The SPP GIAG convened virtually on May 21, 2025, to discuss critical reforms to the generator interconnection process, including enhancements to the DISIS framework, upcoming policy revisions, and progress on several key initiatives. Here are the highlights from the meeting:
DISIS Reforms: Progress on Multiple Phase One Iterations
The centerpiece of the meeting was a proposal to revise Attachment V of the SPP Tariff, allowing for multiple Phase One iterations within the DISIS (Definitive Interconnection System Impact Study) process. This change aims to address the growing complexity of interconnection clusters and mitigate volatility in upgrade costs caused by project withdrawals early in the study process.
Two motions were considered:
- Vote 1 on a base revision failed (4-6-2).
- Vote 2, which incorporated language for penalty-free withdrawals (without thresholds) after preliminary results but before the end of DP1, was approved (5-0-7).
The revised approach is intended to reduce uncertainty and queue congestion by offering developers a clearer off-ramp earlier in the process. However, concerns remain from SPP staff regarding whether penalty-free withdrawals can be supported under the current tariff.
Additional Updates
- Generator Interconnection (GI) Policy Roadmap: Updates were shared on major policy initiatives including ESRLA, ERAS, CPP, and QOL, with a timeline review for DISIS 2024 and 2026 studies.
- IEEE 2800 Phase 2 (SIR749): Phase 2 implementation of inverter-based resource standards for Grid-Forming BESS was discussed, with feedback due by June 5, 2025.
- CPP Manual and Tariff Updates: Presenters outlined the new CPP Manual development timeline and redlines to Tariff Attachment AY, signaling major procedural and structural changes ahead.
- ESRLA (RR676) and ERAS: Updates were given on timelines, revisions, and organizational review processes.
- DISIS Status and Special Studies: Updates were provided on the current study cycle, including anticipated timelines and project milestones.
Takeaway for Developers
The GIAG continues to evolve the DISIS framework toward greater efficiency and transparency. The approval of multiple Phase One iterations, coupled with the potential for penalty-free withdrawals, marks a significant shift in queue management philosophy. Developers should watch for further guidance on implementation and how these changes may influence project risk and financial planning.
View Meeting Materials
Gain insights in the evolving power grid interconnection landscape. Dive into this month’s comprehensive stakeholder meeting summaries and blog insights to stay informed and ahead of the curve. For more information on ZEG and our services, schedule a free demo today!
