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Gauging The Carbon Cost Of Fuel From Canadian Oil Sands

Environment: New study finds that greenhouse gas emissions associated with fuel from Alberta oil sands are about 20% greater than those for U.S. crude oil

by Deirdre Lockwood
June 22, 2015

Credit: Shutterstock
Producing and burning fuel from Alberta oil sands creates about 20% more greenhouse gases than producing and burning fuel from U.S. conventional crude oil.

The oil sands of Canada’s Alberta province are one of the world’s largest oil reserves, currently producing the equivalent of 2 million barrels of crude oil per day. But it takes lots of energy to transform the heavy bitumen in the deposits, which is bound up with sand and clay, into diesel and gasoline. A new study presents a comprehensive analysis of the greenhouse gas emissions associated with fuels from the oil sands—from extracting to shipping to refining to burning—and concludes that emissions are about 20% greater than those from fuels produced from conventionally extracted crude oil in the U.S. (Environ. Sci. Technol. 2015, DOI: 10.1021/acs.est.5b01255).

Currently, only about 9% of crude oil processed by refineries in the U.S. comes from the Canadian oil sands, but analysts project that this share will grow in the future, especially if long-distance pipeline projects such as Keystone XL go forward. Researchers want to understand the carbon footprint of these fuels to help assess their impact on climate, and to track progress toward emission reduction targets. So Hao Cai of Argonne National Laboratory and his colleagues set out to determine the greenhouse gas emissions associated with all the steps involved in production and use of oil sands products refined in the U.S., often called a “well to wheels” life-cycle assessment.

Previous assessments have suffered from limited, proprietary data or were based on less energy-efficient oil production processes than those used today. In the new study, the researchers used publicly available monthly operations data from 27 oil sands projects between 2008 and 2012 and assessed emissions using a model developed at Argonne. The operations data allow the model to estimate emissions resulting from powering the machinery needed to extract oil from the sands, heating steam used in the process, and even from bacteria giving off carbon dioxide and methane in wastewater ponds.

The journey from well to wheels begins with extraction. In surface mining, oil companies use trucks to dig up shallow sands, rinse them with hot water, and shake the mixture to separate out the bitumen. For deeper deposits, they drill wells and inject steam to separate the bitumen from the sands, and then pump it out—a method called in situ recovery. Once the heavy bitumen is recovered, it is diluted with lighter hydrocarbons so it can be more easily transported to a refinery or partially refined on-site into a mixture called synthetic crude.

With the model, the researchers considered four different production scenarios—using either surface mining or in situ recovery for production of either bitumen or synthetic crude oil. Each scenario included pipeline transportation to the U.S., refinement into gasoline or diesel, and combustion.

The team found that gasoline and diesel production from oil sands yielded, on average, about 20% greater emissions than fuel production from conventional crude oil, similar to previous estimates. The most intensive emissions came from in situ recovery of synthetic crude oil and the least intensive from surface mining of bitumen. The most common methods used in the industry, in situ recovery of bitumen and surface mining of synthetic crude, each had about 20% greater emissions compared with conventional crude production.

“This study takes a significant step forward in comprehensiveness and quality of its life-cycle emissions estimates,” says David W. Keith, an expert in climate science and energy policy at Harvard University. This is a politically hot topic, he suggests, and the study “helps to provide an evenhanded look.”.



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Steve Swedberg (June 24, 2015 1:56 PM)
While it is always desirable to have a perfect plant or production operation, the fact is that there are going to be pluses and minuses to any endeavor. I believe we should work to minimize negative effects but remember that there is value in what is being extracted.

By the way, the picture associated with this article shows great clouds of steam rather than massive air pollution. Heat and moisture will do that!
David Hrivnak (June 29, 2015 5:13 PM)
While I agree with your basic assessment we now have good alternatives. I power my electric car with fuel that is about $.80/gal. Then add to that thanks to rooftop solar I can make it myself and make it cleanly. Try that on any oil sand method.
Isaac (June 24, 2015 2:13 PM)
"about 20% greater emissions than fuel production from conventional crude oil, similar to previous estimates"

If these are similar to previous estimates, I guess I fail to see how this is news. Shouldn't the focus be on how to decrease this number not confirm it?
Elizabeth Fisher (June 24, 2015 3:44 PM)
This is a very misleading study and message. Refining, transport, and use in a vehicle create the same amount of CO2 whether it’s from oil sands or conventional oil so why include that in the comparison? Full life cycle analysis, ie “well to wheels” masks the huge increase in emissions during extraction and upgrading that oil sands create vs. conventional drilling.
It is the extraction and upgrading alone where the big difference in emissions is. Average green house gas emissions for oil sands extraction and upgrading are estimated to be 3.2 to 4.5 times as intensive per barrel as for conventional crude oil produced in Canada or the United States.
If you include all the parts where the emissions are the same that’s kind of like an 20 year old alcoholic comparing his drinking to a teetotaler by saying he averages one/drink a day over a lifetime. What he fails to say is that he drank nothing the first 18 years of his life, just like the teetotaler, but now drinks 10 martinis/day for the past 2 years… "one drink per day doctor!" Is that a healthy lifestyle? Are oil sands only 20% worse than conventional oil? NO
Oil sands extraction and upgrading emits 3.5 – 4.2 times as much CO2 and conventional extraction and upgrading. That’s what needs to be compared and it should not masked by the parts that are not related to the oil sands vs. conventional oil comparison.
For more detail see
Andrew Kaldor (June 24, 2015 6:55 PM)
I have not read the article referd here, but my comment relates to the base case comparison. US Gulf coast refineries use substancial amount of low cost heavy oil, much of which is comparable to bitumen delivered from Canada. The sources are Venezuela bitumen, Nigerian heavy crude, Chad heavy crude, the Mexian crude imported is also heavy, as isthe crude from Saudi Arabia. So the well to wheel analysis comparison should be with those kinds of crudes as feedstock. We already use substantial Canadian heavy oil/bitumen in the northern tier refineries today, from Illionis refineries to Montana refineries. I suspect that when we make like-to-like comparison the enhanced greenhouse gas conibution is much smaller.

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