Like its counterparts in Northern California, San Diego-based Sempra Energy's two utilities operating the intrastate natural gas transmission pipeline system in the southern half of the state face the prospect of additional hydrostatic pressure testing on several hundred miles of transmission pipeline for which the company cannot verify past testing to support current operating pressures.
While Southern California Gas Co. and San Diego Gas and Electric Co. officials said since an April 15 report to the California Public Utilities Commission (CPUC) more verification has been obtained and operating pressures have been reduced on some pipelines, the head of the CPUC Consumer Protection and Safety Division (CPSD) informed the utilities last Tuesday that additional pressure testing may be required.
Noting the safety staff's assessment should not be considered a decision by the five-member CPUC, nevertheless the CPSD feedback from Richard Clark, CPSD director, pointed toward recommending the regulators eventually require more testing.
As a result of the identification and verification requirements placed on Pacific Gas and Electric Co. (PG&E) in the wake of the San Bruno transmission pipeline rupture last September, the CPUC is asking Sempra utilities to do the same (see Daily GPI, April 19) regarding the safety validation for the maximum allowable operating pressure (MAOP) of each pipeline segment passing through high-consequence, or heavily populated, areas.
Using National Transportation Safety Board (NTSB) criteria recommended after the San Bruno explosion, the CPUC wants pipeline operators to pressure test or replace any segments for which there is no "traceable, verifiable and complete records" supporting the current MAOP.
The CPUC safety staff thinks that most of the pipelines in Sempra's Category 1 and 2 lines meet the NTSB criteria; however, for lines in Category 3 and 4, Clark raised doubts in his letter. He said CPUC staff does not think there can be any substitute for hydrostatic testing or replacement for the segments unable to meet the federal criteria.
As he has done with PG&E, Clark told Sempra's utilities that the regulatory staff recognizes that the testing or replacement is both costly and disruptive to the utility transmission pipeline operations, and thus, "time and flexibility" need to be allowed to get the job done.
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