tar sands

Tar sands (sometimes referred to as “oil sands” or, more technically, bituminous sands) are sand or sandstone that contain a very dense and extremely viscous form of petroleum known as bitumen. Bitumen is considered an “unconventional” source of oil because significant processing is required to transform it into commercially useable oil. The current primary source of bitumen is the vast tar sands deposits of Alberta, Canada.

Typically, tar sands are strip-mined and the bitumen cooked out, making the greenhouse gas and energy footprints of tar sands oil far larger than that of conventional oil. The energy returned on energy invested of tar sands is between 3:1 and 5:1 — much lower than conventional oil — making tar sands an exceptionally high-cost and low-net-energy oil.

Tar sands oil production also requires great quantities of water, causes deforestation on a massive scale (compounding global warming as a result of the removal of the boreal forest ecosystem, one of the world’s most effective terrestrial carbon sinks), and leaves behind toxic lakes of wastewater slurry. Levels of carcinogens in regional waters have been found to be significantly higher near the Alberta tar sands, greatly impacting First Nation communities who are heavily reliant on the local ecosystem for their livelihoods and food.

Tar sands oil currently makes up less than 5% of global oil production. The industry and its proponents want to significantly increase that figure by expanding access to the global market through pipelines which can carry diluted bitumen to coastal ports. A number of pipelines are being built or are under consideration, primarily connecting Alberta to West Coast ports and Gulf of Mexico ports. However, resistance to these pipelines (and the commitment they represent to increased dependence on one of the world’s dirtiest sources of energy) has grown — particularly to the proposed Keystone XL pipeline in the United States and the Northern Gateway Pipeline in Canada.


Further Reading