Vessel Traffic Overview
Updated:October 9, 2009 14:51
Tanker and Tank Barge Vessel Traffic in the Aleutians Subarea
Tankers and tank barges towed by tugs do transit the Aleutians Subarea. Tugs and tank barges transport non-persistent oil into the subarea for fuel and heating oil. Non-persistent oil and persistent oil are transported through the subarea to other destinations.
Non-persistent Oil Transported by Tank Vessels with State Contingency Plans
Figure 9 shows the routes by which fuel and heating oil is delivered to the communities of the Aleutian Islands and western Alaska by tank barges pulled by ocean-going tugs. The tugs and barges transit from refineries at Nikiski in Cook Inlet, Valdez in Prince William Sound, and Puget Sound to the various bulk fuel facilities throughout the Aleutians Subarea. Most deliveries to bulk fuel facilities in the Bristol Bay, Western Alaska, Northwest Arctic, and North Slope subareas also transit the Aleutians Subarea. Figure 9 also shows the route of the tanker that delivers fuel and heating oil to Adak and Dutch Harbor from Russia.
Two documents provide information on the volume of oil delivered to or transported through the Aleutians Subarea:
- Study of Noncrude Tank Vessels and Barges completed in July 1991 by Arthur D. Little (A. D. Little) for the ADEC, and
- Agreement for Compliance for Tank Barge Transport of Non-persistent Oil in Alaska revised in 2003 by the Alaska Petroleum Distributors and Transporters (APDT).
The A. D. Little Study indicates that about 385 million gallons of non-persistent oil either stays in the region or passes through to other Alaskan destinations. However, the report does not provide any data on the number of voyages.
The APDT Agreement also has information on the amount of non-persistent oil transported into and through the Aleutians Subarea. Table 4 summarizes the oil transfers and transits by subarea. Interpreting this table is difficult because of the ranges, but using the median of the ranges yields an estimate of 300 million gallons of non-persistent oil per year delivered in 135 voyages to all of the subareas. Looking at just the Aleutians Subarea, the estimate is 150 million gallons of non-persistent oil delivered in 40 voyages.Interviews with the two largest tank barge companies providing non-persistent oil products provide another source of information. The companies were asked about the size of their tank barges and the average number of trips that they make into the Aleutians Subarea each year. Together they estimated that they transport 36 to 43 barge loads of non-persistent oil through the subarea. Taking the median of the ranges would yield an estimate of 147 million gallons of non-persistent oil per year moved in about 41 voyages.
The port call data provided in Table 3 also indicates that four tanker calls were made to Dutch Harbor by a tank vessel in 2004. Coast Guard records for January 2005 through July 15, 2006 show this tanker making seven calls at Dutch Harbor. The T/V Renda is a 1.6 million gallon capacity tanker that is known to bring non-persistent oil to Adak and Dutch Harbor from the Sakhalin Islands in Russia. Other smaller tank vessels also have approved contingency plans for the Aleutians Subarea and may trade there in the future.
About 150 million gallons per year of non-persistent oil moves into the Aleutians Subarea for fuel and heating oil in about 40 to 50 voyages and another 150 to 200 million gallons per year of non-persistent oil moves through the Aleutians Subarea to provide fuel for other western Alaskan destinations. All of these oil movements are covered under State Oil Discharge Prevention and Contingency Plans.
Oil Transported through the Aleutians Subarea by Tank Vessels without State Contingency PlansThe US Department of Commerce oil export permit regulations prohibit tankers delivering and returning from delivery of Alaska North Slope Crude Oil from transiting the Aleutians Subarea. However, oil imported or exported from Cook Inlet is not banned from the North Pacific great circle route. Tesoro Alaska indicated that they discourage their chartered tank vessels from using the North Pacific great circle route, but they do not prohibit it. In fact, the AIS receiver at Unimak Pass detected no tank ships coming from Cook Inlet.
From October 2005 through June 2006 the Unimak Pass AIS receiver detected five tankers (classified as crude oil carriers) and eight product tanker transits. All but one were proceeding west from North America. At least one of the crude oil tankers was in “ballast” and thus did not have oil cargo aboard. We assume that the crude oil tankers, based on destination and origin, were carrying heavy residual refined product and that the product tankers were carrying lighter refined products. If this traffic pattern is typical for the entire year, then approximately 15 refined product tankers pass through the Aleutians on great circle voyages annually, transporting about 180 million gallons of non-persistent oil products. Also there are approximately 7 crude oil tankers passing through the Aleutians on great circle voyages annually, transporting about 225 million gallons of persistent oil products. However, this analysis does not take into consideration that some of the tankers may be in ballast.
