Loss factors

Loss factors are used to determine the transmission losses charges that apply to system access service under the following rates of the ISO tariff:

• Rate STS, Supply Transmission Service
• Rate XOS, Export Opportunity Service
• Rate IOS, Import Opportunity Service
• Rate DOS, Demand Opportunity Service

The AESO must establish and maintain loss factors in accordance with section 501.10 of the ISO rules, Transmission Loss Factors (the “Loss Factor Rule”). A new loss factor methodology was implemented in the Loss Factor Rule effective Jan. 1, 2017, reflecting decisions issued in Proceeding 790 of the Alberta Utilities Commission (“Commission”). The 2024 loss factors were initially established to become effective on January 1, 2024.

On August 30, 2024, the AESO posted adjusted loss factors to be effective on September 1, 2024, which will apply to system access services provided under Rates STS, XOS, IOS, and DOS of the ISO tariff. The adjusted loss factors reflect changes that have occurred to generating facilities included in the information used to initially establish loss factors for 2024, in accordance with subsection 2(4)(a) section 501.10 of the ISO rules, Transmission Loss Factors. The changes to generating facilities in 2024 Loss Factors were summarized in the stakeholder letter posted by the AESO on August 30, 2024.

• Letter to Stakeholders on adjustments to 2024 Loss Factors [Posted: Aug 30, 2024]

The initial and updated 2024 loss factors are provided here:

• 2024 loss factors effective 1 Jan 2024 – 31 Aug 2024 [Updated: May 17, 2024]
• 2024 loss factors effective 1 Sept. 2024 [Posted: Aug. 30, 2024]

The initial 2024 loss factors were posted on Oct. 2, 2023, in accordance with the requirements of the Loss Factor Rule. The posted loss factors were updated on Dec. 19, 2023, to include RPT1 and RPT2, on May 17, 2024 to include locations 0000013111 and 0000043411 as those locations had not satisfied project inclusion criteria when the 2024 loss factors were being determined. The average annual loss factor for the transmission system was therefore used for these locations in accordance with subsection 9(2) of the Loss Factor Rule. Changes to generating facilities were reflected in the adjusted 2024 loss factors that became effective on September 1, 2024, with the adjusted loss factors initially published on August 30, 2024.

In accordance with subsection 3(2) of the Loss Factor Rule, the AESO must provide additional information used to establish loss factors. The additional information used to establish the loss factors that became effective on September 1, 2024 is provided here:

• Hourly merit order data for 2024 loss factors (ZIP file, 16 MB) [Posted: Aug. 30, 2024]
• Sample of hourly load data for 2024 loss factors (ZIP file, 2 MB) [Posted: Aug. 30, 2024]
• Process for requesting access to system topologies [Posted: Oct. 2, 2023]
• Procedure to determine transmission system losses for loss factor calculations [Posted: Aug. 30, 2024]
• Software and scripts used to calculate hourly raw loss factors (ZIP file, 12 MB) [Posted: Aug. 30, 2024]
• Workbook showing calculations for 2024 loss factors (Microsoft Excel, 127 MB) [Posted: Aug. 30, 2024]

The additional information used to establish the loss factors that were effective from January 1, 2024 to August 31, 2024 is provided here:

• Hourly merit order data for 2024 loss factors (ZIP file, 17 MB) [Posted: Oct. 2, 2023]
• Sample of hourly load data for 2024 loss factors (ZIP file, 2 MB) [Posted: Oct. 2, 2023]
• Process for requesting access to system topologies [Posted: Oct. 2, 2023]
• Procedure to determine transmission system losses for loss factor calculations [Posted: Oct. 2, 2023]
• Software and scripts used to calculate hourly raw loss factors (ZIP file, 12 MB) [Posted: Oct. 2, 2023]
• Workbook showing calculations for 2024 loss factors (Microsoft Excel, 137 MB) [Updated: May 17, 2024] 

Anticipated losses on the transmission system are 2,021 GWh for 2024 and the average loss factor for the transmission system is 3.26% for 2024.

The calibration factor is a percentage adjustment that is added to or subtracted from every loss factor so that generating facilities and other services pay the actual (rather than forecast) cost of transmission losses. It applies to every loss factor for the system access services to which loss factors apply, in accordance with Rider E of the ISO tariff, Losses Calibration Factor Rider.

• Q1 2024 Rider E Estimate [Posted: Dec. 19, 2023]
• Q2 2024 Rider E Estimate [Posted: March 28, 2024]
• Q3 2024 Rider E Estimate [Posted: June 28, 2024]
• Q4 2024 Rider E Estimate [Posted: Oct. 1, 2024]

Loss factors are used to determine the transmission losses charges that apply to system access service under the following rates of the ISO tariff:

• Rate STS, Supply Transmission Service
• Rate XOS, Export Opportunity Service
• Rate IOS, Import Opportunity Service
• Rate DOS, Demand Opportunity Service

The AESO must establish and maintain loss factors in accordance with section 501.10 of the ISO rules, Transmission Loss Factors (the “Loss Factor Rule”). A new loss factor methodology was implemented in the Loss Factor Rule effective Jan. 1, 2017, reflecting decisions issued in Proceeding 790 of the Alberta Utilities Commission (“Commission”). The 2023 loss factors were initially established to be become effective on January 1, 2023.

On May 30, 2023, the AESO posted adjusted loss factors to be effective on June 1, 2023, which will apply to system access services provided under Rates STS, XOS, IOS, and DOS of the ISO tariff. The adjusted loss factors reflect changes that have occurred to generating facilities included in the information used to initially establish loss factors for 2023, in accordance with subsection 2(4)(a) section 501.10 of the ISO rules, Transmission Loss Factors. The changes on input to 2023 Loss Factors were summarized in the stakeholder letter posted by the AESO on May 30, 2023.

• Letter to Stakeholder on adjustments to 2023 Loss Factors [Posted: May 31, 2023]

The initial and updated 2023 loss factors are provided here:

• 2023 loss factors effective 1 Jan 2023 – 31 May 2023 [Updated: May 31, 2023]
• 2023 loss factors effective 1 Jun 2023 [Posted: May 31, 2023]

The initial 2023 loss factors were posted on Sept. 29, 2022, in accordance with the requirements of the Loss Factor Rule. The posted loss factors were updated on Oct. 7, 2022, to remove locations HHW1 and WHE1 as they were inadvertently added after already being included under their respective project numbers. The posted loss factors were updated on Dec. 8, 2022 to include 0000021311, 0000029711, and S24N as those locations had not satisfied project inclusion criteria when the 2023 loss factors were being determined. The average annual loss factor for the transmission system was therefore used for this location in accordance with subsection 9(2) of the Loss Factor Rule. Changes to generating facilities were reflected in the adjusted 2023 loss factors that became effective on June 1, 2023, with the adjusted loss factors initially published on May 30, 2023.

On April 11, the AESO advises market participants and other interested parties that it is investigating if an adjustment to loss factors established for 2023 under the Loss Factor Rule is required, with results expected to become available in May. If adjustment is required, the AESO expects the revised loss factors to be effective on June 1, 2023. 

• Letter to stakeholder on investigation of adjustment to 2023 Loss Factors [Posted: April, 11, 2023]

In accordance with subsection 3(2) of the Loss Factor Rule, the AESO must provide additional information used to establish loss factors. This additional information is provided here:

• Hourly merit order data for 2023 loss factors (ZIP file, 17 MB) [Posted: May 31, 2023]
• Sample of hourly load data for 2023 loss factors (ZIP file, 2 MB) [Posted: May 31, 2023]
• Process for requesting access to system topologies 
• Procedure to determine transmission system losses for loss factor calculations [Posted: May 31, 2023]
• Software and scripts used to calculate hourly raw loss factors (ZIP file, 3 MB) [Posted: May 31, 2023]
• Workbook showing calculations for 2023 loss factors (Microsoft Excel, 125 MB) [Posted: May 31, 2023]

The additional information used to establish the loss factors that were effective from January 1, 2023 to May 31, 2023 is provided here:

• Hourly merit order data for 2023 loss factors (ZIP file, 17 MB) [Posted: Sept. 29, 2022]
• Sample of hourly load data for 2023 loss factors (ZIP file, 2 MB) [Posted: Sept. 29, 2022]
• Process for requesting access to system topologies 
• Procedure to determine transmission system losses for loss factor calculations [Posted: Sept. 29, 2022]
• Software and scripts used to calculate hourly raw loss factors (ZIP file, 3 MB) [Posted: Sept. 29, 2022]
• Workbook showing calculations for 2023 loss factors (Microsoft Excel, 125 MB) [Posted: Dec. 8, 2022]

Anticipated losses on the transmission system are 1,914 GWh for 2023 and the average loss factor for the transmission system is 3.12% for 2023.

The AESO has published the list of locations which will be included in the loss factor calculations. Subsection 7 of the Loss Factor Rule governs which locations are to be included.

• Master Loss Factor Location List for 2023 [Posted: Aug 25, 2022]

The calibration factor is a percentage adjustment that is added to or subtracted from every loss factor so that generating facilities and other services pay the actual (rather than forecast) cost of transmission losses. It applies to every loss factor for the system access services to which loss factors apply, in accordance with Rider E of the ISO tariff, Losses Calibration Factor Rider.

• Q1 2023 Rider E Estimate [Posted: Dec. 16, 2022]
• Q2 2023 Rider E Estimate [Posted: March 31, 2023]
• Q3 2023 Rider E Estimate [Posted: June 29, 2023]
• Q4 2023 Rider E Estimate [Posted: Sept. 27, 2023]

Loss factors are used to determine the transmission losses charges that apply to system access service under the following rates of the ISO tariff:

• Rate STS, Supply Transmission Service
• Rate XOS, Export Opportunity Service
• Rate IOS, Import Opportunity Service
• Rate DOS, Demand Opportunity Service

The AESO must establish and maintain loss factors in accordance with section 501.10 of the ISO rules, Transmission Loss Factors (the “Loss Factor Rule”). A new loss factor methodology was implemented in the Loss Factor Rule effective Jan. 1, 2017, reflecting decisions issued in Proceeding 790 of the Alberta Utilities Commission (“Commission”). The 2022 loss factors are provided here:

• 2022 loss factors effective 1 Jan 2022 [Updated: Nov. 28, 2022]  

The initial 2022 loss factors were posted on Dec. 14, 2021, in accordance with the requirements of the Loss Factor Rule. The posted loss factors were updated on Feb. 28, 2022, to include location 332S040N on June 2, 2022, to include locations 311S089N, EPS1, JNR2, and JNR3, on July 6, 2022, to include location WHE1, on Aug. 10, 2022 to include locations CYP2 and HLD1, on Aug. 31, 2022 to include location HHW1, on Oct. 5, 2022 to include location JNR1, on Oct. 26, 2022 to include GRZ1 and LAN1, and on Nov. 28, 2022 to include 0000021311, 0000029711, and S24N as those locations had not satisfied project inclusion criteria when the 2022 loss factors were being determined. The average annual loss factor for the transmission system was therefore used for this location in accordance with subsection 9(2) of the Loss Factor Rule.

In accordance with subsection 3(2) of the Loss Factor Rule, the AESO must provide additional information used to establish loss factors. This additional information is provided here:

• Hourly merit order data for 2022 loss factors (ZIP file, 15 MB) [Updated: Dec. 13, 2021] 
• Sample of hourly load data for 2022 loss factors (ZIP file, 2 MB) [Updated: Dec. 13, 2021] 
• Process for requesting access to system topologies
• Procedure to determine transmission system losses for loss factor calculations [Posted: Nov. 30, 2020]
• Software and scripts used to calculate hourly raw loss factors (ZIP file, 91 MB) [Posted: Nov. 30, 2020]
• Workbook showing calculations for 2022 loss factors (Microsoft Excel, 112 MB) [Updated: Nov. 28, 2022] 

Anticipated losses on the transmission system are 1,895 GWh for 2022 and the average loss factor for the transmission system is 3.15% for 2022.

On Nov. 30, 2021, the AESO published loss factors for 2022, together with additional information used to establish the loss factors in accordance with section 501.10 of the ISO rules, Transmission Loss Factors. In late November, the AESO identified an error in the hour load data used in the calculations that could not be corrected prior to publishing. The corrected loss factors for 2022 are published above. The original Nov. 30, 2021 posting 2022 loss factors, which are not implemented in the billing process, are provided below along with additional information in accordance with subsection 3(2) of the Loss Factor Rule.

• 2022 loss factors effective 1 Jan 2022 [Posted: Nov. 30, 2021]
• Workbook showing calculations for 2021 loss factors (Microsoft Excel, 112 MB) [Posted: Nov. 30, 2021]
• Hourly merit order data for 2022 loss factors (ZIP file, 15 MB) [Posted: Nov. 30, 2021]
• Sample of hourly load data for 2022 loss factors (ZIP file, 2 MB) [Posted: Nov. 30, 2021]

The AESO has published the list of locations which will be included in the loss factor calculations. Subsection 7 of the Loss Factor Rule governs which locations are to be included.

• Master Location List Letter [Posted: Nov. 4, 2021]
• Master Loss Factor Location List for 2022 [Posted: Nov. 4, 2021]

The calibration factor is a percentage adjustment that is added to or subtracted from every loss factor so that generating facilities and other services pay the actual (rather than forecast) cost of transmission losses. It applies to every loss factor for the system access services to which loss factors apply, in accordance with Rider E of the ISO tariff, Losses Calibration Factor Rider. 

• Q1 2022 Rider E Estimate [Posted: Dec. 20, 2021]  
• Q2 2022 Rider E Estimate [Posted: March 31, 2022]  
• Q3 2022 Rider E Estimate [Posted: June 29, 2022]
• Q4 2022 Rider E Estimate [Posted: Sept. 28, 2022]  

Schedule of loss factor activities

The following schedule provides an overview and timing of future activities related to loss factors, as expected by the AESO at the time of posting. The AESO will update the schedule periodically to reflect anticipated changes to activities or timing.

• Loss Factor Work Activities (2019-05-31) [Posted: June 3, 2019]
• Loss Factor Work Activities (2018-12-20) [Posted: December 20, 2018]
• Loss Factor Work Activities (2018-09-24) [Posted: September 25, 2018]

Questions and responses

 The following document lists questions asked by stakeholders on activities related to loss factors. The AESO will update the log periodically to track new questions and to summarize responses as they become available. 

• Loss Factor Questions and Responses (2018-11-30) (Microsoft Excel) [Posted: November 30, 2018]

Technical meetings

The AESO holds technical meetings with stakeholders at appropriate points during its loss factor activities. The following documents relate to the technical meetings.

• AESO Corrected Loss Factors and True-Up Adjustments for 2012-2016 (2021-09-15) [Posted: September 15, 2021]
• AESO Corrected Loss Factors and True-Up Adjustments for 2011 (2021-09-03) [Posted: September 3, 2021]
• AESO Corrected Loss Factors and True-Up Adjustments for 2010 (2021-09-01) [Posted: September 1, 2021]
• AESO Corrections to Adjusted 2021 Loss Factors (2021-08-23) [Posted: August 23, 2021]
• AESO Corrected Loss Factors and True-Up Adjustments for 2009 (2021-08-13) [Posted: August 13, 2021]
• AESO Corrected Loss Factors and True-Up Adjustments for 2007 and 2008 (2021-08-06) [Posted: August 6, 2021]
• AESO Delay in Publishing Adjustments to 2021 Loss Factors (2021-07-29) [Posted: July 29, 2021] 
• AESO Corrected Loss Factors and True-Up Adjustments for 2006 (2021-07-28) [Posted: July 28, 2021]
• AESO Update on Loss Factor Activities Under Module C (2021-06-28) [Posted: June 28, 2021]
• AESO Planned Adjustments to 2021 Loss Factors (2021-06-23) [Posted: June 23, 2021]
• AESO Update on Loss Factor Activities Under Module C (2021-04-01) [Posted: April 1, 2021]
• AESO Presentation for Technical Meeting on Loss Factor Activities (2021-02-17) [Updated as delivered: February 17, 2021]
• AESO Invitation and Draft Agenda for Technical Meeting on Loss Factor Activities (2021-02-03) [Posted: February 3, 2021]
• AESO Presentation for Technical Meeting on Loss Factor Activities (2020-11-20) [Updated as delivered: November 20, 2020]
• Stakeholder Feedback on AESO Intent to Request Guidance on Module C Interest Calculation (2020-11-13) [Posted: November 13, 2020]
• AESO Intent to Request Guidance on Module C Interest Calculation (2020-11-03) [Posted: November 3, 2020]
• AESO Invitation and Draft Agenda for Technical Meeting on Loss Factor Activities (2020-11-03) [Posted: November 3, 2020]
• AESO Updates to Module C Adjustments (2020-10-15) [Posted: Oct 15, 2020]
• AESO Presentation for Technical Meeting on Loss Factor Activities (2020-07-15) [Updated as delivered: July 16, 2020] 
• AESO Invitation and Draft Agenda for Loss Factor Technical Meeting on Module C Activities (2020-06-22) [Posted: June 22, 2020]
• Changes to Export and Import Loss Factors for Alberta-British Columbia Intertie (2020-05-05) [Posted: May 5, 2020]
• AESO Presentation for Technical Meeting on Loss Factor Activities (2019-12-13) [Posted: December 16, 2019]
• AESO Invitation to Technical Meeting on Loss Factors Activities (2019-12-03) [Posted: December 3, 2019]
• AESO Update on Loss Factor Activities (2019-09-17) [Posted: September 17, 2019]
• AESO Presentation for Technical Meeting on Loss Factor Activities (2019-07-24) [Posted: July 24, 2019]
• AESO Invitation to Technical Meeting on Loss Factors Activities (2019-07-11) [Posted: July 11, 2019]
• AESO Update on Loss Factor Activities (2019-05-16) [Posted: May 16, 2019]
• AESO Presentation for Technical Meeting on Loss Factor Activities (2018-12-13) [Posted: December 18, 2018]
• AESO Invitation to Technical Meeting on Loss Factors Activities (2018-11-29) [Posted: November 29, 2018]
• AESO Presentation for Technical Meeting on Loss Factor Activities (2018-10-17) [Posted: October 18, 2018]
• AESO Invitation to Technical Meeting on Loss Factor Activities (2018-10-02) [Posted: October 2, 2018]
• Module C Compliance Filing Technical Meeting - Presentation (2018-02-08)
• AESO Invitation to Technical Meeting to Discuss Compliance Filing in Response to Decision 790-D06-2017 on Module C Matters (2018-01-19)

Additional information

In support of the stakeholder engagement information provided above, the AESO provides the following additional information, which reflects the AESO’s expectations at the time of posting.

• Master Loss Factor Location List for 2019 (2019-06-28) (Microsoft Excel, 52 KB) [Posted: June 28, 2019]
• Master Loss Factor Location List for 2019 (2018-10-04) (Microsoft Excel, 50 KB) [Posted: October 4, 2018]

Commission Proceeding 790

A new loss factor methodology has been determined through Commission Proceeding 790. Related documents filed with the Commission are accessible through the eFiling System on the Commission’s website in Proceeding 790, Milner Power Inc. Complaint Against the ISO Line Loss Rule. Note that, to access documents in Proceeding 790, you must open an eFiling System user account and log in. The following exhibits in Proceeding 790 are particularly relevant to the implementation of the new methodology:

• Alberta Utilities Commission Decision 790-D03-2015 Complaints regarding the ISO Transmission Loss Factor Rule and Loss Factor Methodology
• Exhibit 790-X0452, AESO Implementation Plan to Develop a Revised Loss Factor Rule in Compliance With Decision 790-D03-2015 (filed February 1, 2016)
• Exhibit 790-X0467, Commission Ruling on AESO Implementation Plan and Response to Clarification Requests (released March 18, 2015)
• Exhibit 790-X0469, AESO Q1 2016 Update on Implementation Plan (filed April 1, 2016)
• Exhibit 790-X0474, AESO Q2 2016 Update on Implementation Plan (filed July 15, 2016)
• Exhibit 790-X0472, AESO Q2 2016 Update - Appendix - Shift Factor Example Excel Workbook (filed July 15, 2016)
• Exhibit 790-X0475, AESO Compliance Filing in Response to Decision 790-D03-2015 (filed August 31, 2016)
• Exhibit 790-X0496, Availability of the Topology Cases and Timing of the AESO Q3 Update (filed September 29, 2016)
• AESO Q1 2017 Update on Implementation Plan in Module B (filed March 30, 2017)

Earlier postings of 2018 loss factors

The AESO initially posted 2018 loss factors on Mar 22, 2018, and subsequently identified inconsistencies in some of the data used in the 2018 loss factor calculations. Therefore, those loss factors were not implemented to determine transmission losses charges. The 2018 loss factors were recalculated and are republished in the 2018 loss factors section above. The originally posted information will remain available below for the interest of market participants.

• 2018 loss factors effective 1 Jan 2018 [Posted: Mar 22, 2018 - not implemented]
• Hourly merit order data for 2018 loss factors (ZIP file, 15 MB) [Posted: Mar 22, 2018]
• Sample of hourly load data for 2018 loss factors (ZIP file, 4 MB) [Posted: Mar 22, 2018]
• Procedure to determine transmission system losses for loss factor calculations [Posted: Mar 22, 2018]
• Software and scripts used to calculate hourly raw loss factors (ZIP file, 124 MB) [Posted: Mar 22, 2018]
• Workbook showing calculations for 2018 loss factors (Microsoft Excel, 82 MB) [Posted: Mar 22, 2018]

Earlier postings of 2017 loss factors

The AESO initially posted 2017 loss factors on May 11, 2017, July 13, 2017, and September 12, 2017, and subsequently identified concerns with certain aspects of those posted 2017 loss factors. Therefore, those loss factors were not implemented to determine transmission losses charges. The 2017 loss factors were recalculated and are republished in the 2017 loss factors section above. The originally posted information will remain available below for the interest of market participants.

• 2017 loss factors effective 1 Jan 2017 [Posted: September 12, 2017 - not implemented]     
• Hourly merit order data for 2017 loss factors (ZIP file, 15 MB) [Posted: September 12, 2017
• Sample of hourly load data for 2017 loss factors (ZIP file, 2 MB) [Posted: September 12, 2017
• Procedure to determine transmission system losses for loss factor calculations [Posted: September 12, 2017]     
• Software and scripts used to calculate hourly raw loss factors (ZIP file, 97 MB) [Posted: September 12, 2017
• Workbook showing calculations for 2017 loss factors (Microsoft Excel, 87 MB) [Posted: September 12, 2017]     
• Delay in Implementation of Recalculated 2017 Loss Factors Published on September 12, 2017 [Posted: October 2, 2017]
• Summary of Changes Included in Recalculated 2017 Loss Factors Published on September 12, 2017 [Posted: September 18, 2017]
• 2017 loss factors effective 1 Jan 2017 [Posted: July 13, 2017 - not implemented]
• Hourly merit order data for 2017 loss factors (ZIP file, 17 MB) [Posted: July 6, 2017]
• Sample of hourly load data for 2017 loss factors (ZIP file, 1.9 MB) [Posted: July 6, 2017]
• Procedure to determine transmission system losses for loss factor calculations [Posted: July 6, 2017]
• Software and scripts used to calculate hourly raw loss factors (ZIP file, 96 MB) [Posted: July 13, 2017]
• Workbook showing calculations for 2017 loss factors (Microsoft Excel, 78 MB) [Posted: July 13, 2017]
• Summary of Changes Included in Recalculated 2017 Loss Factors Published on July 13, 2017 [Posted: July 13, 2017]
• 2017 loss factors effective 1 Jan 2017 [Posted: May 11, 2017 - not implemented]
• Hourly merit order data for 2017 loss factors (ZIP file, 16 MB) [Posted: May 11, 2017]
• Sample of hourly load data for 2017 loss factors (ZIP file, 2.9 MB) [Posted: May 11, 2017]
• Procedure to determine transmission system losses for loss factor calculations [Posted: May 11, 2017]
• Software and scripts used to calculate hourly raw loss factors (ZIP file, 112 MB) [Posted: May 11, 2017]
• Workbook showing calculations for 2017 loss factors (Microsoft Excel, 85 MB) [Posted: May 11, 2017]

Technical Meetings

In its Q1 2016 Update on Implementation Plan document, the AESO indicated it would hold technical meetings with stakeholders at appropriate points during the implementation activities. The following documents relate to the technical meetings:

• AESO Presentation for Technical Meeting on Loss Factors Activities (2018-07-26)
• AESO Invitation to Technical Meeting on Loss Factors Activities (2018-07-10)
• AESO Presentation for Recalculated 2018 Loss Factors Technical Meeting (2018-04-27)
• AESO Invitation to Recalculated 2018 Loss Factors Technical Meeting (2018-04-10)
• AESO Presentation for 2018 Loss Factors Technical Meeting (2018-03-27)
• AESO Invitation to 2018 Loss Factors Technical Meeting (2018-03-14)
• AESO Presentation for Recalculated 2017 Loss Factors Technical Meeting (2017-09-14)
• AESO Invitation to Recalculated 2017 Loss Factors Technical Meeting (2017-08-31)
• AESO Presentation for 2017 Loss Factors Technical Meeting (2017-05-17)
• AESO Invitation to 2017 Loss Factors Technical Meeting (2017-05-09)
• AESO Presentation to Discuss Options to Calculate Loss Factors for 2006 to 2010 (2016-10-13)
• AESO Invitation to Meeting to Discuss Options to Calculate Loss Factors for 2006 to 2010 (2016-09-22)
• AESO Presentation for Loss Factor Implementation Technical Meeting (2016-06-07)
• AESO Invitation to Meeting re Certain Aspects of Implementation of Loss (2016-05-24)

Initial Input Data for Calculation of 2017 Loss Factors

In its Implementation Plan, the AESO indicated that it would post the following information on its website:

• 2016-04-12 Notes on Load Input Data Sample
• 2016-04-12 Load Input Data Sample (Excel, 2 MB)
• 2016-04-11 Notes on Energy Market Merit Order Input Data
• 2016-04-11 2015 Energy Market Merit Order Input Data (Single Annual File) (ZIP File, 39 MB)
• 2016-04-11 2015 Energy Market Merit Order Input Data (Twelve Monthly Files) (ZIP File, 39 MB)

As part of Proceeding 790, the Alberta Utilities Commission (“Commission”) has directed the AESO to recalculate loss factors for the historical period from January 1, 2006 to December 31, 2016 using the methodology first implemented for 2017. The process to recalculate loss factors includes market participant consultation, compliance filings, and the posting of recalculated loss factors as they become available.

Commission Proceeding 790 - Module C

The following decisions are particularly relevant to the recalculation of loss factors for 2006-2016:

• Alberta Utilities Commission Decision 790-D06-2017, Complaints Regarding the ISO Transmission Loss Factor Rule and Loss Factor Methodology – Phase 2 Module C, issued December 18, 2017
• Alberta Utilities Commission Decision 790-D04-2016, Complaints Regarding the ISO Transmission Loss Factor Rule and Loss Factor Methodology – Phase 2 Module C – Preliminary Issues, issued September 28, 2016

Module C Adjustment Charges and Refunds

The Alberta Utilities Commission decisions in Proceeding 790 - Module C result in adjustments to the losses charges and credits that were initially billed during the historical period from January 1, 2006 to December 31, 2016. In accordance with Decision 25150-D02-2020, these adjustments will be financially settled with market participants after calculations have been completed for three periods: from 2016 back to 2014, from 2013 back to 2010, and from 2009 back to 2006. In the workbooks below, adjustments are estimated for each year from 2016 back to 2006 as they become available and are summarized cumulatively for each of the three periods.

The process that will be followed to financially settle the Module C adjustments and the currently expected schedule for that process are provided in the Module C Settlement Procedure document below.

• Module C Settlement Procedure (2021-08-06) [Updated: Aug 6, 2021]

On June 28, 2021, the AESO advised market participants and other interested parties that it is in the process of correcting a small number of errors identified in system topologies used for Module C and has begun to recalculate the Module C loss factors for all years from 2006 to 2016 to reflect the corrections. The AESO expects to complete the recalculation of Module C loss factors for all years in August 2021, with the resulting adjustments financially settled in the fourth quarter of 2021 in conjunction with the Module C “true-up” settlement process described in the Module C Settlement Procedure document posted above. For more information, see the update posted in the stakeholder engagement section here.

The workbooks below provide Module C recalculated charge, credit, and refund amounts reflecting the AESO’s best estimates at the time of preparation; those amounts may change in preliminary or final statements if volume or price adjustments occur prior to statements being issued.

True-up settlement including correction of system topology errors (2006-2016, cash settlement on Dec 30, 2021):

• Estimated Module C True-Up Adjustments - Summary 2006-2016 (2021-09-20) (Excel, 1.5 MB) [Updated: Sep 20, 2021] 
• Estimated Module C True-Up Adjustments - 2006 (2021-09-20) (Excel, 1.2 MB) [Updated: Sep 20, 2021]
• Estimated Module C True-Up Adjustments - 2007 (2021-08-06) (Excel, 1.2 MB) [Posted: Aug 6, 2021]
• Estimated Module C True-Up Adjustments - 2008 (2021-08-06) (Excel, 1.2 MB) [Posted: Aug 6, 2021]
• Estimated Module C True-Up Adjustments - 2009 (2021-08-13) (Excel, 1.2 MB) [Posted: Aug 13, 2021]
• Estimated Module C True-Up Adjustments - 2010 (2021-09-01) (Excel, 0.7 MB) [Posted: Sep 1, 2021]
• Estimated Module C True-Up Adjustments - 2011 (2021-09-03) (Excel, 0.7 MB) [Posted: Sep 3, 2021]   
• Estimated Module C True-Up Adjustments - 2012 (2021-09-08) (Excel, 0.7 MB) [Posted: Sep 8, 2021]  
• Estimated Module C True-Up Adjustments - 2013 (2021-09-08) (Excel, 0.7 MB) [Posted: Sep 8, 2021]
• Estimated Module C True-Up Adjustments - 2014 (2021-09-09) (Excel, 0.7 MB) [Posted: Sep 9, 2021]
• Estimated Module C True-Up Adjustments - 2015 (2021-09-13) (Excel, 0.8 MB) [Posted: Sep 13, 2021] 
• Estimated Module C True-Up Adjustments - 2016 (2021-09-13) (Excel, 0.8 MB) [Posted: Sep 13, 2021]    

First settlement period (2016-2014, cash settlement on Dec 30, 2020):

• Estimated Module C Adjustments - Summary 2016-2014 (2020-10-19) (Excel, 0.4 MB) [Updated: Oct 19, 2020]
• Estimated Module C Adjustments - 2016 (2020-10-19) (Excel, 0.3 MB) [Updated: Oct 19, 2020]
• Estimated Module C Adjustments - 2015 (2020-10-19) (Excel, 0.3 MB) [Updated: Oct 19, 2020]
• Estimated Module C Adjustments - 2014 (2020-10-19) (Excel, 0.3 MB) [Updated: Oct 19, 2020]

Second settlement period (2013-2010, cash settlement on Mar 1, 2021):

• Estimated Module C Adjustments - Summary 2013-2010 (2020-12-14) (Excel, 0.4 MB) [Updated: Dec 14, 2020]
• Estimated Module C Adjustments - 2013 (2020-11-19) (Excel, 0.3 MB) [Posted: Nov 19, 2020]
• Estimated Module C Adjustments - 2012 (2020-11-25) (Excel, 0.3 MB) [Posted: Nov 25, 2020]
• Estimated Module C Adjustments - 2011 (2020-12-01) (Excel, 0.3 MB) [Updated: Dec 1, 2020]
• Estimated Module C Adjustments - 2010 (2020-12-14) (Excel, 0.3 MB) [Updated: Dec 14, 2020]

Third settlement period (2009-2006, cash settlement on May 31, 2021):

• Estimated Module C Adjustments - Summary 2009-2006 (2021-01-29) (Excel, 0.4MB) [Posted: Jan 29, 2021]
• Estimated Module C Adjustments - 2009 (2020-12-21) (Excel, 0.3 MB) [Posted: Dec 21, 2020]
• Estimated Module C Adjustments - 2008 (2020-12-21) (Excel, 0.3 MB) [Posted: Dec 21, 2020]
• Estimated Module C Adjustments - 2007 (2021-01-26) (Excel, 0.3 MB) [Posted: Jan 26, 2021]
• Estimated Module C Adjustments - 2006 (2021-01-29) (Excel, 0.3 MB) [Posted: Jan 29, 2021]

Recalculated loss factors

The AESO is recalculating loss factors for each year from 2016 back to 2006 in accordance with the Alberta Utilities Commission decisions referenced above. The loss factors and additional information used to establish them are published for each year as they become available.

• 2016 recalculated loss factors
• 2015 recalculated loss factors
• 2014 recalculated loss factors
• 2013 recalculated loss factors
• 2012 recalculated loss factors
• 2011 recalculated loss factors
• 2010 recalculated loss factors
• 2009 recalculated loss factors
• 2008 recalculated loss factors
• 2007 recalculated loss factors
• 2006 recalculated loss factors

Financial security in relation to the Module C resettlement process

The AESO’s financial security requirements are set forth in ISO Rule 103.3 and are applicable to all market participants. Pursuant to ISO Rule 103.3, the AESO must calculate a market participant’s financial obligations, and a market participant must then provide and maintain financial security equal to or greater than the sum of its financial obligation minus any unsecured credit limit granted to the market participant as determined in accordance with this rule. The AESO is unable to exercise its discretion under ISO Rule 103.3 to waive the requirements set forth therein. In the case of a contravention of an ISO Rule, the AESO is obligated to report these to the Market Surveillance Administrator (“MSA”), who would then ultimately be responsible for enforcing the ISO Rules.

The AESO has reviewed this requirement in light of Module C, which will result in adjustments to the loss charges and credits that were initially billed during the historical period from January 1, 2006 to December 31, 2016. Given the unique circumstances of this resettlement for the historical period noted above, the AESO does not believe it to be in the public interest for the AESO to calculate, and for market participants to provide and maintain, additional financial security. The AESO also recognizes the importance of minimizing regulatory burden and costs to market participants given the current economic climate. The AESO therefore requested forbearance from the MSA regarding the enforcement of ISO Rule 103.3, solely as it relates to any adjustments arising from Module C.

The MSA has recently granted the AESO’s request and the terms of the MSA’s forbearance can be viewed here. Provided the MSA’s forbearance remains in effect, the AESO will not be requesting any additional financial security from market participants relating to adjustments arising from Module C.

Module C Payment Plan

In accordance with decisions of the Alberta Utilities Commission in Proceeding 790 – Module C, the AESO developed and received approval of a payment plan to mitigate the risk that a Module C settlement invoice would compromise an eligible party’s financial stability. Eligible parties who are approved to participate in the payment plan would repay a Module C settlement invoice over a 24-month term, including interest and fees.

An eligible party may apply to participate in the payment plan by completing an Application for Loss Factor Payment Plan Participation. The completed application form must be submitted by email to Nicole.Kinch@aeso.ca within 5 business days of the issuance of a preliminary Module C settlement statement.

The Module C payment plan application instructions and forms are provided below.

• Module C Payment Plan (Appendix A) [Posted: Sep 25, 2020]
• Application for Loss Factor Payment Plan Participation (Appendix A.1) (Microsoft Word) [Posted: Sep 25, 2020]
• Form of Credit Agreement (Appendix A.2) (Microsoft Word) [Posted: Sep 25, 2020]

Requests for additional information may be submitted to Nicole Kinch, AESO Accounting department, email Nicole.Kinch@aeso.ca or phone 403-539-2532.

The AESO determines loss factors annually and the calibration factor quarterly. View prior versions.

For market participants evaluating multiple generation sites or plant sizes, a preliminary loss factor application along with a non-refundable fee must be submitted for each preliminary loss factor requested (see section 4, subsection 4(3) of the AESO tariff).

Read about transmission loss factor methodology and requirements here:

Section 501.10 of the ISO rules, Transmission Loss Factor Methodology and Requirements

View information on the losses calibration factor rider here:

Rider E of the ISO tariff, Losses Calibration Factor Rider

From 2006 to 2016, the AESO determined loss factors through a 50% Area Load Methodology Using Corrected Loss Matrix.

Read documents related to the development and implementation of that methodology.