miércoles, 9 de noviembre de 2011

Panorama apocalíptico de la explotación de bitumen en Alberta, Canadá

Hay gran oposición en estados Unidos a la construcción de un oleducto Keystone XL para arenas bituminosas desde yacimientos en Canadá, que atravesarían todo el país hasta las refinerías en Texas en la costa del Golfo de México, creando innumerables puntos de riesgo ambiental  alteración de la biodiversidad.

Recientemente se presentó una protesta pacífica frente a la Casa Blanca para solicitar la cancelación de este proyecto. Hay bastante molestia pues el operador del proyecto, Transcanada, ha seleccionado la empresa que evaluará el impacto ambiental del mismo.

A continuación unas imágenes del gran impacto ambiental de este tipo de explotación publicadas por la revista Wired y una descripción de las arenas bituminosas tomada de Wikipedia (en Inglés).

Panorama apocalíptico de la explotación de bitumen en Alberta, Canadá
ORIGINAL: http://www.wired.com/wiredscience/2011/11/oil-sand-landscapes/

A Very Big Pit

Image: Suncor's Millennium Oil Sands Mine. The yellow spots at upper right are among the largest trucks in the world. (David Dodge/Pembina Institute)

The Boreal Forest

Alberta's boreal forests are part of a subarctic biome that crowns North America. Growing on land shaped and scraped by glacial scouring, many of its plant and animal communities have evolved undisturbed since the last ice age. Boreal wetlands are a critical breeding habitat for almost half of all bird species found in the United States and Canada.
Image: Boreal forest along the Athabasca river. (Pembina Institute/Flickr

Tar Sands Mining

Unlike conventional, easily accessible oil deposits, tar sands petroleum is mixed with sand and clay and water, creating a thick slurry that is trucked to processing centers for refinement. Roughly one ton of sand is needed to produce one barrel of oil, and the Caterpillar 797B trucks used to carry tar sands are the largest in the world.
Water used in refinement — a mix so toxic that waterfowl die after landing in it — ends up in tailings ponds, which often leak.
Image: The Athabasca river (top left) runs by a Suncor upgrading facility and tailings ponds. (David Dodge, CPAWS /Pembina Institute/Flickr)

Tar Sands Mining: The Extent

According to the Pembina Institute, tar sands mining now occupies an area of about 260 square miles. The total minable region is roughly 770 square miles.
Image: Boreal forest edges a Suncor surface mine. (David Dodge, CPAWS /Pembina Institute/Flickr)

Tar Sands Drilling

While surface mining gets the most attention, most of Alberta's tar sands are locked in deposits too deep to access with truck and shovel. Instead these are extracted by a process of drilling and steam injection that forces oil to the surface.
"The drilling companies say, 'We're after the deeper oil. We don't have the same footprint.' But that's not true," said Grant. "It pollutes more. It's going to fragment a much larger area with pipelines and roads and facilities. It will fragment an area that's dominated by wetlands. Scientists say it's actually as impactful as the mining."
Image: Nexen's Long Lake facility. (Pembina Institute/Flickr)

A Big Footprint

Canadian government-approved drilling permits already cover 30,000 square miles of forest and wetlands, said Grant, and could ultimately span 50,000 square miles — an area larger than Ohio.
Image: Pembina Institute/Flickr


Tar sands oil comes at a steep environmental price, and there's controversy over how many jobs would be generated by the Keystone XL pipeline -- but especially in Alberta, there are direct and immediate economic benefits.
Image: A sign in Fort McMurray, Alberta, the city closest to the tar sand surface deposits. (David Dodge/Flickr/Pembina Institute)

Unknown Limits

Tar sands mining has grown faster than expected "and as a result they couldn't put environmental protection plans into place — wetlands policies, contaminant limits," said Grant. "What concentrations of pollutants are acceptable in the Athabasca river? What limits will protect air, land and water? We're continually now playing catch-up. Nobody has that information."
Image: Tailings ponds. The Athabasca River flows past in the upper left corner. (Jennifer GrantPembina Institute/Flickr)


Though oil companies and government officials say mined lands will be restored, that's easier said than done — if anyone is even trying. Drained wetlands don't refill easily, and forest communities that evolved for thousands of years are very different than tree plantations.
Out of the 260 square miles mined so far, less than one square mile has been certified as reclaimed, Grant said.
Image: A Syncrude reclamation site. (Pembina Institute/Flickr)

After Keystone

If President Obama rules against Keystone XL, it won't stop tar sands mining and drilling, but building other pipelines won't be easy. The leading post-Keystone candidate is the Enbridge Northern Gateway Pipelines Project, which would run from Alberta to the coast of northwestern British Columbia. Indigenous and coastal fishing communities will likely oppose the intrusion. "I feel like it's not a project that will be easy to get approval for," Grant said.
Image: A Syncrude upgrader. (David Dodge/Pembina Institute/Flickr

The Big Decision
In the words of environmentalist Bill McKibben, Keystone XL represents "a decision point about whether, now that we’re running out of the easy stuff, we’re going to go after the hard stuff."
After more than a century of fueling civilization with fossils, the easy oil — those places where dead plankton and algae accumulated for millions of years in prehistoric seas, were entombed at just the right pressure and temperature for millions more, then arrived after the tectonic upheavals of multiple geological ages in spots easily tapped by big metal straws — is nearly gone. What remains are places like Alberta's tar sands.
"Until five or six years ago, nobody knew tar sands were different than conventional oil drilling," said Grant. "There's been a shift in public engagement and public concern. There are policies indicating that the world is shifting away from higher-carbon oil towards a cleaner-energy economy. There's reason to be hopeful."
Image: The Athabasca river. (David Dodge, CPAWS/Pembina Institute/Flickr)


Bituminous sandscolloquially known as oil sands or tar sands, are a type of unconventional petroleum deposit. The sands contain naturally occurring mixtures of sand, clay, water, and a dense and extremely viscous form of petroleum technically referred to as bitumen (or colloquially "tar" due to its similar appearance, odour, and colour). Oil sands are found in large amounts in many countries throughout the world, but are found in extremely large quantities in Canada and Venezuela.[1]

The crude bitumen contained in the Canadian oil sands is described by Canadian authorities as "petroleum that exists in the semi-solid or solid phase in natural deposits. Bitumen is a thick, sticky form of crude oil, so heavy and viscous (thick) that it will not flow unless heated or diluted with lighter hydrocarbons. At room temperature, it is much like cold molasses".[2]Venezuelan authorities often refer to similar types of crude oil as extra-heavy oil, because Venezuelan reservoirs are warmer and the oil is somewhat less viscous, allowing it to flow more easily.

Oil sands reserves have only recently been considered to be part of the world's oil reserves, as higher oil prices and new technology enable them to be profitably extracted and upgraded to usable products. They are often referred to as unconventional oil or crude bitumen, in order to distinguish the bitumen extracted from oil sands from the free-flowing hydrocarbon mixtures known as crude oil traditionally produced from oil wells.

Making liquid fuels from oil sands requires energy for steam injection and refining. This process generates two to four times the amount of greenhouse gases per barrel of final product as the "production" of conventional oil.[3] If combustion of the final products is included, the so-called "Well to Wheels" approach, oil sands extraction, upgrade and use emits 10 to 45% more greenhouse gases than conventional crude.[4]

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