PG&E using 'pig' technology to test pipelines

(KGO)
July 9, 2012 5:25:32 PM PDT
PG&E is showing off new "pig" technology that it will deploy starting Friday to check Bay Area gas pipelines for defects.

Public safety is the overriding goal in having new and better testing, but even new technology doesn't mean fast results. It would take an analyst two months in Texas to analyze all the data that would be collected in a single segment, yet that's more information than PG&E currently has for its 5,700-mile gas transmission network.

Engineers like to call the new devices "MRIs" for pipelines. Some can travel through pipes from 24 to 31 inches in diameter. Some smaller ones are designed for six-inch pipes. They are propelled by the gas pressure in the pipe, up to 11 miles an hour for the small ones and up to five miles an hour for the large ones. That means the gas lines don't have to be shut down during testing.

It's technology leased from a joint venture called Pii Pipeline Solutions. "These brushes induce the magnetism into the pipe wall and it creates a circuit. So, if you have good pipe wall, the circuit continues, but if you have a corrosion defect, what happens is the circuit is broken. You have magnetic flux leakage. Hence, the technology's name," explained Erick Quick with Pii Pipeline Solutions.

The next section detects welds, followed by a batter, and memory. Twin odometers at the tail track precise locations to let repair crews know where to dig later. PG&E will start pigging a 15-mile gas line on Friday running from Fremont to San Lorenzo at a cost of $1.5 million. Some pipelines will be difficult to pig due to bends or valves that block passage.

"Over time, those facility modifications, as we make launchers and receivers, require expenses, and that is a discussion that will be had with the CPUC in terms of how ultimately those modifications and improvements get paid for," said PG&E Transmission and Operations VP Jesus Soto Jr. PG&E is working closely with local fire agencies. Milpitas Fire Chief Brian Sturdivant said he welcomes this new technology, but he's measured in whether he thinks it will lead to greater safety and confidence. "As we know with any level of technology, we definitely need to take the baby steps and we need to insure that the data is analyzed correctly," he said.

PG&E will spend $10 million to scan 206 miles of pipeline this year, yet that's only a fraction of the 1,200 miles of pigable pipeline in the PG&E pipeline network.


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