On May 18, 2010, the CAISO Board of Governors approved a revised transmission planning process in an attempt to provide transmission necessary to accommodate additional renewable generation.  The CAISO Board also approved new reliability rules for renewable energy resources. 

The CAISO Board of Governors adopted the new transmission plan to address the transmission needs of generating 33 percent of energy from renewable sources by 2020.  The new transmission planning process adopts a statewide approach, and will consolidate all ISO planning activities in order to move away from the single-project approach.  However, the CAISO Board exempted from the new requirements those state renewable projects that are scheduled to complete construction deadlines under the American Recovery and Reinvestment Act. 

The new transmission planning process is divided into three phases.  In Phase 1, CAISO and other participants in the California Planning Group will develop a conceptual statewide transmission study plan for access to renewable resources.  In Phase 2, the CAISO planners will perform the economic planning studies required under the study plan and finalize the comprehensive statewide transmission plan.   CAISO will designate each of the specific projects of the transmission plan as either a Category 1 or Category 2 element.  Category 1 transmission elements are those the CAISO has a high level of confidence are needed to connect renewable energy to the grid, based on sufficient commercial interest from new generation, or are economically justified.  Category 2 projects are those that are potentially needed, but cannot be approved without further evidence of commercial interest.  During Phase 3, the ISO will receive proposals to build Category 1 projects.

The CAISO Board’s new reliability requirements have been controversial because they would apply the FERC Order No. 661-A Standard for Voltage and WECC Criteria for Frequency to intermittent resources.  CAISO said it is necessary that renewable generation meet the same voltage and reactive power requirements as conventional fossil-fuel generation to maintain reactive power, which is vital for an alternating current transmission structure.  Also, CAISO now will require all new resources to be equipped with fault ride-through capabilities to minimize tripping and down time when a fault occurs.  Finally, CAISO approved a series of generation power management requirements in order to interconnect to the grid.

CAISO expects to file the tariff changes by June 1, 2010 with FERC for approval of the new transmission planning process and other requirements.

The CAISO memos on the revised transmission plan and new requirements are available at http://www.caiso.com/2793/2793ad662d310.pdf and http://www.caiso.com/2793/2793abee1a0a8.pdf.