The new order amends a previous ‘corrective action’ order stipulating the actions Williams must take to restore its Northwest Pipeline’s pipeline to full service.
Northwest Pipeline received the corrective action order on 2 May following a pipeline rupture near Lake Tapps, Washington. That order directed the company to lower pressure by 20% and perform a comprehensive integrity assessment on a 429-km long segment of 26-in pipeline in the west of the state. The pipeline experienced a second rupture in the same segment on 13 December, near Toledo, Washington. While there were no injuries or property damage associated with the incident, Northwest took rapid action to idle the pipeline segment between Sumas and Washougal until the integrity on this section could be assured. Since the incident, the company has commenced an extensive inspection programme to ensure the safety and reliability of its 26-in pipeline in western Washington, and is continuing to work closely with the Office of Pipeline Safety and the Washington Utilities and Transportation Commission.
“Issues specific to this pipeline segment including environmental factors, such as soil acidity and moisture, operating conditions, age and the type of coating can play a role in creating these type of problems. We are bringing all the necessary resources to bear to ensure the integrity of our facilities and keep our commitment to operate a safe and reliable pipeline,” said Doug Whisenant, senior vice president of Williams’ gas pipeline business. “The order received today [19 December] is consistent with the inspection programme already in progress and gives us a timetable for completing the necessary work.”
The decision to idle the 26-in pipeline has had no immediate impact on the company’s ability to meet current market demand, primarily because Northwest has a parallel 30-in pipeline in the same pipeline corridor. In addition, the recent completion of the Evergreen expansion project, typical wintertime flows, and the current sourcing of gas supplies between Sumas and the Rockies mitigate the potential impact on service during this winter heating season. With the 26-in pipeline idled, capacity at the pipeline’s northernmost receipt point at Sumas is estimated to be approximately 950,000 dekatherms per day.
“As we take steps to comply with the requirement to develop a plan for replacement of this idled pipeline segment, we are evaluating alternative ways to replace that pipeline’s transportation capacity. Our preliminary analysis shows that we could replace the 376,000 dekatherms of daily capacity associated with the idled 26-in Sumas to Washougal segment with about 160km of new 36-in pipeline,” Whisenant said. “Williams has, and expects to have, adequate financial resources to comply with the order and replace the capacity, if required. Costs associated with the capacity replacement are expected to be capitalized and recoverable through future rates in a way that preserves Northwest’s ability to be competitive in its market,” he said.