Why does the Potrero power plant operate with an expired water permit?


By Rebecca Bowe

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On Dec. 31, 2008, Mirant’s wastewater-discharge permit expired -- but the gas and diesel-fired power plant still runs an average of nearly 20 hours a day, according to figures released by the California Independent System Operator (Cal-ISO).

One unit at the facility uses a system called once-through cooling, which means it takes in huge quantities of water from the bay to cool the machinery, then dumps it all back at temperatures high enough to impact surrounding ecosystems. This process is regulated by a permit issued by the San Francisco Bay Regional Water Quality Control Board. A spreadsheet on the agency’s Web site shows that more than five months into 2009, a hearing to outline the terms of a new wastewater-discharge permit still hasn't been scheduled. The water board is waiting on a state policy decision regarding once-through cooling before it acts, a note explains.

According to Deputy City Attorney Theresa Mueller, who is familiar with the matter, the Mirant Potrero facility is operating on something called an “administrative extension” in the interim. Unlike an average person who would face serious consequences for driving around with an expired driver’s license, Mirant is apparently allowed to keep chugging along on an expired wastewater permit for as long as it has it takes the water board to get around to reissuing one. It only needs to apply for the extension on time. According to Mueller, “Mirant has operated for many years in the past under administrative extensions.”

For activists and elected officials who have been trying to shutter the plant for years, a central question is whether it would continue operating in the event that the water permit was denied. As things stand, the plant is required by the Cal-ISO to keep running in order to satisfy electricity reliability needs. Would that “reliability must run” requirement remain in effect even if Mirant lost its water permit? In Mueller’s opinion, it wouldn't. “The ISO’s must-run contract does not trump any state permitting agency or environmental regulations," she told us. "The ISO cannot force [Mirant] to run out of compliance.” Furthermore, she said, the water board has the power to either reissue or deny the permit at any time, with or without the state policy decision. But nearly everyone we spoke with for this story expressed doubt that the water board would do anything besides stick to the status quo. Multiple phone calls to the agency for comment were not returned.