SPP · Southwest Power Pool
The regional grid operator spanning the central US plains, a market regime with its own study sequence, cost allocation, and curtailment obligations.
Current numbers
Maximum 7-year conditional non-firm termSPP CHILLS conditional service term; not a study duration
0.90–1.10 pu continuous; 0.15 s below 0.50 puSPP High Impact Large Load voltage ride-through at the POI (Table 1, 2025-07-08): 0.90–1.10 pu continuous, 2 s at 0.80–0.90 pu, down to 0.15 s below 0.50 pu
18 / 15 / 10 GWcurtailment-enabled headroom at 0.5% in PJM / MISO / ERCOT (SPP also ~10 GW; Southern ~8 GW)