Mirant’s last gasp?

Pub date May 6, 2009
WriterRebecca Bowe
SectionGreen CitySectionNews & Opinion


GREEN CITY A new multipronged effort to shut down San Francisco’s Mirant Potrero Power Plant is raising hopes that the end could be in sight for the controversial fossil-fuel-fired facility.

An ordinance proposed by Sup. Sophie Maxwell suggests that the entire facility — including the primary unit 3 and the smaller, diesel-fired units 4, 5, and 6 — could be shut off without having to create any new fossil fuel generation within city limits. The legislation would direct the San Francisco Public Utilities Commission to figure out how to bridge the in-city electric generation gap using energy efficiency, renewable power, and other alternatives.

Meanwhile, a lawsuit filed against Mirant by City Attorney Dennis Herrera targets Mirant’s failure to perform seismic upgrades. The effort wouldn’t close the plant directly, but could make it more burdensome for Mirant to do business here. Mirant did not return calls for comment.

"Mirant has been given a free pass for a while, and the city doesn’t want to give it to them any more," Deputy City Attorney Theresa Mueller told the Guardian. "Part of the reason they’ve gotten away with not doing it is because it was expected to close."

City efforts to replace the Mirant plant’s power with combustion turbines that San Francisco already owns were derailed last year after Mayor Gavin Newsom withdrew his support for the plan, instead backing an alternative pushed by Pacific Gas & Electric Co. that would have retrofitted the Mirant plant, a proposal that consultants said didn’t pencil out and that failed to win Board of Supervisors’ approval (see "Power possibilities," 11/5/08).

Despite various city efforts to shutter the plant going back nearly a decade, Mirant Potrero still runs an average of 20 hours per day, according to figures released by the California Independent System Operator (Cal-ISO). In 2007, the plant released 235 tons of harmful pollutants into the air, and 336,300 tons of carbon dioxide.

For now, Cal-ISO requires Mirant to continue running to guarantee that the lights would stay on in the city even if major transmission lines fail. But with the installation of the Trans Bay Cable — a high-voltage power cord that will send 400 MW of electricity under the bay from Pittsburgh in 2010 — Mirant’s largest unit will be unnecessary.

"We assume that the Trans Bay Cable will be in service sometime in mid 2010. We can then drop Potrero [unit 3]" from the reliability contract, says Cal-ISO spokesman Gregg Fishman. The dirtier, diesel-powered units 4, 5, and 6 would still be required, he says.

Not everyone accepts this as the final word on the matter. Maxwell’s legislation calls for the SFPUC "to take all feasible steps to close the entire Potrero power plant as soon as possible." That ordinance, expected to go before the Land Use Committee on May 11, would direct the SFPUC to update a plan for the city’s energy mix, called the Electricity Resource Plan, to reflect a goal of zero reliance on in-city fossil-fuel generation.

The original plan, issued in 2002, was also designed to eliminate the Potrero plant. This time around, key assumptions have changed. Last year, as Newsom and some members of the Board of Supervisors battled over the Mirant-related projects, PG&E sponsored a study indicating that the city might not need new local power generation.

Maxwell’s new proposal, citing information from the PG&E assessment, now suggests that after the installation of the Trans Bay Cable and other transmission upgrades, the electricity gap for in-city generation will be much smaller than previously assumed. This gap, which Joshua Arce from the Brightline Defense Project likes to refer to as the "magic number," has apparently shrunk to 33 MW in 2012, as opposed to 150 MW. But Arce said, "We want the magic number to be zero."

Barbara Hale, assistant manager for power at the SFPUC, confirmed that the city agency was preparing to update the plan and noted that it would likely contract with a Colorado-based firm, Rocky Mountain Institute, to do it. "We are hoping we can meet San Francisco’s electricity needs in a way that does not involve fossil fuel generation in San Francisco," Hale told the Guardian.

Encouraged by the recent activity, environmental justice groups are organizing for what they hope will be the last push to shut down the Potrero plant. Tony Kelly, president of the Potrero Boosters and an activist on power plant issues, is optimistic. "There really is an end in sight to that power plant," he says.

Some eyebrows have been raised over the implications of the Trans Bay Cable, which by most accounts will be plugged into a fossil fuel-powered facility in Pittsburgh. "We really are going to be highlighting that San Francisco needs to take responsibility … so that we don’t have clean air on the backs of poor people and people of color in the East Bay," says Bradley Angel, executive director of Greenaction for Health and Environmental Justice.

Nor is everyone feeling optimistic that the closure of the plant is near. Joe Boss, a member of the city’s Power Plant Task Force for about nine years, says he still doesn’t expect Cal-ISO to budge, and believes the city will have to live with the Potrero plant for years to come.

Fishman, from Cal-ISO, said that as things stand, units 4,5, and 6 will "almost certainly" still be required. Almost. "Between now and when the Trans Bay Cable is in service, we can conduct … studies on transmission projects that are officially presented to us," he added. "Based on the hard data that comes from those studies, we may reevaluate the need for local generation."