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Alberta Innovates report shows more study is needed to assess corrosivity of tar sands and Canadian heavy crude

Anthony Swift

Posted November 29, 2011

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A report on pipeline corrosion released by Alberta Innovates recently evaluated evidence of diluted bitumen’s corrosivity relative to conventional crude. The Alberta Innovates report noted that there is no peer reviewed research on this issue, identified gaps in safety data kept by regulators, and found that many of the corrosive properties of diluted bitumen are shared by certain blends of very heavy Canadian crudes. However, the report went one step too far when it assumed that corrosive properties diluted bitumen shares with certain very heavy Canadian crudes do not present increased risks to pipelines. Like diluted bitumen, the production and export in pipelines of large volumes of heavy Canadian crudes is a relatively recent development which has not been accompanied by adequate due diligence on the part of regulators and the industry. The fact that pipelines are moving increasing volumes of unconventional crudes which share some of diluted bitumen’s corrosive characteristics only increases the urgency for appropriate scientific study. 

In the report Tar Sands Pipelines Safety Risks, NRDC compared diluted bitumen to the West Texas Intermediate (WTI), the benchmark crude of North America. The reason that NRDC chose WTI as a point of reference is that it is similar to the conventional crudes historically moved on the U.S. pipeline system. These conventional crudes are lighter and less viscous, and therefore can be transported at lower temperatures and pressures than thick tar sands crude.

The Alberta Innovates report compared diluted bitumen with five blends of very heavy Canadian crude. These blends of heavy crude differ significantly from the lighter oil pipelines were designed for – even from conventional heavy crude. Like diluted bitumen, these heavy Canadian crudes require unconventional production methods, must be mixed with diluents to move in a pipeline and have been transported on some of the same pipelines which have shown signs of wear and tear in the United States. In many cases, these heavy Canadian crudes have to be upgraded into synthetic crude before being processed by conventional oil refineries. Simply stated, the blends of Canadian heavy crude that Alberta Innovates considered are far more similar to tar sands diluted bitumen than they are to the lighter crudes that historically have been moved by the onshore pipeline system.

Also like tar sands diluted bitumen, the production and export of significant quantities of heavy Canadian crude on the U.S. pipeline system is a recent development. Combined exports of heavy crude and diluted bitumen have increased over four-fold over the last fifteen years, from less than a quarter million barrels per day (bpd) in 1995 to over a million bpd last year.

This development has been accompanied by early warning signs. The pipelines moving the bulk of this crude in the United State’s upper Midwest spilled nearly three times as much crude per mile as the national average between 2007 and 2010. Enbridge’s line 6B, which spilled over 840,000 gallons of diluted bitumen in Michigan and on which hundreds of corrosion abnormalities have been identified, has been used to move large quantities of Canada’s heavy crude and diluted bitumen exports.

The Alberta Innovates report also noted that large diameter pipelines in Alberta have rates of internal corrosion that are comparable to those in the United States. This is actually a sign of trouble, as the U.S. pipeline system is on average twice as old as the Alberta pipeline system. Because the risk of internal corrosion increases with pipeline age, the newer Alberta pipeline system should also have a significantly lower rate of internal corrosion. That it doesn’t is evidence of a potential problem.

There is significant evidence that more study and enhanced safety standards are needed for the pipeline transport of viscous, unconventional crudes like diluted bitumen.  Alberta Innovates identifies some of these gaps and and urges Alberta's regulator, the Energy Resources Conservation Board, to start separating safety and operating statistics for pipelines that carry tar sands crude from those that ship conventional oil to allow better information gathering. NRDC agrees that this better collection of information is an important first step.

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Government of AlbertaNov 29 2011 04:44 PM

Dilbit has been shipped through thousands of kilometres of pipelines in Alberta for decades. Dilbit is a homogenous mixture – its ingredients do not separate until you refine it, just like crude oil. Spill it, and it remains dilbit.

The NRDC has made it clear that it will twist any science, bend any logic, and make any argument to oppose oil sands development. We desire a factual discussion. This will not come from the NRDC.

- David Sands, spokesman, Government of Alberta

Anthony SwiftNov 29 2011 06:00 PM

Where are these thousands of kilometers of pipelines that have been moving dilbit for decades? Take a look at this inventory of tar sands infrastructure and you’ll see that until recently, bitumen mining capacity linked with on site upgraders. ( ) The two early tar sands mines built in ’67 and ’78 had upgraders located on site to convert diluted bitumen to synthetic crude. The 70k bpd of Cold Lake production that came on line in the mid-80s was served by the Husky upgrader 30 km away (which also upgrades blends of Canadian heavy crude used in Alberta Innovates’ report). The inventory shows a rapid increase in tar sands projects starting in the late 90s (which is when Enbridge started moving it on its pipelines).

As far as the behavior of dilbit when it spills, the emergency responders working the Kalamazoo dilbit spill have found otherwise. Mark Durno, EPA’s spill coordinator has said of the spill, “The submerged oil is a real story -- it’s a real eye-opener… In larger spills we’ve dealt with before, we haven’t seen nearly this footprint of submerged oil, if we’ve seen any at all.” ( ) EPA was not expecting that, and had the proper due diligence been done, we would have known what to expect before contending with this spill.

This is what we know, and frankly, the problem is that there are too many facts that we don’t know. NRDC is asking that the necessary study be done so we have all the facts necessary to have an informed discussion. Is that truly unreasonable?

conusamNov 30 2011 08:47 AM

I say let's investigate the NRDC because this organization is taking in millions in donations and paying themselves big bucks ex. JOhn adams and Ms. beinecke -but that's okay apparently.

"This is what we know, and frankly, ....YOU KNOW NOTHING!

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