In the hot seat since the Sept. 9 rupture of one of its natural gas transmission pipelines, Pacific Gas and Electric Co. (PG&E) sent a nine-member engineering team to the three-day National Transportation Safety Board (NTSB) hearings, which began Tuesday in Washington, DC.
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Saying it has limited operational flexibility to manage imbalances in zones 0, L, 1 and 2, and due to the force majeure at Station 214 in Ohio resulting from a potential pipe rupture Thursday night, Tennessee issued an Imbalance Warning Monday requiring all delivery point operators in those zones to keep actual daily takes out of the system equal to or greater than scheduled quantities regardless of their cumulative imbalance position. Similarly, all receipt point operators in the zones were asked to keep actual daily receipts into the system equal to or less than scheduled quantities regardless of their cumulative imbalance position.
Tennessee declared a force majeure event Friday for Station 214 (Carrolton, OH) after a “possible rupture” occurred nearby (see related story). No injuries were reported, and there was no interruption of customer service, said pipeline spokesman Robert Newberry. However, Tennessee anticipated limiting intraday flow increases for Friday’s gas day and restricting 100% secondary out of path (SOP) nominations and lower priority services going forward, with a possibility of restricting a pro-rata portion of secondary in path (SIP) nominations. “At this time the certainty of such restrictions [is] unknown due to the current investigation of the incident,” a bulletin board posting said.
The National Transportation Safety Board (NTSB) issued another preliminary report Tuesday on the deadly San Bruno, CA, natural gas transmission pipeline rupture last September, eliminating external corrosion, excavation damage or a pre-existing leak as possible causes.
The explosion and fire that shut down the DCP Midstream East Texas gas processing plant north of Carthage, TX, Wednesday was caused by the rupture of a third-party pipeline outside the company’s property, DCP Midstream said Thursday.
As previously posted (see Daily GPI, Aug. 13), Southern Natural Gas has been performing inspections on the 26-inch diameter line downstream of Gate 6 (where a rupture occurred recently in a 20-inch diameter line) and installing an interim solution at Gate 6 to allow Main Pass area volumes to flow into the 26-inch line. The interim solution at Gate 6 and the anomaly inspection on the 26-inch line have been completed, Southern said, and effective with the Intraday 2 nominations cycle Tuesday and until further notice it is allowing about 650,000 Dth/d to flow into the 26-inch line. See the bulletin board for a list of affected points.
A nonaffiliated worker was killed when ANR experienced a pipe rupture about 10 a.m. EST Tuesday in Cass County, MI. The blast occurred on a 24-inch diameter tie line connecting the Bridgman, La Grange and Defiance compressor stations, said a spokesman for ANR parent firm El Paso Corp. There was no fire, but an employee of Midwest Energy Cooperative who was doing work in the vicinity was fatally injured, he added. An investigation is under way. There was no service impact.
Citing welding delays in repairing a Saturday rupture west of Cheyenne Station (see Daily GPI, Nov. 14), Wyoming Interstate Co. said it was required to maintain a curtailment of mainline capacity through its Laramie East constraint point to zero through at least Wednesday. Flow through the Medicine Bow Lateral was not impacted, WIC said. “At this time, WIC anticipates that it will be able to accept nominations…Wednesday for its full Wyoming mainline capacity” in the Timely cycle for Thursday’s gas day, the pipeline said.
There were no injuries or fire when a rupture occurred early Thursday morning on Tennessee’s 30-inch diameter line near the town of Halfway in Allen County, KY, about 70 miles north of Nashville, TN. Up to 200 residents in the area were evacuated temporarily but had returned to their homes shortly after daybreak Thursday, a pipeline spokesman said. The affected section was closed off quickly, and no services were interrupted, he added.