Power outage causes flaring at Nipomo Mesa oil refinery

The flare at Phillips 66's Nipomo Mesa refinery Tuesday, May 20, as seen from Highway 1 just south of Willow Road.
The flare at Phillips 66's Nipomo Mesa refinery Tuesday, May 20, as seen from Highway 1 just south of Willow Road.

Flaring could be seen Tuesday morning at the Phillips 66 Santa Maria refinery on the Nipomo Mesa as a result of a power outage at the facility.

The power outage happened at 5 a.m. and caused an unscheduled shutdown to the refinery, spokesman Dennis Nuss said in an email. No injuries were reported.

As a result, fuel gas was directed to the refinery’s flare. About 8:30 a.m., a Nipomo Mesa resident sent a photo to The Tribune, showing a flame burning on top of the refinery’s flare stack.

PG&E spokesman Blair Jones said the outage lasted about 90 minutes. The transmission lines involved only feed the refinery, he said, so no other customers were affected. The cause is still under investigation.

“The refinery does have backup generators for key equipment but not for the entire system,” Nuss wrote in an email. “Refinery personnel are working to restart the facility in a safe and timely manner.”

Nuss said that Phillips 66 is required to notify various regulatory agencies, including the San Luis Obispo County Air Pollution Control District, California Office of Emergency Services, the National Response Center, the Cal Fire station on the Mesa and the county’s environmental health department.

Phillips 66 employees are monitoring air quality off-site and have not reported any impacts, he said.

The power outage comes nearly three weeks after an unscheduled shutdown of a unit at the refinery led to a flaring event. Some county residents took photos of black smoke billowing from the flare.

In that incident, the company said its steam power plant — which powers compressors and other equipment in the refinery — shut down for about two hours.

According to a preliminary report sent to the county air district on the incident, a cooling fan on one of the refinery’s three utility steam boilers malfunctioned, dropping the boiler offline.

The refinery needs two working boilers to maintain normal operations, and a third boiler already had been pulled off for routine maintenance, leaving only one, said Aeron Arlin-Genet, manager of planning and outreach for the air board.

As a result of the boiler shutdown, fuel gas was directed to the flare, which Nuss said is an important safety device that safely burns gases during an emergency, such as an equipment breakdown or power outage.

Whenever such an emergency “impacts operating conditions in a way that results in the pressure in the refinery equipment to rise, valves automatically open to divert the gases to the flare to safely burn these gases that could otherwise pose potential risks to workers, the community or the environment,” Nuss wrote in a recent email.

He added: “Flares are also used to ensure safety during the startup and shutdown of refinery equipment when gases generated by those processes cannot be safely recycled into the refinery.”

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