Settlements
Settlements are the calculation, billing, and invoicing of charges and payments for market and transmission-related activities between market participants and the ISO. The settlement cycle follows a specific timeline and process for publication of statements, invoices, payment advices, dispute submittals, and payments. Various charging rates, processes, schedules, and documents are listed below.
Payments and charges
Many specific charge type categories are used within settlements and invoice processes according to involvement in the Markets and RC West.
Payments calendar
- California ISO Payments Calendar 202503/31/2025, 2:15 PM
- California ISO Payments Calendar 202503/31/2025, 2:15 PM
- ISO RMR Payments Calendar Tool03/20/2025, 11:04 AM
- California ISO Draft Payments Calendar 202509/20/2024, 10:11 AM
- California ISO Draft Payments Calendar 202509/20/2024, 10:11 AM
- California ISO Payments Calendar 202410/26/2023, 8:12 AM
- California ISO Payments Calendar 202410/26/2023, 8:12 AM
- RC West Annual Payments Calendar10/29/2019, 8:50 AM
ISO charge codes
The ISO uses specific charge codes dependent on the type of charge.
- ISO Charge Code Matrix02/14/2025, 10:36 AM
Market and administrative charge rates
Grid Management Charge (GMC) rates
GMC is assessed to wholesale market customers to recover California ISO costs. This section contains current and historical GMC codes and rates and a sub section detailing the GMC unbundling process from 1998-2000.
GMC rates are based on the budget and grid management charge process.
Emissions and start-up costs
- Start-Up Cost Charge Analysis03/04/2008, 7:49 AM
- Emissions Cost Invoice Template07/09/2010, 4:51 PM
Transmission access charge (TAC) rates
The current transmission access charge is a two-part rate for each megawatt hour of internal load and exports and is used to recover transmission revenue requirements.
High voltage access charge rates
Wheeling access rates
Submittal requirements for participating transmission owner rate changes
- Presentation - Transmission Access Change Process Improvements - Oct 26, 202010/27/2020, 11:23 AM
- Video - Transmission Access Charge Process Improvements05/18/2024, 7:43 PM
Settlement mitigation
Supporting information regarding settlement estimation methodology in the event of a system error.
- Estimation of Invoice Interest Deviation for Trade Date 06-30-201907/03/2019, 10:35 AM
- Estimation of RAAIM Settlement Beginning Trade Date May 1, 201706/18/2019, 8:06 AM
- Estimation of Fifteen-Minute Market Instructed Imbalance Energy EIM for Trade Date Mar 28, 201904/02/2019, 12:51 PM
- Estimation of MLC for Trade Date Mar 2, 201903/06/2019, 8:37 AM
- Estimation of RAAIM Settlement April 2017 Monthly Statement07/17/2017, 3:35 PM
- Estimation of EIM Transfer Quantities v4.006/26/2017, 8:00 AM
- Estimation of Upward Ancillary Service Settlement05/10/2017, 8:33 AM
- Estimation of Convergence Bidding CRR Adjustment Settlement04/27/2017, 10:34 AM
- Estimation of Nodal and Resource Prices (Updated)03/14/2017, 4:27 PM
- Estimation of Weekly Invoice Published Oct 26, 201610/26/2016, 10:48 AM
- Estimation of Weekly Invoice Published Oct 19, 201610/19/2016, 4:07 PM
- Estimation of Marginal Congestion Cost Breakdown Prices10/05/2016, 3:43 PM
- Estimation of Weekly Invoice Published Jun 8, 201606/07/2016, 11:34 AM
- Estimation of May 2015 T+9M Billing03/17/2016, 9:02 AM
- Estimation of Weekly Invoice Published Aug 5, 201508/05/2015, 6:10 PM
- Estimation of April 2015 T+55B Billing07/27/2015, 3:54 PM
Amendment 60 - must offer waiver denial reports
- Total Start-Up Cost: July 17, 2004 - March 31, 200905/14/2012, 12:15 PM
- Total Minimum Load MWs of the Must-Offer Capacity05/14/2012, 11:59 AM
- Total Minimum Load Cost July 17, 2004 - March 31, 200905/14/2012, 11:56 AM
Other processes
- Resources Electing PIRP Protective Measures12/19/2014, 11:31 AM
Invoicing
Invoicing schedules for monthly and annual CRR auctions
- Invoicing Schedule for Jan-Dec 2025 Monthly and 2026 Annual CRR Auctions (Revised)04/21/2025, 9:01 AM
- Invoicing Schedule for Jan-Dec 2023 Monthly and 2024 Annual CRR Auctions (Revised)11/06/2023, 8:17 AM
- Invoicing Schedule for Jan-Dec 2024 Monthly and 2025 Annual CRR Auctions10/26/2023, 8:12 AM
- Invoicing Schedule for Jan-Dec 2022 Monthly and 2023 Annual CRR Auctions (Revised)11/18/2022, 10:09 AM
- Invoicing Schedule for Jan-Dec 2021 Monthly and 2022 Annual CRR Auctions11/20/2020, 2:53 PM
Reliability Must Run (RMR)
Settlement information for the annual agreements between the ISO and qualified generators.
- RMR Invoice Template Version 3 (Effective Jun 1, 2013)06/12/2013, 11:04 AM
- Prior Period Examples and Guidelines09/03/2002, 1:37 PM
Reliability Must Run (RMR) reporting
- RMR Section 5.5 Report Template12/28/2010, 3:08 PM
- RMR Section 5.5 Report Procedures12/28/2010, 3:07 PM
Disputes
Submit a settlement dispute form in CIDI*
*For scheduling coordinators only
- Settlement Dispute Form09/12/2016, 11:45 AM
- Placeholder Dispute Form04/08/2009, 9:33 AM
Retroactive settlements
View previous retroactive settlement documentsCredit policy
The credit policy is detailed in the ISO Tariff and the Business Practice Manual for Credit Management and Market Clearing. Consistent with the policy, market participants use the following forms to demonstrate that they meet the ISO minimum participation and financial security requirements and to request an unsecured credit limit.
- California ISO Credit Management Frequently Asked Questions (FAQs)08/03/2023, 10:06 AM
- ISO Form Letter of Credit07/20/2023, 8:30 AM
- Officer Certification Form02/24/2022, 4:25 PM
- Credit Management - Congestion Revenue Rights Estimated Aggregate Liability Components and Data Flow12/23/2020, 9:51 AM
- Credit Management - Convergence Bidding Estimated Aggregate Liability Components and Data Flow12/23/2020, 9:51 AM
- ISO Unsecured Credit Application02/01/2017, 3:46 PM
- ISO Form Guaranty02/02/2011, 1:31 PM
The CIDI user guide is available on the application page.
If you are a scheduling coordinator and need access to settlement statements, invoices, ISO bill determinant files and SaMC configuration output files, visit the MRI-S application page for more information and the user guide.
- ISO Tariff05/18/2024, 7:42 PM
- ISO Tariff, Section 11 - California ISO Settlements and Billing01/16/2024, 9:51 AM
- Business Practice Manual for Credit Management and Market Clearing05/18/2024, 7:41 PM
- Business Practice Manual for Settlements and Billing05/18/2024, 7:41 PM