When the tanker Exxon Valdez ran aground in 1989, over 240,000 barrels of crude oil were spilled into the waters of Alaska's Prince William Sound. It was the worst ever oil spill in U.S. waters. The spill, with its devastating effects on wildlife and the fishing industry, dramatically highlighted the conflicts between maintaining the energy demands of the American economy and conservation of the environment. The Exxon Valdez was only one of many tankers that carry oil from the southern end of the Alaskan pipeline to refineries on the west coast of the United States. Oil spills, such as this one, were predicted by the 1972 environmental impact statement for the Alaska pipeline prepared by the U.S. Geological Survey.
In the late 1970s the United States was importing almost half its petroleum, at a loss of billions of dollars per year to the national economy. (By 1997, the United States was importing more than half of the petroleum it uses.) This drain on the country's economy and the increasing cost of energy can be major causes of inflation, lower industrial productivity, unemployment, and the erosion of standards of living.
In the 1960s, geologists discovered oil beneath the shores of the Arctic Ocean on Alaska's North Slope. It is now the United States' largest oil field. Thanks to the Alaska pipeline, completed in 1977, Alaska has supplied as much as 20% of the United States' domestic oil.
Despite its important role in the American economy, some people consider the Alaska pipeline and the use of the tankers as unacceptable threats to the area's ecology. The 1989 oil spill demonstrated the hazards of the marine portion of the oil transportation system. Oil spilled from a ruptured pipe could have a devastating effect on the fragile Arctic plant and animal life.
Geologists with the U.S. Geological Survey conducted the official environment impact investigation of the proposed pipeline route. After an exhaustive study, they recommended against its construction, partially because of the hazards to oil tankers and partially because of the geologic hazards of the pipeline route. Their report was overruled. The Congress and the President of the United States exempted the pipeline from laws that require a favorable environmental impact statement before a major project can begin. The 1.5 to 2 million barrels of oil a day that flow from the Arctic oil fields mean that over $10 billion a year that would have been lost through the purchase of foreign oil instead remains in the American economy.
The 1,250-kilometer-long pipeline, through which 88,000 barrels of oil an hour flow, crosses regions of ice-saturated, frozen ground and major earthquake-prone mountain ranges that geologists regard as serious hazards to the structure.
Building anything on frozen ground creates problems. For example, the road was built during the exploration of Alaska's North Slope oil fields. When the road was being built, the protective vegetation was scraped off. During the summer thaw the road became a quagmire. As thawing continued, the flooded tracks shown in the photo grew into ponds so that the road will never be passable.
Building the pipeline over such terrain also presented enormous engineering problems. If the pipeline were placed on the ground, the hot oil flowing through it could melt the frozen ground. On a slope, mud could easily slide and rupture the pipeline. Careful (and costly) engineering minimized these hazards. Much of the pipeline is elevated above the ground. Radiators conduct heat out of the structure. In some places refrigeration equipment in the ground protects against melting.
Records indicate that a strong earthquake can be expected every few years in the earthquake belts crossed by the pipeline. An earthquake could rupture a pipeline-especially a conventional pipe as in the original design. However, when the Alaska pipeline was built, in several places sections were specially jointed to allow the pipe to shift as much as 6 meters without rupturing.
The original estimated cost of the pipeline was $900 million, but the final cost was $7.7 billion, making it the costliest privately financed construction project in history. The redesigning and construction that minimized the potential for an environment disaster were among the reasons for the increased costs. There have been more minor spills from the pipeline. For instance, in January 1981, 5,000 barrels of oil were lost when a valve ruptured.
Thus far, the pipeline company's claim that there is virtually no chance of a major spill from a pipeline rupture seems vindicated. However, the risks of marine transportation remain. In hindsight, a pipeline through Canada to the American Midwest might have been better in the long run (as advocated by geologists who prepared the environmental impact statement). Although longer, it would traverse less hazardous terrain, would avoid the long marine leg, and would bring the oil to refineries in the central part of the United States. A joint venture with Canada would have benefited both countries, particularly since Canada has discovered major petroleum resources in its Arctic territory.
