Previous loss factors and calibration factors

2021 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 January 1, 2017, reflecting decisions issued in Proceeding 790 of the Alberta Utilities Commission (“Commission”). The 2021 loss factors were initially established to become effective on January 1, 2021.

On June 23, 2021, the AESO advised market participants and other interested parties that loss factors established for 2021 would be adjusted under the Loss Factor Rule. More information is available in the update posted in the stakeholder engagement section here. The updated 2021 loss factors became effective on August 1, 2021.

The initial and updated 2021 loss factors are provided here.

• 2021 loss factors effective 1 Jan 2021 – 31 Jul 2021 [Updated: Aug 4, 2021]
• 2021 loss factors effective 1 Aug 2021 [Updated: Dec. 13, 2021]

The initial 2021 loss factors were posted on November 30, 2020 in accordance with the requirements of the Loss Factor Rule. The posted loss factors were updated on January 21, 2021 to include location SET1 and on May 28, 2021 to include locations 0000042111 and 0000052611, as neither location had satisfied project inclusion criteria when the 2021 loss factors were being determined. The average annual loss factor for the transmission system was therefore used for each location in accordance with subsection 9(2) of the Loss Factor Rule. The posted loss factors were also updated on May 28, 2021 to reflect the connection of Projects 1849 and 2241 downstream of a single system access service rather than in the original configuration of separate reversing POD locations. Changes to generating facilities were reflected in the adjusted 2021 loss factors that became effective on August 1, 2021, with the adjusted loss factors initially published on August 4, 2021, and subsequently corrected to address a small number of implementation errors on August 27, 2021. The posted loss factors were updated on September 28, 2021 to include location 0000006811, on November 29, 2021 to include location 0000023511, and on December 13, 2021 to include location 0000044711, as those locations had not satisfied project inclusion criteria when the 2021 loss factors were being adjusted. The average annual loss factor for the transmission system was therefore used for those locations with subsequent annual shifting and compression, in accordance with subsections 9(2), 9(3), and 11 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. The additional information used to establish the loss factors that became effective on August 1, 2021 is provided here:

• Hourly merit order data for 2021 loss factors (ZIP file, 15 MB) [Corrected: Aug 27, 2021]
• Sample of hourly load data for 2020 loss factors (ZIP file, 2 MB) [Posted: Aug 5, 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 2021 loss factors (Microsoft Excel, 102 MB) [Updated: Dec. 13, 2021]

The additional information used to establish the loss factors that were effective from January 1, 2021 to July 31, 2021 is provided here:

• Hourly merit order data for 2021 loss factors (ZIP file, 15 MB) [Posted: Nov 3, 2020]
• Sample of hourly load data for 2020 loss factors (ZIP file, 2 MB) [Posted: Nov 30, 2020]
• 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 2021 loss factors (Microsoft Excel, 99 MB) [Updated: Sep 28, 2021]

Anticipated losses on the transmission system are 1,889 GWh for 2021 and the average loss factor for the transmission system is 2.87% for 2021.

2021 Calibration factors

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 2021 Rider E Estimate [Posted: Dec. 21, 2020]
• Q2 2021 Rider E Estimate [Posted: March 30, 2021]
• Q3 2021 Rider E Estimate [Posted: June 29, 2021]
• Q4 2021 Rider E Estimate [Posted: Sept. 27, 2021]

2020 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 January 1, 2017, reflecting decisions issued in Proceeding 790 of the Alberta Utilities Commission (“Commission”). The 2020 loss factors are provided here: 

• 2020 loss factors effective 1 Jan 2020 [Posted: Oct 29, 2020]     

2020 loss factors were initially posted on November 21, 2019 in accordance with the requirements of the Loss Factor Rule. The posted loss factors were updated on January 29, 2020 to include location 0000019811, on July 31, 2020 to include location PMB1, on September 29, 2020 to include locations 0000033111 and 312S008N, and on October 29, 2020 to include location SUM1, as neither location had satisfied project inclusion criteria when the 2020 loss factors were being determined. The average annual loss factor for the transmission system is therefore used for each location in accordance with subsection 9(2) of the Loss Factor Rule. The posted loss factors were also updated on May 5, 2020 to correct the export and import loss factors for the Alberta-British Columbia intertie.

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 2020 loss factors (ZIP file, 13 MB) [Posted: Nov 21, 2019]
• Sample of hourly load data for 2020 loss factors (ZIP file, 4 MB) [Posted: Mar 5, 2020]
• Process for requesting access to system topologies  
• Procedure to determine transmission system losses for loss factor calculations [Posted: Nov 21, 2019]
• Software and scripts used to calculate hourly raw loss factors (ZIP file, 259 MB) [Posted: Mar 5, 2020]
• Workbook showing calculations for 2020 loss factors (Microsoft Excel, 91 MB) [Posted: Oct 29, 2020] 

Anticipated losses on the transmission system are 1,870 GWh for 2020 and the average loss factor for the transmission system is 2.85% for 2020.

2020 Calibration factors

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 2020 Rider E Estimate [Posted: Dec. 17, 2019]
• Q2 2020 Rider E Estimate [Posted: March 30, 2020]
• Q3 2020 Rider E Estimate [Posted: June 29, 2020]
• Q4 2020 Rider E Estimate [Posted: Sept. 30, 2020]

2019 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 January 1, 2017, reflecting decisions issued in Proceeding 790 of the Alberta Utilities Commission (“Commission”). The 2019 loss factors are provided here:

• 2019 loss factors effective 1 Jan 2019 [Posted: May 5, 2020]

Due to unanticipated issues while preparing the input data for and updating the software for the 2019 loss factor calculations, the AESO was unable to publish 2019 loss factors until June 27, 2019. The AESO requested forbearance from the Market Surveillance Administrator (MSA) in respect of any related non-compliance with the Loss Factor Rule. The AESO subsequently identified a data misalignment resulting from certain files reflecting daylight saving time while all other files reflected standard time, and recalculated and posted corrected 2019 loss factors on July 16, 2019.

The posted loss factors were updated on February 4, 2020 to include location 312S025N, which did not satisfy project inclusion criteria when the 2019 loss factors were being determined and for which the average annual loss factor for the transmission system will therefore be used in accordance with subsection 9(2) of the Loss Factor Rule. The posted loss factors were further updated on May 5, 2020 to correct the export and import loss factors for the Alberta-British Columbia intertie.

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 2019 loss factors (ZIP file, 13 MB) [Posted: July 16, 2019]
• Sample of hourly load data for 2019 loss factors (ZIP file, 3 MB) [Posted: July 16, 2019]
• Process for requesting access to system topologies 
• Procedure to determine transmission system losses for loss factor calculations [Posted: June 27, 2019]
• Software and scripts used to calculate hourly raw loss factors (ZIP file, 143 MB) [Posted: July 16, 2019]
• Workbook showing calculations for 2019 loss factors (Microsoft Excel, 88 MB) [Posted: May 5, 2020]

Anticipated losses on the transmission system are 1,784 GWh for 2019 and the average loss factor for the transmission system is 2.75% for 2019.

2018 calibration factors

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 2019 Rider E Estimate [Posted: December 19, 2018]
• Q2 2019 Rider E Estimate [Posted: March 28, 2019]
• Q3 2019 Rider E Estimate [Posted: June 28, 2019]
• Q4 2019 Rider E Estimate [Posted: September 26, 2019]

2018 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 January 1, 2017, reflecting decisions issued in Proceeding 790 of the Alberta Utilities Commission (“Commission”). After the publication of the 2018 loss factors, the AESO implemented revisions to its loss factor calculation software that were applied in 2019 to recalculate 2018 loss factors. The posted loss factors were further updated on Jul 30, 2020 to correct the export and import loss factors for the Alberta-British Columbia intertie. The recalculated 2018 loss factors are provided here:

• 2018 loss factors effective 1 Jan 2018 [Posted: Jul 30, 2020] 

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 2018 loss factors (ZIP file, 15 MB) [Posted: Dec 31, 2019]
• Sample of hourly load data for 2018 loss factors (ZIP file, 4 MB) [Posted: Dec 31, 2019]
• Process for requesting access to system topologies
• Procedure to determine transmission system losses for loss factor calculations [Posted: Dec 31, 2019]
• Software and scripts used to calculate hourly raw loss factors (ZIP file,124 MB)[Posted: Dec 31, 2019]
• Workbook showing calculations for 2018 loss factors (Microsoft Excel, 84 MB) [Posted: Jul 30, 2020] 

Anticipated losses on the transmission system are 2,248 GWh for 2018 and the average loss factor for the transmission system is 3.61% for 2018.

Previously published 2018 loss factors

The AESO provides the previously published 2018 loss factors below for the reference of market participants.

In late 2017, the AESO consulted on revisions to the requirements for system topologies included in the Loss Factor Rule. To allow completion of the consultation process, the AESO requested and received forbearance from the Market Surveillance Administrator (MSA) in respect of any related non-compliance with the Loss Factor Rule. Please refer to the November 24, 2017 letter posted on the MSA website.

The AESO encountered unanticipated complexity in preparing the 2016 energy market merit order data required for the 2018 loss factor calculations. The AESO accordingly requested further forbearance from the MSA in anticipation of publishing 2018 loss factors no later than the end of March, 2018.

• 2018 loss factors effective 1 Jan 2018 [Posted: Dec 31, 2019]
• Workbook showing calculations for 2018 loss factors (Microsoft Excel, 82 MB) [Posted: Dec 31, 2019]
• 2018 loss factors effective 1 Jan 2018 [Posted: Apr 24, 2018]
• Hourly merit order data for 2018 loss factors (ZIP file, 15 MB)
• Sample of hourly load data for 2018 loss factors (ZIP file, 4 MB)
• Process for requesting access to system topologies
• Procedure to determine transmission system losses for loss factor calculations
• Software and scripts used to calculate hourly raw loss factors (ZIP file,124 MB)
• Workbook showing calculations for 2018 loss factors (Microsoft Excel, 82 MB)

2018 calibration factors

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.

• Q4 2018 Rider E Estimate [Posted: September 28, 2018]
• Q3 2018 Rider E Estimate [Posted: June 29, 2018]
• Q2 2018 Rider E Estimate [Posted: March 29, 2018]
• Q1 2018 Rider E Estimate [Posted: December 20, 2017]

2017 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 January 1, 2017, reflecting decisions issued in Proceeding 790 of the Alberta Utilities Commission (“Commission”). After the publication of the 2017 loss factors, the AESO implemented revisions to its loss factor calculation software that were applied in 2020 to recalculate 2017 loss factors. The posted loss factors were further updated on Jul 30, 2020 to correct the export and import loss factors for the Alberta-British Columbia intertie. The recalculated 2017 loss factors are provided here:

• 2017 loss factors effective 1 Jan 2017 [Posted: Jul 30, 2020] 

 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 2017 loss factors (ZIP file, 15 MB) [Posted: Mar 31, 2020] 
• Sample of hourly load data for 2017 loss factors (ZIP file, 3 MB) [Posted: Mar 31, 2020]
• Process for requesting access to system topologies
• Procedure to determine transmission system losses for loss factor calculations [Posted: Mar 31, 2020]
• Software and scripts used to calculate hourly raw loss factors (ZIP file, 258 MB) [Posted: Mar 31, 2020] 
• Workbook showing calculations for 2017 loss factors (Microsoft Excel, 84 MB) [Posted: Jul 30, 2020]

Anticipated losses on the transmission system are 2,230 GWh for 2017 and the average loss factor for the transmission system is 3.60% for 2017.

Previously published 2017 loss factors

The AESO provides the previously published 2017 loss factors and additional information for the reference of market participants:

• 2017 loss factors effective 1 Jan 2017 [Posted: Mar 31, 2020]
• Workbook showing calculations for 2017 loss factors (Microsoft Excel, 84 MB) [Posted: Mar 31, 2020]
• 2017 loss factors effective 1 Jan 2017 [Posted: Oct 31, 2017]
• Hourly merit order data for 2017 loss factors (ZIP file,  15 MB) [Posted: Oct 31, 2017]
• Sample of hourly load data for 2017 loss factors (ZIP file, 2 MB) [Posted: Oct 31, 2017]
• Process for requesting access to system topologies
• Procedure to determine transmission system losses for loss factor calculations
• Software and scripts used to calculate hourly raw loss factors(ZIP file,  97 MB) [Posted: Oct 31, 2017]
• Workbook showing calculations for 2017 loss factors (Microsoft Excel, 87 MB) [Posted: Oct 31, 2017]

2017 calibration factors

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.

• Q4 2017 Rider E Estimate [Posted: September 29, 2017]
• Q3 2017 Rider E Estimate [Posted: June 29, 2017]
• Q2 2017 Rider E Estimate [Posted: March 30, 2017]
• Q1 2017 Rider E Estimate [Posted: December 20, 2016]

• Q4 2016 Rider E Estimate [Posted: September 30, 2016]

• Q3 2016 Rider E Estimate [Posted: June 28, 2016]

• Q2 2016 Rider E Estimate [Posted: March 31, 2016]

• Q1 2016 Rider E Estimate [Posted: December 16, 2015]

2015 loss factors 

In accordance with section 32 of the Transmission Regulation, the AESO must make loss factors available to the public for a generating unit proposed to be constructed in Alberta. Updated information relating to the loss factors for some existing services may become available from time to time. The loss factors for the new services, as well as the updated information for existing services, are provided here:

Loss factors for new services and updated loss factors for existing services

For additional context, System Average Losses for 2016 have been estimated at 3.84%, compared to System Average Losses for 2015 of 3.66%.

Note that the AESO has requested and received forbearance from the Market Surveillance Administrator (MSA) in respect of any related non-compliance with Section 501.10 of the ISO rules, Transmission Loss Factor Methodology and Requirements. Please refer to the November 6, 2015 letter posted on the MSA website.

• Changes to 2015 Loss Factors Due to Updated Project Information by April 30, 2015 [Posted: May 29, 2015] 
• Changes to 2014 and 2015 Loss Factors Due to Updated Project Information [Posted: January 26, 2015] 
• Updated 2015 Final Loss Factors [Posted: December 19, 2014] 
• RFL 2015 [Posted: December 1, 2014] 
• All Bus LF 2015 [Posted: December 1, 2016]
• Final Alberta Loss Factors for 2015 [Posted: November 7, 2014] 
• Draft Loss Factors for 2015 [Posted: October 27, 2016];

2015 calibration factors

• Q3 - 2015 Rider E Estimate [Posted: June 26, 2015]  
• Q4 - 2015 Rider E Estimate [Posted: September 30, 2015]  
• Q2 - 2015 Rider E Estimate [Posted: March 31, 2015]  
• Q1- 2015 Rider E Estimate [Posted: December 22, 2014]