Today, the EU backed off its plan to label oil sands from Canada as dirtier oils. Behind this move was years of lobbying by the Canada officials and industry, as well as a signal of oil sands rising to a strategic importance.

Oil sands, or tar sands, is a mixture of sand, water, and bitumen. 81% of the extractable oil sands are found in Canada, making the nation’s proved oil reserves rank the third globally. The U.S. is one of its main crude oil buyers.

Shale oil is another type of unconventional oil, the production of which has been on the rise ever since the American shale revolution. However, as the U.S. proved reserves have dropped since 2012, there have been debates over increasing crude import or continuing to self-support with shale oil. While economics and national strategies play important roles in the energy future, the environmental costs need to be calculated too.

Oil sands

Canada, particularly Alberta, has oil reserves of 170 billion barrels, which seems to show a bright economic promise. To obtain the energy, however, a huge amount of energy has to be used. Studies show that to one unit of invested energy can extract 25 units of conventional oil; the same amount can only get 5 units of tar sands oil. For oil sands deeper buried in the earth, the ratio even drops to 2.9 to 1.

Oil sands extraction is also very water-consumptive. For each barrel of oil produced, 2 to 4.5 times the amount of water as well as chemicals are required to wash the sand; and roughly 3 million gallons of toxic runoff occur every day. The highly toxic discharge, as well as potential air pollution pose a huge threat to the water, land, wildlife, and human health.

The extraction, production and refining processes contribute to enormous GHG releases, not only through direct discharge, but also through destroying boreal forests, which are an important carbon sink.

Another big concern with oils sands is the transportation. An extensive and pricey pipeline system has to be built to transport oil to faraway markets. Oil leak, pipeline failure, and other incidents are a potential threat.

Oil shale

The acquisition of oil from shale requires intensive drilling and fracking. Fracking pumps tons of water mixed with chemicals and sands into the rock to release the gas and oil, which causes polluted water runoff that contaminates the groundwater.

High GHG emissions also occur throughout the extraction, production, transportation, and consumption. Shale oil is usually associated with natural gas,  which contains 80-95% methane, a GHG much more powerful than CO2 in capturing heat.

Like tar sand oil production, long-distance transmission is another problem, requiring the establishment of expensive and risky pipelines. In addition, on the ocean sites where the oil is extracted from under the sea, tanker ships that are employed to transport over water have potential dangers too, such as spills.

Ultimately, both tar sands oil and shale oil are fossil fuels. The calculation of an energy source intertwines with economics, politics, and social preferences. However, from the environmental perspective, neither is considered clean.