ERCOT's large load interconnection requirements continue to evolve, with increasing focus on the completeness, accuracy, and validation of dynamic models used to study projects before they connect to the ERCOT System.
The latest development is PGRR144 (Dynamic Model Submission and Review Requirements for Large Loads including Large Computational Loads), recently recommended for approval by the ERCOT Technical Advisory Committee (TAC).
PGRR144 is now expected to move to the ERCOT Board of Directors for the next stage of the approval process. The changes will introduce additional requirements and checkpoints for dynamic modeling throughout the large load interconnection process, with particular requirements for Large Computational Loads (LCLs).
A Greater Focus on Dynamic Model Quality
PGRR144 is intended to establish clearer requirements for submitting and maintaining dynamic models for large loads.
Under the proposed changes, dynamic data would need to be provided in formats compatible with the software platforms identified in the ERCOT Dynamics Working Group (DWG) Procedure Manual, including:
The proposal also requires additional validation and testing to demonstrate that submitted models are consistent and benchmarked as well as accurately representing large load behavior during system disturbances.
For all large loads, the proposed requirements include model quality testing to demonstrate voltage ride-through capability. For LCLs, PGRR144 would also require converter model validation reports that benchmark PSCAD models against actual hardware testing. One aspect to keep in mind is that the models are required for the entire facility, including cooling, protection, and controls.
New Model Review Checkpoints Throughout the Interconnection Process
One key concept behind PGRR144 is that dynamic models would not simply be submitted once and remain unchanged throughout the project lifecycle.
Instead, the proposal establishes multiple model review checkpoints during the interconnection process, including:
These checkpoints are intended to improve consistency between the models used in ERCOT studies and the actual facility being constructed and ultimately energized.
For developers, this further reinforces the importance of treating dynamic modeling as an ongoing project requirement rather than a one-time interconnection deliverable.
Changes to Existing Large Computational Loads
PGRR144 also addresses modifications to existing LCL facilities.
Under the proposed language, a modification that materially changes an LCL's dynamic characteristics or operating behavior in a way that may affect voltage or frequency ride-through performance would be subject to ERCOT review.
The proposed process would require updated dynamic models, model quality test results, and supporting simulation files to be submitted to ERCOT and the interconnecting Transmission Service Provider (TSP). Depending on the review results, ERCOT could approve the modification, require additional assessments, or reject the proposed modification where applicable ride-through requirements are not met.
This is an important consideration for LCL owners because changes to technology or operating behavior could potentially trigger additional review requirements even where the facility's MW capacity remains unchanged.
As-Built Model Requirements Before Energization
PGRR144 also adds another important checkpoint for LCL projects approaching Initial Energization.
Before requesting Initial Energization, the proposed requirements would call for updated dynamic models representing the as-built facility, along with documentation identifying differences from the model data previously used in ERCOT's stability assessment process, and an attestation that the submitted data reflects the actual field settings.
This requirement reflects ERCOT's increasing focus on ensuring that the model used for reliability assessments remains aligned with the actual equipment and controls installed in the field.
Why This Matters
PGRR144 is another important step in ERCOT's broader effort to improve visibility into how rapidly growing Large Loads respond during grid disturbances.
As increasingly important reliability considerations continue to grow, this proposal is designed to identify potential model and reliability issues earlier in the interconnection process and consider appropriate mitigation measures before energization. Delays or inability to meet the set requirements could result in projects missing key milestones, further delaying energization.
While PGRR144 is not yet final, its advancement through TAC provides a strong indication of ERCOT's direction toward more structured dynamic model submission, testing, validation, and lifecycle management requirements.
What Comes Next
On August 26, 2026, TAC voted to recommend approval of PGRR144. The revision now moves forward for consideration by the ERCOT Board of Directors. The proposed effective date is currently the first day of the month following PUCT approval.
As the proposal continues through the approval process, developers and large load owners should begin evaluating whether their current modeling, validation, and project configuration management processes are positioned to meet the proposed requirements.
How EPE Can Support ERCOT Projects Following PGRR144
At EPE, we continue to closely follow ERCOT's evolving large load interconnection, modeling, and reliability requirements.
Our team can support large load and LCL projects with:
As ERCOT continues to establish more formal requirements around large load dynamic modeling, early preparation will become increasingly important for maintaining alignment between project design, interconnection studies, and energization requirements.
EPE will continue following PGRR144 through the ERCOT Board approval process and provide updates as the requirements are finalized. To discuss the updates and how they might affect your project, reach out to our team of experts using the form below.
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