Photo by Rebecca Wilkowski

Photo by Rebecca Wilkowski

Need for Replacement Generation Questioned

May 2008

Forty-Year Old Potrero Power Plant Continues to Pollute Southeast San Francisco

By Deia de Brito

Almost a decade ago the Potrero Power Plant Citizen’s Task Force was created by the San Francisco Board of Supervisors to examine Mirant Corporation’s proposal to construct a 540 megawatt (MW) generating station to replace the existing Potrero Power Plant, San Francisco’s largest single pollution source.  Had the California Energy Commission approved the proposal, the new, larger facility would have operated for at least a third of a century.  Mirant pitched the plant, in part, as a way of replacing the Hunters Point Power Plant, which was ultimately shuttered two years ago in exchange for the development of Pacific Gas and Electric Company’s multi-million dollar Jefferson-Martin transmission line.

For several years the Task Force, among others, fought to stop construction of the larger facility. “Mirant was going to expand the plant to meet San Francisco’s energy needs but they wanted to build this huge plant that was way bigger than it needed to be,” said John Borg, a former Task Force member who’s lived catty-corner from the Potrero Power Plant for almost two decades.   “Once generation is built, the power companies make money by keeping those things running.”  In 2004, the Energy Commission declined to grant Mirant a license for its proposed generating station.  But the battle to reduce polluting air and greenhouse gas emissions in Southeast San Francisco wasn’t over.

The 362 MW Potrero Power Plant has been spewing particulate matter, volatile organic compounds, NOx, and sulfur dioxides in Southeast San Francisco for 43 years, contributing to the highest number of asthma hospitalizations in the City, according to the San Francisco Department of Public Health.  The plant consists of Unit Three – which runs on natural gas and can produce 206 MW – and three diesel peakers, each of which can generate 52 MW.  The diesels are responsible for 60 percent of the plant’s emissions, but run only three percent of the time.  The plant’s once-through cooling system sucks in Bay water and dumps it back out at high temperatures, killing millions of larval fish in the process, and stirring up cancer-causing PCBs and mercury lodged in the sediment.

In 2002, the Board of Supervisors adopted the San Francisco Electricity Resource Plan, which called for closure of both the Hunters Point and Potrero Power Plants if they could be replaced with other energy sources and management programs.  The following year the San Francisco Public Utility Commission (SFPUC) revealed plans to site four natural gas-fired combustion turbines – known as CTs – as a way to replace the power generated by the Hunters Point Power Plant. The City obtained the CTs from the state as part of a settlement with Kentucky-based Williams Companies, Inc., for cheating California ratepayers during the turn-of-the-century energy crisis.

The California Independent System Operator (Cal-ISO) – a quasi-governmental agency responsible for ensuring statewide electricity reliability – demanded that at least three of the CTs be sited within San Francisco.  And the California Department of Water Resources, which would hold the contract for CT-generated power, urged the City to complete the siting process as soon as possible.  In response to these pressures District 10 Supervisor Sophie Maxwell and the SFPUC supported construction of three CTs in Dogpatch, alarming many community members.  Borg, who regularly attended community meetings regarding the CTs, said Southeast San Francisco residents couldn’t believe that the City was going to put more fossil fuel plants in San Francisco’s most environmentally-impacted community, after years of fighting to shut-down the Hunters Point and Potrero plants.  Save Potrero Air Now was organized to advocate for the closure of both existing power plants before any new significant polluting activities could be sited in the area.  In 2004 the Task Force convinced the Board of Supervisors to agree to the CTs only if Cal-ISO committed to closing the Potrero Power Plant by 2009.

However, according to Bay Area Air Quality Management District Engineering Manager, Barry Young, Potrero’s diesel units will have to be closed in 2009 in any event because of a 2006 federal regulation that limits emissions from non-gaseous fired turbines.  And the CTs may not be significantly less polluting than Potrero Unit Three.  “Emission factors are basically the same for the [CTs] and for Unit Three,” said Young.  “I would say the [Unit Three’s] natural gas fired boiler, controlled with SCR [selective catalytic reduction], is a similar public health concern as the new gas turbines.”  Likewise, the San Francisco Regional Water Board is requiring that Mirant demonstrate that the plant’s once-through-cooling system isn’t polluting the Bay, to upgrade, or to close down by December 2008. “They may get a temporary waiver allowing them to continue until [the CTs] are completed,” said SFPUC Project Manager Karen Kubick.

Many Southeast San Francisco residents remain opposed to the CTs, especially with the addition of the Trans Bay Cable to the City’s energy infrastructure.  The 55-mile long transmission line, which will be capable of conveying 400 MW, will run from a substation in the City of Pittsburg – also owned by Mirant Company – to Dogpatch.  The Trans Bay Cable is scheduled to be completed by the end of 2009.  Cable operation could result in substantial increases in polluting air and greenhouse gas emissions in the East Bay, where the region’s largest power plant complex – and, at 54 years, one of the oldest – is capable of generating 2,000 MW. 

Task Force member Steven Moss voted in favor of the CTs as the most expeditious way of closing the Potrero Power Plant.  But that was before the Trans Bay Cable, which Moss opposed, received its final approvals.  “Cal-ISO’s biggest PR threat is that without the CTs or the Potrero Power Plant, San Francisco could face electrical outages,” said Moss, who also serves as the Executive Director of San Francisco Community Power, and is the View’s publisher. “But, with the Trans Bay Cable, combined with ongoing efforts to increase adoption of energy efficiency, demand response, and solar, the available evidence would seem to suggest that the threat of outages is quite low, even without much, if any, in-City generation.”   Last year SF Power admonished SFPUC “that before long Southeast San Francisco may be left with the worst possible outcome: the Trans Bay Cable, the CTs, and the Potrero Power Plant will operate simultaneously.” 

Eric Brooks, a campaign coordinator for the Green Party Sustainability Working Group, agreed with Moss.  According to Brooks, if the CTs are approved ratepayers will pay $223 million that could otherwise have been invested in renewables.  “Cal-ISO refuses to recognize renewable energy and efficiency,” said Brooks. “They say solar is not on all the time, but the really hot days when we would actually need in-City generation are on the days when the sun is out. And efficiency gets rid of demand, reducing the need for a power plant.”

Attorney Joshua Arce of Brightline Defense Project – which filed a lawsuit last year against the U.S. Environmental Protection Agency alleging that CT development would violate greenhouse gas regulations under the Clean Air Act – claims that Cal-ISO spokesman Gregg Fishman stated that with the Trans Bay Cable, the CTs would not be necessary to ensure San Francisco’s electric reliability. In an article in Engineering News Record, Fishman noted that “The Trans Bay Cable project will eliminate at least some of the need for local generation.”

“There was hope on the public’s side that we could come up with an alternative but the path is determined by Cal-ISO,” Kubick said, “We’ve asked Cal-ISO on numerous occasions about minimum capacity - if we really need four turbines – and they said ‘yes’.”  According to the San Francisco Examiner, Cal-ISO spokeswoman Stephanie McCorkle claims that the City never formally proposed any plans other than the CTs to shut down the Potrero Power Plant.  “Cal-ISO will point at SFPUC and say, ‘it’s up to them,’ and SFPUC will blame Cal-ISO. They’ve been doing it for years,” said Eric Brooks.  

A half-decade after the City obtained the CTs the turbines remain stored in an out-of-state warehouse.  An agreement with J-Power USA to develop the project fell through late last year.  Last month SFPUC presented a proposal for the CTs to be sited by Cleveland-based Independent Construction Company. According to Kubick, the new agreement is less expensive and provides more benefits to San Francisco.  The agreement is currently being considered by the Mayor, and will likely be voted on at a May 5 Board of Supervisor’s meeting.

In response Supervisor Michela Alioto-Pier introduced a resolution that calls for an analysis of the need for the CTs – as well as an update of the Electricity Resource Plan – in light of the Trans Bay Cable and implementation of energy management programs; and Supervisors Chris Daly and Ross Mirkarimi introduced an amendment requiring the Potrero Power Plant be shut-down before the CTs become operational.  But Supervisor Sophie Maxwell, who strongly supports the CTs as essential to closing the Potrero Power Plant, may have effectively killed the resolution by referring it to the Land Use and Economic Development Committee, of which Maxwell, Gerardo Sandoval and Aaron Peskin are members.  As of this writing it seems likely that the Board will endorse the CT project.

“A concerted effort from San Francisco’s political elders would pretty much dictate an outcome, no matter what Cal-ISO currently says,” said Moss. “After all, it was the City that originally brokered the deal for the combustion turbines in the first place.”


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