APPENDIX A DETAILED PROJECT DESCRIPTION

A.9   CAISO-RELATED PROJECTS

A.9.1   Background

The CAISO management determined that the Trans Bay Cable Project is needed to ensure reliable operation of the electrical transmission system within the San Francisco Peninsula area (CAISO, 2005d). Further, the CAISO management requested that the CAISO Board of Governors approve the Project as a necessary addition to the CAISO Controlled Grid. As such, the Project was assessed as a needed component of the CAISO's long-term transmission solution that includes several related projects to ensure a reliable load serving capability for the area, and to mitigate violation of reliability planning standards beginning in 2012. These related projects are identified in the Revised Action Plan for San Francisco and in the San Francisco Peninsula, Long-Term Transmission Planning Study, Phase 2, Study Plan (CAISO, 2004) which are summarized below.

A.9.2   Revised Action Plan for San Francisco

In 2004, the CAISO worked closely with the City and County of San Francisco (CCSF), PG&E, and interested stakeholders to establish a plan that describes the transmission and generation requirements necessary to reliably serve the San Francisco Peninsula area electrical load while allowing for the release of all existing generation at Hunters Point and Potrero Power plants from their Reliability Must-Run (RMR) Agreements. This Action Plan, was adopted by the CAISO Board of Governors in November 2004 and is currently being implemented by PG&E, the CCSF, and the CAISO (CAISO, 2004).

The Action Plan was designed to facilitate the retirement of old generation in San Francisco; it also contributes to increased flows on the transmission facilities that serve the load in the area. The increased reliance on this transmission infrastructure was addressed in the Action Plan through various transmission additions, upgrades, and re-rates. These related projects which are included in the Action Plan are summarized in Table A.9-1. However, the Action Plan did not assess the impact on the area's future load serving capability beyond 2007 which necessitated the initiation of the Long-Term Transmission Planning Study (see Section A.9.3) to evaluate the suitability of other identified related projects.

A.9.3   Long-term Transmission Planning Study

Recognizing the need to establish a longer-term (10-year) transmission plan once the Action Plan was implemented, the CAISO led the San Francisco Stakeholders Study Group (SFSSG) Phase II, initiating the Long-Term Transmission Planning Study in February 2004 to determine the transmission facilities necessary to reliably serve the electrical load in this area through at least 2018. The results of this study indicated that once the Action Plan was fully implemented, it would provide sufficient load serving capability for the San Francisco Peninsula area through 2011, including support for an additional 378 MW of San Francisco


TABLE A.9-1
CAISO-RELATED PROJECTS1


Project Purpose Estimated Completion Date/Status Issue2 Resolution of Issue
Potrero Static VAR Compensator Release Hunters Point Units 2 & 3 from their RMR Agreements Completed NERC/WECC/CAISO Planning Standards This project allowed PG&E to meet planning requirements with Hunters Point Power Plant Units 2 and 3 released from their RMR Agreements.
San Mateo-Martin No. 4 Line Voltage Conversion Release Hunters Point Units 1 & 4 from their RMR Agreements Completed NERC/WECC/CAISO Planning Standards This project in combination with the other listed projects allows PG&E to meet planning requirements with Hunters Point Power Plant Units 1 and 4 released from their RMR Agreements.
Ravenswood 2nd 230/115 kV Transformer Project Release Hunters Point Units 1 & 4 from their RMR Agreements Completed NERC/WECC/CAISO Planning Standards This project in combination with the other listed projects allows PG&E to meet planning requirements with Hunters Point Power Plant Units 1 and 4 released from their RMR Agreements.
San Francisco Internal Cable Higher Emergency Ratings Release Hunters Point Units 1 & 4 from their RMR Agreements Completed: To Be Used Upon Completion of the Jefferson-Martin 230 kV Project NERC/WECC/CAISO Planning Standards These ratings are an interim solution that in combination with the other listed projects allows PG&E to meet planning requirements with Hunters Point Power Plant Units 1 and 4 released from their RMR Agreements. In 2007, a third Martin-Hunters Point 115 kV cable will replace the emergency ratings.
Tesla-Newark No. 2 230 kV Line Reconductoring Release Hunters Point Units 1 & 4 from their RMR Agreements Completed RMR Criteria This project in combination with the other listed projects allows PG&E to meet planning requirements with Hunters Point Power Plant Units 1 and 4 released from their RMR Agreements.
Ravenswood-Ames 115 kV Lines Reinforcement Release Hunters Point Units 1 & 4 from their RMR Agreements Completed RMR Criteria This project in combination with the other listed projects allows PG&E to meet planning requirements with Hunters Point Power Plant Units 1 and 4 released from their RMR Agreements.
San Mateo 230 kV Bus Insulator Replacement Release Hunters Point Units 1 & 4 from their RMR Agreements Completed Operations Requirement During San Mateo Bus Wash Eliminate bus wash at San Mateo 230 kV bus will reduce the 400 MW generation operational requirement to less than 200 MW.
Potrero-Hunters Point (AP-1) 115 kV Cable Release Hunters Point Units 1 & 4 from their RMR Agreements December 2005, CPUC Permit Approval Granted NERC/WECC/CAISO Planning Standards This project in combination with the other listed projects allows PG&E to meet planning requirements with Hunters Point Power Plant Units 1 and 4 released from their RMR Agreements.
Jefferson-Martin 230 kV Line Release Hunters Point Units 1 & 4 from their RMR Agreements December 2005 to March 2006, Under Construction NERC/WECC/CAISO Planning Standards This project in combination with the other listed projects allows PG&E to meet planning requirements with Hunters Point Power Plant Units 1 and 4 released from their RMR Agreements.
Potrero 3 SCR Retrofit Release Hunters Point Units 1 & 4 from their RMR Agreements Completed NERC/WECC/CAISO Planning Standards This project ensures the availability of Potrero 3 at full capacity thereby reducing overall Greater Bay Area RMR requirements. This project or the reduced capacity available without the retrofit in combination with the other listed projects allows PG&E to meet planning requirements with Hunters Point Power Plant Units 1 and 4 released from their RMR Agreements.
San Francisco Electric Reliability Project and San Francisco Airport Electric Reliability Plant Release Potrero Unit 3 from its RMR Agreements December 2006 or Later NERC/WECC/CAISO Planning Standards These projects will allow PG&E to meet planning requirements with Potrero 3 released from its RMR Agreements. CEC permit suspended due to a change in where to site near Potrero.
Upgrade the Newark- Dumbarton 115 kV Line Release Potrero Units 4, 5, & 6 from their RMR Agreements (assumes previous completion of Peaking Power Plants by the City of San Francisco) May 2006,
Engineering in
Progress
NERC/WECC/CAISO Planning Standards This upgrade is needed in combination with the other listed mitigations to allow PG&E to meet planning requirements with Potrero Units 4, 5, and 6 released from their RMR Agreements.
Upgrade the Bair-Belmont 115 kV Line Release Potrero Units 4, 5, & 6 from their RMR Agreements (assumes previous completion of Peaking Power Plants by the City of San Francisco) Scheduled for May 2007 NERC/WECC/CAISO Planning Standards This upgrade is needed in combination with the other listed mitigations to allow PG&E to meet planning requirements with Potrero Units 4, 5, and 6 released from their RMR Agreements.
Upgrade the Metcalf-Hicks & Metcalf-Vasona 230 kV Lines Release Potrero Units 4, 5, & 6 from their RMR Agreements (assumes previous completion of Peaking Power Plants by the City of San Francisco Scheduled for May 2007 NERC/WECC/CAISO Planning Standards This upgrade is needed in combination with the other listed mitigations to allow PG&E to meet planning requirements with Potrero Units 4, 5, and 6 released from their RMR Agreements.
Add Voltage Support at Ravenswood Substation Release Potrero Units 4, 5, & 6 from their RMR Agreements (assumes previous completion of Peaking Power Plants by the City of San Francisco) Scheduled for May 2007 NERC/WECC/CAISO Planning Standards This upgrade is needed in combination with the other listed mitigations to allow PG&E to meet planning requirements with Potrero Units 4, 5, and 6 released from their RMR Agreements.

1   Source: CAISO, 2004.
2   Abbreviations: NERC – National Energy Reliability Council; WECC – Western Electrical Coordinating Council.


Peninsula area load and a projected load growth of approximately 15 to 20 MW per year. However, this technical assessment concluded that there would be reliability planning standard violations that would occur in the greater San Francisco and northern San Mateo County area beginning in 2012.

Given the geographical location of the load in the San Francisco Peninsula area and the difficulty in locating new generation resources there, new transmission infrastructure and/or transmission upgrades are required to be constructed either from the south or from the east across San Francisco Bay. The technical aspects of five transmission alternatives were evaluated in the study to determine their viability for addressing the identified reliability planning standard violations. To be consistent with the CAISO Tariff, the Trans Bay Cable Project was included as one of the alternatives to be considered in the overall study effort. Accordingly, the five alternatives evaluated in the CAISO study included:

  1. Status Quo – This alternative proposes to do nothing beyond utilizing the transmission facilities and generation planned to exist once the Action Plan for San Francisco is fully implemented by the end of 2007.

  2. Upgrade and Replace Existing Facilities – This alternative proposes to utilize existing transmission infrastructure to support existing and anticipated load growth in the area. When needed, employ replacing, reconductoring, re-rating and operating alternatives to mitigate transmission system overloads and low voltages.

  3. Trans Bay Cable Project – This alternative proposes to build a new 400 MW HVDC submarine DC cable proposed by an independent developer, Babcock & Brown, between PG&E's Pittsburg substation in the East Bay area and PG&E's Potrero substation in San Francisco for operation by 2009.

  4. Moraga-Potrero 230 kV Line – This alternative proposes to build a new 230 kV AC line from the Moraga substation in the East Bay area to the Potrero substation in San Francisco. This new line would include a combination of overhead or underground facilities from Moraga to the San Francisco Bay and then run beneath San Francisco Bay to the Potrero substation.

  5. Tesla-Potrero 230 kV Line – This alternative proposed to build a new 230 kV circuit from the Tesla substation to San Ramon substation, reconnection at the San Ramon substation, reconductoring of 230 kV circuits between San Ramon and East Shore substations, and installing a new 230 kV circuit from the East Shore to Potrero substations. The portion of the project between the East Shore and Potrero substations would include a new line across and above the San Francisco Bay and a new underground cable approximately parallel to the existing San Mateo - Martin 230 kV cable, which would extend to the Potrero substation.

The study concluded that all of the evaluated transmission alternatives, except for the "Status Quo" alternative, could address the identified reliability planning standard violations, provided they could be completed by the time they were needed. The study also concluded that constructing a new transmission line to San Francisco from across the San Francisco Bay would be preferred over alternatives that approached the San Francisco Peninsula area from the south through the peninsular corridor. The Trans Bay Cable Project and the Moraga – Potrero 230 kV line were the only alternatives that approach San Francisco from across the Bay. As such, these are the only "across the Bay" alternatives that were considered in the CAISO's final analysis of the preferred long-term transmission solutions for the area.

The CAISO study determined that given the technical analysis results presented, there was no compelling evidence to conclude that constructing a new transmission line from Moraga (Moraga-Potrero alternative) would be technically superior over a new transmission line built from Pittsburg (Trans Bay Cable Project). The Trans Bay Cable Project was the only alternative being proposed as a viable project at that time. The study concluded that siting an alternative such as the Moraga – Potrero alternative through the City of Oakland, while not impossible, would likely be difficult to complete in a timely manner.

The study concluded that installation of the Trans Bay Cable Project in 2009 would significantly improve reliability of the San Francisco Peninsula area electrical system. Existing generation within San Francisco is expected to reduce significantly after implementation of the Action Plan in late 2007, which will increase San Francisco Peninsula's operational constraints and locational capacity requirements. The proposed Project, with a 2009 in-service date, would significantly reduce expected locational capacity requirements and the need for special protection schemes that are currently in place to shed firm load for critical double contingency disturbances for the San Francisco Peninsula Area.


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