Sempra Energy’s Southern California Gas Co. (SoCalGas) reached a milestone in methane capture technology during natural gas pipeline replacement operations, according to the Los Angeles-based natural gas utility.
Under advanced processes undergoing pilot tests, SoCalGas said it has captured more than 1 MMcf of methane during pipeline replacement work and reinjected the captured gas into its transmission/distribution pipeline system.
In routine pipeline operations, crews are required to purge the line of natural gas, so by capturing it, SoCalGas is reducing carbon emissions, albeit relatively small amounts in the larger universe of greenhouse gas (GHG) emissions. SoCalGas compressed most of the compressed natural gas (CNG) and pumped it into large tanks to be put back into the system for customer use.
SoCalGas crews in August completed 11 hours of work near the Sepulveda Dam in Los Angeles, capturing about 260,500 cf from a transmission pipeline that was removed from service as part of a pipeline replacement initiative, which pushed the utility over the 1 MMcf benchmark.
Last year, SoCalGas engineers said they first successfully tested a methane capture system on a 2.5-mile distribution pipeline replacement project. Using CNG, the capture and reuse test was accomplished as part of the utility’s Pipeline Safety Enhancement Plan (PSEP) mandated five years ago by state regulators after the San Bruno, CA, transmission pipeline explosion.
Utility officials noted that PSEP also includes provisions to upgrade, replace or retrofit hundreds of mainline valves using technology to remotely operate the system and automatically shut off the flow of gas in the event of a large drop in pressure.
"SoCalGas dedicates significant resources to improving the safety and integrity of its more than 101,000 miles of natural gas pipelines," a spokesperson said. This year, SoCalGas plans to spend about $1.2 billion for improvements to distribution, transmission and storage systems and for pipeline safety.
While emissions from gas distribution systems represent less than 1% of GHG emissions nationwide, SoCalGas’ Rick Phillips, senior director of PSEP, said the utility is "making every effort" to help reduce emissions as much as possible. "We are committed to making investments to meet California’s ambitious environmental goals and using this methane capture technology when possible is just one way we are achieving these goals.”