Will the Potrero power plant be shut down by the end of the year?

Mirant's Pittsburg power plant will outlast its Potrero power plant.

At the beginning of 2010, the official word was that an undersea high-voltage power line called the Trans Bay Cable would go live in February, supplying up to 40 percent of San Francisco's power. This was the missing piece of the puzzle that would finally lead to the shuttering of Mirant's Potrero power plant, which activists and city officials have railed against for years.

But February came and went. March, April, May, June, and July brought the same story, and the Potrero power plant kept chugging away. Good news for the roughly 30 employees who work there, bad news for nearby residents with lung problems.

August rolled around, and we decided to ask San Francisco Mayor Gavin Newsom what the deal was.

“We’re very close to making an announcement,” Newsom said at an Aug. 9 press conference, and added that he has been working closely with the head of the California Independent System Operator (Cal-ISO), Yakout Mansour, who has “made it a priority.” Then Newsom found a way to work in something about his bid for lieutenant governor. “I made it clear that I’m not leaving till it’s shut down,” he said, and reminded us that he fully intends to leave for Sacramento in January.

Why the seven-month delay? Newsom’s press secretary, Tony Winnicker, chimed in to say the setback had something to do with how the Trans Bay Cable “couldn’t carry capacity,” which didn't sound too good for a $500 million project. But project spokesperson P.J. Johnston sounded confident in a recent telephone message, saying work crews have identified the problem and corrected it. “We still believe we can go operational this year,” Johnston said.

Apparently, the delay resulted from a technical issue involving some faulty sub-module parts, which have since been replaced. “Hopefully this fix did the trick,” Johnston said.

“We’ve been doing testing since June with Siemens,” he added, referring to Siemens Power Transmission & Distribution, Inc., a partner in the project development. “We started a second round of testing here in August, and we should be doing so for several weeks, well into September.”

If the Trans Bay Cable goes live before the end of 2010 and the Cal-ISO finally releases the Potrero power plant from a requirement that says it “must run,” the result will be an improvement in air quality in San Francisco – particularly for residents in Dogpatch and Bayview Hunter’s Point neighborhoods.

However, the Trans Bay Cable will ultimately be bringing in power from somewhere else, and for now, the bulk of that electricity will still be generated by fossil fuels. The other end of the 53-mile, high-voltage undersea cable will connect to power sources in the city of Pittsburg. Mirant operates two major electricity generation units there -- one is 50 years old and the other is 38 years old -- for a total capacity of 1,311 megawatts. It sells the power to Pacific Gas & Electric Co. PG&E is seeking state approval to build two more power plants in Antioch and Oakley, located a bit further east of Pittsburg in Contra Costa County.

A report by Pacific Environment explores the potential health impacts of PG&E’s proposed power plants, highlighting the toxic landmarks that already mar the air quality in that area.

“Contra Costa County already contains more than its share of polluting industries,” Pacific Environment notes, “including over a dozen power plants, five oil refineries, several chemical plants, and many other industrial facilities. Due to the volume of pollution already located in Eastern Contra Costa, the increased emissions from these two new power plants are likely to exacerbate already-high rates of respiratory and other diseases. The report also concludes that PG&E does not need the power plants, as the utility already has more than 30 percent of the power needed in ‘peak’ conditions.”

Maybe Newsom will boast someday about being the San Francisco mayor who worked with the Cal-ISO to shut down the Potrero power plant. But at the state level, a sustainable solution is one that would leave residents of Pittsburg, Antioch, and Oakley breathing easier too.