PG&E to Test or Replace Key Pipelines

Wednesday, March 23, 2011 @ 05:03 PM gHale

Pacific Gas and Electric (PG&E) now has plans to hydrostatically pressure test or replace about 12% of its 1,805 miles of natural gas transmission pipelines in high-consequence areas, officials said.

The decision is the result of a study of pipeline records the state of California ordered following the September 9, 2010 fatal pipeline explosion in San Bruno.

The company submitted a 154-page report to the California Public Utilities Commission (PUC) on a study PG&E conducted of its records on pressure tests and records of historical operating pressure on lines in its gas transmission pipeline system.

As a result of the study, the company said it would pressure test or replace 150 miles of pipe “with records similar in vintage or other characteristics to the records” of the segment of pipe involved in the San Bruno explosion, for which they found no pressure test records.

The company was “not satisfied with the results to date,” of its search for records documenting pressure tests conducted on its pipelines and he vowed to “continue to search for and review our files for additional pressure test records,” said PG&E President Chris Johns.

It is not clear whether the company ever conducted the tests or officials could not find the results because of poor record-keeping.

On January 3, the PUC directed PG&E to “aggressively and diligently” search for all records relating to “design, construction, inspection, testing maintenance and other related records” of gas transmission lines in areas of high consequence, such as the San Bruno pipeline segment.

PG&E, in its report, was unable to produce pressure test records for 9% of pipeline segments installed after 1961 when state regulations first required such testing.

Federal regulations did not require pressure testing until 1970, before which federal regulations allowed operators to rely on historical operating pressure to establish the maximum allowable operating pressure.

Joe Molica, a PG&E spokesman, said of the 150 miles of line earmarked for testing or replacement, “most of the segments will be hydro-tested,” while certain shorter segments likely would require replacement.

He said the company does not have an estimated cost of the hydro-testing and replacement program. However, he said that, in general, PG&E estimates the cost of pressure testing ranges from $150,000 to $500,000 per mile.

The cost can vary widely, based on a number of factors such as the length of pipeline segments tested, the number of taps involved and the cost of water acquisition and disposal.

Similarly, the cost of replacing a segment of pipeline would be highly dependent on factors such as the topography of where the line is, Molica said.

PG&E has not determined whether ratepayers or by shareholders will pay for the cost of the testing and replacement program and Molica said the company would make that decision based on ongoing discussions with regulators and customers.

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