New CEC Staff Report on Mitigation Options for Contingencies Threatening Southern California Electric Reliability


A new CEC staff report has been made available in preparation for the August 29th workshop on Electric Reliability in Southern California. Click here to review the Report, Mitigation Options for Contingencies Threatening Southern California Electric Reliability. The Executive Summary is excerpted below.

Executive Summary

Immediately following Southern California Edison’s June 27, 2013, announcement closing the San Onofre Nuclear Generating Station, Governor Edmund Brown Jr. requested that energy agencies, utilities, and air districts develop a plan for replacement of the power plant and the assurance of electric service reliability in Southern California. The Energy Commission, California Public Utilities Commission, California Independent System Operator, and California Air Resources Board developed a preliminary plan and presented it at a September 9, 2013, workshop as part of the 2013 Integrated Energy Policy Report proceeding.

The preliminary plan was a multipronged effort to satisfy California Independent System Operator estimates of resource requirements to assure reliability, as measured by local capacity area requirements. Local capacity areas represent portions of the electricity grid for which load cannot be fully satisfied by imports; therefore some resources must be located within the boundaries of such areas. For example, the California Independent System Operator has determined that the Los Angeles Basin is such a local capacity area, and within it in year 2025 about 8,300 MW of resources must be located and available to the Independent System Operator. Preferred resources (such as energy efficiency savings, renewable generation, and demand response programs) and conventional natural gas-fired generation were expected to be part of the resource mix. The preliminary plan was not finalized or adopted by any agency, but both the California Public Utilities Commission and the California Independent System Operator subsequently examined the issue in their respective proceedings and have made decisions compatible with the plan.

The California Public Utilities Commission has authorized procurement for Southern California Edison Company and San Diego Gas & Electric Company and has approved power purchase agreements for most of these resource additions. The Energy Commission is processing permits for a variety of proposed generation projects, some of which correspond directly to California Public Utilities Commission-approved power purchase agreements. The California Independent System Operator has authorized transmission system upgrades that address the voltage instability concerns created by the retirement of San Onofre Nuclear Generating Station.

However, reliability in Southern California rests upon close coordination between retirement of large amounts of fossil-fueled, once-through cooling power plants and the development of appropriate resources in locations needed to assure that local capacity requirements are satisfied. If this resource development continues as planned, reliability in Southern California would likely be assured. Accordingly, the energy agencies and the California Air Resources Board have been working collaboratively to track all types of preferred resource, conventional power plant, and transmission upgrade deployment and develop a contingency plan.

Contingency mitigation measures to ensure electric service reliability need to be developed that can be triggered if resource development expectations do not match requirements. A short-term measure is a possible request to the State Water Resources Control Board to defer compliance dates for specific once-through cooling facilities for which a specific new power plant, once it becomes operational, would allow retirement of the older facility. (Once-through cooling involves water that is withdrawn from a source, circulated through the heat exchangers of the power plant, and then returned to a water body at a higher temperature.) A longer-term option would be conventional power plant development relying upon facilities that have already obtained siting permits, but still require approval of a power purchase agreement to satisfy financial requirements and allow construction.

This staff report represents a work in progress to establish contingency mitigation options. It builds upon work described in the 2015 Integrated Energy Policy Report. Two mitigation options have been developed:

  • Once-Through Cooling Compliance Date Deferral Option: Use the process established by the State Water Resources Control Board to defer the compliance date for an existing generating facility until replacement resources are built and synchronized to the grid.
  • New Generation Construction Option: Rely upon already-permitted projects. Energy Commission staff prepared this report with input from the technical staff of the other agencies included in the Southern California Reliability Project.
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