The tar sands oil reserves in Alberta, Canada, represent the second largest proven petroleum reserve in the world -- right behind the reserves in Saudi Arabia. The Alberta tar sands are located in the vast boreal forest of Canada, just north of Montana, and it is estimated that nearly 179 billion barrels of oil are in the tar sands, according to Bridget Mintz Testa, writing in the peer-reviewed journal Mechanical Engineering (Testa, 2008). The great volume of crude oil is seen as a positive, reliable source of energy for Canada and other countries that will be importing this oil. The extraction, production, and transportation of tar sands oil also represents a number of serious environmental impacts, which will be reviewed in this paper.
The Science Involved in Tar Sands Oil Production
Notwithstanding the fact that tar sands oil is in plentiful supply, one of the down sides of the equation is that tar sands oil is not easily extracted, which poses stiff challenges for oil companies that are unlike the challenges confronted when oil companies extract oil from traditional wells in Texas, or Saudi Arabia, or in other parts of the world. The crude that is extracted from the tar sands is a low grade kind of crude called bitumen, a "…black, oily, viscous" substance that naturally occurs as an organic byproduct of "decomposed organic materials" (Hirst, 2013). Bitumen has been utilized in myriad ways through world history; in ancient Egypt bitumen was used in the mummification process; in prehistory bitumen was used as "a sealant, as adhesive, as building mortar, as incense…" and even for decorative designs on pots and buildings (Hirst, p. 1). In fact Neanderthals used bitumen to fasten ivory shafts to sharp-edged tools in the Hummal archeological site in ancient Syria, and Native Peoples in the Middle East used bitumen to waterproof their reed canoes (Hirst, p. 1).
The Extraction Process at the Tar Sands Mines
Mining / extracting bitumen is a process that includes "…scraping the stuff on the surface" (Testa, 31). To get the bitumen out of the ground the first thing that has to be done is clear-cut the forest over the site to be exploited. Once the forest is logged, the next step is to scrape away the "…rich topsoil" and store that topsoil away for reuse when needed to fill in areas previously scraped away (Testa, 31). The next step is removal of the "overburden -- the material that lies atop the oil sands… which are generally less than 70 meters below the surface…" but in some cases the oil sands are up to 90 meters below the surface (Testa, 31).
In the past the bitumen was harvested using draglines and bucket-wheels (equipment that was "the size of multistory buildings") to dig up the oil sands that were mixed with clay, Testa continues. Once the oil sands were in the huge buckets, they traveled on "…miles-long conveyor belts" that carried them to extraction facilities where they were dumped into huge drums and mixed with "…a witches brew of steam, hot water, and caustic soda, and heated to 80°C (175°F) (Testa, 31). The over-heated water and fierce pressure caused the bitumen to rise to the top and the sand and clay sank to the bottom. That was the original process through which bitumen was achieved. It was very expensive and energy-intensive and so the strategy was changed to what it used today in Canada.
The most recently evolving strategy for harvesting bitumen is by what is called "steam-assisted gravity drainage" (SAGD), which is not in full production but is seen as a less environmentally disruptive process. Basically two wells are drilled (about 200 meters deep) separated vertically by about 16 feet, Testa explains (32). Steam is injected through one of the wells (the steam is about 450°F) for about six months before the bitumen comes up the other well; in 18 months, Testa reports, the well can be expected to be up to peak production
In the meantime, what works most efficiently is a process whereby the raw oil sands are not sent directly for extraction; instead, a "tooth crusher known as a feeder-breaker chews them into smaller pieces" and those pieces are sent by conveyer to a "cycle-feeder" (a tub of "swirling water") (Testa, 32). Tumblers (with the "same witch's brew" as before) separate the bitumen from the oil sands, but the water is only 25°C in most cases. The bitumen then is transported to a refinery where the oil company doing the work, Syncrude, takes out the sulfur and adds hydrogen to convert the bitumen "…to high-quality, light, sweet crude oil," Testa continues (32).
Since 1970 the production of oil from tar sands in Canada has skyrocketed to nearly 1,400 barrels per day (Illustration courtesy
, 2010, Schindler)
Oil Tar Sands - Pros
The demand for new energy sources has grown along with the population and with industrialization throughout the world. Every industrialized nation needs oil for the production of electricity and other uses, so the huge deposits of oil in the tar sands in Alberta is a significant potential supply for that much-needed oil. "The world is looking for energy from responsible (oil) producers," according to Diana McQueen, Minister of Environment and Sustainable Resource Development for the Province of Alberta (Hall, 2013). "Developing tar sands is important to Alberta," McQueen said, "but what's equally important is our environment" (Hall, p. 2).
To the question of transporting oil from tar sands through pipes intended for cleaner crude oil, McQueen said that "…Basically, by the time tar sands leave the plant gate, they're a diluted heavy oil that meets pipeline specs," she continued. "Is it fair to say to other countries that they can't have what we have?" she asked. "Alberta has stepped up to the plate," she concluded (Hall, 2).
The Government of Alberta published a pamphlet called "Albert's Oil Sands: Opportunity. Balance" which is basically a promotional review of why the tar sands oil is important not just to Alberta but to other places in the world. "Fossil fuels continue to be the dominant form of energy -- accounting for 86% of energy consumption around the world" (Podlubny, 2008). One of the criticisms of the Alberta tar sands (the oil companies and Alberta's government prefer to call it "oil sands" than "tar sands") is that the sprawling boreal forest is being harmed; the government's response is that the boreal forest covers 381,000 square kilometers (147,000 square miles) but the "entire minable area in the oil sands covers 3,500 square kilometers (1,350 square miles), less than 1% of the boreal forest area" (Podlubny).
As to concerns about the carbon footprint created through the production of tar sands oil, the government understands that "…more energy is needed to produce a barrel of oil than conventional oil…but the gap is closing… for example, per barrel of oil, carbon dioxide emissions have been reduced by 45% since 1990" (Podlubny). In fact, in 2007, Alberta became the first territory or state or nation to "…legislate mandatory greenhouse gas reductions for large industrial facilities."
In addition, Alberta's Water Management Framework has placed "strict limits" on industry water use, and during periods of low river flow (on the Athabasca River, which is used for water needs in the process of separating the oil from the sand) "…water consumption is limited to the equivalent of 1.3% of annual flow…and Industry is doing its part…up to 90% of the water used (in the process) is recycled" (Podlubny).
The tailings ponds -- a great concern to environmentally concerned organizations because of the number of birds that die when landing in the oily ponds -- are constructed with "groundwater monitoring and seepage capture facilities," the Alberta government insists. The ponds are "…closely monitored to ensure any seepage is minimized so there are no impacts to surface water" (Podlubny). The sediments on the banks of the Athabasca River do receive "natural contaminants" but it is not due to bitumen production, the government asserts; rather this contamination is caused by the naturally seeping tar sands. In addition, "Stringent testing has consistently shown there has been no increase in concentrations of contaminants as oil sands development has progressed" (Podlubny).
As for mercury contamination, the Alberta government claims that the water entering Lake Athabasca has contained a "maximum of eight parts per trillion," which is well below the guideline of 13 parts per trillion. Arsenic, too, is below guidelines, the government explains.
The American Petroleum Institute claims that approval of the Keystone XL pipeline, which would bring tar sands oil south through the U.S. heartland and into Texas, could enhance domestic energy security and "reduce…reliance on energy resources from less stable regions" (API).
What is the Newest Process to Remove Bitumen from the Sand?
In the journal Chemical Engineering an article describes the latest method -- which is being tested early in 2013 -- for separating bitumen from the tar sand. Instead of steam being pumped into the…