Trans-Alaska Pipeline

/trans"euh las"keuh, tranz"-, trans'-, tranz'-/

a pipeline system opened in 1977 that transports oil 800 mi. (1300 km) across Alaska, from Prudhoe Bay on the North Slope S to Valdez harbor.

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or Alaska Pipeline

Oil pipeline running 800 mi (1,300 km) north-south across Alaska, U.S. Completed in 1977, it transports crude oil from the oil fields of Prudhoe Bay on the Arctic Ocean to an ice-free port at Valdez.

To avoid thawing the adjacent permafrost, about half of the line is elevated.

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▪ pipeline, Alaska, United States

 pipeline that connects the oil fields of Prudhoe Bay, Alaska, with the harbour at Valdez, 800 miles (1,300 km) to the south.

 The discovery of oil on Alaska's North Slope in 1968 spurred the creation of a safe and efficient way to bring those reserves to market. Atlantic Richfield Company, British Petroleum (now BP PLC), and Humble Oil (a subsidiary of Exxon Corporation) agreed to build a pipeline that would connect the North Slope to Valdez, an ice-free port on Prince William Sound. The movement of oil through the 48-inch (1.2-metre) pipe would be boosted by pumping stations situated along its length, ensuring a constant flow at roughly 4 miles (6 km) per hour. At this rate, oil would complete the journey from Prudhoe Bay to Valdez in about nine days.

      A series of environmental impact studies were commissioned, and their results led to changes in the pipeline's design that would allow wildlife to pass more easily over or under it. On Nov. 16, 1973, President Richard M. Nixon (Nixon, Richard M.) signed the Trans-Alaska Pipeline Authorization Act into law, and much of the next year was spent building access roads along the proposed route. Construction on the $8 billion pipeline began on March 27, 1975. The final weld was completed at Pumping Station 3, near Atigun Pass, on May 31, 1977, and oil began to flow through the pipeline on June 20. However, a series of mechanical problems halted the pipeline's operation, and oil did not arrive at Valdez until July 28.

 In spite of these difficulties, production continued, and the pipeline moved its billionth barrel of oil in early 1980. Attention was focused on the southern terminus of the pipeline in 1989 when the tanker Exxon Valdez ran aground in Prince William Sound. Images of oil-slicked sea birds and otters provided stark examples of the dangers of an oil spill in the Arctic. Though of a smaller scale than the Exxon Valdez disaster, the largest spill in the history of the pipeline occurred in 2006 when a transit pipe at BP's Prudhoe Bay facility ruptured. More than a quarter million gallons (one million litres) of oil spilled onto the tundra, and Prudhoe Bay production was halved as engineers spent months replacing corroded pipe.

 

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