FEEDING OUR OIL HABIT: HARD CHOICES

February 10, 2013 § 9 Comments

The Keystone XL pipeline hangs in the balance on the President’s desk.  Opposition to it is the cause du jour of the Sierra Club and certain celebrities.  The Sundance Kid has an op ed in a recent Huff Post railing against the “dirty oil” from Canada.  So, how dirty is Canadian oil and what are the alternatives?  I think we all recognize the reality that displacement of oil based fuel is going to be incremental.  So we are going to have to make choices regarding the sources of our oil.

keystone xl route

The top four sources for our foreign oil are Canada, Venezuela, Saudi Arabia and Mexico.  Most of the oil from all but Saudi Arabia is classified as heavy oil.  Even Saudi oil is starting to get heavier.  The term heavy is used for the fact that the oil has a greater proportion of large molecules.  As the molecule gets larger, the relative proportion of carbon by weight compared to hydrogen is higher.  When such oil is refined, the long chains are broken down thermally and hydrogen added.  This process is known as hydrothermal cracking.  For particularly heavy oil a carbonaceous residue is left known as petroleum coke.

The charge of “dirty oil” leveled against Canadian oil is based primarily upon the fact that the petroleum coke, if utilized, releases carbon dioxide.  Clearly a processed light oil such as the shale oil from the Bakken or Eagle Ford has very little of this residue and so is clean in comparison.  But petroleum coke is in fact quite comparable to coal.  The energy content is generally a good deal higher than most grades of coal and the ash content is much lower.  But it usually is worse on sulfur content.  For workhorse applications such as cement kilns that is of little consequence because of the presence of agents that capture the sulfur.  Petroleum coke also has significant quantities of heavy metals nickel and vanadium.  This almost all ends up in the ash in a form that is essentially not leachable by water.  Nevertheless, this too is another reason for the “dirty” appellation.

In the event of a spill heavy oil biodegrades more slowly.  This is in part because oil eating bacteria prefer the smaller morsels of the light constituents.  On the other hand it will not leach into the soil as readily because of the viscosity.  This notwithstanding, the originally proposed route for the Keystone XL was ill conceived.  It went through a portion of Nebraska where the sediment was very porous, and this overlaid the Ogallala, the most important aquifer of the region.  The proposed new route is longer (see red portion on map), but avoids the potential for aquifer contamination.

A little discussed fact is that the pipeline will also carry some of the light oil from the Bakken shale oil fields in North Dakota and possibly Montana.  This important new source of light oil is currently being transported by truck and rail, increasingly the latter.  Both of these forms, especially trucks in the northern climates, would appear to be more spill prone than pipelines.  Besides, absent a pipeline the Bakken oil will likely be limited in production, which is not good news for domestic output.

Consider the scenario of the Keystone XL not being permitted.  The Gulf Coast refineries have expensive equipment known as cokers, specially designed to handle heavy oil.  If Canadian oil is curtailed they will source heavy oil elsewhere.  The best bet is Venezuela, already a source.  The carbon loading of this oil is very similar to that from Canada.  Furthermore, the nickel and vanadium concentrations are three to four times greater.  Trading Canadian partnership for dependency on a country with leadership unfriendly to US interests sure sounds addled.

Finally, consider the question: can Canadian crude be cleaned up before it comes to us?  The answer is yes.  The simplest way to accomplish this is to remove much of the excess carbon prior to shipping using a technique known as de-asphalting.  When propane, hexane or a combination are added to heavy oil, they pick up the lighter component of the crude and the carbon heavy asphaltene drops out as a solid.  The extracting liquid can be regenerated for re-use and the so called de-asphalted oil (DAO) can be sent down to us.  A bonus: much of the sulfur and most of the heavy metals preferentially segregate to the asphaltene, so the DAO is lower in these elements as well.

Our refiners currently get Canadian crude at a heavy discount.  The DAO will likely command a better price.  The cokers will be underutilized because the oil is cleaner.  But the country will be the better for it.

Vikram Rao

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§ 9 Responses to FEEDING OUR OIL HABIT: HARD CHOICES

  • Steve Townsend says:

    This is a great article, Vic. Thanks. Keep up the good work.

  • I agree with Steve’s comment! I really appreciate your knowledge and ability to explain this complex subject. However, I am still opposed to the pipeline primarily because of the signal it sends regarding our nations continued reliance on dirty fossil fuels and the damper this puts on alternatives.

  • Pete Andrews says:

    Vik, one of your most informative blogs. Thanks.

  • Mark Corigliano says:

    Another reason for the “dirty” label on Canadian tar sands involves the carbon-intensive process for extracting the oil. In steam-assisted gravity drainage (SAGD) systems, natural gas is burned to create steam that is pumped into the ground, improving flow rates. In mining operations, even more fuel is burned in the extraction processes.
    The administration is essentially enacting a carbon tax by not approving the Keystone XL pipeline. Therefore, everyone would be better served with a carbon tax (or cap and trade system) and let the market sort out the details. Enough of the government picking winners and losers.

    • rtecrtp says:

      Mark is correct regarding the extra carbon burden on the extraction process. I did not get into it in part because that was a Canadian matter and in principle ought not to enter into the President’s decision.

      Adopting a North America stance, I will comment on a couple of things happening and that could happen. Innovations such as producing the steam downhole significantly improve steam efficiency especially in winter. The mega target would be to in-situ reduce the size of the molecules before lifting. This is not wishful thinking. Research is under way in Canada and Norway. But it is going to be difficult.

      Vikram Rao

  • John Cambier says:

    Vic,

    It is my understanding that one main reasons the oil from Canada is referred to as “dirty” is not related to it being heavy vs. light crude, but rather the methods undertaken to mine the oil and disaggregate it from the sand in which it is trapped. In addition to damaging/destroying vast swaths of land at the surface, the amount of water used and polluted are immense, are they not?

    Though Venezuela is a less-than-ideal trading partner, I’m not sure I would characterize Mexico as any less attractive a neighbor and ally than Canada. Saudi Arabian oil is admittedly fraught with external costs, but mass degradation of the environment is not among them.

    To say that the oil from the oil sands of Canada is, at most, no worse than coal from a conversion and pollution perspective is damming with faint praise. I know that we will need time to transition away from our liquid fuel dependency on oil, but making sources such as Canada’s oil sands more readily accessible and refineable runs the very-real risk of lessening the urgency we have to make the moves necessary.

    • rtecrtp says:

      True that mining creates a huge body of waste water known as tailings ponds (lakes, really). But I see very lttle of new activity going to mining, mostly to SAGD. Also, as far as I am aware, most mined oil is “upgraded” on site to a light oil known as Syncrude, which is similar to WTI in character and price. The dirty oil if you will does not come down here.
      I did not mean to juxtapose Canada and Mexico, just Venezuela. Besides, Mexican oil does not have as much heavy metal as that from Venezuela.
      To your last point, displacing oil sourced products should be done the old fashioned way: make the alternative cheaper and/or more effective. See my posts on use of methanol in gasoline.

      Vikram Rao

  • From my understanding, the eroi (energy returned on energy invested) of tar sands oil is only around 7 barrels to one and drops even further when processed into usable forms (I’ve read that it drops to between 3-5 to 1).

    I also found one problem in this analysis in that these EROI studies gave quite a bit of credit for electricity that was co-generated with the steam used in the recovery process. While there is no doubt that electricity is delivered to the local grids, a lot of this electricity that was delivered resulted in excess supply that was/is never utilized.

    So, by the time you consider the environmental damage that mining tar sands creates, the fact that the energy payback is low, the large amount of water that is used, the failure rate of pipelines and the HUGE potential environmental damage that could result when there is a leak, and, as was pointed out in the previous comments, the fact that this supply of oil will slow the transition to clean forms of energy, my belief is that this oil should simply be left in the ground!

    Two other considerations that I would like folks to consider is that most of the EROI numbers, as well as pipeline failure rates are produced by parties that have a stake in the production and transportation of this oil.

    Having lived in Wood River, Illinois (where some of this oil would be transported and is home to numerous oil pipelines), I can tell you that oil pipelines leak! They are also not very well secured or protected and therefore could present a easy to attack target that could result in catastrophic consequences!

    Bob “The Clean Energy Guy” Mitchell

  • Mark Corigliano says:

    All forms of energy production and consumption create environmental impact to air and water. Currently, these are “free” resources that are overly exploited. Clearly, air and water are precious and those responsible for damaging our environment (all of us) must pay to do so. If we had a carbon tax, we would not need this debate because the question would be settled by the financial decisions of private enterprise.

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