GRASS VALLEY, Calif. — As part of Pacific Gas and Electric Company’s commitment to providing customers with safe and reliable energy, PG&E has embarked on a six-month project to modernize a section of natural gas transmission pipeline running from east Wheatland to west Grass Valley. The modifications will enable In-Line Inspections (ILI) with a state-of-the-art pipeline inspection gauge (PIG).
PG&E will be excavating portions of the pipeline at 13 locations to refine angles within the line so that the special inspection tool dubbed a robotic “pig” can travel inside the length of the 27-mile pipeline. The robotic tool uses probes and sensors to study the pipeline from the inside. The tool is looking for anomalies including dents or corrosion.
The majority of excavations will be taking place along Spenceville Road between Indian Springs Road and Highway 20 in Penn Valley.
“This In-Line-Inspection technology is PG&E’s preferred method of inspecting our natural gas pipelines,” said Joe Wilson, regional vice president for PG&E’s North Valley & Sierra Region. “It helps us validate that the pipeline is in safe and compliant operating condition. Identifying these issues quickly and efficiently helps keep our communities safe.”
The inspection tool will enter the pipeline at a portal with above-ground pipes at a fenced launcher facility in northeast Wheatland. PG&E will also expand this launcher facility.
The receiver site, where the tool is taken out of the line, is located off Squirrel Creek Road in west Grass Valley near the middle of four private parcels. This facility will also be fenced and only occasional visited by crews for inspections and maintenance.
While PG&E is working on the 6 and 8-inch diameter pipeline, portions of it will be void of gas. To keep customers supplied with gas, PG&E will use portable compressed natural gas (CNG) and inject the gas into the pipeline downstream of the work areas.
PG&E is also building an injection port for the CNG or liquified natural gas at the northwest corner of Adam Avenue and Rough and Ready Highway in Grass Valley. While work on the gas transmission line is occurring, PG&E will keep gas flowing to customers in Grass Valley by injecting portable natural gas.
Once work on the line is completed, the site will have very little activity going forward except for maintenance or if gas again needs to be injected at the location.
PG&E is notifying customers near work sites by letter and outbound automated phone calls. The entire project should be completed in the before fall. Weather and other factors that affect safe working conditions may change the schedule.
PG&E regularly inspects pipelines to proactively ensure the safety and reliability of its gas system. PG&E has also strength-tested and replaced pipelines, adding remote-control and automatic shut-off valves that can stop the flow of gas faster in an emergency, and checking for leaks on a strict schedule.