Assumptions for the 2025-2026 TPP

The Integrated Resource Planning (IRP) process develops a resource portfolio(s) annually as a key input to the California Independent System Operator's (CAISO) Transmission Planning Process (TPP) base case studies, which includes a reliability base case portfolio and a policy-driven base case portfolio.  The California Public Utilities Commission (CPUC) may also transmit additional resource portfolios as inputs for sensitivity studies that test the implications of various policy futures.  This page contains documentation relevant to the development and mapping of resource portfolios for the 2025-2026 TPP.

Transmission Planning Process Ruling and Ruling Development Materials

• 2025-2026 TPP Mapping Ruling, 10/30/2024
• 2025-2026 Transmission Planning Process ruling, 9/12/2024 
• 2025-2026 Transmission Planning Process RESOLVE Analysis, 9/12/2024
• 2025-2026 Transmission Planning Process RESOLVE Package analysis, 9/12/2024 Note: This file is over 5.9 GB.  Please download and open locally
  • 2025-2026 TPP Ruling Cluster Interconnection Limits, 10/10/2024

Methodology for Resource-to-Busbar Mapping

The busbar mapping methodology states guiding principles, establishes mapping criteria, and outlines the iterative inter-agency mapping process. 

• Methodology for Resource-to-Busbar Mapping for the Annual TPP, Ruling version, 9/12/2024 
• Red-lined Methodology for Resource-to-Busbar Mapping for the Annual TPP (red-lined from the 10/05/2023 2024-2025 TPP version), 9/12/2024

Initial Mapping Results for the Proposed Base Case

The Initial Busbar Mapping Dashboard for the Base Case summarizes the initial mapping results, the mapped resources alignment with the busbar criteria, and the analysis used to assess that alignment.

1. Full Dashboard – Initial Mapping for the 25-26 TPP Base Case (11/1/2024)
• This workbook is ~33 MB and includes a summary of the initial mapping results as well as the full analysis, including the calculations, equations, and data used to conduct the mapping and assess the criteria alignment.
2. Compact Dashboard – Initial Mapping for the 25-26 TPP Base Case (11/1/2024)
• This version of the dashboard is ~5 MB and is the smaller, compact version of the mapping results. It includes only the results (fixed numbers) and not the equations, calculations, and supporting reference data that is used to conduct the busbar mapping analysis.

Supplemental data workbooks for initial mapping effort.

1. Baseline Reconciliation and In-development resources (11/1/2024)
2. Land-use and Environmental Screens data (11/1/2024)
3. Commercial Interest analysis from CAISO’s interconnection queue (11/1/2024)
4. Commercial Interest analysis from Cluster 15 applications (11/1/2024)

Webinar – 11/05/2024 – IRP Webinar on the Proposed 2025-26 Transmission Planning Process Portfolios and Draft Busbar Mapping Results

1. Objectives
   1. Familiarize stakeholders with proposed portfolios and busbar mapping process.
   2. Overview the draft mapping results for the proposed base case portfolio.
   3. Provide an opportunity for stakeholders to ask clarifying question about busbar mapping process and draft mapping results.
2. CPUC slides
3. CEC slides
4. Webinar Q&A
5. Webinar Recording | Transcript