Sempra Energy's Southern California Gas Co. (SoCalGas) said its methane gas capture system has conserved more than 2.5 MMcf of natural gas since first being deployed in August 2016, which on average is enough gas to fuel more than 12,500 American homes for a day.

SoCalGas said the methane capture system was one of the best practices included in the utility's Leak Abatement Compliance Plan approved earlier this month by the California Public Utilities Commission (CPUC).

"For more than 25 years, SoCalGas has been working hard to reduce emissions from its operations, and because of many practices, like the gas capture system, we have one of the lowest methane emission rates of any natural gas distribution company in the country," said SoCalGas' David Buczkowski, vice president of gas engineering and system integrity. He added that management believes the plan approved by CPUC "will assist our efforts to further reduce emissions."

The methane capture system was developed through Sempra's Pipeline Safety Enhancement Plan (PSEP) mandated five years ago by state regulators following the tragic San Bruno gas pipeline explosion in Northern California eight years ago, which killed eight people. PSEP identifies various high pressure pipeline sections throughout the utility's system and schedules them to be pressure-tested or replaced.

According to SoCalGas, the system includes a fiber optic cable network, infrared cameras and sensors, aerial leak surveys from aircraft and drones, in-line inspection tools and external corrosion surveying. It also includes algorithms to identify unusual levels of natural gas consumption.

The utility said it is continuing efforts to expand renewable natural gas (RNG) production and use in California. It cited a study commissioned last August by Navigant Consulting Inc. that found replacing about 16% of the traditional gas supply with RNG can achieve greenhouse gas emission reductions equivalent to converting 100% of the buildings to electric-only energy by 2030.

SoCalGas began introducing biomethane into its pipeline system earlier this year sourced from places such as dairies, wastewater treatment plants and landfills. Last July, the utility began collaborating on RNG research with Quebec-based Énergir, a gas distribution utility, and France's GRDF and GRTza, which are gas transmission network managers.