Generation Interconnection Tariff History
The California Independent System Operator (CAISO) interconnection procedures in effect prior to July 1, 2005 were the “Amendment 39” procedures.
The Amendment 39 procedures were applicable to Small Generating Facilities interconnecting to the CAISO Controlled Grid in accordance with Section 1.3 of the SGIP in CASIO tariff Appendix S and to Large Generating Facilities in accordance with Section 5.1 of the LGIP in CAISO tariff Appendix U.
Amendment 39 Procedures
Appendix W of the CAISO Tariff * Effective prior to July 1, 2005
Effective July 1, 2005 the Federal Energy Regulatory Commission (FERC) Order established Interim LGIP procedures and ordered the California Independent System Operator (CAISO) to create a Centralized Interconnection Study process where the CAISO itself conducts the Generation Interconnection Studies.
Generators above 20 MW were considered to be Large Generators and followed the Large Generation Interconnection Procedures (LGIP) for Transmission System Interconnections.
Generators 20 MW and below were considered Small Generators and followed the Small Generator Interconnection Procedures (SGIP) for Transmission System Interconnections
As of November 1, 2005 the CAISO, SCE, SDG&E, PG&E made compliance filings to establish the Centralized Interconnection Study process. In May, 2006 FERC approved this CAISO study process.
Large Generator Interconnection Procedures (LGIP) – Appendix U of the CAISO Tariff * Effective July 1, 2005
This LGIP process, identified as Appendix U in the CAISO tariff, was applicable for projects that submitted an Interconnection Request (IR) with the CAISO on or before June 2, 2006. These projects continued to be studied serially as listed in the CAISO’s Controlled Grid Generation Queue.
On May 15, 2008 the CAISO filed to implement the Generator Interconnection Process Reform (GIPR) with FERC including a Petition for Waiver of the existing Tariff Provisions. FERC granted the waiver on July 14, 2008 and the CAISO filed Draft GIPR LGIP tariffs on July 28, 2008. On September 26, 2008 FERC approved the CAISO's GIPR LGIP Tariff.
This GIPR LGIP process, identified as Appendix Y in the CAISO tariff, was applicable for projects that submitted an IR with the CAISO after June 2, 2008. These projects were to be studied in clusters.
On October 19, 2010 the CAISO filed provisions to the generator interconnection process tariff known as the Generator Interconnection Procedures (GIP). GIP is an integrated cluster study process, which assigns both small and large generator interconnection requests to annual queue clusters for study in groups of electrically related projects.
On December 16, 2010, the Federal Energy Regulatory Commission conditionally approved the GIP tariff provisions. These new procedures combined the small (SGIP) and large (LGIP) interconnection process into a single cluster approach and streamlined the timelines under the study process.
On October 1, 2011 the CAISO filed provisions to the generator interconnection process tariff known as Generator Interconnection Procedures Phase 2 (GIP-2).
GIP Phase 2 addresses carryover issues from the GIP and other issues that encompass generator technical specifications, information accessibility, non-conforming large generator interconnection agreement provisions, study assessment methodology and posting requirements. FERC approved the GIP-2, effective as of December 1, 2011, as requested by the ISO.
The ISO’s FERC filing of the GIP-2 amendment to the ISO tariff, which the Commission conditionally accepted on January 30, 2012
The GIP process for Interconnection Requests is identified as Appendix Y of the CAISO tariff. The GIP includes, in addition to the existing generator cluster study process, two alternative study processes: an “Independent Study Process”, and a “Fast Track Process”.
Generator Interconnection and Transmission Allocation Procedures (“GIDAP”)
On July 24, 2012, FERC conditionally accepted the CAISO’s GIDAP Tariff filing, to integrate its Transmission Planning Process (TPP) and Generation Interconnection Procedures (GIP). GIDAP establishes a new generation interconnection tariff for projects in Cluster 5 and going forward. The GIDAP has a single cluster application window starting with queue Cluster 6, which will open on April 1 and close April 30th of each year. The GIDAP process for Interconnection Requests is identified as Appendix DD of the CAISO tariff. The GIDAP contains the Generator Interconnection and Deliverability Allocation Procedure. In this new process, renewable generation requests that are in excess of the CPUC’s 33% portfolio will have the option of being fully deliverable if they choose to fully fund the Network Upgrades that provide Full Capacity Deliverability Status for them. The MWs in excess of 33% will not receive Full Capacity Deliverability Status through the ratepayer funded Network Upgrades.
Transmission Owner (TO) Tariff
Details governing the interconnection application process are contained in the Transmission Owner (TO) Tariff of the Participating Transmission Owner (PTO) (i.e. SDG&E). In order to promote consistency throughout the California Independent System Operator (CAISO) Controlled Grid, the CAISO Tariff and the PTO's TO Tariff have been modified.
Interconnection Customers (IC)
Interested IC’s or other customers requesting interconnection to SDG&E's electric transmission system should contact the California ISO.
For questions regarding generation interconnection, please contact the CAISO Project Manager at