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    Transmission/Distribution (TX/DX) Coordinated Planning Framework


    The AESO has commenced an initiative to develop, in collaboration with industry, a framework to support the coordination of transmission and distribution planning, to be referred to as the Tx/Dx Coordinated Planning Framework (Tx/Dx Framework). The Tx/Dx Framework is an in-progress AESO Grid initiative.


    The AESO considers that the transformation of the Alberta interconnected electric system (AIES) from the one-way delivery of electric energy to a state of two-way power flows will require increased coordination and planning between the transmission and distribution systems to deliver safe, reliable, and economic operation of the AIES and delivery of electric energy to customers.  As progressive growth of DERs within the distribution networks impacts energy flows in both directions, there is increased value in the coordinated planning between the AESO and DFOs for end-use customers.

    This increased complexity of AIES planning and operation, together with overall AIES infrastructure costs to end-use customers, has resulted in more and deeper scrutiny of all additions and improvements to the AIES by the AESO, industry/ratepayer groups and the AUC. This scrutiny is resulting in longer timelines and additional information requirements for DFO-driven system access service requests.

    The AESO is committed to finding ways to enhance the processes and decision-making framework that affect the AESO’s provisions of system access service and planning of the transmission system. The Tx/Dx Framework will support planning that is in alignment with regulations and legislation, technically sufficient, reliable, and economically efficient solutions across the transmission/distribution interface to minimize increased financial impacts on end-use customers. The AESO’s focus in this initiative will be on the Tx/Dx interface.

    Over the last year, the AESO engaged with TFOs, DFOs, industry and ratepayer groups through a series of collaborative technical sessions to gather feedback, recommendations and to build alignment throughout the development of a decision-making framework document and supporting resources.  These sessions are now complete, and a decision-making framework document and updated Distribution Deficiency Report guideline has been developed. These documents will continue to evolve and improve through implementation and will be actively used in the Connection Process. Stakeholders interested in providing additional comments or for further clarification can direct emails to

     Key focus areas for this targeted engagement

    • Enhancing the AESO’s decision-making process to develop an efficient, transparent and balanced AESO decision-making framework for responding to DFO system access service requests (SASR)

    • Updating and standardizing the AESOs distribution deficiency report (DDR) guideline to ensure all required information is provided by the DFOs with their SASR application

    • Exploring Connection Process improvements for facilitating DFO reliability and capacity SASRs.
    • The transformation of the grid continues to progress at different rates across the province, particularly the increase in DER penetration, increase in variable generation, and corresponding increase in variable power flows at the Tx/Dx interface, driving the need for proactive coordination between the distribution and transmission systems. This focus area will include:

      • alignment of DFO DER hosting capabilities with the capability of the transmission system to integrate generation
      • assessing the value, merits and impacts of probabilistic planning to support the AESO decision-making and planning

    Out-of-Scope for this engagement

    • AESO DER Roadmap Initiative
    • AUC Distribution System Inquiry
    • AESO Energy Storage Roadmap
    • AESO Market & Tariff-related initiatives

    2021 Plan for Tx/Dx Framework initiative activities

    The chart below provides a high-level overview of the Tx/Dx Framework activities that the AESO intends to progress over the next 12 months, while recognizing timing may change as activities progress and more information becomes available. These activities will be conducted with the targeted stakeholder group that has been progressing this initiative over the past year.

    • Q4 2021
      • Continue work on the AESO Connection Process for DFO reliability and capability projects and finalize changes for implementation
      • Include feedback from the Tx/Dx workshops on Transmission capability assessments
      • Identify issues and opportunities with introducing probabilistic planning into AESO work processes
    • Q1 2022
      • Continue work on the AESO Connection Process for DFO reliability and capability projects
      • Create DFO POD guidelines
      • Complete work on the Transmission capability assessments and implement
      • Develop probabilistic planning into AESO work processes, as required
    • Q2 2022
      • Implement changes to the AESO Connection Process for DFO reliability and capability projects
      • Create DFO POD guidelines
      • Develop probabilistic planning into AESO work processes, as required
    • Q4 2022
      • Published Transmission Capability Map in March 2022
      • Implemented changes to the AESO Connection Process for DFO reliability and capability projects
      • Incorporating probabilistic planning into AESO work processes to be explored in 2023
    • Q1 2023
      • Working on the annual update of Transmission Capability Map to be published in early Q2
      • Engage Tx/Dx industry stakeholders for input on the 2023 workplan
    • Q2 2023
      • Publish updated Transmission Capability Map
      • Initiate discussions and analysis on incorporating probabilistic planning into AESO work processes, as required


    Interrelated activities


    If you have any other questions, please contact and subscribe to our stakeholder newsletter for updates.