Safety, RNG are hot topics in Calif. gas utility sector

California natural gas utilities are moving toward a lower-carbon future by expanding into renewable natural gas, but the industry's past safety lapses continue to weigh on their operations.

The utilities asked that the state clarify and tweak its implementation of federal pipeline safety recommendations tied to a 2018 gas distribution system catastrophe in Massachusetts.

The federal recommendations would require professional engineers to approve gas system construction and design plans. PG&E Corp., Sempra and Southwest Gas Holdings Inc. subsidiaries advised limiting the requirement to higher-risk and more complex design work during a Jan. 13 workshop hosted by the California Public Utilities Commission, or CPUC.

The recommendation stemmed from the 2018 Merrimack Valley disaster on a former NiSource Inc. subsidiary's distribution system in northeastern Massachusetts. A pipeline overpressurization event that was traced to deficient project planning led to a series of deadly and destructive fires and explosions across three communities. The U.S. National Transportation Safety Board found that the employee who approved the work plans was not fully licensed as a professional engineer. More experienced supervisors did not closely review the plans, the board found.

The safety culture at Sempra and subsidiary Southern California Gas Co. also came under the microscope in a recent independent review, which identified several critical areas for improvement. The companies have a narrow concept of safety and do not take a systemic approach to identifying and managing risk, according to a Dec. 10, 2021, report by Evolving Energy Consortium, or 2EC. While the consultancy found some signs of a healthy safety culture, "overall SoCalGas is highly 'siloed,'" 2EC found. "For example, risk and safety are conceptually and functionally separated, and departmental segmentation occurs around types of risks."

"But even more generally, information sharing, coordination of activities and learning do not often occur across levels and divisions," 2EC said.

The report arose from an inquiry opened by the CPUC into whether the safety culture at Sempra and SoCalGas contributed to recent incidents, including a massive and prolonged gas leak from the Aliso Canyon natural gas storage facility (19-06-014). The report's release marked the start of the second phase of the proceeding, which was delayed by the COVID-19 pandemic.

As the utilities dealt with these issues, the sector moved further into renewable natural gas, or RNG. PG&E subsidiary Pacific Gas and Electric Co. started accepting RNG from 15 dairy farms in Merced County, Calif., into its transmission system.

Pacific Gas and Electric, in partnership with Maas Energy Works Inc. and the California Energy Exchange, began flowing RNG into the utility's gas transmission system in mid-December 2021, according to a Jan. 13 news release. The project relied on funding from a CPUC-backed program — the Dairy Biomethane Pilot Program — geared toward curbing short-lived but potent greenhouse gases. The project involves gas production and cleaning equipment and interconnection facilities to move RNG from farms into the California Energy Exchange and Pacific Gas and Electric transmission pipelines.