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San Francisco Electric Reliability Project (SFERP) - Docket # (04-Afc-1)

Project Title:

San Francisco Electric Reliability Project (SFERP)


The City of San Francisco


The project would be located adjacent to the San Francisco Bay in the Potrero District of San Francisco, within the existing Potrero Power Plant site, owned and operated by Mirant Potrero, LLC. The SFERP would be located on a portion of the previously proposed Potrero Unit 7 site.

Project Objectives

The SFERP is being pursued by the City to reduce the need for existing unreliable and highly-polluting in-City generation while maintaining reliability of the electric system. According to the California Independent System Operator, the SFERP would enable closure of the Hunters Point Power Plant, a City objective since 1998, provided the eight transmission projects that are currently planned or under development are completed. The SFERP would also support closure of old units at the Potrero Power Plant as further transmission upgrades, renewable resources and improvements in energy efficiency are put into place within, and in the vicinity of, the City.


The SFERP would consist of a nominal 145 megawatt (MW) simple-cycle plant, using three natural gas-fired LM 6000 gas turbines and associated infrastructure.

The project would include the construction of a new air insulated 115-kV switchyard on the west side of the site. A pipeline tie-in would be made to an existing PG&E natural gas load center located adjacent to the PG&E Potrero Substation. Process water for the project would be delivered via a City water pump station located on Marin Street near Cesar Chavez to a new water treatment plant located on the southern portion of the project site, adjacent to 23rd Street.


Construction of the generating facility, from demolition, if applicable, site preparation and grading to commercial operation, is expected to take approximately 12 to14 months. Commercial operation is planned for the 2nd Quarter of 2006.

Commercial Operation:

The Applicant intends to operate the facility up to 12,000 hours per year total for the 3 combustion turbines.


The project would consist of three General Electric LM 6000 Sprint Combustion Turbine Generators (CTGs) equipped with water injection to control oxides of nitrogen (NOx) emissions, and power augmentation. SCR would be used for further NOx control. An oxidation catalyst and associated support equipment would also be provided.


The generating units that comprise the SFERP have been made available to the City as part of a settlement between the Williams Energy Marketing and Trading Company and a large number of parties including numerous state entities and the City. The settlement resolved claims associated with the 1999-2001 energy crises and provided the City with four natural-gas-fired- LM 6000 turbines along with a budget for their development. The City has a power purchase agreement for sale of the output of the four turbines to the California Department of Water Resources at cost, provided that certain conditions are met.

The CityÕs four unit project to improve electric reliability and provide for closure of existing in-City generation will consist of two separate sites. The SFERP at the Potrero site, for which this AFC is being submitted, consists of three of the units available to the City for development. The City is exploring alternative locations to site the fourth unit. Once a site for the fourth unit is identified, the City will assess and comply with permitting requirements that apply to that unit in light of the facilityÕs size, configuration, and location.

Transmission Line:

Electrical generation would be at 13.8 kilovolts, which would be stepped up with 115-kilovolt (kV) step-up transformers. The transmission line would interconnect the facility with PG&EÕs existing 115 kV electrical substation located adjacent to plant site on its west boundary. A new overhead transmission line would tie the adjacent PG&E substation to the plant switchyard.


Natural gas for the facility would be delivered through a new 250-foot-long, 12-inch diameter pipeline that would connect to PG&EÕs San Francisco Load Center, which is located on the western portion of the PG&E Potrero Substation. This service would be connected to a booster compressor station that would be part of the SFERP facility.

Water Supply:

The City would provide process water to the SFERP through a new water pumping station (WPS) for onsite water treatment at the facility. The WPS would be located in an existing combined sewer system structure and would include three variable frequency drive pumps (two operational and one standby). A one-mile pipeline would connect the WPS and the SFERPÕs onsite treatment system. The one-mile pipeline consists of two parts. The southern portion of the alignment extends north from Marin Street along Mississippi Street for about 480 feet, and then east on Cesar Chavez Street for about 1,400 feet. This portion of the line would generally use an existing collection box that terminates near the intersection of Cesar Chavez Street and Indiana Street. The northern portion of the pipeline would run about 560 feet east on Cesar Chavez Street, then 1,880 feet north on Tennessee Street and then 1,360 feet east on 23rd Street to the SFERP water treatment facility inlet structure, located on the southern boundary of the project site. The onsite treatment system would be designed to produce Title 22-quality recycled water.

Air Quality


Emission Controls:

The site is located in an area designated as nonattainment for State and federal ozone air quality standards, and for State fine particulate matter (PM10) standards. An assessment of the impact to air quality was performed using detailed air dispersion modeling. The air impacts from the Project will be mitigated by the use of state-of-the-art combustion turbine emission control technology. The City has issued a request for proposals to emission reduction credit (ERC) holders to obtain sufficient ERCs to meet the offset requirements for this project. The City has committed to make reasonable efforts to obtain offsets locally. ERCs would be obtained to offset increases in emissions of precursor organic compounds (PVOCs) and NOx (both precursors of ozone). In addition, the City intends to develop a PM10 mitigation and a community benefits plan.


Plant wastewater and reject water from the SFERPÕs water treatment system would be discharged into the CityÕs combined sewer system, which routes the waste to the Southeast Water Pollution Control Plant (SEWPCP).


The initial capital cost of the SFERP is estimated to be $140 million. The estimated value of materials and supplies that would be purchased locally (within San Francisco) during demolition/construction is between $2 and $3 million.

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