California regulators on Thursday approved a $314 million methane emissions mitigation program for natural gas utilities, with the bulk of the funds allocated to Sempra Energy's Southern California Gas Co. (SoCalGas).

The California Public Utilities Commission (CPUC) unanimously approved individual two-year utility compliance plans from SoCalGas for $234 million, Pacific Gas and Electric Co. (PG&E) for $66 million, San Diego Gas and Electric Co. for $12.3 million, and Southwest Gas Corp. for $2.4 million.

"Reducing methane emissions by repairing or replacing pipes and associated infrastructure advances both policy goals for natural gas pipeline safety/integrity and reduces greenhouse gas emissions," the CPUC stated.

The five-member CPUC approved each utility's proposed plan mostly as they were submitted, except for PG&E’s, whose plan dollar amounts authorized for rates was cut in half. The CPUC cited "excessive costs" for the repair of the combination utility's backlog of nonhazardous, small leaks.

A SoCalGas spokesperson said the utility intended to continue applying new technologies for "one of the tightest gas systems in the country." In addition, because 80% of the state's methane emissions are from agriculture and waste industries, "SoCalGas will continue to work to expand the production and use of renewable natural gas."

Last year California's air pollution regulators adopted some of the toughest methane standards in the nation, drawing praise from the Environmental Defense Fund and other groups that have been critical of state efforts, particularly after the four-month leak at the well in the Aliso Canyon underground gas storage field north of Los Angeles.

The utilities submitted proposed pilot and research/development (R&D) programs, which would be monitored by the CPUC's Safety and Enforcement Division (SED). SED plans to conduct regular progress reviews at least every six months, with the first one due at the end of this year.

"Each utility shall submit a written evaluation of the results of each pilot and R&D project prior to submitting the next compliance plan” for beyond 2020, the CPUC resolution noted.

Mandated by a 2015 state law aimed at minimizing natural gas leaks statewide, the CPUC worked with the California Air Resources Board and others to develop a set of criteria and best practices for identifying, measuring and stopping leaks in the state's gas pipeline network. Last year, 26 best practices were articulated, and SED established a standardized template for compliance plans before each utility was authorized to develop their individual plans.

EDF's California senior director Timothy O'Connor called the plans "sweeping" and a fundamental game changer. "This is a massive deal. After years in development, California utilities are finally accountable for reducing the negative environmental impact that gas leakage can cause."

O'Connor said California's gas pipeline network emits more than 100,000 metric tons of methane each year. The collective plans are expected to reduce overall methane emissions in 2030 by 40%.

"The CPUC has approved sweeping new plans to radically change how gas utilities will deal with intentional and unintentional leaks in their pipelines," said EDF spokesperson Kelsey Robinson, who noted that the program focuses on both leaks posing safety hazards and ones that are low-risk but pose climate threats.