The first quarter of 2026 brought a surge of interconnection activity across the Southeastern Electric Reliability Council (SERC) region. Key updates included:
- Santee Cooper, Tennessee Valley Authority (TVA), Southern Company, and Duke Energy Annual Cluster Windows all opened and closed in Q1
- TVA also issued a Resource Solicitation Cluster (RSC), introducing a parallel pathway for capacity procurement tied to interconnection readiness
- EPE supported multiple clients through successful submissions into Santee Cooper, Southern Company, and TVA’s RSC, navigating compressed timelines, evolving technical requirements, and administrative constraint
Recent Process Changes and Timeline Compression Across SERC
Santee Cooper finalized revisions to its interconnection procedures at the end of 2025, formally adopting FERC Order 2023, aligned cluster study constructs. One major structural change includes the reduction of the application window from 150 calendar days to only 45 days. This change will significantly increase the importance of front-end project readiness, including site control, modeling completeness, and documentation accuracy at the time of submission.
Southern Company concurrently deployed a new interconnection application portal. Early-cycle implementation introduced friction points, most notably around user access controls and the integration of third-party consultants. This change makes additional coordination during time-sensitive submission periods imperative.
Escalation in Modeling and Study Requirements
The transition from a serial study process to a cluster-based framework has materially increased the scope and complexity of required technical deliverables. Developers are now expected to provide a multi-platform modeling package that includes:
- Siemens PTI PSS®E base models
- User-Defined Models (UDMs) and generic dynamic models
- PSCAD/EMT models for inverter-based resource (IBR) performance validation
- Cross-platform benchmarking to ensure consistency between RMS and EMT simulations
These expanded requirements have raised the bar for technical preparedness, particularly within non-jurisdictional utilities such as TVA and Santee Cooper, where historical modeling expectations were less aligned with evolving FERC-driven standards.
Site Control and Application Readiness
Reforms driven by FERC Order 2023 continue to elevate the threshold for site control, with most utilities requiring approximately 90% control at the time of application. Southern Company has maintained a notably stringent interpretation of these requirements, conducting detailed reviews of both land ownership documentation and total acreage relative to project design parameters. Deficiencies in site control remain a leading cause of application risk.
Execution Under Compressed Timelines
Within this evolving framework, successful application outcomes are increasingly dependent on early-stage technical rigor and coordinated execution. In 2026, EPE has leveraged in-house expertise in model development, validation, and benchmarking to support late-stage submissions that successfully cleared deficiency reviews and secured queue positions across multiple utilities.
As Annual Cluster processes mature, developers should anticipate continued emphasis on upfront completeness, higher-fidelity modeling, and stricter administrative gating criteria. Early alignment across engineering, real estate, and regulatory workstreams will be critical to maintaining competitiveness in future cluster windows. To find out how EPE can help you secure queue positions across SERC, contact our team using the form below.
