Just How Dirty Is Canada’s Oil?

Canada’s Alberta Province tar sands are a viscous bitumen, described as peanut-butter thick, that releases more carbon dioxide than other forms of oil. Just how much more is debated. We’ll get to that.

The first strike against the oil is that to get at the sand requires felling the natural carbon reservoir of the original boreal forests. The doubling to 1.8 million barrels of tar sands production daily that is projected by Canada's environmental ministry over the coming decade leads to cutting down some 740,000 acres of trees that will release their carbon into the atmosphere.

Bitumen near the surface is strip mined. The deeper bitumen is drilled for. Strip-mining uses the world’s largest dump trucks to carry the sludge to nearby separation plants, where the tar sand is crushed and about 3 to 4 gallons, or about 11.5 to 15 liters, of water are used for every gallon of oil produced to separate the bitumen from the sand. It is, however, a region well endowed by lakes and rivers.

Natural gas is used to cook the strip-mined bitumen to release its oil. In drilling, a great deal more natural gas is burned to produce steam that is injected into a well under high pressure to melt its dense oil-bearing bitumen enough for it to flow to the surface.

In either process, liquid chemicals are added to convert the softened bitumen to “dilbit”, industry parlance for “diluted bitumen”, the consistency needed for the substance to flow through a pipeline.

A strip-mine in Alberta
Waste water — a residue of sand, water, contaminants and bitumen that slipped past the filters — is sent to “tailing ponds” that so far occupy 170 square kilometers (66 square miles) in the area. The mixture is toxic and leaks into the water table and streams, or so it is alleged by the Natural Resources Defense Council (NRDC), an environmental group, but that is denied by Canada. The companies try to frighten migrating birds away from the ponds with scarecrows and propane cannons. That did not work in one case where 1,600 migrating ducks landed on the ponds and died.

Can anything be done to reduce what is undeniably an ugly process. There are improved experimental practices in the works. One pumps water into separate wells surrounding a production well. Electrodes are placed down-well and current heats the sand until the bitumen eventually softens enough to be pumped up and out. Another way is to burn bitumen down-well, which melts the bitumen around it. But it is an industry resistant to change, say the companies developing these techniques.

Gauging by how much the greenhouse gas emissions of Canadian tar sands oil exceed other forms of oil depends on where along the life cycle of the oil one takes measurements. The extraction processes in isolation are what raise the most alarm. They triple the greenhouse gas emissions of regular drilling, according to the NRDC. At current production levels, the organization says these processes produce every day the greenhouse gas equivalent of 12 million cars, burning enough natural gas to heat six million homes.

The nonpartisan Congressional Research Service (CRS) undertook a survey of published studies and concluded that the “well-to-tank” stage of Canadian oil — that is, extraction up to the point just short of the oil being burned — results in 70% to 110% higher greenhouse gas emissions than for the weighted average of transportation fuels consumed in the United States.

But across the "life-cycle" of this oil, 70% to 80% of its emissions are produced by its burning at the end point and that shrinks the weight of the more elevated extraction emissions. The industry therefore prefers take the measure of the entire “well-to-wheels” life cycle of the oil from the removal of bitumen from the ground to when it is finally burned in a furnace or vehicle. That produces a more favorable comparison to other forms of oil because it brings in factors that are likely to be the same for all types of oil. All have to be transported, for example, at an equal cost of carbon dioxide emissions.

IHS CERA, a prominent global industry consultancy based in Colorado, originally reported that, well-to-wheels, the Canadian oil is only 5% to 15% dirtier than the average crude oil consumed in the U.S. But it then found a way to revise that downward to only 6% by basing the comparison “on the actual composition of oil sands exports to the United States instead of an overall range for oil sands produced in Canada”.

Some measurements leave out the extraction cycle and focus only on what the U.S. would experience, on the grounds that the tar sands oil would be extracted anyway. But in its final usage the oil derived from tar sands is nevertheless more carbon intensive. The Congressional Research Service estimates that, depending on amounts imported, the Keystone XL pipeline would increase U.S. greenhouse gas emissions by 3.7 to 20.7 million metric tons annually. That’s the equivalent of "approximately 558,000 to 4,061,000 passenger vehicles" compared to more conventional oil.

Well-to-wheels, the CRS rates Canadian tar sands oil as 14% to 20% higher in greenhouse gas emissions compared to oil from other sources. They say that well-to-wheels emissions from Canadian oil sand crude are from 9% to 19% higher than Middle Eastern sour, 5% to 13% more emission-intensive than Mexican Maya, and 2% to 18% more intensive than various Venezuelan crudes.

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