SPP's Unprecedented Study Cycle: A Full Breakdown
SPP's DISIS 2024 Phase 1 studies are out. We've never seen anything like this before.
On March 13, 2026, Southwest Power Pool (SPP) posted Phase 1 study results for the DISIS 2024 cluster. With 260 projects representing 66.5 GW of proposed generation capacity, DISIS 2024 is the largest interconnection cluster in SPP history, nearly double the size of the 2023 DISIS in both project count and capacity.
The Phase 1 results reveal a total of $30.2 billion in allocated network upgrade costs across the cluster, with a median cost assignment of $375/kW. Developers in this cluster now have 15 business days to determine whether to proceed in the queue or withdraw their request. Based on historical SPP withdrawal patterns, substantial attrition is likely.
DISIS 2024 Cycle Overview
The cluster’s unprecedented size is partly by design. The application window was extended by roughly five months following SPP’s FERC waiver request. The extension, combined with strong developer interest, produced a cluster more than twice the size of any prior cycle, and the pre-Phase 1 withdrawal rate had already exceeded 30% before a single cost assignment was posted.
Gas comprises the largest share of total active capacity at 17.7 GW across 33 projects. Solar (62 projects, 13.9 GW) and battery storage (74 projects, 13.9 GW) are nearly identical in total capacity. Solar + battery hybrids comprise 43 projects and 10.3 GW. Wind, historically a major resource type in SPP, accounts for just 32 projects and 9 GW, its smallest share of any recent DISIS cluster.