 Joint Pipeline Office Photo PERMAFROST THAW AREA-- The trans-Alaska oil Pipeline traverses the Squirrel Creek area near Copper Center last summer. |
Scientist: Warming climate may affect pipeline stability. By Sean Cockerham Staff Writer An expert in global climate change stepped to the microphone in front of U.S. Sen. Ted Stevens and delivered a warning. "Continued warming is expected to result in the thawing of the top 30 feet of discontinuous permafrost during the next 100 years-- |
| which would result in much greater impacts than those currently being experienced," said Dr. Margaret Leinen of the National Science Foundation. The example that Leinen offered was the hefty expense of replacing supports for the trans-Alaska oil pipeline. She was not the only person to raise the matter this week during Stevens' climate change hearings at the University of Alaska Fairbanks. The Alaska Forum for Environmental Responsibility sent Alaska's senior senator a letter of concern."This is a huge issue of the pipeline's structural integrity," said Ross Coen, the Fairbanks-based executive director of the organization. "As climate change continues to affect the Alaska environment, how can we be sure that an already serious problem with the (supports) won't get worse?" But both Alyeska Pipeline Service Co. and the Joint Pipeline Office--a consortium of state and federal regulators-- say the matter is being scrutinized and there is not a basis for safety worries. "I would not say this is a concern at all," said JPO spokeswoman Rhea DoBosh, who said that JPO has closely monitored the issue and has plans for continued oversight. "For several years it has been apparent that some of the Vertical Support Members have been leaning a little bit and some (ground) conditions have changed. Alyeska has quite an aggressive program to study them and determine which ones need to be replaced," she said. Some 78,000 H-shaped Vertical Support Members are located along the 420 above-ground miles of the trans-Alaska pipeline. The Joint Pipeline Office reports that about 25,000 of them may have shifted to some extent, but said there is not enough movement associated with the majority of them to justify concern. Elden Johnson, who handles system integrity in the Fairbanks office of Alyeska Pipeline Service Co., said Alyeska has identified about 250 VSM's that are candidates for major maintenance or replacement. "We would have to have movements on the order of at least, say three to six inches, before we start to have maintenance concerns," he said, adding that other factors including location also play a role. Johnson said the replacement cost for each VSM is about $85,000. The 250 number is the "upper limit" that he figures would need to be replaced over the next decade.Global warming is a matter of debate. Should the National Science Foundation's forecasted level of permafrost thawing come true, then additional VSM maintenance could well be required, Johnson conceded "I feel our monitoring program would pick those situations up and allow us to maintain the pipeline," he said.Last year Alyeska replaced VSMs in the Squirrel Creek area south of Copper Center because of thawingpermafrost. The area is particularly susceptible to thaw, Johnson said, and lies on the southern margin of permafrost. "It became a maintenance headache," Johnson said. "So we determined that given the maintenance history it was cheaper and better to go in and replace 18 VSMs." Coen, of the Alaska Forum For Environmental Responsibility, fears the oil companies that own Alyeska will balk at the price of full VSM replacement if more are needed because of warming temperatures.The application to renew the pipeline right-of-way for the next 30 years should contain a commitment by the companies to pay, and a detail of Alyeska's plans to deal with the matter, Coen said. But DoBosh of the Joint Pipeline Office said the matter is under an ongoing oversight program that need not be specifically detailed in the application. When the pipeline was constructed it was foreseen that there would be soil changes over time and the need for VSM maintenance, she said. "It's not something that just popped up out of the blue," DoBosh said. A recent JPO report did cite a "potential threat" to VSM supports. A combination of a warming climate and potentially reduced performance of the pipeline's permafrost-protecting heat pipes due to existing blockages could jack up supports, the report said. But DoBosh said JPO is satisfied that Alyeska's monitoring program would detect any situation before it became a problem. "It won't happen overnight," she said. | |