Pacific Gas & Electric Co. (PG&E) will use a fleet of high-tech vehicle-mounted methane detectors in conjunction with on-foot patrols during a yearlong survey of its gas distribution pipeline system.
As part of PG&E’s ongoing commitment to provide customers with safe, reliable natural gas service, the company conducts comprehensive surveys of its gas distribution pipeline system. This year, PG&E will survey 1.2 million customer service lines, customer gas meters and corresponding distribution pipeline.
PG&E’s leak survey program covers the entire extended 42,000-mile distribution system on a three-year cycle under the company’s accelerated inspection program, compared to the five-year cycle that is mandated by law. Distribution lines carry natural gas from the high-pressure transmission pipelines into communities at a reduced pressure. These lines feed service lines that connect directly to natural gas meters. PG&E also surveys its entire high-pressure transmission pipeline system twice per year.
“Over the course of this year, our crews will cover thousands of miles as they carefully survey the system,” said Joe Forline, PG&E gas operations senior vice president, in a Feb. 3 company statement. “They will be equipped with technologies that are so precise, we are able to detect even the smallest molecule of methane. This proactive assessment is part of our comprehensive commitment to operate a safe, reliable, and environmentally focused system that provides customers with natural gas 365 days a year.”
PG&E will employ two methods to conduct these inspections, mobile patrols and traditional foot patrols.
Mobile patrols use state-of-the-art vehicle-mounted Picarro Surveyor. This highly sensitive leak detection technology measures methane plumes in the air, maps the location, and prioritizes the leak by its grade within PG&E’s system. To conduct inspections using this method, a vehicle equipped with the methane sensors drives through a neighborhood measuring the air and methane in parts per billion, allowing the sensors to identify and pinpoint the exact location of the methane source.
Traditional on-foot patrols conducted by PG&E personnel and contractors use advanced hand-held methane detection devices. This year, PG&E has deployed new hand-held leak detection devices that surveyors will use when they inspect service lines and customer meters. For gas meters that are in inaccessible areas, customers will be asked to provide access. Access to inspect all meters is critical to the safe operation of PG&E’s gas system. When these inspections are being conducted, customers will see PG&E employees or contractors, and both will have company-issued identification badges which they will present upon customer request. PG&E contractors will not be operating PG&E-marked vehicles, and customers can ask to see identification to confirm their identity.
When leaks are identified on gas distribution systems, utilities including PG&E, they are assigned a grade based on a national scale. If leaks are assigned as “grade one,” PG&E will make immediate repairs. As part of its ongoing efforts to curb emissions from its system, PG&E also prioritizes repairs for the highest emitting leaks.Tags: Leak Detection, methane emissions, PGandE