1977

Trans-Alaska Pipeline

Imagine that you have discovered a major new source of crude oil—twice as big as anything else in North America. The oil is plentiful (eventually reaching two million barrels a day), but there is one minor problem—the well is in the middle of nowhere far above the Arctic Circle.

For engineers, the question becomes, “What is the safest and most efficient way to get the oil from the well to its market?” Engineers settled on a hybrid approach: An 800-mile -long pipeline (1,300 km) moves the oil overland across a north-to-south traverse of Alaska, and then supertankers carry the oil from the port in Valdez, Alaska, to refineries.

A pipeline is just a big pipe, right? First, it’s not quite that simple. Second, the unique engineering problems of Alaska came in several forms: 1) Keeping the permafrost near the pipeline from melting, 2) Dealing with earthquake activity, and 3) Keeping the oil flowing in such cold temperatures.

Oil flow is handled with eleven massive pumping stations (able to pump in excess of 60 million gallons of oil per day). The pumps keep the oil warm, pressurized, and flowing through the 4-foot-diameter (1.22 meters) pipeline.

Burying a pipeline full of hot oil naked underground would melt the permafrost, creating erosion and wildlife problems. When the pipeline must be buried, it is done using foam and gravel linings along with chillers. That’s expensive. Therefore, the vast majority of the pipeline is above ground. The pipe rests on horizontal beams. The beams attach to vertical posts. The posts contain heat pipes that dissipate heat into the air.

The pipeline, commissioned in 1977 by the Alyeska, can move side to side on the horizontal beams. That ability to move, combined with a serpentine path for the pipeline, lets the pipe shift during expansion and contraction. It also offers earthquake protection.

Along the Denali Fault, the pipeline rests on beams approximately 50 feet (15 meters) long. In 2002, a magnitude 7.9 earthquake proved that the system worked when the ground along the fault shifted by 14 feet (4.26 meters).

Engineers solved 800 miles of problems to create a workable solution.

SEE ALSO Oil Well (1859), Seawise Giant Supertanker (1979), Earthquake-Safe Buildings (2009).

The trans-Alaska oil pipeline during a July snow shower.