The MISO Interconnection Process Working Group (IPWG) met on December 2 to review the status of generator interconnection reform efforts, persistent modeling quality challenges, and ongoing affected-system coordination issues across one of the largest interconnection queues in North America. The discussion reflected the continued strain placed on MISO’s interconnection framework by unprecedented queue volumes, increasingly complex inverter-based resources, and growing interregional dependencies.
While MISO highlighted incremental improvements resulting from recent process reforms, stakeholders acknowledged that overall timelines remain extended. Modeling quality—particularly dynamic model accuracy—and affected-system coordination continue to be the dominant drivers of delay and uncertainty for developers navigating the queue.
Queue Status and Reform Progress
MISO provided an update on current queue volumes and the observed impacts of recent interconnection reforms. Staff noted that procedural changes have improved sequencing discipline and clarified study milestones, particularly around model submission requirements and readiness checks. However, MISO acknowledged that the scale of the queue continues to overwhelm available engineering and coordination capacity.
Stakeholders emphasized that while reforms have helped reduce ambiguity, they have not fundamentally shortened timelines. Projects routinely span multiple study cycles, and upgrade scopes often evolve as system conditions and assumptions change. Developers expressed concern that extended timelines increase exposure to cost escalation, financing risk, and shifting market conditions.
MISO reiterated that interconnection reform is an ongoing process rather than a one-time fix. As resource characteristics, load patterns, and interregional dependencies evolve, additional adjustments to process design and staffing may be required to stabilize timelines.
Modeling Quality and Validation
Dynamic modeling quality was repeatedly identified as the most significant contributor to study delays. MISO emphasized that deficiencies in inverter-based resource models—particularly related to control behavior, parameter consistency, and documentation—continue to trigger extended review cycles and restudies.
To address this, MISO outlined efforts to introduce stricter validation checkpoints earlier in the study process. The intent is to identify modeling issues before they propagate into later study phases, where corrections are more disruptive and costly. Clearer guidance for inverter-based resources is being developed to reduce interpretation gaps between developers, consultants, and system planners.
Stakeholders broadly supported stronger validation standards but cautioned that increased rigor must be paired with predictable review timelines and consistent application. Several participants noted that evolving expectations can create moving targets for projects already deep in the queue. MISO acknowledged this concern and emphasized the importance of advance notice and transitional treatment where possible.
Affected-System Coordination
Affected-system coordination with neighboring regions—including SPP, PJM, and other transmission providers—remains a significant source of uncertainty. Stakeholders noted that affected-system impacts can introduce delays largely outside MISO’s direct control, complicating project schedules and financial planning.
Developers requested earlier notification of potential affected-system involvement and clearer documentation of study assumptions and results. Earlier visibility into these risks could allow projects to better sequence development activities, manage capital commitments, and engage counterparties proactively.
MISO recognized the challenges inherent in interregional coordination, noting that differences in study methodologies, modeling standards, and timelines continue to limit alignment. While incremental improvements are underway, staff acknowledged that affected-system risk is likely to remain a defining feature of the interconnection landscape.
Transparency and Developer Feedback
Transparency was a recurring theme throughout the meeting. Developers requested improved visibility into intermediate study results, upgrade drivers, and sensitivity assumptions. Greater transparency, they argued, would support more realistic financial planning and reduce late-stage surprises.
MISO noted that confidentiality constraints and data limitations must be respected, but staff is exploring ways to provide more actionable information without compromising the integrity of the study process. The discussion reflected a growing recognition that transparency is essential to maintaining developer confidence amid prolonged timelines and elevated risk.
Implications for Developers and Asset Owners
The December IPWG discussion reinforced that success in the MISO queue increasingly depends on preparation, model quality, and proactive risk management. Poorly prepared models, incomplete documentation, or delayed responses can have cascading effects, extending timelines and increasing exposure to affected-system delays.
As inverter-based resources dominate new queue entries, developers must ensure tight alignment between plant controls, study models, and documented assumptions. Interconnection risk is no longer limited to MISO alone but increasingly shaped by interregional coordination outcomes.
Zero Emission Grid supports developers navigating MISO’s interconnection process by providing dynamic model preparation, validation support, and affected-system strategy development. By anticipating modeling risks, aligning assumptions early, and translating IPWG outcomes into actionable guidance, ZEG helps projects move forward with greater confidence in an increasingly constrained queue environment. Contact us today to get started.
References
Related Summaries from this Month
- ERCOT IBRWG 12.19.25: Reactive Capability at 0 MW, AGS BESS, and NERC Alignment
- ERCOT PLWG 12.16.25: Dispatchable Load Study Reform, GETs in the RTP, and Resiliency Criteria
- ERCOT LLWG 12.11.25: NOGRR282, Large Electronic Load Ride-Through & Frequency Risk
- PJM IPS 12.18.25: Winter Reliability and Planning Model Updates
- PJM TEAC 12.08.25: RTEP Evaluation, Supplemental Needs, and Emerging Cost Allocation Signals
Additional Insights and Resources
- CPUC Proposed Decision 12.24.25: Standard Offer Flexible Service Connections and Energization Timelines
- ERCOT Planning Guide Review: Tightening Assumptions and Performance Expectations
- Hardware-in-the-Loop (HIL) Validation for Large Loads, Data Centers, and Inverter-Based Resources in Modern Power Grids
- CAISO December 2025 Regulatory Report: Planning Acceleration and Policy Alignment
- MISO MTEP Report Summary: Load Growth, Transmission Scale, and Planning Risk Signals
- ISO-NE 2025 Regional System Plan (RSP25): Planning Drivers, Transmission Needs, and Reliability Outlook
