Stakeholder center

Participating transmission owner per unit costs - 2025

Started: Feb 25, 2025

Leads
Michael U

The ISO Generator Interconnection Procedures (ISO Tariff DD Appendix 5) requires participating transmission owners to annually update and publish per unit costs for use during the current interconnection study cycle for estimating the cost of facilities required to interconnect generation. Per unit costs are used to develop the cost for reliability and delivery network upgrades and participating transmission owner’s interconnection facilities. The ISO annually publishes draft per unit costs to its website, holds a stakeholder meeting and allows stakeholders to comment on the draft costs. The ISO publishes the final costs in the March to April time frame. The schedule for this annual process is located in Appendix 5 of the interconnection procedures.

Relevant notices Contact us

Status

Development Decision Implementation Completed/Closed
Jul 10, 2025 Final cost guides posted
 Completed

Activities


 https://stakeholdercenter.caiso.com/InitiativeDocuments/LSPGC-2025-Per-Unit-Cost-Guide-Final.xlsx

LSPGC 2025 Per Unit Cost Guide - Final 07/10/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/HWT-2025-Per-Unit-Cost-Guide-Final.xlsx

HWT 2025 Per Unit Cost Guide - Final 07/10/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/GLW-2025-Per-Unit-Cost-Guide-Final.xlsx

GLW 2025 Per Unit Cost Guide - Final 07/10/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/DSLK-2025-Per-Unit-Cost-Guide-Final.xlsx

DSLK 2025 Per Unit Cost Guide - Final 07/10/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/DCRT-2025-Per-Unit-Cost-Guide-Final.xlsx

DCRT 2025 Per Unit Cost Guide - Final 07/10/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/VEA-2025-Per-Unit-Cost-Guide-Final.xlsx

VEA 2025 Per Unit Cost Guide - Final 07/10/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/SDGE-2025-Per-Unit-Cost-Guide-Final.xlsx

SDGE 2025 Per Unit Cost Guide - Final 07/10/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/SCE-2025-Per-Unit-Cost-Guide-Final.xlsx

SCE 2025 Per Unit Cost Guide - Final 07/10/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/PGE-2025-Per-Unit-Cost-Guide-Final.xlsx

PG&E 2025 Per Unit Cost Guide - Final 07/10/2025

Web meeting


 https://youtu.be/C-EvxX01xMM

Video - 2025 Participating Transmission Owner Per Unit Cost Guides - May 08, 2025 05/15/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation-2025Participating-Transmission-Owner-Per-Unit-Cost-Guides-May08-2025.pdf

Presentation - 2025 Participating Transmission Owner Per Unit Cost Guides - May 08, 2025 05/07/2025

View comments


https://stakeholdercenter.caiso.com/InitiativeDocuments/DCRT-Draft-2025-Per-Unit-Cost-Guide.xlsx

DCRT Draft 2025 Per Unit Cost Guide 04/02/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/DSLK-Draft-2025-Per-Unit-Cost-Guide.xlsx

DSLK Draft 2025 Per Unit Cost Guide 04/02/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/GLW-Draft-2025-Per-Unit-Cost-Guide.xlsx

GLW Draft 2025 Per Unit Cost Guide 04/02/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/HWT-Draft-2025-Per-Unit-Cost-Guide.xlsx

HWT Draft 2025 Per Unit Cost Guide 04/02/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/LSPGC-Draft-2025-Per-Unit-Cost-Guide.xlsx

LSPGC Draft 2025 Per Unit Cost Guide 04/02/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/PGE-Draft-2025-Per-Unit-Cost-Guide.xlsx

PGE Draft 2025 Per Unit Cost Guide 04/02/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/SCE-Draft-2025-Per-Unit-Cost-Guide.xlsx

SCE Draft 2025 Per Unit Cost Guide 04/02/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/SDGE-Draft-2025-Per-Unit-Cost-Guide.xlsx

SDGE Draft 2025 Per Unit Cost Guide 04/02/2025

https://stakeholdercenter.caiso.com/InitiativeDocuments/VEA-Draft-2025-Per-Unit-Cost-Guide.xlsx

VEA Draft 2025 Per Unit Cost Guide 04/02/2025