As discussed during the December 5, 2023 EMT presentation to stakeholders (slide 26), the implementation plan for EMT modelling for new inverter-based facilities is as follows:

Inverter-based Facilities Energizing Before September 1, 2024:

• Owners of inverter-based facilities must submit the EMT model and supporting documents during the project post-energization process. For transmission-connected inverter-based resources (IBRs), the validated EMT model must be submitted within 180 days after energization along with the generating unit model validation and reactive power verification report.

Inverter-based Facilities Energizing on or after September 1, 2024:

• Owners of inverter-based facilities must submit the EMT model and supporting documents 100 days before energization. Additionally, for transmission-connected inverter-based resources (IBRs), the validated EMT model must be submitted within 180 days after energization along with the generating unit model validation and reactive power verification report.