In a finding that should resonate strongly for Canadian decision-makers charged with meeting the country’s climate targets, new research reveals that the carbon footprint of a litre of synthetic crude extracted from tar sands/oil sands bitumen is more than 23% greater than previously estimated.
The elevated figure, reported by InsideClimate News, is based on an assessment conducted by the U.S. State Department in the course of its consideration of a still-pending application by Calgary’s Enbridge Inc. to expand its Alberta Clipper pipeline to deliver synthetic tar sands/oil sands crude to Wisconsin. It updates an earlier finding produced by the same agency in 2014, during its consideration of TransCanada Corporation’s Keystone XL pipeline.
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That assessment, ICN recalls, determined that “compared to other sources of oil that American refineries might use, the tar sands would be about 17% more polluting on average.” The calculation contributed to then-President Barack Obama’s decision to reject  the Keystone XL proposal, a decision recently reversed  by his pro-fossil successor.
A more recent review of Enbridge’s proposed line, however, produced “a gloomier picture of emissions.”
Employing “the most up-to-date studies and tools, including a model known as GREET, developed by the federal Argonne National Laboratory, which calls it the ‘gold standard’ for this kind of calculation,” the latest assay found that on a comprehensive “well-to-wheels” basis, “tar sands crude would have a carbon footprint of 632 kilograms per barrel, compared to an average U.S. refinery mix of 521 kilograms per barrel of carbon dioxide emissions. The difference is 111 kilograms per barrel—21 percent dirtier, not 17 percent.”
The four percentage-point difference in the new calculation means the full carbon footprint of tar sands/oil sands production, distribution, and use is 23.5% heavier than previously thought.