Ballpark Estimate: $8 Billion (1997 dollars)
OIL – needed in enormous quantities by both the industrial as well as the rapidly developing third-world countries, it is a commodity that significantly influences the economy of many major governments. For this reason, when Atlantic Richfield and Humble Oil (now Exxon) announced the presence of oil in Prudhoe Bay, Alaska in 1968, the largest oil field in North America and the eighteenth largest in the world, the U.S. Government took notice. Extracting the oil from the frozen and pristine wilderness would be a major engineering feat, but transporting it to the refineries was another matter of serious concern. Following a number of surveys the only reasonable and cost-effective means for transporting the crude oil from Prudhoe Bay to the closest seaport was determined to be by pipeline.
Building the Pipeline
Consequently, in 1973 President Richard Nixon approved the construction of the Trans-Alaska Pipeline which was built and is managed by a consortium of seven oil companies holding exploration rights under the name Alyeska Pipeline Service. These companies include BP (47%), ConocoPhillips (28%), and Exxon Mobil (20%). Taking 3 years to complete, the 48-inch diameter pipeline was open for business in 1977.
800 Miles of Steel
The long steel pipeline zigzags across the frozen tundra for 800 miles. It stretches from Prudhoe Bay, on Alaska’s North Slope, to the northernmost ice-free port at Valdez, Alaska, on Prince William Sound. Along the way, it must travel over three mountain ranges, cross more than 500 rivers and streams, over three unstable earthquakes faults, and through the migration paths of the caribou and moose.
Designed to Withstand Earthquakes
The pipeline was purposely built in a zigzag configuration to allow the pipe to move more easily from side to side and lengthwise in cases of earthquakes or temperature-related fluctuations. The effectiveness of this design was proven in 2002 when the pipeline survived a 7.9 magnitude earthquake. Where it runs over fault lines, the pipeline rests on perpendicular so-called “slider supports”, long rails which will allow the pipeline to slide with the ground movement. Four hundred and twenty miles of the pipeline was built above ground because of the unstable soil conditions from the thaw sensitive permafrost and 380 miles below ground. To keep the oil flowing, there are eleven pumping stations along the length of the pipeline, each containing four pumps. Of these 44 pumps, however, only around 28 are operating at any one time.
What It Cost to Build
As one can imagine, the cost for this marvel of engineering was quite significant. The total price tag includes such items as the $2.2 Million for the archaeological survey and the $1.4 Billion for the Valdez terminal. Also included are the pump stations, 13 bridges, 225 access roads, the three “pig” launching/receiving facilities, over 100,000 lengths of 40 ft. pipe, 14 temporary airfields, and the some 70,000 salaries for the total number of employees over the life of the construction project.
The approximate cost as of 1997 to build the Alaskan Pipeline was $8 billion (does not include interest and post-1997 construction).
Don’t Melt the Permafrost
One of the most significant innovations built into the system are heat exchangers. Since the temperature of the oil flowing through the pipe can reach over 120 degrees Fahrenheit, the heat could be transferred from the pipe through the specially designed supports and could melt the permafrost. This would cause the pipeline to sink into the melted permafrost causing catastrophic damage and spillage. To prevent this scenario, heat exchangers were placed on top of the pipes. The heat is transferred from the base through pipes containing ammonia to the heat exchangers which are then is cooled by convection to the surrounding air.
Monitoring the Pipeline for Spills
Monitoring of the pipeline is accomplished by several methods. Aerial surveillance is performed several times a day, a task that can take two hours or more. Another is by sending inspection gauges, called “pigs” through the line on a regular basis which can relay radar scans and fluid measurements back to the launching facility as they travel within the line.
Although impervious to gunshots and despite the many safeguards in place, the steel pipeline is vulnerable to forest fires and terrorist attacks, domestic or otherwise. One such case in 1978 resulted in a loss of 16,000 barrels from an explosive device planted at the pipeline outside Fairbanks. Nevertheless, losses from the pipeline do occur from time to time, 1991 to 1994 being the worse when there were 164 minor spills.
The total production since June 1977 is reported to be well in excess of 500 Billion barrels. (One barrel = 42 gallons). Although the best production year was 1988 when 744,107,855 barrels of crude was shipped, since then the yearly yield has steadily declined to a low of only 270,161,990 barrels in 2007. Nevertheless, the importance of the Trans-Alaska Pipeline cannot be overstated. With nearly 40 million gallons of crude flowing through its line each day, and with more still hidden under ground, the United States can look to Alaska to provide this necessary commodity in the future.