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    Recalculated 2009 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 in 2009: 

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

    The AESO must recalculate loss factors and losses charges in accordance with Decisions 790-D04-2016 and 790-D06-2017 of the Alberta Utilities Commission in Proceeding 790, Complaints Regarding the ISO Transmission Loss Factor Rule and Loss Factor Methodology. On August 13, 2021, the AESO advised market participants and other interested parties that it had corrected errors identified in system topologies used in the initial recalculation of Module C loss factors for 2009. For more information, see the update posted in the stakeholder engagement section of the loss factor page here. The corrected 2009 loss factors are provided here: 

    The AESO must provide additional information related to the recalculated loss factors. This additional information is provided here: 

    The initial loss factor postings for the third Module C settlement period, which have been corrected above, remain available below for the interest of stakeholders:

    Actual losses on the transmission system were 2,516 GWh for 2009 and the average loss factor for the transmission system was 4.53% for 2009.