By Donna Beth Weilenman
Staff Reporter

When Tesoro Corporation’s Golden Eagle Martinez plant lost its power source Wednesday, the result was billowing black smoke and towering flames as the plant burned off the products it was processing.

Valero Benicia Refinery, on the other hand, doesn’t depend on outside sources for most of its power.

“The refinery has electrical power generation facilities that produce enough electricity to meet about 90 percent of our regular operating needs,” Sue Fisher Jones, the refinery’s media executive director, said Thursday. “In other words, we operate almost entirely ‘off the grid’ most of the time.”

The remaining amount of electricity is supplied by PG&E, Fisher Jones said.

The Tesoro refinery’s power loss caused it to use flaring in multiple stacks to handle its products. While that process is visually dramatic, it’s actually a safety feature that burns off gases that otherwise would build up pressure and explode.

The Martinez plant operated according to plan in the emergency, officials have said.

The power shortage itself, which impacted thousands of residents and businesses and included all of Concord, is still under investigation.

The Tesoro refinery, which was shut down Wednesday afternoon as residents were warned to shelter in place, began its restart Thursday.

Even though PG&E supplies only a small part of the energy Valero Benicia Refinery uses, should that power be lost emergency plans are in place for the plant to begin shedding noncritical electrical loads, Fisher Jones said.

“This could include reduction in lighting, shutdown of building heating and air conditioning, or other noncritical uses,” she said.

“By reducing our internal demand, we would be able to continue operating on our own internally produced power.”

In addition, she said, steam-driven equipment would continue to operate in place of an electric motor during a power outage.

“Critical refinery controls systems are also supplied with back-up battery power,” Fisher Jones said, explaining that such systems are an uninterruptable power supply — “so equipment can be shut down safely if necessary.”

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