Skip Links
Sector Participants > IESO News > 2025 Network Model Build Schedule Adjusted to Reflect MRP Launch

News and Updates

2025 Network Model Build Schedule Adjusted to Reflect MRP Launch

April 18, 2024

Updates to pending physical changes in the Ontario power system are conducted through the IESO’s Network Model Build (NMB) process. The NMB updates the mathematical model that is used in real-time security and market tools to reliably and efficiently manage the power system and transact energy with Ontario’s neighbours.

In preparation for the Market Renewal Program (MRP) Go-Live in May 2025, next year’s NMB schedule will be adjusted to ensure that system changes are tested and synchronized in advance.

The IESO has posted the 2025 NMB schedule now to ensure market participants who have projects that need to be incorporated into the IESO’s network model within Q2 2025 (April – June 2025) are aware of the gap in the regular NMB schedule. Any system changes not ready for inclusion in IESO models by early April 2025 cannot be accommodated until the next update window in mid-June 2025. 

The 2025 NMB schedule before and after the MRP Go-Live date of May 1, 2025, are as follows:

  • Last NMB before MRP Go-Live: April 2, 2025 (4 weeks prior to MRP Go-Live)
  • First NMB after MRP Go-Live: June 18, 2025 (~7 weeks after MRP Go-Live)

It is recommended that any participants (i.e., generators, distributors, transmitters, capacity auction participants, or wholesale loads) planning to make physical modification or additions on the grid, including telemetry, contact the IESO at by the end of 2024 to develop a change schedule. 

Information on connecting to Ontario’s power system process can be found on the IESO’s website.

The IESO is committed to working with market participants to ensure a smooth transition to the new market design. Please contact with any questions.

< Back to IESO News