon.

    If you think about the cost, Ifit cost them .05 per KWH and they use 8 its $0.40 cents a gallon. that sounds about right.

    Cheers

    Cheers

    ReplyDelete
  5. This is intersting, and it's good that it's in the open to prompt more accurate / accountable figures to come to light. Also, most of the hydrogen in the world goes into refineries, has anyone done a like for like on Hydrogen cars? Where would the most efficient use of the hydrogen be?

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  6. This is very interesting, but on the EV side don't you also have to include the electricity used to produce the fuel (coal, natural gas, whatever) used to generate the electricity used to charge the car?

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  7. Anon,
    Yes,

    In our case it's Solar and the source is free and does not require energy to trasport. Same could be said wor wind, geothermal and hydro.

    I have aso seen that about 30% of Eelectric car buyers are also buying solar PV.

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  8. the Washington Post just picked up this story.

    http://www.washingtonpost.com/blogs/ezra-klein/post/do-regular-cars-use-more-electricity-than-electric-cars/2011/10/17/gIQAiF67rL_blog.html

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  9. These numbers are misleading. WHere on earth did you get them? "it's a simple fact that" refining a gallon of gasoline takes about 0.4 kWh of electricity. See the US LCI database, maintained by NREL: nrel.gov/lci. Free registration required. Your 6 kwh figure is fiction.

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  10. OK sorry didn't read the source material at the bottom. You're not deceptive, you're just confused. It takes "the equivalent" of 6 kWh of energy to produce a gallon of gas- but the gas contains 35 kwh of energy! For a total investment of 41 kWh (or 39-49 kWh), you get 35 kWh of useful energy.

    In comparison, to produce electricity at the plug-- what you would use to power your EV-- takes about 3 times as much primary energy as what you get. A total of ~100 kWh equivalent of primary energy to get 35 kWh of useful electrical energy. True, he electrical energy is more useful for propulsion-- but in terms of carbon efficiency it's not a clear win at ALL, certainly not in states with a lot of coal power. Coal-fired electricity cannot be more carbon efficient than gasoline unless the carbon is sequestered-- that's just physics [thermodynamics].

    You're interested in the "well-to-tank" efficiencies of gasoline versus electricity- these are very well studied. And the facts don't support your conclusions.

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  11. ...as for coal that's what Saudi Arabia now imports to use steam extraction of their heavy crude (no more light sweet crude there now, already gone). Same for the tar sands in Alberta, needs heated water for extraction. Lots of energy going into the crude now before it even gets to the refinery! May as well just burn the sticky goo in Alberta to make electricity and charge and electric car.

    ...

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  12. This is very exciting, but on the EV area don't you also have to contain the electrical energy used to generate the energy (coal, all-natural gas, whatever) used to generate the electrical energy used to fee the car?

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  16. Sorry, Jake, but we will have to agree to disagree.

    Peder's assertion was about the "average gasoline car." You stated that he shouldn't have used such a generic comparison, but rather only a vehicle roughly comparable to a Leaf. You are entitled to that opinion, of course, but it does NOT render HIS statement "erroneous" or "false": such are indeed the numbers for the "average gasoline car."

    And who is to say what car a consumer would replace with a Leaf? Personally, I would like to see it supplant many of the behemoth SUVs on the road. And well it could for most of those drivers! I opine that Peder's perspective is indeed valid.

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  17. “gas contains 35 kwh of energy"

    This is a common physics rule of thumb trap. There is not a generator on this earth that will give you 35kWh for a gallon of gasoline.
    The reality? 14.5 kWh per gallon.

    http://www.eia.gov/tools/faqs/faq.cfm?id=667&t=6

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  19. You agree then that an EV and a gas car use approximately the same amount of electricity. Total energy for an EV using coal from a 40% efficient power station (30 x 100/40) 75kWh. Total for a gas car (28kWh + 3.2gal x 33kWh/gal = 133kWh.

    ReplyDelete