The Trans-Alaska Pipeline
THE TRANS-ALASKA PIPELINE WAS the subject of an exhibit at the Center’s Los Angeles gallery over the winter. Among the longest oil pipelines in the world, the Trans-Alaska Pipeline is unique in its isolation and construction. In the mid-1970s, 100,000 forty foot sections of half-inch thick steel pipe were welded together, wrapped in insulation and an outer covering of sheet metal, and stretched across our emptiest state, in one fell swoop. 30 million gallons of crude still flow through it daily.
The Trans-Alaska Pipeline is a four-foot-wide, 800.32-mile-long pipe, built by 70,000 individuals in a little more than two years between 1975 and 1977, costing $8 billion in private money. It is owned and operated by the Alyeska Pipeline Service Company, which is itself owned by the oil companies that dominate North Slope oil production: BP (47 percent), ConocoPhillips (28 percent), and ExxonMobil (20 percent). It spans the entire state of Alaska, from top to bottom, bringing the entirety of oil extracted from the North Slope at Prudhoe Bay—the largest oil field in the United States—to market.
The pipeline created overland access across the Last Frontier (you can now drive to the American Arctic, if you like) and brought billions of dollars to natives, Alaskan residents, construction workers, and, of course, the oil companies. From north to south it is a physical line of connectivity, transposing buried hydrocarbon fluid from the frozen north edge of the continent to the ice-free port at Valdez, from where it travels, eventually, to the suburban driveways of the West Coast.
In another dimension, looked at from the side, the line is a barrier, a physical form, a tube on a terrestrial scale. The pipeline is remarkable especially because it is visible. Most pipelines are underground, as this one was originally expected to be when it was first proposed in 1968. But after drilling over fifteen thousand test borings along the proposed pipeline route, it was determined that 420 miles of the line were in permafrost. That does not make a stable bed for a pipeline carrying hot oil (which enters the line at over 120ºF) . The solution, which was unprecedented, was to raise the pipeline above the ground, forcing much of the structure into plain sight. This created the iconic image in space and our minds of a pipeline spanning the American wilderness, and everything that represents.
What follows are some of the points of interest along the line, giving a sense of the pipeline and the CLUI exhibit about it.
A Journey Down the Pipe
The North Slope oil fields are spread out across a forty-mile-wide zone along the coast of the Arctic Ocean, between the largely untapped National Petroleum Reserve, to the west, and the Arctic National Wildlife Refuge, to the east. Six thousand people work in this zone, though nobody lives there. Most work two week shifts, twelve hours a day, sleeping in company “mancamps” where all meals are provided (all you can eat, at no charge), after which the workers are flown back to their hometowns, all over the United States, for two weeks off. The weather, of course, is terrible.
The hundreds of production wells and processing facilities on the slope are connected to one another by elevated pipelines. Wastewater and gas are injected into the ground, pumped away, or burned. The oil is processed at oil company facilities all over the Slope.
The purified petroleum converges on Pump Station 1, the beginning of the Trans-Alaska Pipeline, seen here emerging from underground on the edge of the pump station, and heading south. The Alaskan pipeline is the only way for the oil from the fields of the North Slope to get out, to market. The pipeline is what makes these fields viable.
The oil flows at around four miles per hour, taking about a week to travel from Pump 1 to Valdez. To move the oil, eleven pump stations were built along the route. Each is a self-contained small industrial town. Due to a decrease in the volume of oil shipped, and changes in efficiency on the pumps, only six of the pump stations are currently pumping. Oil flow peaked in 1988, when 744,107,855 barrels of oil moved through the pipe (at a rate that exceeded than 2 million barrels per day). Now, with reduced production, around 710,000 barrels per day flow through the pipe, about 17% of United States crude oil production.
The Haul Road, now called the Dalton Highway, follows the pipeline along its northern half. It was the first part of the pipeline to be built, in 1974, as it enabled materials and equipment to be moved north from the Yukon River, 358 miles from the top of the pipeline route in the oil fields of Prudhoe Bay. Originally, it was intended to be a private industrial road, as was promised in order to get Congressional approval to build the pipeline. It opened to the public in 1995, however, and is now Alaska State Highway 11, though still mostly unpaved.
The highest point on the pipeline is Atigun Pass in the Brooks Range. Here the pipeline runs underground for eight miles in an insulated concrete box that protects it from avalanche damage.
In addition to the commercial truck traffic, the haul road has around twenty thousand visitors every year and the state has erected turnouts, pit toilets, and overlooks along its path. Most of the tourists come on tour buses, operated by Princess and Holland cruise lines, as a side trip for cruise packages that otherwise focus on Alaska’s southern coast. A popular stop for a group photo is the sign at the turnout where the haul road crosses the Arctic Circle.
Along this section of pipe, at the exact mid-point (Mile 400), on October 4, 2001, a hunter named Daniel Lewis shot the pipeline while on a drunken ATV trip with his brother. The hole produced by his .338 caliber rifle caused a jet of oil to spray 75 feet out, and almost 300,000 gallons of oil were spilled. The pipeline has been struck by bullets several times. Usually, the half-inch-thick steel just dents. Acts of sabotage have also occurred. The largest single spill from the pipeline was in February, 1978, when a bomb blast made a one-inch hole that resulted in 670,000 gallons being spilled. The people responsible were never identified. As a result of this incident, Alaska Senator Ted Stevens lobbied, successfully, to have destructive acts to the pipeline prosecuted as a federal offense.
The pipeline was designed to withstand earthquakes within a range of 5.5 to 8.5 on the Richter scale, varying according to estimated earthquake probability at points along its path. At the site believed to have the highest risk, where the pipeline crosses the Denali Fault zone, the pipe is on lowered risers that rest on elongated skids, allowing for up to 20 feet of lateral, and 5 feet of vertical movement. In November, 2002, a 7.9 quake occurred along the Denali Fault, its epicenter fifty miles west of the pipeline. The pipeline moved 7 feet laterally, and 2.5 feet vertically. Some of the support members of the pipeline were damaged, but no oil was spilled. The epicenter of the largest earthquake in American history, which happened in March 1964, was near Valdez, the pipeline’s southern terminus, and measured 9.2 on the Richter scale.
The Yukon River, which flows east to west, is a major aquatic artery for the interior of Alaska, and divides the state half. The half-mile-long bridge built for the pipeline and its haul road is the only road crossing of the river. The Arctic Ocean is 350 miles away, and the state north of the Yukon is virtually roadless, except for the Haul Road. The Yukon Bridge is the largest of the thirteen bridges on the pipeline. The pipeline makes more than 800 river and stream crossings, and it is buried under most of them, held down in a trench below the stream bed by large concrete anchors that straddle the pipe.
Where the line crosses roadways in permafrost zones, like at the Glenn Highway, a major road artery for the state, the pipeline goes underground. Here it is enclosed in material that is cooled by refrigerated pipes buried along side it. Pumping stations nearby keep the refrigerant circulating. In elevated sections, ammonia circulates from the base of the pipeline’s buried feet (which sometimes extend more than 150 feet into the ground) to radiators that extend from its supports and remove heat from the metal parts. As the ammonia cools, it condenses and drops back down to draw the heat out again. This is a circulatory system unaided by pumps.
Thompson Pass, 776 miles downstream from Pump Station 1, is the crest of the last mountain range that the oil has to flow over. The south face of the pass is nearly vertical in places, which made this the most difficult part of the pipeline to construct. Welders and equipment had to be dangled by ropes to work on the slope. From this point, the pipeline remains buried for its final, home stretch, downhill, to Valdez.
The pipeline emerges from the ground for the last time and enters the East Manifold Metering Building at the Valdez Marine Terminal. From the metering building it goes either into storage tanks, or directly into tankers, parked at one of four berths. Nearly 20,000 thousand tankers have come and gone from Valdez since the pipeline opened in 1977, carrying more than 15 billion barrels of oil to refineries near Seattle, San Francisco, and Los Angeles.
The inlet of the Port of Valdez opens into Prince William Sound, and departing tankers entering the Sound keep a straight course southwest for twenty miles, then turn southeast once they get beyond Bligh Island and its adjacent reef. On March 24, 1989, the Exxon Valdez was piloted by the ship’s third mate (the captain was sleeping off a few drinks he’d had at the Pipeline Club restaurant before leaving). The ship steered too far east, to avoid some icebergs, a common presence in that part of the Sound, and ran aground on Bligh Reef, spilling 250,000 barrels of oil into the ocean. Since then, a tower has been constructed, to make the top of the reef more visible. ♦
The CLUI exhibit was made possible by a grant from the Seed Fund, Studio for Urban Projects, and the CLUI Petro-America Program. The photoscape presentation includes 280 images. Audio used for the exhibit was Dark Waves, by John Luther Adams, a composer based in Fairbanks, Alaska.